Abstract 3669: Racial/ethnic disparities in treatment with bone-modifying agents among newly diagnosed multiple myeloma patients
Authors: Guadamuz Jenny S. , Rohrer Rebecca , Mohyuddin Ghulam Rehman , Chiu Brian C.-H. , Patel Pritesh R. , Sweiss Karen , Seymour Erlene , Sborov Douglas , Calip Gregory S. 
Published: June 2022

Abstract
Introduction: There are racial/ethnic disparities in multiple myeloma (MM) treatment, including differences in the use of novel agents, stem cell transplantation, and supportive therapies such as bone-modifying agents (BMAs). BMAs reduce the frequency of fractures and skeletal-related pain, and some evidence suggests that more recently approved agents (i.e., denosumab) confer greater progression-free survival benefits than older agents (i.e., bisphosphonates). Here we describe disparities in the initiation of BMA use and uptake of denosumab among newly diagnosed MM patients by race/ethnicity.
Methods: We conducted a retrospective cohort study using the nationwide Flatiron Health electronic health record-derived de-identified database. This analysis included adults (≥ 18 years) newly diagnosed with MM between January 2018 and September 2021 who initiated first-line therapy. Patient demographics and clinical characteristics were determined using structured and unstructured data, curated via technology-enabled abstraction. Cumulative incidence functions accounting for competing risks were used to estimate the initiation of BMA use within 90 days before the start of first-line MM therapy and 30 days post. We used multivariable logistic regression models to estimate odds ratios (OR) and 95% confidence intervals (CI) for differences in the receipt of denosumab versus bisphosphonates alone (zoledronic acid or pamidronate) among patients who initiated BMA use.
Results: Among 4460 newly diagnosed MM patients, 52% were White, 17% were Black, 7% were Latinx, and 2% were Asian. Overall, 2208 (50%) initiated BMA treatment, and utilization differed across racial/ethnic groups with higher rates observed among Asian (55%), White (51%), and Latinx (50%) patients compared to Black patients (44%) (P=0.023). Among patients that initiated BMAs, 53% received denosumab and 47% received bisphosphonates alone. Compared to White patients, Black (OR 1.06, 95% CI 0.83-1.36) and Asian (OR 0.82, 95% CI 0.44-1.53) patients had similar odds of receiving denosumab, whereas Latinx patients had significantly lower odds of receiving denosumab (OR 0.56, 95% CI 0.40-0.79).
Conclusion: Among newly diagnosed MM patients, approximately half initiated BMAs. Substantial racial/ethnic disparities exist. For example, Black patients were less likely to receive any BMAs, and, even when treated, Latinx patients were less likely to receive denosumab. Future research should determine whether these treatment disparities impact progression-free and overall survival in real-world MM data.
Citation Format: Jenny S. Guadamuz, Rebecca Rohrer, Ghulam Rehman Mohyuddin, Brian C.-H. Chiu, Pritesh R. Patel, Karen Sweiss, Erlene Seymour, Douglas Sborov, Gregory S. Calip. Racial/ethnic disparities in treatment with bone-modifying agents among newly diagnosed multiple myeloma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3669.