Romiplostim in chemotherapy-induced thrombocytopenia: A review of the literature.

Chemotherapy-induced thrombocytopenia (CIT) is a common challenge of cancer therapy and can lead to chemotherapy dose reduction, delay, and/or discontinuation, affecting relative dose intensity, and possibly adversely impacting cancer care. Besides changing anticancer regimens, standard management of CIT has been limited to platelet transfusions and supportive care. Use of the thrombopoietin receptor agonist romiplostim, already approved for use in immune thrombocytopenia, has shown promising signs of efficacy in CIT. In a phase 2 prospective randomized study of solid tumor patients with platelet counts <100 × 109/L for ≥4 weeks due to CIT, weekly romiplostim corrected the platelet count to >100 × 109/L in 93% (14/15) of patients within 3 weeks versus 12.5% (1/8) of untreated patients (p < 0.001). Including patients treated with romiplostim in an additional single-arm cohort, 85% (44/52) of all romiplostim-treated patients responded with platelet count correction within 3 weeks. Several retrospective studies of CIT have also shown responses to weekly romiplostim, with the largest study finding that poor response to romiplostim was predicted by tumor invasion of the bone marrow (odds ratio, 0.029; 95% CI: 0.0046-0.18; p < 0.001), prior pelvic irradiation (odds ratio, 0.078; 95% CI: 0.0062-0.98; p = 0.048), and prior temozolomide treatment (odds ratio 0.24; 95% CI: 0.061-0.96; p = 0.043). Elsewhere, lower baseline TPO levels were predictive of romiplostim response (p = 0.036). No new safety signals have emerged from romiplostim CIT studies. Recent treatment guidelines, including those from the National Comprehensive Cancer Network, now support consideration of romiplostim use in CIT. Data are expected from two ongoing phase 3 romiplostim CIT trials.

Thrombopoietin improves the functions of bone marrow endothelial progenitor cells via METTL16/Akt signalling of haematological patients with chemotherapy-induced thrombocytopenia.

Bone marrow endothelial progenitor cells (BM EPCs) are crucial in supporting haematopoietic regeneration, while the BM EPCs of haematological patients with chemotherapy-induced thrombocytopenia (CIT) are unavoidably damaged. Therefore, the present study aimed to examine the effect of thrombopoietin (TPO) on the recovery of BM EPCs of CIT patients and to identify the underlying mechanisms. The cell functions were determined by 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil)-acetylated low-density lipoprotein (Dil-Ac-LDL) uptake and fluorescein isothiocyanate (FITC)-labeled Ulex europaeus agglutinin-I (FITC-UEA-I) binding assay, as well as proliferation, migration and tube formation experiments. Endothelial cells were transfected with METTL16 lentivirus, followed by methylated RNA immunoprecipitation sequencing. Zebrafish with vascular defect was used as the in vivo model. TPO significantly improved the quantity and functions of BM EPCs from CIT patients in vitro and restored the subintestinal vein area of zebrafish with vascular defect in vivo. Mechanically, TPO enhanced the BM EPC functions through Akt signal mediated by METTL16, which was downregulated in BM EPCs of CIT patients and involved in the regulation of endothelial functions. The present study demonstrates that TPO improves the recovery of BM EPCs from CIT patients with haematological malignancies via METTL16/Akt signalling, which provides new insights into the role of TPO in treating CIT in addition to direct megakaryopoiesis.

Avatrombopag for severe refractory thrombocytopenia in a pediatric patient with ALL following allogeneic hematopoietic stem cell transplantation: A case report.

Patients who receive allogeneic hematopoietic stem cell transplantation (alloHSCT) are at risk for developing persistent thrombocytopenia. Here, we describe treatment with avatrombopag, a thrombopoietin receptor agonist, in a pediatric patient with chronic, severe, transfusion-dependent thrombocytopenia (<10 × 103/µL) post-alloHSCT that was persistent despite treatment with romiplostim, another thrombopoietin receptor agonist. Following the granting of a compassionate use investigational new drug authorization, avatrombopag treatment was initiated, and the patient's platelet count increased. To date, the patient has maintained a platelet count >100 × 103/µL. No adverse events or medication toxicities have been reported, and he has resumed his pre-alloHSCT activities.

Immune thrombocytopenia and pregnancy: challenges and opportunities in diagnosis and management.

INTRODUCTION: Immune thrombocytopenia (ITP) affecting pregnancy is a diagnostic and often a therapeutic challenge. AREAS COVERED: We review the current diagnostic criteria for ITP in pregnancy and the potential utility of laboratory tests. We discuss the impact of ITP on pregnancy outcomes and the effects of pregnancy on patients living with chronic ITP.  We describe the criteria for intervention, the evidence supporting first-line treatment approaches and the therapeutic decisions and challenges in cases refractory to steroids and IVIG. We review the evidence supporting the potential use of thrombopoietin receptor agonists for refractory thrombocytopenia. Finally, we describe the diagnostic, prognostic, and treatment approaches to neonatal ITP and considerations regarding breastfeeding. We searched the terms 'immune thrombocytopenia' and 'pregnancy' on PubMed to identify the relevant literature published before 31 December 2023, including within cited references. EXPERT OPINION: Decreased platelet production may play a role in pregnancy-related ITP exacerbation. Putative mechanisms include placental hormones, such as inhibin. Although IVIG and prednisone usually suffice to achieve hemostasis for delivery, second-line agents are sometimes required to allow for neuraxial anesthesia. There is growing evidence supporting the use of romiplostim during pregnancy; however, its risk of venous thromboembolism warrants further evaluation.

Romiplostim for treatment of thrombocytopenia in dogs: A retrospective assessment and clinical outcomes.

BACKGROUND: Romiplostim, a thrombopoietin analog, is commonly used to treat immune-mediated thrombocytopenia (ITP) in humans, but its use in dogs remains limited. OBJECTIVES: Evaluate the effects and adverse events of romiplostim administration in dogs with thrombocytopenia caused by various underlying diseases. ANIMALS: Forty-two client-owned dogs with naturally occurring thrombocytopenia at 2 referral animal hospitals. METHODS: Retrospective, multi-institutional analysis to evaluate the outcomes of romiplostim treatment in dogs. RESULTS: Among the dogs treated with romiplostim, 27 experienced an increase in platelet count and 26 maintained a platelet count within the reference range. Platelet count improvement was observed in various conditions: primary ITP (90%, n = 18/20), pancytopenia of unknown etiology (42.9%, n = 3/7), chemotherapy-induced thrombocytopenia (50%, n = 3/6), babesiosis (100%, n = 1/1), radiotherapy-induced thrombocytopenia (0%, n = 0/1), and disseminated intravascular coagulopathy (33.3%, n = 2/6). The median time for platelet recovery (>50 000/µL) after romiplostim administration was 4 days, and the median time for platelet count normalization was 7 days. Median hospitalization time for the improvement group (I) was 5 days. The survival-to-discharge rates were 85%, 40%, and 28.6% for dogs with primary ITP, secondary thrombocytopenia, and thrombocytopenia of unknown etiology, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Romiplostim is a well-tolerated and promising treatment for primary ITP in dogs, suggesting its potential as a valuable therapeutic option for dogs with thrombocytopenia caused by various underlying conditions. These findings emphasize the need for further research to optimize romiplostim dosing and understand its role in treating secondary thrombocytopenia and pancytopenia of unknown etiology.

Transition of signal requirement in hematopoietic stem cell development from hemogenic endothelial cells.

Hematopoietic stem cells (HSCs) develop from hemogenic endothelial cells (HECs) in vivo during mouse embryogenesis. When cultured in vitro, cells from the embryo phenotypically defined as pre-HSC-I and pre-HSC-II have the potential to differentiate into HSCs. However, minimal factors required for HSC induction from HECs have not yet been determined. In this study, we demonstrated that stem cell factor (SCF) and thrombopoietin (TPO) induced engrafting HSCs from embryonic day (E) 11.5 pre-HSC-I in a serum-free and feeder-free culture condition. In contrast, E10.5 pre-HSC-I and HECs required an endothelial cell layer in addition to SCF and TPO to differentiate into HSCs. A single-cell RNA sequencing analysis of E10.5 to 11.5 dorsal aortae with surrounding tissues and fetal livers detected TPO expression confined in hepatoblasts, while SCF was expressed in various tissues, including endothelial cells and hepatoblasts. Our results suggest a transition of signal requirement during HSC development from HECs. The differentiation of E10.5 HECs to E11.5 pre-HSC-I in the aorta-gonad-mesonephros region depends on SCF and endothelial cell-derived factors. Subsequently, SCF and TPO drive the differentiation of E11.5 pre-HSC-I to pre-HSC-II/HSCs in the fetal liver. The culture system established in this study provides a beneficial tool for exploring the molecular mechanisms underlying the development of HSCs from HECs.

Romiplostim use in immune thrombocytopenia: Experience in Cuenca, Ecuador / Uso de romiplostim en trombocitopenia inmunitaria: experiencia en Cuenca (Ecuador)

Introduction. The international consensus and the American Society of Hematology guidelines from 2019 established thrombopoietin analogues as the second-line therapy for primary immune thrombocytopenia cases. Objectives. To describe romiplostim usefulness in patients with immune thrombocytopenia in a third-level hospital in Cuenca, Ecuador. Materials and methods. We conducted a descriptive and retrospective study in patients with immune thrombocytopenia treated with romiplostim. We evaluated the following variables: age, gender, previous therapies to romiplostim, dose, frequency, complications, change of thrombopoietin analogue, and treatment discontinuation. Results. We included 21 patients with immune thrombocytopenia treated with romiplostim, with a median age of 49 years. All patients received corticosteroids as first-line treatment. Three patients required longer administration intervals (over a week), with weekly doses lower than those recommended (< 1 µg/kg). Due to lack of efficacy, six patients replaced elthrombopag with romiplostim. Of the total, three suffered thrombotic complications: two had portal venous thrombosis, and one had pulmonary thromboembolism; five of the patients discontinued romiplostim scheme without resuming it. Conclusions. Romiplostim constitutes a convenient second-line therapy in immune thrombocytopenia. Despite the small sample size, romiplostim early use can minimize toxicities and infectious risks.

Introducción: El consenso internacional y la guía del 2019 de la American Society of Hematology, establecieron a los análogos de la trombopoyetina como medicamentos de segunda línea para tratar la trombocitopenia inmunitaria primaria. En Ecuador, se comercializan dos trombomiméticos: romiplostim y eltrombopag OBJETIVOS: Describir el uso de romiplostim en pacientes con trombocitopenia inmunitaria, en un hospital de tercer nivel en Cuenca (Ecuador). Materiales y métodos. Se adelantó un estudio descriptivo y retrospectivo en pacientes con trombocitopenia inmunitaria y tratamiento con romiplostim. Se evaluaron las siguientes variables: edad, sexo, tratamientos previos a romiplostim, dosis, frecuencia, complicaciones, cambio de análogo de trombopoyetina y discontinuación de la terapia. RESULTADOS: Veintiún pacientes con trombocitopenia inmunitaria fueron tratados con romiplostim, con una mediana de 49 años. Todos recibieron corticoides como tratamiento de primera línea. Tres precisaron de intervalos más prolongados que el semanal, con dosis semanales menores de las recomendadas (< 1 µg/kg). Por falta de eficacia, en seis pacientes se reemplazó la terapia con eltrombopag por romiplostim. Tres pacientes padecieron complicaciones trombóticas: dos, trombosis venosa portal, y uno, tromboembolia pulmonar. En cinco, se discontinuó el tratamiento con romiplostim, sin necesidad de reanudarlo. CONCLUSIONES: Romiplostim constituye un tratamiento de segunda línea para la trombocitopenia inmunitaria primaria. A pesar del reducido tamaño de la muestra, se observó que la administración temprana del medicamento puede minimizar toxicidades y riesgos infecciosos.

Recombinant human thrombopoietin in alleviating endothelial cell injury in sepsis.

Background: To evaluate the effect of recombinant human thrombopoietin (rhTPO) on clinical prognosis by exploring changes in endothelial cell injury markers and inflammatory factors in patients with sepsis after treatment with rhTPO. Methods: This retrospective observational study involved patients with sepsis (diagnosed according to Sepsis 3.0) admitted to Shanghai General Hospital intensive care unit from January 1, 2019 to December 31, 2022. Patients were divided into two groups (control and rhTPO) according to whether they received rhTPO. Baseline information, clinical data, prognosis, and survival status of the patients, as well as inflammatory factors and immune function indicators were collected. The main monitoring indicators were endothelial cell-specific molecule (ESM-1), human heparin-binding protein (HBP), and CD31; secondary monitoring indicators were interleukin (IL)-6, tumor necrosis factor (TNF)-α, extravascular lung water index, platelet, antithrombin III, fibrinogen, and international normalized ratio. We used intraperitoneal injection of lipopolysaccharide (LPS) to establish a mouse model of sepsis. Mice were randomly divided into four groups: normal saline, LPS, LPS + rhTPO, and LPS + rhTPO + LY294002. Plasma indicators in mice were measured by enzyme-linked immunosorbent assay. Results: A total of 84 patients were included in the study. After 7 days of treatment, ESM-1 decreased more significantly in the rhTPO group than in the control group compared with day 1 (median=38.6 [interquartile range, IQR: 7.2 to 67.8] pg/mL vs. median=23.0 [IQR: -15.7 to 51.5] pg/mL, P=0.008). HBP and CD31 also decreased significantly in the rhTPO group compared with the control group (median=59.6 [IQR: -1.9 to 91.9] pg/mL vs. median=2.4 [IQR: -23.2 to 43.2] pg/mL; median=2.4 [IQR: 0.4 to 3.5] pg/mL vs. median=-0.6 [IQR: -2.2 to 0.8] pg/mL, P <0.001). Inflammatory markers IL-6 and TNF-α decreased more significantly in the rhTPO group than in the control group compared with day 1 (median=46.0 [IQR: 15.8 to 99.1] pg/mL vs. median=31.2 [IQR: 19.7 to 171.0] pg/mL, P <0.001; median=17.2 [IQR: 6.4 to 23.2] pg/mL vs. median=0.0 [IQR: 0.0 to 13.8] pg/mL, P=0.010). LPS + rhTPO-treated mice showed significantly lower vascular von Willebrand factor (P=0.003), vascular endothelial growth factor (P=0.002), IL-6 (P <0.001), and TNF-α (P <0.001) than mice in the LPS group. Endothelial cell damage factors vascular von Willebrand factor (P=0.012), vascular endothelial growth factor (P=0.001), IL-6 (P <0.001), and TNF-α (P=0.001) were significantly elevated by inhibiting the PI3K/Akt pathway. Conclusion: rhTPO alleviates endothelial injury and inflammatory indices in sepsis, and may regulate septic endothelial cell injury through the PI3K/Akt pathway.

[Current trends in the treatment of aplastic anemia].

Aplastic anemia is a syndrome characterized by reduced hematopoietic stem cells, bone marrow hypoplasia, and pancytopenia, and is often considered a T-cell-mediated autoimmune disease. It is predominantly treated with hematopoietic stem cell transplantation and immunosuppressive therapy with anti-human thymocyte immunoglobulin (ATG) and cyclosporine. Only rabbit ATG was previously available in Japan, but equine ATG was recently approved for use in 2023. Thrombopoietin receptor agonists available in Japan are oral eltrombopag and injectable romiplostim. In hematopoietic stem cell transplantation for aplastic anemia, a conditioning regimen of reduced-dose cyclophosphamide and fludarabine has been used to reduce cardiotoxicity. Human leukocyte antigen haploidentical stem cell transplants have also been developed, and their use in patients without a donor is increasingly reported. Future advancements in novel drugs and transplantation therapies could revolutionize the management of aplastic anemia.

Treatment of Immune Thrombocytopenia: Contextualization from a Historical Perspective.

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by an isolated decrease in platelet count and an increased risk of bleeding. The pathogenesis is complex, affecting multiple components of the immune system and causing both peripheral destruction of platelets and inadequate production in the bone marrow. In this article, we review the treatment of ITP from a historical perspective, discussing first line and second line treatments, and management of refractory disease.

Real-world experience of thrombopoietin receptor agonists in pediatric immune thrombocytopenia: a report from a Chinese tertiary children's hospital.

Background: Primary immune thrombocytopenia (ITP) is the most common bleeding disorder in children. There are approximately 20% pediatric ITP patients respond poor to corticosteroids as first-line treatment. Recently thrombopoietin receptor agonists (TPO-RAs) have been used to treat refractory ITP and have achieved certain therapeutic effects. To investigate the efficacy and safety of TPO-RAs in the treatment of pediatric ITP, we conducted this real-world study. Methods: Fifty-three pediatric patients with ITP who did not respond well to corticosteroids were treated with TPO-RAs. Clinical data, including therapeutic response rate, changes in platelet (PLT) count, and adverse events (AEs) were collected. Results: Of the 51 evaluable patients, 37 (72.5%) responded to TPO-RAs. Patients aged >4 years had a higher response rate than those aged ≤4 years (81.1% vs. 50.0%, P=0.04). There was no effect of sex, duration of disease, prior therapy, Mycoplasma pneumoniae (MP) immunoglobulin M (IgM) positivity, antinuclear antibody (ANA) positivity, CD4/CD8 ratio or baseline PLT count on the response rate (P>0.05). Other than 10 patients with PLT counts that exceeded the upper limit of normal, AEs were sporadic, including increased aminotransferase levels, cough, headache, and vomiting. Conclusions: TPO-RAs exhibited good clinical efficacy in pediatric ITP patients who failed to respond to first-line treatment, especially patients aged >4 years, and the side effects were minor.

Recombinant human thrombopoietin improves platelet engraftment after autologous hematopoietic stem cell transplantation in patients with aggressive lymphoma.

BACKGROUND: To explore the efficiency and safety of recombinant human thrombopoietin (TPO) on the platelet engraftment after autologous stem cell transplantation (ASCT) in patients with aggressive lymphoma. PATIENTS AND METHODS: Forty patients were enrolled in a single-center, retrospective clinical trial from July 2019 with rhTPO administration when the platelet count ≤ 75 × 109/L after the reinfusion of stem cells. The hematopoietic reconstitution, platelet transfusion dependence, the cost and length of hospitalization, side effects and survival benefit were compared between the rhTPO group and the control group of 25 historic patients without rhTPO. RESULTS: The cumulative incidence of platelet engraftment in the rhTPO group was significantly higher since d+ 13 post-transplantation. But no difference of neutrophil engraftment was found. rhTPO was considered to influence the platelet engraftment independently by multivariate analysis. Subgroup analysis demonstrated that when the patients were older than 45 years old, male, at stage-IV as diagnosed and obtained PR after previous treatment, rhTPO was more recommended to facilitate platelet early engraftment after ASCT. Although rhTPO didn't relieve the dependency of platelet transfusion, patients had the shorter length of hospitalization. And better OS was shown in the rhTPO group. CONCLUSION: rhTPO improved platelet engraftment after ASCT with aggressive lymphoma, especially the ones older than 45 years old, male, at stage-IV as diagnosed and obtained PR after previous treatment. Although rhTPO didn't lessen platelet transfusion dependence, the length and medical cost of hospitalization were reduced when rhTPO was involved. rhTPO was efficacy and safety which could be recommended after ASCT.

Final Results from the First European Real-World Experience on Lusutrombopag Treatment in Cirrhotic Patients with Severe Thrombocytopenia: Insights from the REAl-World Lusutrombopag Treatment in ITalY Study.

Background and aims: Management of severe thrombocytopenia poses significant challenges in patients with chronic liver disease. Here, we aimed to evaluate the first real-world European post-marketing cohort of cirrhotic patients treated with lusutrombopag, a thrombopoietin receptor agonist, verifying the efficacy and safety of the drug. Methods: In the REAl-world Lusutrombopag treatment in ITalY (REALITY) study, we collected data from consecutive cirrhotic patients treated with lusutrombopag in 19 Italian hepatology centers, mostly joined to the "Club Epatologi Ospedalieri" (CLEO). Primary and secondary efficacy endpoints were the ability of lusutrombopag to avoid platelet transfusions and to raise the platelet count to ≥50,000/µL, respectively. Treatment-associated adverse events were also collected. Results: A total of 66 patients and 73 cycles of treatment were included in the study, since 5 patients received multiple doses of lusutrombopag over time for different invasive procedures. Fourteen patients (19%) had a history of portal vein thrombosis (PVT). Lusutrombopag determined a significant increase in platelet count [from 37,000 (33,000-44,000/µL) to 58,000 (49,000-82,000), p < 0.001]. The primary endpoint was met in 84% of patients and the secondary endpoint in 74% of patients. Baseline platelet count was the only independent factor associated with response in multivariate logistic regression analysis (OR for any 1000 uL of 1.13, CI95% 1.04-1.26, p 0.01), with a good discrimination power (AUROC: 0.78). Notably, a baseline platelet count ≤ 29,000/µL was identified as the threshold for identifying patients unlikely to respond to the drug (sensitivity of 91%). Finally, de novo PVT was observed in four patients (5%), none of whom had undergone repeated treatment, and no other safety or hemorrhagic events were recorded in the entire population analyzed. Conclusions: In this first European real-world series, lusutrombopag demonstrated efficacy and safety consistent with the results of registrational studies. According to our results, patients with baseline platelet counts ≤29,000/µL are unlikely to respond to the drug.

Hetrombopag for the management of chemotherapy-induced thrombocytopenia in patients with advanced solid tumors: a multicenter, randomized, double-blind, placebo-controlled, phase II study.

Background: Chemotherapy-induced thrombocytopenia (CIT) increases the risk of bleeding, necessitates chemotherapy dose reductions and delays, and negatively impacts prognosis. Objectives: This study aimed to evaluate the efficacy and safety of hetrombopag for the management of CIT in patients with advanced solid tumors. Design: A multicenter, randomized, double-blind, placebo-controlled, phase II study. Methods: Patients with advanced solid tumors who experienced a chemotherapy delay of ⩾7 days due to thrombocytopenia (platelet count <75 × 109/L) were randomly assigned (1:1) to receive oral hetrombopag at an initial dose of 7.5 mg once daily or a matching placebo. The primary endpoint was the proportion of treatment responders, defined as patients resuming chemotherapy within 14 days (platelet count ⩾100 × 109/L) and not requiring a chemotherapy dose reduction of ⩾15% or a delay of ⩾4 days or rescue therapy for two consecutive cycles. Results: Between 9 October 2021 and 5 May 2022, 60 patients were randomized, with 59 receiving ⩾1 dose of assigned treatment (hetrombopag/placebo arm, n = 28/31). The proportion of treatment responders was significantly higher in the hetrombopag arm than in the placebo arm [60.7% (17/28) versus 12.9% (4/31); difference of proportion: 47.6% (95% confidence interval (CI): 26.0-69.3); odds ratio = 10.44 (95% CI: 2.82-38.65); p value (nominal) based on the Cochran-Mantel-Haenszel: <0.001)]. During the double-blind treatment period, grade 3 or higher adverse events (AEs) occurred in 35.7% (10/28) of patients with hetrombopag and 38.7% (12/31) of patients on placebo. The most common grade 3 or higher AEs were decreased neutrophil count [35.7% (10/28) versus 35.5% (11/31)] and decreased white blood cell count [17.9% (5/28) versus 19.4% (6/31)]. Serious AEs were reported in 3.6% (1/28) of patients with hetrombopag and 9.7% (3/31) of patients with placebo. Conclusion: Hetrombopag is an effective and well-tolerated alternative for managing CIT in patients with solid tumors. Trial registration: ClinicalTrials.gov identifier: NCT03976882.

Thrombopoietin receptor agonists regulate myeloid-derived suppressor cell-mediated immunomodulatory effects in ITP.

TPO receptor agonists (TPO-RAs) are a class of clinical second-line regimens for the treatment of primary immune thrombocytopenia (ITP). It can promote megakaryocyte maturation and increase platelet production, but its effect on immunosuppressive cells in patients with ITP has not been explored. Sixty-two ITP patients and 34 healthy controls (HCs) were included in this study. The proportion and functions of myeloid-derived immunosuppressive cells (MDSCs) in ITP patients and HCs were investigated. We found that the proportion and function of MDSCs in ITP patients treated with TPO-RAs were significantly higher than those treated with glucocorticoids (GCs), which was correlated with the clinical efficacy. The proportion and function of cytotoxic Th1 cells and CD8+T cells decreased, while the proportion and immunosuppressive function of Treg cells increased in ITP patients treated with TPO-RAs. We further proved, through MDSC depletion tests, that the inhibitory effect of MDSCs on Th1 cells and the promotion of Treg cells in the original immune micro-environment of GCs-treated ITP patients were impaired; however, these MDSCs' functions were improved in TPO-RAs-treated patients. Finally, we found that the KLF9 gene in MDSCs cells of ITP patients treated with TPO-RAs was down-regulated, which contribute to the higher mRNA expression of GADD34 gene and improved function of MDSCs. These results demonstrate a novel mechanism of TPO-RAs for the treatment of ITP through the assessment of MDSCs and their subsequent impact on T cells, which provides a new basis for TPO-RAs as first-line treatment approach to the treatment of ITP.

Switching from eltrombopag to hetrombopag in patients with primary immune thrombocytopenia: a post-hoc analysis of a multicenter, randomized phase III trial.

While studies have explored the feasibility of switching between various thrombopoietin receptor agonists in treating immune thrombocytopenia (ITP), data on the switching from eltrombopag to hetrombopag remains scarce. This post-hoc analysis of a phase III hetrombopag trial aimed to assess the outcomes of ITP patients who switched from eltrombopag to hetrombopag. In the original phase III trial, patients initially randomized to the placebo group were switched to eltrombopag. Those who completed this 14-week eltrombopag were eligible to switch to a 24-week hetrombopag. Treatment response, defined as a platelet count of ≥ 50 × 109/L, and safety were evaluated before and after the switch. Sixty-three patients who completed the 14-week eltrombopag and switched to hetrombopag were included in this post-hoc analysis. Response rates before and after the switch were 66.7% and 88.9%, respectively. Among those with pre-switching platelet counts below 30 × 109/L, eight out of 12 patients (66.7%) responded, while eight out of nine patients (88.9%) with pre-switching platelet counts between 30 × 109/L and 50 × 109/L responded post-switching. Treatment-related adverse events were observed in 50.8% of patients during eltrombopag treatment and 38.1% during hetrombopag treatment. No severe adverse events were noted during hetrombopag treatment. Switching from eltrombopag to hetrombopag in ITP management appears to be effective and well-tolerated. Notably, hetrombopag yielded high response rates, even among patients who had previously shown limited response to eltrombopag. However, these observations need to be confirmed in future trials.

ACVIM consensus statement on the diagnosis of immune thrombocytopenia in dogs and cats.

Immune thrombocytopenia (ITP) is the most common acquired primary hemostatic disorder in dogs. Immune thrombocytopenia less commonly affects cats but is an important cause of mortality and treatment-associated morbidity in both species. Immune thrombocytopenia remains a diagnosis of exclusion for which diagnostic guidelines are lacking. Primary, or non-associative, ITP refers to autoimmune platelet destruction. Secondary, or associative, ITP arises in response to an underlying disease trigger. However, evidence for which comorbidities serve as ITP triggers has not been systematically evaluated. To identify key diagnostic steps for ITP and important comorbidities associated with secondary ITP, we developed 12 Population Evaluation/Exposure Comparison Outcome (PECO) format questions. These questions were addressed by evidence evaluators utilizing a literature pool of 287 articles identified by the panelists using a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations that then were integrated by diagnosis and comorbidity domain chairs. The revised PECO responses underwent a Delphi survey process to reach consensus on final guidelines. A combination of panel expertise and PECO responses were employed to develop algorithms for diagnosis of ITP in dogs and cats, which also underwent 4 iterations of Delphi review. Comorbidity evidence evaluators employed an integrated measure of evidence (IME) tool to determine evidence quality for each comorbidity; IME values combined with evidence summaries for each comorbidity were integrated to develop ITP screening recommendations, which also were subjected to Delphi review. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The final consensus statement provides clinical guidelines for the diagnosis of, and underlying disease screening for, ITP in dogs and cats. The systematic consensus process identified numerous knowledge gaps that should guide future studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Treatment of Immune Thrombocytopenia.

Can COVID-19 Increase Platelet in Adult Immune Thrombocytopenia During the TPO-RA Administration? A Real-World Observational Study.

Introduction: COVID-19 infection has brought new challenges to the treatment of adult patients with immune thrombocytopenia (ITP). In adult ITP patients, there have been no relevant reports exploring the incidence, clinical characteristics, and risk factors of platelet elevation after COVID-19 infection. Materials and Methods: A total of 66 patients with previously diagnosed ITP from December 2022 to February 2023 in a single-center were collected and analyzed for this real-world clinical retrospective observational study. Results: In the platelet count increased group (n = 19), 13 patients (68.4%) were using thrombopoietin receptor agonists (TPO-RA) treatment at the time of COVID-19 infection; the median platelet count was 52 (2-207) ×109/L at the last visit before infection and 108 (19-453) ×109/L at the first visit after infection. In the platelet count stable group (n = 19) and platelet count decreased group (n = 28), 9 (47.4%) and 8 (28.6%) patients were using TPO-RA at the time of infection, respectively. ITP patients treated with TPO-RA had a significantly higher risk of increased platelet count than those not treated with TPO-RA at the time of infection (platelet count increased group vs platelet count decreased group: OR: 5.745, p = 0.009; platelet count increased group vs the non-increased group: OR: 3.616, p = 0.031). In the platelet count increased group, the median platelet count at 6 months post-infection was 67 (14-235) × 109/L, which was significantly higher than the platelet level at the last visit before infection (p = 0.040). Conclusion: This study showed that some adult ITP patients had an increase in platelet count after COVID-19 infection, and this phenomenon was strongly associated with the use of TPO-RA at the time of infection. Although no thrombotic events were observed in this study, it reminds clinicians that they should be alert to the possibility of thrombotic events in the long-term management of adult ITP patients during the COVID-19 pandemic.

Aplastic Anemia With Thrombosis Following the Administration of Immunosuppressant and Thrombopoietin Receptor Agonist (TPO-RA).

Thrombopoietin receptor agonist (TPO-RA) is effective for aplastic anemia (AA) and idiopathic thrombocytopenic purpura (ITP). However, the risk of thrombosis during ITP treatment with TPO-RA is higher than without TPO-RA. It is unclear whether TPO-RA increases the risk of thrombosis in patients with AA. We report a case of a 66-year-old female with severe AA having paroxysmal nocturnal hemoglobinuria (PNH) clones in the peripheral blood who developed ischemic colitis after three days of starting eltrombopag. Contrast-enhanced computed tomography showed ischemic colitis and contrast enhancement defect in the left atrial appendage, which indicated a thrombus in the heart. Stopping eltrombopag and providing supportive care improved her symptoms, and her blood cell counts gradually increased. Thrombosis should be considered when TPO-RA is administered during the immunosuppressive treatment of AA.

Data mining and safety analysis of avatrombopag: a retrospective pharmacovigilance study based on the US food and drug administration's adverse event reporting system.

With its increasing use in the treatment of thrombocytopenia, avatrombopag's associated adverse events (AEs) pose a major challenge to its clinical application. This study aims to comprehensively study AEs associated with avatrombopag by using real-world evidence. We curated AE reports for avatrombopag from the first quarter of 2018 to the fourth quarter of 2023 in the US Food and Drug Administration's Adverse Event Reporting System (FAERS) database. AEs were coded using the Medical Dictionary for Regulatory Activities of Preferred Terms and System Organ Classes. The reporting odds ratio, proportional reporting ratio, Bayesian confidence propagation neural network, and multi-item Gamma-Poisson Shrinker were used to investigate the relationship between avatrombopag and AE reports. Among 9,060,312 reported cases in the FAERS database, 1211 reports listed avatrombopag as "primary suspected" drug. Disproportionality analysis identified 44 preferred terms across 17 organ systems met the criteria for at least one of the four algorithms. The most commonly reported AEs were platelet count decreased (20.2%), headache (16.7%), platelet count increased (11.9%), platelet count abnormal (6.3%), contusion (2.7%), pulmonary embolism (2.3%), and deep vein thrombosis (2.1%). Unexpected AEs such as seasonal allergy, rhinorrhea, antiphospholipid syndrome, ear discomfort, and photopsia were also observed. Excluding the other serious outcomes, hospitalization (34.6%) was the most frequently reported serious outcome, followed by death (15.4%). Most reported AEs occurred within the first 2 days of initiating avatrombopag therapy, and the median onset time was 60 days. We identified new and unexpected AEs with clinical use of avatrombopag, and our results may provide valuable information for clinical monitoring and identifying risks associated with avatrombopag.