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.

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 3 years. 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 2 weeks), 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.

UNASSIGNED: Eltrombopag (EPAG), a thrombopoietin receptor agonist, was approved for the treatment of severe aplastic anemia (SAA) combined with immunosuppressive therapy (IST). However, EPAG contains a typical biphenyl structure, which causes liver function damage.
UNASSIGNED: Twenty patients with SAA who were intolerant or refractory to EPAG were enrolled in a multicenter prospective registry of the Chinese Eastern Collaboration Group of Anemia (ChiCTR2100045895) from October 2020 to June 2023.
UNASSIGNED: Eight patients who were ineffective to EPAG, six with kidney impairment, and nine with abnormal liver function (two with concomitant liver and kidney impairment) were converted to avatrombopag (AVA) therapy with the median duration of AVA treatment was 6 (3-24) months. 17 cases (85%) achieved trilineage hematological response (HR): complete remission (CR) in 3 cases (15%), good partial remission (GPR) in 4 cases (20%), partial remission (PR) in 10 cases (50%), and no response (NR) in 3 cases (15%). The median time to response was 1.7 (0.5-6.9) months, with 16 cases (94%) achieving response within six months and 17 cases (100%) within 12 months. 9 cases (50%) achieved transfusion independence. AVA converted treatment was associated with higher neutrophil counts (0.8×109/L vs 2.2×109/L, p=0.0003), platelet counts (11×109/L vs 39×109/L, p=0.0008), hemoglobin count (59g/L vs 98g/L, p=0.0002), red cell count (1.06×1012/L vs 2.97×1012/L, p=0.001), and absolute reticulocyte count (31.99 ×109/L vs 67.05×109/L p=0.0004) were all significantly elevated compared with the pre-treatment level. After the conversion to AVA therapy, liver and kidney function indexes were maintained within the normal range, no AVA related grade 2 or higher adverse events occurred, and no thrombotic events occurred.
UNASSIGNED: The conversion to AVA was an optimal choice for patients with SAA who were EPAG intolerant or refractory.
UNASSIGNED: http://www.chictr.org.cn/showproj.html?proj=125480, identifier ChiCTR2100045895.

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.

UNASSIGNED: Platelet transfusion refractoriness (PTR) is a life-threatening and intractable condition in hematological patients. Thrombopoietin receptor agonists such as avatrombopag promote platelet production and modulate immune intolerance. However, its application in PTR has not been extensively studied.
UNASSIGNED: We aimed to compare the platelet response (PR) as well as bleeding events and mortality rate between the best available therapies (BATs) and avatrombopag (Ava) treatments in refractory PTR patients.
UNASSIGNED: A total of 71 refractory PTR patients were enrolled at Nanfang Hospital. Intravenous immunoglobulin, steroids, and human leucocyte antigen-matched platelet transfusions were administered to 30 patients in the BATs group. The Ava group included 41 patients.
UNASSIGNED: Data of refractory PTR patients were retrospectively collected. The primary endpoint was PR (defined as an increase of platelet count to ⩾50 × 109/L without platelet transfusion support for 7 consecutive days). Secondary endpoints included platelet-transfusion independence rate, cumulative platelet transfusion units, World Health Organization bleeding grades, adverse events, overall survival (OS), and bleeding event-free survival (EFS).
UNASSIGNED: There were 75.6% and 13.3% refractory PTR patients who reached PR within 3 months in Ava and BATs groups. The median platelet counts were significantly higher in Ava group from day 7. Platelet-transfusion independence rate in Ava was higher than BATs group. The median cumulative platelet transfusion unit in Ava was lower than that of BATs group. The OS and bleeding events-free EFS rate of Ava group improved within 3 months as compared to BATs group. Cox proportional hazards regression analysis revealed that Ava therapy was a protective factor for the OS and EFS. No primary disease progression or termination of avatrombopag was observed due to intolerability.
UNASSIGNED: Our study suggests that avatrombopag is an effective and safe treatment option for refractory PTR patients.
Avatrombopag in platelet transfusion refractoriness PTR is a challenging clinical issue in patients with hematologic disorders which increases early death and hospitalization costs. Thrombopoietin receptor agonists have shown inspiring effects in treating thrombocytopenia. However, there are few studies focused on the application of these drugs in PTR patients. In this study, we investigated 71 patients with PTR in which 30 patients received the best available therapies, while 41 patients received avatrombopag treatment. We found that avatrombopag increases platelet response rate, reduces platelet transfusions dependence and occurrence of severe bleeding events, as well as improves overall survival rate and event free survival in PTR patients. Avatrombopag also exhibited good tolerance and safety. We reported for the first time that avatrombopag was an effective and safe treatment in PTR, which may also help to expand the clinical application of TPO-RAs.

Carboplatin/pegylated liposomal doxorubicin/bevacizumab is an accepted standard anti-cancer treatment option for recurrent ovarian cancer. However, the occurrence of adverse events associated with this therapeutic regimen limits its continued clinical use. Among these adverse events, acquired amegakaryocytic thrombocytopenia is a rare but often potentially life-threatening adverse effect, and is intolerant to multiple treatment approaches. We report, for the first time, the successful treatment using avatrombopag combined with cyclosporine in one case of carboplatin/pegylated liposomal doxorubicin/bevacizumab-induced acquired amegakaryocytic thrombocytopenia, which was refractory or intolerant to glucocorticoids, intravenous immunoglobulin, recombinant human thrombopoietin, androgen, and even thrombopoietin receptor receptor agonist eltrombopag and herombopag. To date, this case manifests as normal platelet counts that are independent of transfusion. Our findings suggest that this combination is a potential and valuable alternative in acquired amegakaryocytic thrombocytopenia.

Avatrombopag (AVA) is a novel thrombopoietin receptor agonist (TPO-RA) that has been recently approved as a second-line therapy for immune thrombocytopenia (ITP) in adults; however, its safety and efficacy data in children are lacking. Here, we demonstrated the efficacy and safety of AVA as second-line therapy in children with ITP. A multicentre, retrospective, observational study was conducted in children with persistent or chronic ITP who did not respond to or relapsed from previous treatment and were treated with AVA for at least 12 weeks between August 2020 and December 2022. The outcomes were the responses (defined as achieving a platelet count ≥30 × 109/L, twofold increase in platelet count from baseline and absence of bleeding), including rapid response within 4 weeks, sustained response at weeks 12 and 24, bleeding control and adverse events (AEs). Thirty-four (18 males) patients with a mean age of 6.3 (range: 1.9-15.3) years were enrolled. The median number of previous treatment types was four (range: 1-6), and 41.2% patients switched from other TPO-RAs. Within 4 weeks, overall response (OR) was achieved in 79.4% patients and complete response (CR, defined as a platelet count ≥100 × 109/L and the absence of bleeding) in 67.7% patients with a median response time of 7 (range: 1-27) days. At 12 weeks, OR was achieved in 88.2%, CR in 76.5% and sustained response in 44% of patients. At 24 weeks, 22/34 (64.7%) patients who achieved a response and were followed up for 24 weeks were evaluated; 12/22 (54.55%) achieved a sustained response. During AVA therapy, median platelet counts increased by week 1 and were maintained throughout the treatment period. The proportion of patients with grade 1-3 bleeding decreased from 52.95% at baseline to 2.94% at 12 weeks, while concomitant ITP medications decreased from 36.47% at baseline to 8.82% at 12 weeks, with only 9 (26.47%) patients receiving rescue therapy 23 times within 12 weeks. There were 61.8% patients with 59 AEs: 29.8% with Common Terminology Criteria for Adverse Events grade 1 and the rest with grade 2. These findings show that AVA could achieve a rapid and sustained response in children with persistent or chronic ITP as a second-line treatment, with good clinical bleeding control and reduction of concomitant ITP therapy, without significant AEs.

BACKGROUND: Pure red cell aplasia (PRCA) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) with ABO major incompatibility is characterized by transfusion dependent anemia. No standard treatment existed for PRCA following allo-HSCT yet.
METHODS: We conducted a retrospective study, and reported our experience with the use of avatrombopag and lower dose rituximab to treat five patients with PRCA subsequent to major ABO-incompatible allo-HSCT.
RESULTS: Five cases of PRCA were identified from 72 patients who underwent allo-HSCT with major or bidirectional ABO mismatch. Cumulative incidence at Day +60 was 6.9% (5/72) at our center. All donor and recipient blood groups were A+  and O+ , respectively. In the first three cases we reported, patients received erythropoietin, plasma exchange, and donor lymphocyte infusion, but none of them had any effect. After 4 weeks of treatment with low dose rituximab (100 mg/week) combined with avatrombopag (40 mg/day), favorable outcomes were obtained. According to the aforementioned experience, Cases 4 and 5 were administered low-dose rituximab and avatrombopag in 3 months after transplantation, and erythroid response was observed on 3 weeks after treatment. Our patients tolerated low-dose rituximab and avatrombopag well and experienced rapid efficacy, with a median duration of 3 weeks. Furthermore, no severe infection or thrombocytosis necessitated a dose adjustment.
CONCLUSIONS: Low-dose rituximab and avatrombopag may be an effective treatment for patients with PRCA after major ABO-incompatible allo-HSCT. The patients should be treated at least 90 days post transplantation if conventional erythropoietin therapy fails.

UNASSIGNED: Thrombopoietin-receptor agonist (TPO-RAs) currently represent the state of art for treating immune thrombocytopenia. Their different molecular structures contribute to the difference in their pharmacodynamics and pharmacokinetics. This narrative review aims to provide an overview of the current TPO-RAs approved for primary immune thrombocytopenia (romiplostim, eltrombopag, avatrombopag) and the effect of intermittent fasting in adult patients receiving TPO-RAs.
UNASSIGNED: Literature was searched with no limits on date or language, using various combinations of keywords. Data on the pharmacokinetics, pharmacodynamics, efficacy, and safety of TPO-RAs and the effect of intermittent fasting were summarized.
UNASSIGNED: Switching between TPO-RAs is a useful strategy to tackle some associated limitations. Romiplostim and avatrombopag have an advantage over eltrombopag as they do not require any dietary restrictions. In cases where romiplostim and avatrombopag are unavailable, patients should be educated on the appropriate administration, possible interactions, and dietary restrictions before initiating eltrombopag.

Chemotherapy-induced thrombocytopenia (CIT) is a common complication of antineoplastic therapy, resulting in antineoplastic therapy dose reductions, treatment delays, treatment discontinuation, and morbid bleeding events. Despite several decades of research into thrombopoietic growth factors in CIT, there are presently no available U.S. FDA- or EMA-approved agents to treat CIT. However, a respectable body of evidence has been published evaluating the thrombopoietin receptor agonists (TPO-RAs) for the management and prevention of CIT in patients with solid tumors, and critical studies are ongoing with the TPO-RAs romiplostim and avatrombopag. When employed in the appropriate patient population and used properly, TPO-RAs can successfully and safely manage CIT for extended periods of time with minimal apparent risks. This comprehensive review discusses the evidence for TPO-RAs in CIT in patients with solid tumors, provides detailed guidance for their use in the clinic, and discusses ongoing essential clinical trials in management of CIT.