Alumis said on Tuesday its experimental drug to treat a common skin disease met the main goal in two late-stage studies, offering hope for a new oral treatment option that affects millions of Americans.

Shares of the South San Francisco-based company soared about 90% in premarket trading.

The drug, envudeucitinib, is being developed to treat moderate-to-severe plaque psoriasis, a chronic condition that causes red, scaly patches on the skin. Over 8 million people in the U.S. have psoriasis, according to the National Psoriasis Foundation.

In the trials, about 65% of patients saw their skin symptoms improve by 90% or more after 24 weeks of treatment. More than 40% of patients saw their symptoms clear up completely, the company said.

The drug also worked better than a placebo and outperformed Amgen's AMGN.O oral drug Otezla, Alumis added.

Leerink Partners analyst Thomas Smith said the drug offers "potential for class-leading TYK2 inhibition" and effectiveness approaching that of top-selling injectable drugs.

Envudeucitinib works by blocking TYK2, a protein that helps trigger immune signals linked to inflammation. This reduces the overactive immune response that causes psoriasis.

The company plans to seek U.S. regulatory approval for envudeucitinib in the second half of 2026. If cleared, it would compete with Bristol Myers Squibb's BMY.N Sotyktu, another drug in the same class approved for psoriasis in 2022.