Age no bar: A CIBMTR analysis of elderly patients undergoing autologous hematopoietic cell transplantation for multiple myeloma

Background: Upfront autologous hematopoietic stem cell transplantation (AHCT) remains an important therapy in the management of patients with multiple myeloma (MM), a disease of older adults. Methods: The authors investigated the outcomes of AHCT in patients with MM who were aged ≥70 years. The Center for International Blood and Marrow Transplant Research (CIBMTR) database registered 15,999 patients with MM in the United States within 12 months of diagnosis during 2013 through 2017; a total of 2092 patients were aged ≥70 years. Nonrecurrence mortality (NRM), disease recurrence and/or progression (relapse; REL), progression-free survival (PFS), and overall survival (OS) were modeled using Cox proportional hazards models with age at transplantation as the main effect. Because of the large sample size, a P value <.01 was considered to be statistically significant a priori. Results: An increase in AHCT was noted in 2017 (28%) compared with 2013 (15%) among patients aged ≥70 years. Although approximately 82% of patients received melphalan (Mel) at a dose of 200 mg/m² overall, 58% of the patients aged ≥70 years received Mel at a dose of 140 mg/m². On multivariate analysis, patients aged ≥70 years demonstrated no difference with regard to NRM (hazard ratio [HR] 1.3; 99% confidence interval [99% CI], 1-1.7 [P =.06]), REL (HR, 1.03; 99% CI, 0.9-1.1 [P = 0.6]), PFS (HR, 1.06; 99% CI, 1-1.2 [P = 0.2]), and OS (HR, 1.2; 99% CI, 1-1.4 [P =.02]) compared with the reference group (those aged 60-69 years). In patients aged ≥70 years, Mel administered at a dose of 140 mg/m² was found to be associated with worse outcomes compared with Mel administered at a dose of 200 mg/m², including day 100 NRM (1% [95% CI, 1%-2%] vs 0% [95% CI, 0%-1%]; P =.003]), 2-year PFS (64% [95% CI, 60%-67%] vs 69% [95% CI, 66%-73%]; P =.003), and 2-year OS (85% [95% CI, 82%-87%] vs 89% [95% CI, 86%-91%]; P =.01]), likely representing frailty. Conclusions: The results of the current study demonstrated that AHCT remains an effective consolidation therapy among patients with MM across all age groups.