Thrombopoietin Receptor Agonist Research Articles

Thrombopoietin mimetic reduces mouse lung inflammation and fibrosis after radiation by attenuating activated endothelial phenotypes.

Radiation-induced lung injury (RILI) initiates radiation pneumonitis and progresses to fibrosis as the main side effect experienced by patients with lung cancer treated with radiotherapy. There is no effective drug for RILI. Sustained vascular activation is a major contributor to the establishment of chronic disease. Here, using a whole thoracic irradiation (WTI) mouse model, we investigated the mechanisms and effectiveness of thrombopoietin mimetic (TPOm) for preventing RILI. We demonstrated that administering TPOm 24 hours before irradiation decreased histologic lung injury score, apoptosis, vascular permeability, expression of proinflammatory cytokines, and neutrophil infiltration in the lungs of mice 2 weeks after WTI. We described the expression of c-MPL, a TPO receptor, in mouse primary pulmonary microvascular endothelial cells, showing that TPOm reduced endothelial cell-neutrophil adhesion by inhibiting ICAM-1 expression. Seven months after WTI, TPOm-treated lung exhibited less collagen deposition and expression of MMP-9, TIMP-1, IL-6, TGF-β, and p21. Moreover, TPOm improved lung vascular structure, lung density, and respiration rate, leading to a prolonged survival time after WTI. Single-cell RNA sequencing analysis of lungs 2 weeks after WTI revealed that TPOm shifted populations of capillary endothelial cells toward a less activated and more homeostatic phenotype. Taken together, TPOm is protective for RILI by inhibiting endothelial cell activation.

Management of Adult Patients with Newly Diagnosed or Relapsed Primary Immune Thrombocytopenia in Eastern Austria.

Treatment sequence in primary immune thrombocytopenia (ITP) is based on national and international recommendations, treatment availability, and physician expertise. This article aimed to provide real-world data on treatment sequence and responses to first- and second-line treatments in newly diagnosed and relapsed adult ITP patients. We analyzed a cohort of 46 adult ITP patients from the Vienna ITP Biobank, who started first-line therapy within 1 week before their first study visit between February 2016 and March 2023. We investigated clinical patient characteristics and patient management in our specialized center and examined the impact of the international ASH guidelines on ITP treatment. Forty-six primary ITP patients, 27 (58.7%) with newly diagnosed ITP and 19 (41.3%) with relapsed ITP, were investigated. Most patients were female (65.2%) with a median platelet count of 9 × 109/L, and 31 patients (67.4%) had bleeding symptoms. All patients received first-line treatment with oral prednisolone; 15 patients received oral prednisolone combined with intravenous immunoglobulins (IVIGs), which were more commonly administered in newly diagnosed than in relapsed ITP patients. First-line therapy resulted an overall response in 82.6% of patients after a median (interquartile range [IQR]) time of 10 (5-25) days. There was no difference in treatment responses between newly diagnosed and relapsed ITP patients, but newly diagnosed patients had a shorter time to response (median [IQR]: 8 [5-14] and 14 [8-27], p = 0.02). Twenty-three (50%) of the patients (11/27 newly diagnosed [40.7%], 12/19 relapsed [63.2%]) required second-line ITP therapy. Thrombopoietin-receptor agonists (TPO-RAs) were the most commonly used second-line therapy with a response rate of 73.7%, and a median (IQR) time to treatment response of 15 (12-20) days. Overall response rates to TPO-RA treatment did not differ between newly diagnosed and relapsed ITP. Following the publication of novel guidelines in 2019, the median (IQR) duration of corticosteroid treatment shortened (100-52 days, p = 0.01), as did the time to second-line treatment (160-47 days, p = 0.01), and the median number of first-line therapies decreased from 2 (1-3) to 1 (1-2). Initial treatment with corticosteroids was effective in the majority of newly diagnosed and relapsed ITP. Response rates to initial corticosteroid treatment in ITP patients are consistent with previous data, but only 50% achieve sustained remission. TPO-RAs, which are well tolerated and effective, are the most commonly used second-line therapy in our study population. International guidelines have led to faster treatment transitions and reduced splenectomy rates. Integration of real-life experience, expert consensus, and guidelines optimizes ITP patient management.

Role of Azathioprine in the Management of ITP in the TPO-RA Era: A Single Centre Retrospective Study

Immune thrombocytopenia (ITP) is an autoimmune disease associated with low platelets and risk of bleeding. Standard-of-care treatment now includes the novel thrombopoietin-receptor agonists (TPO-RA). However, access to these modern therapeutics remains a challenge, limiting clinicians’ options. We investigated azathioprine in relapsed/refractory ITP to determine its efficacy and safety, focusing on evaluating its utility in post-TPO-RA patients.We retrospectively reviewed all adult patients, age 18 years and older, who were worked up for thrombocytopenia between 2009 and 2022 at a tertiary care centre in Ontario, Canada. Only ITP patients treated with azathioprine were included.We identified 92 ITP patients who received azathioprine, mean age 55.6 ± 22.3 years, 53 females and 39 males, with 64 having primary ITP. The overall response rate (ORR) was 47.8% (44/92), with a sustained response rate of 77.3% (34/44) at 6 months. Median time to response was 6 weeks. Fourteen patients (31.8%) relapsed with a median duration of response of 10 weeks. Most patients (73.9%) had documented side effects, with nausea/vomiting, infections and myelosuppression being the most common. The majority of patients received azathioprine as third-line; 6 patients were post-TPO-RA and 27 post-splenectomy. ORR was 50.0% (3/6) and 40.7% (11/27) in each group respectively.This is the largest retrospective study demonstrating benefit with azathioprine in relapsed/refractory ITP. Its efficacy remains consistent both post-TPO-RA (p=0.948) and post-splenectomy (p=0.259), offering clinicians a comparable drug response irrespective of prior TPO-RA exposure or splenectomy. We propose that azathioprine remains a viable option for relapsed/refractory ITP in the TPO-RA era.

A study of platelet function in patients with chronic immune thrombocytopenia treated with thrombopoietin receptor agonists

BackgroundThrombopoietin receptor agonists (TPO-RAs) are widely used in immune thrombocytopenia (ITP) and are associated with increased thrombotic risk. However, data regarding their impact on platelet function is scarce. MethodsPlatelet function was evaluated in chronic ITP patients enrolled over one year, using light transmission aggregometry and platelet-derived microparticle (PMP) levels measurement with flow cytometry. Aggregation responses to various concentrations of ADP, collagen, ristocetin, and PMP levels were compared between TPO-RA-treated patients, patients treated with other agents and healthy individuals. ResultsTPO-RA-treated patients (n = 24) displayed significantly reduced aggregation responses to 2.5 μM, 5 μM, and 10 μM of ADP and collagen compared to 15 healthy individuals (59.5 % vs. 87.6 %, p < .0001, 43.6 % vs. 79.9 %, p < .0001, 26.1 % vs. 75.2 %, p < .0001, 67.2 % vs. 86 %, p < .0001, respectively). Reduced responses to ADP and collagen were also recorded in patients treated with other agents (n = 16) compared to healthy controls but without difference between the two treatment groups. Aggregation response to ristocetin was normal in all three groups. None of the patients yielded enhanced platelet aggregation. In TPO-RA-treated patients, a strong positive correlation between platelet counts and aggregation response to ristocetin was observed (rs = 0.65, p = .0005). PMP levels were significantly elevated in TPO-RA-treated patients compared to patients treated with other agents (49.5 vs 4.5 events/uL, p < .0001) and healthy controls (5 events/uL, p < .0001). ConclusionsThese results suggest that TPO-RAs may not enhance platelet aggregation responses, whereas impaired responses may be a disease feature. Furthermore, TPO-RAs may increase PMP levels and thus be implicated in the modulation of platelet function in ITP patients.

Extension of impurity profiling on Eltrombopag olamine to in-silico Predictions: An Effort to Exploit correlated forced degradation products and known Drug-Related substances in drug discovery

The recent pandemic has highlighted the impact of diseases on global health and the economy. The rapid discovery of new hit molecules remains a tough challenge. Pharmaceutical impurity profiling can be linked to drug discovery through the identification of new hits from compounds identified during the analytical profiling. The present study demonstrates this linkage through the extension of the impurity (forced degradation) profiling of eltrombopag (ELT) olamine, a thrombopoietin (TPO) receptor agonist. The drug was exposed to standard degradation and the degradation products were primarily resolved and identified by UPLC-ESI-MS. This led to the identification of five forced degradation products (FDP). Thirty-three other known related substances (RS) of ELT, identified in the literature, were also considered. Molecular similarity checks were performed using Tanimoto similarity searches. A set of structurally and topologically similar molecules, including ELT and 15 RS, was established and subjected to in-silico toxicity-, absorption-, distribution-, metabolism-, and elimination (ADME) predictions. The RS, predicted with similar or lower toxicity than ELT and a comparable ADME profile, were subjected to molecular docking to trace changes in TPO receptor affinity. The results indicated that five RS had a high Jaccard’s similarity with ELT and higher or comparable docking scores. These compounds, along with few other impurities were predicted to have lower toxicity, better or comparable absorption, distribution, metabolism, and a better excretion profile than ELT. This justifies their entry as potential novel TPO receptor agonists in drug discovery.

Efficacy and Safety of Avatrombopag in Combination with Standard Immunosuppressive Therapy for Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a life-threatening bone marrow failure disease. The addition of eltrombopag to immunosuppressive therapy (IST) improves the response rate and response quality of SAAs, but its hepatotoxicity is concerning. Avatrombopag (AVA), another small-molecule thrombopoietin receptor agonist without hepatotoxicity, has unknown efficacy in SAA treatment. This retrospective study aimed to assess the efficacy and safety of AVA, a small-molecule thrombopoietin receptor agonist, when added to IST in SAA patients. A total of 42 patients treated with IST and AVA were compared to a historical cohort of 84 patients receiving IST alone, utilizing propensity score matching. The median age was 31.5 (6.0-67.0) years old in Group A and 26 (16.0-45.0) years old in Group B. At 3 months, Group A showed higher complete response (CR) and overall response (OR) rates than Group B (CR: 19.0% vs. 4.8%, P = 0.024; OR: 54.8% vs. 39.3%, P=0.145). Higher CR and OR rates were also found at 6 months in Group A than in Group B (CR 31.0% vs. 14.3%, P=0.145; OR 71.4% vs. 51.2%, P=0.048). In multivariate analysis of Group A, a shorter interval from disease onset to anti-thymocyte globulin (ATG) treatment (≤6 months) (P=0.005) predicted better responses rate at 6 months. Event free survival was also improved in Group A (60.7% vs. 49.6%). AVA was well-tolerated, with no hepatic injury observed during treatment, even in those with pre-existing hepatic impairment. The addition of AVA to IST improves both the response rate and response quality in SAA patients while ensuring safety.

Long term follow-up of the STOPAGO study

In an open prospective, multicenter study that enrolled 48 selected patients with chronic immune thrombocytopenia who achieved complete response for 1 year on thrombopoietin receptor agonists, half of the patients maintained a sustained response off treatment 4 years after treatment discontinuation. NCT03119974

Predictors for spontaneous remission in childhood chronic immune thrombocytopenia.

This study examined the factors associated with spontaneous remission in children with chronic immune thrombocytopenia (ITP). We retrospectively analyzed the medical records of patients diagnosed with ITP from January 1988 to December 2019 at our institute. A total of 104 children with chronic ITP were identified. The median follow-up time from diagnosis of chronic ITP was 3.6 years (IQR 1.2-8.3, range 0.1-31.4). Fifteen (14.4%) patients with severe symptoms received specific platelet-elevating therapies, including splenectomy, rituximab, and thrombopoietin receptor agonists. Seven of them achieved remission. Among the patients with a platelet count < 30 × 109/L at the time of diagnosis of chronic ITP, those who received specific platelet-elevating therapies had a higher remission rate compared to those who did not (HR: 4.66, 95% CI: 1.36-16.0). Sixteen patients (15.4%) developed systemic lupus erythematosus, 46 (44.2%) still had thrombocytopenia after a median follow-up of 6.8 years, and 42 (40.4%) achieved remission with a median time to remission of 2.0 years (IQR 0.6-4.1, range 0.1-15.7). The two independent predictive factors for spontaneous remission in childhood chronic ITP were platelet counts > 30 × 109/L at the time of diagnosis of chronic ITP (HR: 3.16, 95% CI: 1.51-6.62) and persistently negative ANA at follow-up (HR: 6.12, 95% CI: 1.46-25.7). The cumulative probabilities of spontaneous remission at 10 years post-diagnosis of chronic ITP were 72.2% for patients without risk factor compared to 0% for patients with two risk factors.

Avatrombopag for the treatment of patients with chemotherapy-induced thrombocytopenia: A case series.

Management of chemotherapy-induced thrombocytopenia (CIT) is challenging, often resulting in chemotherapy treatment delays, dose reduction, and treatment interruption. Randomized trials support the potential efficacy and safety of thrombopoietin receptor agonists in CIT management. A phase III trial of avatrombopag (AVA) demonstrated increased platelet counts (PC) in patients with solid tumours experiencing CIT. To complement those findings, this case series of six patients with solid tumours and CIT is presented. Results from these cases support the clinical benefit of AVA in improving PC and reducing the impact of CIT on tumour treatment, allowing continued therapy without dose reduction or treatment interruption.

Clinical research progress of lusutrombopag for the treatment of thrombocytopenia in chronic liver disease

Thrombocytopenia is one of the common complications with the hematologic system in patients with chronic liver disease, which often causes poor quality of life and high risk of bleeding, thereby affecting their diagnosis, treatment, and prognosis. Platelet transfusion can improve the patient's declining platelet count to a certain extent, but it has problems such as high price and being easy to cause immune rejection. Thrombopoietin (TPO), as an important cytokine that affects platelet production, can bind to TPO receptors and activate megakaryocytes to produce platelets. Lusutrombopag is a newly developed small-molecule TPO receptor agonist that can induce bone marrow progenitor cells to differentiate into megakaryocytes and increase platelet production, posing characteristics of oral convenience, safety and effectiveness; thus, it has been used in many countries and regions for the treatment of patients with chronic liver diseases concurrent with thrombocytopenia. Herein, the pharmacological features and clinical research are reviewed.

Thromboembolism adverse event profiles of thrombopoietin receptor agonists: a real-world, pharmacovigilance study

ABSTRACT Background Thrombopoietin receptor agonists (TPO-RAs) are currently approved for the treatment of thrombocytopenia in different conditions. The relationship between TPO-RAs and thromboembolic events (TEEs) remains controversial. Research design and methods We extracted TPO-RAs adverse reaction reports after their marketing until now, using the FDA adverse event reporting system (FAERS). Positive signals were detected by reporting odds ratios (RORs). And the Weibull shape parameter test was utilized to analyze the time-to-onset profiles. Result Thromboembolic events accounted for 8.97% among TPO-RAs reports. Increased reporting of TEEs was related to TPO-RAs treatment compared with the entire FAERS database [ROR = 2.65 (2.56, 2.73)]. In addition, venous thrombotic events [ROR = 4.13 (3.92, 4.35)] were reported more frequently than arterial events ROR = 1.81 (1.7, 1.93)]. Age over 60 years [odds ratio (OR) = 1.10 (1.01, 1.20), p = 0.029] and weight over 80 kg [OR = 1.36 (1.17, 1.58), p < 0.001] of patients might have higher risk of TEEs during TPO-RAs therapy. Conclusion Evidence from the real world suggested that TPO-RAs were associated with higher incidence of TEEs, particularly venous thrombosis. The risk of TPO-RAs-associated TEEs mostly happened in the early stages of treatment and decreased over time.

Durvalumab-Induced Immune Thrombocytopenia in Patients with Advanced Cholangiocarcinoma Undergoing Yttrium-90 Radioembolization

Introduction: Immune thrombocytopenia (ITP) secondary to durvalumab, a programmed cell death ligand 1 inhibitor, is a rare but clinically significant immune-related adverse event. Herein, we present 2 patients with cholangiocarcinoma who developed ITP immediately post-yttrium-90 radioembolization (Y90-RE) while on durvalumab-based systemic therapy. We hypothesize that given the timing, the immunotherapy and the radioembolization combination led to this event. It is not uncommon given the approval of immunotherapy and its role in locoregional therapies, that patients are treated with a combination of systemic immunotherapy and radioembolization or other forms of radiation, thus signifying the importance of potential complications. Case Presentation: Two patients, a 67-year-old female and a 60-year-old man, with biopsy-proven advanced unresectable cholangiocarcinoma, received a combination of systemic therapy with durvalumab, gemcitabine, and cisplatin and subsequently Y90-RE. Both patients developed ITP following in the immediate post-Y90-RE period. All other causes of ITP were comprehensively ruled out and treatment for ITP was initiated in the form of high-dose steroid and intravenous immunoglobulins. Durvalumab was discontinued, and only gemcitabine/cisplatin-based chemotherapy was continued thereafter. Due to recurrence, one of the patients required longer courses of steroids as well as thrombopoietin receptor agonists. Conclusion: Immunotherapy in the form of durvalumab and now pembrolizumab alongside chemotherapy is an approved first-line standard of care. Furthermore, it is not uncommon for patients to receive Y90-RE to improve patient outcomes. This report highlights the development of ITP in 2 patients who received durvalumab alongside Y90-RE. Awareness of this as a potential immune-mediated event is important to allow for close monitoring of platelet counts and for early intervention/management when this occurs.

The Establishment of a Novel Murine Model of Immune Thrombocytopenia in Pregnancy and the Impacts of Thrombopoietin Receptor Agonist on Platelet Production.

Objective Immune thrombocytopenia (ITP) is frequently associated with pregnancy. However, treatment options for ITP in pregnancy are limited, and there are few animal models available for the establishment of treatments. Here, we aimed to establish a novel murine pregnant model of ITP and to investigate the impacts of thrombopoietin receptor agonist (TPO-RA) on platelet production and reproductive outcomes. Methods Anti-glycoprotein Ib-alpha (GPIbα) antibody, which binds to megakaryocytes and platelets, was subcutaneously administered to pregnant mice in order to develop an ITP model (ITP group). TPO-RA was given in doses of 1 µg/kg, 10 µg/kg, and 100 µg/kg (low-dose group, mid-dose group, and high-dose group, respectively) for the treatment of ITP in pregnancy. Results The ITP group showed a significant reduction of platelet counts of less than 15% of healthy pregnant mice (control group) and also showed a significant increase in miscarriage rate (control group, 3.8%; ITP group, 44.4%; p < 0.05). Striking increases in platelet counts were observed in every TPO-RA group without any negative effects on fetal growth and placental pathology. No abnormality was noted in the external examination of fetal mice. Interestingly, a significant recovery of miscarriage rate was observed in the mid-dose group (23.5%) compared with the ITP group (p < 0.05). Conclusion A novel ITP model in pregnant mice was induced by injection of an anti-GPIbα antibody, and sufficient effects of TPO-RA on platelet production were observed in the present study. Furthermore, the positive impacts of TPO-RA on reproductive outcomes were revealed in the ITP model.

Avatrombopag in immune thrombocytopenia: A real-world study of the Spanish ITP Group (GEPTI).

Avatrombopag is the newest thrombopoietin receptor agonist (TPO-RA) approved to treat immune thrombocytopenia (ITP). Real-world evidence regarding effectiveness/safety is limited. The Spanish ITP Group (GEPTI) performed a retrospective study with patients starting avatrombopag for the first time. A total of 268 ITP patients were recruited. The median (interquartile range [IQR]) follow-up time was 47.5 (30.4-58.9) weeks. Among the 193 patients with baseline platelet counts <50 × 109/L, 174 (90.1%) of them achieved response (PC ≥50 × 109/L), and 113 (87.6%) of the 129 who persisted on avatrombopag at last visit had platelet levels above such threshold. Results were similar when only those patients switching to avatrombopag due to previous treatment failure were considered (n = 104). Patients reached response in 13 (7-21) days. Among patients with baseline levels ≥50 × 109/L, 73/75 (97.3%) reported response, which was maintained by 53 (94.6%) of the 56 who continued on avatrombopag at the end of the study. Loss-of-response was always <10%. ITP duration did not influence response. Approximately 79% (34/43) of heavily pretreated (≥4 lines) patients with baseline platelet counts <50 × 109/L switching after previous failure achieved PC ≥50 × 109/L. Previous use of eltrombopag and/or romiplostim did not influence response, regardless of whether previous TPO-RA(s) succeeded or failed. Avatrombopag allowed dose-reduction/suspension of corticosteroids in 40/50 (80.0%) patients with baseline platelet counts <50 × 109/L. Overall, 40/268 (14.9%) thrombocytosis and 12/268 (4.5%) thromboembolic events were reported. Our real-world cohort supports the use of avatrombopag to manage ITP, regardless of disease severity and treatment history.

Real-world evidence of avatrombopag for the treatment of immune thrombocytopenia intolerant or ineffective to eltrombopag/hetrombopag.

Due to the limited real-world research on the application of avatrombopag (AVA) for immune thrombocytopenia (ITP) in China, we evaluated the effectiveness and safety of AVA in clinical practice. We included 121 adult ITP patients treated with AVA across three medical centres. Based on the reasons for choosing AVA, these patients were divided into eltrombopag (ELT)/hetrombopag (HET) intolerance group (IG), and ELT/HET unresponsive group (UG). Compared with UG, more patients in IG had a history of liver disease and received fewer treatments before AVA. Amongst all patients, 83% had platelet response (≥30 × 109/L) after AVA and 62% achieved complete response (≥100 × 109/L, CR). Sixty-two percent in IG and 56% in UG were able to discontinue more than one concomitant ITP medication. A total of 17 patients underwent multiple switches of thrombopoietin receptor agonists (TPO-RAs), resulting in an 88% platelet response rate. Sixty-three patients discontinued AVA, 27% were due to unaffordability. AVA was well tolerated in most patients. In the ITP population, AVA proved effective and safe, particularly in patients intolerant or unresponsive to ELT/HET. Patients benefited from TPO-RAs switches, particularly those undergoing multiple switches. However, many patients struggled with the long-term financial burden of AVA.

Efficacy and safety of TPO receptor agonists in treatment of ITP associated with predominantly antibody deficiencies

AbstractPredominantly antibody deficiencies have an estimated prevalence of >1 in 25 000. Their classical phenotype entails the association of autoimmune manifestations with increased susceptibility to infections. Up to 8% of these patients ultimately develop immune thrombocytopenic purpura (ITP). Reducing the risk for infections and considering nonimmunosuppressive treatments, such as thrombopoietin receptor agonists (TPO-RAs), are important considerations for these patients. This nationwide retrospective case series assessed the outcomes and safety of TPO-RAs as treatment for ITP in adults diagnosed with predominantly antibody deficiencies. Response and complete response to treatment were defined as platelet count reaching 30 × 109/L and 100 × 109/L, respectively. We analyzed data from 28 patients. The median follow-up time after introduction of the first TPO-RAs was 33 months (range, 2 weeks to 10.6 years). After 6 weeks of follow-up, response was achieved in 24 of the 28 patients (85.7%), and among those, 21 patients (75%) displayed a complete response. At the last available follow-up visit, only 7 patients (25%) needed second-line therapies for ITP, and among those, only 5 patients (17.9%) received immunosuppressants. Only 3 patients (10.7%) reported laboratory-confirmed hepatobiliary adverse events of light or mild severity and 3 patients (10.7%) reported thrombotic events. In conclusion, TPO-RAs seemed to be an effective and safe option of treatment in these case series. Our results suggest that eltrombopag or romiplostim should be considered as second-line therapy for ITP related to predominantly antibody deficiencies.

Tapering and Sustained Remission of Thrombopoietin Receptor Agonists (TPO-RAs): Is it Time for Paediatric ITP?

Thrombopoietin receptor agonists (TPO-Ras; romiplostim/eltrombopag/avatrombopag) have demonstrated high efficacy rates (59-88%) and a good safety profile in clinical trials with adult patients with immune thrombocytopenia (ITP). Similar efficacy and safety results have been observed with romiplostim and eltrombopag in paediatric cohorts. Continuous treatment with TPO-RAs has shown durable responses with long-term use, up to 3years. The effect of TPO-RAs was generally considered transient, as platelet counts tended to drop to baseline values after a short period of time (about 2weeks), unless treatment was maintained. Several groups have reported successful discontinuation of TPO-RAs without the need for concomitant treatments. This is referred to as sustained remission off treatment (SROT). Both short- and medium-term treatment with TPO-RAs may reduce costs to our healthcare systems and, more importantly, may reduce the potential side effects that may be associated with continuous TPO-RA treatment. The issue of tapering and discontinuation of TPO-RAs in paediatric patients with ITP has received little attention to date. Given that paediatric ITP has much higher rates of spontaneous remission than ITP in adults, we consider that the possibility of SROT of TPO-RAs in paediatric patients with ITP is a neglected but very relevant issue in this subtype of the disease.

Research Advances in the Treatment of Eltrombopag for Adult Patients with Primary Immune Thrombocytopenia--Review

Primary immune thrombocytopenia (ITP) is an autoimmune disease characterized by thrombocytopenia, and T cell immune dysfunction plays an important role in the formation of ITP. As a thrombopoietin receptor agonist (TPO- RA), eltrombopag can not only directly stimulate megakaryocytes to produce platelets, but also play an immunomodulatory role by inducing regulatory T cell generation and reducing proinflammatory factors. As a second-line treatment drug for adult ITP, eltrombopag is increasingly widely used in clinical practice. This review summarized the latest research progress on the mechanism of action, efficacy, safety, and how to reduce the dosage of eltrombopag in ITP.

Efficacy and safety of hetrombopag in the treatment of recombinant human thrombopoietin–resistant thrombocytopenia after allogeneic hematopoietic stem cell transplantation

BackgroundThrombocytopenia after allogeneic hematopoietic cell transplantation is a challenging clinical problem. Recombinant human thrombopoietin (rhTPO) and thrombopoietin receptor agonists are increasingly used in posttransplant thrombocytopenia. However, the use of hetrombopag in patients with posttransplant thrombocytopenia, especially in patients with resistance to rhTPO, has not yet been reported. ObjectivesThe present study aimed to investigate the efficacy and safety of hetrombopag in patients with rhTPO-resistant posttransplant thrombocytopenia. MethodsThis retrospective study included 21 patients with rhTPO-resistant posttransplant thrombocytopenia who received hetrombopag from August 2021 to July 2022. The primary endpoint was the overall response rate, including partial response and complete response (CR). We also evaluated the predictors of hetrombopag efficacy and adverse events. ResultsThe overall response rate to hetrombopag was 81%, and the CR rate was 62%. The median time from hetrombopag initiation to response and CR were 16 and 31 days, respectively. Decreased megakaryocytes in bone marrow negatively correlated with CR to hetrombopag (P = .027). All the patients tolerated hetrombopag well without any significant increase in adverse events. At the last follow-up, 71% of responders had discontinued hetrombopag and sustained their best response. ConclusionOur results suggested that hetrombopag is an effective treatment option to promote platelet recovery in patients with posttransplant thrombocytopenia, even in patients resistant to rhTPO.

What is the best second-line treatment for immune thrombocytopenia?

The choice between thrombopoietin receptor agonists (TPO-RAs) and anti-CD20 as the preferred second-line therapies for immune thrombocytopenia remains in the eye of the beholders. Each has major advantages and certain weaknesses. Stolz etal. describe a single-centre experience that whets our appetite for a large randomized controlled trial comparing a TPO agonist and an anti-CD20 agent. Commentary on: Stolz etal. Efficacy of thrombopoietin receptor agonists versus rituximab in non-responsive immune thrombocytopenia - A single center retrospective analysis. Br J Haematol 2024; 205:1121-1125.