AHR aryl hydrocarbon receptor
ENSG00000106546 · protein coding · Open Targets profile
Ligand-activated transcription factor that enables cells to adapt to changing conditions by sensing compounds from the environment, diet, microbiome and cellular metabolism, and which plays important roles in development, immunity and cancer (PubMed:23275542, PubMed:30373764, PubMed:32818467, PubMed:7961644). Upon ligand binding, translocates into the nucleus, where it heterodimerizes with ARNT and induces transcription by binding to xenobiotic response elements (XRE) (PubMed:23275542, PubMed:30373764, PubMed:7961644). Regulates a variety of biological processes, including angiogenesis, hematopoiesis, drug and lipid metabolism, cell motility and immune modulation (PubMed:12213388). Xenobiotics can act as ligands: upon xenobiotic- binding, activates the expression of multiple phase I and II xenobiotic chemical metabolizing enzyme genes (such as the CYP1A1 gene) (PubMed:7961644, PubMed:33193710). Mediates biochemical and toxic effects of halogenated aromatic hydrocarbons (PubMed:34521881, PubMed:7961644). Next to xenobiotics, natural ligands derived from plants, microbiota, and endogenous metabolism are potent AHR agonists (PubMed:18076143). Tryptophan (Trp) derivatives constitute an important class of endogenous AHR ligands (PubMed:32818467, PubMed:32866000). Acts as a negative regulator of anti-tumor immunity: indoles and kynurenic acid generated by Trp catabolism act as ligand and activate AHR, thereby promoting AHR-driven cancer cell motility and suppressing adaptive immunity (PubMed:32818467). Regulates the circadian clock by inhibiting the basal and circadian expression of the core circadian component PER1 (PubMed:28602820). Inhibits PER1 by repressing the CLOCK-BMAL1 heterodimer mediated transcriptional activation of PER1 (PubMed:28602820). The heterodimer ARNT:AHR binds to the dioxin response element (DRE) of target gene promoters and activates their transcription (PubMed:28602820). {ECO:0000269|PubMed:23275542, ECO:0000269|PubMed:28602820, ECO:0000269|PubMed:30373764, ECO:0000269|PubMed:32818467, ECO:0000269|PubMed:32866000, ECO:0000269|PubMed:33193710, ECO:0000269|PubMed:34521881, ECO:0000269|PubMed:7961644, ECO:0000303|PubMed:12213388, ECO:0000303|PubMed:18076143}.
Each row is a cancer, strongest overall evidence first. The two dots show how strong the inherited (germline) and tumour-mutation (somatic) evidence is; the line between them is the gap.
Scores run from 0 (no evidence) to 1 (strongest). A missing dot at 0 means Open Targets holds no evidence of that kind. Source: Open Targets Platform, fetched live.
Tractability
- Small molecule
- Approved Drug, Structure with Ligand, High-Quality Ligand, Druggable Family
- PROTAC
- Literature, Database Ubiquitination, Half-life Data, Small Molecule Binder
gnomAD loss of function constraint: o/e 0.46057000756263733 (upper bound 0.5995500087738037). Low values mean loss of function is poorly tolerated, a safety flag for inhibition.
Who runs trials of these drugs
Principal investigators and study chairs on 20 registry trials, updated in the last three years, of the most advanced drugs against AHR (tapinarof), ranked by Phase 2+ trials. Live from ClinicalTrials.gov.
- Diana VillalobosDermavant Sciences, Inc. · 4 of 4 trials Phase 2+
- Victoria ButnersDermavant Sciences GmbH · 3 of 3 trials Phase 2+
- David RosmarinDermatology · 1 of 1 trials Phase 2+
- Michael McLaughlinDermavant Sciences, Inc. · 1 of 1 trials Phase 2+
- Raymond ChoUniversity of California, San Francisco · 1 of 1 trials Phase 2+
- Steven R FeldmanWake Forest University Health Sciences · 1 of 1 trials Phase 2+
- Natalie YantovskiySun Pharmaceuticals Industries, Inc. · 0 of 1 trials Phase 2+
- Paras VakhariaNorthwestern University · 0 of 1 trials Phase 2+
Registry trials of tapinarof updated in the last three years, counted by the country group of their listed sites. A trial with sites in several groups counts in each; 10 of 19 have all sites in one country.
Site counts are not patients per country, and trials registered only outside ClinicalTrials.gov are not covered. Where sites are is a fact about the record, not a judgement of its quality. Europe is the EU and EEA, the UK and Switzerland. 1 trials list no sites and are left out. Source: ClinicalTrials.gov, fetched live.
2 trials of drugs against AHR were stopped early
Terminated, withdrawn and suspended interventional trials of tapinarof, newest update first, live from ClinicalTrials.gov. Each reason is quoted exactly as the registry gives it; we do not sort reasons into safety, efficacy or business. Dates are the last registry update. Showing the 2 most recent of 2.
- withdrawn · 2017-12-07 · GlaxoSmithKline · matched by the registry's drug synonyms“The decision not to progress the planned Phase 3 studies is a business decision based on the need to prioritise and focus resources within GSK.”
- withdrawn · 2017-11-29 · GlaxoSmithKline · matched by the registry's drug synonyms“The whole project was discontinued within GSK, hence this study was cancelled before enrolment.”
Paediatric incentives and obligations for AHR's drugs
For tapinarof: what EMA and FDA publish about paediatric plans, orphan status and pediatric approvals, and how many registered studies take children. Each line is a yes, no or not published fact from the record linked under it; none of it is a forecast.
- FDA pediatric target list: no · AHR is not on the listRule: Target is on FDA's Pediatric Molecular Target List (relevant targets). Source: FDA Pediatric Molecular Target List (Listed as February 2026 on the FDA Pediatric Oncology page; the file served is 9.7.22_the_relevant_molecular_target_list.xlsx, whose Summary of Changes sheet is headed 'SEPTEMBER 2022 UPDATE' (footnote date 2022-09-01)), 2026-11-11
- EU paediatric investigation plan: no · No EMA paediatric investigation plan decision names tapinarofRule: An EMA PIP decision (agreement, modification or waiver) lists the drug as its active substance, exact name. Source: EMA data download (dated snapshot), 2026-11-11
- EU orphan designation: no · No EU orphan designation names tapinarofRule: An EU orphan designation lists the drug as its active substance (exact name) or belongs to a medicine that does; withdrawn and expired designations are listed with their status. Source: EMA data download (dated snapshot), 2026-11-11
- Authorised in the EU: no · EMA lists no centrally authorised medicine of tapinarofRule: An EMA medicine record lists the drug as its active substance or INN, exact name; national-only authorisations are not in this file. Source: EMA data download (dated snapshot), 2026-11-11
- FDA orphan designation: not published · FDA's orphan designation database turns away automated requests, so this app does not read it; search it by hand at the linkRule: Would be: an FDA orphan designation names the drug. Source: FDA orphan designations search
- FDA pediatric oncology approval: no · FDA's table lists no pediatric approval of tapinarofRule: FDA's Pediatric Oncology Drug Approvals table names the drug. Source: FDA Pediatric Oncology Drug Approvals (content current as of 2026-03-03), 2026-11-12
- Registered studies open to children: yes · 7 interventional studies of tapinarof include patients under 18; 1 is recruiting, not yet recruiting or activeRule: The registry's age group includes Child (birth to 17 years), which also counts studies that set no minimum age. Source: ClinicalTrials.gov search, 2026-11-12
Rare pediatric disease voucher. FDA, content current as of 29 Apr 2026: “As of February 3, 2026, enactment of the Consolidated Appropriations Act, 2026, the rare pediatric disease PRV program will sunset after September 30, 2029. FDA may not award any PRVs under this program after September 30, 2029.” Voucher sale prices are not shown here; they appear only as company-reported news. FDA: Rare Pediatric Disease Designation and Priority Review Voucher Programs
All 1 drugs and clinical candidates as a table
Each drug, stage and indication links to its Open Targets record, where the trials and approvals behind it are listed. Salt forms (for example a mesylate) are listed as Open Targets records them, as separate entries.
| Drug | Type | Highest stage | Indications | Source records |
|---|---|---|---|---|
| TAPINAROF | Small molecule | phase 4 | psoriasis vulgaris, psoriasis, atopic eczema, Palmoplantar keratoderma, cutaneous lupus erythematosus | Open Targets · ChEMBL |