An experimental drug from Amgen Inc. has proven successful in treating moderate to severe psoriasis, the company announced Tuesday.

The Thousand Oaks biopharmaceutical company is in a partnership with AstraZeneca to develop brodalumab, an injectable that inhibits inflammatory signaling by cells. In addition to psoriasis, investigators are trying to see if it can treat psoriatic arthritis and asthma.

The study involved more than 1,800 patients with some receiving brodalumab every two weeks, some receiving Johnson & Johnson’s drug Stelara and another group receiving a placebo. After 12 weeks, the results showed “a significantly greater proportion of patients treated with brodalumab” had clear skin compared to the placebo. In addition, brodalumab was “superior to Stelara on the primary endpoint of achieving total clearance of skin disease,” according to Amgen.

The study was the final Phase 3 trial for the drug.

Shares of Amgen closed up $2.48, or 1.5 percent, to $164.72 on the Nasdaq.