Ivarmacitinib (SHR0302) is a potent and orally active inhibitor of JAK family, particularly JAK1. Ivarmacitinib demonstrates more than 10-fold selectivity for JAK1 over JAK2, 77-fold over JAK3, and 420-fold over Tyk2. Ivarmacitinib also exhibits anti-proliferative and anti-inflammatory effects.