Medical Editor: John P. Cunha, DO, FACOEP
What Is Jakafi?
Jakafi (ruxolitinib) is a kinase inhibitor used in the treatment of intermediate or high-risk types of myelofibrosis, a potentially life-threatening blood cancer
What Are Side Effects of Jakafi?
Jakafi may cause serious side effects including:
- hives,
- difficulty breathing,
- swelling of your face, lips, tongue, or throat,
- blisters or painful skin rash,
- changes in the size, shape, or color of a mole or skin lesion,
- problems with speech, thought, vision, or muscle movement,
- nausea,
- vomiting,
- weakness,
- general ill feeling,
- pain or burning when you urinate,
- fever,
- chills,
- tiredness,
- mouth sores,
- skin sores,
- easy bruising,
- unusual bleeding,
- pale skin,
- cold hands and feet,
- lightheadedness,
- shortness of breath,
- cough,
- night sweats,
- loss of appetite,
- weight loss, and
- feeling very tired
Get medical help right away, if you have any of the symptoms listed above.
Common side effects of Jakafi include:
- bruising,
- dizziness,
- headache,
- urinary tract infections,
- weight gain,
- bloating,
- gas,
- low blood platelet levels (thrombocytopenia),
- anemia,
- fatigue,
- diarrhea,
- shortness of breath, and
- nausea.
Some side effects of Jakafi may be similar to the symptoms of myelofibrosis. Tell your doctor if you have serious side effects of Jakafi including:
- pale skin,
- lightheadedness,
- shortness of breath,
- rapid heart rate,
- trouble concentrating,
- easy bruising,
- unusual bleeding (nose, mouth, vagina, or rectum),
- purple or red pinpoint spots under your skin,
- fever,
- chills,
- body aches,
- flu symptoms,
- vomiting,
- sores in your mouth and throat,
- pain or burning when you urinate, or
- blisters or painful skin rash.
Seek medical care or call 911 at once if you have the following serious side effects:
- Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
- Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheadedness, or passing out;
- Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.
This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.
Dosage for Jakafi
The starting dose of Jakafi is 20 mg given orally twice daily for patients with a platelet count greater than 200 X 109/L, and 15 mg twice daily for patients with a platelet count between 100 X 109/L and 200 X 109/L. Jakafi is available in the following forms and strengths: 5, 10, 15, 20, and 25 mg tablets.
What Drugs, Substances, or Supplements Interact with Jakafi?
Jakafi may interact with conivaptan, imatinib, isoniazid, nefazodone, antibiotics, antifungal medications, heart or blood pressure medications, or HIV/AIDS medicines. Tell your doctor all medications and supplements you use.
Jakafi During Pregnancy and Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant while using Jakafi; it is unknown if it will harm a fetus. It is unknown if Jakafi passes into breast milk or if it could harm a nursing baby. Breastfeeding while using Jakafi is not recommended.
Additional Information
Our Jakafi Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

SLIDESHOW
Signs of Cancer in Men: Could it Be Cancer? See SlideshowGet emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Some side effects may be similar to the symptoms of myelofibrosis. Call your doctor at once if you have:
- blisters or painful skin rash;
- changes in the size, shape, or color of a mole or skin lesion;
- problems with speech, thought, vision, or muscle movement (these symptoms may start gradually and get worse quickly);
- nausea, vomiting, weakness, general ill feeling;
- pain or burning when you urinate;
- low blood cell counts--fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath; or
- signs of tuberculosis: fever, cough, night sweats, loss of appetite, weight loss, and feeling very tired.
Common side effects may include:
- low blood cell counts;
- fluid retention;
- diarrhea;
- dizziness; or
- headache.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

QUESTION
What is leukemia? See AnswerSIDE EFFECTS
The following clinically significant adverse reactions are discussed in greater detail in other sections of the labeling:
- Thrombocytopenia, Anemia and Neutropenia [see WARNINGS AND PRECAUTIONS]
- Risk of Infection [see WARNINGS AND PRECAUTIONS]
- Symptom Exacerbation Following Interruption or Discontinuation of Treatment with Jakafi [see WARNINGS AND PRECAUTIONS]
- Non-Melanoma Skin Cancer [see WARNINGS AND PRECAUTIONS]
- Lipid Elevations [see WARNINGS AND PRECAUTIONS]
- Major Adverse Cardiovascular Events (MACE) [see WARNINGS AND PRECAUTIONS]
- Thrombosis [see WARNINGS AND PRECAUTIONS]
- Secondary Malignancies [see WARNINGS AND PRECAUTIONS]
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Myelofibrosis
The safety of Jakafi was assessed in 617 patients in six clinical studies with a median duration of follow-up of 10.9 months, including 301 patients with MF in two Phase 3 studies.
In these two Phase 3 studies, patients had a median duration of exposure to Jakafi of 9.5 months (range 0.5 to 17 months), with 89% of patients treated for more than 6 months and 25% treated for more than 12 months. One hundred and eleven (111) patients started treatment at 15 mg twice daily and 190 patients started at 20 mg twice daily. In patients starting treatment with 15 mg twice daily (pretreatment platelet counts of 100 to 200 x 109/L) and 20 mg twice daily (pretreatment platelet counts greater than 200 x 109/L), 65% and 25% of patients, respectively, required a dose reduction below the starting dose within the first 8 weeks of therapy.
In a double-blind, randomized, placebo-controlled study of Jakafi, among the 155 patients treated with Jakafi, the most frequent adverse reactions were thrombocytopenia and anemia [see Table 13]. Thrombocytopenia, anemia and neutropenia are dose-related effects. The three most frequent nonhematologic adverse reactions were bruising, dizziness and headache [see Table 12].
Discontinuation for adverse events, regardless of causality, was observed in 11% of patients treated with Jakafi and 11% of patients treated with placebo.
Table 12 presents the most common nonhematologic adverse reactions occurring in patients who received Jakafi in the double-blind, placebo-controlled study during randomized treatment.
Table 12: Myelofibrosis: Nonhematologic Adverse Reactions Occurring in Patients on Jakafi in the Double-blind, Placebo-controlled Study During Randomized Treatment
Adverse Reactions | Jakafi (N=155) |
Placebo (N=151) |
||||
All Gradesa (%) | Grade 3 (%) | Grade 4 (%) | All Grades (%) | Grade 3 (%) | Grade 4 (%) | |
Bruisingb | 23 | < 1 | 0 | 15 | 0 | 0 |
Dizzinessc | 18 | < 1 | 0 | 7 | 0 | 0 |
Headache | 15 | 0 | 0 | 5 | 0 | 0 |
Urinary Tract Infectionsd | 9 | 0 | 0 | 5 | < 1 | < 1 |
Weight Gaine | 7 | < 1 | 0 | 1 | < 1 | 0 |
Flatulence | 5 | 0 | 0 | < 1 | 0 | 0 |
Herpes Zosterf | 2 | 0 | 0 | < 1 | 0 | 0 |
a National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 3.0 b includes contusion, ecchymosis, hematoma, injection site hematoma, periorbital hematoma, vessel puncture site hematoma, increased tendency to bruise, petechiae, purpura c includes dizziness, postural dizziness, vertigo, balance disorder, Meniere's Disease, labyrinthitis d includes urinary tract infection, cystitis, urosepsis, urinary tract infection bacterial, kidney infection, pyuria, bacteria urine, bacteria urine identified, nitrite urine present e includes weight increased, abnormal weight gain f includes herpes zoster and post-herpetic neuralgia |
Description Of Selected Adverse Reactions
Anemia
In the two Phase 3 clinical studies, median time to onset of first CTCAE Grade 2 or higher anemia was approximately 6 weeks. One patient (< 1%) discontinued treatment because of anemia. In patients receiving Jakafi, mean decreases in hemoglobin reached a nadir of approximately 1.5 to 2.0 g/dL below baseline after 8 to 12 weeks of therapy and then gradually recovered to reach a new steady state that was approximately 1.0 g/dL below baseline. This pattern was observed in patients regardless of whether they had received transfusions during therapy.
In the randomized, placebo-controlled study, 60% of patients treated with Jakafi and 38% of patients receiving placebo received red blood cell transfusions during randomized treatment. Among transfused patients, the median number of units transfused per month was 1.2 in patients treated with Jakafi and 1.7 in placebo treated patients.
Thrombocytopenia
In the two Phase 3 clinical studies, in patients who developed Grade 3 or 4 thrombocytopenia, the median time to onset was approximately 8 weeks. Thrombocytopenia was generally reversible with dose reduction or dose interruption. The median time to recovery of platelet counts above 50 x 109/L was 14 days. Platelet transfusions were administered to 5% of patients receiving Jakafi and to 4% of patients receiving control regimens. Discontinuation of treatment because of thrombocytopenia occurred in < 1% of patients receiving Jakafi and < 1% of patients receiving control regimens. Patients with a platelet count of 100 x 109/L to 200 x 109/L before starting Jakafi had a higher frequency of Grade 3 or 4 thrombocytopenia compared to patients with a platelet count greater than 200 x 109/L (17% versus 7%).
Neutropenia
In the two Phase 3 clinical studies, 1% of patients reduced or stopped Jakafi because of neutropenia.
Table 13 provides the frequency and severity of clinical hematology abnormalities reported for patients receiving treatment with Jakafi or placebo in the placebo-controlled study.
Table 13: Myelofibrosis: Worst Hematology Laboratory Abnormalities in the Placebo-Controlled Studya
Laboratory Parameter | Jakafi (N=155) |
Placebo (N=151) |
||||
All Gradesb (%) | Grade 3 (%) | Grade 4 (%) | All Grades (%) | Grade 3 (%) | Grade 4 (%) | |
Thrombocytopenia | 70 | 9 | 4 | 31 | 1 | 0 |
Anemia | 96 | 34 | 11 | 87 | 16 | 3 |
Neutropenia | 19 | 5 | 2 | 4 | < 1 | 1 |
a Presented values are worst Grade values regardless of baseline b National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0 |
Additional Data From The Placebo-Controlled Study
- 25% of patients treated with Jakafi and 7% of patients treated with placebo developed newly occurring or worsening Grade 1 abnormalities in alanine transaminase (ALT). The incidence of greater than or equal to Grade 2 elevations was 2% for Jakafi with 1% Grade 3 and no Grade 4 ALT elevations.
- 17% of patients treated with Jakafi and 6% of patients treated with placebo developed newly occurring or worsening Grade 1 abnormalities in aspartate transaminase (AST). The incidence of Grade 2 AST elevations was < 1% for Jakafi with no Grade 3 or 4 AST elevations.
- 17% of patients treated with Jakafi and < 1% of patients treated with placebo developed newly occurring or worsening Grade 1 elevations in cholesterol. The incidence of Grade 2 cholesterol elevations was < 1% for Jakafi with no Grade 3 or 4 cholesterol elevations.
Polycythemia Vera
In a randomized, open-label, active-controlled study, 110 patients with PV resistant to or intolerant of hydroxyurea received Jakafi and 111 patients received best available therapy [see Clinical Studies]. The most frequent adverse reaction was anemia. Discontinuation for adverse events, regardless of causality, was observed in 4% of patients treated with Jakafi. Table 14 presents the most frequent nonhematologic adverse reactions occurring up to Week 32.
Table 14: Polycythemia Vera: Nonhematologic Adverse Reactions Occurring in ≥ 5% of Patients on Jakafi in the Open-Label, Active-controlled Study up to Week 32 of Randomized Treatment
Adverse Reactions | Jakafi (N=110) |
Best Available Therapy (N=111) |
||
All Gradesa (%) | Grade 3-4 (%) | All Grades (%) | Grade 3-4 (%) | |
Diarrhea | 15 | 0 | 7 | < 1 |
Dizzinessb | 15 | 0 | 13 | 0 |
Dyspneac | 13 | 3 | 4 | 0 |
Muscle Spasms | 12 | < 1 | 5 | 0 |
Constipation | 8 | 0 | 3 | 0 |
Herpes Zosterd | 6 | < 1 | 0 | 0 |
Nausea | 6 | 0 | 4 | 0 |
Weight Gaine | 6 | 0 | < 1 | 0 |
Urinary Tract Infectionsf | 6 | 0 | 3 | 0 |
Hypertension | 5 | < 1 | 3 | < 1 |
a National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 3.0 b includes dizziness and vertigo c includes dyspnea and dyspnea exertional d includes herpes zoster and post-herpetic neuralgia e includes weight increased and abnormal weight gain f includes urinary tract infection and cystitis |
Clinically relevant laboratory abnormalities are shown in Table 15.
Table 15: Polycythemia Vera: Selected Laboratory Abnormalities in the Open-Label, Active-controlled Study up to Week 32 of Randomized Treatmenta
Laboratory Parameter | Jakafi (N=110) |
Best Available Therapy (N=111) |
||||
All Gradesb (%) | Grade 3m(%) | Grade 4 (%) | All Grades (%) | Grade 3 (%) | Grade 4 (%) | |
Hematology | ||||||
Anemia | 72 | < 1 | < 1 | 58 | 0 | 0 |
Thrombocytopenia | 27 | 5 | < 1 | 24 | 3 | < 1 |
Neutropenia | 3 | 0 | < 1 | 10 | < 1 | 0 |
Chemistry | ||||||
Hypercholesterolemia | 35 | 0 | 0 | 8 | 0 | 0 |
Elevated ALT | 25 | < 1 | 0 | 16 | 0 | 0 |
Elevated AST | 23 | 0 | 0 | 23 | < 1 | 0 |
Hypertriglyceridemia | 15 | 0 | 0 | 13 | 0 | 0 |
a Presented values are worst Grade values regardless of baseline b National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0 |
Acute Graft-Versus-Host Disease
In a single-arm, open-label study, 71 adults (ages 18-73 years) were treated with Jakafi for aGVHD failing treatment with steroids with or without other immunosuppressive drugs [see Clinical Studies]. The median duration of treatment with Jakafi was 46 days (range, 4-382 days).
There were no fatal adverse reactions to Jakafi. An adverse reaction resulting in treatment discontinuation occurred in 31% of patients. The most common adverse reaction leading to treatment discontinuation was infection (10%). Table 16 shows the adverse reactions other than laboratory abnormalities.
Table 16: Acute Graft-Versus-Host Disease: Nonhematologic Adverse Reactions Occurring in ≥ 15% of Patients in the Open-Label, Single-Cohort Study
Adverse Reactionsa | Jakafi (N=71) |
|
All Gradesb (%) | Grade 3-4 (%) | |
Infections (pathogen not specified) | 55 | 41 |
Edema | 51 | 13 |
Hemorrhage | 49 | 20 |
Fatigue | 37 | 14 |
Bacterial infections | 32 | 28 |
Dyspnea | 32 | 7 |
Viral infections | 31 | 14 |
Thrombosis | 25 | 11 |
Diarrhea | 24 | 7 |
Rash | 23 | 3 |
Headache | 21 | 4 |
Hypertension | 20 | 13 |
Dizziness | 16 | 0 |
a Selected laboratory abnormalities are listed in Table 17 below b National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 4.03 |
Selected laboratory abnormalities during treatment with Jakafi are shown in Table 17.
Table 17: Acute Graft-Versus-Host Disease: Selected Laboratory Abnormalities Worsening from Baseline in the Open-Label, Single Cohort Study
Laboratory Parameter | Jakafi (N=71) |
|
Worst grade during treatment | ||
All Gradesa (%) | Grade 3-4 (%) | |
Hematology | ||
Anemia | 75 | 45 |
Thrombocytopenia | 75 | 61 |
Neutropenia | 58 | 40 |
Chemistry | ||
Elevated ALT | 48 | 8 |
Elevated AST | 48 | 6 |
Hypertriglyceridemia | 11 | 1 |
a National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03 |
Chronic Graft-Versus-Host Disease
In a Phase 3, randomized, open-label, multi-center study, 165 patients were treated with Jakafi and 158 patients were treated with best available therapy for cGVHD failing treatment with steroids with or without other immunosuppressive drugs [see Clinical Studies]; sixty-five patients crossed over from best available therapy to treatment with Jakafi, for a total of 230 patients treated with Jakafi. The median duration of exposure to Jakafi for the study was 49.7 weeks (range, 0.7 to 144.9 weeks) in the Jakafi arm. One hundred and nine (47%) patients were on Jakafi for at least 1 year.
There were five fatal adverse reactions to Jakafi, including 1 from toxic epidermal necrolysis and 4 from neutropenia, anemia and/or thrombocytopenia. An adverse reaction resulting in treatment discontinuation occurred in 18% of patients treated with Jakafi. An adverse reaction resulting in dose modification occurred in 27%, and an adverse reaction resulting in treatment interruption occurred in 23%. The most common hematologic adverse reactions (incidence > 35%) are anemia and thrombocytopenia. The most common nonhematologic adverse reactions (incidence ≥ 20%) are infections (pathogen not specified) and viral infection.
Table 18 presents the most frequent nonlaboratory adverse reactions occurring up to Cycle 7 Day 1 of randomized treatment.
Table 18: Chronic Graft-Versus-Host Disease: All-Grade (≥ 10%) and Grades 3-5 (≥ 3%) Nonlaboratory Adverse Reactions Occurring in Patients in the Open-Label, Active-controlled Study up to Cycle 7 Day 1 of Randomized Treatment
Adverse Reactionsb | Jakafi (N = 165) |
Best Available Therapy (N = 158) |
||
All Gradesa (%) | Grade ≥ 3 (%) | All Grades (%) | Grade ≥ 3 (%) | |
Infections and infestations | ||||
Infections (pathogen not specified) | 45 | 15 | 44 | 16 |
Viral infections | 28 | 5 | 23 | 5 |
Musculoskeletal and connective tissue disorders | ||||
Musculoskeletal pain | 18 | 1 | 13 | 0 |
General disorders and administration site conditions | ||||
Pyrexia | 16 | 2 | 9 | 1 |
Fatigue | 13 | 1 | 10 | 2 |
Edema | 10 | 1 | 12 | 1 |
Vascular disorders | ||||
Hypertension | 16 | 5 | 13 | 7 |
Hemorrhage | 12 | 2 | 15 | 2 |
Respiratory, thoracic and mediastinal disorders | ||||
Cough | 13 | 0 | 8 | 0 |
Dyspnea | 11 | 1 | 8 | 1 |
Gastrointestinal disorders | ||||
Nausea | 12 | 0 | 13 | 2 |
Diarrhea | 10 | 1 | 13 | 1 |
a National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 4.03 b Grouped terms that are composites of applicable adverse reaction terms. |
Clinically relevant laboratory abnormalities are shown in Table 19.
Table 19: Chronic Graft-Versus-Host Disease: Selected Laboratory Abnormalities in the Open-Label, Active-controlled Study up to Cycle 7 Day 1 of Randomized Treatmenta
Laboratory Test | Jakafi (N = 165) |
Best Available Therapy (N = 158) |
||
All Gradesb (%) | Grade ≥ 3 (%) | All Grades (%) | Grade ≥ 3 (%) | |
Hematology | ||||
Anemia | 82 | 13 | 75 | 8 |
Neutropenia | 27 | 12 | 23 | 9 |
Thrombocytopenia | 58 | 20 | 54 | 17 |
Chemistry | ||||
Hypercholesterolemia | 88 | 10 | 85 | 8 |
Elevated AST | 65 | 5 | 54 | 6 |
Elevated ALT | 73 | 11 | 71 | 16 |
Gamma glutamyltransferase increased | 81 | 42 | 75 | 38 |
Creatinine increased | 47 | 1 | 40 | 2 |
Elevated lipase | 38 | 12 | 30 | 9 |
Elevated amylase | 35 | 8 | 25 | 4 |
a Presented values are worst Grade values regardless of baseline b National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03 |
Postmarketing Experience
The following adverse reactions have been identified during post-approval use of Jakafi. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure:
- Infections and Infestations: Herpes simplex virus reactivation and/or dissemination
DRUG INTERACTIONS
Effect Of Other Drugs On Jakafi
Fluconazole
Concomitant use of Jakafi with fluconazole increases ruxolitinib exposure [see CLINICAL PHARMACOLOGY], which may increase the risk of exposure-related adverse reactions. Avoid concomitant use of Jakafi with fluconazole doses of greater than 200 mg daily. Reduce the Jakafi dosage when used concomitantly with fluconazole doses of less than or equal to 200 mg [see DOSAGE AND ADMINISTRATION].
Strong CYP3A4 Inhibitors
Concomitant use of Jakafi with strong CYP3A4 inhibitors increases ruxolitinib exposure [see CLINICAL PHARMACOLOGY], which may increase the risk of exposure-related adverse reactions. Reduce the Jakafi dosage when used concomitantly with strong CYP3A4 inhibitors except in patients with aGVHD or cGVHD [see DOSAGE AND ADMINISTRATION].
Strong CYP3A4 Inducers
Concomitant use of Jakafi with strong CYP3A4 inducers may decrease ruxolitinib exposure [see CLINICAL PHARMACOLOGY], which may reduce efficacy of Jakafi. Monitor patients frequently and adjust the Jakafi dose based on safety and efficacy [see CLINICAL PHARMACOLOGY].
Read the entire FDA prescribing information for Jakafi (Ruxolitinib)
© Jakafi Patient Information is supplied by Cerner Multum, Inc. and Jakafi Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.
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