Racial differences in longitudinal toxicities of anticancer agents in early phase cancer clinical trials

Racial differences have been reported in toxicity outcomes for anticancer drug treatments. However, these observations were often from studies with small sample sizes, and many only reported the maximum grade of toxicity and no longitudinal information. This current analysis aims to investigate racial differences in longitudinal toxicities using a large-scale clinical trials database.

Early-phase clinical trials sponsored by the Cancer Therapy Evaluation Program at the National Cancer Institute, USA, that evaluated cytotoxic drugs and molecularly targeted agents between March 2000 and December 2012 were studied. Race was categorized as White, Black or African-American, and Asian. Each toxicity's grade prevalence, mean grade at each cycle, and time to develop grade 2 or higher toxicity was evaluated.

In total, 25,442 patients from 697 trials were included in this study. The number of patients categorized as White, Black, and Asian designations was 22,756 (89%), 1874 (7%), and 812 (3%), respectively. Notable findings include the rate of any grade of diarrhea in Black people was 26% and 21% lower than that of White and Asian people. The median time to the first grade 2 or higher event was 6 cycles in White people, 8 in Black people, and 6 in Asian people. The rate of any grade hyperglycemia was significantly higher in Asian people.

Although we identified several racial differences in longitudinal toxicities, most were of generally lower grade. Further study is needed to clarify the cause of racial differences in treatment-associated toxicities.