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

The study evaluated the exposure-response relationship of ritlecitinib on eyebrow and eyelash regrowth in patients with severe alopecia areata, using numeric rating scales for assessment. The analysis involved longitudinal ER modeling with ordinal regression to describe the efficacy of ritlecitinib on eyebrow and eyelash hair regrowth. The models indicated that the tested doses in the phase IIb/III clinical trial are effective, with the 50 mg dose being optimal for patients with impaired eyebrow and eyelash hair. The findings support the use of ritlecitinib as a treatment for alopecia areata, with the analysis methodology applicable to other ER studies involving ordinal categorical variables.