ritlecitinib

Modality

small molecule (kinase inhibitor)

Mechanism

12.1 Mechanism of Action LITFULO is a kinase inhibitor. Ritlecitinib irreversibly inhibits Janus kinase 3 (JAK3) and the tyrosine kinase expressed in hepatocellular carcinoma (TEC) kinase family by blocking the adenosine triphosphate (ATP) binding site. In cellular settings, ritlecitinib inhibits cytokine induced STAT phosphorylation mediated by JAK3-dependent receptors. Additionally, ritlecitinib inhibits signaling of immune receptors dependent on TEC kinase family members. The relevance of inhibition of specific JAK or TEC family enzymes to therapeutic effectiveness is not currently known.

Targets

Tyrosine-protein kinase JAK3, Tyrosine-protein kinase Tec, Tyrosine-protein kinase ITK/TSK, Tyrosine-protein kinase TXK, Tyrosine-protein kinase BTK, Cytoplasmic tyrosine-protein kinase BMX

Storage

—

Approved

alopecia areata — FDA

In trial

alopecia areata, vitiligo, hidradenitis suppurativa

Black-box warnings

serious infections; mortality (all-cause, RA pts ≥50 with CV risk); malignancy; MACE (non-fatal MI / stroke); thrombosis (DVT, PE, arterial)

Source

DailyMed label

Last verified

2026-04-19

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