Complete response after autologous stem cell transplant in multiple myeloma

Abstract

We evaluated long-term outcome of patients achieving complete response (CR) after autologous stem cell transplantation (ASCT) for multiple myeloma. Between April 1990 and June 2012 191 patients underwent ASCT. The median age was 53 years (range, 26–68 years), 135 were men. Pretransplant, patients received induction therapy with VAD (vincristine, doxorubicin, dexamethasone; n = 77), novel agents (n = 92), or alkylating agent-based, n = 22); 43% received more than one line of induction regimen. Response to transplant was defined as per EBMT criteria. The median follow-up for the entire group was 85 months (range, 6–232.5 months). Following transplant 109 (57.1%) patients achieved CR. Median progression-free survival (PFS) for patients with CR was higher compared to those with VGPR and PR, (107 vs. 18 vs. 18 months, P < 0.001). Number of lines of therapy pretransplant (one or two vs. more than two lines of therapy (P < 0.001), and absolute lymphocyte count of ≤3000/cmm were predictors of superior PFS. Median overall survival (OS) for patients with CR was higher, (204 months), compared to those with VGPR (71.5 months, P < 0.001) and PR (51.5 months, P < 0.001), respectively. On Cox regression analysis, patients who received one line of induction therapy pretransplant (hazard ratio, HR 2.154, P < 0.001) and those with absolute lymphocyte count of ≤3000/mm³ (HR 0.132, P < 0.001) had superior PFS. For overall survival, induction treatment up to one line (HR 2.403, P < 0.004) and Hb > 7.1 G/dL at diagnosis (HR 4.756, P < 0.01) were associated with superior outcome. On landmark analysis at 12 months, PFS and OS continued to remain superior for patients attaining CR. Achievement of CR post transplant is associated with longer OS and PFS. Among complete responders, those who receive one line of induction therapy pretransplant have superior outcome.