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JAK Inhibitor
JAK inhibitors block Janus kinase enzymes, which are intracellular signaling proteins that transmit inflammatory and immune signals from cell surface receptors.
JAK inhibitors block Janus kinase enzymes, which are intracellular signaling proteins that transmit inflammatory and immune signals from cell surface receptors. Used for Myeloproliferative neoplasms (e.g., polycythemia vera, essential thrombocythemia, primary myelofibrosis), Hematologic malignancies and related conditions.
At a glance
| Generic name | JAK Inhibitor |
|---|---|
| Also known as | JAK inhibitors, Janus Kinase Inhibitor, Ruxolitinib, Fedratinib, Tofacitinib, baricitinib, or upadacitinib |
| Sponsor | Fred Hutchinson Cancer Center |
| Drug class | JAK inhibitor |
| Target | JAK1, JAK2, JAK3, and/or TYK2 |
| Modality | Small molecule |
| Therapeutic area | Oncology, Immunology |
| Phase | FDA-approved |
Mechanism of action
JAK inhibitors work by inhibiting one or more of the four JAK family kinases (JAK1, JAK2, JAK3, TYK2), thereby suppressing the JAK-STAT signaling pathway. This pathway is critical for cytokine and growth factor signaling in immune and hematopoietic cells. By blocking JAK activity, these inhibitors reduce inflammatory cytokine production and immune cell activation, making them useful in both hematologic malignancies and inflammatory/autoimmune conditions.
Approved indications
- Myeloproliferative neoplasms (e.g., polycythemia vera, essential thrombocythemia, primary myelofibrosis)
- Hematologic malignancies and related conditions
Common side effects
- Thrombocytopenia
- Anemia
- Infections
- Elevated cholesterol
- Gastrointestinal disturbances
Key clinical trials
- Randomized Double-Blind Placebo-Controlled Trial EValuating Baricitinib on PERSistent NEurologic and Cardiopulmonary Symptoms of Long COVID (PHASE3)
- A Vaccine (VSV-hIFNβ-NIS) With or Without Cyclophosphamide and Combinations of Ipilimumab, Nivolumab, and Cemiplimab in Treating Relapsed or Refractory Multiple Myeloma, Acute Myeloid Leukemia or Lymphoma (PHASE1)
- Safety of Tofacitinib, an Oral Janus Kinase Inhibitor, in Primary Sjogren Disease (PHASE2)
- Safety and Efficacy of Tofacitinib for Chronic Granulomatous Disease With Inflammatory Complications (PHASE1, PHASE2)
- Ruxolitinib in Combination With Venetoclax With and Without Azacitidine in Treating Patients With Relapsed or Refractory Acute Myeloid Leukemia (PHASE1)
- A Prospective Cohort Study Evaluating the Efficacy and Safety of Guselkumab (GUS) With JAK Inhibitors in Patients With Difficult-To-Treat Inflammatory Bowel Disease (IBD)
- Baricitinib for Reduction of HIV - CNS (PHASE2)
- Efficacy and Safety of Baricitinib in Oral Lichen Planus: a Proof-of-Concept Study (PHASE2)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- JAK Inhibitor CI brief — competitive landscape report
- JAK Inhibitor updates RSS · CI watch RSS
- Fred Hutchinson Cancer Center portfolio CI