EARLY TNBC BENEFITS FROM PEMBROLIZUMAB AND CHEMOTHERAPY
LBA8_PR: KEYNOTE-522: Phase 3 study of pembrolizumab (pembro) + chemotherapy (chemo) vs placebo (pbo) + chemo as neoadjuvant treatment, followed by pembro vs pbo as adjuvant treatment for early triple-negative breast cancer (TNBC)
Peter Schmid
Dr. Peter Schmid (Barts Cancer Institute – Queen Mary University of London, London, UK) reviewed the results of the phase III study KEYNOTE-522, which compared pembrolizumab + chemotherapy to chemotherapy + placebo in untreated early-stage triple-negative breast cancer patients. Randomized patients received both neoadjuvant and adjuvant interventions. The study had dual endpoints: pathological complete response (defined as ypT0/Tis ypN0) and event-free survival.
A statistically significant improvement in pCR was observed for the pembrolizumab combination over the placebo combination, with rates of 64.8% and 51.2% (P=0.00055) respectively. When patients were stratified by PD-L1 expression, similar trends were noted: pCR in PD-L1+ patients was 68.9% vs 54.9% for pembrolizumab vs placebo; at the same time, pCR in PD-L1- was 45.3% vs 30.3%. Event-free survival was also extended in the pembrolizumab arm, leading to a HR of 0.63. Safety profiles were similar across the entire study. Early TNBC may thus benefit from pembrolizumab and chemotherapy treatment, both before and after surgery.