Protein / target

Inosine-5'-monophosphate dehydrogenase 1

IMPDH1P20839Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
8
Approved medicines
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

IMP dehydrogenase activity

Strongest disease association

retinitis pigmentosa 10

Genetic evidence · score 0.89

Therapeutic maturity

Clinically validated target

8 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

8 approved · 1 in clinical development

30 linked trials

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function

Catalyzes the conversion of inosine 5'-phosphate (IMP) to xanthosine 5'-phosphate (XMP), the first committed and rate-limiting step in the de novo synthesis of guanine nucleotides, and therefore plays an important role in the regulation of cell growth. Could also have a single-stranded nucleic acid-binding activity and could play a role in RNA and/or DNA metabolism. It may also have a role in the development of malignancy and the growth progression of some tumors

Subcellular location

CytoplasmNucleus
Domains and Gene Ontology detail (19)

Domains & features

CBS 1CBS 2

Gene Ontology

  • Cazurophil granule lumen
  • Ccytoplasm
  • Ccytosol
  • Cextracellular region
  • Cficolin-1-rich granule lumen
  • Cnucleus
  • Csecretory granule lumen
  • FDNA binding
  • Fidentical protein binding
  • FIMP dehydrogenase activity
  • Fmetal ion binding
  • Fnucleic acid binding

514 aa · 55 kDa · 7 isoforms

Biological roles

Reactome v97

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Metabolic enzyme activityGO
View supporting evidence

Metabolic enzyme activity

  • ·IMP dehydrogenase activity
View underlying pathways (4)

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Interaction neighbourhood

STRING v12.0

Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.

GMPSIMPDH2ADSS2ATICADSS1AMPD2AMPD3AMPD1ITPAHPRT1IMPDH1

10 strongest partners — larger node and heavier line mean higher confidence

Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.

Drugs targeting this protein

2

Whether each drug engages this protein directly or through a complex, and how many other targets are recorded for it. Direct binders with few recorded targets are listed first.

Ribavirin
Narrow target profileApprovedInhibitor

Inosine-5'-monophosphate dehydrogenase 1 inhibitor

Appears in clinical studies involving chronic hepatitis C virus infection, fibrosis, chronic hepatitis C virus infection, cirrhosis of liver

Direct interaction with this protein · 1 of 2 recorded protein targets — narrow recorded profile

Mycophenolic Acid
ApprovedInhibitor

Inosine-5'-monophosphate dehydrogenase (IMPDH) inhibitor

Appears in clinical studies involving Crohn disease, immune system disorder, pulmonary sarcoidosis, graft versus host disease

Acts on a complex — shared with IMPDH2 · 1 of 2 recorded protein targets — narrow recorded profile

ChEMBL mechanism, action type and target identity. Open Targets clinical status and indications.

Translational evidence

Open Targets 26

Why this target matters therapeutically — disease associations, drugs in development, tractability and safety, from Open Targets.

Strongest genetic associations

Human genetic evidence — the most direct causal link between this target and a disease.

retinitis pigmentosa 100.89

Genetic · overall 0.68

retinitis pigmentosa0.80

Genetic · overall 0.73

Leber congenital amaurosis 110.76

Genetic · overall 0.60

Leber congenital amaurosis0.73

Genetic literature · overall 0.63

Highest-confidence therapeutic associations

Diseases where a drug acting on this target has already reached clinical development.

chronic hepatitis C virus infection0.99

Clinical · overall 0.60

hepatitis C virus infection0.99

Clinical · overall 0.60

cirrhosis of liver0.98

Clinical · overall 0.59

acute lymphoblastic leukemia0.87

Clinical · overall 0.53

viral infectious disease0.76

Clinical · overall 0.46

Highest overall evidence

Remaining associations by Open Targets' aggregated evidence score.

Crohn disease0.45

Clinical

Show all associations
retinitis pigmentosa0.73
retinitis pigmentosa 100.68
Leber congenital amaurosis0.63
chronic hepatitis C virus infection0.60
hepatitis C virus infection0.60
Leber congenital amaurosis 110.60
cirrhosis of liver0.59
acute lymphoblastic leukemia0.53
viral infectious disease0.46
Crohn disease0.45

Open Targets ranks 628 associations for this target and we store the top 10 by aggregated score. The long tail is largely literature co-mention and RNA-expression evidence, not evidence that this target drives those diseases.

Known drugs · 9 total

MYCOPHENOLATE MOFETIL HYDROCHLORIDEApproval
MYCOPHENOLIC ACIDApproval

Crohn disease · immune system disorder · pulmonary sarcoidosis

MYCOPHENOLATE MOFETILApproval

pemphigus vulgaris · kidney transplant · chronic graft versus host disease

MIZORIBINEApproval

lupus nephritis · nephrotic syndrome · rheumatoid arthritis

MYCOPHENOLATE SODIUMApproval

multiple sclerosis · kidney transplant · autoimmune disease

RIBAVIRINApproval

chronic hepatitis C virus infection · fibrosis · chronic hepatitis C virus infection

AVN-944Phase 2

exocrine pancreatic carcinoma · hematopoietic and lymphoid cell neoplasm

THIOGUANINEApproval

acute myeloid leukemia by FAB classification · acute lymphoblastic leukemia · neoplasm

MERIMEPODIBApproval

breast cancer · gastric adenocarcinoma · hepatitis C virus infection

Tractability

SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · Med-Quality PocketSM · Druggable FamilyAB · GO CC high confPR · Database UbiquitinationPR · Half-life DataPR · Small Molecule Binder

Safety liabilities

leukopeniagastrointestinal intoleranceacute rejection after kidney transplantation

Clinical trials

30

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein.

Show remaining trials (24)

ClinicalTrials.gov via the drug-target graph.

Forefront confidence

Synthesis

Our own weighting of the evidence behind each disease association. Human genetics and clinical evidence count for most; literature co-mention counts for little, because two entities sharing an abstract is not evidence that one drives the other.

retinitis pigmentosa 10Well supported
0.91
agreement 0.791.00
Genetic84%Animal model14%Literature2%Genetic literaturedup

Open Targets aggregate 0.68 · 3 independent evidence families · 1 not counted as duplicate

retinitis pigmentosaWell supported
0.88
agreement 0.760.99
Genetic68%Animal model30%Literature2%Genetic literaturedup

Open Targets aggregate 0.73 · 3 independent evidence families · 1 not counted as duplicate

Leber congenital amaurosis 11Well supported
0.79
agreement 0.670.91
Genetic84%Animal model15%Literature1%Genetic literaturedup

Open Targets aggregate 0.60 · 3 independent evidence families · 1 not counted as duplicate

chronic hepatitis C virus infectionModerately supported
0.74
agreement 0.580.91
Clinical100%

Open Targets aggregate 0.60 · 1 independent evidence family

hepatitis C virus infectionModerately supported
0.74
agreement 0.580.91
Clinical100%

Open Targets aggregate 0.60 · 1 independent evidence family

This ranking differs from Open Targets' own: re-weighting moves genetically-evidenced diseases above more heavily co-mentioned ones. The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the underlying per-type scores are shown above so the calculation can be checked.

What's happening now

60

Recent activity around this target, drawn from one canonical event stream. Every item is reached through 2 drugs that target this protein, so each event is news about that drug rather than about the protein directly.

  1. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA214376)

    fda · regulatory · fda · via Mycophenolic Acid

  2. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA202555)

    fda · regulatory · fda · via Mycophenolic Acid

  3. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA208315)

    fda · regulatory · fda · via Mycophenolic Acid

  4. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA091558)

    fda · regulatory · fda · via Mycophenolic Acid

  5. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (NDA050791)

    fda · regulatory · fda · via Mycophenolic Acid

  6. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA211173)

    fda · regulatory · fda · via Mycophenolic Acid

  7. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA217031)

    fda · regulatory · fda · via Mycophenolic Acid

  8. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA216637)

    fda · regulatory · fda · via Mycophenolic Acid

  9. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENILIC ACID (ANDA091248)

    fda · regulatory · fda · via Mycophenolic Acid

  10. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA214630)

    fda · regulatory · fda · via Mycophenolic Acid

  11. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA214289)

    fda · regulatory · fda · via Mycophenolic Acid

  12. Supplemental approval2026-07-29

    Supplemental approval: MYCOPHENOLIC ACID (ANDA218603)

    fda · regulatory · fda · via Mycophenolic Acid

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.