Cemiplimab and fianlimab with neoadjuvant chemotherapy in early-stage high-risk -negative breast cancer

About the Study: Is combined inhibition of programmed cell death 1 protein (PD-1) and lymphocyte activation gene 3 (LAG-3) added to standard neoadjuvant chemotherapy (NAC) safe and effective in (formerly HER2)-negative early-stage breast cancer at high risk of recurrence? This phase 2 randomized clinical trial including 78 participants with -negative breast cancer found that combining cemiplimab and fianlimab with paclitaxel-based NAC improved rates of pathologic complete response in all participants, including those with triple-negative and hormone receptor−positive subtypes. Patients positive for the ImPrint immune signature were highly sensitive to the combination, providing a potential biomarker of treatment response. These results indicate that combined PD-1 and LAG-3 inhibition warrants further investigation in -negative breast cancer.

Corresponding Author: Claudine Isaacs, MD, Lombardi Comprehensive Cancer Center, Georgetown University, 3800 Reservoir Rd NW, Corridor B, Room 414A, Washington, DC 20007 (isaacsc@georgetown.edu).

10.1001/jamaoncol.2026.2576

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