Lusutrombopag improves platelet engraftment after autologous haematopoietic stem cell transplantation in multiple myeloma: A single-centre retrospective study

Abstract Abstract Title: Lusutrombopag Improves Platelet Engraftment after Autologous Haematopoietic Stem Cell Transplantation in Multiple Myeloma: A Single-Centre Retrospective Study Background Multiple myeloma (MM) is the second most common haematological malignancy globally, with >170,000 annual cases. Over 90% of eligible patients require autologous haematopoietic stem cell transplantation (ASCT) as standard therapy. Delayed platelet engraftment remains a frequent post-transplant complication, increasing haemorrhagic risk and potentially contributing to mortality. This delay may lead to platelet transfusion dependence/refractoriness, heightened transfusion reactions, prolonged hospitalisation, increased healthcare costs, and reduced quality of life. Currently, no pharmacologic interventions are approved, with reliance solely on platelet transfusions (response rate <60%), underscoring the need for safe, proactive strategies. Objective This study aimed to evaluate the effect of lusutrombopag on platelet engraftment time post-ASCT in MM patients, providing evidence-based support for optimised transplantation management. Methods This single-centre retrospective study enrolled 24 MM patients treated at China-Japan Union Hospital of Jilin University between 1 December 2024 and 1 August 2025. Patients were stratified into two cohorts: Lusutrombopag group (n=9): Received oral lusutrombopag 3mg/day (with meals) initiated when post-infusion platelet count first fell ≤50×10⁹/L, continued until engraftment (defined as platelet count ≥20×10⁹/L without transfusion for 7 consecutive days). Control group (n=15): Historical controls receiving standard care without lusutrombopag. Primary outcome: Time to platelet engraftment. Result Lusutrombopag accelerated platelet engraftment: Median engraftment time: 10 days (lusutrombopag) vs 12 days (controls) Cumulative incidence at day +13: Significantly higher in lusutrombopag group (P*=0.002; 95% CI: -3.5 to -1.0 days) ≤10-day engraftment rate: Significantly increased (OR=12.5; P*=0.006) Both groups exhibited favourable outcomes with no adverse events. Conclusion Lusutrombopag accelerates platelet engraftment post-ASCT in MM patients, reducing median time by 2 days and transfusion requirements, thereby optimising this critical treatment phase. Keywords: Lusutrombopag; Multiple myeloma; Autologous haematopoietic stem cell transplantation; Platelet engraftment; Retrospective study