Neoadjuvant pembrolizumab or placebo plus chemotherapy followed by adjuvant pembrolizumab or placebo for high-risk early-stage TNBC: Final analysis results from the phase 3 KEYNOTE-522 study.

Schmid P, Cortes J, Dent RA, McArthur HL, Pusztai L, Kuemmel S, Denkert C, Park YH, Hui R, Harbeck N, Takahashi M, Im SA, Untch M, Fasching P, Cardoso F, Hou S, Malhotra U, Beca F, O'Shaughnessy J (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Book Volume: 44

Pages Range: 507-507

Journal Issue: 16

DOI: 10.1200/JCO.2026.44.16_suppl.507

Abstract

507 Background: KEYNOTE-522 (NCT03036488) showed statistically significant and clinically meaningful improvements in pCR, EFS, and OS with the addition of pembrolizumab (pembro) to chemotherapy (chemo) in participants (pts) with high-risk early-stage TNBC. Here, we present updated results from the final analysis. Methods: Eligible pts with previously untreated, non-metastatic, centrally confirmed TNBC (stage T1c N1-2 or T2-4 N0-2 per AJCC) were randomized 2:1 to neoadjuvant pembro 200 mg Q3W or placebo (pbo), both given with 4 cycles of paclitaxel + carboplatin, then 4 cycles of doxorubicin or epirubicin + cyclophosphamide. After definitive surgery, pts received adjuvant pembro or pbo for 9 cycles or until recurrence or unacceptable toxicity. Dual primary endpoints are pCR (ypT0/Tis ypN0) and EFS (time from randomization to disease progression that precluded definitive surgery, local/distant recurrence, second primary cancer, or death from any cause); OS is the key secondary endpoint. Results: 1174 pts were randomized to pembro (n = 784) or pbo (n = 390). At the data cutoff date (October 14, 2025), median follow-up (range) was 93.8 mo (84.7-102.8). The 7-yr EFS rate (95% CI) was 78.3% (75.3-81.1) in the pembro group vs 69.8% (65.0-74.2) in the pbo group; the HR was 0.68 (95% CI, 0.54-0.86). The 7-yr OS rate (95% CI) was 85.1% (82.5-87.5) in the pembro group vs 77.2% (72.7-81.1) in the pbo group; the HR was 0.64 (95% CI, 0.49-0.85). The benefit of pembro on EFS and OS was generally consistent across most prespecified subgroups, including those defined by PD-L1 expression, nodal status, and disease stage. Rates of grade ≥3 treatment-related AEs were 77.1% in the pembro group and 73.3% in the pbo group (death incidence, 0.5% vs 0.3%, respectively); rates of any grade immune-mediated AEs were 35.0% vs 13.1%, respectively. Conclusions: After a median follow-up of 7.8 years, neoadjuvant pembro + chemo followed by adjuvant pembro continues to show a clinically meaningful survival benefit compared with neoadjuvant chemo alone in pts with high-risk early-stage TNBC.

Authors with CRIS profile

Involved external institutions

Philipps-Universität Marburg Germany (DE) Sungkyunkwan University (SKKU) Korea, Republic of (KR) Queen Mary University of London United Kingdom (GB) PANGAEA Oncology S.A. Spain (ES) University of Texas Southwestern Medical Center (UT Southwestern) United States (USA) (US) Yale University United States (USA) (US) National Cancer Centre Singapore (NCCS) Singapore (SG) Kliniken Essen-Mitte Germany (DE) Westmead Hospital Australia (AU) Klinikum der Universität München (LMU Klinikum) Germany (DE) Hokkaido University Hospital / 北海道大学病院 Japan (JP) Seoul National University (SNU) / 서울대학교 Korea, Republic of (KR) HELIOS Kliniken Germany (DE) Centre Antoine Lacassagne (UNICANCER) France (FR) Merck & Co., Inc. / Merck Sharp & Dohme Corp (MSD) United States (USA) (US) Baylor University Medical Center United States (USA) (US)

How to cite

APA:

Schmid, P., Cortes, J., Dent, R.A., McArthur, H.L., Pusztai, L., Kuemmel, S.,... O'Shaughnessy, J. (2026). Neoadjuvant pembrolizumab or placebo plus chemotherapy followed by adjuvant pembrolizumab or placebo for high-risk early-stage TNBC: Final analysis results from the phase 3 KEYNOTE-522 study. Journal of Clinical Oncology, 44(16), 507-507. https://doi.org/10.1200/JCO.2026.44.16_suppl.507

MLA:

Schmid, Peter, et al. "Neoadjuvant pembrolizumab or placebo plus chemotherapy followed by adjuvant pembrolizumab or placebo for high-risk early-stage TNBC: Final analysis results from the phase 3 KEYNOTE-522 study." Journal of Clinical Oncology 44.16 (2026): 507-507.

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