Pfizer has reported positive data from a Phase lla trial that evaluated the efficacy, safety, and tolerability of PF-06651600 and PF-06700841 in comparison with placebo to treat patients with moderate-to-severe alopecia areata (AA), an autoimmune disease characterised by hair loss.
PF-06651600 is an oral Janus kinase (JAK) 3 inhibitor, while PF-06700841 is a tyrosine kinase (TYK) 2/JAK1 inhibitor.
The Phase lla trial met its primary efficacy endpoint of improving hair regrowth on the scalp compared with baseline at week 24 as measured by the Severity of Alopecia Tool (SALT) score at 100 point scale.
The results showed that placebo-adjusted mean in SALT change from baseline scores at Week 24 were 33.6 points.
In addition, the trial met all of its secondary endpoints, while the overall, adverse event (AE) rates were found to be comparable between the treatment groups.
The most common adverse events reported during the trial were in the areas of infections, gastrointestinal and skin/subcutaneous tissue.
No cases of herpes zoster reactivation were reported in the trial.
As part of the randomised, double-blind, multicentre trial, patients were randomised in a 1:1:1 ratio to receive PF-06651600, PF-06700841 or placebo.
Pfizer Inflammation and Immunology senior vice-president and chief scientific officer Michael Vincent said: “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.”
Based on the latest data, Pfizer plans to further study PF-06651600 for use in moderate-to-severe AA, as well as rheumatoid arthritis (RA), Crohn’s disease (CD) and ulcerative colitis (UC).
The investigational inhibitor recently received breakthrough therapy designation from the US Food and Drug Administration (FDA) for AA.
Pfizer is also expected to continue to evaluate PF-06700841 for psoriasis (PsO), CD and UC.