A Single Autologous Stem Cell Transplant (Asct) Followed By Two Years Of Post-Transplant Therapy In Older Recently Diagnosed Multiple Myeloma (Mm) Patients. Safety And Response Results From The Prospective Phase Ii Trial (Nct01849783)

IntroductionWhile melphalan 200 mg/m2 has been the standard preparative regimen for ASCT, studies are currently evaluating the role of including novel agents along with melphalan to improve outcomes. We have previously reported outcomes in patients younger than 65 years who received intensive conditioning, ASCT, followed by triple maintenance therapy. This current prospective study evaluates the tolerance of this therapy in elderly patients older than 65. Here we report preliminary responses and safety outcomes.Methods and patientsA total of 41 eligible patients above the age 65 were prospectively enrolled in the IRB approved phase II trial beginning in June 2013. After induction chemotherapy and stem cell collection, ASCT was performed with a preparative chemotherapy consisting of VDT-Melphalan 200 mg/m2. Early after engraftment, patients were started on maintenance for 2 years with triple agent therapy consisting of either a proteasome inhibitor (PI) or an immunomodulatory drug (Imid), along with steroids. Primary end points include PFS, frequency of severe toxicities, ICU admissions, and percentage of patients able to complete the full course of maintenance.ResultsThirty seven of the 41 patients enrolled received a single ASCT and were included in the analysis. Median age was 71 (range: 66 to 77). Twelve patients (59%) had standard risk cytogenetics and 15 patients (40%) had high risk cytogenetics by FISH. Median follow up was 26 months (range: 3 months – 5 years). Median time to neutrophil and platelet engraftment were both 11 days. There was one death within day 100 related to candida sepsis. Only 2 patients were re-hospitalized within 100 days but none required ICU admission. Median time to start post-transplant therapy was 73 days (range: 47 to 185 days). Best responses noted prior to initiation of maintenance were 17 sCR (47%), 3 CR (8%), 10 VGPR (28%) and 6 PR (17%). Thirty five patients (95%) were able to start on planned triple maintenance regimen. Twelve patients have completed 2 years of maintenance therapy at last follow up. A total of 3 patients died during maintenance phase due to progressive disease. Median PFS and OS were not reached and 3 year PFS and OS were 82 and 91%, respectively.ConclusionsThis is the first trial to prospectively evaluate the safety and efficacy of early ASCT in elderly MM patients using a novel agent conditioning regimen followed by a triple maintenance therapy consisting of either a PI or an Imid combination. These results indicate that the regimen is safe and well tolerated without any increased mortality, and results in a deep, sustained response rates. Longer follow up will determine the long term side effects of the regimen, disease responses and PFS in elderly patients.