Ritlecitinib Sustains Hair Regrowth in Alopecia Areata Through 3 Years

Nearly two-thirds of patients with severe alopecia areata who stayed on ritlecitinib for 3 years had regrown at least 80% of their scalp hair, according to a long-term extension of the pivotal ALLEGRO trials published in the American Journal of Clinical Dermatology.¹

FDA Approval Rested on Just 48 Weeks of Trial Data

In June 2023, the FDA approved ritlecitinib, an oral inhibitor of Janus kinase 3 and the TEC family of kinases, for patients 12 years and older with alopecia areata, based on 48-week results from the phase 2b/3 ALLEGRO (NCT03732807) trial, in which 718 patients with 50% or more scalp hair loss were enrolled across 118 sites in 18 countries and 23% of those on the drug reached at least 80% scalp coverage by 6 months, compared with 1.6% on placebo.²

Alopecia areata, an autoimmune disease marked by patchy or extensive hair loss, often follows a chronic, relapsing course, so clinicians needed to know whether this early benefit would hold up or erode over years of continuous use.

The researchers analyzed patients 12 years and older with alopecia areata and at least 50% scalp hair loss who received ritlecitinib 50 mg once daily in ALLEGRO-2b/3 and then rolled over onto the same dose in the ongoing, open-label ALLEGRO-LT (NCT04006457) extension study, reporting both observed outcomes and a more conservative last-observation-carried-forward (LOCF) analysis through a data cutoff of June 25, 2024.¹

The analysis included 191 patients, 14.1% of them adolescents, with a mean baseline Severity of Alopecia Tool (SALT) score of 83.3 and a median alopecia areata diagnosis of 6.9 years earlier. By the cutoff, 14.1% of patients were still enrolled in the extension, and 53.4% had discontinued, with dropout more common among those who started with more extensive hair loss.

Complete Scalp Regrowth Tripled Between Year 1 and Year 3

At 3 years, 65.1% of patients by observed data (47.1% by LOCF) had a SALT score of 20 or less, indicating 80% or more scalp coverage, and 52.3% (36.7% by LOCF) reached a SALT score of 10 or less. Complete scalp hair regrowth, a SALT score of 0, climbed from 11.0% at 1 year to 20.0% at 2 years and 31.2% at 3 years by observed data (22.5% by LOCF).

Durability was strong among early responders: of patients who had a SALT score of 20 or less at 1 year, 88.3% to 89.6% maintained that response at 3 years, though 8 of those who maintained the response briefly lost it (SALT greater than 20) at some point in between, with several regaining the response on continued treatment. Female sex, White race, and less extensive and shorter-duration hair loss at baseline were independently associated with a higher likelihood of response.

Adverse events occurred in 97.4% of the 191 patients, and serious adverse events occurred in 6.8%, with no new deaths or major cardiovascular events reported beyond those in earlier analyses. The most common adverse events were SARS-CoV-2 test positivity, headache, and nasopharyngitis. Herpes zoster occurred in 5.2% of patients, and malignancies other than nonmelanoma skin cancer occurred in 1.6%.

“Efficacy with ritlecitinib was maintained for up to 3 years, and the safety profile remained consistent,” the researchers wrote.

Pfizer, which markets ritlecitinib as Litfulo, sponsored the study and funded medical writing support; several authors reported consulting or investigator relationships with Pfizer and other drugmakers, and 6 authors are Pfizer employees who may hold company stock.

Because ALLEGRO-LT is open-label and patients who tolerate or respond to treatment are more likely to remain enrolled, observed response rates are conditional on staying in the study, and the LOCF analysis is more conservative but does not fully correct for that attrition. Five adolescents were withdrawn under the extension's protocol-specified efficacy criteria and were counted as nonresponders under LOCF, which may understate pediatric response.

References

1. Senna M, Soung J, Figueras I, et al. Long-term efficacy and safety of ritlecitinib in adults and adolescents with alopecia areata: 3-year results from the ALLEGRO phase 2b/3 and ALLEGRO-LT phase 3 clinical studies. Am J Clin Dermatol. 2026;27(5):1091-1105. doi:10.1007/s40257-026-01029-y
2. FDA approves ritlecitinib for alopecia areata for adolescents, adults. Drug Topics^®️. June 23, 2023. Accessed October 12, 2026. https://www.drugtopics.com/view/fda-approves-ritlecitinib-for-alopecia-areata-for-adolescents-adults