Pfizer has announced that its investigational oral Janus kinase 1 (JAK1) inhibitor abrocitinib (PF-04965842) has met all co-primary and secondary endpoints in a pivotal Phase III study evaluating safety and efficacy in patients aged 12 and older with moderate to severe atopic dermatitis.

The positive top-line results came from a randomised, double-blind, placebo-controlled, parallel-group study designed to evaluate the efficacy and safety of two doses - 100mg and 200mg once daily - of abrocitinib monotherapy over 12 weeks.

By week 12 the percentage of patients achieving each co-primary efficacy endpoint and each key secondary endpoint with either dose of abrocitinib was statistically significantly higher than placebo, demonstrating response to treatment for a statistically significant number of patients during the first two to four weeks following first dose.

The treatment is an oral small molecule that selectively inhibits Janus kinase (JAK) 1, which is thought to modulate multiple cytokines involved in pathophysiology of AD including interleukin (IL)-4, IL-13, IL-31, and interferon gamma.

Moderate to severe atopic dermatitis is a “chronic, inflammatory skin disease that can take both a physical and emotional toll on the millions of patients living with the condition worldwide,” said Michael Corbo, chief development officer, Inflammation & Immunology, Pfizer Global Product Development. “These top-line findings are encouraging and provide evidence that abrocitinib, if approved, could be an effective new oral once-daily treatment option for patients.”

Safety results show that both doses of abrocitinib were well-tolerated, and there were no unexpected safety events.

Abrocitinib received Breakthrough Therapy designation from the U.S. Food and Drug Administration (FDA) for the treatment of patients with moderate to severe AD in February 2018.