Shares of Vera Therapeutics rose about 8% Tuesday after the Food and Drug Administration approved its treatment for a kidney disease, IgA nephropathy, that affects about 160,000 people in the U.S. and often leads to kidney failure.

The drug, called Trutakna, works by blocking two proteins that push the immune system to make antibodies that build up in the kidneys and cause damage. It is the first drug approved in the U.S. that targets both proteins at once, though several other drugs already treat the disease. Vertex Pharmaceuticals is chasing a similar drug that also blocks both proteins, which the FDA is due to rule on later this year.

-- The accelerated approval was based on an interim look at Vera's ongoing Phase 3 trial, before the study is complete. Patients on Trutakna saw a 46% drop in a urine-protein marker doctors use to track kidney damage. That equated to a 42% bigger drop than placebo patients saw.

-- "We've really changed expectations for the disease," said Dr. Richard Lafayette, a nephrologist at Stanford University Medical Center who helped lead the trial.