Pembrolizumab receives FDA accelerated approval to treat HER2-positive gastric cancer

On 5th May 2021, the United States Food and Drug Administration (US-FDA) granted its approval to pembrolizumab in combo with trastuzumab, platinum and fluoropyrimidine-containing chemotherapy for the first-line therapy of individuals having locally advanced unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-positive advanced gastric or gastroesophageal junction adenocarcinoma who did not previously receive systemic therapy for metastatic disease.

Considering the findings from a prespecified interim assessment of the first 264 subjects of the ongoing KEYNOTE-811 study, a randomized, placebo-controlled, double-blind, multicenter clinical trial in gastric cancer patients, the accelerated approval was given.

The enrolled subjects were randomly segregated to receive either 200 mg pembrolizumab or placebo every three weeks, in combo with trastuzumab and either oxaliplatin plus capecitabine or cisplatin plus fluorouracil. The primary endpoint ascertained was the overall response rate.

The overall response rate and the median duration of response were found to be higher in the pembrolizumab group compared to the placebo group, as shown in the table below:

 Table 1: Overall response rate and median duration of response

The adverse effect profile witnessed in individuals receiving pembrolizumab in Study KEYNOTE-811 displayed consistency with the well-known safety profile of pembrolizumab. For adults suffering from HER2-positive gastric cancer, the suggested dose of pembrolizumab in combo with chemotherapy and trastuzumab is 400 mg every six weeks or 200 mg every three weeks.

 Also read, Association between gastric cancer and H. pylori