Outcomes of second hematopoietic stem cell transplantation using reduced‐intensity conditioning in an outpatient setting

Relapse and graft failure after autologous (auto) or allogeneic (allo) hematopoietic stem cell transplantation (HSCT) are serious and frequently fatal events. A second HSCT can be a life‐saving alternative, however, information on the results of such intervention in an outpatient setting is limited. Outpatient second hematoprogenitors transplant after reduced‐intensity conditioning (RIC) at a single academic center was analyzed. Twenty‐seven consecutive adults who received an allo‐HSCT after an initial auto‐ or allo‐HSCT from 2006 to 2019 were included. Data were compared using the χ 2 ‐test. Survival analysis using Kaplan–Meier and Cox proportional hazard models was performed; cumulative incidence estimation of transplant‐related mortality (TRM) was assessed. Hodgkin lymphoma was the most frequent diagnosis for the group with a first auto‐HSCT with 5/12 (41.7%) cases, and acute myeloid leukemia for those with a first allo‐HSCT with 6/15 (40%). One‐year overall survival and disease‐free survival (DFS) was 66.7% (95% CI 27.2–88.2) and 59% (95% CI 16–86) for 12 patients with a first auto‐HSCT; and for 15 patients with a first allo‐HSCT, it was 43.3% (95% CI 17.9–66.5) and 36% (95% CI 13.2–59.9), respectively. Eight (29.6%) patients died of TRM and the cumulative incidence of TRM at 1 year was 22% (95% CI 8.6–39.27). Chronic graft‐versus‐host disease and late (>10 months) second transplantation were protective factors for longer survival. Neutropenic fever was more common in the group with a first allo‐HSCT ( p = 0.01). In conclusion, outpatient second allo‐HSCT using RIC after auto‐ or allografting failure or relapse is feasible and offers a reasonable alternative for patients with severe life‐threatening hematological diseases.