New Data Emerge from KEYNOTE-091 Regarding Adjuvant Pembrolizumab in Early NSCLC


Recently presented data from the KEYNOTE-091 trial show a trend toward survival benefit with adjuvant pembrolizumab in patients with resected non–small cell lung cancer, especially in patients with PD-L1–positive disease.

Updated findings from the pivotal phase 3 KEYNOTE-091 trial (also known as the PEARLS trial; NCT02504372) of pembrolizumab (Keytruda) as adjuvant treatment for patients with stage IB to IIIA non–small cell lung cancer (NSCLC) showed superior disease-free survival (DFS) outcomes with active therapy vs placebo.

Results were presented as part of the European Society for Medical Oncology (ESMO) Virtual Plenary series.

“These are the first positive results for Keytruda in the adjuvant setting for non–small cell lung cancer and represent the sixth positive pivotal study evaluating a Keytruda-based regimen in earlier stages of cancer,” Roy Baynes, MD, PhD, senior vice president and head of global clinical development, as well as chief medical officer for Merck Research Laboratories, said in a statement. “Keytruda has become foundational in the treatment of metastatic non–small cell lung cancer, and we are pleased to present these data showing the potential of Keytruda to help more patients with lung cancer in earlier stages of disease. We thank the patients, their caregivers, and investigators for participating in this study.”

Previously reported data from the trial made available in January 2022 indicated that DFS in the PD-L1–positive cohort, defined by having a tumor proportion score (TPS) of 50% or higher, improved with pembrolizumab. However, investigators noted that the study’s dual primary end points did not meet statistical significance by the pre-specified statistical plan.

Data showed an 18% reduction in the risk of disease recurrence or death in the PD-L1–positive population (HR, 0.82; 95% CI, 0.57-1.18; P = .14), and median DFS was not reached in either arm. In addition, there was a trend toward favorable overall survival (OS) in all patients, regardless of PD-L1 expression (HR, 0.87; 95% CI, 0.67-1.15; P = .17).

Given these results, the trial will continue to evaluate DFS in a population of patients with PD-L1 TPS of 50% or more and OS.

“While significant advancements have been made in the treatment of metastatic non–small cell lung cancer, there remains an unmet need for patients with earlier stages of this disease, as up to 43% of them will experience disease recurrence following surgery,” Luis Paz-Ares, MD, PhD, chair of medical oncology at Hospital Universitario Doce de Octubre in Madrid, Spain, and co-principal investigator on the trial, said in a statement. “The positive disease-free survival data observed in this study with the use of Keytruda in the adjuvant setting has the potential to have important implications for how we treat patients with stage IB to IIIA non–small cell lung cancer.”


Merck’s Keytruda (pembrolizumab) significantly improved disease-free survival (DFS) versus placebo as adjuvant therapy in patients with stage IB-IIIA non-small cell lung cancer (NSCLC) regardless of PD-L1 expression. New release. Merck. March 17, 2022. Accessed March 18, 2022.

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