Eltrombopag May Improve Platelet Recovery in the Outpatient Setting after Allogeneic Stem Cell Transplant

Introduction Thrombocytopenia after allogeneic stem cell transplant (HCT) is multifactorial in etiology and may require long term transfusion care support. Eltrombopag (TPO) is sometimes used off-label in the post HCT setting to treat poor graft function and thrombocytopenia, however data is limited to small retrospective cases/series. We present our single institution experience. Objective Our objective was to describe the outcomes of pts treated with TPO for post-HCT primary and second failure of platelet recovery (FPR), defined as platelet Methods We retrospectively reviewed charts of HCT patients who received TPO post HCT from 1/1/13 to 10/1/19. We excluded patients who had active, identified relapse at the time of TPO initiation. We examined clinical characteristics and outcomes of those receiving TPO. Results Thirty-four patients received TPO for primary (22) and secondary (12) FPR. 6 had BM grafts, and 15 had alternative donors (mismatch or haplo). Median time to start of TPO was D+79 (range 21-341). Among 16/34 TPO responders, median time to response was 49 days (range 7-166). In responders, GvHD (10), infection (8) and ITP (6) were well represented as potential etiologies. 18 (53%) patients were started on TPO as inpatients with only 4/18 (22%) responses. Outpatient TPO starts had 12/16 (75%) responses. Relapsed disease was eventually diagnosed after TPO in 9/34 (26%) pts at median 44 days (range 11-280), with full donor chimerism in all relapsed pts prior to TPO. Among those with relapse, 3/9 (33%) patients had response to TPO. Conclusion TPO may facilitate platelet recovery, particularly in the outpatient setting. Inpatients had limited benefit from TPO likely due to multiple life threatening infectious and immunologic issues. The frequency of relapses seen after TPO should alert the clinician to assess disease status when considering initiation.