Pacritinib

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).

• VONJO 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 [see Clinical Studies ( 14 )] .

• VONJO 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 [see Warnings and Precautions ( 5.1 , 5.2 , 5.3 , 5.4 ), Drug Interactions ( 7.1 ), and Clinical Pharmacology ( 12.3 )] .contraindicated

Recommended dosage is 200 mg orally twice daily ( 2.1 ). May be taken with or without food ( 2.1 ). 2.1 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. 2.2 Monitoring for Safety Perform a complete blood count (CBC; including white blood cell count differential and platelet count), coagulation testing (prothrombin time, partial thromboplastin time, thrombin time, and international normalized ratio) and a baseline electrocardiogram (ECG), prior to starting VONJO, and monitor as clinically indicated while the patient is on treatment. 2.3 Missed Dose If a dose of VONJO is missed, the patient should take the next prescribed dose at its scheduled time. Extra capsules should not be taken to make up for the missed dose. 2.4 Dose Interruption for Planned Surgical Procedures or Other Interventions Discontinue VONJO 7 days prior to elective surgery or invasive procedures because of the risk of hemorrhage and restart only after hemostasis is assured. 2.5 Dose Modification for Adverse Reactions Dose modifications for diarrhea, thrombocytopenia, hemorrhage, and prolonged QT interval are described in Table 1 , Table 2 , Table 3 , and Table 4 respectively. See Warning and Precautions ( 5.1 , 5.2 , 5.3 , and 5.4 ) for additional risk minimization recommendations.

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 ( 5.1 ). Diarrhea: Manage significant diarrhea with anti-diarrheals, dose reduction, or dose interruption ( 5.2 ). Thrombocytopenia: Manage by dose reduction or interruption ( 5.3 ). 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 ( 5.4 ). Major Adverse Cardiac Events (MACE): Risk may be increased in current/past smokers and patients with other cardiovascular risk factors. Monitor for signs, evaluate and treat promptly ( 5.5 ). Thrombosis: Including deep venous thrombosis, pulmonary embolism, and arterial thrombosis may occur. Monitor for signs, evaluate and treat promptly ( 5.6 ). Secondary Malignancies: Lymphoma and other malignancies may occur. Past/current smokers may be at increased risk ( 5.7 ). Risk of Infection: Delay starting VONJO until active serious infections have resolved. Observe for signs and symptoms of infection and manage promptly ( 5.8 ). Symptom Exacerbation Following Interruption or Discontinuation: Manage with supportive care and consider resuming treatment with VONJO ( 5.9 ). 5.1 Hemorrhage Serious (11%) and fatal (2%) hemorrhages have occurred in VONJO-treated patients with platelet counts <100 x 10 9 /L.

The following clinically significant adverse reactions are described elsewhere in the labeling: Hemorrhage [see Warnings and Precautions ( 5.1 )] Diarrhea [see Warnings and Precautions ( 5.2 )] Thrombocytopenia [see Warnings and Precautions ( 5.3 )] Prolonged QT Interval [see Warnings and Precautions ( 5.4 )] Major Adverse Cardiac Events [see Warnings and Precautions ( 5.5 )] Thrombosis [see Warnings and Precautions ( 5.6 )] Secondary Malignancies [see Warnings and Precautions ( 5.7 )] Risk of Infection [see Warnings and Precautions ( 5.8 )] Symptom Exacerbation Following Interruption or Discontinuation of Treatment [see Warnings and Precautions ( 5.9 )] The most common (≥20% of patients) adverse reactions are diarrhea, thrombocytopenia, nausea, anemia, and peripheral edema ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Sobi, Inc. at (866) 773-5274 and www.VONJO.com or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 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. PERSIST-2 Trial The safety of VONJO was evaluated in the randomized, controlled PERSIST-2 trial [see Clinical Studies ( 14 )] . In PERSIST-2, key eligibility criteria included adults with intermediate or high-risk primary or secondary (post-polycythemia vera or post-essential thrombocythemia) MF with splenomegaly and a platelet count ≤100 × 10 9 /L.

Lactation: Advise not to breastfeed ( 8.2 ). Hepatic Impairment: For patients with severe hepatic impairment (Child-Pugh C), the recommended dosage is 100 mg twice daily ( 8.6 ). Renal Impairment: Avoid use in patients with eGFR <30 mL/min ( 8.7 ). 8.1 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. In animal reproduction studies, administration of pacritinib to pregnant mice or rabbits at exposures that were considerably lower than those observed at the recommended human dose were associated with maternal toxicity and embryonic and fetal loss (see Data ) . Advise pregnant women of the potential risk to a fetus. Consider the benefits and risks of VONJO for the mother and possible risks to the fetus when prescribing VONJO to a pregnant woman. The estimated background risk of major birth defects and miscarriage for the indicated population(s) is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Metabolism

Pacritinib steady-state mean (CV%) C max is 8.4 mg/L (32.4%) and AUC 0-12 is 95.6 mg×h/L (33.1%) following administration of VONJO 200 mg twice daily in patients with MF. Pharmacokinetics of pacritinib increases in a less than dose-proportional manner.

Overdosage may lead to gastrointestinal toxicities, myelosuppression, blurred vision, dizziness, worsening performance status, and sepsis. There is no known antidote for overdose with VONJO. Hemodialysis is not expected to enhance the elimination of VONJO.

• Feb 28, 2022NDANDA208712Sobi

1. 1Diarrhoea60021%
2. 2Off Label Use56420%
3. 3Fatigue36313%
4. 4Product Dose Omission Issue31311%
5. 5Death29010%
6. 6Platelet Count Decreased2799.8%
7. 7Nausea2769.7%
8. 8Haemoglobin Decreased2017.1%
9. 9Asthenia1435.0%
10. 10Drug Ineffective1123.9%
11. 11Dizziness1083.8%
12. 12Splenomegaly1023.6%
13. 13Constipation883.1%
14. 14Vomiting853.0%
15. 15Transfusion842.9%

The 10 most recently updated of 50 ClinicalTrials.gov registrations naming Pacritinib as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Pacritinib, a Kinase Inhibitor of CSF1R, IRAK1, JAK2, and FLT3, in Adults and Pediatric Participants 12 Years of Age or Older With Myelodysplastic Syndromes or Myelodysplastic/Myeloproliferative Neoplasms
  Recruiting · Phase 1 · Phase 2 · Interventional · 160 enrolled · National Cancer Institute (NCI)
  NCT06303193updated 2026-06-12
• Pacritinib With Aza for Upfront Myelodysplastic Syndrome
  Not yet recruiting · Phase 1 · Phase 2 · Interventional · 25 enrolled · Thomas Jefferson University
  NCT07387354updated 2026-06-10
• Phase II Study of Pacritinib in Kaposi Sarcoma Herpesvirus (KSHV)-Associated Multicentric Castleman Disease and KSHV-Associated Inflammatory Cytokine Syndrome (KICS)
  Recruiting · Phase 2 · Interventional · 75 enrolled · National Cancer Institute (NCI)
  NCT06052618updated 2026-06-01
• Study of Bemcentinib Plus Pacritinib In Patients With Advanced Lung Adenocarcinoma
  Terminated · Phase 1 · Phase 2 · Interventional · 4 enrolled · The University of Texas Health Science Center at San Antonio
  NCT06516887updated 2026-05-26
• Phase I/II Study of Pacritinib, A JAK2/IRAK1/CSF1R Inhibitor, in Refractory Chronic Graft-Versus-Host Disease (cGVHD) After Allogeneic Hematopoietic Stem Cell Transplantation (HSCT)
  Recruiting · Phase 1 · Phase 2 · Interventional · 50 enrolled · National Cancer Institute (NCI)
  NCT05531786updated 2026-05-22
• Combination of Tagraxofusp With Pacritinib in Patients With Intermediate-1 or Higher Myelofibrosis, Who Have Had Prior Therapy With the Approved JAK Inhibitors or in Which Therapy With the Approved JAK Inhibitors is Not Appropriate, Contraindicated or Declined
  Recruiting · Early phase 1 · Interventional · 20 enrolled · University of Kansas Medical Center
  NCT06414681updated 2026-05-06
• Pacritinib For Bone Marrow Fibrosis In Patients With Myelofibrosis Who Have Thrombocytopenia
  Recruiting · Phase 2 · Interventional · 30 enrolled · Grupo Español de Enfermedades Mieloproliferativas Crónicas PH Negativas
  NCT07394153updated 2026-05-04
• Pacritinib in Participants With Metastatic Castrate-Resistant Prostate Cancer That Progressed on or After Prior Treatment With Androgen Receptor Signaling Inhibitors
  Not yet recruiting · Phase 2 · Interventional · 32 enrolled · Medical College of Wisconsin
  NCT07226713updated 2026-05-04
• A Phase 3 Study of Pacritinib in Patients With Primary Myelofibrosis, Post Polycythemia Vera Myelofibrosis, or Post-Essential Thrombocythemia Myelofibrosis
  Active not recruiting · Phase 3 · Interventional · 407 enrolled · Swedish Orphan Biovitrum
  NCT03165734updated 2026-04-30
• A Study to Assess the Effectiveness and Safety of Pacritinib in Patients With VEXAS Syndrome (PAXIS)
  Recruiting · Phase 2 · Interventional · 78 enrolled · Swedish Orphan Biovitrum
  NCT06782373updated 2026-04-24

Frequently asked questions

How does Pacritinib work?

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).

What is Pacritinib used for?

According to FDA labeling, Pacritinib carries indications including: VONJO 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 [see Clinical Studies ( 14 )] .. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Pacritinib?

Pacritinib is classified as Janus-associated kinase (JAK) inhibitors, Kinase Inhibitor, Breast Cancer Resistance Protein Inhibitors, Cytochrome P450 1A2 Inhibitors, Cytochrome P450 3A4 Inhibitors, Janus Kinase Inhibitors, Kinase Inhibitors, Organic Cation Transporter 1 Inhibitors, P-Glycoprotein Inhibitors, Tyrosine Kinase Inhibitors.

What are the brand names for Pacritinib?

Pacritinib is marketed under brand names including Vonjo.

What are the contraindications for Pacritinib?

Pacritinib labeling lists contraindications including: VONJO 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 [see Warnings and Precautions ( 5.1 , 5.2 , 5.3 , 5.4 ), Drug Interactions ( 7.1 ), and Clinical Pharmacology ( 12.3 )] .. Always consult the full prescribing information and a clinician.