Minority racial groups continue to be dismally represented in cancer trials — study
Data reveal that different racial and ethnic groups — by nature and/or nurture — can respond differently in terms of pharmacokinetics, efficacy, or safety to therapeutics, but this disparity is not necessarily accounted for in clinical trials. A fresh analysis of the last decade of US cancer drug approvals suggests the trend continues, cementing previous research that suggests oncology trials are woefully under-representative of the racial makeup of the real world.
The study, published in the journal JAMA Oncology, evaluated 230 trials to see whether sponsors reported the racial composition of the patients enrolled in their studies, and how minorities were represented (versus their actual population prevalence) in clinical trials that led to cancer drug approvals from 2008 to 2018.
Researchers from the University of British Columbia, the University of Texas MD Anderson Cancer Center, the Fred Hutchinson Cancer Center in Seattle and Baylor University found that 145 (63%) disclosed at least one race — but a meager 18 (7.8%) documented the four major races: White, Asian, Black and Hispanic.
Compared to the actual makeup of US cancer patients — Blacks (22% of expected) and Hispanics (44% of expected) were underrepresented compared with Whites (98% of expected) and Asians (438% of expected), the analysis found.
This pattern is consistent — even though the NIH requires that minority populations be appropriately represented in clinical research. Corporations, which carry the lion’s share of drugs across the finish line, are only recommended to shore up representation by the FDA.
A study exploring the reasons behind chronic underrepresentation of minorities in oncology trials, published in 2016, cited a systematic review of late-stage cancer trials from 1990 to 2000 and 2001 to 2010 showed that ethnic minorities, particularly African-Americans, were not adequately represented.
In studies conducted between 2001 and 2010 that reported race/ethnicity, reviewers found that 82.9% of participants were White, 6.2% were African American, 3.3% were Asian, 2.2% were Hispanic, and 0.1% were Native American. In trials conducted between 1990 and 2000, 89% of participants were White, 10.5% were African American, 0.4% were Hispanic, and 0.04% were Asian. Even though the proportion of White participants decreased across the two periods, Whites continued to comprise a large majority of participants, and the proportion of African American participants decreased between the periods 1990 to 2000 and 2001 to 2010, the researchers extrapolated. Low minority representation results from “preventable and interlinked policies, practices, and barriers at the system, individual, and interpersonal levels,” they concluded.
The pattern of disproportionate enrollment in trials testing treatments for cancer — a disease which there are pronounced racial and ethnic disparities in incidence and mortality — is especially concerning given the new wave of checkpoint inhibitors.
In a separate study published this May, researchers found that Black patients constituted less than 4% of patients recruited across multiple trials that supported the approval of immune checkpoint inhibitors for lung cancer. The discrepancy was echoed in trials conducted in renal cell carcinoma and other tumor types.
“The inadequate representation of minority patients on immunotherapy clinical trials could perpetuate outcome disparity because the unique biology of the host and the tumors from this subpopulation is not accounted for as new treatment algorithms to guide optimal use of immunotherapy are developed for use in the real world,” the researchers suggested.