High-dose chemotherapy followed by autologous stem cell transplant for multiple myeloma: Predictors of long-term outcome.

Background & objectives: Survival of patients with multiple myeloma (MM) has improved in the past two decades following use of novel agents and autologous stem cell transplantation. To determine predictors of long-term outcome, data of MM patients who underwent autologous stem cell transplantation (ASCT) at a tertiary care centre in north India were retrospectively analyzed.
Methods: Between 1995 and 2016, 349 MM patients underwent ASCT. Patients' median age was 52 yr, ranging from 29 to 68 yr, 68.2 per cent were males. Thirty three per cent patients had international staging system (ISS) Stage III and 68.5 per cent had received novel agents-based induction. High-dose melphalan (200 mg/m2) was used for conditioning; patients with renal insufficiency (estimated glomerular filtration rate <40 ml/min) received melphalan 140-150 mg/m2.
Results: Post-transplant, 317 of 349 (90.8%) patients responded; complete [complete response (CR)] -213 (61%)], very good partial response (VGPR) -62 (17.8%) and PR in 42 (12%)]. Induction with novel agents, pre-transplant chemosensitive disease, transplant in first remission and serum albumin (≥3.5 g/dl) were predictors of significant response. At a median follow up of 73 months, median overall survival (OS) was 90 months [95% confidence interval (CI) 70.8-109.2], and progression-free survival (PFS) was 41 months (95% CI 33.0-49.0). On multivariate analysis, achievement of CR post-transplant, transplant in first remission, ISS Stages I and II (vs. III), absence of extramedullary disease and serum albumin ≥3.5 g/dl were predictors of prolonged OS. For PFS, achievement of post-transplant CR and transplant in first remission were predictors of superior outcome. Interpretation & conclusions: Treatment with novel agents, achievement of complete remission post-transplant, ISS Stages I and II, absence of extramedullary disease and transplant in first remission were predictors of long-term survival for patients with MM.