Angela DeMichele, MD, MSCE, the Alan and Jill Miller Professor in Breast Cancer Excellence at the Perelman School of Medicine of the University of Pennsylvania in Philadelphia, commented on NIMBUS¹ for The ASCO Post.

She said obtaining information on tumor mutational burden is simple, as it is part of the genomic assay report most oncologists receive on their patients. It would behoove clinicians to take a closer look at what this information can mean to a subset of patients, she added.

Angela DeMichele, MD, MSCE

“We see that it’s very rare to have a patient with tumor mutational burden of 10 mut/Mb or higher, although in many other cancers, it can be common. I think that’s because much of breast cancer is an immune desert: the cells are not that damaged except in triple-negative breast cancer, where tumors cannot repair the damage,” she explained.

Researchers are just now beginning to define those subsets of patients who might benefit from the success of checkpoint inhibition in other cancers. In breast cancer, she said, “this may be a niche population.” However, considering the prevalence of breast cancer, “it’s not an insignificant number.”

“It’s important to identify these patients,” she said. “Finding them can be meaningful.”

DISCLOSURE: Dr. DeMichele has received institutional research funding from Calithera Biosciences, Genentech, Novartis, and Pfizer.

REFERENCE

1. Barroso-Sousa R, Li T, Reddy S, et al: Nimbus: A phase 2 trial of nivolumab plus ipilimumab for patients with hypermutated HER2-negative metastatic breast cancer. 2021 San Antonio Breast Cancer Symposium. Abstract GS2-10. Presented December 8, 2021.