Efficacy and safety of thrombopoietin receptor agonists in solid tumors with chemotherapy-induced thrombocytopenia: a meta-analysis.

OBJECTIVE: To evaluate the efficacy and safety of thrombopoietin receptor agonists (TPO-RAs) in solid tumors with chemotherapy-induced thrombocytopenia (CIT). METHODS: We conducted a comprehensive search of PubMed, FMRS, Cochrane Library, Web of Science, EMBASE, and ClinicalTrials.gov for randomized controlled trials (RCTs) reporting the efficacy and safety of TPO-RAs in solid tumors with CIT. The search was limited to articles published before April 30, 2022. Primary outcomes included chemotherapy dose reduction or delays, platelet transfusion, the incidence of grade 3 or 4 thrombocytopenia, and bleeding events. Secondary outcomes encompassed the incidence of platelet count > 400 × 109/L, adverse events (AEs), serious AEs, thrombosis, and mortality. RESULTS: Our analysis encompassed six studies: five rigorous RCTs and one unique study comparing romiplostim to an observation group, involving a total of 489 patients. For primary outcomes, TPO-RAs significantly reduced the incidence of grade 3 or 4 thrombocytopenia (RR = 0.69, 95% CI: 0.52-0.91). After applying the Bonferroni correction for multiple comparisons, the significance of the reduction in grade 3 or 4 thrombocytopenia incidence persisted (P = 0.008). TPO-RAs showed no significant impact on chemotherapy dose reduction or delays (RR = 0.81, 95% CI: 0.65-1.01), platelet transfusion (RR = 1.04, 95% CI: 0.48-2.27), or bleeding events (RR = 0.50, 95% CI: 0.23-1.10). In terms of safety, there were no significant difference in the incidence of any AEs (RR = 0.98, 95% CI:0.92-1.04), serious AEs (RR = 0.79, 95% CI:0.45-1.40), thrombotic events (RR = 1.20, 95% CI:0.51-2.84) and mortality (RR = 1.15, 95% CI:0.55-2.41). CONCLUSIONS: This meta-analysis suggests that TPO-RAs are generally well-tolerated. However, their efficacy in solid tumors with CIT appears limited, as they only demonstrate a reduction in the incidence of grade 3 or 4 thrombocytopenia.

Thrombopoietin receptor agonists for refractory thrombocytopenia in patients after autologous hematopoietic stem cell transplantation.

OBJECTIVE: Autologous hematopoietic stem cell (ASC) transplantation (ASCT) is an effective treatment method for patients with hematological disorders and malignant diseases. The patient's ASCs are harvested prior to radiotherapy/chemotherapy, cryopreserved and then transfused back after the high-dose radiotherapy/chemotherapy conditioning treatment. Since some patients develop thrombocytopenia after receiving ASCT, it is difficult for them to bear simultaneously the management of their original disease and thrombocytopenia. The present study aimed to evaluate the efficacy and safety of thrombocytopenia therapy with thrombopoietin receptor agonists (TPORAs) after ASCT. METHODS: We retrospectively analyzed the clinical safety and efficacy of TPORA treatment for the enrolled 20 patients who developed thrombocytopenia after ASCT. The measured parameters were prolonged isolated thrombocytopenia (PIT), secondary failure of platelet recovery (SFPR) and other calculated response index. Patients with platelet count (PC) ≤ 50×109/L were treated with TPORA, namely with either eltrombopag (Elt), hetrombopag (Het), or avatrobopag (Ava). RESULTS: The group of 20 patients, who received TPORA administration for their thrombocytopenia after ASCT, had a median age of 50 years (ranging between 17 and 60 years). The median administration time of TPORA application was 48 days (ranging from 7 to 451 days); an overall response rate (ORR) was 85% with no response in 15% of patients, while with complete response (CR) in 70% of patients and partial response (PR) in 15% of patients. The median platelet count was 19 × 109/L before TPORA treatment and increased to 87×109)/L after the treatment. The TPORA treatment was safe as only 4 patients (20%) displayed a mild transaminase elevation. No other reported side effects occurred, such as thrombosis, joint pain, diarrhea, and myelofibrosis. It was demonstrated that the short response time to TPORA treatment correlated to the fast platelet recovery, when the number of megakaryocytes in the bone marrow smear exceeded 35/4.5 cm2 under a low magnification of 100 times (p = 0.015). CONCLUSION: TPORA therapy for thrombocytopenia occurring after the radiotherapy/ chemotherapy-conditioned ASCT was well tolerated and effective for platelets recovery.

Thrombopoietin Receptor Agonists for Thrombocytopenia Secondary to HER2-Targeted Antibody Drug Conjugates.

Trastuzumab emtansine and trastuzumab deruxtecan are widely used in breast cancer and other solid tumor malignancies. Thrombocytopenia is a common adverse event associated with the use of these agents that can lead to a treatment delay, reduction in dose intensity, and discontinuation. The role of thrombopoietin receptor agonists (TPO-RA) remains unknown in this setting. We report a case series of 6 individuals with breast cancer that experienced dose-reductions and therapy delays due to thrombocytopenia secondary to trastuzumab emtansine or trastuzumab deruxtecan therapy and received intervention with TPO-RA. All 6 were able to resume therapy with TPO-RA support.

Investigational drugs for immune thrombocytopenia.

INTRODUCTION: Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease of unknown cause. Autoantibodies, self-reactive T cells and other immune abnormalities, with impairment of platelet production, lead to a reduced platelet count. Until recently, therapy was largely empirical using immune suppressants (none of which have undergone randomized clinical trials). These therapies have variable efficacy and are associated with predictable unwanted effects which impact patient quality-of-life. With greater understanding of the underlying pathophysiology, better, more targeted therapies have been developed; however, there is still an urgent need for additional classes of treatment. AREAS COVERED: This article covers new TPO receptor agonists, Syk inhibitors, Fcγ receptor antagonists, BTK and complement inhibitors, and other therapies. Insights into the most promising therapies are offered. Novel ITP treatments currently in clinical trials and those recently approved come under the spotlight. EXPERT OPINION: Thrombopoietin receptor agonists remain the most effective treatment for ITP and have changed the ITP therapeutic landscape remarkably. Other new molecules such as Fcγ receptor blockers, Bruton tyrosine kinase, complement inhibitors, and others are unlikely to enjoy the same success rate as the TPO-RAs, but nonetheless they will find a place in the management of patients with ITP.

Eltrombopag improves refractory thrombocytopenia in patients with Sjögren's syndrome.

INTRODUCTION: Eltrombopag, a kind of thrombopoietin (TPO) receptor agonist, plays the role on the megakaryocyte to activate the platelet production and rapidly increase the number of circulating platelets in patients with primary immune thrombocytopenia (ITP). Eltrombopag provides an opportunity for rapid tapering and/or cessation of corticosteroid therapy. However, it is not clear about the platelet response to Eltrombopag in ITP associated with Sjögren's Syndrome(SS). METHODS: A retrospective research was conducted on the clinical course of three patients, each with ITP secondary to SS, and initially received therapy of corticosteroids or other immunomodulatory. They took this drug for bleeding diseases. Referring to the description, Eltrombopag was prescribed and adjusted with an initial dose of 25 mg daily, then weekly, then monthly according to the monitoring of platelet counts. RESULTS: All patients maintained a satisfactory level of platelet counts (>100,000/mm3 for >2 years) following corticosteroid withdrawal. Meanwhile, Eltrombopag was well-tolerated, and there were no adverse effects, such as thrombotic events. CONCLUSIONS: Eltrombopag is effective and safe for patients with ITP associated with SS during corticosteroid withdrawal. Thus it may be a crucial therapeutic strategy for reducing corticosteroid-related side effects in SS patients with ITP.

Risk of thrombosis with thrombopoietin receptor agonists for ITP patients: A systematic review and meta-analysis.

One possible side effect of thrombopoietin receptor agonists in immune thrombocytopenia is thrombosis. Our aim is to systematically review whether patients with ITP that were treated with a TPO-RA have an increased risk for thrombosis as compared to ITP patients without TPO-RA. Patients in the intervention group were required to receive TPO-RA therapy. The primary outcome was the incidence of thromboembolic events. Eleven studies were included in the pooled analysis. More thromboembolic events were noted in the TPO-RA group than in the control group: 25 compared to 4. Ten out of 11 studies showed a relative risk greater than 1. However, none of these individual risk ratios was statistically significant. The meta-analysis showed a RR of 1.82 [95 % CI 0.78-4.24]. Our findings indicate there is a non-significant higher chance of thrombosis in ITP patients with TPO-RA treatments versus ITP patients without TPO-RA treatment.

Characterization and prognosis of temozolomide-induced aplastic anemia in patients with central nervous system malignancies.

BACKGROUND: Temozolomide-induced aplastic anemia (TIAA) is a rare but highly challenging complication of temozolomide (TMZ) therapy. Evidence describing prognosis, clinical characteristics, and treatment of this entity is very limited. METHODS: We performed a multicenter, 22-year observational cohort study of patients with central nervous system (CNS) malignancies treated with temozolomide who developed TIAA, retrospectively analyzing prognosis, complications, and recovery. TIAA was defined using adapted evidence-based severe aplastic anemia criteria incorporating profound cytopenias and a minimum duration (4 weeks) without hematologic recovery. RESULTS: Of 3821 patients with CNS malignancies receiving TMZ, 34 patients (0.89%) met criteria for TIAA. Onset was rapid, with 29 patients (85.3%) developing TIAA before completing a second TMZ cycle. 23 patients (67.6%) ultimately achieved a hematologic recovery. Patients without recovery were more likely to develop febrile neutropenia (72.7% vs. 30.4%, P = .03), infectious complications (45.5% vs. 8.7%, P = .02), require hospitalization (81.8% vs. 43.5%, P = .04), and die (100.0% vs. 60.9%, P = .02). Median overall survival from TIAA diagnosis was 752 days in patients achieving a partial hematologic recovery versus 28 days in those who did not (P < .0001). 29 patients (85.3%) received one or more hematopoietic growth factors; hematologic recovery rates were higher in patients receiving thrombopoietin receptor agonists (81.8% vs. 60.9%) but were not higher in patients receiving granulocyte colony-stimulating factors. CONCLUSIONS: TIAA occurs in <1% of patients receiving TMZ for CNS malignancies, but is highly morbid when it occurs and frequently fatal in the one-third of patients not achieving hematologic recovery. Thrombopoietin receptor agonists may improve the likelihood of a hematologic recovery.

Use of Thrombopoietin Receptor Agonists in Pregnancy: A Review of the Literature.

The management of immune thrombocytopenic purpura (ITP) involves several lines of therapy such as corticosteroids and intravenous immunoglobulin. With the emergence of novel therapies such as thrombopoietin receptor agonists (TPO-RAs), there has been a shift in treatment modalities. Eltrombopag and romiplostim have proven to be effective in the management of ITP through clinical studies, but their safety in pregnancy remains uncertain. The purpose of the study is to review the literature to evaluate the safety of TPO-RAs in pregnant women. Ten case reports and a cohort study pertaining to the use of TPO-RAs in pregnancy were obtained. According to the reported cases and prospective study, the use of eltrombopag and romiplostim appears to be relatively safe in the first, second, and third trimesters, as there were no reported congenital malformations. Low fetal birth weight has been observed following the administration of eltrombopag during the second trimester, whereas preterm birth has occurred following the administration of eltrombopag in the third trimester. Eltrombopag and romiplostim seem relatively safe. Further studies are necessary to clarify their safety during pregnancy.

Thrombopoietin receptor agonists for acquired thrombocytopenia following anti-CD19 CAR-T-cell therapy: a case report.

Chimeric antigen receptor (CAR)-modified T-cells targeting CD19 represent a promising therapy for relapsed or refractory (r/r) lymphoma and leukemia. The most common adverse events are immune related and include cytokine release syndrome and neurotoxicity. However, early and late hematological toxicity has emerged as a substantial clinical hurdle leading among others to an increased risk for infections or bleeding. The underlying pathophysiology remains elusive and supportive measures comprise stem cell support or the use of growth factors. Here, we report a 66-year-old woman with r/r diffuse large B-cell lymphoma that received anti-CD19 CAR-T-cells achieving a complete metabolic remission. At month 3 after adoptive cell transfer, the patient still exhibited a grade 3 anemia and a grade 4 thrombocytopenia. The latter required regular platelet transfusions. Bone marrow smear revealed hypocellularity without dysplasia. Despite reduced megakaryopoiesis, immature platelet fraction was elevated indicating an at least partially consumptive underlying component. Based on the successful use of Romiplostim, a thrombopoietin receptor-agonist, in aplastic anemia and immune thrombocytopenia, we treated our patient accordingly. Platelet count (and hemoglobin levels) increased and the patient remains transfusion-free. Taken together, our therapeutic approach could represent a novel strategy for managing CAR-T-cell-related hematotoxicity but, self-evidently, requires further controlled clinical studies.

Agonistas del receptor de trombopoyetina (Eltrompopag) para la púrpura trombocitopénica idiopática crónica en adultos y niños / Thrombopoietin receptor agonists (Eltrompopag) for chronic idiopathic thrombocytopenic purpura in adults and children

TECNOLOGÍA EVALUADA: Eltrombopag. DESCRIPCION DE LA INTERVENCIÓN: Eltrombopag (Revolade, GlaxoSmithKline) aumenta la producción de plaquetas activando el receptor de trombopoyetina, estimulando así la producción de plaquetas y reduciendo el sangrado. Eltrombopag tiene una autorización de comercialización de ANMAT para tratamiento de 'púrpura trombocitopénica inmune crónica (idiopática) (PTI) en pacientes de 1 año o más que son refractarios a otros tratamientos (p. ej. corticosteroides, inmunoglobulinas y esplenectomía). BUSQUEDA BIBLIOGRÁFICA: Se realizaron búsquedas en MEDLINE (desde 1950 hasta marzo de 2011), EMBASE (desde 1974 hasta marzo de 2019), y en el Registro Cochrane Central de Ensayos Controlados (Cochrane Central Register of Controlled Trials, CENTRAL) (Cochrane Library 2011, Número 3), para identificar todos los metaanálisis y ensayos con asignación aleatoria sobre la PTI crónica. RESULTADOS: Se incluyeron seis ensayos con 808 pacientes. Cinco estudios compararon los agonistas de receptores de TPO con placebo (romiplostim: 100, eltrombopag: 299, placebo: 175); un estudio comparó los agonistas de receptores de TPO con la atención estándar (AE) (romiplostim: 157; AE: 77). La AE incluyó una variedad de tratamientos, como glucocorticoide, inmunoglobulina anti-D, inmunoglobulina intravenosa, rituximab, azatioprina, etcétera. La supervivencia general, una de nuestras medidas de resultado primarias, no fue estudiada por estos ECAs y no fue posible calcular el número necesario a tratar (NNT). Otra medida de resultado primaria, la mejoría en los eventos de hemorragia significativa, no reveló ninguna diferencia significativa entre el grupo de agonistas de receptores de TPO y el grupo de control (placebo o AE) (versus cociente de riesgos [CR] del placebo 0,48, intervalo de confianza [IC] del 95%: 0,20 a 1,15; versus CR de la AE 0,49, IC del 95%: 0,15 a 1,63). En cuanto a las medidas de resultado secundarias, los agonistas de receptores de TPO mejoraron de forma estadísticamente significativa la respuesta plaquetaria general (versus CR del placebo 4,06, IC del 95%: 2,93 a 5,63; versus CR de la AE 1,81, IC del 95%: 1,37 a 2,37), la respuesta completa (versus CR del placebo 9,29; IC del 95%: 2,32 a 37,15) y la respuesta duradera (versus CR del placebo 14,16; IC del 95%: 2,91 a 69,01). Hubo una reducción significativa en los eventos de hemorragia general (grado 1 a 4 de la OMS) en comparación con el placebo (CR 0,78; IC del 95%: 0,68 a 0,89), pero no en comparación con la AE (CR 0,97; IC del 95%: 0,75 a 1,26). EXPLICACIONES: Funded by drug company. There is evidence that industry-sponsored trials may overestimatethetreatmenteffect(Bhandari 2004). Los intervalos de confianza son amplios e incluyen no efecto. Estudio que evaluó intervención con Romiplostin.

Immunomodulatory Second-Line Therapies for Immune Thrombocytopenia.

Management of immune thrombocytopenia (ITP) is complex requiring communication between patients and caregivers to establish a mutual understanding of the impact of the patient's disease on quality of life, the current symptoms and risk of morbidity/mortality and the goals of therapy. The currently available second-line therapies for ITP provide potential for management of thrombocytopenia and bleeding symptoms with medical therapy or surgical intervention potentially offering long-term remission. All therapies are associated with potential side effects and necessary monitoring or modifications/risks and careful discussion of these is necessary to determine the optimal therapy for each patient. This review covers second-line therapies for ITP and discusses the currently available information on immunomodulatory second-line treatments for ITP.

Validation of the FACIT-fatigue subscale, selected items from FACT-thrombocytopenia, and the SF-36v2 in patients with chronic immune thrombocytopenia.

PURPOSE: To assess the validity and reliability of the fatigue subscale of the Functional Assessment of Chronic Illness Therapy (FACIT-F), a 6-item subset from the thrombocytopenia subscale of the Functional Assessment of Cancer Therapy (FACT-Th6) and the Short Form-36 Version 2 (SF-36v2) in 2 clinical trials of the thrombopoietin receptor agonist eltrombopag in chronic immune thrombocytopenia (ITP) patients. METHODS: In the 6-month, RAndomized placebo-controlled ITP Study with Eltrombopag (RAISE; n = 197), the FACIT-F, FACT-Th6, and SF-36v2 were administered at baseline, day 43, weeks 14 and 26, or early withdrawal. In the ongoing open-label extension study, Eltrombopag EXTENDed Dosing Study (EXTEND; n = 154), measures were administered at baseline, at the beginning of each stage, and at permanent discontinuation of study medication. RESULTS: FACIT-F, FACT-Th6, and SF-36v2 demonstrated acceptable internal consistency reliability (i.e., all Cronbach's alphas >0.70) and test-retest reliability (all intraclass correlation coefficients >0.70). Construct validity was supported by moderate (0.35 < r < 0.50) to strong (r > 0.50) inter-measure correlations for baseline and change scores. A small to medium magnitude of effect was captured by the FACIT-F and FACT-Th6 among patients who experienced sustained platelet responses. CONCLUSIONS: Results provide support for the validity, reliability, and responsiveness of the FACIT-F, FACT-Th6, and SF-36v2 in chronic ITP patients.

Chronic immune thrombocytopenic purpura. New agents.

First generation thrombopoietic growth factors (rhTPO and PEG-rHuMGDF), investigated in the early 2000s, proved effective in increasing platelet count in normal volunteers, in thrombocytopenia due to chemotherapy and also in a few cases of immune thrombocytopenic purpura (ITP). These agents did not complete their clinical development since one of them induced antibodies in the recipients that cross reacted with endogenous thrombopoietin (TPO), thus causing thrombocytopenia. This promoted the ingenious design of a new generation of thrombopoietic growth factors having no sequence homology with natural TPO. The two main agents are romiplostim, a peptibody already approved for clinical use in USA and eltrombopag, a non-peptide, orally active small molecule. In open label and placebo-controlled trials both agents proved to predictably increase platelet count in normal volunteers and in patients with ITP. With appropriate dosages (1-10 microg/kg weekly sub cutaneously for romiplostim; 50-75 mg/die per os for eltrombopag ) a platelet increase becomes significant after 7-10 days and peaks between 10-14 days. By discontinuing treatment, platelet count returns to baseline level in 10-15 days. The response rate with both agents is above 70-80%, also in patients that had undergone several lines of treatment, or that have failed splenectomy. The response is maintained during the treatment, but is almost invariably lost even after several months of successful administration. Due to the lack of a curative potential and to the incomplete knowledge of long-term side effects, the place of these new drugs in the management of ITP is still unsettled and their use is best restricted to refractory patients or in preparation of splenectomy. It seems however that a new paradigm in the treatment of ITP has been established where the focus is not on reducing platelet consumption but on increasing platelet production.

Review article: pharmacological approaches for the treatment of thrombocytopenia in patients with chronic liver disease and hepatitis C infection.

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.