Eltrombopag may induce bone marrow fibrosis in allogeneic hematopoietic stem cell transplant recipients with prolonged thrombocytopenia

Adjunctive effects of eltrombopag on immunosuppressive therapy for childhood aplastic anemia

Eltrombopag is used with first-line immunosuppressive therapy for adult aplastic anemia, although its practical utility in childhood remains unclear. We retrospectively analyzed the outcomes of pediatric patients who received eltrombopag in Japan. Of the 27 eligible patients, 23 (85%) were previously treated, and 15 (56%) had severe or very-severe disease. Seventeen (63%) received eltrombopag with or after rabbit anti-thymocyte globulin plus cyclosporin-A. Within the first year of eltrombopag therapy, 12 patients showed a good or partial response, 15 showed no response, and 8 non-responders successfully underwent hematopoietic cell transplantation. Within the first 3 months after eltrombopag therapy, all but one of the transfusion-dependent responders became transfusion-independent. At 12 months, 6 of 12 responders were disease-free off-treatment. The one-year overall response rate was higher for severe or very-severe than non-severe cases (p = 0.006). Multivariable analysis showed that very-severe disease at the start of eltrombopag therapy was a predictor of being disease-free off-treatment (p = 0.03). No cytogenetic abnormalities developed, but myelofibrosis occurred 4 months after eltrombopag therapy in one non-responder with very-severe disease. The first 3 months' response to adjunctive eltrombopag may guide to the safe and effective use for the cure of disease, although prospective trials are needed to determine its long-term effects.

Let It Grow: The Role of Growth Factors in Managing Chemotherapy-Induced Cytopenia

Chemotherapy-induced cytopenia (CIC) is characterized by neutropenia, anemia, and thrombocytopenia, which are common and serious complications in cancer treatment. These conditions affect approximately 60% of patients undergoing chemotherapy and can significantly impact quality of life, treatment continuity, and overall survival. The use of growth factors, including granulocyte colony-stimulating factors (GCSFs), erythropoietin-stimulating agents (ESAs), and thrombopoietin receptor agonists (TPO-RAs), has emerged as a promising strategy for managing CIC. However, the use of these growth factors must be approached with caution. This review provides an overview of the mechanisms, efficacy, and safety of growth factors in the management of CIC. Additionally, we discuss predictive markers for treatment response, potential risks, and highlight areas for future research.

Thrombopoietin Receptor Agonists in Post-Hematopoietic Cell Transplantation Complicated by Prolonged Thrombocytopenia: A Comprehensive Review

Hematopoietic cell transplantation (HCT) is a well-established procedure that has become a therapeutic mainstay for various hematological conditions. Prolonged thrombocytopenia following HCT is associated with a significant risk of morbidity and mortality, yet no universally recognized treatment protocol exists for such a complication. First-generation thrombopoietin receptor (TpoR) agonists as well as second-generation agents are known for their role in enhancing platelet production, and their use is expanding across various thrombocytopenic conditions. Therefore, we conducted this comprehensive review of the literature to provide an updated evaluation of the use of TpoR agonists and explore their efficacy and safety in the treatment of extended post-HCT thrombocytopenia. The literature search was conducted using PubMed database from 1996 through December 2023, using a predefined strategy with medical subject headings terms. We identified 64 reports on the utility of TpoR agonists, five of them were randomized controlled trials and the rest were retrospective observational studies and case series, with a total number of 1730 patients. Second-generation TpoR agonists appear more convenient than subcutaneous recombinant human thrombopoietin (rhTpo) as they can be orally administered and exhibit similar efficacy in platelet recovery, as indicated by recent trial results. Among these agents, avatrombopag, unlike eltrombopag, does not require any dietary restrictions, which could be more favorable for patients. However, eltrombopag remains the most extensively studied agent. TpoR agonists had promising effects in the treatment of post-HCT thrombocytopenia with a good safety profile so far, highlighting the potential benefit of their use.

Management of chemotherapy-induced thrombocytopenia: guidance from the ISTH Subcommittee on Hemostasis and Malignancy

Thrombocytopenia is a common adverse effect of chemotherapy. The development of chemotherapy-induced thrombocytopenia (CIT) is influenced by cancer type and therapy, occurring in approximately one-third of patients with a solid tumor diagnosis and half of all patients with a hematologic malignancy. CIT may complicate the administration of chemotherapy, leading to therapeutic delays or dose reductions. This guidance document, presented by the International Society on Thrombosis and Haemostasis (ISTH) Subcommittee on Hemostasis and Malignancy, provides a comprehensive summary of the evidence and offers direction on the use of thrombopoietin receptor agonists (TPO-RAs) in various settings of CIT, including solid tumors, acute myeloid leukemia, stem cell transplant, and lymphoma. Studies have shown that TPO-RAs can improve platelet counts in CIT, but the clinical benefits of TPO-RA in terms of reducing bleeding, limiting platelet transfusion, avoiding chemotherapy delay, or dose reduction are uncertain. Further research is needed to optimize the selection of appropriate indications and study design to manage thrombocytopenia following chemotherapy.

Definitions, incidence and outcome of poor graft function after hematopoietic cell transplantation: A systematic review and meta-analysis

Poor graft function (PGF) after allogeneic hematopoietic stem cell transplantation (HCT) is a serious complication with high morbidity and mortality. The reported incidence of PGF, its risk factors and outcome vary substantially between studies. This variability may be explained by heterogeneity in patient cohorts and HCT strategies, differences in the underlying causes of cytopenia, as well as by differences in PGF definition. In this systematic review and meta-analysis, we provide an overview of the various PGF definitions used and determined the impact of this variability on the reported incidence and outcome. We searched MEDLINE, EMBASE and Web of Science up to July 2022, for any study on PGF in HCT recipients. We performed random-effect meta-analyses for incidence and outcome and subgroup analyses based on different PGF criteria. Among 69 included studies (14.265 HCT recipients), we found 63 different PGF definitions, using various combinations of 11 common criteria. The median incidence of PGF was 7% (IQR: 5-11%, 22 cohorts). The pooled survival of PGF patients was 53% (95% CI: 45-61%, 23 cohorts). The most commonly reported risk factors associated with PGF were history of cytomegalovirus infection and prior graft-versus-host disease. Incidence was lower in studies with strict cytopenic cutoffs, while survival was lower for primary compared to secondary PGF. This work indicates that a standardized, quantitative definition of PGF is needed to facilitate clinical guideline development and to advance scientific progress.