Increased trial participation may mitigate survival disparities for Hispanic AYAs with ALL
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Hispanic individuals appeared considerably underrepresented in a large clinical trial of adolescents and young adults with acute lymphoblastic leukemia, according to study results presented at ASH Annual Meeting and Exposition.
However, Hispanic trial participants achieved outcomes comparable to those of non-Hispanic white participants.
This finding suggests clinical trial participation may help mitigate racial and ethnic disparities in cancer survival observed in the overall population, according to Lori Muffly, MD, MS, associate professor of medicine at Stanford University School of Medicine.
“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,” Muffly said in a press release. “We have to do more to align our clinical trial participants with the epidemiology of disease across this country.”
The adolescent and young adult (AYA) population in cancer care is defined as those aged 15 to 39 years.
About 40% of AYAs with ALL in the United States are Hispanic and 7% are Black, according to SEER data. Population-based data show outcomes for these groups are significantly inferior to those of non-Hispanic whites.
Muffly and colleagues examined enrollment patterns of Hispanic and Black patients on CALGB 10403, a prospective phase 2 trial that demonstrated superiority of a pediatric-inspired ALL regimen vs. historical adult regimens for AYAs with newly diagnosed ALL.
Investigators used North American Association of Central Cancer Registries (NAACCR) data to compare trial enrollment by race/ethnicity with incidence nationwide. They used SEER data to compare survival outcomes of trial participants with national data.
The analysis included 295 AYAs from 31 states enrolled on CALGB 10403 between 2007 and 2012, and 263 patients reported ethnicity.
CALGB 10403 included a significantly lower proportion of Hispanic individuals compared with the AYA population of patients with ALL nationwide (16.3% vs. 41.7%; P < .001). The distribution of Black individuals between the trial and national population appeared similar (6.4% vs. 8.5%).
Black AYAs appeared more likely to have T-cell ALL, whereas Hispanic AYAs appeared more likely to have Philadelphia chromosome-like B-cell ALL and CRLF2 rearrangements. Researchers reported no significant differences in age, sex, cytogenetics or BMI by race or ethnicity among trial enrollees.
Muffly and colleagues explored reasons for disproportionately low Hispanic enrollment on CALGB 10403.
NAACCR data identified seven states with the highest proportion of Hispanic patients with ALL — California, Texas, New Mexico, Arizona, Colorado, Florida and New Jersey. Only 47 (15.9%) of the 295 AYAs enrolled in CALGB 10403 came from those seven states. The trial did not open in Texas or Florida.
“For diseases that heavily affect certain racial or ethnic groups, putting thought into where those patients are located and where trials open could help,” Muffly said. “These findings should generate conversations about how we can do better.”
In states where the trial did open, Hispanic AYAs were significantly under-enrolled compared with population incidence, Muffly said. For example, 34% of patients from California who enrolled in the trial reported Hispanic ethnicity; however, 65% of AYA patients with ALL in the state are Hispanic.
“Geographical alignment may be low-hanging fruit, but improving enrollment of Hispanic and other ethnic and racially diverse groups is a complex issue that requires a multipronged approach,” Muffly said during a press conference.
An examination of outcomes across the CALGB 10403 cohort showed 3-year EFS of 59.1% (95% CI, 53.1-65.75) and 3-year OS of 73.5% (95% CI, 68.1-79.4).
Researchers reported a higher rate of per-protocol therapy completion among Hispanic patients (75%) than Black patients (64%) or non-Hispanic white patients (56%; P = .049).
In CALGB 10403, Hispanic patients achieved 3-year OS comparable to non-Hispanic white patients (75% vs. 74%), whereas Black patients achieved a lower 3-year OS rate (58%). These results contradict SEER estimates, which show both Hispanic and Black patients achieve poorer OS compared with non-Hispanic white patients.
“This in-depth analysis of racial/ethnic enrollments and outcomes on CALGB 10403 uncovered findings that may translate across clinical trials beyond AYA ALL,” Muffly and colleagues wrote. “Relative to non-Hispanic [white patients], Hispanic patients had superior survival despite having higher rates of Ph-like ALL, indicating that clinical trial participation may mitigate racial/ethnic survival disparities seen in population-based data.
“Finally, we saw no improvement in trial outcomes among Black AYAs,” researchers added. “A deeper understanding of the biological leukemia underpinnings and barriers to successful outcomes would aid future efforts at improving survival across racial/ethnic groups.”
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Martin S. Tallman, MD
This abstract addresses the important area of disparities in health care. In addition to disparities in outcomes, there also are disparities simply related to enrollment in clinical trials. Forty percent of AYAs with ALL in the United States are Hispanic and 7% are Black. Both have inferior outcomes compared with white patients. This study demonstrated that fewer Hispanic patients were enrolled on a major clinical trial than are represented in the U.S. population. This is not entirely surprising, given the trial was not available in a number of states that have the highest population of Hispanic patients. Interestingly, survival was superior among Hispanic patients, many of whom had a poor prognosis. Conducting clinical trials in geographic areas that reflect disease incidence likely will improve minority enrollment. Further, what is even more intriguing is that patients with a poor prognosis appeared to fare better by participating on a clinical trial.
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Muffly L, et al. Abstract 337. Presented at: ASH Annual Meeting and Exposition; Dec. 11-14, 2021; Atlanta.
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