Outcomes of patients with acute leukaemia who relapsed after reduced‐intensity stem cell transplantation from HLA‐identical or one antigen‐mismatched related donors

Summary The characteristics of relapse following reduced‐intensity stem‐cell transplantation (RIST) remain to be clarified. We reviewed the medical records of 19 patients with acute leukaemia [acute myeloid leukaemia (AML), 16; acute lymphoblastic leukaemia (ALL), 3] who relapsed after RIST from related donors using purine‐analogue‐based regimens. Their median age was 55 years (range, 29–65 years). Median interval between RIST and relapse was 4·9 months (range, 1·8–24·9 months). Three chose not to receive interventions. The remaining 16 patients received withdrawal of immunosuppression (n = 3), chemotherapy (n = 2), donor lymphocyte infusion (n = 10) and second transplantation (n = 7), alone (n = 9) or in combination (n = 7). Four are alive with a median follow‐up of 27·6 months (range, 16·0–28·9 months); three in remission and one in relapse. The 2‐year overall survival after relapse was 28·9%. Causes of death in 15 patients included progressive disease (n = 7), graft‐versus‐host disease (n = 5) and infections (n = 3). Cumulative incidences of relapse‐related and non‐relapse‐related deaths at 2 years after relapse were 37% and 32% respectively. Two prognostic factors were identified on univariate analysis: age [P = 0·017; hazard ratio (HR), 1·16; 95% confidence interval (CI), 1·03–1·32], and ALL as underlying disease (P = 0·011; HR, 10·4; 95% CI, 1·73–62·4). Some AML patients who relapse after RIST achieve durable remission with allogeneic immunotherapy‐based interventions; however they carry a significant risk of non‐relapse mortality.