KEYTRUDA Shows Promising Survival Benefits in Gastric Cancer: Phase 3 Trial

Merck announced that its KEYNOTE-811 trial of KEYTRUDA® in combination with chemotherapy met its primary goal, significantly improving survival rates for patients with advanced HER2-positive gastric cancer. The FDA has granted accelerated approval for this treatment, with further results and global regulatory discussions pending.

According to a statement from Merck, the KEYNOTE-811 trial met its dual primary endpoint of overall survival (OS). This study evaluated KEYTRUDA® (pembrolizumab) in combination with trastuzumab and a chemotherapy regimen containing fluoropyrimidine and platinum, specifically for patients with HER2-positive advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma.

Dr. Marjorie Green, Senior Vice President and Head of Oncology at Merck Research Laboratories, emphasized the importance of these findings, stating, "Patients diagnosed with advanced gastric cancer often face a poor prognosis. These overall survival results from KEYNOTE-811 are encouraging and build on the positive progression-free survival, overall response rate and duration of response data from this study.”

The Phase 3 KEYNOTE-811 Trial

The  trial focused on patients with locally advanced unresectable or metastatic HER2-positive gastric or GEJ adenocarcinoma. The results demonstrated a statistically significant and clinically meaningful improvement in overall survival for patients treated with KEYTRUDA, compared to those receiving a placebo, alongside the same chemotherapy and trastuzumab regimen. This success is particularly notable in patients whose tumors express PD-L1 (CPS ≥1), a protein that can help predict the response to immunotherapy.

FDA Approval and Treatment Implications

Following these findings, the U.S. Food and Drug Administration (FDA) has granted accelerated approval for KEYTRUDA in this combination as a first-line treatment. This approval is contingent on further validation and description of clinical benefits from the final analysis of the KEYNOTE-811 study, which Merck continues to conduct.

Safety and Efficacy

KEYTRUDA is currently being studied across multiple types of gastrointestinal cancers, including gastric, hepatobiliary, esophageal, and colorectal cancers. The safety profile of KEYTRUDA in the KEYNOTE-811 trial aligns with previous studies, with no new safety concerns identified. This consistency supports the therapy's use in a broader patient population.