P-355: Melphalan vs Carmustine, Etoposide, Cytarabine, and Melphalan (BEAM) as preparative regimen for newly diagnosed patients with Multiple Myeloma undergoing Autologous stem cell transplant.

Introduction: ASCT has been shown in multiple prospective randomized trials to result in superior progression-free survival (PFS), and in some studies, better overall survival (OS) for patients with multiple myeloma (MM). Prior comparisons between BEAM and MEL have been retrospective and suggest that BEAM may be more efficacious than MEL in MM. Here we present results of a prospective randomized trial between MEL and BEAM regimens for patients with MM undergoing transplant in first remission.

Methods: Patients with newly diagnosed MM without severe comorbidities, received at least 2 cycles of induction therapy with a minimum of partial response, were randomly assigned to receive either BEAM or MEL prior to ASCT. The clinical decision to treat patients using ASCT was made prior to study enrollment. Patients were stratified utilizing the following parameters: serum beta-2-microglobulin < 5 or ≥5, and the presence or absence of high-risk genetics as defined by IMWG criteria.

BEAM was administered in-patient as follows: Carmustine 300 mg/m2 IV day -7; Etoposide 100 mg/m2 IV days -6,-5,-4,-3; Cytarabine 100 mg/m2 IV BID on days -6, -5, -4 and -3; MEL 140 mg/m2 IV on day - 2. MEL was given at a dose of 200 mg/m2 IV on Day -2. Patients filled out quality of life questionnaires (FACT-MM) during pre-transplant period, day +30 and day +100 post cell infusion.

Results: 39 patients have been enrolled. Two patients (MEL=1, BEAM=1) received dose adjusted MEL or BEAM for renal dysfunction. Neutrophil engraftment day occurred a median 12.5 days after ASCT in MEL cohort and 11 in BEAM cohort. Platelet engraftment occurred at a median 15 days in MEL cohort and 14 days in BEAM patients. Neutrophil count nadir occurred sooner in the BEAM cohort. Neutropenic fever was observed in 14 (70%) of MEL patients and 17 (89%) of those who received BEAM. The number of infections by day 30 was 6/20 (30%) and was 5/19 (26%) in MEL and BEAM patients, respectively. ASCT infusion was given as outpatient setting for 16/20 (80%) in MEL and 8/19 (42%) in BEAM. 8 BEAM patients (47%) were discharged after preparative regime and received stem cells in outpatient setting. PFS at 3 years post-transplant was 53% in the Melphalan arm and 74% in the BEAM arm. At time of data cut-off, overall survival was 70% in the MEL arm and 94% in the BEAM arm. In the MEL arm, 1 patient developed ALL and 1 patient died from alternate causes. Quality of life measurements through well-validated scoring systems were similar in both arms.

Conclusions: The results signal that both regimens lead to similar rates of engraftment, unplanned hospitalizations, and non-hematologic adverse events. There appears to be a trend towards higher PFS in patients who receive BEAM. Therefore, we aim to complete enrollment by including 40 patients on each arm of the study for the results to achieve statistical significance. High dose chemotherapy can be safe, effective, and more financially feasible for patients worldwide compared to novel immunotherapies not yet available.