Impact of race, ethnicity, and social determinants on outcomes following immune checkpoint therapy

Immune checkpoint blockade (ICB) therapies are one of the greatest advances in the history of cancer care and are now commonly used in the management of many different malignancies. However, much remains unknown about the factors that affect the efficacy and side effect profile of these agents. This review delves into the published literature that evaluates the intricate interplay between race, age, gender, and social determinants in shaping outcomes following ICB across solid tumors and hematologic malignancies. We examine the pivotal phase 2 and 3 trials to evaluate the demographics of participants and outcomes based on these variables, if reported. Most, but not all, trials reported some basic demographic information like age, sex, race, ethnicity, and/or geographic area for enrollment. Clinically relevant biological markers that could affect ICB outcomes such as obesity or markers of social determinants of health were largely not reported. Trials were generally representative for men and women based on expected prevalence for a given malignancy, but often under-represented non-white participants and rarely enrolled patients from the global south. Subgroup analyses were conducted in many ICB trials for solid malignancies, but rarely conducted for hematologic malignancies. These analyses largely showed similar qualitative benefit across subgroups, but adverse events were rarely reported by subgroup. This review adds to our understanding of the populations that these clinical trials have studied and highlight the urgent need to redouble our efforts at increasing the diversity of the population in future ICB trials.