Gilead Sciences Inc.'s combination treatment did not induce a response in patients with a type of liver disease without the appearance of new scarring in the liver, failing the main goal of a mid-stage clinical trial.

Foster City, Calif.-based Gilead tested cilofexor, firsocostat and selonsertib in various combinations and alone in patients with fibrosis, or scarring in the liver, due to nonalcoholic steatohepatitis, or NASH.

NASH is a progressive liver disease that can result in cirrhosis, liver failure, cancer and death. Liver fibrosis can cause chronic liver failure. The disease is a type of non-alcoholic fatty liver disease, which causes fat to build up in the liver.

The trial, called Atlas, enrolled 392 patients to test the drugs' safety and see whether the therapies would improve symptoms of NASH without scarring. At the end of 48 weeks, none of the regimens met the main goal, but Gilead said some improvements were seen in fibrosis and liver function in patients with advanced fibrosis taking firsocostat and cilofexor.

The three drugs in combination or alone were generally well-tolerated in the phase 2 Atlas study. Adverse events were mild, including itching, headache, diarrhea and nausea.

Gilead previously discontinued a study called Stellar that specifically looked at selonsertib as a single therapy for treating NASH, after the therapy failed to reduce scarring in several different arms of the trial.

Chief Medical Officer Merdad Parsey said the firsocostat and cilofexor results suggest success could be found with the NASH program in advanced fibrosis. The company plans to present more detailed results from Atlas at a future medical meeting.