Merck Voluntarily Withdraws KEYTRUDA's Accelerated Approval for Third-Line Gastric Cancer in the U.S.

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On July 1, Eastern Time, MSD announced on its official website that it is voluntarily withdrawing a previously accelerated FDA approval for one indication of Keytruda, specifically for the treatment of patients with recurrent locally advanced or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 [Combined Positive Score (CPS) ≥ 1]. This decision follows the failure of a post-approval confirmatory trial to demonstrate clinical benefit for the drug.

The decision was made in consultation with the FDA following the Oncologic Drugs Advisory Committee’s evaluation on April 29 of Keytruda’s indication as a monotherapy for third-line gastric cancer, as Keytruda did not meet the post-marketing requirement to demonstrate an overall survival benefit in a Phase 3 study. In accordance with the agreement with the FDA, MSD will initiate the withdrawal of the accelerated approval for this indication within six months. Patients with metastatic gastric cancer receiving Keytruda as a third-line or later treatment should discuss their care with their healthcare providers. This decision does not affect other indications for Keytruda.

The initial accelerated approval for Keytruda was granted in September 2017, and it retains accelerated approval indications for three other distinct types of gastric cancer, all of which were approved based on tumor response rate and duration of response. Keytruda will continue to play an important role in the treatment of certain patients with gastric cancer:

• In combination with trastuzumab and fluoropyrimidine- and platinum-containing chemotherapy for the first-line treatment of patients with HER2-positive locally advanced unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma.
• For the treatment of adult and pediatric patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumors, including those that have progressed following prior treatment and who have no satisfactory alternative treatment options. The safety and efficacy of Keytruda in pediatric patients with MSI-H central nervous system tumors have not been established.
• Indicated for the treatment of adult and pediatric patients with unresectable or metastatic solid tumors with high tumor mutational burden (TMB-H, ≥10 mutations/megabase) that have progressed following prior treatment and who have no satisfactory alternative treatment options. The safety and efficacy of Keytruda for the treatment of pediatric TMB-H central nervous system tumors have not been established.

MSD's clinical program in gastric cancer includes three first-line Phase III trials: KEYNOTE-811, KEYNOTE-859, and LEAP-015, as well as KEYNOTE-585 for neoadjuvant and adjuvant treatment.

Source: Merck Provides Update on KEYTRUDA^® (pembrolizumab) Indication in Third-Line Gastric Cancer in the US