FDA Approves Frontline Pembrolizumab for HER2+ Gastric, GEJ Cancer

The Food and Drug Administration (FDA) granted an accelerated approval to pembrolizumab (Keytruda) plus trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy for the frontline treatment of patients with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction (GEJ) adenocarcinoma.

The approval was based on interim findings from the ongoing multicenter, randomized, double-blind, placebo-controlled KEYNOTE-811 trial. The trial included 264 patients with HER2-positive advanced gastric or GEJ adenocarcinoma who had not previously received systemic therapy for metastatic disease. Half the patients received 200 mg of pembrolizumab every 3 weeks in combination with trastuzumab and either fluorouracil plus cisplatin or capecitabine plus oxaliplatin.

The overall response rate, as assessed by a blinded independent review committee, was 74% in the pembrolizumab arm, and 52% in the placebo arm. Average duration of response was 10.6 months (range 1.1 months to 16.5 months) for the immunotherapy agent, compared with 9.5 months (range, 1.4 months to 15.4 months) for the placebo arm.

Researchers said that the adverse event profile observed in KEYNOTE-811 is consistent with the known safety profile of the drug.

The recommended dosing for this patient population is 200 mg of pembrolizumab every 3 weeks or 400 mg every 6 weeks.

Reference

FDA. FDA grants accelerated approval to pembrolizumab for HER2-postive gastric cancer. May 5, 2021. https://www.fda.gov/drugs/drug-approvals-and-databases/fda-grants-accelerated-approval-pembrolizumab-her2-positive-gastric-cancer?utm_medium=email&utm_source=govdelivery Accessed May 5, 2021.