Merck adopted a positive opinion recommending approval of KEYTRUDA, Merck's anti-PD-1 therapy, in combination with chemotherapy as neoadjuvant treatment, and then continued as monotherapy as adjuvant treatment after surgery for adults with locally advanced, or early-stage triple-negative breast cancer (TNBC) at high risk of recurrence. The CHMP's recommendation was based on results from the pivotal KEYNOTE-522 trial, which was the first Phase 3 study with an immunotherapy to show positive event-free survival (EFS) results in high-risk early-stage TNBC. As previously reported, after a median follow-up of 39 months, the KEYTRUDA regimen (neoadjuvant KEYTRUDA plus chemotherapy followed by adjuvant KEYTRUDA monotherapy) reduced the risk of events or death by 37% (HR=0.63 [95% CI, 0.48-0.82]; p<0.001) versus the chemotherapy-placebo regimen (neoadjuvant chemotherapy followed by adjuvant placebo) in these patients.

Event-free survival was defined as the time from randomization to the time of first occurrence of either disease progression that precluded definitive surgery, a local/distant recurrence, a second primary cancer, or death from any cause. Triple-negative breast cancer is an aggressive type of breast cancer, which has the highest risk of recurrence within the first five years after diagnosis and is associated with worse outcomes compared to other forms of breast cancer.