Yeon Hee Park, Rina Hui, Seock-Ah Im, Jin-Hee Ahn, Chiun-Sheng Huang, Min Hwan Kim, Shin-Cheh Chen, Hirofumi Mukai, Masato Takahashi, Hiroji Iwata, Javier Cortés, Heather McArthur, Lajos Pusztai, Sherko Kümmel, Carsten Denkert, Joyce O'Shaughnessy, Nadia Harbeck, Peter A Fasching, Michael Untch, Fatima Cardoso, Liyi Jia, Francisco Beca, Jaime Mejia, Rebecca Dent, Peter Schmid
OS and updated EFS outcomes in KEYNOTE-522 participants enrolled in Asia were consistent with those in the overall population and support use of perioperative pembrolizumab + neoadjuvant chemotherapy as a standard-of-care treatment in this setting.
BACKGROUND: In KEYNOTE-522 (NCT03036488), addition of perioperative pembrolizumab to neoadjuvant chemotherapy significantly improved pathological complete response (pCR), event-free survival (EFS), and overall survival (OS) in early-stage triple-negative breast cancer (TNBC). pCR and EFS results in participants enrolled in Asia were consistent with those in the overall population. We report OS, updated EFS, and safety outcomes in participants enrolled in Asia.
METHODS: Participants with newly diagnosed, high-risk, early-stage TNBC (T1c [N1‒N2] or T2‒T4 [N0‒N2] per AJCC 7th edition) were randomized 2:1 to 8 cycles of neoadjuvant pembrolizumab 200 mg Q3W or placebo plus chemotherapy. After definitive surgery, participants received adjuvant pembrolizumab 200 mg Q3W or placebo for ≤9 cycles. Primary endpoints were pCR (ypT0/Tis ypN0) and EFS. OS was a secondary endpoint.
RESULTS: Of 1174 randomized participants, 216 were enrolled in Asia. At data cutoff (March 22, 2024), EFS events occurred in 18/136 participants (13.2%) in the pembrolizumab + chemotherapy group versus 22/80 (27.5%) in the placebo + chemotherapy group (HR, 0.43 [95% CI, 0.23‒0.81]); 60-month EFS rates (95% CIs) were 87.4% (80.6%‒92.0%) and 72.1% (60.7%‒80.6%), respectively. In the respective groups, 12/136 (8.8%) and 16/80 participants (20.0%) died (HR, 0.41 [95% CI, 0.19‒0.86]); 60-month OS rates (95% CIs) were 91.9% (85.8%‒95.4%) and 81.1% (70.5%‒88.1%). Treatment-related AEs led to treatment discontinuation in 19/136 participants (14.0%) with pembrolizumab + chemotherapy and 7/79 (8.9%) with placebo + chemotherapy.
CONCLUSIONS: OS and updated EFS outcomes in KEYNOTE-522 participants enrolled in Asia were consistent with those in the overall population and support use of perioperative pembrolizumab + neoadjuvant chemotherapy as a standard-of-care treatment in this setting.