Momelotinib

What it is and how it works

Mechanism of Action Momelotinib is an inhibitor of wild type Janus Kinase 1 and 2 (JAK1/JAK2) and mutant JAK2 V617F , which contribute to signaling of a number of cytokines and growth factors that are important for hematopoiesis and immune function. Momelotinib and its major human circulating metabolite, M21, have higher inhibitory activity for JAK2 compared to JAK3 and tyrosine kinase 2 (TYK2). Momelotinib and M21 additionally inhibit activin A receptor type 1 (ACVR1), also known as activin receptor like kinase 2 (ALK2), which produces subsequent inhibition of liver hepcidin expression and increased iron availability resulting in increased red blood cell production.

Indications

is indicated for the treatment of intermediate or high‑risk myelofibrosis (MF), including primary MF or secondary MF [post‑polycythemia vera (PV) and post‑essential thrombocythemia (ET)], in adults with anemia. OJJAARA is a kinase inhibitor indicated for the treatment of intermediate or high‑risk myelofibrosis (MF), including primary MF or secondary MF [post‑polycythemia vera (PV) and post‑essential thrombocythemia (ET)], in adults with anemia.

Dosage and administration (summary)

• Recommended dosage: 200 mg orally once daily with or without food. • Severe hepatic impairment (Child-Pugh Class C): Reduce the starting dose to 150 mg orally once daily. Recommended Dosage The recommended dosage of OJJAARA is 200 mg orally once daily. OJJAARA may be taken with or without food. Swallow OJJAARA tablets whole. Do not cut, crush, or chew tablets. If a dose of OJJAARA is missed, the next scheduled dose should be taken the following day.

Contraindications

None. None.

Warnings and precautions

• Risk of Infections: Do not initiate OJJAARA in patients with an active infection. Monitor for signs and symptoms of infection, including reactivation of hepatitis B, and initiate appropriate treatment promptly. • Thrombocytopenia and Neutropenia: Manage by dose reduction or interruption. • Hepatotoxicity: Obtain liver tests before initiation of and periodically throughout treatment with OJJAARA. • Severe Cutaneous Adverse Reactions (SCARs): Monitor for signs and symptoms, and interrupt OJJAARA until etiology of reaction has been determined.

Pregnancy

Pregnancy Risk Summary Available data on the use of OJJAARA in pregnant women are insufficient to determine whether there is a drug‑associated risk for major birth defects or miscarriage.

Storage and supply

(momelotinib) tablets are available as follows: Table 6: OJJAARA Presentations NDC Number Strength Description Tablets per Bottle NDC 81864-103-30 100 mg Round‑shaped brown film‑coated tablet with “ M ” on one side and “100” on the other side.

Source: Momelotinib (Ojjaara) — US FDA prescribing information, 2026-07-20, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.