Can Immune Checkpoint Inhibitors Improve Pathologic Complete Response in Breast Cancer?

By: Vanessa A. Carter, BS
Posted: Thursday, May 12, 2022

In the NeoTRIP randomized study, Luca Gianni, MD, of Fondazione Michelangelo, Milan, and colleagues aimed to identify whether the addition of anti–PD-L1 therapy to chemotherapy could improve treatment efficacy in breast cancer. This study, which evaluated pathologic complete response, concluded that the addition of atezolizumab did not significantly increase the rate of response in patients with triple-negative breast cancer. Although follow-up is ongoing, the results of this trial were published in the Annals of Oncology.

“[This] report from the NeoTRIP first analysis is a contribution to the ongoing understanding of the immune checkpoint inhibitor use in triple-negative breast cancer,” mentioned the study authors in a European Society for Medical Oncology press release. “It underscores the need for dependable predictors of activity and efficacy of immune checkpoint inhibitors.”

This multicenter study enrolled 280 patients with triple-negative breast cancer who were randomly assigned to receive neoadjuvant carboplatin and nab-paclitaxel with (n = 138) or without (n = 142) atezolizumab. Treatment regimens were administered every 3 weeks for eight cycles prior to surgery, followed by four cycles of an adjuvant anthracycline regimen.

The intent-to-treat analysis demonstrated that the rate of pathologic complete response with atezolizumab was not statistically significant when compared with the rate without it (48.6% vs. 44.4%; odds ratio [OR] = 1.18). In women with high-risk, early-stage, triple-negative breast cancer, the addition of anti–PD-L1 therapy induced a 4.2% increase in pathologic complete response, and those with PD-L1–positive tumors experienced an increase of 7.6%. Notably, the presence of PD-L1 expression appeared to be the most significant factor influencing the rate of response (OR = 2.08).

As expected from previous experiences with atezolizumab, its use was associated with immune side effects. Nearly all patients given atezolizumab (98%) and chemotherapy alone (99%) had at least one treatment-related adverse event, with those on the former regimen experiencing a higher incidence of serious adverse events (P = .001) and abnormal liver transaminase (P = .003).

Disclosure: For full disclosures of the study authors, visit annalsofoncology.org.

Annals of Oncology