Perioperative Pembrolizumab Nearly Doubles 5-Year Event-Free Survival in Patients With Resectable Non-Small Cell Lung Cancer

Clinical Summary: 

• Design/Population: KEYNOTE-671 was a randomized phase 3 trial evaluating perioperative pembrolizumab plus neoadjuvant platinum-doublet chemotherapy vs neoadjuvant chemotherapy and surgery alone in patients with previously untreated, resectable stage II, IIIA, or IIIB non-small cell lung cancer (NSCLC).
• Key Outcomes: At 5 years, event-free survival was 49.9% with perioperative pembrolizumab vs 26.5% with placebo, while overall survival was 64.6% vs 53.6%, respectively. No detriment to health-related quality of life was identified with longer follow-up.
• Clinical Relevance: The sustained event-free and overall survival advantages at 5 years demonstrate the durability of perioperative pembrolizumab in resectable early-stage NSCLC, strengthening its role as a standard-of-care strategy without evidence of a long-term quality-of-life tradeoff.

Five-year follow-up results from the phase 3 KEYNOTE-671 trial demonstrated that perioperative pembrolizumab plus neoadjuvant chemotherapy sustained survival benefit compared with neoadjuvant chemotherapy and surgery alone in patients with resectable early-stage non-small cell lung cancer (NSCLC). 

In this trial, 797 previously untreated patients with resectable stage II, IIIA, or IIIB NSCLC were randomized 1:1 to receive 4 cycles of either 200 mg of pembrolizumab (n = 397) or placebo (n = 400) once every 3 weeks plus platinum-doublet chemotherapy, followed by surgery and adjuvant pembrolizumab or placebo once every 3 weeks for up to 13 cycles. Primary end points included event-free survival (EFS) and overall survival (OS). 

At a median follow-up of 60.4 months, the 5-year EFS rate was 49.9% in the pembrolizumab arm and 26.5% in the placebo arm, corresponding to a 42% reduction in the risk of an event. The 5-year OS rates were 64.6% and 53.6%, respectively.

Long-term treatment benefit was not accompanied by an identified detriment to health-related quality of life with perioperative pembrolizumab compared with placebo. Safety findings remained consistent with the known profiles of the individual treatments.

“After 5 years of follow-up, EFS was nearly double with perioperative pembrolizumab plus neoadjuvant chemotherapy, along with continued improvement in OS compared with neoadjuvant chemotherapy and surgery alone,” concluded study authors. “The durable and clinically meaningful benefits observed support use of this treatment as a standard of care for patients with resectable early-stage NSCLC.” 

Source: 

Wakelee H. Spicer JD, Gao S, et al. Five-year outcomes of perioperative pembrolizumab for early-stage non-small cell lung cancer from the randomized KEYNOTE-671 study. Ann Oncol. Published online: August 21, 2026. doi: 10.1016/j.annonc.2026.08.005