Abstract B050: Effectiveness of biologic agents among Hispanic patients with metastatic colorectal cancer

Abstract

Abstract Background: Randomized clinical trials have demonstrated the survival benefit provided by the addition of biologic drugs to chemotherapy (biochemotherapy) inpatients with metastatic colorectal cancer (mCRC). However, Hispanic patients are underrepresented in trial populations with limited data on treatment efficacy in them. We aim to ascertain effectiveness of biochemotherapy among Hispanic population in the US with mCRC using a comparitive effectiveness approach. Methods: This study includes two cohorts of patients: (a) age > 65 years mCRCdiagnosed from 2004 to 2011 who had received at least 1 dose of chemotherapyand had complete Medicare claims data using the Surveillance, Epidemiology, andEnd Result (SEER)–Medicare linked database, and (b) local Hispanic population from two hospitals in Bronx, New York, from 2006- 2020. Patient data were classified according to whether they received chemotherapy (oxaliplatin, irinotecan,and 5-fluorouracil or capecitabine) or biochemotherapy (bevacizumab, cetuximab,panitumumab, ramucirumab, or aflibercept, started within 3 months ofchemotherapy). Overall survival (OS) was defined as the time from starting chemotherapy to death or last follow-up. A weighted Cox regression model was used to assess differences in survival. Results: A total of 182 patients with mCRC were identified. Fifty one (28%) received chemotherapy and 131 (72%) received biochemotherapy. Median age was 69 and 68 years, respectively. There were no differences based on median income, marital status, primary site or sidedness, tumor differentiation grades or Charlson Comorbidity Score between both groups. Among patients who received only chemotherapy, 9% received second or greater lines of chemotherapy when compared to 51% in the biochemotherapy group (p < 0.001). The median overall survival was 11.3 (95% CI:6.3 - 19.4) months (mo) and 17 ( 95% CI: 13.0 -25.8) mo, respectively. Biochemotherapy conferred an OS benefit of 39% with average HR = 0.61 (0.40-0.94; p = 0.047). This was 45% in the first two years (HR 0.55). Beyond 2 years, there was an apparent reversal with HR 1.7, suggesting 70% deteriment in OS. Conclusions: In this comparative effectiveness study of a cohort of Medicare recipients and the Bronx population, with mCRC, biochemotherapy was associated with an improvement in OS, especially in the first 2 years. Disclosure: Funded by R21: 1R21AG058027-01 to Sanjay Goel and Abdissa Negassa Citation Format: Riya Patel, Abdissa Negassa, Seda Tolu, Ana Acuna-Villaorduna, Sanjay Goel. Effectiveness of biologic agents among Hispanic patients with metastatic colorectal cancer [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B050.