Ruxolitinib
JAKAFI
What it isJAK1/JAK2 inhibitor; myelofibrosis, polycythemia vera, and graft-versus-host disease.
Why this oneUnlike conventional cytoreductive drugs, it rapidly reduces splenomegaly and constitutional symptoms in myelofibrosis.
What limits itMyelosuppression makes platelets and hemoglobin central to dosing. Abrupt withdrawal can provoke a cytokine-rebound syndrome.
FDA-approved for
- myelofibrosis (2011)
- polycythemia vera, graft-versus-host disease
Off-label
- steroid-refractory graft-versus-host disease beyond label
- vitiligo (topical form is approved)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Myelofibrosis | Adults | Platelet-based: >200 x10^9/L → 20 mg BID (XR 44 mg QD); 100–200 → 15 mg BID (XR 33 mg QD); 50–<100 → 5 mg BID (XR 11 mg QD) | titrate by safety/efficacy | 25 mg BID |
| Polycythemia vera | Adults | 10 mg BID (XR 22 mg QD) | titrate by safety/efficacy | — |
| Acute graft-versus-host disease | Adults and pediatric patients | 5 mg BID (XR 11 mg QD) | titrate by safety/efficacy | — |
| Chronic graft-versus-host disease | Adults and pediatric patients | 10 mg BID (XR 22 mg QD) | titrate by safety/efficacy | — |
Renal Reduce starting dose or avoid treatment per renal-function recommendations (indication/platelet-based).
Hepatic Reduce starting dose or avoid treatment per hepatic recommendations.
Doses are individualized and modified for thrombocytopenia/neutropenia per label tables.
Instructions
- JAKAFI (IR) taken twice daily; JAKAFI XR taken once daily; XR tablets swallowed whole
- Perform CBC before starting and every 2–4 weeks until doses are stabilized
- Do not interrupt/discontinue abruptly — use supportive care and consider resuming to avoid symptom exacerbation
- Screen for infections (TB, HBV, HSV, herpes zoster) before starting
Cautions
- Thrombocytopenia, anemia, neutropenia
- Serious infections (bacterial, mycobacterial/TB, fungal, viral; HBV reactivation)
- Symptom exacerbation on interruption/discontinuation
- Non-melanoma skin cancer
- Lipid elevations
- MACE, thrombosis, and secondary malignancies (JAK inhibitor class)
Adverse reactions
- Thrombocytopenia
- Anemia
- Neutropenia
- Bruising
- Dizziness
- Headache
- Diarrhea
- Infections
- Edema
Pregnancy No human data; animal studies show adverse developmental outcomes at maternally toxic doses.
Lactation Advise not to breastfeed during treatment.
NO BOXED WARNINGS
Principal riskMyelosuppression; cytokine rebound on abrupt withdrawal
Cost, est. cash$5,000–$30,000+/month or cycle
Generic entry2041 est.
Classes and tags
Clinical profile
Legacy pregnancy categoryD
Defining liabilityMyelosuppression and agent-specific hepatic, cardiac, pulmonary, neurologic or reproductive toxicity require oncology monitoring.
Mechanism of action: Ruxolitinib ballicule
