opentargets-database

name	opentargets-database
description	Query Open Targets GraphQL API for target-disease associations, evidence, drug links, safety. Search targets by gene, diseases by EFO ID; scores from 20+ sources, drug mechanisms, tractability. For ChEMBL use chembl-database-bioactivity; for trials use clinicaltrials-database-search.
license	Apache-2.0

Open Targets Platform Database

Overview

Open Targets Platform integrates evidence from genetics, genomics, literature, and drug databases to systematically score target-disease associations for 60,000+ targets and 20,000+ diseases/phenotypes. The public GraphQL API (no authentication required) provides access to association scores, evidence from 20+ data sources (GWAS, ClinVar, ChEMBL, drugs, pathways, mouse models, expression), and detailed drug-target-disease triangles.

When to Use

• Ranking therapeutic targets for a disease by overall association score and evidence breakdown
• Finding all diseases associated with a gene of interest and their confidence scores
• Retrieving approved and investigational drugs for a target, with mechanism of action and clinical phase
• Assessing target druggability and tractability (small molecule, antibody, PROTAC likelihood)
• Pulling genetic association evidence (GWAS hits, variant-to-gene mappings) for a target-disease pair
• Exploring safety/adverse event data for a drug target from FAERS and literature
• For bioactivity IC50/Ki data use chembl-database-bioactivity; for clinical trial details use clinicaltrials-database-search

Prerequisites

• Python packages: requests
• Data requirements: gene symbols (HGNC), Ensembl gene IDs, disease EFO IDs, or drug names
• Environment: internet connection; no authentication needed
• Rate limits: no hard limit stated; use reasonable delays for large queries (>100 targets)

pip install requests

Quick Start

import requests

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

# Top disease associations for BRCA1
query = """
query TargetDiseases($ensgId: String!) {
  target(ensemblId: $ensgId) {
    id
    approvedSymbol
    associatedDiseases(page: {index: 0, size: 5}) {
      rows {
        disease { id name }
        score
      }
    }
  }
}
"""
data = ot_query(query, {"ensgId": "ENSG00000012048"})
target = data["target"]
print(f"Target: {target['approvedSymbol']}")
for row in target["associatedDiseases"]["rows"]:
    print(f"  {row['disease']['name']}: {row['score']:.3f}")

Core API

Query 1: Target Lookup by Gene Symbol

Search for a target and retrieve basic metadata (Ensembl ID, biotype, description).

import requests

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

# Search by gene symbol
query = """
query SearchTarget($sym: String!) {
  search(queryString: $sym, entityNames: ["target"]) {
    hits {
      id
      name
      entity
      object {
        ... on Target {
          approvedSymbol
          approvedName
          biotype
          functionDescriptions
        }
      }
    }
  }
}
"""
data = ot_query(query, {"sym": "BRCA1"})
for hit in data["search"]["hits"][:3]:
    obj = hit.get("object", {})
    print(f"ID: {hit['id']} | {obj.get('approvedSymbol')} | {obj.get('biotype')}")
    descs = obj.get("functionDescriptions", [])
    if descs:
        print(f"  Function: {descs[0][:120]}")

# Direct lookup by Ensembl ID
query2 = """
query Target($ensgId: String!) {
  target(ensemblId: $ensgId) {
    id approvedSymbol approvedName biotype
    tractability { label modality value }
  }
}
"""
data2 = ot_query(query2, {"ensgId": "ENSG00000141510"})  # TP53
t = data2["target"]
print(f"\n{t['approvedSymbol']} ({t['id']}): {t['biotype']}")
print("Tractability:")
for tr in t.get("tractability", [])[:5]:
    print(f"  {tr['modality']} | {tr['label']}: {tr['value']}")

Query 2: Target-Disease Associations

Retrieve association scores for a target across all associated diseases.

import requests, pandas as pd

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

query = """
query Associations($ensgId: String!, $size: Int!) {
  target(ensemblId: $ensgId) {
    approvedSymbol
    associatedDiseases(page: {index: 0, size: $size}, orderByScore: "score") {
      count
      rows {
        disease { id name therapeuticAreas { name } }
        score
        datatypeScores { id score }
      }
    }
  }
}
"""
data = ot_query(query, {"ensgId": "ENSG00000012048", "size": 20})
target = data["target"]
assoc = target["associatedDiseases"]
print(f"{target['approvedSymbol']}: {assoc['count']} associated diseases")

rows = []
for r in assoc["rows"]:
    scores = {d["id"]: d["score"] for d in r.get("datatypeScores", [])}
    rows.append({
        "disease": r["disease"]["name"],
        "disease_id": r["disease"]["id"],
        "overall_score": round(r["score"], 4),
        "genetics": (scores.get(, ), ),
        : (scores.get(, ), ),
        : (scores.get(, ), ),
    })

df = pd.DataFrame(rows)
(df.head().to_string(index=))

Query 3: Disease-Target Associations

Given a disease, retrieve all associated targets ranked by score.

import requests, pandas as pd

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

query = """
query DiseaseTargets($efoId: String!, $size: Int!) {
  disease(efoId: $efoId) {
    id name
    associatedTargets(page: {index: 0, size: $size}, orderByScore: "score") {
      count
      rows {
        target { id approvedSymbol biotype }
        score
        datatypeScores { id score }
      }
    }
  }
}
"""
# EFO_0000305 = breast carcinoma
data = ot_query(query, {"efoId": "EFO_0000305", "size": 10})
disease = data["disease"]
print(f"Disease: {disease['name']}")
print(f"Total associated targets: {disease['associatedTargets']['count']}")

for row in disease["associatedTargets"]["rows"][:5]:
    t = row["target"]
    print(f"  {t['approvedSymbol']:12s} score={row['score']:.3f} biotype={t['biotype']}")

Query 4: Known Drugs for a Target

Retrieve approved and investigational drugs, their mechanism, and clinical phase.

import requests, pandas as pd

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

query = """
query KnownDrugs($ensgId: String!) {
  target(ensemblId: $ensgId) {
    approvedSymbol
    drugAndClinicalCandidates {
      count
      rows {
        maxClinicalStage
        drug { id name drugType maximumClinicalStage mechanismsOfAction { rows { mechanismOfAction } } }
        diseases { disease { id name } }
      }
    }
  }
}
"""
data = ot_query(query, {"ensgId": "ENSG00000146648"})  # EGFR
target = data["target"]
drugs_data = target["drugAndClinicalCandidates"]
print(f"{target['approvedSymbol']}: {drugs_data['count']} drug-indication pairs")

rows = []
for r in drugs_data["rows"]:
    drug = r["drug"]
    moa = drug.get("mechanismsOfAction") or {}
    moa_first = (moa.get("rows") or [{}])[0].get("mechanismOfAction")
    first_disease = (r.get("diseases") or [{}])[0].get("disease") or {}
    rows.append({
        "drug": drug["name"],
        "type": drug["drugType"],
        : r[],
        : drug[] == ,
        : first_disease.get(, ),
        : moa_first,
    })

df = pd.DataFrame(rows).drop_duplicates(subset=[, ])
(df.head().to_string(index=))

Query 5: Evidence for a Specific Target-Disease Pair

Retrieve detailed evidence records (GWAS, ClinVar, literature) for a target-disease pair.

import requests

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

query = """
query Evidence($ensgId: String!, $efoId: String!) {
  disease(efoId: $efoId) {
    evidences(
      ensemblIds: [$ensgId]
      enableIndirect: true
      size: 10
      datasourceIds: ["gwas_catalog", "clinvar", "chembl"]
    ) {
      count
      rows {
        datasourceId
        score
        variantRsId
        studyId
        publicationYear
        clinicalSignificances
      }
    }
  }
}
"""
data = ot_query(query, {"ensgId": "ENSG00000012048", "efoId": "EFO_0000305"})
evidences = data["disease"]["evidences"]
print(f"Evidence records: {evidences['count']}")
for ev in evidences["rows"][:5]:
    print(f"  Source: {ev['datasourceId']:20s} | Score: {ev['score']:.3f}")

Query 6: Safety and Adverse Events

Retrieve known adverse events and safety data for a target.

import requests

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

query = """
query Safety($ensgId: String!) {
  target(ensemblId: $ensgId) {
    approvedSymbol
    safetyLiabilities {
      event
      effects { direction dosing }
      biosamples { tissueLabel cellLabel }
      datasource
    }
  }
}
"""
data = ot_query(query, {"ensgId": "ENSG00000146648"})  # EGFR
target = data["target"]
print(f"Safety liabilities for {target['approvedSymbol']}:")
for s in target.get("safetyLiabilities", [])[:5]:
    print(f"  Event: {s['event']}")
    # 2025 schema: `datasource` is a scalar literature-citation string,
    # not the legacy `datasources[{name, pmid}]` list of objects
    print(f"    Source: {s.get('datasource', 'n/a')}")
    for eff in s.get("effects", []) or []:
        print(f"    Effect: direction={eff.get('direction')} dosing={eff.get('dosing')}")

Key Concepts

Association Scores

Open Targets uses harmonic sum aggregation to combine evidence from multiple data sources into a 0–1 association score. Subscores include: genetic_association, somatic_mutation, known_drug, affected_pathway, literature, RNA_expression, animal_model, and others. Higher scores indicate more and stronger evidence.

EFO IDs for Diseases

Open Targets uses Experimental Factor Ontology (EFO) identifiers for diseases (e.g., EFO_0000305 for breast carcinoma). Search by disease name using the search query to find EFO IDs before querying associations.

Common Workflows

Workflow 1: Target Prioritization for a Disease

Goal: Given a disease, rank all associated targets by overall score and export with evidence breakdown.

import requests, pandas as pd, time

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

def disease_search(name):
    q = 'query S($q:String!){search(queryString:$q,entityNames:["disease"]){hits{id name}}}'
    data = ot_query(q, {"q": name})
    return [(h["id"], h["name"]) for h in data["search"]["hits"][:3]]

def get_top_targets(efo_id, n=50):
    q = """
    query($efoId:String!,$size:Int!){
      disease(efoId:$efoId){
        name
        associatedTargets(page:{index:0,size:$size},orderByScore:"score"){
          count
          rows{
            target{id approvedSymbol biotype}
            score
            datatypeScores { id score }
          }
        }
      }
    }"""
    data = ot_query(q, {"efoId": efo_id, "size": n})
    disease = data["disease"]
    rows = []
    for row in disease["associatedTargets"]["rows"]:
        t = row["target"]
        scores = {d["id"]: round(d["score"], 3) for d  row.get(, [])}
        rows.append({
            : t[],
            : t[],
            : t[],
            : (row[], ),
            **scores
        })
     disease[], pd.DataFrame(rows)


candidates = disease_search()
(, candidates)


disease_name, df = get_top_targets(, n=)
df.to_csv(, index=)
()
cols = [c  c  [, , , , , , ]  c  df.columns]
(df[cols].head().to_string(index=))

Workflow 2: Drug-Target-Disease Triangle

Goal: For a target, retrieve all drugs and their associated indications and phases.

import requests, pandas as pd

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

def ot_query(gql, variables=None):
    r = requests.post(OT_URL, json={"query": gql, "variables": variables or {}})
    r.raise_for_status()
    return r.json()["data"]

query = """
query($ensgId:String!){
  target(ensemblId:$ensgId){
    approvedSymbol
    drugAndClinicalCandidates{
      count
      rows{
        maxClinicalStage
        drug{id name drugType maximumClinicalStage mechanismsOfAction { rows { mechanismOfAction } } }
        diseases { disease { id name } }
      }
    }
  }
}"""

targets = {
    "EGFR": "ENSG00000146648",
    "ERBB2": "ENSG00000141736",
}

all_rows = []
for sym, ensg in targets.items():
    data = ot_query(query, {"ensgId": ensg})
    for row in data["target"]["drugAndClinicalCandidates"]["rows"]:
        drug = row["drug"]
        moa = drug.get("mechanismsOfAction") or {}
        moa_first = (moa.get("rows") or [{}])[0].get("mechanismOfAction")
        first_disease = (row.get("diseases") or [{}])[0].get("disease") or {}
        all_rows.append({
            "target": sym,
            "drug": drug["name"],
            "drug_type": drug["drugType"],
            : row[],
            : drug[] == ,
            : first_disease.get(, ),
            : moa_first,
        })

df = pd.DataFrame(all_rows)
df.to_csv(, index=)
(df.head().to_string(index=))

Key Parameters

Parameter	Module	Default	Range / Options	Effect
page.size	Associations	10	1–10000	Records per page
page.index	Associations	0	0–N	Page index for pagination
orderByScore	Associations	"score"	"score", component IDs	Sort associations by score
datasourceIds	Evidence	all sources	list of datasource IDs	Filter evidence by source
enableIndirect	Evidence	false	true/false	Include child disease evidence
entityNames	Search	all	["target"], ["disease"]	Filter search entity type

Best Practices

1. Use EFO IDs for diseases: Disease names vary; always use the search query to get the canonical EFO ID before running association queries to avoid name-matching issues.

2. Paginate for full result sets: Default page size is 10; use page.size: 10000 for complete results, but be aware this can return large payloads.

3. Filter by datatypeScores: For genetic target validation, filter on genetic_association subscore > 0.1; for drug repurposing, prioritize known_drug subscore.

4. Use enableIndirect: true in evidence queries to include evidence for disease subtypes (child terms in EFO hierarchy).

5. Cache GraphQL responses: Open Targets data updates quarterly; cache responses during analysis to avoid redundant API calls.

Common Recipes

Recipe: Disease Name to EFO ID

When to use: Resolve a disease name to the EFO ID needed for association queries.

import requests

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

query = """
query($q: String!) {
  search(queryString: $q, entityNames: ["disease"]) {
    hits { id name score }
  }
}"""
r = requests.post(OT_URL, json={"query": query, "variables": {"q": "breast cancer"}})
for hit in r.json()["data"]["search"]["hits"][:5]:
    print(f"{hit['id']}: {hit['name']} (score={hit['score']:.3f})")

Recipe: Target Tractability Assessment

When to use: Assess whether a target is tractable for small molecules, antibodies, or PROTACs.

import requests

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

query = """
query($ensgId: String!) {
  target(ensemblId: $ensgId) {
    approvedSymbol
    tractability { label modality value }
  }
}"""
r = requests.post(OT_URL, json={"query": query, "variables": {"ensgId": "ENSG00000141510"}})
t = r.json()["data"]["target"]
print(f"Tractability for {t['approvedSymbol']}:")
for tr in t.get("tractability", []):
    if tr["value"]:
        print(f"  [{tr['modality']}] {tr['label']}")

Recipe: Approved Drugs for a Disease

When to use: Find all approved drugs for a disease with phase 4 evidence.

import requests, pandas as pd

OT_URL = "https://api.platform.opentargets.org/api/v4/graphql"

query = """
query($efoId: String!) {
  disease(efoId: $efoId) {
    name
    drugAndClinicalCandidates { count rows {
      maxClinicalStage
      drug { name maximumClinicalStage drugType }
    }}
  }
}"""
r = requests.post(OT_URL, json={"query": query, "variables": {"efoId": "EFO_0000305"}})
data = r.json()["data"]["disease"]
approved = [row for row in data["drugAndClinicalCandidates"]["rows"] if row["drug"]["maximumClinicalStage"] == "PHASE_4"]
print(f"Approved drugs for {data['name']}: {len(approved)}")
for row in approved[:5]:
    print(f"  {row['drug']['name']} ({row['drug']['drugType']})  maxStage={row['maxClinicalStage']}")

Troubleshooting

Problem	Cause	Solution
HTTP 400 with GraphQL error	Malformed query or invalid field name	Check query against GraphQL schema at https://api.platform.opentargets.org/api/v4/graphql
Empty rows in associations	EFO ID not recognized	Use search query to find correct EFO ID
Target not found	Gene symbol vs Ensembl ID mismatch	Use search query first to resolve Ensembl ID
Slow query for large result set	page.size too large	Cap at 500 rows; paginate with multiple requests
Missing tractability data	Target not assessed	Not all targets have tractability; check tractability field is non-null
drugAndClinicalCandidates empty	No drug-target evidence in ChEMBL	Use chembl-database-bioactivity for preclinical compound activity

Related Skills

• chembl-database-bioactivity — Bioactivity IC50/Ki data for compounds against targets
• clinicaltrials-database-search — Detailed clinical trial information for drugs found via Open Targets
• ensembl-database — Ensembl IDs and variant annotations needed as input to Open Targets queries
• string-database-ppi — Protein-protein interaction networks to contextualize target biology

References

• Open Targets Platform — Interactive target-disease browser
• Open Targets GraphQL API documentation — Query reference and schema
• GraphQL playground — Interactive query builder
• Open Targets data sources — Evidence types and scoring methodology