Once-Daily Ritlecitinib Well-Tolerated for Children with Alopecia Areata

Treatment of alopecia areata with ritlecitinib 20 mg once daily for 7 days may be considered generally well tolerated among patients aged 6 to < 12 years years, according to recent findings, with no new safety signals with this medication.1

These findings were the result of new research authored by Mercedes E. Gonzalez, MD, from Pediatric Skin Research in Coral Gables, Florida. Gonzalez and her team sought to summarize the pharmacokinetic parameters of ritlecitinib therapy among pediatric patients.

The medication, an oral JAK3/TEC family kinase inhibitor, is approved in the US, Japan, the European Union, and China for the treatment of adults and adolescents with severe alopecia areata who are aged ≥ 12 years.2

“At this time, there are no systemic treatments approved for the treatment of [alopecia areata] in pediatric patients aged < 12 years,” Gonzalez and colleagues wrote. “This study was specifically designed to collect data supporting ritlecitinib dose selection for pediatric patients aged 6 to < 12 years.”1

Pharmacokinetic Parameters of Ritlecitinib Treatment for Pediatric Patients

The investigative team conducted a single-group, open-label, interventional pharmacokinetic trial, during which they evaluated ritlecitinib’s systemic exposure among children diagnosed with alopecia areata. The trial participants were aged 6 to < 12 years and would be provided with an oral dose of ritlecitinib at 20 mg on a once-per-day basis for a total of 7 consecutive days.

In terms of aims, the team’s primary endpoint for their research was the area under the concentration-time curve over 24 hours (AUC24). Secondary pharmacokinetic parameters that were evaluated and summarized by the investigators included time to reach Cmax (Tmax), volume of distribution (Vz/F), maximum concentration (Cmax), apparent clearance (CL/F), and terminal half-life (t1/2).

Additionally, the analysis involved an assessment of the drug’s safety and tolerability, with the research team monitoring trial participants for treatment-related adverse events (AEs), treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), medication and discontinuations resulting from AEs. They also reported on any shifts in laboratory values or vital signs that were deemed clinically significant.

The team administered the initial and final doses at the study site, but the remaining doses were provided to subjects at home under the supervision of caregivers. A follow-up phone consultation was then provided between the 28- and 35-day marks following the final dose. This was done to report on any delayed effects of ritlecitinib.

To allow for the investigators’ pharmacokinetic analysis, the investigative team collected blood samples on Day 7 of treatment, gathering them at several different time points. The investigative team also collected urine and plasma samples from subjects for hematology, clinical chemistry, and urinalysis.

In total, the study enrolled 15 participants and 14 were able to complete the entire course of this analysis. The team concluded that median Tmax for plasma concentrations of ritlecitinib on the 7-day mark was shown to be approximately 0.5 hours, with a mean half-life of around 1.19 hours. They also reported that geometric mean values (with % coefficient of variation) for AUC24 and Cmax were shown to be 437.5 ng·h/mL and 208.7 ng/mL (30% and 38%, respectively).

Overall, the investigators identified AEs in only 3 participants, with a total of four events. They noted specifically that there had been a single case of urticaria which resulted in permanent discontinuation of the medication. However, they also reported that there had been no severe events or SAEs. Additionally, their laboratory findings yielded no clinically significant abnormalities.

“These observed PK data will be used to inform the dose selection for pediatric phase 3 studies. Ritlecitinib was generally well tolerated among children with [alopecia areata] aged 6 to < 12 years,” they wrote. “Future studies will assess the efficacy and safety of ritlecitinib in pediatric patients with [alopecia areata].”1

References

1. Gonzalez, M.E., Browning, J., Smith, S., Plotka, A., Zhu, J.“., Parvatini, S., Huh, Y. and Wolk, R. (2025), A Phase 1, Open-Label Study of the Pharmacokinetics of Ritlecitinib in Children Aged 6–12 Years With Alopecia Areata. Pediatric Dermatology. https://doi.org/10.1111/pde.15895.

2. Pfizer Inc, “FDA Approves Pfizer's LITFULO™ (Ritlecitinib) for Adults and Adolescents With Severe Alopecia Areata,” 2023, https://www.pfizer.com/news/press-release/press-release-detail/fda-approves-pfizers-litfulotm-ritlecitinib-adults-and.