Regeneron Pharmaceuticals (RENG.US) saw its shares drop sharply, falling over 10% in early trading on Monday to hit a new low for the year at $623.67. The decline followed the company's announcement of preliminary results from a Phase 3 clinical trial for its investigational drug fianlimab, combined with Libtayo as a first-line treatment for unresectable locally advanced or metastatic melanoma. The trial failed to meet its primary endpoint.

The randomized, double-blind study involved 1,546 patients. Results indicated that the median progression-free survival was 11.5 months for the high-dose combination therapy group, compared to 6.4 months for the control group treated with Merck's Keytruda alone. Although this represents a numerical improvement of 5.1 months, the hazard ratio was 0.845 with a p-value of 0.0627, which did not cross the threshold for statistical significance.