Carfilzomib, Lenalidomide, and Dexamethasone Followed by Salvage Autologous Stem Cell Transplant with or without Maintenance for Relapsed or Refractory Multiple Myeloma

SIMPLE SUMMARY: High-dose chemotherapy and autologous stem cell transplantation (HDCT/ASCT) is a standard treatment in patients with newly diagnosed multiple myeloma (MM). At relapse, salvage HDCT/ASCT is a treatment option in patients with sufficient benefit from frontline HDCT/ASCT, but no evidence is currently available regarding its role in the era of triplet regimens combining the most active drug classes for relapsed MM. To evaluate the outcome after salvage HDCT/ASCT following re-induction treatment with carfilzomib/lenalidomide/dexamethasone (KRD) and to identify prognostic factors, we conducted a retrospective analysis of patients that had previously undergone frontline HDCT/ASCT. We found that deep remissions achieved with KRd followed by salvage autologous transplantation were associated with favorable PFS and were enhanced by maintenance treatment. Salvage autologous transplantation after state-of-the-art triplet re-induction was a safe and effective strategy for RRMM patients that may offer the chance to avoid refractoriness to multiple novel agents at the next relapse. ABSTRACT: Salvage high-dose chemotherapy and autologous stem cell transplantation (HDCT/ASCT) is a treatment option for relapsed and/or refractory multiple myeloma (RRMM). No data are available on salvage HDCT/ASCT following re-induction treatment with state-of-the-art triplet regimens. We retrospectively report on 44 patients receiving salvage HDCT/ASCT following re-induction with carfilzomib/lenalidomide/dexamethasone (KRd). All patients received frontline HDCT/ASCT with median time to progression (TTP1) of 2.9 (1.2–13.5) years, enabling paired comparison of frontline and salvage HDCT/ASCT. After re-induction and before salvage transplant, 25/44 patients (57%) attained ≥ very good partial response (VGPR), which increased to 34/44 (77%) at best response after salvage HDCT/ASCT. Median progression-free survival (PFS) was 23.3 months from salvage HDCT/ASCT. Patients with ≥ VGPR at the time of salvage HDCT/ASCT and those receiving maintenance treatment post salvage HDCT/ASCT had significantly superior PFS (hazard ratio (HR) 0.19, p = 0.001 and HR 0.20, p = 0.009). In patients achieving at least an equal depth of response before salvage HDCT/ASCT as before frontline HDCT/ASCT, PFS after salvage HDCT/ASCT was comparable to the frontline situation (p = 0.3). This is the first report of state-of-the-art triplet re-induction and salvage HDCT/ASCT for RRMM after frontline transplantation. Deep remissions achieved with KRd translate into prolonged PFS following salvage HDCT/ASCT and are enhanced by maintenance treatment.