xanthine oxidase Inhibitors
4 drugsAbout xanthine oxidase
Xanthine oxidase (XO) is an enzyme that catalyzes the oxidation of hypoxanthine to xanthine, and then xanthine to uric acid, playing a crucial role in purine metabolism. Elevated uric acid levels can lead to urate crystal formation, causing inflammation and pain.
Xanthine oxidase is a well-validated drug target, particularly for hyperuricemia and gout, with strong genetic support (max score 0.90). Loss-of-function variants in XDH are associated with increased risk of xanthinuria and protection against gout, suggesting inhibition is beneficial.
Four FDA-approved small molecule drugs target xanthine oxidase, including ZYLOPRIM, ALLOPURINOL SODIUM, ALOPRIM and ULORIC. These drugs are used to manage conditions resulting from excessive uric acid production.
xanthine oxidase Genetic Evidence Strong
Xanthine oxidase has strong genetic support with a max score of 0.90 linked to xanthinuria type II.
Strong genetic evidence increases confidence in targeting XO, potentially doubling clinical success rates.
💡 Why activation?
- • Loss-of-function variants increase disease risk (OR > 1) — restoring function may help
- • 67% directional consistency across 3 traits
- • Strong signal in nutritional or metabolic disease, genetic, familial or congenital disease pathways
Cross-Disease Effects
Trade-off: HighDirection of Effect
67% alignedEvidence Across Diseases
14 totalGWAS and other genetic studies link XDH to 14 diseases.
Loss-of-function causes disease; activation may help
Loss-of-function causes disease; activation may help
🔗 Colocalization Evidence 8 strong
max H4: 0.99eQTL/pQTL signals for XDH 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 xanthine oxidase Drugs
Four companies have approved drugs targeting xanthine oxidase, including Takeda, CASPER PHARMA LLC, Hikma and Viatris.
The presence of four companies indicates a moderately competitive landscape with potential entry barriers.
| Drug | Company | Approved | Indications |
|---|---|---|---|
| ALLOPURINOL SODIUM | Hikma | 2004 | 3 |
xanthine oxidase Drug Modality Landscape
Modalities
Routes of Administration
xanthine oxidase is amenable to small molecule drugs, with oral options available for convenient dosing.
The exclusive use of small molecules suggests an opportunity for novel modalities like antibodies.
xanthine oxidase Clinical Trials 166 trials
Phase 1-4 trials started in 2008 or later that test an FDA-approved drug acting on xanthine oxidase. Source: ClinicalTrials.gov. How we count
Completion by Phase
| Phase | Total | Completed | Stopped | Active | Completion |
|---|---|---|---|---|---|
| Phase 1 | 33 | 28 | 3 | 2 | 90% |
| Phase 2 | 66 | 49 | 7 | 10 | 88% |
| Phase 3 | 29 | 21 | 1 | 7 | 95% |
| Phase 4 | 38 | 29 | 4 | 5 | 88% |
Top Sponsors
By Modality
Top Conditions
Phase 3 Readout Calendar Pro
3 Phase 3 trials testing approved xanthine oxidase drugs across all sponsors.
Coverage: trials whose intervention is an approved drug targeting xanthine oxidase. Pre-approval candidates with development codes (e.g. AZD0901, MK-7240) are not yet linked. Anchored on CT.gov primary completion date.
xanthine oxidase Drug Approval Timeline (1966 - 2009)
The first drug was approved in 1966 (ZYLOPRIM) and the most recent in 2009 (ULORIC), spanning 44 years.
The approval timeline suggests a mature market with limited recent innovation, indicating potential saturation.
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Competitive Landscape
- • 4 companies competing
- • Market share by company
Full Drug Portfolio
- • All 4 approved drugs
- • Approval dates & indications
Genetic Validation
- • Full genetic evidence table
- • Effect sizes & directions
Approval Timeline
- • Full 4-drug timeline
- • First-of-modality markers
Clinical Trials Analysis
- • Sponsors: 89 (29 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 xanthine oxidase. A trial counts if an approved drug acting on xanthine oxidase 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.