Pfizer Inc (NYSE:PFE) a US-based pharmaceutical company announced on Saturday results from its Phase 2a study of PF-06651600, an oral Janus kinase (JAK) 3 inhibitor, and PF-06700841, a tyrosine kinase (TYK) 2/JAK1 inhibitor, compared to placebo, in patients with moderate to severe alopecia areata (AA), an autoimmune disease characterised by hair loss and often associated with profound psychological consequences.

Both JAK inhibitors met the primary efficacy endpoint in improving hair regrowth on the scalp relative to baseline at week 24 (33.6 points and 49.5 points for JAK3 and TYK2/JAK1, respectively) as measured by the Severity of Alopecia Tool (SALT) score (100 point scale). The findings were presented during a Late-Breaking News session at the 27th European Academy of Dermatology and Venereology (EADV) Congress in Paris, France.

'We are pleased with these results and excited by the potential of kinase inhibition as a new therapeutic target for patients living with alopecia areata. This is the first well-controlled study of oral JAK inhibitors in alopecia areata, helping enhance our understanding of this disease with significant unmet need and advance the science of kinase inhibition,' said Michael Vincent, MD, PhD, senior vice president and chief scientific officer, Pfizer Inflammation and Immunology.

Based on the totality of the data and the emerging clinical profiles, the investigational JAK3 inhibitor, which was recently granted Breakthrough Therapy designation from FDA for alopecia areata, is advancing to the next phase of development for moderate to severe AA and will continue to be evaluated for rheumatoid arthritis (RA), Crohn's disease (CD) and ulcerative colitis (UC). PF-06700841 will continue to be evaluated for psoriasis (PsO), CD and UC.