Limited feasibility of double transplant in multiple myeloma: Results of a multicenter study on 153 patients aged <65 years

BACKGROUND. Although high-dose therapy is considered the standard therapy for younger patients with multiple myeloma (MM), the advantages of performing a second transplant remain debated. The current study was conducted to evaluate the efficacy and the feasibility of a front-line double transplant program in young MM patients. METHODS. A total of 153 MM patients aged ≤65 years, the majority of whom had stage III disease (65%), were enrolled in a multicenter, nonrandomized, high-dose program including 2 transplants. RESULTS. The percentage of good quality responses (complete and very good partial responses) increased from an initial 33% after induction to 91% (complete response rate of 29%) after 2 transplants. However, this increase in response did not produce an advantage in either event-free survival or overall survival, even when the analysis was performed grouping patients by response. The protocol was well tolerated and no difference in transplant-related mortality was observed between the first and second transplants. A first transplant was performed in 122 of 153 patients (80%), and 65 (42% of the enrolled patients) completed the double transplant program. Reasons for not undergoing the second autologous transplant were death (n = 2 patients), insufficient peripheral blood stem cells (n = 8 patients), severe transplant-related toxicity (n = 10 patients), allotransplants (n = 9 patients), early progression after first transplant (n = 6 patients), lost to follow-up (n = 3 patients), and patient refusal (n = 19 patients). CONCLUSIONS. Considering the limited advantage of double transplants, the complexity of the program, the high percentage of dropouts, and the additional costs of a second transplant, the current study favors single transplant programs for the treatment of younger MM patients.