Date: March 19, 2025
On March 19, 2025, the U.S. Food and Drug Administration (FDA) granted traditional approval to pembrolizumab (Keytruda, Merck) in combination with trastuzumab and chemotherapy as a first-line treatment for adults with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction (GEJ) adenocarcinoma. This approval applies specifically to patients whose tumors express PD-L1 with a Combined Positive Score (CPS) of ≥1. This milestone follows an accelerated approval for the same indication in May 2021, now solidified by robust clinical trial data.
Video: “Breaking Down the FDA’s Pembrolizumab Approval”
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Video Description: A 2-minute animated explainer video featuring a narrator and visuals. The video opens with a depiction of gastric cancer cells, then transitions to a timeline showing pembrolizumab’s journey from accelerated approval in 2021 to full approval in 2025. Key stats from the KEYNOTE-811 trial (e.g., median PFS of 10.9 months vs. 7.3 months, OS of 20.1 months vs. 15.7 months) are highlighted with simple graphs. The video ends with a patient receiving treatment and a message of hope: “A new standard of care for HER2-positive gastric cancer patients.”
A Breakthrough in Treatment
The approval is based on results from the KEYNOTE-811 trial, a large, randomized, double-blind study involving 698 patients with HER2-positive advanced gastric or GEJ adenocarcinoma. Among them, 85% had tumors with PD-L1 CPS ≥1. Patients received either pembrolizumab (200 mg) or a placebo, alongside trastuzumab and chemotherapy (fluorouracil plus cisplatin or capecitabine plus oxaliplatin).
The trial demonstrated significant improvements:
- Progression-Free Survival (PFS): 10.9 months with pembrolizumab vs. 7.3 months with placebo.
- Overall Survival (OS): 20.1 months vs. 15.7 months.
- Overall Response Rate (ORR): 73% vs. 58%.
- Duration of Response (DOR): 11.3 months vs. 9.6 months.
These outcomes confirm pembrolizumab’s role in extending survival and delaying disease progression, offering a meaningful advance for patients facing this aggressive cancer.
Safety and Dosing
The safety profile of pembrolizumab in this trial aligned with its known effects, with no unexpected adverse reactions reported. The recommended dose is 200 mg every 3 weeks or 400 mg every 6 weeks, administered with trastuzumab and chemotherapy.
What This Means for Patients
For individuals battling HER2-positive gastric or GEJ adenocarcinoma, this approval marks a new standard of care. Full prescribing details will soon be available on Drugs@FDA, providing physicians with the latest guidance to optimize treatment.
Stay tuned for more updates on groundbreaking therapies transforming cancer care.
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