Comparative Effectiveness of Biologic Agents Among Black and White Medicare Patients in the US With Metastatic Colorectal Cancer

Abstract

Randomized clinical trials have defined the survival benefit provided by the addition of biologic drugs to chemotherapy in patients with metastatic colorectal cancer (mCRC). However, Black patients may be underrepresented in trial populations, and outcomes in this group remain poorly defined. To determine whether the real-world benefit of biologic drugs in Black patients is consistent with the real-world benefit of biologic drugs in White patients using a comparative effectiveness research approach. Population-based retrospective comparative effectiveness analysis of a cohort of patients aged 65 years or older with mCRC diagnosed between 2004 and 2011 who had received at least 1 dose of chemotherapy and had complete Medicare claims data using the Surveillance, Epidemiology, and End Result (SEER)-Medicare linked database. Data were analyzed from August 1, 2020, to March 31, 2021. Patient data were classified according to whether patients received chemotherapy (oxaliplatin, irinotecan, and 5-fluorouracil or capecitabine) or biochemotherapy (bevacizumab, cetuximab, panitumumab, ramucirumab, or aflibercept, started within 3 months of chemotherapy). Overall survival (OS) 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. A total of 5617 patients with mCRC were identified in the SEER-Medicare linked database, and 4542 patients were included in the main analysis. Of the 5617 patients, 3969 (70.7%) received biologic agents at any point between 2004 and 2011; biologic agent therapy was started within 3 months of chemotherapy in 2894 patients (72.9%). Among 4542 patients with data on race and ethnicity, the median age was 72 years (IQR, 68-78 years), 2365 (52.0%) were female, 3445 (75.8%) had colon as the primary site, 552 (12.2%) were Black patients, and 3990 (87.8%) were White patients. There was no difference in the receipt of 1 (76.7% and 74.8%) vs 2 or more (23.3% and 25.2%: P = .92) lines of therapy, and in the receipt of biologic agents (63.6% vs 64.3% P = .33), among White patients and Black patients, respectively. Biochemotherapy was associated with a significant survival benefit compared with chemotherapy alone in the overall population (biochemotherapy median OS, 17.9 [95% CI, 17.3-18.7] months vs chemotherapy median OS, 8.3 [95% CI, 9.1-9.9] months; P < .001). The survival benefit was similar among White patients (17.8 vs 9 months; average hazard ratio, 0.59; 95% CI, 0.55-0.64; P < .001) and Black patients (18.6 vs 9.9; average hazard ratio, 0.58; 95% CI, 0.47-0.71; P < .001). In this comparative effectiveness analysis of a cohort of Medicare recipients with mCRC, biochemotherapy was associated with an improvement in OS with a similar rate of reduction in mortality among Black and White patients. Clinicians may offer biochemotherapy therapy to all patients to maximize clinical benefit, factoring in clinical variables, but not their race.