Ritlecitinib is a kinase inhibitor and may block signalling of various cytokines and cytolytic activity of T cells, which is implicated in the pathogenesis of inflammatory and autoimmune diseases
- irreversibly inhibits Janus kinase 3 (JAK3) and the tyrosine kinase expressed in hepatocellular carcinoma (TEC) kinase family
- inhibits JAK3 with high selectivity over other JAK isoforms; this selectivity is the result of irreversible covalent binding to a cysteine residue at position 909 (Cys-909) in JAK3 which is replaced with a serine residue at the equivalent position in other JAK isoforms
- has been shown to inhibit signalling of immune receptors including B cell receptor (BCR) and T cell receptor (TCR), both dependent on TEC kinase family members
A review states that ritlecitinib was well tolerated in patients with alopecia areata, according to an integrated safety analysis of data from ALLEGRO-2a, ALLEGRO-2a safety study, ALLEGRO-2b/3 and ALLEGRO-LT (1):
- most adverse events (AEs) were mild in severity, self-limiting, and did not require dose interruption or permanent discontinuation of treatment
- in the placebo-controlled cohort, 345 patients were treated with ritlecitinib 50 mg once daily (i.e. the recommended dosage) for up to 24 weeks
- AEs occurring in ≥ 10% of these patients and at a higher rate than placebo included
- nasopharyngitis (23% vs 15% with placebo),
- headache (21% vs 19%),
- upper respiratory tract infection (20% vs 17%)
- acne (13% vs 10%)
NICE state:
- ritlecitinib is recommended, within its marketing authorisation, as an option for treating severe alopecia areata in people 12 years and over. Ritlecitinib is only recommended if the company provides it according to the commercial arrangement
- the NICE committee noted that "..is no standard treatment for severe alopecia areata, and access to treatment varies widely. Hair loss can cause severe psychological distress...Evidence from clinical trials shows that ritlecitinib is more effective than placebo at improving hair regrowth for up to 24 weeks..."
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