201
|
Moskowitz CH, Hamlin PA, Gabrilove J, Bertino JR, Portlock CS, Straus DJ, Gencarelli AN, Nimer SD, Zelenetz AD. Maintaining the dose intensity of ICE chemotherapy with a thrombopoietic agent, PEG-rHuMGDF, may confer a survival advantage in relapsed and refractory aggressive non-Hodgkin lymphoma. Ann Oncol 2007; 18:1842-50. [PMID: 17872903 DOI: 10.1093/annonc/mdm341] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION HDT/ASCT is standard for relapsed and refractory DLCL patients responding to second-line chemotherapy. We incorporated a thrombopoietic agent into the ICE chemotherapy program to potentially: decrease platelet associated toxicities, augment stem cell collection and maintain dose intensity. METHODS This randomized, double-blind, placebo-controlled phase I/II trial examines PEG-rHuMGDF versus placebo with ICE chemotherapy. Phase I compared three cohorts and defined a clinically effective dose (CED). Phase II evaluated the CED versus placebo. Outcome measures included safety, hematological end-points, stem cell collection and the impact of dose-intensity on outcome. RESULTS Forty-one patients with primary refractory (16) or relapsed DLCL (25) were treated; Response rates for evaluable patients are: 75% (12/16) for placebo and 82% (18/22) for PEG-rHuMGDF. PEG-rHuMGDF treated patients had significantly less grade IV thrombocytopenia, higher median platelet nadirs, and less platelet transfusion per cycle. ICE dose intensity was improved with PEG-rHuMGDF versus placebo: 75 versus 42% (P = 0.008). At 8.5 years median follow-up, overall and event-free survival are 47 and 31%, respectively. Patients treated on PEG-rHuMGDF versus placebo had improved survival (59 versus 31%, P = 0.06). CONCLUSION PEG-rHuMGDF ameliorated thrombocytopenia, improved platelet recovery, and maintained ICE dose intensity. Potential survival advantages conferred by maintaining dose intensity require validation with newer thrombopoietic agents.
Collapse
|
202
|
Afdhal NH, McHutchison JG. Review article: pharmacological approaches for the treatment of thrombocytopenia in patients with chronic liver disease and hepatitis C infection. Aliment Pharmacol Ther 2007; 26 Suppl 1:29-39. [PMID: 17958517 DOI: 10.1111/j.1365-2036.2007.03511.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Patients with chronic liver disease and hepatitis C virus (HCV) frequently experience thrombocytopenia that complicates the management of their disease. Traditional therapy for thrombocytopenia consists of platelet transfusion, which can be associated with significant safety and economic issues. Consequently, efforts have been directed toward developing novel approaches for the treatment of thrombocytopenia. AIM To summarize the available data on the limitations of traditional therapies and the effects of novel therapies currently in clinical development for the treatment of thrombocytopenia. RESULTS Recent research has begun to reveal the complex mechanisms that regulate thrombopoiesis. Cytokines and growth factors, such as interleukin-11 and thrombopoietin (TPO), play a key role in the production of platelets. A number of recent clinical studies have provided evidence that pharmacologic agents that target megakaryocyte precursors and stimulate thrombopoiesis can effectively reverse thrombocytopenia. Here, we review the regulation of thrombopoiesis, the role of TPO, and a number of novel compounds that stimulate platelet production by acting through the TPO receptor. Agents that stimulate TPO include the orally available nonpeptidic agonists eltrombopag and AKR-501, peptidic agonists AMG-531 and Peg-TPOmp, and small engineered antibodies. CONCLUSION Results from clinical trials with these agents in healthy subjects confirm that activation of thrombopoiesis via the TPO pathway is an effective method of stimulating platelet production. This approach may provide safer, more effective treatment for thrombocytopenia in patients with chronic liver disease. Several of these agents are currently being tested in large scale trials.
Collapse
Affiliation(s)
- N H Afdhal
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
| | | |
Collapse
|
203
|
Abstract
BACKGROUND Patients with chronic immune thrombocytopenic purpura (ITP) only require treatment if they are bleeding, or prior to scheduled operations. Patients are also treated if platelet counts are very low. Some patients become refractory, relapse or do not respond to treatment with steroids. Splenectomy is effective in raising the platelet count in most patients, but as spontaneous remission may occur even after 1 year or more, it is justified to defer splenectomy. Furthermore, splenectomy and/or first-line treatment modalities may not suit all patients. Therefore, alternatives are desirable. MATERIALS This review will focus on anti-B cell therapy with rituximab, and two thrombopoietin mimetic agents that have entered clinical trials, AMG 531 and eltrombopag. These therapeutics have been studied in patients who were refractory to first-line treatment and/or splenectomy, and to defer splenectomy. RESULTS There are no controlled trials with rituximab, but clinical experience has shown a success rate of 40% to 60%. Encouraging phase 1 and 2 data have been published for both thrombopoietin mimetics; preliminary data from an open-label extension trial with AMG 531 and from phase 3 studies with eltrombopag further confirm their efficacy. CONCLUSION Clinical experience will ultimately determine the appropriate indications of these new treatments for ITP.
Collapse
Affiliation(s)
- S Panzer
- Clinic for Blood Group Serology, Medical University Vienna, Vienna, Austria.
| |
Collapse
|
204
|
Kuter DJ, Bain B, Mufti G, Bagg A, Hasserjian RP. Bone marrow fibrosis: pathophysiology and clinical significance of increased bone marrow stromal fibres. Br J Haematol 2007; 139:351-62. [PMID: 17910625 DOI: 10.1111/j.1365-2141.2007.06807.x] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In bone marrow biopsies, stromal structural fibres are detected by reticulin and trichrome stains, routine stains performed on bone marrow biopsy specimens in diagnostic laboratories. Increased reticulin staining (reticulin fibrosis) is associated with many benign and malignant conditions while increased trichrome staining (collagen fibrosis) is particularly prominent in late stages of severe myeloproliferative diseases or following tumour metastasis to the bone marrow. Recent evidence has shown that the amount of bone marrow reticulin staining often exhibits no correlation to disease severity, while the presence of type 1 collagen, as detected by trichrome staining, is often associated with more severe disease and a poorer prognosis. It was originally thought that increases in bone marrow stromal fibres themselves contributed to the haematopoietic abnormalities seen in certain diseases, but recent studies suggest that these increases are a result of underlying cellular abnormalities rather than a cause. A growing body of evidence suggests that increased deposition of bone marrow stromal fibres is mediated by transforming growth factor-beta and other factors elaborated by megakaryocytes, but it is likely that other cells, cytokines and growth factors are also involved. This suggests new avenues for investigation into the pathogenesis of various disorders associated with increased bone marrow stromal fibres.
Collapse
Affiliation(s)
- David J Kuter
- Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
| | | | | | | | | |
Collapse
|
205
|
|
206
|
Abstract
Multiple cytokines affect the cellular processes that occur during the transition of a hematopoietic stem cell (HSC) to a platelet. Thrombopoietin (TPO) is the physiological regulator of thrombopoiesis. Although a number of cytokines (interleukin [IL]-1, IL-3, and IL-6) were first evaluated for their ability to lessen the degree of thrombocytopenia occurring during a variety of clinical scenarios, their clinical development was abandoned due to their limited effectiveness or excessive toxicity. Clinical results with TPO and a truncated pegylated form of TPO, megakaryocyte growth and development factor (MGDF), were more promising, but the repeated use of MGDF resulted in the development of neutralizing antibodies. This adverse event halted the further clinical development of not only MGDF but also TPO. IL-11 also affects various stages of megakaryocytopoiesis and thrombopoiesis and its use has been shown to shorten the duration of chemotherapy-induced thrombocytopenia, which led to its approval by the US Food and Drug Administration (FDA). A growing number of new non-immunogenic peptides and non-peptide TPO agonists recently have entered clinical trials. These small molecules appear to be effective therapies and have acceptable toxicity, but additional clinical evaluation will be required prior to their approval for clinical use.
Collapse
Affiliation(s)
- Stefan O Ciurea
- University of Illinois at Chicago College of Medicine, Chicago, IL, USA
| | | |
Collapse
|
207
|
Abstract
Although development of first-generation thrombopoietic growth factors (recombinant human thrombopoietin [TPO] and pegylated recombinant human megakaryocyte growth and development factor [PEG-rHuMGDF]) was stopped due to development of antibodies to PEG-rHuMGDF, nonimmunogenic second-generation thrombopoietic growth factors with unique pharmacologic properties have been developed. TPO peptide mimetics contain TPO receptor-activating peptides inserted into complementarity-determining regions of Fab (Fab 59), attached to the IgG Fc region (AMG 531), or pegylated (Peg-TPOmp). Orally available, TPO nonpeptide mimetics (eltrombopag, AKR-501) bind and activate the TPO receptor by a mechanism different from TPO and may have an additive effect to TPO. TPO agonist antibodies are monoclonal antibodies activating the TPO receptor but modified in size [TPO minibodies; ie, VB22B sc(Fv)(2)] or immunoglobuln type (domain subclass-converted TPO agonist antibodies; ie, MA01G4G344). All second-generation thrombopoietic growth factors stimulate growth of TPO-dependent cell lines via JAK2/STAT signaling pathways and increase platelet counts in animals. When tested in healthy humans, TPO peptide and nonpeptide mimetics produced a dose-dependent rise in platelet count. AMG 531 and eltrombopag markedly increase platelet counts in patients with immune thrombocytopenic purpura, without significant adverse effects. One or more second-generation thrombopoietic growth factors should soon be clinically available for treating thrombocytopenic disorders.
Collapse
Affiliation(s)
- David J Kuter
- Hematology Division, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.
| |
Collapse
|
208
|
Jenkins JM, Williams D, Deng Y, Uhl J, Kitchen V, Collins D, Erickson-Miller CL. Phase 1 clinical study of eltrombopag, an oral, nonpeptide thrombopoietin receptor agonist. Blood 2007; 109:4739-41. [PMID: 17327409 DOI: 10.1182/blood-2006-11-057968] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Eltrombopag (SB-497 115) is a first-in-class, oral, small-molecule, nonpeptide agonist of the thrombopoietin receptor (TpoR), being developed as a treatment for thrombocytopenia of various etiologies. In this phase 1 placebo-controlled clinical trial in 73 healthy male subjects, eltrombopag was administered as once-daily oral capsules for 10 days at doses of 5, 10, 25, 30, 50, and 75 mg. The pharmacokinetics of eltrombopag were dose dependent and linear, and eltrombopag increased platelet counts in a dose-dependent manner. There were no apparent differences in the incidence or severity of adverse events in subjects receiving active or placebo study medication. These observations indicate that eltrombopag is a once-daily, oral TpoR agonist with demonstrated thrombopoietic activity in human subjects, encouraging further studies in patients with thrombocytopenia.
Collapse
Affiliation(s)
- Julian M Jenkins
- GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA.
| | | | | | | | | | | | | |
Collapse
|
209
|
Abstract
The myelodysplastic syndrome(s) (MDS), bone marrow stem cell malignancies that share pathogenetic overlap with acute myeloid leukemia, are characterized by peripheral blood cytopenias and, in more advanced subtypes, varied degrees of maturation arrest. Premature apoptosis of bone marrow cellular elements contributes to ineffective hematopoiesis, which is exacerbated by stromal production of inflammatory cytokines. Abrogation of the effects of these cytokines represents an area of active clinical research, particularly in the treatment of low-risk MDS. In high-risk MDS, the activation of oncogenes and the inactivation of tumor suppressor genes predominate over inhibitory cytokines as proliferation predominates over apoptosis. Agents such as thalidomide, lenalidomide and the hypomethylating drugs 5-azacytidine and decitabine have shown promising efficacy and tolerability in clinical trials, and may represent a springboard for future treatment combinations.
Collapse
Affiliation(s)
- Mikkael A Sekeres
- Cleveland Clinic Lerner College of Medicine, Department of Hematologic Oncology and Blood Disorders, Taussig Cancer Center, Cleveland Clinic, Cleveland, Ohio 44195, USA.
| |
Collapse
|
210
|
Platelet Growth Factors. Platelets 2007. [DOI: 10.1016/b978-012369367-9/50828-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
211
|
Abstract
AbstractThrombocytopenia is a primary manifestation of immune thrombocytopenic purpura (ITP) and may occur as a result of hepatitis C, malignancy, and treatment with chemotherapy. There is a need for additional means to treat thrombocytopenia in these settings. Recombinant thrombopoietin-like agents became available after the cloning of thrombopoietin in 1994. In clinical trials, these agents showed some efficacy in chemotherapy-induced thrombocytopenia, but their use was ultimately discontinued due to the development of neutralizing antibodies that cross-reacted with endogenous thrombopoietin and caused thrombocytopenia in healthy blood donors and other recipients. Subsequently, “second-generation” thrombopoietic agents without homology to thrombopoietin were developed. In the past 5 years, these second-generation thrombopoeitic growth factors have undergone substantial clinical development and have demonstrated safety, tolerability and efficacy in subjects with ITP and hepatitis C–related thrombocytopenia. These completed studies, many of which are available only in abstract form, and other ongoing studies suggest that thrombopoietic agents will enhance the hematologist’s ability to manage these and other causes of thrombocytopenia.
Collapse
|
212
|
Nam KL, Cho SH, Yang SW, Son DW, Jeon IS. Therapeutic Efficacy of a Single Dose of Anti-D Immunoglobulin 50µg/kg in Childhood Acute Immune Thrombocytopenic Purpura. THE KOREAN JOURNAL OF HEMATOLOGY 2007. [DOI: 10.5045/kjh.2007.42.3.258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Ki Lyong Nam
- Department of Pediatrics, Gil Medical Center, School of Medicine, Gachon University of Medicine and Science, Incheon, Korea
| | - Sang Hee Cho
- Department of Pediatrics, Gil Medical Center, School of Medicine, Gachon University of Medicine and Science, Incheon, Korea
| | - Sung Wan Yang
- Department of Pediatrics, Gil Medical Center, School of Medicine, Gachon University of Medicine and Science, Incheon, Korea
| | - Dong Woo Son
- Department of Pediatrics, Gil Medical Center, School of Medicine, Gachon University of Medicine and Science, Incheon, Korea
| | - In-sang Jeon
- Department of Pediatrics, Gil Medical Center, School of Medicine, Gachon University of Medicine and Science, Incheon, Korea
| |
Collapse
|
213
|
Szilvassy SJ. Haematopoietic stem and progenitor cell-targeted therapies for thrombocytopenia. Expert Opin Biol Ther 2006; 6:983-92. [PMID: 16989580 DOI: 10.1517/14712598.6.10.983] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This review discusses the present outlook for new thrombocytopenia therapies that induce haematopoietic stem and progenitor cells to proliferate, differentiate and produce functional platelets. A brief overview of megakaryopoiesis and its regulation by thrombopoietin (TPO) is followed by a discussion of how early experience with recombinant TPO therapies stimulated the search for novel TPO receptor ligands. A summary is then provided of the results of Phase I clinical trials with the new small molecule and peptide TPO mimetics that are in development at present. Finally, recent developments in the ex vivo expansion of primitive haematopoietic cells and the potential enhancement of cell-based therapies by haematopoietic growth factors in vivo are briefly summarised as part of a look towards the future.
Collapse
Affiliation(s)
- Stephen J Szilvassy
- Amgen, Inc., One Amgen Center Drive, MS 15-2-A, Thousand Oaks, CA 91320, USA.
| |
Collapse
|
214
|
Newland A, Caulier MT, Kappers-Klunne M, Schipperus MR, Lefrere F, Zwaginga JJ, Christal J, Chen CF, Nichol JL. An open-label, unit dose-finding study of AMG 531, a novel thrombopoiesis-stimulating peptibody, in patients with immune thrombocytopenic purpura. Br J Haematol 2006; 135:547-53. [PMID: 17061981 DOI: 10.1111/j.1365-2141.2006.06339.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract The objective of this open label, phase 1-2, multicentre trial was to evaluate the safety of AMG 531, a novel thrombopoiesis-stimulating peptibody, and its effect on platelet counts in adults with immune thrombocytopenic purpura. Four patients were assigned to each of four unit-dose cohorts: 30, 100, 300 or 500 microg, administered subcutaneously on days 1 and 15 (or day 22 if the day 15 platelet count was >50 x 10(9)/l). Safety was assessed by adverse event (AE) monitoring, clinical laboratory studies and antibody assays. Platelet response was defined as a platelet count double the baseline value and between 50 and 450 x 10(9)/l. Sixteen patients (10 women) were enrolled. The 500-microg cohort was discontinued because the first patient's platelet count became unacceptably high. AEs were generally expected and mild or moderate; the most frequent was headache (eight of 16 patients). Two patients experienced serious AEs related to AMG 531 (severe headache and elevated serum lactic dehydrogenase; thrombocytopenia). Platelet responses occurred with all doses and with a dose equivalent to >/=1 microg/kg in eight of 11 patients. In summary, patients tolerated AMG 531 well at the doses tested. No anti-AMG or antithrombopoietin antibodies were detected. Doses equivalent to >/=1 microg/kg increased platelet counts.
Collapse
Affiliation(s)
- Adrian Newland
- Barts and the London School of Medicine and Dentistry, Queen Mary, London, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
215
|
Bussel JB, Kuter DJ, George JN, McMillan R, Aledort LM, Conklin GT, Lichtin AE, Lyons RM, Nieva J, Wasser JS, Wiznitzer I, Kelly R, Chen CF, Nichol JL. AMG 531, a thrombopoiesis-stimulating protein, for chronic ITP. N Engl J Med 2006; 355:1672-81. [PMID: 17050891 DOI: 10.1056/nejmoa054626] [Citation(s) in RCA: 375] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Most current treatments for chronic immune thrombocytopenic purpura (ITP) act by decreasing platelet destruction. In a phase 1-2 study, we administered a thrombopoiesis-stimulating protein, AMG 531, to patients with ITP. METHODS In phase 1, 24 patients who had received at least one treatment for ITP were assigned to escalating-dose cohorts of 4 patients each and given two identical doses of AMG 531 (0.2 to 10 microg per kilogram of body weight). In phase 2, 21 patients were randomly assigned to receive six weekly subcutaneous injections of AMG 531 (1, 3, or 6 microg per kilogram) or placebo. The primary objective was to assess the safety of AMG 531; the secondary objective was to evaluate platelet counts during and after treatment. RESULTS No major adverse events that could be attributed directly to AMG 531 occurred during the treatment period; 4 of 41 patients had transient post-treatment worsening of thrombocytopenia. In phase 1, a platelet count that was within the targeted range (50,000 to 450,000 per cubic millimeter) and at least twice the baseline count was achieved in 4 of 12 patients given 3, 6, or 10 mug of AMG 531 per kilogram. Overall, a platelet count of at least 50,000 per cubic millimeter was achieved in 7 of 12 patients, including 3 with counts exceeding 450,000 per cubic millimeter. Increases in the platelet count were dose-dependent; mean peak counts were 163,000, 309,000, and 746,000 per cubic millimeter with 3, 6, and 10 microg of AMG 531 per kilogram [corrected], respectively. In phase 2, the targeted platelet range was achieved in 10 of 16 patients treated with 1 or 3 mug of AMG 531 per kilogram per week for 6 weeks. Mean peak counts were 135,000, 241,000, and 81,000 per cubic millimeter in the groups that received the 1-mug dose, the 3-mug dose, and placebo, respectively. CONCLUSIONS AMG 531 caused no major adverse events and increased platelet counts in patients with ITP. (ClinicalTrials.gov number, NCT00111475 [ClinicalTrials.gov].).
Collapse
|
216
|
Miale TD, Wong JYC, Ahmed I, Wagman LD. Multimodal management, including precisely targeted irradiation, in a severe refractory case of Evans syndrome. Pediatr Blood Cancer 2006; 47:726-8. [PMID: 16933267 DOI: 10.1002/pbc.20976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A challenging case of acute autoimmune thrombocytopenia (ITP) which evolved into a chronic refractory case of Evans syndrome over a period of more than 23 years is presented and may illustrate current therapeutic dilemmas now perplexing patients and clinicians. Newer modalities are being developed and their eventual role in the scheme of clinical management remains to be established. While this development unfolds, highly targeted radiotherapy was applied in this case to reduce platelet uptake by a refractory recurrent splenule with the goal of stabilizing the platelet count until promising investigational thrombopoietic agents or other newer, less toxic therapies might become available for wider application.
Collapse
MESH Headings
- Adult
- Anemia, Hemolytic, Autoimmune/drug therapy
- Anemia, Hemolytic, Autoimmune/radiotherapy
- Anemia, Hemolytic, Autoimmune/surgery
- Disease Management
- Female
- Humans
- Platelet Count
- Purpura, Thrombocytopenic, Idiopathic/drug therapy
- Purpura, Thrombocytopenic, Idiopathic/radiotherapy
- Purpura, Thrombocytopenic, Idiopathic/surgery
- Radiotherapy/instrumentation
- Radiotherapy/methods
- Recurrence
- Severity of Illness Index
- Splenectomy
- Syndrome
- Thrombocytopenia/drug therapy
- Thrombocytopenia/surgery
- Treatment Outcome
Collapse
Affiliation(s)
- Thomas D Miale
- Pediatric Hematology-Oncology Section, Fort Sanders Regional Medical Center, Knoxville, Tennessee 37950-0642, USA.
| | | | | | | |
Collapse
|
217
|
Abstract
Thrombopoietin (TPO) regulates megakaryopoiesis and the generation of platelets. Recombinant TPO has been investigated in clinical studies for use in thrombocytopenia with limited success. A new peptibody, AMG 531, has been shown to increase platelet counts in preclinical and Phase 1 and Phase 2 studies and to be generally safe and tolerable in those studies.
Collapse
MESH Headings
- Animals
- Carrier Proteins/administration & dosage
- Carrier Proteins/immunology
- Carrier Proteins/therapeutic use
- Clinical Trials, Phase I as Topic
- Clinical Trials, Phase II as Topic
- Dose-Response Relationship, Drug
- Humans
- Placebos
- Platelet Count
- Purpura, Thrombocytopenic, Idiopathic/drug therapy
- Purpura, Thrombocytopenic, Idiopathic/immunology
- Randomized Controlled Trials as Topic
- Receptors, Fc/administration & dosage
- Receptors, Fc/immunology
- Receptors, Fc/therapeutic use
- Recombinant Fusion Proteins
- Thrombopoiesis/drug effects
- Thrombopoiesis/immunology
- Thrombopoietin
Collapse
|
218
|
Baron F, Vanstraelen G, Beguin Y. Transfusions after nonmyeloablative or reduced-intensity conditioning regimens. Leukemia 2006; 20:2081-6. [PMID: 17039229 DOI: 10.1038/sj.leu.2404431] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- F Baron
- Department of Medicine, Division of Hematology, University of Liège, Liège, Belgium
| | | | | |
Collapse
|
219
|
Frederickson S, Renshaw MW, Lin B, Smith LM, Calveley P, Springhorn JP, Johnson K, Wang Y, Su X, Shen Y, Bowdish KS. A rationally designed agonist antibody fragment that functionally mimics thrombopoietin. Proc Natl Acad Sci U S A 2006; 103:14307-12. [PMID: 16973749 PMCID: PMC1599960 DOI: 10.1073/pnas.0602658103] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Indexed: 11/18/2022] Open
Abstract
By using rational design, antibody fragments (Fabs) that mimic thrombopoietin (TPO) were created. A peptide with cMpl receptor-binding capability was grafted into different complementarity-determining regions of a fully human Fab scaffold. Functional presentation of the peptide was optimized by using phage display and cell-based panning. Select antibodies and fragments containing two grafted peptides were assayed for their ability to stimulate the cMpl receptor in vitro. Several candidates demonstrated agonist activity in an in vitro cMpl receptor signaling reporter assay, including Fab59, which was estimated to be equipotent to TPO. Fab59 additionally was able to effectively stimulate platelet production in normal mice. These rationally designed mimetic Fabs may provide a therapeutic intervention for thrombocytopenia while avoiding the potential generation of neutralizing antibodies to endogenous TPO. Furthermore, this study demonstrates a method by which short-lived linear peptides with binding activity may be converted to more stable and potent agonists capable of activating cell surface receptors.
Collapse
Affiliation(s)
- Shana Frederickson
- *Alexion Antibody Technologies, Inc., 3985-A Sorrento Valley Boulevard, San Diego, CA 92121; and
| | - Mark W. Renshaw
- *Alexion Antibody Technologies, Inc., 3985-A Sorrento Valley Boulevard, San Diego, CA 92121; and
| | - Bing Lin
- *Alexion Antibody Technologies, Inc., 3985-A Sorrento Valley Boulevard, San Diego, CA 92121; and
| | - Lynette M. Smith
- *Alexion Antibody Technologies, Inc., 3985-A Sorrento Valley Boulevard, San Diego, CA 92121; and
| | - Peter Calveley
- *Alexion Antibody Technologies, Inc., 3985-A Sorrento Valley Boulevard, San Diego, CA 92121; and
| | | | - Krista Johnson
- Alexion Pharmaceuticals, Inc., 352 Knotter Drive, Cheshire, CT 06410
| | - Yi Wang
- Alexion Pharmaceuticals, Inc., 352 Knotter Drive, Cheshire, CT 06410
| | - Xiao Su
- Alexion Pharmaceuticals, Inc., 352 Knotter Drive, Cheshire, CT 06410
| | - Yamin Shen
- Alexion Pharmaceuticals, Inc., 352 Knotter Drive, Cheshire, CT 06410
| | - Katherine S. Bowdish
- *Alexion Antibody Technologies, Inc., 3985-A Sorrento Valley Boulevard, San Diego, CA 92121; and
| |
Collapse
|
220
|
|
221
|
Geddis AE. Inherited Thrombocytopenia: Congenital Amegakaryocytic Thrombocytopenia and Thrombocytopenia With Absent Radii. Semin Hematol 2006; 43:196-203. [PMID: 16822462 DOI: 10.1053/j.seminhematol.2006.04.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Thrombocytopenia in the newborn period can signify an inherited platelet disorder. Congenital amegakaryocytic thrombocytopenia (CAMT) and thrombocytopenia with absent radii (TAR) share features of isolated thrombocytopenia, reduced or absent marrow megakaryocytes, impaired responsiveness to thrombopoietin (TPO), and high plasma TPO levels. These disorders are most readily distinguished from each other by the finding of radial aplasia in TAR and the presence of c-MPL mutations in CAMT. In addition, their long-term outcomes are strikingly different: the development of trilineage marrow failure in CAMT in contrast to the general improvement of thrombocytopenia in TAR. The differential diagnosis for CAMT and TAR also includes other congenital disorders in which thrombocytopenia and radial abnormalities can be seen. In this article we will review our molecular and clinical understanding of these two inherited disorders of amegakaryocytosis.
Collapse
Affiliation(s)
- Amy E Geddis
- Department of Pediatrics, Division of Pediatric Hematology-Oncology, University of California San Diego, La Jolla, CA, USA.
| |
Collapse
|
222
|
Kurtin SE. Advances in the management of low- to intermediate-risk myelodysplastic syndrome: Integrating the National Comprehensive Cancer Network guidelines. Clin J Oncol Nurs 2006; 10:197-208. [PMID: 16708703 DOI: 10.1188/06.cjon.197-208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Myelodysplastic syndromes (MDSs) are a group of hematologic diseases that present unique challenges for oncology nurses, especially because patients with the disorders are being seen more often in oncology practices. An increasing array of therapeutic options are available, and the National Comprehensive Cancer Network published its first clinical practice guidelines for MDSs in 2004. This article provides oncology nurses with the most recent data on supportive care as well as emerging therapies for patients with low- to intermediate-risk MDS.
Collapse
|
223
|
Abstract
Myeloid growth factors, such as granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, have been used to decrease the duration of chemotherapy-induced neutropenia and thereby reduce the incidence and severity of infections in various regimens used to treat acute myeloid leukemia and acute lymphoblastic leukemia. These growth factors have also been used to recruit dormant myeloid leukemia cells into the S phase of cell cycle in order to increase their susceptibility to the antileukemic effects of agents such as cytarabine. Multiple prospective randomized trials have examined the benefit and safety of the addition of growth factors before, during, and after chemotherapy. A reduction in the duration of neutropenia has been the most consistent finding; this has not been associated with stimulation of leukemia cells, the main concern of using this strategy. Unfortunately, few studies have reported a benefit in prolonging the duration of disease-free survival or overall survival. Other cytokines, including interleukins and thrombopoietin, have also been evaluated for their theoretical ability to recruit immune mechanisms to eradicate residual leukemia burden after chemotherapy, and to stimulate platelet production. In this review, we summarize the clinical experience with these growth factors in treating acute leukemias.
Collapse
Affiliation(s)
- F Ravandi
- Department of Leukemia, University of Texas - MD Anderson Cancer Center, Houston, TX 77030, USA.
| |
Collapse
|
224
|
|
225
|
Abstract
The year 2004 represents a milestone for the biosensor research community: in this year, over 1000 articles were published describing experiments performed using commercially available systems. The 1038 papers we found represent an approximately 10% increase over the past year and demonstrate that the implementation of biosensors continues to expand at a healthy pace. We evaluated the data presented in each paper and compiled a 'top 10' list. These 10 articles, which we recommend every biosensor user reads, describe well-performed kinetic, equilibrium and qualitative/screening studies, provide comparisons between binding parameters obtained from different biosensor users, as well as from biosensor- and solution-based interaction analyses, and summarize the cutting-edge applications of the technology. We also re-iterate some of the experimental pitfalls that lead to sub-optimal data and over-interpreted results. We are hopeful that the biosensor community, by applying the hints we outline, will obtain data on a par with that presented in the 10 spotlighted articles. This will ensure that the scientific community at large can be confident in the data we report from optical biosensors.
Collapse
Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
| | | |
Collapse
|