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Pravdic Z, Suvajdzic-Vukovic N, Djurdjevic P, Pantic N, Bukumiric Z, Virijevic M, Todorovic-Tirnanic M, Thachil J, Mitrovic M. Platelet kinetics in patients with chronic immune thrombocytopaenia treated with thrombopoietin receptor agonists. Eur J Haematol 2023; 110:548-553. [PMID: 36656555 DOI: 10.1111/ejh.13929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 12/30/2022] [Accepted: 01/13/2023] [Indexed: 01/20/2023]
Abstract
INTRODUCTION Thrombopoietin receptor agonists (TPO-RAs) increase platelet counts (PC) in the majority of patients with chronic immune thrombocytopaenia (ITP). Platelet kinetics study (PKS) might contribute to the understanding of mechanisms that lead to durable response. OBJECTIVES To evaluate the effects of TPO-RAs on PKS parameters in chronic ITP patients. METHODS Fifteen chronic ITP patients, aged 59 years [range: 22-84], female/male: 10/5, splenectomised 7/15, were treated with TPO-RAs (eltrombopag/romiplostim: 11/4). Durable response was defined as PC ≥30 × 109 /L at 6 months. Autologous 111 Indium-oxinate PKS was performed before and 5 months after TPO-RAs initiation. Accordingly, platelet survival (PS), platelet turnover, production ratio and sequestration site were assessed. RESULTS Durable response was achieved in 13/15 of patients (eltrombopag/romiplostim: 10/3). Pre-treatment parameters were: PC 10 × 109 /L [range: 1-110], PS 0.5 days [range: 0.1-1.7 (normal values: 7-10)], platelet turnover 30 857 Plt/μL/day [range: 944-103 500] and platelet production ratio 0.64 [range: 0.01-3.2 (normal values: 1 ± 0.2)]. Post-treatment assessment showed significantly higher: PC 92.5 × 109 /L [range: 28-260, p = .001], PS 2.2 days [range: 0.1-3.6, p = .008], platelet turnover 70 213 Plt/μL/day [range: 2800-462 236, p = .02] and platelet production ratio 1.8 [range: 0.5-37.9, p = .011] compared to the pre-treatment values. Platelet sequestration site altered in 3/15 treated with TPO-RAs. CONCLUSIONS TPO-RAs could increase PC by simultaneous increasing of platelet production and decreasing of platelet destruction.
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Affiliation(s)
- Zlatko Pravdic
- Clinic of Haematology, University Clinical Centre of Serbia, Belgrade, Serbia
| | - Nada Suvajdzic-Vukovic
- Clinic of Haematology, University Clinical Centre of Serbia, Belgrade, Serbia.,Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Predrag Djurdjevic
- Clinic of Haematology, Clinical Centre of Kragujevac, Kragujevac, Serbia.,Faculty of Medicine, University of Kragujevac, Kragujevac, Serbia
| | - Nikola Pantic
- Clinic of Haematology, University Clinical Centre of Serbia, Belgrade, Serbia
| | - Zoran Bukumiric
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia.,Institute of Medical Statistics and Informatics, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Marijana Virijevic
- Clinic of Haematology, University Clinical Centre of Serbia, Belgrade, Serbia.,Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Mila Todorovic-Tirnanic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia.,Centre of Nuclear Medicine, Clinical Centre of Serbia, Belgrade, Serbia
| | - Jecko Thachil
- Department of Haematology, Manchester University Hospitals, Manchester, UK
| | - Mirjana Mitrovic
- Clinic of Haematology, University Clinical Centre of Serbia, Belgrade, Serbia.,Faculty of Medicine, University of Belgrade, Belgrade, Serbia
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Changing profile of platelet activity and turnover indices during treatment response of immune thrombocytopenia. Clin Exp Med 2022; 22:595-603. [PMID: 35137341 DOI: 10.1007/s10238-022-00790-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 12/26/2021] [Indexed: 01/19/2023]
Abstract
Both platelet count and function change after treatment of immune thrombocytopenia. Platelet function can be measured by plasma markers, including platelet activity [e.g., soluble P-selectin (sP-selectin) and soluble CD40 ligand (sCD40L)] and platelet turnover markers [e.g., glycocalicin (GC)]. Patients were classified into no response (NR, including new diagnosis), partial response (PR) and complete response (CR). One hundred and sixteen samples (29 CR, 32 PR, 55 NR) from 79 patients were collected. Plasma markers (sP-selectin, sCD40L and GC) were measured by ELISA. Platelet counts and mean platelet volume (MPV) were obtained in the clinical laboratory using GenS System-2. The results showed that responsive patients (PR + CR) had higher levels of sP-selectin (P = 0.026) and sCD40L (P = 0.001). Although there was no difference in MPV (P = 0.077) or GC (P = 0.078), there was a marked decrease of GC index (P < 0.001) in responsive patients. Paired sample analysis showed no difference in sP-selectin, sCD40L, MPV or GC but significant difference in GC index (P = 0.017) between NR and PR. Another paired sample analysis showed no difference in sP-selectin, sCD40L, MPV or GC but significant difference in GC index (P = 0.029) between PR and CR. Patients with refractory and newly diagnosed disease had a significant difference in GC (P = 0.020) and sCD40L (P = 0.001), despite similarly low platelet counts. In conclusion, platelet activity markers (sP-selectin and sCD40L) and GC indices change in parallel with treatment response. Plasma levels of GC and sCD40L may be predictors of treatment response.
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Kuter DJ. Novel therapies for immune thrombocytopenia. Br J Haematol 2021; 196:1311-1328. [PMID: 34611885 DOI: 10.1111/bjh.17872] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 09/17/2021] [Accepted: 09/19/2021] [Indexed: 01/02/2023]
Abstract
Current therapies for immune thrombocytopenia (ITP) are successful in providing a haemostatic platelet count in over two-thirds of patients. Still, some patients have an inadequate response and there is a need for other therapies. A number of novel therapies for ITP are currently being developed based upon the current pathophysiology of ITP. Many therapies are targetted at reducing platelet destruction by decreasing anti-platelet antibody production by immunosuppression with monoclonal antibodies targetted against CD40, CD38 and the immunoproteasome or physically reducing the anti-platelet antibody concentration by inhibition of the neonatal Fc receptor. Others target the phagocytic system by inhibiting FcγR function with staphylococcal protein A, hypersialylated IgG, polymeric Fc fragments, or Bruton kinase. With a recognition that platelet destruction is also mediated by complement, inhibitors of C1s are also being tested. Inhibition of platelet desialylation may also play a role. Other novel therapies promote platelet production with new oral thrombopoietin receptor agonists or the use of low-level laser light to improve mitochondrial activity and prevent megakaryocyte apoptosis. This review will focus on these novel mechanisms for treating ITP and assess the status of treatments currently under development. Successful new treatments for ITP might also provide a pathway to treat other autoimmune disorders.
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Affiliation(s)
- David J Kuter
- Hematology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Kuter DJ, Newland A, Chong BH, Rodeghiero F, Romero MT, Pabinger I, Chen Y, Wang K, Mehta B, Eisen M. Romiplostim in adult patients with newly diagnosed or persistent immune thrombocytopenia (ITP) for up to 1 year and in those with chronic ITP for more than 1 year: a subgroup analysis of integrated data from completed romiplostim studies. Br J Haematol 2019; 185:503-513. [PMID: 30793285 PMCID: PMC6593696 DOI: 10.1111/bjh.15803] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/18/2018] [Indexed: 12/14/2022]
Abstract
The thrombopoietin receptor agonist romiplostim is approved for second-line use in chronic immune thrombocytopenia (ITP), but its effects in patients with ITP for ≤1 year are not well characterized. This analysis of pooled data from 9 studies included patients with ITP for ≤1 year (n = 311) or >1 year (n = 726) who failed first-line treatments and received romiplostim, placebo or standard of care. In subgroup analysis by ITP duration, patient incidences for platelet response at ≥75% of measurements were higher for romiplostim [ITP ≤1 year: 74% (204/277); ITP >1 year: 71% (450/634)] than for placebo/standard of care [ITP ≤1 year: 18% (6/34); ITP >1 year: 9% (8/92)]. Of patients with ≥9 months on study, 16% with ITP ≤1 year and 6% with ITP >1 year discontinued romiplostim and maintained platelet counts ≥50 × 109 /l for ≥6 months without ITP treatment (treatment-free remission). Independent of ITP duration, rates of serious adverse events and bleeding were lower with romiplostim than placebo/standard of care and thrombotic events occurred at similar rates. In this analysis, romiplostim and placebo/standard of care had similar safety profiles and romiplostim increased platelet counts in patients with either ITP ≤1 year or ITP >1 year, with more treatment-free remission in those with ITP ≤1 year.
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Affiliation(s)
- David J. Kuter
- Department of HematologyMassachusetts General HospitalBostonMAUSA
| | - Adrian Newland
- The Pathology Clinical Academic Groupthe Royal London HospitalLondonUK
| | - Beng H. Chong
- University of New South Wales and St. George HospitalSydneyAustralia
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Abstract
Thrombopoietin (TPO) is a growth factor that stimulates megakaryocytes to increases platelet counts. Due to concerns around the development of autoantibodies in clinical studies of TPO, a novel peptide that bound the TPO receptor was used to develop a TPO mimetic. This peptide has no shared homology with TPO, and therefore avoids the risk of development of antibodies that cross-react with endogenous TPO. The ability of the artificial peptide to bind and stimulate the TPO receptor was improved by dimerization of the peptide, and the stability of the peptide was improved by linking the peptides to the Fc portion of an antibody. Romiplostim (Nplate, Amgen, Inc, Thousand Oaks, CA) is the first fully engineered fusion of a novel peptide and antibody or "peptibody" that can stimulate platelet production.
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Affiliation(s)
- Allen S Yang
- Hematology/Oncology, Amgen, Inc, Thousand Oaks, CA.
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Jin C, Jia Y, Jin C, Dong H, Cheng P, Zhou J, Wang Y, Zheng B, Liu F. Therapeutic effect of Halofuginone on ITP mice by regulating the differentiation of Th cell subsets. Int Immunopharmacol 2014; 18:213-6. [DOI: 10.1016/j.intimp.2013.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 12/07/2013] [Accepted: 12/09/2013] [Indexed: 11/29/2022]
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Strom TS. A numerical analysis model for the interpretation of in vivo platelet consumption data. PLoS One 2013; 8:e55087. [PMID: 23383066 PMCID: PMC3557263 DOI: 10.1371/journal.pone.0055087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/21/2012] [Indexed: 12/18/2022] Open
Abstract
Unlike anemias, most thrombocytopenias cannot be separated into those due to impaired production and those due to accelerated consumption. While rapid clearance of labeled platelets from the bloodstream can be followed in thrombocytopenic individuals, no model exists for quantitatively inferring from autologous or allogeneic platelet consumption data what changes in random consumption, lifespan dependent consumption, and platelet production rate may have caused the thrombocytopenia. Here we describe a numerical analysis model which resolves these issues. The model applies three parameter values (a random consumption rate constant, a lognormally-distributed platelet lifespan, and the standard deviation of the latter) to a matrix comprising a series of platelet cohorts which are sequentially produced and fractionally consumed in a series of time intervals. The cohort platelet counts achieved after equilibration of production and consumption both enumerate the population age distribution and sum to the population platelet count. Continued platelet consumption after production is halted then serves to model in vivo platelet consumption data, with consumption rate in the first such interval defining the equilibrium platelet production rate. We use a least squares fitting procedure to find parameter values which best fit observed platelet consumption data obtained in WT and thrombocytopenic WASP(-) mice. Equilibrium platelet age distributions are then ‘grafted’ into the matrix to allow modeling of the consumption of WT platelets in WASP(-) recipients, and vice versa. The optimal parameter values obtained indicate that random WT platelet consumption accounts for a larger fraction of platelet turnover than was previously suspected. Platelet WASP deficiency accelerates random consumption, and a trans effect of recipient WASP deficiency contributes to this. Application of the model to clinical data will allow distinctions to be made between thrombocytopenias due primarily to impaired platelet production and those due to acceleration of random or lifespan-dependent platelet consumption.
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Affiliation(s)
- Ted S Strom
- Department of Pathology and Laboratory Medicine, Memphis Veterans Administration Medical Center, Memphis, TN, USA.
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