Second Autologous Stem Cell Transplant As Salvage Therapy For Multiple Myeloma

Abstract Introduction Therapeutic options for patients with multiple myeloma whose disease has relapsed after a prior autologous SCT include novel agents, traditional chemotherapy or a second transplant, with no clear standard of care. Limited data are available regarding the value of salvage therapy with a second autologous SCT in patients who relapse after the first one, and the factors that determine the outcome of the second SCT. We retrospectively reviewed our experience at Saskatoon Cancer Center with salvage autologous SCT for relapsed multiple myeloma. Methods Thirty three patients had received a salvage auto-SCT at our institution between February 2000 to February 2012. Median age at second SCT was 60 years (range; 46-71), Median time to relapse after the first SCT was 32 months (range; 3-80). Median interval between the first and second transplant was 34 months (range; 4-85). Re-induction therapy prior to second transplant contained combination with novel therapies (Bortezomib , lenalidomide or Thalidomide) in Thirteen patients ( 40 %) and the rest received conventional combination chemotherapies. Median line of therapies before the second SCT was 1 (range 0-3) with 23 patients (70%) received less than 2 lines and 30% received more than 2 lines. Results Responses to second autologous SCT at day 100 showed CR in 21%, VGPR 30 %, PR 42% with ORR 93 %. Non relapse mortality at day 100 after second transplant was 3 % (no= 1) With a median follow up time of 24 months (range 1-99) from the salvage SCT, the median PFS was 27 months (range 1-89) and the median overall survival (OS) was 36 months ( range 1-99) Eleven patients had TTP inversion (PFS longer after the second transplant) with a median increase of 18 months , of note only two of them received novel agents for salvage, but 70 % required less than two lines prior to salvage SCT. In univariate analysis, patients who had received < 2 lines of therapy prior to salvage SCT (23/33) had significantly higher median TTP of 31 and OS of 52 months, compared to 19 and 33 months for patients who had received ≥2 lines of therapy (10/33). (P = 0.04) Patients who had relapsed more than 2 years post 1st SCT (18/33) had a significantly higher median TTP and OS of 27 and 39 months respectively compared to 22 and 24 months patients who had relapsed less or equal to 2 years (15/33) (P= 0.04) In multivariate analysis, only response to salvage SCT > PR had an impact on TTP and OS; however it was not statistically significant. Conclusion Second salvage auto-SCT generally is safe and effective in patients with relapsed multiple myeloma. Patients with ≥2 prior lines of therapy and a TTP after initial transplant of ≤24 months are unlikely to benefit significantly. Salvage auto-SCT should therefore be considered for appropriate patients with relapsed multiple myeloma. Disclosures: No relevant conflicts of interest to declare.