Dermira Inc. shares soared 83% in premarket trade Monday, after the biotech reported positive results in a mid-stage trial of a treatment for moderate-to-severe atopic dermatitis. The Menlo Park, Calif.-based company said a phase 2b trial of Lebrikizumab met its primary endpoint of demonstrating greater improvements in the Eczema Area and Severity Index score (EASI) compared to placebo. The safety profile was consistent with prior studies. Lebrikizumab is an injectable, humanized monoclonal antibody that's designed to specifically block the action of interleukin-13, or IL-13, a substance secreted by certain cells of the immune system that is a central pathogenic mediator in atopic dermatitis. The study involved 280 patients. Atopic dermatitis is a common and severe form of eczema characterized by rashes on the skin that can cover much of the body and include redness, cracking, dryness and intense itching. Dermira shares have fallen 24.8% in the last 12 months, while the S&P 500 has gained 2.6%.