Limited inclusion in clinical trials and access to poly (ADP-ribose) polymerase inhibitors in racial and ethnic minority patients with cancer: a narrative review

BACKGROUND: Poly ADP-ribose polymerase (PARP) inhibitors (PARPi) have revolutionized cancer care across multiple solid tumor types for patients with BRCA mutations and homologous recombination deficient malignancies. Sentinel trials for PARPi, however, have had limited participation from non-European populations, limiting interpretation of results, dosing strategies, and quality-of-life implications in these patients. Our objective was to review participation by race and ethnicity in sentinel PARPi trials across disease sites. METHODS: A literature search was conducted using PubMed/MEDLINE. Core search terms included "PARP inhibitor" and the disease sites of interest (breast, ovary, prostate, and pancreas). A review of each sentinel trial was conducted utilizing data from ClinicalTrials.gov to obtain and/or confirm demographic information. RESULTS: Sentinel PARPi trials across all disease sites included populations that were predominantly White. TRITON2 (prostate) had the highest proportion of Black participants (5.8%), while Black participation in breast and ovarian cancer trials was almost always <3%. Missing data on race and ethnicity was common, and highest in TRITON2 and TRITON3 (∼20%, prostate) and ARIEL3 (13.3%, ovary). Aggregation into an "other" category was highest in EMBRACA (17.2%). Hispanic ethnicity was reported in only 5 of the 14 trials. CONCLUSION: There is overwhelming underrepresentation of racial and ethnic minorities in sentinel PARPi trials. Systemic issues in accepted clinical trial infrastructure, including reporting practices, site selection, protocol biases, and access challenges are all likely etiologies. Addressing the complexity of inclusion in global oncology research is still a crucial need to ensure cancer care equity.