Triple-Negative Breast Cancer: Can Adding Atezolizumab to Chemotherapy Improve Survival?

By: Jenna Carter, PhD
Posted: Thursday, August 22, 2024

An article published in the Annals of Oncology highlighted findings from the phase III IMpassion132 trial, which investigated the effects of adding atezolizumab to chemotherapy on overall survival in patients with early relapsing triple-negative breast cancer. Rebecca A. Dent, MD, MSc, FRCP, of the National Cancer Center Singapore, and colleagues reported that following administration of atezolizumab, 68% of patients had a disease-free interval of more than 6 months. However, overall survival was not improved by adding the PD-L1 inhibitor to chemotherapy in these patients. These findings were simultaneously presented at the European Society for Medical Oncology (ESMO) Breast Cancer 2024 Congress in Berlin.

“A biology-based definition of intrinsic resistance to immunotherapy in triple-negative breast cancer is urgently needed to develop novel therapies for these patients in next-generation clinical trials,” the investigators commented.

A total of 354 patients with rapidly relapsing PD-L1–positive triple-negative breast cancer were included in this study. Patients were enrolled more than 12 months after their last chemotherapy dose (anthracycline and taxane required) or surgery. Patients were then randomly assigned on a 1:1 basis to placebo or atezolizumab at 1,200 mg every 21 days with investigator-selected chemotherapy until disease progression or unacceptable toxicity.

Findings revealed that 68% of patients had a disease-free interval of more than 6 months. The overall survival hazard ratio was 0.93 (95% confidence interval = 0.73–1.20, P = .59; median 11.2 months with placebo vs 12.1 months with atezolizumab). Additionally, the median progression-free survival was 4 months across treatment arms and populations. The objective response rate was 28% with placebo vs 40% with atezolizumab. Safety analyses revealed that adverse events (predominantly hematologic) were similar between arms.

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

Annals of Oncology

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