JAK1 Inhibitors
12 drugsAbout JAK1
Janus Kinase 1 (JAK1) is a non-receptor tyrosine kinase that mediates intracellular signaling pathways downstream of cytokine and growth factor receptors, influencing immune cell function and inflammatory responses.
JAK1 is a key immunology target supported by strong genetic evidence linking its variations to diseases like hypothyroidism (score 0.82) and autoinflammation (score 0.80). Strong eQTL/pQTL signals further support JAK1 as a therapeutic target.
JAK1 is targeted by 12 FDA-approved small molecule drugs including XELJANZ, RINVOQ and JAKAFI, indicated for immunology and other conditions. Multiple companies have approved JAK1 drugs, including PF PRISM CV, AbbVie, and INCYTE CORP.
JAK1 Genetic Evidence Strong
JAK1 has strong genetic support with a max score of 0.82 linking it to 12 diseases.
Strong genetic support suggests that clinical trials targeting genetically validated indications have a higher probability of success.
Evidence Across Diseases
12 totalGWAS and other genetic studies link JAK1 to 12 diseases.
🔗 Colocalization Evidence 20 strong
max H4: 1.00eQTL/pQTL signals for JAK1 colocalize with these GWAS traits, providing causal evidence that gene expression changes drive disease risk.
Understanding these scores
Association Score (0-1): Combines all evidence types (genetic, literature, drugs, animal models). Higher = more evidence linking target to disease. This is a ranking heuristic, not a confidence score.
L2G Score: Open Targets uses a machine learning model (Locus-to-Gene) to predict which gene is causal at each GWAS locus. L2G=0.5 means ~50% probability of being the causal gene. Only associations with L2G > 0.05 are included.
Odds Ratio (OR): From gene burden studies (UK Biobank, AstraZeneca PheWAS). Measures how loss-of-function variants affect disease risk. OR<1 = protective (inhibiting target may help), OR>1 = risk (losing function causes disease).
Beta (β): Effect size for continuous traits. β<0 = protective, β>0 = risk.
Clinical Translation (~1.8x): Based on Nelson et al. 2015: drug targets with genetic evidence have ~2x higher success rates in clinical trials. We estimate: Strong support (score ≥0.7) → ~1.8x, Moderate (0.3-0.7) → ~1.3x, Weak → baseline.
Colocalization (H4): Tests whether a GWAS signal and an eQTL/pQTL signal share the same causal variant. H4 is the posterior probability that both traits are associated AND share a causal variant. H4 > 0.8 = strong evidence that gene expression/protein levels drive disease risk. This links genetic variation → gene expression → disease, supporting the target-disease connection.
Top JAK1 Drugs
Nine companies have approved JAK1 drugs, with PF PRISM CV, AbbVie, and INCYTE CORP leading the market.
The presence of multiple players indicates a competitive market, requiring differentiated strategies for new entrants.
| Drug | Company | Approved | Indications |
|---|---|---|---|
| XELJANZ XR | Pfizer | 2016 | 5 |
| RINVOQ LQ | AbbVie | 2024 | 4 |
| OLUMIANT | Eli Lilly | 2018 | 3 |
| OPZELURA | INCYTE CORP | 2021 | 2 |
| GAVRETO | RIGEL PHARMS | 2020 | 2 |
| OJJAARA | GSK | 2023 | 2 |
| ANZUPGO | LEO PHARMA AS | 2025 | 1 |
| LEQSELVI | Sun Pharma | 2024 | 1 |
| CIBINQO | Pfizer | 2022 | 1 |
JAK1 Drug Modality Landscape
Modalities
Routes of Administration
JAK1 is amenable to small molecule drugs, with oral options available for convenient dosing.
The absence of other modalities represents a whitespace opportunity for novel therapeutic approaches like antibodies or biologics.
JAK1 Clinical Trials 691 trials
Phase 1-4 trials started in 2008 or later that test an FDA-approved drug acting on JAK1. Source: ClinicalTrials.gov. How we count
Completion by Phase
| Phase | Total | Completed | Stopped | Active | Completion |
|---|---|---|---|---|---|
| Phase 1 | 186 | 91 | 23 | 72 | 80% |
| Phase 2 | 278 | 119 | 42 | 117 | 74% |
| Phase 3 | 172 | 86 | 22 | 64 | 80% |
| Phase 4 | 55 | 16 | 4 | 35 | 80% |
Top Sponsors
By Modality
Top Conditions
Phase 3 Readout Calendar Pro
8 Phase 3 trials testing approved JAK1 drugs across all sponsors.
Coverage: trials whose intervention is an approved drug targeting JAK1. Pre-approval candidates with development codes (e.g. AZD0901, MK-7240) are not yet linked. Anchored on CT.gov primary completion date.
JAK1 Drug Approval Timeline (2011 - 2025)
The first JAK1 drug was approved in 2011, with the most recent approval in 2025, spanning 15 years.
Continued approvals suggest sustained interest in JAK1, but increasing competition may indicate market saturation.
Pro Intelligence Preview
Deep insights for drug target analysis
Competitive Landscape
- • 8 companies competing
- • Market share by company
Full Drug Portfolio
- • All 12 approved drugs
- • Approval dates & indications
Genetic Validation
- • Full genetic evidence table
- • Effect sizes & directions
Approval Timeline
- • Full 12-drug timeline
- • First-of-modality markers
Clinical Trials Analysis
- • Sponsors: 245 (50 companies)
- • Completion rates by condition
Full summary • All drugs • Genetic evidence • Trials • Timeline
How We Count Trials
- Trials: phase 1-4 interventional trials on ClinicalTrials.gov that started in 2008 or later and test an FDA-approved drug acting on JAK1. A trial counts if an approved drug acting on JAK1 is in any arm, including as a comparator, and a trial that tests two such drugs counts once. Trials that test only unapproved drugs are not counted. A trial listed as phase 1/2 counts as phase 1, and phase 2/3 as phase 2.
- Active: recruiting, not yet recruiting, enrolling by invitation, or active and no longer recruiting.
- Completion rate: of the trials that have ended, the share marked Completed rather than Terminated or Withdrawn. Completed means the trial ended as planned; it does not mean the drug worked. Suspended trials are not counted as ended.
- Stopped: terminated or withdrawn. Trials stop for many reasons, including slow enrolment and business decisions, not only safety or efficacy.
- Sponsors: the lead sponsor of each trial. Companies are the sponsors ClinicalTrials.gov classes as industry; the rest are universities, hospitals, cooperative groups, government bodies and individuals.