Momelotinib

Momelotinib is an inhibitor of wild type Janus Kinase 1 and 2 (JAK1/JAK2) and mutant JAK2 V617F , which contribute to signaling of a number of cytokines and growth factors that are important for hematopoiesis and immune function. Momelotinib and its major human circulating metabolite, M21, have higher inhibitory activity for JAK2 compared to JAK3 and tyrosine kinase 2 (TYK2).

• OJJAARA is indicated for the treatment of intermediate or high‑risk myelofibrosis (MF), including primary MF or secondary MF [post‑polycythemia vera (PV) and post‑essential thrombocythemia (ET)], in adults with anemia. OJJAARA is a kinase inhibitor indicated for the treatment of intermediate or high‑risk myelofibrosis (MF), including primary MF or secondary MF [post‑polycythemia vera (PV) and post‑essential thrombocythemia (ET)], in adults with anemia.ICD-10: D64.9

• None. None.contraindicated

• Recommended dosage: 200 mg orally once daily with or without food. ( 2.1 ) • Severe hepatic impairment (Child-Pugh Class C): Reduce the starting dose to 150 mg orally once daily. ( 2.3 ) 2.1 Recommended Dosage The recommended dosage of OJJAARA is 200 mg orally once daily. OJJAARA may be taken with or without food. Swallow OJJAARA tablets whole. Do not cut, crush, or chew tablets. If a dose of OJJAARA is missed, the next scheduled dose should be taken the following day. 2.2 Laboratory Monitoring for Safety Obtain the following blood tests prior to starting treatment with OJJAARA, periodically during treatment, and as clinically indicated: • Complete blood count (CBC) with platelets [see Warnings and Precautions ( 5.2 )] • Hepatic panel [see Warnings and Precautions ( 5.3 )] 2.3 Dosage Modification for Hepatic Impairment The recommended starting dosage in patients with severe hepatic impairment (Child‑Pugh Class C) is 150 mg orally once daily [see Use in Specific Populations ( 8.6 )] . No dose adjustment is recommended for patients with mild or moderate hepatic impairment. 2.4 Dosage Modification for Adverse Reactions Manage hematologic and non‑hematologic adverse reactions as described in Table 1 . Table 1: Dose Modifications for OJJAARA-Related Adverse Reactions ALT = alanine transaminase; AST = aspartate transaminase; ULN = upper limit of normal. a Reinitiate or escalate treatment up to starting dosage as clinically appropriate. b May reinitiate treatment at 100 mg if previously dosed at 100 mg. c If baseline >2 × ULN. d If baseline >1.5 × ULN.

• Risk of Infections: Do not initiate OJJAARA in patients with an active infection. Monitor for signs and symptoms of infection, including reactivation of hepatitis B, and initiate appropriate treatment promptly. ( 5.1 ) • Thrombocytopenia and Neutropenia: Manage by dose reduction or interruption. ( 5.2 ) • Hepatotoxicity: Obtain liver tests before initiation of and periodically throughout treatment with OJJAARA. ( 5.3 ) • Severe Cutaneous Adverse Reactions (SCARs): Monitor for signs and symptoms, and interrupt OJJAARA until etiology of reaction has been determined. ( 5.4 ) • Major Adverse Cardiovascular Events (MACE): Monitor for symptoms, evaluate and treat promptly. ( 5.5 ) • Thrombosis: Evaluate and treat symptoms of thrombosis promptly. ( 5.6 ) • Malignancies: Monitor for development of secondary malignancies, particularly in current or past smokers. ( 5.7 ) • Symptom Exacerbation Following Interruption or Discontinuation of Treatment: Manage with supportive care and consider restarting OJJAARA. ( 5.8 ) 5.1 Risk of Infections Serious (including fatal) infections (e.g., bacterial and viral, including COVID‑19) occurred in 13% of patients treated with OJJAARA. Infections regardless of grade occurred in 38% of patients treated with OJJAARA [see Adverse Reactions ( 6.1 )] . Delay starting therapy with OJJAARA until active infections have resolved. Monitor patients receiving OJJAARA for signs and symptoms of infection and initiate appropriate treatment promptly.

The following clinically significant adverse reactions are described elsewhere in the labeling: • Risk of Infections and Hepatitis B Reactivation [see Warnings and Precautions ( 5.1 )] • Thrombocytopenia and Neutropenia [see Warnings and Precautions ( 5.2 )] • Hepatotoxicity [see Warnings and Precautions ( 5.3 )] • Severe Cutaneous Adverse Reactions [see Warnings and Precautions ( 5.4 )] • Major Adverse Cardiovascular Events [see Warnings and Precautions ( 5.5 )] • Thrombosis [see Warnings and Precautions ( 5.6 )] • Malignancies [see Warnings and Precautions ( 5.7 )] • Symptom Exacerbation Following Interruption or Discontinuation of Treatment [see Warnings and Precautions ( 5.8 )] The most common adverse reactions (≥20% in either study) are thrombocytopenia, hemorrhage, bacterial infection, fatigue, dizziness, diarrhea, and nausea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact GlaxoSmithKline at 1-888-825-5249 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 with rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of OJJAARA was evaluated in 215 patients in 2 clinical trials (MOMENTUM and SIMPLIFY‑1 anemic subgroup [hemoglobin (Hb) <10 g/dL]) [see Clinical Studies ( 14 )] .

• Pregnancy: May cause fetal harm. ( 8.1 ) • Lactation: Advise not to breastfeed. ( 8.2 ) 8.1 Pregnancy Risk Summary Available data on the use of OJJAARA in pregnant women are insufficient to determine whether there is a drug‑associated risk for major birth defects or miscarriage. Based on animal reproduction studies conducted in rats and rabbits, momelotinib may cause embryo‑fetal toxicity at exposures lower than the expected exposure in patients receiving 200 mg once daily (see Data) . OJJAARA should only be used during pregnancy if the expected benefits to the mother outweigh the potential risks to the fetus. The background risk of major birth defects and miscarriage for the indicated population 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. Data Animal Data: In an embryofetal development study, pregnant rats received momelotinib 2, 6 or 12 mg/kg/day orally, during the period of organogenesis (Gestation Day 6 to 17). Embryo‑fetal toxicity (embryonic death, soft tissue anomalies, skeletal variations, and lower mean fetal body weights) was observed at 12 mg/kg (in the presence of maternal toxicity).

Metabolism

Momelotinib pharmacokinetic parameters are presented as mean (%CV) and were derived in patients with MF unless otherwise specified. The momelotinib steady‑state C max is 479 ng/mL (61%) and AUC is 3,288 ng•h/mL (60%) at the maximum recommended dosage.

There is no known antidote for overdose with OJJAARA. If overdose is suspected, the patient should be monitored for signs or symptoms of adverse reactions or effects, and appropriate supportive treatment should be instituted immediately. Further management should be as clinically indicated. Hemodialysis is not expected to enhance the elimination of momelotinib. Consider contacting the Poison Help line (1‑800‑222‑1222) or a medical toxicologist for additional overdose management recommendations.

• Sep 15, 2023NDANDA216873Glaxosmithkline

1. 1Thrombocytopenia1028.7%
2. 2Death877.4%
3. 3Drug Ineffective857.2%
4. 4Anaemia796.7%
5. 5Myelofibrosis756.4%
6. 6Diarrhoea665.6%
7. 7Fatigue595.0%
8. 8Condition Aggravated554.7%
9. 9Pneumonia554.7%
10. 10Haemoglobin Decreased514.3%
11. 11Platelet Count Decreased514.3%
12. 12Dizziness504.3%
13. 13Neuropathy Peripheral474.0%
14. 14Nausea463.9%
15. 15Splenomegaly413.5%

The 10 most recently updated of 29 ClinicalTrials.gov registrations naming Momelotinib as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• A Phase I/II Study of Gilteritinib and Momelotinib for Patients With Relapsed or Refractory FLT3-Mutated Acute Myeloid Leukemia
  Active not recruiting · Phase 1 · Phase 2 · Interventional · 20 enrolled · M.D. Anderson Cancer Center
  NCT06235801updated 2026-06-10
• A Study of JNJ-88549968 for the Treatment of Calreticulin (CALR)-Mutated Myeloproliferative Neoplasms
  Recruiting · Phase 1 · Interventional · 220 enrolled · Janssen Research & Development, LLC
  NCT06150157updated 2026-06-05
• A Study of Momelotinib in Participants With Low-risk Myelodysplastic Syndrome
  Recruiting · Phase 2 · Interventional · 80 enrolled · GlaxoSmithKline
  NCT06847867updated 2026-06-02
• A Study Evaluating the Efficacy and Safety of Momelotinib in Participants With Vacuoles, E1-enzyme, X-linked, Autoinflammatory, Somatic (VEXAS) Syndrome
  Not yet recruiting · Phase 2 · Phase 3 · Interventional · 136 enrolled · GlaxoSmithKline
  NCT07569081updated 2026-06-01
• A Study of Oral Nuvisertib (TP-3654) in Patients With Myelofibrosis
  Recruiting · Phase 1 · Phase 2 · Interventional · 240 enrolled · Sumitomo Pharma America, Inc.
  NCT04176198updated 2026-05-01
• Extended Access of Momelotinib in Adults With Myelofibrosis
  Active not recruiting · Phase 2 · Interventional · 237 enrolled · GlaxoSmithKline
  NCT03441113updated 2026-04-20
• Study of Momelotinib in Combination With Luspatercept in Participants With Transfusion Dependent Myelofibrosis
  Recruiting · Phase 2 · Interventional · 68 enrolled · GlaxoSmithKline
  NCT06517875updated 2026-04-20
• Comparing Momelotinib and Ruxolitinib in People With Untreated Myelofibrosis and Low Blood Cell Counts
  Not yet recruiting · Phase 4 · Interventional · 268 enrolled · SWOG Cancer Research Network
  NCT07498205updated 2026-04-09
• Momelotinib During and After HCT in Myelofibrosis
  Recruiting · Phase 1 · Interventional · 28 enrolled · Massachusetts General Hospital
  NCT07104799updated 2026-03-31
• Momelotinib in Combination With Hypomethylating Agent for Chronic Phase Myelodysplastic Syndromes/Myeloproliferative Overlap Neoplasms and Chronic Neutrophilic Leukemia
  Recruiting · Early phase 1 · Interventional · 18 enrolled · Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins
  NCT07071155updated 2026-03-27

Frequently asked questions

How does Momelotinib work?

Momelotinib is an inhibitor of wild type Janus Kinase 1 and 2 (JAK1/JAK2) and mutant JAK2 V617F , which contribute to signaling of a number of cytokines and growth factors that are important for hematopoiesis and immune function. Momelotinib and its major human circulating metabolite, M21, have higher inhibitory activity for JAK2 compared to JAK3 and tyrosine kinase 2 (TYK2).

What is Momelotinib used for?

According to FDA labeling, Momelotinib carries indications including: OJJAARA is indicated for the treatment of intermediate or high‑risk myelofibrosis (MF), including primary MF or secondary MF [post‑polycythemia vera (PV) and post‑essential thrombocythemia (ET)], in adults with anemia. OJJAARA is a kinase inhibitor indicated for the treatment of intermediate or high‑risk myelofibrosis (MF), including primary MF or secondary MF [post‑polycythemia vera (PV) and post‑essential thrombocythemia (ET)], in adults with anemia.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Momelotinib?

Momelotinib is classified as Janus-associated kinase (JAK) inhibitors, Janus Kinase Inhibitors, Decreased Cytokine Activity, Transcription to RNA Alteration.

What are the brand names for Momelotinib?

Momelotinib is marketed under brand names including Ojjaara.

What are the contraindications for Momelotinib?

Momelotinib labeling lists contraindications including: None. None.. Always consult the full prescribing information and a clinician.