The FDA decision on Bristol Myers Squibb’s (BMY) Deucravacitinib, proposed for the treatment of adults with moderate to severe plaque psoriasis, is due on September 10.Deucravacitinib is designed to work as an oral, selective tyrosine kinase 2 (TYK2) inhibitor.TYK2, which belongs to the JAK protein tyrosine kinase family, mediates interleukin (IL)-23, IL-12, and interferon (IFN)a/ß signaling. IL-12, IL-23 and IFN a/ß are implicated in autoimmune diseases like psoriasis.Psoriasis is an autoimmune disease that affects more than 8 million adults in the U.S. About 90% of people with psoriasis have plaque psoriasis, which is characterized by "plaques," or raised, red areas of skin covered with a silver or white layer of dead skin cells. There are a number of approved systemic therapies, including biologic treatments, for the treatment of plaque psoriasis.If approved, Deucravacitinib would be the first TYK2 inhibitor approved for the treatment of any disease.The company expects Deucravacitinib to reach $4 billion in peak sales.BMY closed Friday’s trading at $71.19, down 0.43%.