A. Ramamoorthy, J. Bull, L. Zhang, M. A. Pacanowski; The US Food and Drug Administration, Silver Spring, MD

BACKGROUND: The frequency of genetic factors that influence treatment responses may vary based on race, e.g., EGFR mutations in non-small cell lung cancer (NSCLC) and interferon-responsive IL28B genotypes in chronic hepatitis C (CHC) are more common in Asians. We evaluated clinical trial enrollment patterns for drug development programs that may be sensitive to racial composition because genetic factors drive treatment decisions or responses to standard therapy.
METHODS: Descriptive analyses were performed to identify trends in racial composition of pivotal and supportive trials for 6 new FDA-approved (2008-2013) drugs for NSCLC and CHC.
RESULTS: In 23 trials, 11,324 patients were enrolled (Figure 1). For NSCLC, trials targeting EGFR mutated tumors enrolled more Asians (54%) than trials for ALK+ tumors (25%). For CHC, Asians were under-represented (2%), irrespective of interferon use. Blacks were under-represented in NSCLC (1%) and CHC (10%) relative to US prevalence.
CONCLUSION: Genetic factors that influence treatment response should be considered when interpreting trials because of potential effects on trial enrollment patterns. Targeted enrichment of responders, as for EGFR-mutations, may improve trial sensitivity and ease enrollment without affecting generalizability to the to-be-indicated population.