Avatrombopag for post‐transplant thrombocytopenia following allogeneic haematopoietic stem cell transplantation: A single‐centre retrospective study

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is potentially curative for high-risk haematological diseases but may lead to persistent cytopenias such as poor graft function (PGF) or graft failure (GF). Thrombopoietin receptor agonists (TPO-RAs) like eltrombopag or romiplostim are effective but have pharmacologic and practical limitations. This retrospective study evaluated avatrombopag, a novel oral TPO-RA, in 11 adult patients with persistent thrombocytopenia following allo-HSCT (8 with PGF and 3 with GF). Avatrombopag was initiated at 20 mg/day orally, escalated to 40 mg/day after a median of 21 days and up to 60 mg/day after a median of 36 days as the maximum dose in patients who did not achieve an adequate response. The median time to response was 55 days, with a median treatment duration of 134 days. A haematological response was achieved in all eight patients with PGF, with significant improvements in platelet counts and other haematopoietic lineages. In contrast, no response was documented in patients with GF. No severe adverse events or complications were reported. Notably, these findings suggest that avatrombopag is a promising alternative for PGF, offering practical advantages over other TPO-RAs, although prospective studies are needed with a larger sample size of patients to confirm these results.