Eltrombopag for the treatment of poor graft function following allogeneic stem cell transplant: a retrospective multicenter study

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.

2024 update on allogeneic hematopoietic stem cell transplant for myelofibrosis: A review of current data and applications on risk stratification and management

BACKGROUND

Allogeneic hemopoietic stem cell transplantation (HSCT) currently remains the only curative treatment for patients with myelofibrosis (MF). Transplant related mortality (TRM) and relapse, remain two significant complications which need to be addressed.

AIMS

The aim of this manuscript is to review current available reports on changes which have recently occurred, to improve the outcome of MF patients undergoing an allogeneic HSCT.

METHODS

Published papers were used to analyze different aspects of allogeneic HSCT.

RESULTS

Changes and updates are provided on selection of patients, prognostic systems, managing splenomegaly, conditioning regimens, predicting transplant outcome, stem cell sources, stem cell donors, graft versus host disease (GvHD) prophylaxis, patients with blast phase, hematopoietic reconstitution, disease markers, donor chimerism, and treatment of relapse.

CONCLUSIONS

The review outlines new transplant platforms which are now available for patients with myelofibrosis, together with persisting problems, among which, older age combined with marrow fibrosis and an inflammatory disease. Relapse also requires aggressive monitoring of drivers mutations, and early cellular therapy.

Eltrombopag treatment in thrombocytopenia following hematopoietic stem cell transplantation: A multicenter real-world experience

INTRODUCTION

Thrombocytopenia is among the most common complications following hematopoietic stem cell transplantation and is associated with increased mortality and morbidity with no standard treatment yet. In this multicenter and retrospective study, we aim to present our multi-center experience of Eltrombopag treatment in patients with isolated thrombocytopenia following HSCT.

MATERIAL-METHOD

A total of 73 patients from 5 centers who underwent autologous or allogeneic stem cell transplantation, had no primary disease relapse, all of whom had neutrophil engraftment, complete chimerism, and who were diagnosed with Prolonged Isolated Thrombocytopenia (PIT) or Secondary Failure Of Platelet Recovery (SFPR) were included in the study. The patients were initiated on Eltrombopag at a dose of 50-150 mg. Complete response was defined as a platelet count >50×109/L for 7 consecutive days with no transfusion support.

RESULTS

A total of 50.3% of the patients underwent Autologous and 49.7% Allogeneic Stem Cell Transplantation, 54.8% were diagnosed with PIT, and 45.2% were diagnosed with SFPR, and the treatment with 50-150 mg/day Eltrombopag was initiated on the median day +42. Complete response was achieved in 71.2% of these patients on the median day 23 of the treatment. No significant effects of the initial dose (50-150 mg/day) were detected in the Complete Response in the multivariate analysis on response. An insufficient number of Megakaryocytes in the bone marrow before Eltrombopag treatment was determined as an independent risk factor in determining the response (OR 3.57, 95% CI 1.21-10.55). The overall survival of the patients who did not respond to Eltrombopag was found to be significantly worse than that of patients who responded (p=0.022, HR:2.74, 95% CI 1.12-6.54).

CONCLUSION

As a result of the present study, Eltrombopag treatment was found to be effective and safe in thrombocytopenia that develops following hematopoietic stem cell transplantation. It was concluded that its use may be more effective in patients with sufficient bone marrow megakaryocytes before the treatment and an initial dose of 50 mg/day may be appropriate in terms of cost, effectiveness, and toxicity. Large-scale randomized and controlled prospective studies are needed to determine the roles of Eltrombopag treatment in patients with post-transplant PIT and SFPR.

Hematopoiesis and immune reconstitution after CD19 directed chimeric antigen receptor T-cells (CAR-T): A comprehensive review on incidence, risk factors and current management

Impaired function of hematopoiesis after treatment with chimeric antigen T-cells (CAR-T) is a frequent finding and can interest a wide range of patients, regardless of age and underlying disease. Trilinear cytopenias, as well as hypogammaglobulinemia, B-cell aplasia, and T-cell impairment, can severely affect the infectious risk of CAR-T recipients, as well as their quality of life. In this review, we provide an overview of defects in hematopoiesis after CAR-T, starting with a summary of different definitions and thresholds. We then move to summarize the main pathogenetic mechanisms of cytopenias, and we offer insight into cytomorphological aspects, the role of clonal hematopoiesis, and the risk of secondary myeloid malignancies. Subsequently, we expose the major findings and reports on T-cell and B-cell quantitative and functional impairment after CAR-T. Finally, we provide an overview of current recommendations and leading experiences regarding the management of cytopenias and defective B- and T-cell function.

Outcomes of cesarean delivery in placenta accreta: conservative delivery vs. cesarean hysterectomy

OBJECTIVES

To compare delivery outcomes of pregnancies diagnosed with placenta-accreta-syndrome (PAS) who underwent conservative treatment to patients who underwent cesarean hysterectomy.

METHODS

A retrospective study of all women diagnosed with PAS treated in one tertiary medical center between 03/2011 and 11/2020 was performed. Comparison was made between conservative management during cesarean delivery and cesarean hysterectomy. Conservative management included leaving uterus in situ with/without placenta and with/without myometrial resection.

RESULTS

A total of 249 pregnancies (0.25 % of all deliveries) were diagnosed with PAS, 208 underwent conservative cesarean delivery and 41 had cesarean hysterectomy, 31 of them were unplanned (75.6 %). The median number of previous cesarean deliveries was significantly higher in the cesarean hysterectomy group. There was no difference in the duration from the last cesarean delivery, the presence of placenta previa, pre-operative hemoglobin or platelets levels between the pregnancies with conservative management and the cesarean hysterectomy. Significantly more pregnancies with sonographic suspicion of placenta percreta and bladder invasion had cesarean hysterectomy. Cesarean hysterectomy was significantly associated with earlier delivery, with bleeding and required significantly more blood products. There was no statistically significant difference in the rate of relaparotomy following cesarean delivery or the rate of infections. Multivariable-regression-analysis revealed a significant odds ratio of 3.38 of blood loss of >3,000 mL following cesarean hysterectomy.

CONCLUSIONS

Conservative management in delivery of PAS pregnancies is associated with less bleeding complications during surgery compared to cesarean hysterectomy.

Knowledge map of thrombopoietin receptor agonists: A bibliometric analysis

Thrombopoietin receptor agonists (TPO-RAs) have been widely used to treat thrombocytopenia, however, a scientometric profile of TPO-RAs research is lacking. Methods: This study uses VOSviewer, CiteSpace, and R software to provide an overview of current research, highlight study hotspots, and predict future research directions of TPO-RAs. Results: One thousand seven hundred and nineteen relevant studies from 1993 to 2022 with 43962 citations were identified from the Web of Science Core Collection. Over three decades, the USA has been leading TPO-RAs publications. Industries and academic institutions have been actively involved in TPO-RAs research, with funding provided by pharmaceutical companies and public funding bodies. The most productive and cited journals are British Journal of Hematology and Blood, respectively. When author keywords were categorised into three clusters, i.e., cluster 1 (immune thrombocytopenic purpura (ITP)), cluster 2 (avatrombopag, lusutrombopag, and thrombocytopenia), and cluster 3 (TPO-RAs for ITP and off-label drug use), ITP was found to be the current research hotspot, while oral TPO-RAs and licensed or unlicensed drug indications of thrombocytopenic diseases require further investigation. Conclusion: This study has generated the knowledge map of TPO-RAs, which provides a dynamic roadmap for future research in this field.

Placental expanded mesenchymal-like cells (PLX-R18) for poor graft function after hematopoietic cell transplantation: A phase I study

Persistent cytopenia in the post-hematopoietic cell transplantation (HCT) setting can occur despite adequate engraftment of donor cells. PLX-R18, a placental-derived mesenchymal-like cell product, is expanded ex vivo in a 3-dimensional environment. PLX-R18 cells secrete a large array of hematopoietic factors, which promote regeneration, maturation, and differentiation of hematopoietic cells and stimulate their migration to peripheral blood. This phase 1, first-in-human study (NCT03002519), included 21 patients with incomplete hematopoietic recovery post-HCT. Patients were treated with escalating doses of PLX-R18: 3 patients received 1 million cells/kg, 6 received 2 million cells/kg, and 12 received 4 million cells/kg via multiple intramuscular injections. While patients received only two administrations of cells during the first week, peripheral blood counts continued to increase for months, peaking at 6 months for hemoglobin (Hb, p = 0.002), lymphocytes (p = 0.008), and neutrophils (ANC, p = 0.063), and at 9 months for platelets (p < 0.001) and was maintained until 12 months for all but ANC. The need for platelet transfusions was reduced from 5.09 units/month at baseline to 0.55 at month 12 (p = 0.05). Likewise, red blood cell transfusions decreased from 2.91 units/month at baseline to 0 at month 12 (p = 0.0005). PLX-R18 was safe and well tolerated and shows promise in improving incomplete hematopoietic recovery post-HCT.

Eltrombopag for the Treatment of Allogeneic Hematopoietic Stem Cell Transplantation-Related Poor Graft Function

INTRODUCTION

Allogeneic stem cell transplantation (ASCT) is a crucial therapeutic strategy for hematological and non-hematological disorders. Poor graft function (PGF) after ASCT presents a critical challenge that does not have a standardized treatment approach. A thrombopoietin-mimetic oral drug eltrombopag shows promise in some bone failure syndromes. This study aimed to analyze the efficacy of eltrombopag in treating PGF after ASCT.

METHODS

Patients receiving eltrombopag for PGF after ASCT between 2017 and 2020 were retrospectively evaluated. Patients' characteristics, details for ASCT, timing, treatment, and possible contributors for PGF, response to eltrombopag treatment, and overall response rate (ORR) were analyzed.  Results: Eighteen patients were assessed. Eltrombopag treatment yielded a favorable response in 11 patients, resulting in an ORR of 61%. The ORR in secondary PGF was better than that in primary PGF (83% and 17% respectively). There was a marked enhancement in platelet and hemoglobin levels following eltrombopag treatment (p=0.001 and p=0.030, respectively), while neutrophil values exhibited no significant change (p=0.8). Among the responding patients, four individuals (22%) underwent a tapering and discontinuation of eltrombopag. No toxicity was observed above grade one, and no patient discontinued eltrombopag because of intolerability or adverse events.

CONCLUSION

Our findings affirm that eltrombopag can treat poor graft function after allogeneic stem cell transplantation without significant toxicities. These results contribute to the growing body of evidence supporting the use of eltrombopag in poor graft function after allogeneic stem cell transplantation, providing insights into its potential benefits and limitations.

Poor graft function after haploidentical stem cell transplantation with post-transplant cyclophosphamide

This is a retrospective cohort study of consecutive adult patients who received a haploidentical-SCT (haplo-SCT) with post-transplant cyclophosphamide (PT-Cy) in a single centre. Poor graft function (PGF) was defined as the occurrence of either persistent neutropenia (ANC < 0.5 × 10⁹/µL) with poor response to granulocyte colony-stimulating factors (G-CSF) and/or thrombocytopenia (platelets < 20 × 10⁹/L) with transfusion dependence, with complete donor chimerism and without concurrent severe GVHD or underlying disease relapse, during the first 12 months after transplantation. Forty-four (27.5%) out of 161 patients were diagnosed with PGF. Previous CMV reactivation was significantly more frequent in patients with PGF (88.6% versus 73.5%, p = 0.04) and the number of reactivations was also higher in these patients. Besides, early CMV reactivations in the first 6 months post-SCT were also significantly more frequent among patients with PGF (88.6% versus 71.8% p = 0.025). Thirty-two percent of patients with PGF were treated with increasing doses of thrombopoietin-receptor agonists (TRA) and 7 patients were treated with a donor CD34 + selected boost. In total, 93.2% of patients reached adequate peripheral blood counts in a median time of 101 days (range 11-475) after diagnosis. PGF is a frequent complication after haplo-SCT with PT-Cy. CMV reactivation might be the most relevant factor associated to its development. Even when most patients recover peripheral counts with support therapy, there is a group of patients with persistent cytopenias who can effectively be treated with TRA and/or a boost of CD34 + selective cells.

Graft failure in allogeneic hematopoietic stem cell recipients: diagnosis and treatment

Graft failure is a group of complications after allogeneic hematopoietic stem cell transplantation, which occurs according to different data up to 30%. The group of complications includes primary and secondary graft failure, primary, secondary and transient poor graft function and graft rejection. Diagnostic difficulties consist in the lack of unified diagnostic criteria accepted in the transplantation community and in the dual interpretation of these complications according to the foreign literature. The purpose of this literature review was to identify the most common criteria of different types of graft failure and determine the tactics of diagnosis and treatment. In this review we analyzed data from various literature sources, gave definitions of graft failure and poor graft function. We analyzed the literature data on the methods used to treat these conditions.

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

Poor graft function (PGF) and secondary failure of platelet recovery (SFPR) are significant causes of transplant related morbidity and mortality. Although thrombopoietin receptor agonists (TPO-RA), particularly Eltrombopag (EPAG), have been reported to be efficacious in the treatment of prolonged thrombocytopenia, potential long term adverse effects remain to be elucidated. This retrospective study was performed to determine the efficacy and toxicity profile of TPO-RAs in allogeneic hematopoietic stem cell transplant (alloHCT) recipients. Medical records of 27 patients [median age: 55(21-73) years; male/female: 15/12] who received posttransplant EPAG for SFPR or PGF were analysed. Eltrombopag was started on day 110(33-670) after transplant. Median initial dose was 25(25-50) mg/day which was properly escalated to a maximum dose of 75(50-100) mg/day. Duration of the treatment was median 120(31-377) days. Overall response rate (ORR) was 59.3% in the study population. Time-to-treatment response was 42(3-170) days. Mild-to-moderate bone marrow fibrosis was detected in the posttreatment biopsies of 12/22 patients (54.5%), 9 of whom did not represent any grade of myelofibrosis in their inital biopsies. The grade of posttreatment fibrosis was significantly increased when time-to-treatment response was longer (p = 0.008). Long term use of TPO-RAs may be considered as a potential cause of myelofibrosis in alloHCT recipients.

Efficacy and Immunomodulating Properties of Eltrombopag in Aplastic Anemia following Autologous Stem Cell Transplant: Case Report and Review of the Literature

Thrombopoietin receptor agonists (TPO-RA) are currently indicated for the treatment of chronic immune thrombocytopenia and relapsed refractory aplastic anemia. However, the off-label use of these drugs is more and more frequent, including in the setting of aplasia secondary to chemotherapy and hemopoietic stem cell transplant (SCT). Growing evidence suggests that mechanisms of action of TPO-RA go beyond the TPO-receptor stimulation and point at the immunomodulating properties of these drugs. Here, we present a case of prolonged bone marrow aplasia secondary to autologous SCT treated with eltrombopag. We describe the clinical efficacy and the immunomodulating effect of this drug on inflammatory cytokine profile and bone marrow histology. Furthermore, we provide a review of the most recent literature highlighting the efficacy and safety of TPO-RA after SCT and chemotherapy for hematologic conditions.

Thrombocytopenia and Therapeutic Strategies after Allogeneic Hematopoietic Stem Cell Transplantation

Thrombocytopenia following allogeneic hematopoietic stem cell transplantation is a usual complication and can lead to high morbidity and mortality. New strategies, such as the use of another graft versus host-disease prophylaxis, alternative donors, and management of infections, have improved the survival of these patients. The mechanisms are unknown; therefore, the identification of new strategies to manage this potentially serious problem is needed. Thrombopoietin receptor agonists are currently available to stimulate platelet production. Some small retrospective studies have reported their potential efficacy in an allogeneic stem cell transplant setting, confirming good tolerability. Recent studies with higher numbers of patients also support their safety and efficacy in this setting, hence establishing the use of these drugs as a promising strategy for this post-transplant complication. However, prospective trials are needed to confirm these results.

2021 Update on allogeneic hematopoietic stem cell transplant for myelofibrosis: A review of current data and applications on risk stratification and management

The number of patients with myelofibrosis (MF) undergoing an allogeneic hemopoietic stem cell transplantation (HSCT) is increasing: in the analysis of the European Group for Blood and Marrow Transplantation (EBMT) the number of MF has increased from 515 in 2014 to 748 in 2018 . This reflects the fact that HSCT is currently the only curative treatment, capable of inducing prolonged disease‐free survival. Nevertheless, several problems prevent more patients from undergoing an allogeneic HSCT: we will be discussing indications for HSCT, comorbidities, splenomegaly, older age and disease phase. Donor type and stem cell source are less of a problem. Several transplant platforms exist, including different strategies for graft versus host disease (GvHD) prophylaxis, Age tailored conditioning regimens need to be implemented, to allow older and fragile patients to undergo an allogeneic HSCT.