What is Ritlecitinib?

Ritlecitinib (Ritlecitinib) is a highly selective inhibitor of Janus kinase 3 (JAK3) and tyrosine kinases expressed in the hepatocellular carcinoma (TEC) kinase family. In June 2023, the U.S. Food and Drug Administration (FDA) approved ritexitinib for the treatment of severe alopecia areata in adults and adolescents aged 12 years and older. Rituxitinib is generally administered orally and is the first member of this class of drugs.

Ritexitinib covalently binds to Cys-909 of JAK3, a site where other JAK isoforms have serine residues. This makesritixitiniba highly selective and irreversibleJAK3 inhibitor. Other kinases have a cysteine u200bu200bin JAK3 at the position equivalent to Cys-909, and several of them belong to the TEC kinase family. It has been suggested that the dual activity of ritixitinib on JAK3 and the TEC kinase family blocks cytokine signaling and the cytolytic activity of T cells, both of which are related to the pathogenesis of alopecia areata.

Ritexitinibis primarily excreted in the urine and feces. Approximately 66% and 20% of radiolabeled ritixitinib were excreted in the urine and feces, respectively, and approximately 4% of the dose was excreted in the urine as unchanged drug. Ritexitinib is a new drug for the treatment of alopecia areata. It has not yet been launched in the country and has not been included in the medical insurance. Its price has not yet been learned. For specific prices and drug details, please consult a medical consultant.