Stem cell harvesting after bortezomib-based re-induction for myeloma relapsing after autologous transplant: results from the BSBMT/UKMF Myeloma X (Intensive) trial.

Abstract

The phase III BSBMT/UKMF Myeloma X trial (MMX) demonstrated prospectively, for the first time, superiority of salvage autologous stem cell transplantation (ASCT2) over chemotherapy maintenance for multiple myeloma (MM) in first relapse after prior ASCT (ASCT1). However, many patients have insufficient stored stem cells (PBSC) for ASCT2 and robust evidence for remobilisation after ASCT1 is lacking. We therefore report on the feasibility, safety and efficacy of remobilisation after bortezomib-doxorubicin-dexamethasone reinduction in MMX, and outcomes of ASCT2 with these cells. 110 patients underwent ≥1 remobilisation with 32 and 4 respectively undergoing second and third attempts. Toxicities of remobilisation were similar to those seen in first line mobilisation. After all attempts, 52% of those with insufficient previously stored PBSC had harvested sufficient to proceed to ASCT2. Median PBSC doses infused, neutrophil engraftment and time to discharge after ASCT2 were similar irrespective of stem cell source, as were the toxicities of ASCT2. No significant differences between PBSC sources were noted in depth of response to ASCT or time to progression. Harvesting after bortezomib-doxorubicin-dexamethasone re-induction for MM at first relapse is safe and feasible, and yields a reliable cell product for second ASCT. The study is registered with ClinicalTrials.gov (NCT00747877) and EudraCT (2006-005890-24).