Eltrombopag Improved Cytopenias Due to Posttransplant Poor Graft Function: Experience from a Comprehensive Bone Marrow Transplantation Program in Jordan

Introduction Poor graft function (PGF) is a serious complication of allogeneic stem cell transplantation (allo-SCT). Current therapies are only partially effective. There are eight reports of eltrombopag given to improve posttransplant graft function with encouraging results. Methods This is a retrospective study to assess the effectiveness of eltrombopag, in the treatment of PGF following allo-SCT. 23 patients were included. Results Between Jan 2013 -Jan 2023, 30 of 1112 consecutive allotransplant recipients (2.7%) developed PGF. Seven patients received 2nd transplant, 23 eltrombopag. Thirteen were female. Median age was 47y (26–68 y). Fourteen received RIC pretransplant conditioning. Fourteen donors were HLA-identical siblings, and nine HLA-haplotype-matched relatives. Median Hb concentration before eltrombopag 8.5g/dL (6–14.2 g/dL), - Grans 7.1 × 10E + 9/L (1.6, 85 × 10E + 9/L), platelets 18 × 10E + 9/L (6–50 × 10E + 9/L). Thirteen subjects had platelets < 20 × 10E + 9/L, 15 had decreased megakaryocytes. Median CD34-positive cell dose 6.10 × 10E + 6/kg (2.75 –9.78 × 10E + 6/kg). Median interval between transplant and starting eltrombopag 93 d (230–800 d). Median weekly eltrombopag dose 488mg (350–700 mg/week) and median treatment duration 75 d (5–446 d).The overall response rate 65% (n-15). Median interval to response was 30 d (7–122 d).Adequate bone marrow megakaryocytes was a predictor of response (P-0.019 ). Preserved graft function was significantly better in responders at 2 years (67% vs 12.5%; P-0.0001). The 12 of responders are alive at a median follow up of 30 months (7–122months) with normal blood cell concentrations. The median overall survival (OS) was 23 months (9-NR). 2-year OS 48% (range:27%, 70%). Seven nonresonders died, none due to relapse. There were no major adverse events.Conclusion eltrombopag improves peripheral blood counts in patients with PGF following allotransplant. Response to eltrombopag can be predicted and has a significant impact on survival.