Eluded by clear success in esophageal carcinoma, Merck touts subgroup OS win for Keytruda

Merck didn’t exactly get the clean sweep it wanted to show Keytruda beats out standard second-line therapy in esophageal or esophagogastric junction carcinoma — but the eager pharma giant insists that there’s cause for celebration.

Roy Baynes

In KEYNOTE-181, researchers set out to investigate whether the PD-1 checkpoint star can improve overall survival compared to chemotherapy. While that’s the case for a subgroup of patients whose tumors express PD-L1 (as quantified by a combined positive score, or CPS, of 10 or above), when it came to the entire intention-to-treat population, statistical significance for OS was not met — marking a key miss in the primary endpoint.

That failure kept investigators from formally testing the secondary endpoints, meaning that the data package to be sent to regulators won’t include progression-free survival and objective response rate.

An upbeat Merck, however, noted that OS was “directionally favorable” among the whole group, as it was for another cohort of patients with squamous cell histology.

Esophageal and esophagogastric junction carcinoma are notoriously hard to treat cancers, it added, and even demonstrating a survival benefit in patients with CPS ≥10 is a historic feat for an anti-PD-1 therapy.

“We are encouraged by these results of KEYTRUDA as monotherapy in previously-treated patients, and look forward to continuing our research efforts in this significant area of unmet need with our ongoing Phase 3 trial, KEYNOTE-590, evaluating KEYTRUDA in combination with chemotherapy as a first-line treatment for patients with esophageal carcinoma,” CMO Roy Baynes said in a statement.

Rivals are lining up their own shots at esophageal and esophagogastric cancers, with late-stage programs from Bristol-Myers Squibb as well as Celgene and BeiGene, which are slated to notch the 7th PD-1 approval in the US.

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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