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Meeks SL, Zimowski KL. Haemophilia in the era of novel therapies: Where do inhibitors feature in the new landscape? Haemophilia 2024; 30 Suppl 3:95-102. [PMID: 38539060 DOI: 10.1111/hae.14982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 04/22/2024]
Abstract
INTRODUCTION The advent of therapeutic recombinant factor VIII (FVIII) and factor IX (FIX) protein infusions revolutionized the care of persons with haemophilia in the 1990s. It kicked off an era with the increasing use of prophylactic factor infusions for patients and transformed conversations around the ideal trough activity levels as well as the ultimate goals in tailored, individualized care. Our knowledge surrounding the immunologic basis of inhibitor development and treatment derives from a time when patients were receiving frequent factor infusions and focused on immune tolerance induction following inhibitor development. DISCUSSION More recently, care was revolutionized again in haemophilia A with the approval of emicizumab, a bispecific antibody mimicking activated FVIII function, to prevent bleeding. The use of emicizumab prophylaxis has resulted in a significantly slower accumulation of factor exposure days and continued effective prophylaxis in the case of inhibitor development. While emicizumab is effective at reducing the frequency of bleeding events in patients with haemophilia A, management of breakthrough bleeds, trauma, and surgeries still requires additional treatment. Ensuring that FVIII is a therapeutic option, particularly for life-threatening bleeding events and major surgeries is critical to optimizing the care of persons with haemophilia A. Other novel non-factor concentrate therapies, including rebalancing agents, will dramatically change the landscape for persons with haemophilia B with inhibitors. CONCLUSION This review discusses the changing landscape regarding the timing of inhibitor development and management strategies after inhibitor development, stressing the importance of education across the community to continue to vigilantly monitor for inhibitors and be prepared to treat persons with inhibitors.
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Affiliation(s)
- Shannon L Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Emory University School of Medicine, Atlanta, Georgia, USA
| | - Karen L Zimowski
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta and Emory University School of Medicine, Atlanta, Georgia, USA
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Batsuli G, Ito J, York ES, Cox C, Baldwin W, Gill S, Lollar P, Meeks SL. Factor VIII antibody immune complexes modulate the humoral response to factor VIII in an epitope-dependent manner. Front Immunol 2023; 14:1233356. [PMID: 37720212 PMCID: PMC10501482 DOI: 10.3389/fimmu.2023.1233356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/11/2023] [Indexed: 09/19/2023] Open
Abstract
Introduction Soluble antigens complexed with immunoglobulin G (IgG) antibodies can induce robust adaptive immune responses in vitro and in animal models of disease. Factor VIII immune complexes (FVIII-ICs) have been detected in individuals with hemophilia A and severe von Willebrand disease following FVIII infusions. Yet, it is unclear if and how FVIII-ICs affect antibody development over time. Methods In this study, we analyzed internalization of FVIII complexed with epitope-mapped FVIII-specific IgG monoclonal antibodies (MAbs) by murine bone marrow-derived dendritic cells (BMDCs) in vitro and antibody development in hemophilia A (FVIII-/-) mice injected with FVIII-IC over time. Results FVIII complexed with 2-116 (A1 domain MAb), 2-113 (A3 domain MAb), and I55 (C2 domain MAb) significantly increased FVIII uptake by BMDC but only FVIII/2-116 enhanced antibody titers in FVIII-/- mice compared to FVIII alone. FVIII/4A4 (A2 domain MAb) showed similar FVIII uptake by BMDC to that of isolated FVIII yet significantly increased antibody titers when injected in FVIII-/- mice. Enhanced antibody responses observed with FVIII/2-116 and FVIII/4A4 complexes in vivo were abrogated in the absence of the FVIII carrier protein von Willebrand factor. Conclusion These findings suggest that a subset of FVIII-IC modulates the humoral response to FVIII in an epitope-dependent manner, which may provide insight into the antibody response observed in some patients with hemophilia A.
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Affiliation(s)
- Glaivy Batsuli
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, GA, United States
| | - Jasmine Ito
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, GA, United States
| | - Elizabeth S. York
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, GA, United States
| | - Courtney Cox
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, GA, United States
| | - Wallace Baldwin
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, GA, United States
| | - Surinder Gill
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, GA, United States
| | - Pete Lollar
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, GA, United States
| | - Shannon L. Meeks
- Department of Pediatrics, Emory University, Atlanta, GA, United States
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Atlanta, GA, United States
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Tran DQ, Benson CC, Boice JA, Chitlur M, Dunn AL, Escobar MA, Gupta K, Johnsen JM, Jorgenson J, Martin SD, Martin S, Meeks SL, Narvaez AA, Quon DV, Reding MT, Reiss UM, Savage B, Schafer K, Steiner B, Thornburg C, Volland LM, von Drygalski A. Building the foundation for a community-generated national research blueprint for inherited bleeding disorders: research priorities to transform the care of people with hemophilia. Expert Rev Hematol 2023; 16:19-37. [PMID: 36920859 PMCID: PMC10020869 DOI: 10.1080/17474086.2023.2171981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/19/2023] [Indexed: 03/16/2023]
Abstract
BACKGROUND Decades of research have transformed hemophilia from severely limiting children's lives to a manageable disorder compatible with a full, active life, for many in high-income countries. The direction of future research will determine whether exciting developments truly advance health equity for all people with hemophilia (PWH). National Hemophilia Foundation (NHF) and American Thrombosis and Hemostasis Network conducted extensive inclusive all-stakeholder consultations to identify the priorities of people with inherited bleeding disorders and those who care for them. RESEARCH DESIGN AND METHODS Working group (WG) 1 of the NHF State of the Science Research Summit distilled the community-identified priorities for hemophilia A and B into concrete research questions and scored their feasibility, impact, and risk. RESULTS WG1 defined 63 top priority research questions concerning arthropathy/pain/bone health, inhibitors, diagnostics, gene therapy, the pediatric to adult transition of care, disparities faced by the community, and cardiovascular disease. This research has the potential to empower PWH to thrive despite lifelong comorbidities and achieve new standards of wellbeing, including psychosocial. CONCLUSIONS Collaborative research and care delivery will be key to capitalizing on current and horizon treatments and harnessing technical advances to improve diagnostics and testing, to advance health equity for all PWH.
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Affiliation(s)
- Duc Q. Tran
- Hemophilia of Georgia Center for Bleeding & Clotting Disorders of Emory, Emory University, Atlanta, Georgia, USA
| | - Craig C. Benson
- Sanofi ¬ Rare and Rare Blood Disorders Development, Cambridge, Massachusetts, USA
| | | | - Meera Chitlur
- Division of Hematology/Oncology, Central Michigan University College of Medicine, Detroit, Michigan, USA
| | - Amy L. Dunn
- Division of Hematology, Oncology and Bone Marrow Transplant, Nationwide Children’s Hospital, Columbus, Ohio, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Miguel A. Escobar
- Division of Hematology, UTHealth Houston McGovern Medical School, Gulf States Hemophilia and Thrombophilia Center, Houston, Texas, USA
| | - Kalpna Gupta
- Center for Bleeding and Clotting Disorders, Division Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, Minnesota, USA
- Division of Hematology/Oncology, Department of Medicine, University of California, Irvine, California, USA
| | - Jill M. Johnsen
- Bloodworks Northwest, Seattle, Washington, USA
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Washington Center for Bleeding Disorders, Seattle, Washington, USA
| | | | | | - Suzanne Martin
- Bleeding Disorders Association of South Carolina, Greenville, South Carolina, USA
| | - Shannon L. Meeks
- Hemophilia of Georgia Center for Bleeding & Clotting Disorders of Emory, Emory University, Atlanta, Georgia, USA
- Children’s Healthcare of Atlanta Inc Aflac Cancer and Blood Disorders Center, Atlanta, Georgia, USA
| | - Alfredo A Narvaez
- Louisiana Center for Bleeding & Clotting Disorders, Tulane University, New Orleans, Louisiana, USA
| | - Doris V. Quon
- Orthopaedic Hemophilia Treatment Center, Orthopaedic Hospital of Los Angeles, California, USA
| | - Mark T. Reding
- Center for Bleeding and Clotting Disorders, Division Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ulrike M. Reiss
- Department of Hematology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Brittany Savage
- Indiana Hemophilia and Thrombosis Center, Indianapolis, Indiana, USA
| | - Kim Schafer
- Davis Hemostasis and Thrombosis Center, University of California Davis, Sacramento, California, USA
| | - Bruno Steiner
- Washington Center for Bleeding Disorders, Seattle, Washington, USA
| | - Courtney Thornburg
- Rady Children’s Hospital-San Diego, San Diego, California, USA
- UC San Diego, La Jolla, California, USA
| | | | - Annette von Drygalski
- Hemophilia & Thrombosis Treatment Center, University of California San Diego, California, USA
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Zerra PE, Parker ET, Baldwin WH, Healey JF, Patel SR, McCoy JW, Cox C, Stowell SR, Meeks SL. Engineering a Therapeutic Protein to Enhance the Study of Anti-Drug Immunity. Biomedicines 2022; 10:1724. [PMID: 35885029 PMCID: PMC9313379 DOI: 10.3390/biomedicines10071724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/29/2022] [Accepted: 07/04/2022] [Indexed: 11/16/2022] Open
Abstract
The development of anti-drug antibodies represents a significant barrier to the utilization of protein-based therapies for a wide variety of diseases. While the rate of antibody formation can vary depending on the therapeutic employed and the target patient population receiving the drug, the antigen-specific immune response underlying the development of anti-drug antibodies often remains difficult to define. This is especially true for patients with hemophilia A who, following exposure, develop antibodies against the coagulation factor, factor VIII (FVIII). Models capable of studying this response in an antigen-specific manner have been lacking. To overcome this challenge, we engineered FVIII to contain a peptide (323-339) from the model antigen ovalbumin (OVA), a very common tool used to study antigen-specific immunity. FVIII with an OVA peptide (FVIII-OVA) retained clotting activity and possessed the ability to activate CD4 T cells specific to OVA323-339 in vitro. When compared to FVIII alone, FVIII-OVA also exhibited a similar level of immunogenicity, suggesting that the presence of OVA323-339 does not substantially alter the anti-FVIII immune response. Intriguingly, while little CD4 T cell response could be observed following exposure to FVIII-OVA alone, inclusion of anti-FVIII antibodies, recently shown to favorably modulate anti-FVIII immune responses, significantly enhanced CD4 T cell activation following FVIII-OVA exposure. These results demonstrate that model antigens can be incorporated into a therapeutic protein to study antigen-specific responses and more specifically that the CD4 T cell response to FVIII-OVA can be augmented by pre-existing anti-FVIII antibodies.
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Affiliation(s)
- Patricia E. Zerra
- Center for Transfusion Medicine and Cellular Therapies, Department of Laboratory Medicine and Pathology, Emory University, Atlanta, GA 30322, USA; (P.E.Z.); (J.W.M.)
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (E.T.P.); (W.H.B.); (J.F.H.); (S.R.P.); (C.C.)
| | - Ernest T. Parker
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (E.T.P.); (W.H.B.); (J.F.H.); (S.R.P.); (C.C.)
| | - Wallace Hunter Baldwin
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (E.T.P.); (W.H.B.); (J.F.H.); (S.R.P.); (C.C.)
| | - John F. Healey
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (E.T.P.); (W.H.B.); (J.F.H.); (S.R.P.); (C.C.)
| | - Seema R. Patel
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (E.T.P.); (W.H.B.); (J.F.H.); (S.R.P.); (C.C.)
| | - James W. McCoy
- Center for Transfusion Medicine and Cellular Therapies, Department of Laboratory Medicine and Pathology, Emory University, Atlanta, GA 30322, USA; (P.E.Z.); (J.W.M.)
| | - Courtney Cox
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (E.T.P.); (W.H.B.); (J.F.H.); (S.R.P.); (C.C.)
| | - Sean R. Stowell
- Joint Program in Transfusion Medicine, Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Shannon L. Meeks
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University, Atlanta, GA 30322, USA; (E.T.P.); (W.H.B.); (J.F.H.); (S.R.P.); (C.C.)
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Patel SR, Lundgren TS, Baldwin WH, Cox C, Parker ET, Healey JF, Jajosky RP, Zerra PE, Josephson CD, Doering CB, Stowell SR, Meeks SL. Neutralizing Antibodies Against Factor VIII Can Occur Through a Non-Germinal Center Pathway. Front Immunol 2022; 13:880829. [PMID: 35634288 PMCID: PMC9132091 DOI: 10.3389/fimmu.2022.880829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
Humoral immunity to factor VIII (FVIII) represents a significant challenge for the treatment of patients with hemophilia A. Current paradigms indicate that neutralizing antibodies against FVIII (inhibitors) occur through a classical CD4 T cell, germinal center (GC) dependent process. However, clinical observations suggest that the nature of the immune response to FVIII may differ between patients. While some patients produce persistent low or high inhibitor titers, others generate a transient response. Moreover, FVIII reactive memory B cells are only detectable in some patients with sustained inhibitor titers. The determinants regulating the type of immune response a patient develops, let alone how the immune response differs in these patients remains incompletely understood. One hypothesis is that polymorphisms within immunoregulatory genes alter the underlying immune response to FVIII, and thereby the inhibitor response. Consistent with this, studies report that inhibitor titers to FVIII differ in animals with the same F8 pathogenic variant but completely distinct backgrounds; though, how these genetic disparities affect the immune response to FVIII remains to be investigated. Given this, we sought to mechanistically dissect how genetics impact the underlying immune response to FVIII. In particular, as the risk of producing inhibitors is weakly associated with differences in HLA, we hypothesized that genetic factors other than HLA influence the immune response to FVIII and downstream inhibitor formation. Our data demonstrate that FVIII deficient mice encoding the same MHC and F8 variant produce disparate inhibitor titers, and that the type of inhibitor response formed associates with the ability to generate GCs. Interestingly, the formation of antibodies through a GC or non-GC pathway does not appear to be due to differences in CD4 T cell immunity, as the CD4 T cell response to an immunodominant epitope in FVIII was similar in these mice. These results indicate that genetics can impact the process by which inhibitors develop and may in part explain the apparent propensity of patients to form distinct inhibitor responses. Moreover, these data highlight an underappreciated immunological pathway of humoral immunity to FVIII and lay the groundwork for identification of biomarkers for the development of approaches to tolerize against FVIII.
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Affiliation(s)
- Seema R Patel
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States
| | - Taran S Lundgren
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States.,Graduate Program in Molecular and Systems Pharmacology, Laney Graduate School, Emory University School of Medicine, Atlanta, GA, United States
| | - Wallace Hunter Baldwin
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States
| | - Courtney Cox
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States
| | - Ernest T Parker
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States
| | - John F Healey
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States
| | - Ryan P Jajosky
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Patricia E Zerra
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States.,Center for Transfusion Medicine and Cellular Therapies, Department of Laboratory Medicine and Pathology, Emory University School of Medicine, Atlanta, GA, United States
| | - Cassandra D Josephson
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States
| | - Christopher B Doering
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States
| | - Sean R Stowell
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University School of Medicine, Atlanta, GA, United States
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6
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Escuriola Ettingshausen C, Yang R, Wu W, Meeks SL. Inhibitors: Diagnostic challenges, unknowns of inhibitor development, treatment of bleeding and surgery, and insights into diagnosis and treatment in China. Haemophilia 2022; 28 Suppl 4:111-118. [PMID: 35521731 DOI: 10.1111/hae.14553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/07/2022] [Accepted: 03/07/2022] [Indexed: 11/30/2022]
Abstract
Factor (F) VIII inhibitors develop in around 30% of previously untreated patients (PUPs) with severe haemophilia, to a lesser extend in moderate and mild haemophilia A and in up to 10% in severe haemophilia B. Diagnostic challenges and questions remain including access to high quality testing, the role for functional inhibitor testing and binding antibody testing, and the adaptations needed in the presence of non-factor replacement therapy. Despite significant gains in knowledge there are still many unanswered questions underlying the immunologic mechanisms of inhibitor development and tolerance. Therapeutic options include eradication of inhibitors using immune tolerance induction therapy (ITI), prophylaxis with bypassing agents (i.e., recombinant activated factor VII /rFVIIa or activated prothrombin complex concentrate/aPCC) or non-factor replacement therapies (e.g., emicizumab) and treatment of bleeds or coverage of surgeries/invasive procedure. Recently a haemophilia centre capacity building program was launched in China to further develop the infrastructure and support needed to improve the diagnosis of haemophilia, detection of inhibitors, and continue to improve the care of patients with haemophilia and inhibitors.
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Affiliation(s)
| | - Renchi Yang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Wenman Wu
- Department of Laboratory Medicine, Ruijin Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta and Department of Pediatrics, Emory University, Atlanta, Georgia, USA
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Négrier C, Oldenburg J, Kenet G, Meeks SL, Bordet JC, Müller J, Le Quellec S, Turecek PL, Tripkovic N, Dargaud Y. Recombinant porcine factor VIII corrects thrombin generation in vitro in plasma from patients with congenital hemophilia A and inhibitors. Res Pract Thromb Haemost 2022; 6:e12731. [PMID: 35765670 PMCID: PMC9207117 DOI: 10.1002/rth2.12731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 03/16/2022] [Accepted: 04/10/2022] [Indexed: 11/21/2022] Open
Abstract
Background Neutralizing factor VIII (FVIII) antibodies are a major complication in hemophilia A. Antihemophilic factor VIII (recombinant), porcine sequence (rpFVIII; susoctocog alfa; Baxalta US Inc., a Takeda company) has low cross‐reactivity to anti‐human FVIII antibodies and can provide functional FVIII activity in the presence of FVIII inhibitors. Objectives Evaluate in vitro thrombin generation and clot formation responses to rpFVIII in blood from patients with congenital hemophilia A. Methods In this multicenter study, blood was obtained for in vitro analyses that included human and porcine FVIII inhibitors, low <5 Bethesda units (BU)/ml or high ≥5 BU/ml titer (Nijmegen‐modified Bethesda assay); thrombin generation assay (TGA), clot viscoelasticity (thromboelastography), fibrin clot structure analysis (scanning electron microscopy), and epitope mapping. Results Blood samples were from 20 patients with congenital hemophilia A (FVIII activity <1%, mean [range] inhibitor titers: anti‐human FVIII, 14 [1–427] BU/ml [n = 13 high, n = 6 low, n = 1 data unavailable]); anti‐porcine FVIII, 12 (0–886) BU/ml (n = 11 high, n = 8 low, n = 1 data unavailable). Porcine inhibitor titer and TGA response measured by endogenous thrombin potential showed an inverse correlation (2.7–10.8 U/ml rpFVIII Spearman correlation coefficient: −0.594 to −0.773; p < 0.01). Clot structures in low anti‐porcine inhibitor titer plasmas were similar to those in noninhibitor plasma. Conclusions Recombinant porcine factor VIII demonstrated a dose‐dependent correction of thrombin generation and clot formation in vitro, dependent on the anti‐porcine FVIII inhibitor titer. Procoagulant responses to rpFVIII occurred in plasma containing FVIII inhibitors.
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Affiliation(s)
- Claude Négrier
- Unite d'Hemostase Clinique Centre National de Reference de l'Hemophilie Hopital Louis Pradel Universite Lyon1 Lyon France
| | - Johannes Oldenburg
- Institute of Experimental Haematology and Transfusion Medicine University Clinic Bonn Bonn Germany
| | - Gili Kenet
- National Hemophilia Center Sheba Medical Center Tel Hashomer and The Amalia Biron Thrombosis Research Institute Tel Aviv University Tel Aviv Israel
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center Emory University School of Medicine Children's Healthcare of Atlanta Atlanta Georgia USA
| | - Jean-Claude Bordet
- Unite d'Hemostase Clinique Centre National de Reference de l'Hemophilie Hopital Louis Pradel Universite Lyon1 Lyon France
| | - Jens Müller
- Institute of Experimental Haematology and Transfusion Medicine University Clinic Bonn Bonn Germany
| | - Sandra Le Quellec
- Unite d'Hemostase Clinique Centre National de Reference de l'Hemophilie Hopital Louis Pradel Universite Lyon1 Lyon France
| | | | | | - Yesim Dargaud
- Unite d'Hemostase Clinique Centre National de Reference de l'Hemophilie Hopital Louis Pradel Universite Lyon1 Lyon France
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8
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Pipe SW, Hermans C, Chitlur M, Carcao M, Castaman G, Davis JA, Ducore J, Dunn AL, Escobar M, Journeycake J, Khan O, Mahlangu J, Meeks SL, Mitha IH, Négrier C, Nowak-Göttl U, Recht M, Chrisentery-Singleton T, Stasyshyn O, Vilchevska KV, Martinez LV, Wang M, Windyga J, Young G, Alexander WA, Bonzo D, Macie C, Mitchell IS, Sauty E, Wilkinson TA, Shapiro AD. Eptacog beta efficacy and safety in the treatment and control of bleeding in paediatric subjects (<12 years) with haemophilia A or B with inhibitors. Haemophilia 2022; 28:548-556. [PMID: 35475308 PMCID: PMC9542908 DOI: 10.1111/hae.14563] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/12/2022] [Accepted: 03/27/2022] [Indexed: 01/19/2023]
Abstract
Introduction Eptacog beta is a new recombinant activated human factor VII bypassing agent approved in the United States for the treatment and control of bleeding in patients with haemophilia A or B with inhibitors 12 years of age or older. Aim To prospectively assess in a phase 3 clinical trial (PERSEPT 2) eptacog beta efficacy and safety for treatment of bleeding in children <12 years of age with haemophilia A or B with inhibitors. Methods Using a randomised crossover design, subjects received initial doses of 75 or 225 μg/kg eptacog beta followed by 75 μg/kg dosing at predefined intervals (as determined by clinical response) to treat bleeding episodes (BEs). Treatment success criteria included a haemostasis evaluation of ‘excellent’ or ‘good’ without use of additional eptacog beta, alternative haemostatic agent or blood product, and no increase in pain following the first ‘excellent’ or ‘good’ assessment. Results Treatment success proportions in 25 subjects (1–11 years) who experienced 546 mild or moderate BEs were 65% in the 75 μg/kg initial dose regimen (IDR) and 60% in the 225 μg/kg IDR 12 h following initial eptacog beta infusion. By 24 h, the treatment success proportions were 97% for the 75 μg/kg IDR and 98% for the 225 μg/kg IDR. No thrombotic events, allergic reactions, neutralising antibodies or treatment‐related adverse events were reported. Conclusion Both 75 and 225 μg/kg eptacog beta IDRs provided safe and effective treatment and control of bleeding in children <12 years of age.
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Affiliation(s)
| | - Cédric Hermans
- Cliniques Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Meera Chitlur
- Children's Hospital of Michigan, Central Michigan University, Detroit, Michigan, USA
| | - Manuel Carcao
- The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Giancarlo Castaman
- Center for Bleeding Disorders and Coagulation, Careggi University Hospital, Florence, Italy
| | - Joanna A Davis
- Pediatric Hemophilia Treatment Center, University of Miami, Miami, Florida, USA
| | - Jonathan Ducore
- Hematology/Oncology Clinic, University of California at Davis, Sacramento, California, USA
| | - Amy L Dunn
- Nationwide Children's Hospital, Department of Pediatrics at The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Miguel Escobar
- University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Janna Journeycake
- Oklahoma Center for Bleeding and Clotting Disorders at OU Health, Oklahoma City, Oklahoma, USA
| | - Osman Khan
- Oklahoma Center for Bleeding and Clotting Disorders at OU Health, Oklahoma City, Oklahoma, USA
| | - Johnny Mahlangu
- Hemophilia Comprehensive Care Center, University of the Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa
| | - Shannon L Meeks
- Emory University and Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, Georgia, USA
| | | | | | - Ulrike Nowak-Göttl
- Institute of Clinical Chemistry, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Michael Recht
- American Thrombosis and Hemostasis Network, Rochester, New York, USA.,Oregon Health & Science University, Portland, Oregon, USA
| | | | | | | | | | - Michael Wang
- Hemophilia and Thrombosis Center, University of Colorado, Aurora, Colorado, USA
| | - Jerzy Windyga
- Department of Hemostasis Disorders and Internal Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - Guy Young
- Children's Hospital Los Angeles, Los Angeles, California, USA.,Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | | | | | | | | | - Evelyne Sauty
- LFB, Laboratoire français du fractionnement et des biotechnologies, Les Ulis, France
| | | | - Amy D Shapiro
- Indiana Hemophilia and Thrombosis Center, Indianapolis, Indiana, USA
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9
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Doshi BS, Rana J, Castaman G, Shaheen MA, Kaczmarek R, Butterfield JS, Meeks SL, Leissinger C, Biswas M, Arruda VR. B cell-activating factor modulates the factor VIII immune response in hemophilia A. J Clin Invest 2021; 131:142906. [PMID: 33651716 PMCID: PMC8262462 DOI: 10.1172/jci142906] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 02/23/2021] [Indexed: 01/19/2023] Open
Abstract
Inhibitors of factor VIII (FVIII) remain the most challenging complication of FVIII protein replacement therapy in hemophilia A (HA). Understanding the mechanisms that guide FVIII-specific B cell development could help identify therapeutic targets. The B cell-activating factor (BAFF) cytokine family is a key regulator of B cell differentiation in normal homeostasis and immune disorders. Thus, we used patient samples and mouse models to investigate the potential role of BAFF in modulating FVIII inhibitors. BAFF levels were elevated in pediatric and adult HA inhibitor patients and decreased to levels similar to those of noninhibitor controls after successful immune tolerance induction (ITI). Moreover, elevations in BAFF levels were seen in patients who failed to achieve FVIII tolerance with anti-CD20 antibody-mediated B cell depletion. In naive HA mice, prophylactic anti-BAFF antibody therapy prior to FVIII immunization prevented inhibitor formation and this tolerance was maintained despite FVIII exposure after immune reconstitution. In preimmunized HA mice, combination therapy with anti-CD20 and anti-BAFF antibodies dramatically reduced FVIII inhibitors via inhibition of FVIII-specific plasma cells. Our data suggest that BAFF may regulate the generation and maintenance of FVIII inhibitors and/or anti-FVIII B cells. Finally, anti-CD20/anti-BAFF combination therapy may be clinically useful for ITI.
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Affiliation(s)
- Bhavya S Doshi
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Divison of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jyoti Rana
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Giancarlo Castaman
- Center for Bleeding Disorders and Coagulation, Careggi University Hospital, Florence, Italy
| | - Mostafa A Shaheen
- Divison of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Radoslaw Kaczmarek
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - John Ss Butterfield
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Shannon L Meeks
- Department of Pediatrics, Aflac Cancer Center and Blood Disorders Center at Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Cindy Leissinger
- Section of Hematology/Oncology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Moanaro Biswas
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Valder R Arruda
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Divison of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Raymond G. Perelman Center for Cellular and Molecular Therapies, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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10
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Willoughby TR, Boczkowski A, Meeks SL, Bova FJ, Zeidan OA, Erhart K, Kelly P. Design and characterization of a prototype tertiary device for proton beam stereotactic radiosurgery. Biomed Phys Eng Express 2021; 7. [PMID: 34087816 DOI: 10.1088/2057-1976/ac086b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/04/2021] [Indexed: 11/12/2022]
Abstract
Though potentially beneficial, proton beam stereotactic radiosurgery has not been adopted widely secondary to the technical challenge of safely delivering multiple focused beams of proton radiation. In this study, we describe the design and characterization of a proton beam stereotactic radiosurgery system that can be adopted by existing passive scattering systems. This system utilizes a helmet-like device in which patient-specific brass apertures required for final beam collimation are positioned on a scaffold that is separate from the treatment gantry. The proton snout is then fitted with a generic aperture to focus the primary proton beam onto the patient specific apertures that are in the helmet-like device. The patient-specific apertures can all be placed at the start of the treatment, thus treatment with multiple beams can be accomplished without the delay of switching the apertures. In this report we describe a prototype design of this collimation system and dosimetric testing to verify efficacy. Subsequently, we describe a custom 3D printing of a prototype device and report on overall localization accuracy using Winston-Lutz tests. Our results show that it is possible to develop an add-on device for proton beam radiosurgery that is safe and efficient and capable of wide adoption on existing proton delivery systems.
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Affiliation(s)
- T R Willoughby
- Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL, United States of America
| | - A Boczkowski
- Department of Neurosurgery, University of Florida, Gainesville, FL, United States of America
| | - S L Meeks
- Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL, United States of America
| | - F J Bova
- Department of Neurosurgery, University of Florida, Gainesville, FL, United States of America
| | - O A Zeidan
- Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL, United States of America
| | - K Erhart
- DotDecimal, Sanford, FL, United States of America
| | - P Kelly
- Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL, United States of America
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11
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Batsuli G, Greene A, Meeks SL, Sidonio RF. Emicizumab in tolerized patients with hemophilia A with inhibitors: A single-institution pediatric cohort assessing inhibitor status. Res Pract Thromb Haemost 2021; 5:342-348. [PMID: 33733033 PMCID: PMC7938619 DOI: 10.1002/rth2.12475] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/20/2020] [Accepted: 11/27/2020] [Indexed: 12/25/2022] Open
Abstract
Background The majority of patients with hemophilia A with inhibitors who undergo immune tolerance induction (ITI) achieve successful tolerance and transition to factor VIII (FVIII) prophylaxis. A portion of these patients have switched to emicizumab for bleeding prevention. However, the risk of inhibitor relapse on emicizumab is unclear. Objective To evaluate the inhibitor status of patients with hemophilia A and inhibitors who achieved successful/partial tolerance after ITI and transitioned from FVIII prophylaxis to emicizumab. Methods This is a single-institution, retrospective review of pediatric patients with severe hemophilia A who have completed ITI with FVIII and switched to emicizumab. Results/Conclusions Seven successfully tolerized and five partially tolerized patients were identified. Three patients continued intermittent FVIII infusions on emicizumab at 50-70 IU/kg twice weekly, once weekly, or every other week due to concerns for inhibitor relapse or loss of recent FVIII tolerance by the treating provider. Eleven of 12 patients (92%) maintained negative inhibitor titers at a mean follow-up of 14.2 ± 6.1 months. One individual had an inhibitor relapse with a peak titer of 2.5 BU/mL. Five of the 11 patients (45%) with negative inhibitor titers had detectable nonneutralizing anti-FVIII IgG4 antibodies, but none of the patients had detectable IgG1 antibodies. There were no inhibitor recurrences in a subset of six patients after FVIII re-exposure for bleeding events or surgery. Given that the presence of an inhibitor significantly impacts factor product choice for bleeding management, ongoing inhibitor monitoring in tolerized patients with hemophilia A who transition to emicizumab is strongly recommended.
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Affiliation(s)
- Glaivy Batsuli
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta Atlanta GA USA.,Department of Pediatrics Emory University Atlanta GA USA
| | - Amanda Greene
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta Atlanta GA USA.,Department of Pediatrics Emory University Atlanta GA USA
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta Atlanta GA USA.,Department of Pediatrics Emory University Atlanta GA USA
| | - Robert F Sidonio
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta Atlanta GA USA.,Department of Pediatrics Emory University Atlanta GA USA
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12
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Batsuli G, Zimowski KL, Carroll R, White MH, Woods GM, Meeks SL, Sidonio RF. Successful Perioperative Management of Orthotopic Cardiac Transplantation in a Pediatric Patient With Concurrent Congenital von Willebrand Disease and Acquired von Willebrand Syndrome Using Recombinant von Willebrand Factor. J Cardiothorac Vasc Anesth 2021; 36:724-727. [PMID: 33618961 DOI: 10.1053/j.jvca.2021.01.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/31/2020] [Accepted: 01/19/2021] [Indexed: 01/18/2023]
Abstract
Von Willebrand disease (VWD) is the most common bleeding disorder and reportedly affects 1:1,000 of the world's population. There are three subtypes of VWD characterized by a quantitative defect (types 1 and 3 VWD) or a qualitative defect (type 2 VWD). Type 1 VWD results in a partial deficiency of von Willebrand factor (VWF) and affects approximately 75% of individuals with VWD, whereas type 3 VWD results in a severe or complete deficiency of VWF. Individuals with type 2 VWD subtypes (types 2A, 2B, 2M, and 2N VWD) express a dysfunctional VWF protein that has impaired interactions with platelets or factor VIII. The majority of individuals with VWD have mild type 1 VWD and occasionally require bolus infusions of VWF for severe bleeding or major surgery. A subset of patients, especially those with type 2A or 3 VWD, may require more frequent VWF replacement or prophylaxis for refractory bleeding or bleeding prevention, respectively. Acquired von Willebrand syndrome (AVWS) is a rare bleeding disorder that primarily occurs as a result of an underlying disease or other pathologic mechanism. Cases of AVWS associated with heart valve defects, left ventricular assist devices, or congenital cardiac disease result from high shear stress in the circulation that induces VWF unfolding and subsequent proteolysis of high-molecular-weight multimers by ADAMTS-13. In rare instances, plasma-derived factor VIII-containing VWF concentrates have been administered to individuals with AVWS for persistent or challenging bleeding events. In this case report, the hemostatic challenges and the perioperative management of cardiac transplantation surgery using a novel recombinant VWF product in a pediatric patient diagnosed with AVWS concomitant with congenital type 1 VWD are described. Written informed consent was obtained from the patient's mother for this case report. The diagnosis of congenital VWD remains a challenge because of multiple potential modifiers that can alter VWF laboratory results. Concurrent conditions, such as congenital heart disease and the rare secondary condition of AVWS, in addition to congenital VWD, can further affect interpretation of coagulation studies. This can result in delays in diagnosis, increase severity of the bleeding phenotype, and complicate hemostatic management in individuals at risk for bleeding and thrombosis. A multidisciplinary approach, including anesthesiologists, cardiologists, cardiovascular surgeons, hematologists, and pharmacists, is critical to achieving optimal patient outcomes, as highlighted in this case report. As diagnostic capabilities and understanding of VWD broaden, future studies evaluating alternative treatment approaches for individuals with various types of VWD would be of great benefit to the medical community.
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Affiliation(s)
- Glaivy Batsuli
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, GA; Department of Pediatrics, Emory University, Atlanta, GA.
| | - Karen L Zimowski
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, GA; Department of Pediatrics, Emory University, Atlanta, GA
| | - Rachel Carroll
- Department of Pharmacy, Children's Healthcare of Atlanta, Atlanta, GA
| | - Michael H White
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, GA; Department of Pediatrics, Emory University, Atlanta, GA
| | - Gary M Woods
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, GA; Department of Pediatrics, Emory University, Atlanta, GA
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, GA; Department of Pediatrics, Emory University, Atlanta, GA
| | - Robert F Sidonio
- Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Atlanta, GA; Department of Pediatrics, Emory University, Atlanta, GA
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13
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Meeks SL, Lacroix-Desmazes S. Emerging benefits of Fc fusion technology in the context of recombinant factor VIII replacement therapy. Haemophilia 2020; 26:958-965. [PMID: 32885562 PMCID: PMC7818509 DOI: 10.1111/hae.14123] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 12/15/2022]
Abstract
Although the primary reason for recombinant factor VIII Fc fusion protein (rFVIIIFc) development was to reduce treatment burden associated with routine prophylaxis, new evidence suggests additional benefits of Fc fusion technology in the treatment of people with haemophilia A. Preclinical research has been utilized to characterize the potential immunomodulatory properties of rFVIIIFc, including an ability to reduce inflammation and induce tolerance to factor VIII. This has since been expanded into clinical research in immune tolerance induction (ITI) with rFVIIIFc, results of which suggest the potential for rapid tolerization in first‐time ITI patients and therapeutic benefit in patients undergoing rescue ITI. The potential for improved joint health through the anti‐inflammatory properties of rFVIIIFc has also been suggested. In addition, a new avenue of research into the role of rFVIIIFc in promoting bone health in patients with haemophilia A, potentially through reduced osteoclast formation, has yielded encouraging results that support further study. This review summarizes the existing preclinical and clinical studies of immunomodulation and tolerization with rFVIIIFc, as well as studies in joint and bone health, to elucidate the potential benefits of rFVIIIFc in haemophilia A beyond the extension of factor VIII half‐life.
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Affiliation(s)
- Shannon L Meeks
- Aflac Cancer Center and Blood Disorders Center at Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
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14
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Zerra PE, Arthur CM, Chonat S, Maier CL, Mener A, Shin S, Allen JWL, Baldwin WH, Cox C, Verkerke H, Jajosky RP, Tormey CA, Meeks SL, Stowell SR. Fc Gamma Receptors and Complement Component 3 Facilitate Anti-fVIII Antibody Formation. Front Immunol 2020; 11:905. [PMID: 32582142 PMCID: PMC7295897 DOI: 10.3389/fimmu.2020.00905] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/20/2020] [Indexed: 01/02/2023] Open
Abstract
Anti-factor VIII (fVIII) alloantibodies, which can develop in patients with hemophilia A, limit the therapeutic options and increase morbidity and mortality of these patients. However, the factors that influence anti-fVIII antibody development remain incompletely understood. Recent studies suggest that Fc gamma receptors (FcγRs) may facilitate recognition and uptake of fVIII by recently developed or pre-existing naturally occurring anti-fVIII antibodies, providing a mechanism whereby the immune system may recognize fVIII following infusion. However, the role of FcγRs in anti-fVIII antibody formation remains unknown. In order to define the influence of FcγRs on the development of anti-fVIII antibodies, fVIII was injected into WT or FcγR knockout recipients, followed by evaluation of anti-fVIII antibodies. Anti-fVIII antibodies were readily observed following fVIII injection into FcγR knockouts, with similar anti-fVIII antibody levels occurring in FcγR knockouts as detected in WT mice injected in parallel. As antibodies can also fix complement, providing a potential mechanism whereby anti-fVIII antibodies may influence anti-fVIII antibody formation independent of FcγRs, fVIII was also injected into complement component 3 (C3) knockout recipients in parallel. Similar to FcγR knockouts, C3 knockout recipients developed a robust response to fVIII, which was likewise similar to that observed in WT recipients. As FcγRs or C3 may compensate for each other in recipients only deficient in FcγRs or C3 alone, we generated mice deficient in both FcγRs and C3 to test for potential antibody effector redundancy in anti-fVIII antibody formation. Infusion of fVIII into FcγRs and C3 (FcγR × C3) double knockouts likewise induced anti-fVIII antibodies. However, unlike individual knockouts, anti-fVIII antibodies in FcγRs × C3 knockouts were initially lower than WT recipients, although anti-fVIII antibodies increased to WT levels following additional fVIII exposure. In contrast, infusion of RBCs expressing distinct alloantigens into FcγRs, C3 or FcγR × C3 knockout recipients either failed to change anti-RBC levels when compared to WT recipients or actually increased antibody responses, depending on the target antigen. Taken together, these results suggest FcγRs and C3 can differentially impact antibody formation following exposure to distinct alloantigens and that FcγRs and C3 work in concert to facilitate early anti-fVIII antibody formation.
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Affiliation(s)
- Patricia E Zerra
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States.,Aflac Cancer and Blood Disorders Center at Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Connie M Arthur
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States
| | - Satheesh Chonat
- Aflac Cancer and Blood Disorders Center at Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Cheryl L Maier
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States
| | - Amanda Mener
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States
| | - Sooncheon Shin
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States
| | - Jerry William L Allen
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States
| | - W Hunter Baldwin
- Aflac Cancer and Blood Disorders Center at Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Courtney Cox
- Aflac Cancer and Blood Disorders Center at Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Hans Verkerke
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States
| | - Ryan P Jajosky
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States
| | - Christopher A Tormey
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, United States.,Pathology and Laboratory Medicine Service, VA Conneciticut Healthcare System, West Haven, CT, United States
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center at Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Sean R Stowell
- Department of Pathology and Laboratory Medicine, Center for Transfusion Medicine and Cellular Therapies, Emory University School of Medicine, Atlanta, GA, United States
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15
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Meeks SL, Leissinger CA. The evolution of factor VIIa in the treatment of bleeding in haemophilia with inhibitors. Haemophilia 2019; 25:911-918. [PMID: 31489759 PMCID: PMC6899648 DOI: 10.1111/hae.13845] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 08/07/2019] [Accepted: 08/19/2019] [Indexed: 01/19/2023]
Abstract
The use of activated factor VII (FVIIa) for the treatment of bleeding events in haemophilia patients with inhibitors was first reported over 30 years ago. Since then clinical trials, registries, case series, real‐world experience and an understanding of its mechanism of action have transformed what was originally a scientific curiosity into one of the major treatments for inhibitor patients, with innovative therapeutic regimens, dose optimization and individualized care now widely practiced. Given current understanding and use, it might be easy to forget the years of clinical research that led up to this point; in this review, we lay out changes based on broad eras of rFVIIa use. These eras cover the original uncertainty associated with dosing, efficacy and safety; the transformation of care ushered in with its widespread use; and the optimization and individualization of patient care and the importance of specialized support provided by haemophilia treatment centres. Today with the introduction of novel prophylactic agents such as emicizumab, we once again find ourselves dealing with the uncertainties of how best to utilize rFVIIa and newer investigational variants such as marzeptacog alfa and eptacog beta; we hope that the experiences of the past three decades will serve as a guide for this new era of care.
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Affiliation(s)
- Shannon L Meeks
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center at Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, USA
| | - Cindy A Leissinger
- Section of Hematology/Oncology, Tulane University School of Medicine, New Orleans, LA, USA
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16
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Batsuli G, Zimowski KL, Tickle K, Meeks SL, Sidonio RF. Immune tolerance induction in paediatric patients with haemophilia A and inhibitors receiving emicizumab prophylaxis. Haemophilia 2019; 25:789-796. [DOI: 10.1111/hae.13819] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/17/2019] [Accepted: 06/17/2019] [Indexed: 12/23/2022]
Affiliation(s)
- Glaivy Batsuli
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Department of Pediatrics Emory University Atlanta Georgia
| | - Karen L. Zimowski
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Department of Pediatrics Emory University Atlanta Georgia
| | - Kelly Tickle
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta Atlanta Georgia
| | - Shannon L. Meeks
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Department of Pediatrics Emory University Atlanta Georgia
| | - Robert F. Sidonio
- Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, Department of Pediatrics Emory University Atlanta Georgia
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17
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Meeks SL, Herzog RW. The national blueprint for future basic and translational research to understand factor VIII immunogenicity: NHLBI State of the Science Workshop on factor VIII inhibitors. Haemophilia 2019; 25:595-602. [DOI: 10.1111/hae.13740] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/29/2019] [Accepted: 02/22/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Shannon L. Meeks
- Aflac Cancer and Blood Disorders Service; Emory University; Atlanta Georgia
| | - Roland W. Herzog
- Herman B Wells Center for Pediatric Research; Indiana University; Indianapolis Indiana
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18
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Batsuli G, Ito J, Mercer R, Baldwin WH, Cox C, Parker ET, Healey JF, Lollar P, Meeks SL. Anti-C1 domain antibodies that accelerate factor VIII clearance contribute to antibody pathogenicity in a murine hemophilia A model. J Thromb Haemost 2018; 16:1779-1788. [PMID: 29981270 PMCID: PMC6123829 DOI: 10.1111/jth.14233] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Indexed: 01/06/2023]
Abstract
Essentials Inhibitor formation remains a challenging complication of hemophilia A care. The Bethesda assay is the primary method used for determining bleeding risk and management. Antibodies that block factor VIII binding to von Willebrand factor can increase FVIII clearance. Antibodies that increase clearance contribute to antibody pathogenicity. SUMMARY Background The development of neutralizing anti-factor VIII (FVIII) antibodies remains a challenging complication of modern hemophilia A care. In vitro assays are the primary method used for quantifying inhibitor titers, predicting bleeding risk, and determining bleeding management. However, other mechanisms of inhibition are not accounted for in these assays, which may result in discrepancies between the inhibitor titer and clinical bleeding symptoms. Objectives To evaluate FVIII clearance in vivo as a potential mechanism for antibody pathogenicity and to determine whether increased FVIII dosing regimens correct the associated bleeding phenotype. Methods FVIII-/- or FVIII-/- /von Willebrand factor (VWF)-/- mice were infused with anti-FVIII mAbs directed against the FVIII C1, C2 or A2 domains, followed by infusion of FVIII. Blood loss via the tail snip bleeding model, FVIII activity and FVIII antigen levels were subsequently measured. Results Pathogenic anti-C1 mAbs that compete with VWF for FVIII binding increased the clearance of FVIII-mAb complexes in FVIII-/- mice but not in FVIII-/- /VWF-/- mice. Additionally, pathogenic anti-C2 mAbs that inhibit FVIII binding to VWF increased FVIII clearance in FVIII-/- mice. Anti-C1, anti-C2 and anti-A2 mAbs that do not inhibit VWF binding did not accelerate FVIII clearance. Infusion of increased doses of FVIII in the presence of anti-C1 mAbs partially corrected blood loss in FVIII-/- mice. Conclusions A subset of antibodies that inhibit VWF binding to FVIII increase the clearance of FVIII-mAb complexes, which contributes to antibody pathogenicity. This may explain differences in the bleeding phenotype observed despite factor replacement in some patients with hemophilia A and low-titer inhibitors.
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MESH Headings
- Animals
- Antibodies, Heterophile/administration & dosage
- Antibodies, Heterophile/immunology
- Antibodies, Heterophile/toxicity
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/toxicity
- Antibodies, Neutralizing/administration & dosage
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/toxicity
- Epitopes/immunology
- Factor VIII/antagonists & inhibitors
- Factor VIII/immunology
- Factor VIII/pharmacokinetics
- Hemophilia A/drug therapy
- Hemophilia A/immunology
- Hemorrhage/etiology
- Inhibitory Concentration 50
- Mice
- Mice, 129 Strain
- Mice, Inbred C57BL
- Models, Animal
- Phenotype
- Protein Domains
- von Willebrand Diseases
- von Willebrand Factor/metabolism
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Affiliation(s)
- G Batsuli
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - J Ito
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - R Mercer
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - W H Baldwin
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - C Cox
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - E T Parker
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - J F Healey
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - P Lollar
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
| | - S L Meeks
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta, Emory University, Atlanta, GA, USA
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Hansen CE, Myers DR, Baldwin WH, Sakurai Y, Meeks SL, Lyon LA, Lam WA. Platelet-Microcapsule Hybrids Leverage Contractile Force for Targeted Delivery of Hemostatic Agents. ACS Nano 2017; 11:5579-5589. [PMID: 28541681 DOI: 10.1021/acsnano.7b00929] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report a cell-mediated, targeted drug delivery system utilizing polyelectrolyte multilayer capsules that hybridize with the patient's own platelets upon intravenous administration. The hybridized platelets function as the sensor and actuator for targeted drug delivery and controlled release in our system. These capsules are biochemically and mechanically tuned to enable platelet adhesion and capsule rupture upon platelet activation and contraction, enabling the targeted and controlled "burst" release of an encapsulated biotherapeutic. As platelets are the "first responders" in the blood clot formation process, this platelet-hybridized system is ideal for the targeted delivery of clot-augmenting biotherapeutics wherein immediate therapeutic efficacy is required. As proof-of-concept, we tailored this system to deliver the pro-clotting biotherapeutic factor VIII for hemophilia A patients that have developed inhibitory antifactor VIII antibodies. The polyelectrolyte multilayer capsules physically shield the encapsulated factor VIII from the patient's inhibitors during circulation, preserving its bioactivity until it is delivered at the target site via platelet contractile force. Using an in vitro microfluidic vascular injury model with factor VIII-inhibited blood, we demonstrate a 3.8× increase in induced fibrin formation using capsules loaded with factor VIII at a concentration an order of magnitude lower than that used in systemic delivery. We further demonstrate that clot formation occurs 18 min faster when factor VIII loaded capsules are used compared to systemic delivery at the same concentration. Because platelets are integral in the pathophysiology of thrombotic disorders, cancer, and innate immunity, this paradigm-shifting smart drug delivery system can be similarly applied to these diseases.
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Affiliation(s)
- Caroline E Hansen
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine , Atlanta, Georgia 30322, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States
| | - David R Myers
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine , Atlanta, Georgia 30322, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States
| | - W Hunter Baldwin
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine , Atlanta, Georgia 30322, United States
| | - Yumiko Sakurai
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine , Atlanta, Georgia 30322, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine , Atlanta, Georgia 30322, United States
| | - L Andrew Lyon
- Schmid College of Science and Technology, Chapman University , Orange, California 92866, United States
| | - Wilbur A Lam
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta/Emory University School of Medicine , Atlanta, Georgia 30322, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States
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Abstract
INTRODUCTION Haemophilia A is an X-linked bleeding disorder characterized by a deficiency of coagulation protein factor VIII (FVIII). A challenging complication of therapeutic FVIII infusions is the formation of neutralizing alloantibodies against the FVIII protein defined as inhibitors. The development of FVIII inhibitors drastically alters the quality of life of the patients and is associated with tremendous increases in morbidity as well as treatment costs. AIM Current clinical immune tolerance induction protocols to reverse inhibitors are lengthy, costly and not effective in all patients. Prophylactic protocols to prevent inhibitor formation have not yet been developed in the clinical setting. However, there has been ample progress towards this goal in recent years in preclinical studies using animal models of haemophilia. METHODS Here, we review the mechanisms that lead to inhibitor formation against FVIII and two promising new strategies for antigen-specific tolerance induction. RESULTS CD4+ T cells play an important role in the FVIII-specific B cell response. Immune tolerance can be induced based on transplacental delivery of FVIII domains fused to Fc or on oral delivery of leaf cells from chloroplast transgenic crop plants. CONCLUSIONS Recent literature suggests that prophylactic tolerance induction protocols for FVIII may be feasible in haemophilia A patients.
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Affiliation(s)
- G Batsuli
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University, Atlanta, GA, USA
| | - S L Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta/Emory University, Atlanta, GA, USA
| | - R W Herzog
- Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - S Lacroix-Desmazes
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France
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Meeks SL, Batsuli G. Hemophilia and inhibitors: current treatment options and potential new therapeutic approaches. Hematology Am Soc Hematol Educ Program 2016; 2016:657-662. [PMID: 27913543 PMCID: PMC6142469 DOI: 10.1182/asheducation-2016.1.657] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The immune response to infused factor concentrates remains a major source of morbidity and mortality in the treatment of patients with hemophilia A and B. This review focuses on current treatment options and novel therapies currently in clinical trials. After a brief review of immune tolerance regimens, the focus of the discussion is on preventing bleeding in patients with hemophilia and inhibitors. Recombinant factor VIIa and activated prothrombin complex concentrates are the mainstays in treating bleeds in patients with inhibitors. Both agents have been shown to reduce bleeding episodes to a similar degree when infused prophylactically; however, individual patients may respond better to one agent over the other at any given time. The international immune tolerance trial revealed that a high-dose factor VIII regimen provided significantly better bleeding protection than the low-dose regimen. Given the high cost of treatment and the potential for a high-dose immune tolerance regimen to prevent bleeding in some patients, we discuss how we treat patients to maximize the prevention of bleeds while minimizing cost. Novel approaches to treatment of these patients are in development. These include agents that mimic factor VIII or augment thrombin generation by bypassing the inhibitor, as well as agents that inhibit the natural anticoagulants.
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Affiliation(s)
- Shannon L Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA
| | - Glaivy Batsuli
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA
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Chao BN, Baldwin WH, Healey JF, Parker ET, Shafer-Weaver K, Cox C, Jiang P, Kanellopoulou C, Lollar P, Meeks SL, Lenardo MJ. Characterization of a genetically engineered mouse model of hemophilia A with complete deletion of the F8 gene. J Thromb Haemost 2016; 14:346-55. [PMID: 26588198 PMCID: PMC4755856 DOI: 10.1111/jth.13202] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Indexed: 12/27/2022]
Abstract
UNLABELLED ESSENTIALS: Anti-factor VIII (FVIII) inhibitory antibody formation is a severe complication in hemophilia A therapy. We genetically engineered and characterized a mouse model with complete deletion of the F8 coding region. F8(TKO) mice exhibit severe hemophilia, express no detectable F8 mRNA, and produce FVIII inhibitors. The defined background and lack of FVIII in F8(TKO) mice will aid in studying FVIII inhibitor formation. BACKGROUND The most important complication in hemophilia A treatment is the development of inhibitory anti-Factor VIII (FVIII) antibodies in patients after FVIII therapy. Patients with severe hemophilia who express no endogenous FVIII (i.e. cross-reacting material, CRM) have the greatest incidence of inhibitor formation. However, current mouse models of severe hemophilia A produce low levels of truncated FVIII. The lack of a corresponding mouse model hampers the study of inhibitor formation in the complete absence of FVIII protein. OBJECTIVES We aimed to generate and characterize a novel mouse model of severe hemophilia A (designated the F8(TKO) strain) lacking the complete coding sequence of F8 and any FVIII CRM. METHODS Mice were created on a C57BL/6 background using Cre-Lox recombination and characterized using in vivo bleeding assays, measurement of FVIII activity by coagulation and chromogenic assays, and anti-FVIII antibody production using ELISA. RESULTS All F8 exonic coding regions were deleted from the genome and no F8 mRNA was detected in F8(TKO) mice. The bleeding phenotype of F8(TKO) mice was comparable to E16 mice by measurements of factor activity and tail snip assay. Similar levels of anti-FVIII antibody titers after recombinant FVIII injections were observed between F8(TKO) and E16 mice. CONCLUSIONS We describe a new C57BL/6 mouse model for severe hemophilia A patients lacking CRM. These mice can be directly bred to the many C57BL/6 strains of genetically engineered mice, which is valuable for studying the impact of a wide variety of genes on FVIII inhibitor formation on a defined genetic background.
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Affiliation(s)
- Brittany N. Chao
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, MD
| | - Wallace H. Baldwin
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta; the Department of Pediatrics, Emory University, Atlanta, GA
| | - John F. Healey
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta; the Department of Pediatrics, Emory University, Atlanta, GA
| | - Ernest T. Parker
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta; the Department of Pediatrics, Emory University, Atlanta, GA
| | - Kimberly Shafer-Weaver
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, MD
| | - Courtney Cox
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta; the Department of Pediatrics, Emory University, Atlanta, GA
| | - Ping Jiang
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, MD
| | - Chrysi Kanellopoulou
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, MD
| | - Pete Lollar
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta; the Department of Pediatrics, Emory University, Atlanta, GA
| | - Shannon L. Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta; the Department of Pediatrics, Emory University, Atlanta, GA
| | - Michael J. Lenardo
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, MD
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Abstract
Treatment of patients with hemophilia A and B has undergone significant advances during the past 2 decades. However, despite these advances, the development of antibodies that inhibit the function of infused clotting factor remains a major challenge and is considered the most significant complication of hemophilia treatment. This chapter reviews current tools available for the care of patients with inhibitors and highlights areas where progress is imminent or strongly needed. For management of bleeding, bypassing agents remain the mainstay of therapy. Recombinant factor VIIa and activated prothrombin complex concentrates are similarly effective in populations of patients with hemophilia and inhibitors; however, individuals may show a better response to one agent over another. Recent studies have shown that prophylaxis with bypassing agents can reduce bleeding episodes by ∼50%-80%. The prophylactic use of bypassing agents is an important tool to reduce morbidity in patients before they undergo immune tolerance induction (ITI) and in those with persistent high titer inhibitors, but cost and lack of convenience remain barriers. Because of the significant burden that inhibitors add to the individual patient and the health care system, inhibitor eradication should be pursued in as many patients as possible. ITI is an effective tool, particularly in patients with severe hemophilia A and good risk profiles, and leads to a return to a normal factor VIII response in ∼60% of patients. However, for the group of patients who fail to respond to ITI or have hemophilia B, new and improved tools are needed.
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Affiliation(s)
- Christine L Kempton
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, and Department of Hematology and Medical Oncology, Emory University, Atlanta, GA
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, and
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24
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Tran DQ, Harvey RD, Meeks SL, Chapman R, Kempton CL. Use of factor VIII after inhibitor clearance in patients with moderate haemophilia A: a case series. Haemophilia 2014; 20:e344-6. [PMID: 24750497 DOI: 10.1111/hae.12452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2014] [Indexed: 11/29/2022]
Affiliation(s)
- D Q Tran
- Department of Hematology and Medical Oncology, Emory University, School of Medicine, Atlanta, GA, USA
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25
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Sevy AM, Healey JF, Deng W, Spiegel PC, Meeks SL, Li R. Epitope mapping of inhibitory antibodies targeting the C2 domain of coagulation factor VIII by hydrogen-deuterium exchange mass spectrometry. J Thromb Haemost 2013; 11:2128-36. [PMID: 24152306 PMCID: PMC3947443 DOI: 10.1111/jth.12433] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Indexed: 01/18/2023]
Abstract
BACKGROUND The development of anti-factor VIII antibodies (inhibitors) is a significant complication in the management of patients with hemophilia A, leading to significant increases in morbidity and treatment cost. Using a panel of mAbs against different epitopes on FVIII, we have recently shown that epitope specificity, inhibitor kinetics and time to maximum inhibition are more important than inhibitor titer in predicting responses to FVIII and the combination of FVIII and recombinant FVIIa. In particular, a subset of high-titer inhibitors responded to high-dose FVIII, which would not be predicted on the basis of their inhibitor titer alone. Thus, the ability to quickly map the epitope spectrum of patient plasma with a clinically feasible assay may fundamentally change how clinicians approach the treatment of high-titer inhibitor patients. OBJECTIVES To map the epitopes of anti-FVIII mAbs, three of which are classic inhibitors and one of which is a non-classic inhibitor, by the use of hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS). METHODS The binding epitopes of four mAbs targeting the FVIII C2 domain were mapped with HDX-MS. RESULTS The epitopes determined with HDX-MS are consistent with those obtained earlier through structural characterization and antibody competition assays. In addition, classic and non-classic inhibitor epitopes could be distinguished by the use of a limited subset of C2 domain-derived peptic fragments. CONCLUSION Our results demonstrate the effectiveness and robustness of the HDX-MS method for epitope mapping, and suggest a potential role of rapid mapping of FVIII inhibitor epitopes in facilitating individualized treatment of inhibitor patients.
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Affiliation(s)
- Alexander M. Sevy
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - John F. Healey
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - Wei Deng
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - P. Clint Spiegel
- Department of Chemistry, Western Washington University, Bellingham, WA, USA
| | - Shannon L. Meeks
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA
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26
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Walter JD, Werther RA, Polozova MS, Pohlman J, Healey JF, Meeks SL, Lollar P, Spiegel PC. Characterization and solution structure of the factor VIII C2 domain in a ternary complex with classical and non-classical inhibitor antibodies. J Biol Chem 2013; 288:9905-9914. [PMID: 23417672 DOI: 10.1074/jbc.m112.424564] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The most significant complication for patients with severe cases of congenital or acquired hemophilia A is the development of inhibitor antibodies against coagulation factor VIII (fVIII). The C2 domain of fVIII is a significant antigenic target of anti-fVIII antibodies. Here, we have utilized small angle x-ray scattering (SAXS) and biochemical techniques to characterize interactions between two different classes of anti-C2 domain inhibitor antibodies and the isolated C2 domain. Multiple assays indicated that antibodies 3E6 and G99 bind independently to the fVIII C2 domain and can form a stable ternary complex. SAXS-derived numerical estimates of dimensional parameters for all studied complexes agree with the proportions of the constituent proteins. Ab initio modeling of the SAXS data results in a long kinked structure of the ternary complex, showing an angle centered at the C2 domain of ∼130°. Guided by biochemical data, rigid body modeling of subunits into the molecular envelope of the ternary complex suggests that antibody 3E6 recognizes a C2 domain epitope consisting of the Arg(2209)-Ser(2216) and Leu(2178)-Asp(2187) loops. In contrast, antibody G99 recognizes the C2 domain primarily through the Pro(2221)-Trp(2229) loop. These two epitopes are on opposing sides of the fVIII C2 domain, are consistent with the solvent accessibility in the context of the entire fVIII molecule, and provide further structural detail regarding the pathogenic immune response to fVIII.
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Affiliation(s)
- Justin D Walter
- Department of Chemistry, Western Washington University, Bellingham, Washington 98225
| | - Rachel A Werther
- Department of Chemistry, Western Washington University, Bellingham, Washington 98225
| | - Maria S Polozova
- Department of Chemistry, Western Washington University, Bellingham, Washington 98225
| | - Julie Pohlman
- Department of Chemistry, Western Washington University, Bellingham, Washington 98225
| | - John F Healey
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, Atlanta, Georgia 30322
| | - Shannon L Meeks
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, Atlanta, Georgia 30322
| | - Pete Lollar
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University, Atlanta, Georgia 30322
| | - P Clint Spiegel
- Department of Chemistry, Western Washington University, Bellingham, Washington 98225.
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Paschal RD, Meeks SL, Neff AT. Development of factor VIII inhibitors in two patients with moderate haemophilia A. Haemophilia 2012; 19:e55-7. [PMID: 23171275 DOI: 10.1111/hae.12057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2012] [Indexed: 11/30/2022]
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Doshi BS, Gangadharan B, Doering CB, Meeks SL. Potentiation of thrombin generation in hemophilia A plasma by coagulation factor VIII and characterization of antibody-specific inhibition. PLoS One 2012; 7:e48172. [PMID: 23144741 PMCID: PMC3483154 DOI: 10.1371/journal.pone.0048172] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 09/20/2012] [Indexed: 11/18/2022] Open
Abstract
Development of inhibitory antibodies to coagulation factor VIII (fVIII) is the primary obstacle to the treatment of hemophilia A in the developed world. This adverse reaction occurs in 20-30% of persons with severe hemophilia A treated with fVIII-replacement products and is characterized by the development of a humoral and neutralizing immune response to fVIII. Patients with inhibitory anti-fVIII antibodies are treated with bypassing agents including recombinant factor VIIa (rfVIIa). However, some patients display poor hemostatic response to bypass therapy and improved treatment options are needed. Recently, we demonstrated that fVIII inhibitors display widely variable kinetics of inhibition that correlate with their respective target epitopes. Thus, it was hypothesized that for antibodies that display slow rates of inhibition, supplementation of rfVIIa with fVIII would result in improved thrombin generation and be predictive of clinical responses to this novel treatment regimen. In order to test this hypothesis, 10 murine monoclonal antibodies (MAbs) with non-overlapping epitopes spanning fVIII, differential inhibition titers, and inhibition kinetics were studied using a thrombin generation assay. Of the 3 MAbs with high inhibitory titers, only the one with fast and complete (classically defined as "type I") kinetics displayed significant inhibition of thrombin generation with no improvement upon supplementation of rfVIIa with fVIII. The other two MAbs that displayed incomplete (classically defined as "type II") inhibition did not suppress the potentiation of thrombin generation by fVIII. All antibodies that did not completely inhibit fVIII activity demonstrated potentiation of thrombin generation by the addition of fVIII as compared to rfVIIa alone. In conclusion, fVIII alone or in combination with rfVIIa corrects the thrombin generation defect produced by the majority of anti-fVIII MAbs better than single agent rfVIIa. Therefore, combined fVIII/rfVIIa therapy may provide better hemostatic control than current therapy in some patients with anti-fVIII inhibitors.
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Affiliation(s)
- Bhavya S. Doshi
- Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Bagirath Gangadharan
- Aflac Cancer Center and Blood Disorders Service, Children’s Healthcare of Atlanta and Emory University, Atlanta, Georgia, United States of America
| | - Christopher B. Doering
- Aflac Cancer Center and Blood Disorders Service, Children’s Healthcare of Atlanta and Emory University, Atlanta, Georgia, United States of America
| | - Shannon L. Meeks
- Aflac Cancer Center and Blood Disorders Service, Children’s Healthcare of Atlanta and Emory University, Atlanta, Georgia, United States of America
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Santhanam AP, Min Y, Neelakkantan H, Papp N, Meeks SL, Kupelian PA. A multi-GPU real-time dose simulation software framework for lung radiotherapy. Int J Comput Assist Radiol Surg 2012; 7:705-19. [PMID: 22539007 DOI: 10.1007/s11548-012-0672-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 01/31/2012] [Indexed: 12/25/2022]
Abstract
PURPOSE Medical simulation frameworks facilitate both the preoperative and postoperative analysis of the patient's pathophysical condition. Of particular importance is the simulation of radiation dose delivery for real-time radiotherapy monitoring and retrospective analyses of the patient's treatment. METHODS In this paper, a software framework tailored for the development of simulation-based real-time radiation dose monitoring medical applications is discussed. A multi-GPU-based computational framework coupled with inter-process communication methods is introduced for simulating the radiation dose delivery on a deformable 3D volumetric lung model and its real-time visualization. The model deformation and the corresponding dose calculation are allocated among the GPUs in a task-specific manner and is performed in a pipelined manner. Radiation dose calculations are computed on two different GPU hardware architectures. The integration of this computational framework with a front-end software layer and back-end patient database repository is also discussed. RESULTS Real-time simulation of the dose delivered is achieved at once every 120 ms using the proposed framework. With a linear increase in the number of GPU cores, the computational time of the simulation was linearly decreased. The inter-process communication time also improved with an increase in the hardware memory. Variations in the delivered dose and computational speedup for variations in the data dimensions are investigated using D70 and D90 as well as gEUD as metrics for a set of 14 patients. Computational speed-up increased with an increase in the beam dimensions when compared with a CPU-based commercial software while the error in the dose calculation was <1%. CONCLUSION Our analyses show that the framework applied to deformable lung model-based radiotherapy is an effective tool for performing both real-time and retrospective analyses.
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Pukala J, Meeks SL, Bova FJ, Langen KM. The effect of temporal HU variations on the uncertainty of dose recalculations performed on MVCT images. Phys Med Biol 2011; 56:7829-41. [PMID: 22113540 DOI: 10.1088/0031-9155/56/24/010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Over the course of radiation therapy, a patient's anatomy may change substantially. The relatively recent addition of frequent in-room imaging to assist with patient localization has provided a database of images that may be used to recalculate dose distributions for adaptive radiotherapy purposes. The TomoTherapy Hi-Art II unit (Accuray Inc., Sunnyvale, CA, USA) uses a helical scanning geometry and a megavoltage (MV) beam to acquire volumetric patient images. This study evaluated the uncertainty of dose calculations performed on megavoltage CT (MVCT) images as a function of temporal Hounsfield Unit (HU) variations observed in the imaging system over three years on two machines. A baseline error between dose calculations performed on kVCT and MVCT images was established using a series of phantoms. This baseline error ranged from -1.4% to 0.6%. Materials of differing densities were imaged and MVCT numbers were measured periodically. The MVCT number of solid water varied from 5 to 103 HU and consistently increased prior to target replacement. Finally, the dosimetric uncertainty of the temporal HU variation was assessed using MVCT images of typical head and neck, lung and prostate cancer patients. Worst-case MVCT recalculation errors could approach 5%, 7% and 10% for the head and neck, lung and prostate images, respectively. However, if a tolerance of ±30 HU were maintained for the MVCT number of solid water, dosimetric errors were limited to ±2.5%, ±3% and ±4%, respectively.
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Affiliation(s)
- J Pukala
- Department of Radiation Oncology, M D Anderson Cancer Center Orlando, Orlando, FL 32806, USA.
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31
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Zeidan OA, Sriprisan SI, Lopatiuk-Tirpak O, Kupelian PA, Meeks SL, Hsi WC, Li Z, Palta JR, Maryanski MJ. Dosimetric evaluation of a novel polymer gel dosimeter for proton therapy. Med Phys 2010; 37:2145-52. [PMID: 20527548 DOI: 10.1118/1.3388869] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
PURPOSE The aim of this study is to evaluate the dosimetric performance of a newly developed proton-sensitive polymer gel formulation for proton therapy dosimetry. METHODS Using passive scattered modulated and nonmodulated proton beams, the dose response of the gel was assessed. A next-generation optical CT scanner is used as the readout mechanism of the radiation-induced absorbance in the gel medium. Comparison of relative dose profiles in the gel to ion chamber profiles in water is performed. A simple and easily reproducible calibration protocol is established for routine gel batch calibrations. Relative stopping power ratio measurement of the gel medium was performed to ensure accurate water-equivalent depth dose scaling. Measured dose distributions in the gel were compared to treatment planning system for benchmark irradiations and quality of agreement is assessed using clinically relevant gamma index criteria. RESULTS The dosimetric response of the gel was mapped up to 600 cGy using an electron-based calibration technique. Excellent dosimetric agreement is observed between ion chamber data and gel. The most notable result of this work is the fact that this gel has no observed dose quenching in the Bragg peak region. Quantitative dose distribution comparisons to treatment planning system calculations show that most (> 97%) of the gel dose maps pass the 3%/3 mm gamma criterion. CONCLUSIONS This study shows that the new proton-sensitive gel dosimeter is capable of reproducing ion chamber dose data for modulated and nonmodulated Bragg peak beams with different clinical beam energies. The findings suggest that the gel dosimeter can be used as QA tool for millimeter range verification of proton beam deliveries in the dosimeter medium.
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Affiliation(s)
- O A Zeidan
- M. D. Anderson Cancer Center Orlando, Orlando, Florida 32806, USA.
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Abstract
OBJECTIVE The pathogenicity of anti-human factor (F) VIII monoclonal antibodies (MAbs) was tested in a murine bleeding model. METHODS MAbs were injected into the tail veins of hemophilia A mice to a peak plasma concentration of 60 nm, followed by injection of human B domain-deleted FVIII at 180 U kg(-1), producing peak plasma concentrations of approximately 2 nm. At 2 h, blood loss following a 4-mm tail snip was measured. The following MAbs were tested: (i) 4A4, a type I anti-A2 FVIII inhibitor, (ii) I54 and 1B5, classical type I anti-C2 inhibitors, (iii) 2-77 and B45, non-classical type II anti-C2 inhibitors, and (iv) 2-117, a non-classical anti-C2 MAb with inhibitory activity less than 0.4 Bethesda Units per mg IgG. RESULTS All MAbs except 2-117 produced similar amounts of blood loss that were significantly greater than control mice injected with FVIII alone. Increasing the dose of FVIII to 360 U kg(-1) overcame the bleeding diathesis produced by the type II MAbs 2-77 and B45, but not the type I antibodies, 4A4, I54, and 1B5. These results were consistent with the in vitro Bethesda assay in which 4A4 completely inhibited both 1 U mL(-1) and 3 U mL(-1) FVIII, while there was 40% residual activity at saturating concentrations of 2-77 at either concentration of FVIII. CONCLUSIONS For patients with an inhibitor response dominated by non-classical anti-C2 antibodies both the in vivo and in vitro results suggest that treatment with high-dose FVIII rather than bypassing agents may be warranted.
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Affiliation(s)
- S L Meeks
- Department of Pediatrics, Aflac Cancer Center and Blood Disorders Service, Children's Healthcare of Atlanta, Emory University, Atlanta, GA 30322, USA
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Meeks SL, Healey JF, Parker ET, Barrow RT, Lollar P. Antihuman factor VIII C2 domain antibodies in hemophilia A mice recognize a functionally complex continuous spectrum of epitopes dominated by inhibitors of factor VIII activation. Blood 2007; 110:4234-42. [PMID: 17848617 PMCID: PMC2234776 DOI: 10.1182/blood-2007-06-096842] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The diversity of factor VIII (fVIII) C2 domain antibody epitopes was investigated by competition enzyme-linked immunosorbent assay (ELISA) using a panel of 56 antibodies. The overlap patterns produced 5 groups of monoclonal antibodies (MAbs), designated A, AB, B, BC, and C, and yielded a set of 18 distinct epitopes. Group-specific loss of antigenicity was associated with mutations at the Met2199/Phe2200 phospholipid binding beta-hairpin (group AB MAbs) and at Lys2227 (group BC MAbs), which allowed orientation of the epitope structure as a continuum that covers one face of the C2 beta-sandwich. MAbs from groups A, AB, and B inhibit the binding of fVIIIa to phospholipid membranes. Group BC was the most common group and displayed the highest specific fVIII inhibitor activities. MAbs in this group are type II inhibitors that inhibit the activation of fVIII by either thrombin or factor Xa and poorly inhibit the binding of fVIII to phospholipid membranes or von Willebrand factor (VWF). Group BC MAbs are epitopically and mechanistically distinct from the extensively studied group C MAb, ESH8. These results reveal the structural and functional complexity of the anti-C2 domain antibody response and indicate that interference with fVIII activation is a major attribute of the inhibitor landscape.
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Affiliation(s)
- Shannon L Meeks
- Aflac Cancer Center and Blood Disorders Service, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University, Atlanta, GA, USA
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Abstract
PURPOSE OF REVIEW To discuss the advantages and disadvantages of the albumin-free recombinant factor VIII concentrates in the treatment of hemophilia A. RECENT FINDINGS The third-generation recombinant factor VIII product Advate has been found to be safe and effective in treating bleeding associated with hemophilia A. SUMMARY Multiple issues must be considered when selecting a factor VIII concentrate for patients with hemophilia A including efficacy, availability, risk of transmission of infectious agents, risk of inhibitor development and cost. Third-generation recombinant factor VIII concentrates have been shown to be safe and effective. A theoretical improvement in risk of infectious agent transmission has been achieved by production of the products without human or animal plasma proteins. Controversy exists, however, with regard to a higher risk of inhibitor development with recombinant products. The higher cost of Advate can also potentially play a role in product choice. Overall every patient and their family must be presented with the advantages and disadvantages of all factor VIII concentrates, and be allowed to make an informed decision about which product to use for treatment.
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Affiliation(s)
- Shannon L Meeks
- Aflac Cancer Center and Blood Disorders Service, Emory University/Children's Healthcare of Atlanta, USA.
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Langen KM, Meeks SL, Poole DO, Wagner TH, Willoughby TR, Zeidan OA, Kupelian PA, Ruchala KJ, Olivera GH. Evaluation of a diode array for QA measurements on a helical tomotherapy unit. Med Phys 2005; 32:3424-30. [PMID: 16370429 DOI: 10.1118/1.2089547] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A helical tomotherapy system is used in our clinic to deliver intensity-modulated radiation therapy (IMRT) treatments. Since this machine is designed to deliver IMRT treatments, the traditional field flatness requirements are no longer applicable. This allows the unit to operate without a field flatness filter and consequently the 400 mm wide fan beam is highly inhomogeneous in intensity. The shape of this beam profile is mapped during machine commissioning and for quality assurance purposes the shape of the beam profile needs to be monitored. The use of a commercial diode array for quality assurance measurements is investigated. Central axis beam profiles were acquired at different depths using solid water built-up material. These profiles were compared with ion chamber scans taken in a water tank to test the accuracy of the diode array measurements. The sensitivity of the diode array to variations in the beam profile was checked. Over a seven week period, beam profiles were repeatedly measured. The observed variations are compared with those observed with an on-board beam profile monitor. The diode measurements were in agreement with the ion chamber scans. In the high dose, low gradient region the average ratio between the diode and ion chamber readings was 1.000 +/- 0.005 (+/- 1 standard deviation). In the penumbra region the agreement was poorer but all diodes passed the distance to agreement (DTA) requirement of 2 mm. The trend in the beam profile variations that was measured with the diode array device was in agreement with the on-board monitor. While the calculated amount of variation differs between the devices, both were sensitive to subtle variations in the beam profile. The diode array is a valuable tool to quickly and accurately monitor the beam profile on a helical tomotherapy unit.
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Affiliation(s)
- K M Langen
- Department of Radiation Oncology, M.D. Anderson Cancer Center Orlando, Orlando, Florida, USA.
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Langen KM, Meeks SL, Poole DO, Wagner TH, Willoughby TR, Kupelian PA, Ruchala KJ, Haimerl J, Olivera GH. The use of megavoltage CT (MVCT) images for dose recomputations. Phys Med Biol 2005; 50:4259-76. [PMID: 16148392 DOI: 10.1088/0031-9155/50/18/002] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Megavoltage CT (MVCT) images of patients are acquired daily on a helical tomotherapy unit (TomoTherapy, Inc., Madison, WI). While these images are used primarily for patient alignment, they can also be used to recalculate the treatment plan for the patient anatomy of the day. The use of MVCT images for dose computations requires a reliable CT number to electron density calibration curve. In this work, we tested the stability of the MVCT numbers by determining the variation of this calibration with spatial arrangement of the phantom, time and MVCT acquisition parameters. The two calibration curves that represent the largest variations were applied to six clinical MVCT images for recalculations to test for dosimetric uncertainties. Among the six cases tested, the largest difference in any of the dosimetric endpoints was 3.1% but more typically the dosimetric endpoints varied by less than 2%. Using an average CT to electron density calibration and a thorax phantom, a series of end-to-end tests were run. Using a rigid phantom, recalculated dose volume histograms (DVHs) were compared with plan DVHs. Using a deformed phantom, recalculated point dose variations were compared with measurements. The MVCT field of view is limited and the image space outside this field of view can be filled in with information from the planning kVCT. This merging technique was tested for a rigid phantom. Finally, the influence of the MVCT slice thickness on the dose recalculation was investigated. The dosimetric differences observed in all phantom tests were within the range of dosimetric uncertainties observed due to variations in the calibration curve. The use of MVCT images allows the assessment of daily dose distributions with an accuracy that is similar to that of the initial kVCT dose calculation.
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Affiliation(s)
- K M Langen
- Department of Radiation Oncology, M. D. Anderson Cancer Center Orlando, Orlando, FL 32806, USA.
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Abstract
A neonate receiving hyperalimentation through a peripherally inserted central catheter (PICC) had acute abdominal distension and respiratory distress. She was found to have extravasated a 9-cm x 9-cm pocket of hyperalimentation into the liver parenchyma, most likely caused by arterial placement of the PICC. She had severe anasarca and markedly decreased synthetic liver function. After 3 weeks of intensive care, she began to diurese. Her respiratory status subsequently improved, she started feeding, and her liver function test results returned to normal. This case shows the remarkable regenerative capacity of the neonatal liver and provides a rationale for conservative management of this rare but morbid PICC complication.
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Affiliation(s)
- Shannon L Meeks
- Division of Pediatric Surgery, Department of Surgery, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908-0386, USA
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Lester NV, Hopkins AL, Bova FJ, Friedman WA, Buatti JM, Meeks SL, Chrisman CL. Radiosurgery using a stereotactic headframe system for irradiation of brain tumors in dogs. J Am Vet Med Assoc 2001; 219:1562-7, 1550. [PMID: 11759994 DOI: 10.2460/javma.2001.219.1562] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Radiation therapy of brain tumors in dogs typically involves administration of multiple fractions over several weeks. Fractionation is used to minimize damage to normal tissue. Radiosurgery uses multiple non-coplanar stereotactically focused beams of radiation in a series of arcs to deliver a single dose to the target with extreme accuracy. The large number of beams facilitates a high degree of conformation between the treatment area and the target tumor and allows for a steep dose gradient; the use of nonintersecting arcs minimizes exposure of normal tissue. Computed tomography with a stereotactic localizer secured to the skull allows generation of a 3-dimensional image of the target and provides accurate spatial coordinates for computerized treatment planning and delivery. Three dogs were treated with radiosurgery, using 1,000 to 1,500 cGy. A linear accelerator mounted on a rotating gantry was used to generate and deliver the radiation. Two dogs with meningiomas survived 227 and 56 weeks after radiosurgery. A dog with an oligodendroglioma survived 66 weeks. No complications were observed following the use of this technique.
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Affiliation(s)
- N V Lester
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA
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Ryken TC, Meeks SL, Traynelis V, Haller J, Bouchet LG, Bova FJ, Pennington EC, Buatti JM. Ultrasonographic guidance for spinal extracranial radiosurgery: technique and application for metastatic spinal lesions. Neurosurg Focus 2001; 11:e8. [PMID: 16464000 DOI: 10.3171/foc.2001.11.6.9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The relatively stationary anatomy of the intracranial compartment has allowed the development of stereotactic radiosurgery as an effective treatment option for many intracranial lesions. Difficulty in accurately tracking extracranial targets has limited its development in the treatment of these lesions. The ability to track extracranial structures in real time with ultrasound images allows a system to upgrade and interface pretreatment volumetric images for extracranial applications. In this report the authors describe this technique as applied to the treatment of localized metastatic spinal disease.
Methods
The extracranial stereotactic system consists of an optically tracked ultrasonography unit that can be registered to a linear accelerator coordinate system. Stereotactic ultrasound images are acquired following patient positioning, based on a pretreatment computerized tomography (CT) simulation. The soft-tissue shifts between the virtual CT-based treatment plan and the actual treatment are determined. The degree of patient offset is tracked and used to correct the treatment plan.
The ultrasonography-based stereotactic navigation system is accurate to within an approximate means of 1.5 mm based on testing with an absolute coordinate phantom. A radiosurgical treatment was delivered using the system for localization of a metastatic spinal lesion. Compared with the virtual CT simulation, the actual treatment plan isocenter was shifted 12.2 mm based on the stereotactic ultrasound image. The patient was treated using noncoplanar beams to a dose of 15.0 Gy to the 80% isodose shell in a single fraction.
Conclusions
A system for high-precision radiosurgical treatment of metastatic spinal tumors has been developed, tested, and applied clinically. Optical tracking of the ultrasonography probe provides real-time tracking of the patient anatomy and allows computation of the target displacement prior to treatment delivery. The results reported here suggest the feasibility and safety of the technique.
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Affiliation(s)
- T C Ryken
- Department of Neurosurgery, University of Iowa, Iowa City, Iowa 52242-1077, USA.
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Ryken TC, Meeks SL, Pennington EC, Hitchon P, Traynelis V, Mayr NA, Bova FJ, Friedman WA, Buatti JM. Initial clinical experience with frameless stereotactic radiosurgery: analysis of accuracy and feasibility. Int J Radiat Oncol Biol Phys 2001; 51:1152-8. [PMID: 11704340 DOI: 10.1016/s0360-3016(01)01756-4] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To report on preliminary clinical experience with a novel image-guided frameless stereotactic radiosurgery system. METHODS AND MATERIALS Fifteen patients ranging in age from 14 to 81 received radiosurgery using a commercially available frameless stereotactic radiosurgery system. Pathologic diagnoses included metastases (12), recurrent primary intracranial sarcoma (1), recurrent central nervous system (CNS) lymphoma (1), and medulloblastoma with supratentorial seeding (1). Treatment accuracy was assessed from image localization of the stereotactic reference array and reproducibility of biteplate reseating. We chose 0.3 mm vector translation error and 0.3 degree rotation about each axis as the maximum tolerated misalignment before treating each arc. RESULTS The biteplates were found on average to reseat with a reproducibility of 0.24 mm. The mean registration error from CT localization was found to be 0.5 mm, which predicts that the average error at isocenter was 0.82 mm. No patient treatment was delivered beyond the maximum tolerated misalignment. The radiosurgery treatment was delivered in approximately 25 min per patient. CONCLUSION Our initial clinical experience with stereotactic radiotherapy using the infrared camera guidance system was promising, demonstrating clinical feasibility and accuracy comparable to many frame-based systems.
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Affiliation(s)
- T C Ryken
- Department of Neurosurgery, University of Iowa College of Medicine, Iowa City, IA, USA
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Abstract
In stereotactic radiosurgery and radiotherapy treatment planning, the steepest dose gradient is obtained by using beam arrangements with maximal beam separation. We propose a treatment plan optimization method that optimizes beam directions from the starting point of a set of isotropically convergent beams, as suggested by Webb. The optimization process then individually steers each beam to the best position, based on beam's-eye-view (BEV) critical structure overlaps with the target projection and the target's projected cross sectional area at each beam position. This final optimized beam arrangement maintains a large angular separation between adjacent beams while conformally avoiding critical structures. As shown by a radiosurgery plan, this optimization method improves the critical structure sparing properties of an unoptimized isotropic beam bouquet, while maintaining the same degree of dose conformity and dose gradient. This method provides a simple means of designing static beam radiosurgery plans with conformality indices that are within established guidelines for radiosurgery planning, and with dose gradients that approach those achieved in conventional radiosurgery planning.
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Affiliation(s)
- T H Wagner
- Southside Cancer Center, Radiation Oncology Department, Jacksonville, FL 32207, USA
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Abstract
BACKGROUND AND PURPOSE Previously, we reported on development of an optically guided system for 3D conformal intracranial radiotherapy using multiple noncoplanar fixed fields. In this paper we report on the extension of our system for stereotactic fractionated radiotherapy to include intensity modulated static ports. METHODS AND MATERIALS A 3D treatment plan with maximum beam separation is developed in the stereotactic space established by an optically guided system. Gantry angles are chosen such that each beam has a unique entrance and exit pathway, avoids the critical structures, and has a minimal beam's eye view projection. Once, a satisfactory treatment plan is found using this geometric approach an inverse treatment plan is developed using the beam portals established previously. The purpose of adding inverse planing is two fold, on the one hand it allows further reduction of margins around the PTV, while on the other hand it affords the possibility of conformal avoidance of critical structures that are close to or abut the PTV. RESULTS The use of the optically guided system in conjunction with intensity modulated noncoplanar radiotherapy treatment planning using fixed fields allows the generation of highly conformal treatment plans that exhibit smaller 90, 70, and 50% of prescription dose isodose volumes, improved PITV ratios, comparable or improved EUD, smaller NTD(mean) for the critical structures, and an inhomogeneity index that is within generally accepted limits. CONCLUSION Because optically guided technology improves the accuracy of patient localization relative to the linac isocenter and allows real-time monitoring of patient position, the planning target volume needs to be corrected only for the limitations of image resolution. Intensity modulated static beam radiotherapy planning then provides the user the ability to further reduce margins on the PTV and to conform very closely to this smaller target volume, and enhances the normal tissue sparing, and high degree of conformality possible with 3D conformal radiotherapy. In addition, since optically guided technology affords improved patient localization and online monitoring of patient position during treatment delivery it allows for safe and efficient delivery of intensity modulated radiotherapy.
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Affiliation(s)
- W A Tomé
- Department of Human Oncology, University of Wisconsin, K4/B100 Clinical Science Center, 600 Highland Avenue, Madison, WI 53792, USA
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Abstract
OBJECT The aim of this study was to identify factors associated with delayed cranial neuropathy following radiosurgery for vestibular schwannoma (VS or acoustic neuroma) and to determine how such factors may be manipulated to minimize the incidence of radiosurgical complications while maintaining high rates of tumor control. METHODS From July 1988 to June 1998, 149 cases of VS were treated using linear accelerator radiosurgery at the University of Florida. In each of these cases, the patient's tumor and brainstem were contoured in 1-mm slices on the original radiosurgical targeting images. Resulting tumor and brainstem volumes were coupled with the original radiosurgery plans to generate dose-volume histograms. Various tumor dimensions were also measured to estimate the length of cranial nerve that would be irradiated. Patient follow-up data, including evidence of cranial neuropathy and radiographic tumor control, were obtained from a prospectively maintained, computerized database. The authors performed statistical analyses to compare the incidence of posttreatment cranial neuropathies or tumor growth between patient strata defined by risk factors of interest. One hundred thirty-nine of the 149 patients were included in the analysis of complications. The median duration of clinical follow up for this group was 36 months (range 18-94 months). The tumor control analysis included 133 patients. The median duration of radiological follow up in this group was 34 months (range 6-94 months). The overall 2-year actuarial incidences of facial and trigeminal neuropathies were 11.8% and 9.5%, respectively. In 41 patients treated before 1994, the incidences of facial and trigeminal neuropathies were both 29%, but in the 108 patients treated since January 1994, these rates declined to 5% and 2%, respectively. An evaluation of multiple risk factor models showed that maximum radiation dose to the brainstem, treatment era (pre-1994 compared with 1994 or later), and prior surgical resection were all simultaneously informative predictors of cranial neuropathy risk. The radiation dose prescribed to the tumor margin could be substituted for the maximum dose to the brainstem with a small loss in predictive strength. The pons-petrous tumor diameter was an additional statistically significant simultaneous predictor of trigeminal neuropathy risk, whereas the distance from the brainstem to the end of the tumor in the petrous bone was an additional marginally significant simultaneous predictor of facial neuropathy risk. The overall radiological tumor control rate was 93% (59% tumors regressed, 34% remained stable, and 7.5% enlarged), and the 5-year actuarial tumor control rate was 87% (95% confidence interval [CI] 76-98%). Analysis revealed that a radiation dose cutpoint of 10 Gy compared with more than 10 Gy prescribed to the tumor margin yielded the greatest relative difference in tumor growth risk (relative risk 2.4, 95% CI 0.6-9.3), although this difference was not statistically significant (p = 0.207). CONCLUSIONS Five points must be noted. 1) Radiosurgery is a safe, effective treatment for small VSs. 2) Reduction in the radiation dose has played the most important role in reducing the complications associated with VS radiosurgery. 3) The dose to the brainstem is a more informative predictor of postradiosurgical cranial neuropathy than the length of the nerve that is irradiated. 4) Prior resection increases the risk of late cranial neuropathies after radiosurgery. 5) A prescription dose of 12.5 Gy to the tumor margin resulted in the best combination of maximum tumor control and minimum complications in this series.
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Affiliation(s)
- K D Foote
- Department of Neurosurgery, University of Florida, Gainesville, USA
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Bouchet LG, Meeks SL, Goodchild G, Bova FJ, Buatti JM, Friedman WA. Calibration of three-dimensional ultrasound images for image-guided radiation therapy. Phys Med Biol 2001; 46:559-77. [PMID: 11229734 DOI: 10.1088/0031-9155/46/2/321] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new technique of patient positioning for radiotherapy/radiosurgery of extracranial tumours using three-dimensional (3D) ultrasound images has been developed. The ultrasound probe position is tracked within the treatment room via infrared light emitting diodes (IRLEDs) attached to the probe. In order to retrieve the corresponding room position of the ultrasound image, we developed an initial ultrasound probe calibration technique for both 2D and 3D ultrasound systems. This technique is based on knowledge of points in both room and image coordinates. We first tested the performance of three algorithms in retrieving geometrical transformations using synthetic data with different noise levels. Closed form solution algorithms (singular value decomposition and Horn's quaternion algorithms) were shown to outperform the Hooke and Jeeves iterative algorithm in both speed and accuracy. Furthermore, these simulations show that for a random noise level of 2.5, 5, 7.5 and 10 mm, the number of points required for a transformation accuracy better than 1 mm is 25, 100, 200 and 500 points respectively. Finally, we verified the tracking accuracy of this system using a specially designed ultrasound phantom. Since ultrasound images have a high noise level, we designed an ultrasound phantom that provides a large number of points for the calibration. This tissue equivalent phantom is made of nylon wires, and its room position is optically tracked using IRLEDs. By obtaining multiple images through the nylon wires, the calibration technique uses an average of 300 points for 3D ultrasound volumes and 200 for 2D ultrasound images, and its stability is very good for both rotation (standard deviation: 0.4 degrees) and translation (standard deviation: 0.3 mm) transformations. After this initial calibration procedure, the position of any voxel in the ultrasound image volume can be determined in world space, thereby allowing real-time image guidance of therapeutic procedures. Finally, the overall tracking accuracy of our 3D ultrasound image-guided positioning system was measured to be on average 0.2 mm, 0.9 mm and 0.6 mm for the AP, lateral and axial directions respectively.
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Affiliation(s)
- L G Bouchet
- Department of Neurological Surgery, University of Florida, Gainesville, USA.
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Wagner TH, Yi T, Meeks SL, Bova FJ, Brechner BL, Chen Y, Buatti JM, Friedman WA, Foote KD, Bouchet LG. A geometrically based method for automated radiosurgery planning. Int J Radiat Oncol Biol Phys 2000; 48:1599-611. [PMID: 11121667 DOI: 10.1016/s0360-3016(00)00790-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE A geometrically based method of multiple isocenter linear accelerator radiosurgery treatment planning optimization was developed, based on a target's solid shape. METHODS AND MATERIALS Our method uses an edge detection process to determine the optimal sphere packing arrangement with which to cover the planning target. The sphere packing arrangement is converted into a radiosurgery treatment plan by substituting the isocenter locations and collimator sizes for the spheres. RESULTS This method is demonstrated on a set of 5 irregularly shaped phantom targets, as well as a set of 10 clinical example cases ranging from simple to very complex in planning difficulty. Using a prototype implementation of the method and standard dosimetric radiosurgery treatment planning tools, feasible treatment plans were developed for each target. The treatment plans generated for the phantom targets showed excellent dose conformity and acceptable dose homogeneity within the target volume. The algorithm was able to generate a radiosurgery plan conforming to the Radiation Therapy Oncology Group (RTOG) guidelines on radiosurgery for every clinical and phantom target examined. CONCLUSIONS This automated planning method can serve as a valuable tool to assist treatment planners in rapidly and consistently designing conformal multiple isocenter radiosurgery treatment plans.
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Affiliation(s)
- T H Wagner
- Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL, USA
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46
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Buatti JM, Meeks SL, Friedman WA, Bova FJ. Stereotactic radiosurgery: techniques and clinical applications. Surg Oncol Clin N Am 2000; 9:469-87, viii. [PMID: 10853137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Radiation is a common treatment modality for cancer. Although commonly used, the treatment techniques of radiation delivery have changed substantially. One of the most important changes in implementation is the widespread application of stereotactic techniques and their acceptance into the mainstream of radiotherapeutic delivery. The distinguishing characteristics of stereotactic radiosurgery and its current and future application are important for all physicians to understand. This article discusses these treatment techniques and applications from the perspective of a surgical oncologist.
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Affiliation(s)
- J M Buatti
- Division of Radiation Oncology, University of Iowa College of Medicine, Iowa City 52242, USA.
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Abstract
PURPOSE Currently, optimally precise delivery of intracranial radiotherapy is possible with stereotactic radiosurgery and fractionated stereotactic radiotherapy. We report on an optimally precise optically guided system for three-dimensional (3D) conformal radiotherapy using multiple noncoplanar fixed fields. METHODS AND MATERIALS The optically guided system detects infrared light emitting diodes (IRLEDs) attached to a custom bite plate linked to the patient's maxillary dentition. The IRLEDs are monitored by a commercially available stereo camera system, which is interfaced to a personal computer. An IRLED reference is established with the patient at the selected stereotactic isocenter, and the computer reports the patient's current position based on the location of the IRLEDs relative to this reference position. Using this readout from the computer, the patient may be dialed directly to the desired position in stereotactic space. The patient is localized on the first day and a reference file is established for 5 different couch positions. The patient's image data are then imported into a commercial convolution-based 3D radiotherapy planning system. The previously established isocenter and couch positions are then used as a template upon which to design a conformal 3D plan with maximum beam separation. RESULTS The use of the optically guided system in conjunction with noncoplanar radiotherapy treatment planning using fixed fields allows the generation of highly conformal treatment plans that exhibit a high degree of dose homogeneity and a steep dose gradient. To date, this approach has been used to treat 28 patients. CONCLUSION Because IRLED technology improves the accuracy of patient localization relative to the linac isocenter and allows real-time monitoring of patient position, one can choose treatment-field margins that only account for beam penumbra and image resolution without adding margin to account for larger and poorly defined setup uncertainty. This approach enhances the normal tissue sparing, high degree of conformality, and homogeneity characteristics possible with 3D conformal radiotherapy.
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Affiliation(s)
- W A Tome
- Department of Human Oncology, University of Wisconsin Medical School, Madison, WI, USA
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Meeks SL, Buatti JM, Foote KD, Friedman WA, Bova FJ. Calculation of cranial nerve complication probability for acoustic neuroma radiosurgery. Int J Radiat Oncol Biol Phys 2000; 47:597-602. [PMID: 10837941 DOI: 10.1016/s0360-3016(00)00493-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Estimations of complications from stereotactic radiosurgery usually rely simply on dose-volume or dose-diameter isoeffect curves. Due to the sparse clinical data available, these curves have typically not considered the target location in the brain, target histology, or treatment plan conformality as parameters in the calculation. In this study, a predictive model was generated to estimate the probability of cranial neuropathies as a result of acoustic schwannoma radiosurgery. METHODS AND MATERIALS The dose-volume histogram reduction scheme was used to calculate the normal tissue complication probability (NTCP) from brainstem dose-volume histograms. The model's fitting parameters were optimized to provide the best fit to the observed complication data for acoustic neuroma patients treated with stereotactic radiosurgery at the University of Florida. The calculation was then applied to the remainder of the patients in the database. RESULTS The best fit to our clinical data was obtained using n = 0.04, m = 0.15, and alpha/beta = 2.1 Gy(-1). Although the fitting parameter m is relatively consistent with ranges found in the literature, both the volume parameter, n, and alpha/beta are much smaller than the values quoted in the literature. The fit to our clinical data indicates that brainstem, or possibly a specific portion of the brainstem, is more radiosensitive than the parameters in the literature indicate, and that there is very little volume effect; in other words, irradiation of a small fraction of the brainstem yields NTCPs that are nearly as high as those calculated for entire volume irradiation. These new fitting parameters are specific to acoustic neuroma radiosurgery, and the small volume effect that we observe may be an artifact of the fixed relationship of acoustic tumors to specific regions of the brainstem. Applying the model to our patient database, we calculate an average NTCP of 7.2% for patients who had no cranial nerve complications, and the average NTCP for was 66% for patients who sustained a cranial neuropathy. For the entire patient population, the actual percentage of patients suffering either facial or trigeminal neuropathy was 14.7%, whereas the calculated average NTCP was 14.8%. DISCUSSION NTCP calculations using brainstem dose-volume histograms can be used to estimate the rate of cranial neuropathies from acoustic neuroma radiosurgery. More clinical data and further study will lead to refinement of the model with time.
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Affiliation(s)
- S L Meeks
- Division of Radiation Oncology, University of Iowa, Iowa City 52242. USA.
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Abstract
PURPOSE Infrared light-emitting diodes (IRLEDs) have been used for optic-guided stereotactic radiotherapy localization at the University of Florida since 1995. The current paradigm requires stereotactic head ring placement for the patient's first fraction. The stereotactic coordinates and treatment plan are determined relative to this head ring. The IRLEDs are attached to the patient via a maxillary bite plate, and the position of the IRLEDs relative to linac isocenter is saved to file. These positions are then recalled for each subsequent treatment to position the patient for fractionated therapy. The purpose of this article was to report a method of predicting the desired IRLED locations without need for the invasive head ring. METHODS AND MATERIALS To achieve the goal of frameless optic-guided radiotherapy, a method is required for direct localization of the IRLED positions from a CT scan. Because it is difficult to localize the exact point of light emission from a CT scan of an IRLED, a new bite plate was designed that contains eight aluminum fiducial markers along with the six IRLEDs. After a calibration procedure to establish the spatial relationship of the IRLEDs to the aluminum fiducial markers, the stereotactic coordinates of the IRLED light emission points are determined by localizing the aluminum fiducial markers in a stereotactic CT scan. RESULTS To test the accuracy of direct CT determination of the IRLED positions, phantom tests were performed. The average accuracy of isocenter localization using the IRLED bite plate was 0.65 +/- 0. 17 mm for these phantom tests. In addition, the optic-guided system has a unique compatibility with the stereotactic head ring. Therefore, the isocentric localization capability was clinically tested using the stereotactic head ring as the absolute standard. The ongoing clinical trial has shown the frameless system to provide a patient localization accuracy of 1.11 +/- 0.3 mm compared with the head ring. CONCLUSION Optic-guided radiotherapy using IRLEDs provides a mechanism through which setup accuracy may be improved over conventional techniques. To date, this optic-guided therapy has been used only as a hybrid system that requires use of the stereotactic head ring for the first fraction. This has limited its use in the routine clinical setting. Computation of the desired IRLED positions eliminates the need for the invasive head ring for the first fraction. This allows application of optic-guided therapy to a larger cohort of patients, and also facilitates the initiation of extracranial optic-guided radiotherapy.
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Affiliation(s)
- S L Meeks
- Division of Radiation Oncology, University of Iowa College of Medicine, Iowa City, IA 52242, USA.
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