Regeneron’s LAG-3 inhibitor missed its primary endpoint in a phase 3 melanoma trial, failing to beat Merck’s Keytruda in the study readout. Analysts cited the result as the second late-stage failure for a key Regeneron program within the past year, raising renewed questions about the company’s late pipeline risk profile. The outcome matters for LAG-3 strategy validation in melanoma and for how quickly investors and partners will re-rank next-wave checkpoint combinations. It also intensifies scrutiny around endpoint selection and trial design choices in head-to-head immuno-oncology studies. The company now faces decisions on how to reposition the program and what additional data would be needed to support future development steps.