Regeneron Pharmaceuticals Stock Drops 10% on Melanoma Trial Fail

REGN shares tumbled more than 10% after a Phase III trial of its melanoma candidate failed to meet its primary endpoint, triggering a sharp single-day selloff. The miss removes a near-term oncology catalyst that bulls had been pricing into the late-stage pipeline.

The disappointment matters because Regeneron has been working to diversify away from concentration in Eylea, where biosimilar pressure on the original formulation is a known overhang. Oncology was viewed as one of the more credible long-duration growth vectors, and a failed melanoma readout pushes the timeline for that contribution materially to the right.

Management is likely to face questions on capital allocation, additional combo studies, and how aggressively to lean into Libtayo and earlier-stage assets. Watch the next earnings update for trial-design commentary, any partnership signals on the failed program, and consensus revisions to the oncology contribution line.

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