Study of Pembrolizumab (MK-3475) Plus Chemotherapy vs Placebo Plus Chemotherapy as Neoadjuvant Therapy and Pembrolizumab vs Placebo as Adjuvant Therapy in Participants With Triple Negative Breast Cancer (TNBC) (MK-3475-522/KEYNOTE-522)

Summary

The purpose of this study is to evaluate the efficacy and safety of pembrolizumab (MK-3475) plus chemotherapy vs placebo plus chemotherapy as neoadjuvant therapy and pembrolizumab vs placebo as adjuvant therapy in participants who have triple negative breast cancer (TNBC). After a screening phase of approximately 28 days, each participant will receive neoadjuvant study treatment (Pembrolizumab + Chemotherapy OR Placebo + Chemotherapy) based on the randomization schedule for approximately 24 weeks (8 cycles). Each participant will then undergo definitive surgery 3-6 weeks after conclusion of the last cycle of the neoadjuvant study treatment. After definitive surgery, each participant will receive adjuvant study treatment (Pembrolizumab OR Placebo) for approximately 27 weeks (9 cycles). Following adjuvant study treatment, each participant will be monitored for safety, survival and disease recurrence. The primary study hypothesis is that pembrolizumab is superior to placebo, in combination with chemotherapy, as measured by the rate of Pathological Complete Response (pCR) and/or Event-free Survival (EFS), in participants with locally advanced TNBC.

Timeline

Start

2017-03-07

Primary completion

2025-10-14

Completion

2025-10-14

Publications

• Results Schmid P, Cortes J, Dent R, McArthur H, Pusztai L, Kummel S, Denkert C, Park YH, Hui R, Harbeck N, Takahashi M, Im SA, Untch M, Fasching PA, Mouret-Reynier MA, Foukakis T, Ferreira M, Cardoso F, Zhou X, Karantza V, Tryfonidis K, Aktan G, O'Shaughnessy J; KEYNOTE-522 Investigators. Overall Survival with Pembrolizumab in Early-Stage Triple-Negative Breast Cancer. N Engl J Med. 2024 Nov 28;391(21):1981-1991. doi: 10.1056/NEJMoa2409932. Epub 2024 Sep 15.
• Kuemmel S, Fasching PA, Schmid P, Harbeck N, Takahashi M, Untch M, Boileau JF, Cortes J, Dent R, O'Shaughnessy J, Pusztai L, Foukakis T, Park YH, Hui R, Cardoso F, Denkert C, Jia L, Pan W, Karantza V, McArthur H. Surgical Outcomes After Neoadjuvant Pembrolizumab Plus Chemotherapy for Triple-Negative Breast Cancer: Results from the Randomized, Placebo-Controlled Phase 3 KEYNOTE-522 Study. Ann Surg Oncol. 2026 Jun;33(6):5550-5557. doi: 10.1245/s10434-026-19121-2. Epub 2026 Feb 25.
• Takahashi M, Mukai H, Takano T, Tsugawa K, Inoue K, Itoh M, Watanabe J, Tanabe Y, Yamamoto N, Miyoshi Y, Watanabe K, Mukohara T, Kong Y, Shimura M, Beca F, Schmid P, Iwata H. Pembrolizumab for Early-Stage Triple-Negative Breast Cancer: KEYNOTE-522 Japan Subgroup Analysis. Cancer Sci. 2026 Apr;117(4):1106-1116. doi: 10.1111/cas.70307. Epub 2026 Jan 14.
• Dent R, Cortes J, Pusztai L, McArthur H, Kummel S, Bergh J, Denkert C, Park YH, Hui R, Harbeck N, Takahashi M, Untch M, Fasching PA, Cardoso F, Haiderali A, Jia L, Nguyen AM, Pan W, O'Shaughnessy J, Schmid P. Neoadjuvant pembrolizumab plus chemotherapy/adjuvant pembrolizumab for early-stage triple-negative breast cancer: quality-of-life results from the randomized KEYNOTE-522 study. J Natl Cancer Inst. 2024 Oct 1;116(10):1654-1663. doi: 10.1093/jnci/djae129.
• Favre-Bulle A, Huang M, Haiderali A, Bhadhuri A. Cost-Effectiveness of Neoadjuvant Pembrolizumab plus Chemotherapy Followed by Adjuvant Pembrolizumab in Patients with High-Risk, Early-Stage, Triple-Negative Breast Cancer in Switzerland. Pharmacoecon Open. 2024 Jan;8(1):91-101. doi: 10.1007/s41669-023-00445-8. Epub 2023 Nov 24.
• Takahashi M, Cortes J, Dent R, Pusztai L, McArthur H, Kummel S, Denkert C, Park YH, Im SA, Ahn JH, Mukai H, Huang CS, Chen SC, Kim MH, Jia L, Li XT, Tryfonidis K, Karantza V, Iwata H, Schmid P. Pembrolizumab Plus Chemotherapy Followed by Pembrolizumab in Patients With Early Triple-Negative Breast Cancer: A Secondary Analysis of a Randomized Clinical Trial. JAMA Netw Open. 2023 Nov 1;6(11):e2342107. doi: 10.1001/jamanetworkopen.2023.42107.
• Schmid P, Cortes J, Dent R, Pusztai L, McArthur H, Kummel S, Bergh J, Denkert C, Park YH, Hui R, Harbeck N, Takahashi M, Untch M, Fasching PA, Cardoso F, Andersen J, Patt D, Danso M, Ferreira M, Mouret-Reynier MA, Im SA, Ahn JH, Gion M, Baron-Hay S, Boileau JF, Ding Y, Tryfonidis K, Aktan G, Karantza V, O'Shaughnessy J; KEYNOTE-522 Investigators. Event-free Survival with Pembrolizumab in Early Triple-Negative Breast Cancer. N Engl J Med. 2022 Feb 10;386(6):556-567. doi: 10.1056/NEJMoa2112651.
• Perez-Garcia J, Soberino J, Racca F, Gion M, Stradella A, Cortes J. Atezolizumab in the treatment of metastatic triple-negative breast cancer. Expert Opin Biol Ther. 2020 Sep;20(9):981-989. doi: 10.1080/14712598.2020.1769063. Epub 2020 May 25.
• Schmid P, Cortes J, Pusztai L, McArthur H, Kummel S, Bergh J, Denkert C, Park YH, Hui R, Harbeck N, Takahashi M, Foukakis T, Fasching PA, Cardoso F, Untch M, Jia L, Karantza V, Zhao J, Aktan G, Dent R, O'Shaughnessy J; KEYNOTE-522 Investigators. Pembrolizumab for Early Triple-Negative Breast Cancer. N Engl J Med. 2020 Feb 27;382(9):810-821. doi: 10.1056/NEJMoa1910549.

Drugs

Indications