Bristol-Myers said Tuesday that its skin cancer drug nivolumab worked in a late-stage clinical trial, leading the drugmaker to end the study early.

Bristol-Myers said patients treated with nivolumab lived longer than patients who received only chemotherapy. The study compared the experimental treatment to an older drug called dacarbazine, and it was designed to evaluate nivolumab as a primary treatment for melanoma, the most dangerous type of skin cancer. Patients in the study had advanced melanoma with a specific genetic mutation.

The company did not report specific results from the trial, which enrolled 418 patients.

Shares of Bristol-Myers Squibb Co. rose $1.15, or 2.4 percent, to $49.45 in aftermarket trading. The stock rose 30 cents to $48.30 during the day.

Nivolumab hasn’t yet been approved, but Bristol-Myers Squibb is getting ready to file for approval of the drug as a treatment for non-small cell lung cancer. A drug regimen that combines nivolumab with an approved drug, Yervoy, has also showed promise as a treatment for melanoma.