The U.S. Food and Drug Administration has granted fast-track designation to Equillium Inc.'s itolizumab for treating kidney inflammation in lupus patients.

Fast-track designation gives regulatory priority to treatments that show promise, including frequent meetings with the FDA and priority review of the marketing application.

The San Diego-based biotechnology company started a phase 1b study called Equalise in September to evaluate the drug to treat patients with lupus and lupus nephritis.

Lupus is a chronic autoimmune disease that causes damage to the skin, joints and organs. Lupus nephritis specifically involves the kidneys, affecting about 100,000 patients in the U.S.