Study of Pembrolizumab (MK-3475) Versus Placebo in Combination With Neoadjuvant Chemotherapy & Adjuvant Endocrine Therapy in the Treatment of Early-Stage Estrogen Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative (ER+/HER2-) Breast Cancer (MK-3475-756/KEYNOTE-756)

Summary

The purpose of this study is to assess the efficacy and safety of pembrolizumab (MK-3475) versus placebo in combination with neoadjuvant (pre-surgery) chemotherapy and adjuvant (post-surgery) endocrine therapy in the treatment of adults who have high-risk early-stage estrogen receptor-positive, human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer. The primary study hypotheses are: 1) pembrolizumab is superior to placebo, both in combination with the protocol-specified neoadjuvant anticancer therapy, as assessed by pathological Complete Response (pCR) rate defined by the local pathologist, and 2) pembrolizumab is superior to placebo (both in combination with the protocol-specified neoadjuvant and adjuvant anticancer therapies) as assessed by Event-Free Survival (EFS) as determined by the investigator. The study is considered to have met its primary objective if pembrolizumab is superior to placebo with respect to either pCR (ypT0/Tis ypN0) or EFS.

Timeline

Start

2018-12-27

Primary completion

2031-01-24

Completion

2031-01-24

Publications

• Results Cardoso F, O'Shaughnessy J, Liu Z, McArthur H, Schmid P, Cortes J, Harbeck N, Telli ML, Cescon DW, Fasching PA, Shao Z, Loirat D, Park YH, Fernandez MG, Rubovszky G, Spring L, Im SA, Hui R, Takano T, Andre F, Yasojima H, Ding Y, Jia L, Karantza V, Tryfonidis K, Bardia A. Pembrolizumab and chemotherapy in high-risk, early-stage, ER+/HER2- breast cancer: a randomized phase 3 trial. Nat Med. 2025 Feb;31(2):442-448. doi: 10.1038/s41591-024-03415-7. Epub 2025 Jan 21.
• Schlam I, Corti C, Sammons S, Mittendorf EA, Tolaney SM. Checkpoint inhibition for early-stage hormone receptor-positive breast cancer. Expert Opin Biol Ther. 2024 Jun;24(6):511-520. doi: 10.1080/14712598.2024.2370395. Epub 2024 Jun 24.

Drugs

Indications