Ritlecitinib: an investigational drug for the treatment of moderate to severe alopecia areata

Alopecia areata (AA) is an inflammatory and autoimmune form of hair loss, which can present with one patch of hair loss, but in more extreme cases can lead to total body hair loss. There are limited therapeutic options and no cure, but medication can sometimes induce sustained remission. Disease control cannot be guaranteed; even those who regrow all hair on treatment can experience relapse. There are no FDA approved systemic treatments; therefore, an unmet need for safe, and effective treatments exists. Few treatments have been evaluated by randomized controlled trials. Case reports and series indicate oral Janus Kinase (JAK) inhibitors as a potential therapy. Ritlecitinib is a novel oral JAK3-selective inhibitor being investigated as an AA treatment.This article introduces ritlecitinib as treatment for AA and considers the mechanism of action, pharmacodynamics, pharmacokinetics, clinical efficacy, and safety [reporting data from a 24-week, phase 2a double-blinded placebo-controlled trial of ritlecitinib in patients with AA who have more than 50% scalp hair loss].Ritlecitinib offers a novel mode of action, rapid onset, and the capacity for a superior safety profile over other JAK inhibitors. If approved, ritlecitinib will be widely prescribed by physicians overseeing the more severe AA patients for the foreseeable future. As JAK inhibitors regulate the hair growth cycle and have anti-inflammatory effects, the implementation of ritlecitinib in hair loss disorders other than AA, may prove beneficial.