Mechanism of action

Upadacitinib selectively inhibits JAK1, a key intracellular tyrosine kinase involved in the JAK‑STAT signaling pathway.
By blocking JAK1, upadacitinib:

Prevents phosphorylation and activation of STAT transcription factors
Inhibits signaling from multiple pro‑inflammatory cytokines (e.g., IL‑6, IL‑2, IL‑12, IL‑23, interferons)

Indication

Approved indications (FDA / EMA):

Rheumatoid arthritis (moderate to severe)
Psoriatic arthritis
Ankylosing spondylitis
Non‑radiographic axial spondyloarthritis
Atopic dermatitis (moderate to severe)
Ulcerative colitis
Crohn’s disease
Giant cell arteritis
Polyarticular juvenile idiopathic arthritis