A study of U.S. adolescent and young adult patients with acute lymphoblastic leukemia (ALL) found that Hispanic patients were significantly underrepresented in a large clinical trial compared with the general patient population. The study, presented by Muffly et al at the 2021 American Society of Hematology (ASH) Annual Meeting & Exposition (Abstract 337), also found that Hispanic patients in the trial had leukemia outcomes on par with non-Hispanic White participants, suggesting that clinical trial participation can help to mitigate some of the racial and ethnic disparities in cancer outcomes observed in the overall population, further underscoring the need to ensure appropriate racial diversity in cancer clinical trials.

“It is an ongoing problem in cancer research that we repeatedly see a significant mismatch between clinical trial participants and what is happening in the real world,” said first study author Lori Muffly, MD, MS, of Stanford University School of Medicine. “We have to do more to align our clinical trial participants with the epidemiology of disease across this country.”

CALGB 10403

The researchers analyzed health outcomes, socioeconomic status, and race and ethnicity among 295 AYA patients with ALL enrolled in CALGB 10403, a clinical trial evaluating a treatment regimen designed specifically for younger patients that was found to be superior to a regimen used for older patients. They then compared the CALGB data with data from cancer registries reflecting the overall incidence (the North American Association of Cancer Registries) and overall survival (SEER registry) of patients with ALL from different racial and ethnic groups in a similar age range.

The results showed a difference between clinical trial participants and the general population; while 41.7% of U.S. AYA patients with ALL were Hispanic, only 16.3% of CALGB 10403 participants were Hispanic. In part, this difference was explained by the fact that the study did not enroll patients in some states that have a high proportion of Hispanic residents, such as Texas and Florida. However, researchers found Hispanic participants were underrepresented in each state where the trial did open compared with the proportion of Hispanic patients in the broader population for that state.

The study also found that Hispanic patients who participated in CALGB 10403 had high rates of compliance with trial protocols and outcomes that were similar to those for non-Hispanic White participants, despite having a higher likelihood of genetic markers associated with worse ALL outcomes. This contrasts with SEER registry data that showed Hispanic patients in the general population have significantly worse outcomes than non-Hispanic White patients.

“For diseases that heavily affect certain racial or ethnic groups, putting thought into where those patients are located and where trials open could help,” said Dr. Muffly. “These findings should generate conversations about how we can do better.”

The researchers found different trends among Black patients, who comprised a much smaller proportion of patients in both CALGB 10403 and the broader AYA ALL population. The proportion of Black patients in the clinical trial (6.4%) was roughly the same as the proportion in the patient population broadly (8.5%), and Black patients saw significantly worse outcomes across the board, a finding researchers said warrants further investigation.

Disclosure: For full disclosures of the study authors, visit ash.confex.com.