Neo/Adjuvant Pembrolizumab Significantly Improves Overall Survival for Patients With Early-Stage Triple-Negative Breast Cancer

Final Overall Survival Results From the Phase 3 KEYNOTE-522 Trial 

According to results from the phase 3 KEYNOTE-522 trial, neoadjuvant pembrolizumab plus chemotherapy followed by adjuvant pembrolizumab significantly improved overall survival (OS) among patients with early-stage triple-negative breast cancer (TNBC).  

In this double-blind, placebo-controlled trial, 1174 previously untreated patients with stage 2 or 3 TNBC were randomized on a 2-to-1 basis to receive either 200 mg of pembrolizumab (n = 784) or placebo (n = 390) every 3 weeks plus paclitaxel and carboplatin followed by 4 cycles of pembrolizumab or placebo plus doxorubicin and cyclophosphamide or epirubicin and cyclophosphamide. After patients underwent surgical resection, followed by additional pembrolizumab or placebo every 3 weeks for up to 9 cycles. Results from the first-interim analysis “showed significant improvements in pathological complete response and event-free survival with the addition of pembrolizumab to platinum-containing chemotherapy,” stated Peter Schmid, MD, Barts Cancer Institute, London, United Kingdom. The primary end point for this analysis, reported here, was OS. A key secondary end point was safety. 

At a median follow-up of 75.1 months, the estimated OS was 86.6% in the pembrolizumab arm and 81.7% in the placebo arm. The restricted mean survival time was 55.3 months and 54.1 months, respectively. Treatment-related adverse events occurred in 77.1% of patients in the pembrolizumab arm and 73.3% of patients in the placebo arm. The most common events included neutropenia, decreased neutrophil count, and anemia. Serious treatment-related adverse events occurred in 34.1% of patients in the pembrolizumab arm and 20.1% of patients in the placebo arm. Treatment-related adverse events led to death in 4 patients in the pembrolizumab arm and 1 patient in the placebo arm.

“These results provide further support for pembrolizumab plus neoadjuvant chemotherapy followed by adjuvant pembrolizumab as treatment for high-risk, early-stage triple-negative breast cancer,” concluded Dr Schmid et al. 

Source: 

Schmid P, Cortes J, Dent R, et al. Overall survival with pembrolizumab in early-stage triple-negative breast cancer. N Engl J Med. Published online: September 15, 2024. doi: 10.1056/NEJMoa2409932