Population Exposure–Response Analysis of the Effect of Ritlecitinib on Eyebrow and Eyelash Assessment in Patients with Alopecia Areata

The study evaluated the effects of ritlecitinib on eyebrow and eyelash regrowth in patients with alopecia areata, involving 594 individuals for eyebrow assessment and 535 for eyelash assessment. It found that higher doses of ritlecitinib led to greater efficacy, with a 200 mg loading dose showing earlier efficacy in eyebrow scores but not in eyelash scores. The study highlighted demographic factors, noting that Asian patients showed higher efficacy and females had less severe eyelash loss than males. The analysis supported a 50 mg daily dose without a loading dose for effective treatment, as higher doses did not significantly increase efficacy. The use of ordinal regression models improved data fit, capturing the ordinal nature of the assessment scores.