Efficacy of Neoadjuvant Immunotherapy on Breast Cancer is Independent of Race

Black and non-Black patients who take durvalumab (Imfinzi) and chemotherapy before surgery have positive outcome for triple-negative breast cancer (TNBC), according to a phase 1/2 clinical trial published in Clinical Cancer Research.

Black patients continue to be underrepresented in investigational therapies and clinical trials, according to Lajos Pusztai, MD, DPhil, professor of medicine, and co-leader of the Genetics, Genomics, and Epigenetics Program;¹ however, they are the ones most affected by TNBC.^1,2

TNBC does not test positive for estrogen receptors, progesterone receptors, or the human epidermal growth factor receptor 2 (HER2) protein, which are indicators of other forms of breast cancer.²

TNBC makes up 10%-15% of all breast cancers, differing from other breast cancers because it grows and spreads faster, has less treatment options, and has a worse outcome.² It also tends to afflict women younger than 40 years of age.²

“The low accrual of ethnic minorities, particularly Black Americans, in clinical trials is problematic for several reasons,” Pusztai said in a press release. “For one, it means Black patients are not given equitable access to potentially lifesaving new treatments very early on. Secondly, it limits our ability to study potential differences in drug metabolism, toxicity, and efficacy between populations with different ancestries.”¹

The immunotherapeutic durvalumab targets the PD-1/PD-L1 immune checkpoint pathway. Other studies done by these study authors indicated that durvalumab benefited patients with non-metastatic TNBC when combined with chemotherapy and administered before surgery.¹

This study was limited, however, because the participants were not an accurate reflection of the racial or ethnic makeup of the disease population in the surrounding neighborhood, according to the authors.¹

Pusztai and colleagues decided to enter more patients into this original trial. This could help them understand the efficacy of durvalumab and chemotherapy (pre-surgery) on Black patients who make up the majority of TNBC patients.¹

The trial incorporated 67 new patients—21 people identified as Black,40 as non-Hispanic white patients, 3 as Hispanic/Latino, and 3 as Asian. The local community was better reflected with 31% of participants identifying as Black. Race did not differ across baseline tumor features.¹

The pathologic complete response (pCR) to neoadjuvant durvalumab and chemotherapy was not significantly different with race. Of the 31 patients who had a positive pCR and no sign of cancer, 43% of patients were Black and 48% were non-Black patients.¹

Rates of metastatic recurrence were also not significantly different between Black and non-Black patients, at 14% and 17%, respectively. Further, there were not significant differences observed in the 3-year overall survival (OS) Black and non-Black patients (81% and 87%, respectively) or 3-year event-free survival (71.4% and 78.3%, respectively).¹

Patients with a pCR had significantly longer event-free survival and OS in Black and non-Black patients. With a pCR, the 3-year OS rate was 96.8% and the event-free survival rate was 90.3%, compared to 81.8% and 66.7% for those without a pCR, respectively.¹ The study was limited by a small sample size and single institution location, according to the authors.¹

“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,” Pusztai said. “By improving health care access and delivery, we could mitigate some of the health care disparities that exist in our society.”¹

Reference

Benefits of pre-surgical immunotherapy were independent of race in patients with aggressive breast cancer. EurekAlert! July 29, 2022. Accessed on July 29, 2022. https://www.eurekalert.org/news-releases/960058