Pacritinib

What it is and how it works

Mechanism of Action Pacritinib is an oral kinase inhibitor with activity against wild type Janus associated kinase 2 (JAK2), mutant JAK2V617F, FMS-like tyrosine kinase 3 (FLT3), and interleukin 1 receptor associated kinase-1 (IRAK1) which contribute to signaling of a number of cytokines and growth factors that are important for hematopoiesis and immune function. Pacritinib is also an inhibitor of activin A receptor, type 1/activin receptor like-kinase 2 (ACVR1/ALK2). MF is often associated with dysregulated JAK2 signaling. At clinically relevant concentrations, pacritinib does not inhibit JAK1. Pacritinib has higher inhibitory activity for JAK2 compared to JAK3 and tyrosine kinase 2 (TYK2).

Mechanism class: Tyrosine Kinase Inhibitors · Janus Kinase Inhibitors · Cytochrome P450 1A2 Inhibitors

Indications

is indicated for the treatment of adults with intermediate or high-risk primary or secondary (post-polycythemia vera or post-essential thrombocythemia) myelofibrosis (MF) with a platelet count below 50 × 10 9 /L. This indication is approved under accelerated approval based on spleen volume reduction . Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s). VONJO is a kinase inhibitor indicated for the treatment of adults with intermediate or high-risk primary or secondary (post-polycythemia vera or post-essential thrombocythemia) myelofibrosis with a platelet count below 50 × 10 9 /L . This indication is approved under accelerated approval based on spleen volume reduction. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).

Dosage and administration (summary)

Recommended dosage is 200 mg orally twice daily . May be taken with or without food . Recommended Dosage The recommended dosage of VONJO is 200 mg orally twice daily. VONJO may be taken with or without food. Swallow capsules whole. Do not open, break, or chew capsules. Patients who are on treatment with other kinase inhibitors before the initiation of VONJO must taper or discontinue according to the prescribing information for that drug. Monitoring for Safety Perform a complete blood count (CBC.

Contraindications

is contraindicated in patients concomitantly using strong CYP3A4 inhibitors or inducers as these medications can significantly alter exposure to pacritinib, which may increase the risk of adverse reactions or impair efficacy . Concomitant use of strong CYP3A4 inhibitors or inducers

Warnings and precautions

Hemorrhage: Avoid use in patients with active bleeding and hold VONJO prior to any planned surgical procedures. May require dose interruption, dose reduction or permanent discontinuation depending on severity . Diarrhea: Manage significant diarrhea with anti-diarrheals, dose reduction, or dose interruption . Thrombocytopenia: Manage by dose reduction or interruption . Prolonged QT Interval: Avoid use in patients with baseline QTc >480 msec. Interrupt and reduce VONJO dosage in patients who have a QTcF >500 msec. Correct hypokalemia prior to and during VONJO administration .

Pregnancy

Pregnancy Risk Summary There are no available data on VONJO use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes.

Storage and supply

Storage Store at room temperature, below 30°C (86°F). Keep the bottle tightly closed and protect from light. Store in original package. Dispense in original package or in a light-resistant container.

Source: Pacritinib (Vonjo) — US FDA prescribing information, 2026-07-30, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.