Unmanipulated Haploidentical Hematopoietic Stem Cell Transplantation Achieved Outcomes Comparable With Matched Unrelated Donor Transplantation in Young Acquired Severe Aplastic Anemia

Salvage haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is considered in patients with severe aplastic anemia (SAA) if a matched unrelated donor (MUD) is unavailable. However, studies on haplo- and MUD transplantation in SAA are lacking. The present study retrospectively analyzed the outcomes of 89 young SAA patients who underwent unmanipulated alternative HSCT between September 2012 and September 2016 at our single center. Forty-one patients received haploidentical donors and forty-eight patients MUDs for HSCT. Most were heavily transfused and refractory to previous immunotherapy. The median durations for myeloid engraftment in the haplo- and MUD cohorts were 14 (range, 10 to 21) and 13 (range, 10 to 18) days, respectively. Compared with the MUD cohort, haplo-HSCT cohorts had an increased cumulative incidence of acute graft-versus-host disease (GVHD) grades II to IV (43.9% +/- 7.8% versus 12.5% +/- 4.8%, P = .001) and grades III to IV (21.1% +/- 6.7% versus 6.6% +/- 3.7%, P = .045) and similar limited chronic GVHD (47.7% +/- 8.5% versus 38.5% +/- 7.3%, P = .129) and extensive chronic GVHD (12.1% +/- 6.8% versus 9.1% +/- 4.3%, P = .198). The median follow-up time of the surviving patients was 26 months (range, 6 to 45). No significant differences were observed between haplo-HSCT and MUD HSCT cohorts in 3-year overall survival (80.3% +/- 5.1% versus 89.6% +/- 7.0%, P = .210), disease-free survival (76.4% +/- 5.1% versus 89.4% +/- 7.7%, P = .127), and GVHD-free failure-free survival (79.0% +/- 8.6% versus 71.6% +/- 9.3%, P = .976). Thus, haplo-HSCT, as salvage therapy, achieved similar outcomes as MUD HSCT in young SAA patients, thereby rendering it as an effective and safe option for SAA. (C) 2018 American Society for Blood and Marrow Transplantation.