IMPDH Inhibitors
5 drugsAbout IMPDH
Inosine monophosphate dehydrogenase (IMPDH) is an enzyme essential for guanine nucleotide synthesis, critical for DNA/RNA production, cell proliferation, and immune responses.
IMPDH is genetically linked to diseases like retinitis pigmentosa (score 0.89) and Leber congenital amaurosis (score 0.76), with loss-of-function variants increasing risk, suggesting activation may be beneficial.
Four FDA-approved small molecule drugs target IMPDH, including CellCept and Myfortic, developed by companies like Roche and Novartis, primarily for other therapeutic areas.
IMPDH Genetic Evidence Strong
IMPDH has strong genetic support with a max score of 0.89 linking it to multiple diseases.
Strong genetic evidence suggests that clinical trials targeting IMPDH have a higher chance of success.
💡 Why activation?
- • Loss-of-function variants increase disease risk (OR > 1) — restoring function may help
- • 100% directional consistency across 2 traits
- • Strong signal in nervous system disease, genetic, familial or congenital disease, disorder of visual system pathways
Cross-Disease Effects
Trade-off: LowDirection of Effect
100% alignedEvidence Across Diseases
9 totalGWAS and other genetic studies link IMPDH1 to 9 diseases.
Loss-of-function causes disease; activation may help
Loss-of-function causes disease; activation may help
🔗 Colocalization Evidence 9 strong
max H4: 1.00eQTL/pQTL signals for IMPDH1 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 IMPDH Drugs
The competitive landscape includes four companies with approved IMPDH-targeting drugs.
The presence of established players may present entry barriers, requiring a differentiated therapeutic approach.
| Drug | Company | Approved | Indications |
|---|---|---|---|
| CELLCEPT | Roche | 1995 | 1 |
| MYCOPHENOLATE MOFETIL | STRIDES PHARMA | 2008 | - |
IMPDH Drug Modality Landscape
Modalities
Routes of Administration
IMPDH is amenable to small molecule drugs, with oral options available for convenient dosing.
Explore alternative modalities like antibodies or biologics to differentiate from existing small molecule IMPDH inhibitors.
IMPDH Clinical Trials 388 trials
Phase 1-4 trials started in 2008 or later that test an FDA-approved drug acting on IMPDH. Source: ClinicalTrials.gov. How we count
Completion by Phase
| Phase | Total | Completed | Stopped | Active | Completion |
|---|---|---|---|---|---|
| Phase 1 | 68 | 33 | 12 | 22 | 73% |
| Phase 2 | 190 | 80 | 48 | 61 | 63% |
| Phase 3 | 57 | 39 | 9 | 9 | 81% |
| Phase 4 | 73 | 49 | 12 | 12 | 80% |
Top Sponsors
By Modality
Top Conditions
Top Drugs
Phase 3 Readout Calendar Pro
2 Phase 3 trials testing approved IMPDH drugs across all sponsors.
Coverage: trials whose intervention is an approved drug targeting IMPDH. Pre-approval candidates with development codes (e.g. AZD0901, MK-7240) are not yet linked. Anchored on CT.gov primary completion date.
IMPDH Drug Approval Timeline (1995 - 2024)
The first IMPDH-targeting drug was approved in 1995, with the most recent approval in 2024.
The recent approval suggests continued interest in IMPDH as a target, but also a potentially saturated market.
Pro Intelligence Preview
Deep insights for drug target analysis
Competitive Landscape
- • 5 companies competing
- • Market share by company
Full Drug Portfolio
- • All 5 approved drugs
- • Approval dates & indications
Genetic Validation
- • Full genetic evidence table
- • Effect sizes & directions
Approval Timeline
- • Full 5-drug timeline
- • First-of-modality markers
Clinical Trials Analysis
- • Sponsors: 173 (25 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 IMPDH. A trial counts if an approved drug acting on IMPDH 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.