Ruxolitinib

What it is and how it works

Mechanism of Action Ruxolitinib, a kinase inhibitor, inhibits Janus Associated Kinases (JAKs), JAK1 and JAK2, which mediate the signaling of a number of cytokines and growth factors that are important for hematopoiesis and immune function. JAK signaling involves recruitment of STATs (signal transducers and activators of transcription) to cytokine receptors, activation, and subsequent localization of STATs to the nucleus leading to modulation of gene expression. MF and PV are myeloproliferative neoplasms (MPNs) known to be associated with dysregulated JAK1 and JAK2 signaling.

Mechanism class: Janus Kinase Inhibitors

Indications

is a kinase inhibitor indicated for treatment of: intermediate or high-risk myelofibrosis, including primary myelofibrosis, post-polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis in adults. polycythemia vera in adults who have had an inadequate response to or are intolerant of hydroxyurea. steroid-refractory acute graft-versus-host disease in adult and pediatric patients 12 years and older. chronic graft-versus-host disease after failure of one or two lines of systemic therapy in adult and pediatric patients 12 years and older. Myelofibrosis JAKAFI/JAKAFI XR is indicated for treatment of intermediate or high-risk myelofibrosis (MF), including primary MF, post-polycythemia vera MF, and post-essential thrombocythemia MF in adults. Polycythemia Vera JAKAFI/JAKAFI XR is indicated for treatment of polycythemia vera (PV) in adults who have had an inadequate response to or are intolerant of hydroxyurea.

Dosage and administration (summary)

Doses should be individualized based on safety and efficacy. Starting doses per indication are noted below. Myelofibrosis The starting dose of JAKAFI/JAKAFI XR is based on patient’s baseline platelet count: • Greater than 200 × 10 9 /L: JAKAFI 20 mg given orally twice daily or JAKAFI XR 44 mg given orally once daily. • 100 x 10 9 /L to 200 x 10 9 /L: JAKAFI 15 mg given orally twice daily or JAKAFI XR 33 mg given orally once daily. • 50 x 10 9 /L to less than 100 x 10 9 /L: JAKAFI 5 mg given orally twice daily or JAKAFI XR 11 mg given orally once daily. Polycythemia Vera The starting dose of JAKAFI is 10 mg given orally twice daily or JAKAFI XR 22 mg given orally once daily.

Contraindications

None. None.

Warnings and precautions

Thrombocytopenia, Anemia, and Neutropenia: Manage by dose reduction or interruption, or transfusion. Risk of Infection: Assess patients for signs and symptoms of infection and initiate appropriate treatment promptly. Serious infections should have resolved before starting therapy with JAKAFI/JAKAFI XR. Symptom Exacerbation Following Interruption or Discontinuation: Manage with supportive care and consider resuming treatment with JAKAFI/JAKAFI XR. Risk of Non-Melanoma Skin Cancer: Perform periodic skin examinations.

Pregnancy

Pregnancy Risk Summary When pregnant rats and rabbits were administered ruxolitinib during the period of organogenesis adverse developmental outcomes occurred at doses associated with maternal toxicity (see Data) . There are no studies with the use of JAKAFI/JAKAFI XR in pregnant women to inform drug-associated risks.

Storage and supply

(ruxolitinib) tablets are available as follows: JAKAFI Trade Presentations NDC Number Strength Description Tablets per Bottle 50881-005-60 5 mg Round tablet with “INCY” on one side and “5” on the other 60 50881-010-60 10 mg Round tablet with “INCY” on one side and “10” on the other 60 50881-015-60 15 mg Oval tablet with “INCY” on one side and “15” …

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