Merck's Keytruda misses the mark in second-line stomach cancer study

Merck's Keytruda won an FDA approval in September in third-line stomach cancer.

Merck’s Keytruda boasts an FDA approval in third-line stomach cancer, but its ambitions for moving earlier into treatment just took a hit.

On Thursday, the company said its immuno-oncology star had missed its primary endpoint in a phase 3, second-line gastric cancer trial, failing to extend the lives of patients with PD-L1-expressing tumors. And the medication couldn’t significantly hold off disease progression in that population, either.

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The bad news won’t affect Keytruda’s current indication, which it nabbed in September. And it also won’t stop Merck from trialing Keytruda even earlier in the treatment process, the company said. It’s pushing forward with a phase 3 study looking at Keytruda—both solo and in tandem with chemo—as a first-line treatment for PD-L1-positive patients, as well as with a phase 3 study examining a Keytruda-chemo combo in the presurgery setting.

Analysts, though, aren't expecting much from these studies at this point, Barclays analyst Geoff Meacham wrote in a note to clients. The trials are "likely out of consensus assumptions and would represent upside if positive," he said.

The flop add to the list of misfires for Keytruda and the PD-1/PD-L1 class in general, which over the past couple of years has proven to be less predictable than industry watchers once thought. Since Bristol-Myers Squibb’s Opdivo shocked Wall Street with a front-line monotherapy failure in lung cancer, members of the class have faltered in trials across multiple tumor types.

RELATED: Keytruda fail 'small beans' for Merck, bigger riddle for immuno-oncology scorekeepers

Keytruda, for its part, came up short of its goal in a head and neck cancer trial in July—a goal that Opdivo had already hit. That outcome challenged the notion that Merck may just be “executing these trials” much better than rivals whose drugs had stumbled in other areas, Evercore ISI analyst Umer Raffat wrote to clients at the time.

Earlier in the summer, the New Jersey drugmaker put the kibosh on a trio of multiple myeloma stars after a data monitoring committee flagged an imbalance in patient deaths.