Second hematopoietic stem cell transplantation as salvage therapy for relapsed acute myeloid leukemia/myelodysplastic syndromes after a first transplantation

Abstract

Second allogeneic hematopoietic stem-cell transplantation (HSCT2) is a therapeutic option for patients with AML/ MDS relapsing after a first transplant (HSCT1). However, patients allocated to HSCT2 may be a selected group with better prognosis and the added efficacy of HSCT2 is not well established. We retrospectively analyzed 407 consecutive patients with relapsed AML/MDS after HSCT1. Sixty-two patients had HSCT2 (15%) and 345 did not. The 2-year cumulative incidence rates of non-relapse mortality and relapse after HSCT2 were 26% (95% CI, 17-39%) and 50% (95% CI, 39-65%), respectively. The 5-year overall survival (OS) rates were 25% (95% CI, 14-36%) and 7% (95% CI, 4-10%) in the HSCT2 and no-HSCT2 groups, respectively. Multivariate-analysis identified female gender (HR 0.31, P=0.001), short remission duration after HSCT1 (HR 2.31, P=0.05), acute GVHD after HSCT1 (HR 2.27, P=0.035), HSCT2 from haplo-identical (HR 13.4, P=0.001) or matched-unrelated donor (HR 4.53, P=0.007) and relapse after HSCT1 in earlier years (HR 2.46, P=0.02) as factors predicting OS after HSCT2. Multivariate-analysis of all patients including HSCT2 entered as time-dependent variable identified relapse within 6 months after HSCT1 (HR 2.32, P<0.001), acute GVHD before relapse (HR 1.47, P=0.005), myeloablative conditioning in HSCT1 (HR 0.67, P=0.011), female gender (HR 0.71, P=0.007), relapse in earlier years (HR 1.33, P=0.031) and not having HSCT2 (HR 1.66, P=0.010) as predictive for OS after relapse. In conclusion, HSCT2 is associated with longer survival compared to non-transplant treatments and may be the preferred approach in a subset of patients with relapsed AML/MDS after HSCT1.