Differences in disease characteristics and outcomes in older versus younger adults with multiple myeloma.

Abstract

e20041 Background: Older adults are underrepresented in clinical trials in multiple myeloma (MM), as are the risk prognostication schema derived from them, which limits their generalizability to this age group. Despite appropriate fitness, older adults may not be offered the same therapies as their younger counterparts. In this study, we compared disease characteristics and their associations with outcomes in older and younger adults with MM. Methods: We obtained data for newly diagnosed MM patients from the MM Research Foundation CoMMpass registry (version IA16), a prospective observational study with highly annotated clinical data, cytogenetics, and longitudinal outcomes. Chi-square or Fisher’s exact test were used for comparisons of categorical variables. Progression free survival (PFS) and overall survival (OS) curves were constructed using the Kaplan–Meier method and compared with the log-rank test. Cox proportional hazard models were computed to estimate hazard ratio (HR) and 95% confidence interval (CI) for association between pre-treatment variables and outcomes. Results: 1,143 patients were analyzed, including 853 patients (pts) under age 70 years (< SEV) and 290 pts age 70+ years (SEV+). SEV+ had a higher frequency of ISS score 3 (p < 0.001), lower estimated glomerular filtration rate (median 57.6 vs 74.7 mL/min/1.73m2, p < 0.001), and worse ECOG performance status (PS) (p = 0.01). Of the cytogenetic abnormalities analyzed [del17p, gain1q, t(4;14), t(8;14), t(14;16), t(14;20), and hyperdiploidy], SEV+ had higher frequency of gain1q (42% vs 33%, p = 0.02) and t(14;20) (3% vs 1%, p = 0.03) compared with younger adults. SEV+ received less proteasome inhibitor + immunomodulatory imide triplet induction therapy (27% vs 55%, p < 0.001) and less frontline autologous stem cell transplant (ASCT) (22% vs 59%, p < 0.001). SEV+ were less likely to achieve >complete response to induction therapy compared to < SEV (32% vs 18%, p < 0.001). SEV+ had worse PFS (HR 1.8, 1.6-2.2, p < 0.001) and OS (2.3, 1.8-2.9, p < 0.001) compared to < SEV. On multivariate analysis, increasing ISS, gain1q, high risk gene expression profiling (UAMS70), and lack of triplet induction with frontline ASCT were associated with both poorer PFS and OS in < SEV. For SEV+, multivariate analysis revealed that increasing ISS, t(14;16), and lack of triplet+ASCT were associated with inferior PFS, while age, male sex and increasing ISS were associated with inferior OS. Conclusions: Older adults have a greater prevalence of ISS 3, gain1q, and t(14;20) compared with younger adults but only ISS translates into inferior PFS or OS within this group. Increased access to triplet induction therapy and expanding access to frontline ASCT among older adults may help to improve outcomes in this growing subset of patients.