Achieving epidemiologically representative enrollment and social determinants of health in the phase III evERA Breast Cancer study (NCT05306340).

1572 Background: Clinical trials have historically under-enrolled patients (pts) from racial and ethnic minority groups, resulting in study populations that do not reflect the epidemiology of cancer in the United States (US), limiting generalizability of the findings. In parallel, social determinants of health (SDOH) are increasingly recognized as key drivers of cancer outcomes, yet are infrequently collected in oncology trials due to operational, ethical, and privacy concerns. The Phase III evERA breast cancer (BC) study (Mayer et al ESMO 2025) was intentionally designed to address both challenges through proactive enrollment strategies and prospective SDOH data collection. Methods: evERA BC is a global study in pts with ER+, HER2– advanced BC. In the US, a multi-pronged operational strategy was implemented to achieve epidemiologically representative enrollment, including expanded and pragmatic eligibility criteria, prioritization of community-based sites, real-time enrollment monitoring, patient navigation and financial support, and advocacy partnerships. A tailored survey assessing 5 key social determinants of health (education, income, employment status, marital status, insurance type) was offered to US pts to support a protocol-specified exploratory SDOH efficacy objective. Results: The multifaceted operational enrollment strategy used in the evERA BC study resulted in a US cohort (n=144 of total accrual 373) whose racial and ethnic composition exceeded SEER epidemiologic distributions for ER+, HER2− advanced BC for African American (AA) (12.5% vs 11.1%), Asian (9% vs 5.7%), and Hispanic (H) pts of any race (16% vs 8.9%). Enrollment for the aggregate White race (71.5%) and non-Hispanic (NH) ethnicity (83.3%) categories were slightly lower than SEER estimates for White race (82.9%) and NH ethnicity (91.1%). These enrollment patterns contrast with historic Phase III BC trials, in which AA pts typically comprise <5% and H pts <9% of enrolled populations. Of the 144 U.S. evERA BC pts, 128 (89%) completed the optional SDOH survey, demonstrating feasibility of SDOH data collection in a clinical trial setting and informing evaluation of potential trends and associations with outcomes. Conclusions: The evERA study demonstrates that key operational strategies can achieve epidemiologically representative enrollment while enabling robust and compliant SDOH data collection in oncology clinical trials. These findings provide a practical roadmap for industry sponsors seeking to improve recruitment of underrepresented populations and to generate more clinically meaningful and generalizable evidence by integrating social context into trial design and data interpretation. Clinical trial information: NCT05306340 .