Merck & Co withdraws Keytruda’s US approval in third-line stomach cancer

Merck & Co has announced that it will voluntarily withdraw a US Food and Drug Administration (FDA) accelerated approval for Keytruda in third-line stomach cancer.

In a statement, Merck & Co – known as MSD outside the US and Canada – said that it made the decision to withdraw Keytruda’s (pembrolizumab) accelerated approval in this indication after it failed to meet its post-marketing requirements.

The FDA initially approved Keytruda using its accelerated approval pathway based on results from the KEYNOTE-059 study in 259 patients, 143 of whom were PD-L1 expressers above the threshold for entry into the trial.

Among these, Keytruda achieved an overall response rate of just over 13% (19 patients), with a complete response rate of 1.4%. Around half the responders lived for six months and longer, with a quarter surviving beyond 12 months.

However, the checkpoint inhibitor was unable to demonstrate an overall survival benefit for patients with recurrent locally-advanced or metastatic gastric or gastroesophageal junction cancer when used as a third-line option after chemotherapy.

“While there remains an unmet need for heavily pre-treated patients with advanced gastric cancer, we recognise that the treatment landscape has evolved and we respect the FDA’s efforts to continually evaluate accelerated approvals,” said Scot Ebbinghaus, vice president, clinical research, Merck Research Laboratories.

“Our research with Keytruda has contributed to recent advances in the treatment of gastric cancer, and we are continuing to advance studies to help more patients with this disease,” he added.

Keytruda is still approved in combination with Roche’s Herceptin (trastuzumab), fluoropyrimidine- and platinum-containing chemotherapy for the first-line treatment of patients with locally advanced unresectable or metastatic HER2-positive gastric or GEJ adenocarcinoma.

In April, the FDA’s oncology advisory committee rejected the continued accelerated approval of Keytruda as a third-line option for stomach cancer patients as part of an agency-wide review.

That decision follows an FDA announcement earlier this year that it would convene an advisory committee meeting to discuss six oncology indications with accelerated approvals, amid a major review of cancer drugs that have failed to meet post-marketing requirements.

This included approvals for not only Keytruda, but also Roche’s Tecentriq (atezolizumab) and Bristol Myers Squibb’s (BMS) Opdivo (nivolumab) in a number of cancer types.