Pfizer’s Janus kinase (JAK) inhibitors, including PF-06651600 and PF-06700841, have achieved primary efficacy endpoint of improving hair regrowth in patients with moderate to severe alopecia areata (AA) in phase 2a study.
Alopecia areata is an autoimmune disease evidenced by hair loss and often linked with profound psychological consequences.
The PF-06651600 is an oral JAK 3 inhibitor, while PF-06700841 is a tyrosine kinase (TYK) 2/JAK1 inhibitor.
According to the company, both JAK inhibitors reached the primary efficacy endpoint in improving hair regrowth on the scalp relative to baseline at week 24 as measured by the severity of alopecia tool (SALT) score.
The study investigator Dr Rodney Sinclair said: “The results seen with these JAK inhibitors are very encouraging for me as a clinician as they signal a potential new way to think about the treatment of alopecia, which may bring hope for patients with this distressing condition.”
The phase 2a randomized, double-blind and multicenter study assessed the efficacy, safety, and tolerability of PF-06651600 and PF-06700841 compared to placebo in patients with moderate to severe AA.
Pfizer’s study demonstrated that the placebo-adjusted mean in SALT change from baseline scores at week 24 were 33.6 points for PF-06651600 and 49.5 points PF-06700841, which is significant separation compared to placebo that occurred as early as week six and week four.
Recently, the PF-06651600 secured breakthrough therapy designation from FDA for alopecia areata.
It is also being advanced to the next phase of development for moderate to severe AA, as well as continues to be assessed for rheumatoid arthritis (RA), Crohn’s disease (CD) and ulcerative colitis (UC).
The PF-06700841 will also continue to be assessed for psoriasis (PsO), CD and UC.
Pfizer inflammation and immunology senior vice president and chief scientific officer Dr Michael Vincent said: “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.”