Cancer Immunotherapy Trial Shows Similar Results Regardless of Race

Clinical outcomes are similar between Black and non-Black patients when patients receive identical treatment and follow-up in a highly structured study environment, researchers say. 

When Black patients were included in proportion to the larger community in a clinical trial of a new therapy for patients with triple-negative breast cancer (TNBC), outcomes were much the same across racial groups, results published in Clinical Cancer Research, a journal of the American Association for Cancer Research, found.

“Our study demonstrates that if patients are given similar treatment and similar follow-up, the differences in outcomes between Black and non-Black patients are reduced,” said Lajos Pusztai, MD, DPhil, a professor of medicine and the director of breast cancer translational research at the Yale School of Medicine. “By improving health care access and delivery, we could mitigate some of the health care disparities that exist in our society.”

The trial was a test of an immunotherapy “checkpoint inhibitor” called durvalumab (Imfinzi), plus chemotherapy, given for several months before surgery for TNBC, an approach called neoadjuvant treatment. A trial conducted by Dr. Pusztai and colleagues showed that the treatment was beneficial to patients. However, the initial study population didn’t include enough Black participants to reflect either the racial and ethnic makeup of the neighborhood surrounding the Yale Cancer Center in New Haven, Connecticut, or the overall population affected by TNBC, Dr. Pusztai said.

“The low accrual of ethnic minorities, particularly Black Americans, in clinical trials is problematic for several reasons,” he said. “For one, it means Black patients are not given equitable access to potentially life-saving new treatments. Secondly, it limits our ability to study potential differences in drug metabolism, toxicity, and efficacy between populations with different ancestries.”

To address the lack of diversity in the initial trial population, Dr. Pusztai and colleagues opened the trial for additional Black patients. The final trial population after the expanded accrual included 67 patients, of whom 21 (31 percent) identified as Black, bringing the proportion of Black patients closer to that of the local community. Forty patients identified as non-Hispanic white, three as Hispanic/Latino, and three as Asian. Patient characteristics and baseline tumor features did not differ dramatically by race.

Among the 67 patients enrolled in the trial, 31 (46 percent) had a pathologic complete response (pCR) to neoadjuvant durvalumab plus chemotherapy, meaning that there were no signs of cancer in their breast tissue after treatment. There were no statistically significant differences by race: 43 percent of Black patients had a pCR compared with 48 percent of non-Black patients. 

Similarly, no statistically significant differences were observed between Black and non-Black patients for the rates of metastatic recurrence (14 percent vs 17 percent), three-year overall survival (81 percent vs 87 percent), and three-year event-free survival (71.4 percent vs 78.3 percent). 

In both the Black and non-Black cohorts, patients who had a pCR had significantly longer event-free survival and overall survival than those who did not have a pCR. Three-year overall survival rates were 96.8 percent for patients with a pCR and 81.8 percent for those without. Three-year event-free survival rates were 90.3 percent and 66.7 percent among those with a pCR and those without, respectively.

“These results suggest that clinical outcomes are similar regardless of race when patients receive identical treatment and follow up in a highly structured study environment,” Dr. Pusztai observed. “A deliberate effort to increase participation by underrepresented minority patients in clinical trials will not only improve our understanding of the efficacy and safety of these drugs in diverse patient populations but also ensures more equal access to novel therapies.”

Limitations of the study include the small sample size and the participation of only one institution, Yale Cancer Center.