There are no FDA approved topical treatments for psoriasis. Topically formulated corticosteroids and vitamin D analogues are used to treat patients with mild to moderate psoriasis. These therapies have significant side effects, particularly when administered chronically and are contraindicated for many segments of the disease population.
Systemic therapies for psoriasis fall into two categories, oral small-molecule drugs and injectable biologics.
Injectable biologics block cells and proteins in the immune system, such as the pro-inflammatory cytokines interleukin 17A (IL-17A) or interleukins 12 and 23 (IL-12/IL-23). These proteins are drivers of a variety of human autoimmune diseases beyond psoriasis, such as rheumatoid arthritis, lupus, inflammatory bowel disease and multiple sclerosis. There are a number of approved biologic drugs for treating moderate to severe psoriasis with the combined biologics market estimated to be over $5 billion dollars annually.
There is only one approved oral therapy for psoriasis with annual sales estimated at over $1 billion.