Abrocitinib (PF-04965842)

Abrocitinib is an oral small-molecule inhibitor of Janus kinase 1 (JAK1). Janus kinases are intracellular enzymes involved in transduction pathways that regulate hematopoiesis and immune cell function. The Janus kinase (JAK)–signal transducer and activator of transcription (STAT) signalling pathway plays a central role in the pathogenesis of a variety of autoimmune and inflammatory diseases, including atopic dermatitis, a chronic inflammatory skin disease with complex pathogenesis. Atopic dermatitis is characterized by epidermal hyperplasia, skin barrier dysfunction, and the aberrant activation of immune cells. Patients with moderate-to-severe atopic dermatitis report reduced quality of life and often face limited treatment options. JAK inhibitors recently attracted more attention as potential treatments for inflammatory disorders, as JAK inhibition is associated with rapid and sustained anti-inflammatory efects. Abrocitinib was approved by the European Commission on December 10, 2021, for the treatment of moderate-to-severe atopic dermatitis (AD) in adults who are candidates for systemic therapy. On January 14, 2022, the FDA approved abrocitinib for the treatment of refractory, moderate-to-severe AD in adults whose disease is not adequately controlled with other systemic drug products, including biologics, or when the use of those therapies is inadvisable. Health Canada also approved the use of abrocitinib in pediatric patients 12 years and older.