EZH2 enhancer of zeste 2 polycomb repressive complex 2 subunit
ENSG00000106462 · protein coding · Open Targets profile
Catalytic subunit of the PRC2/EED-EZH2 complex, a Polycomb group (PcG) complex that methylates 'Lys-9' (H3K9me) and 'Lys-27' (H3K27me) of histone H3, leading to transcriptional repression of the affected target gene (PubMed:14532106, PubMed:15225548, PubMed:15385962, PubMed:16618801, PubMed:16936726, PubMed:17344414, PubMed:22323599, PubMed:24474760, PubMed:26581166, PubMed:30026490, PubMed:30923826). Able to mono-, di- and trimethylate 'Lys-27' of histone H3 to form H3K27me1, H3K27me2 and H3K27me3, respectively (PubMed:15231737, PubMed:17210787, PubMed:18285464, PubMed:22323599, PubMed:30923826). Displays a preference for substrates with less methylation, loses activity when progressively more methyl groups are incorporated into H3K27, H3K27me0 > H3K27me1 > H3K27me2 (PubMed:22323599, PubMed:30923826). Compared to EZH1-containing complexes, it is more abundant in embryonic stem cells and plays a major role in forming H3K27me3, which is required for embryonic stem cell identity and proper differentiation (PubMed:19026781). The PRC2/EED-EZH2 complex may also serve as a recruiting platform for DNA methyltransferases, thereby linking two epigenetic repression systems (PubMed:16357870, PubMed:17200670). Genes repressed by the PRC2/EED- EZH2 complex include HOXC8, HOXA9, MYT1, CDKN2A and retinoic acid target genes (PubMed:16179254, PubMed:18086877, PubMed:20935635). EZH2 can also methylate non-histone proteins such as the transcription factor GATA4 and the nuclear receptor RORA (PubMed:23063525). Regulates the circadian clock via histone methylation at the promoter of the circadian genes (PubMed:16717091). Essential for the CRY1/2-mediated repression of the transcriptional activation of PER1/2 by the CLOCK- BMAL1 heterodimer; involved in the di and trimethylation of 'Lys-27' of histone H3 on PER1/2 promoters which is necessary for the CRY1/2 proteins to inhibit transcription (By similarity). {ECO:0000250|UniProtKB:Q61188, ECO:0000269|PubMed:14532106, ECO:0000269|PubMed:15225548, ECO:0000269|PubMed:15231737, ECO:0000269|PubMed:15385962, ECO:0000269|PubMed:16179254, ECO:0000269|PubMed:16357870, ECO:0000269|PubMed:16618801, ECO:0000269|PubMed:16717091, ECO:0000269|PubMed:16936726, ECO:0000269|PubMed:17200670, ECO:0000269|PubMed:17210787, ECO:0000269|PubMed:17344414, ECO:0000269|PubMed:18086877, ECO:0000269|PubMed:18285464, ECO:0000269|PubMed:19026781, ECO:0000269|PubMed:20935635, ECO:0000269|PubMed:22323599, ECO:0000269|PubMed:23063525, ECO:0000269|PubMed:24474760, ECO:0000269|PubMed:26581166, ECO:0000269|PubMed:30026490, ECO:0000269|PubMed:30923826}.
Each band is a group of drugs. It runs from the kind of drug on the left to the furthest stage that drug has reached in any disease on the right. Thicker bands mean more drugs.
Approved bands are highlighted. Withdrawn means the drug was pulled from the market or from development. A combined phase counts as the later one (Phase 1/2 is shown as Phase 2). Hover a band for the drug names. Source: Open Targets Platform, fetched live.
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
- PROTAC
- Literature, UniProt Ubiquitination, Database Ubiquitination, Small Molecule Binder
gnomAD loss of function constraint: o/e 0.18292999267578125 (upper bound 0.2712700068950653). 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 44 registry trials, updated in the last three years, of the most advanced drugs against EZH2 (tazemetostat, tazemetostat hydrobromide), ranked by Phase 2+ trials. Live from ClinicalTrials.gov.
- Jennifer E AmengualSWOG Cancer Research Network · 1 of 2 trials Phase 2+
- Bin YangHutchison Medipharma Limited · 1 of 1 trials Phase 2+
- Clémentine SarkozyInstitut Gustave Roussy Cancer Campus Grand Paris · 1 of 1 trials Phase 2+
- Daniel S ShinMichael E. DeBakey VA Medical Center, Houston, TX · 1 of 1 trials Phase 2+
- Donald W ParsonsChildren's Oncology Group · 1 of 1 trials Phase 2+
- Franck MorshhauserCentre Régional Hospitalier de Lille · 1 of 1 trials Phase 2+
- Joanne LagmayUniversity of Florida · 1 of 1 trials Phase 2+
- Junning CaoShanghai Cancer Center · 1 of 1 trials Phase 2+
- Ki ChungPrisma Health · 1 of 1 trials Phase 2+
- Loic YsebaertIUCT Oncopole de Toulouse · 1 of 1 trials Phase 2+
- Maha H HussainUniversity Health Network Princess Margaret Cancer Center LAO · 1 of 1 trials Phase 2+
- Martin E GleaveUniversity of British Columbia · 1 of 1 trials Phase 2+
- Ramez N EskanderNRG Oncology · 1 of 1 trials Phase 2+
- Reem KarmaliNorthwestern University · 1 of 1 trials Phase 2+
- Sarah RutherfordWeill Medical College of Cornell University · 1 of 1 trials Phase 2+
Registry trials of tazemetostat, tazemetostat hydrobromide 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; 26 of 41 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. 3 trials list no sites and are left out. Source: ClinicalTrials.gov, fetched live.
21 trials of drugs against EZH2 were stopped early
Terminated, withdrawn and suspended interventional trials of tazemetostat, tazemetostat hydrobromide, GSK2816126, 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 21 most recent of 21.
- terminated · 2026-11-10 · National Cancer Institute (NCI) · Tazemetostat Hydrobromide“Withdrawal of tazemetostat supply led to early study closure.”
- terminated · 2026-10-28 · Epizyme, Inc. · Tazemetostat“Sponsor decision; no additional participant enrollment was anticipated.”
- terminated · 2026-04-17 · University of Alabama at Birmingham · Tazemetostat“Ipsen, drug company requested all studies using the drug Taxemetostat be terminated due to increased risk of secondary malignancies in subjects.”
- terminated · 2026-04-16 · Epizyme, Inc. · Tazemetostat“Ipsen decided to discontinue all active tazemetostat clinical trials.”
- terminated · 2026-04-02 · Weill Medical College of Cornell University · Tazemetostat“Low accrual”
- withdrawn · 2026-04-01 · Eric Jacobsen, MD · Tazemetostat“Ipsen requested a temporary closure due to a safety concern.”
- terminated · 2026-03-17 · Prisma Health-Upstate · Tazemetostat“Ipsen has discontinued all active tazemetostat clinical trials and expanded access programs due to the emergence of a clinically unfavorable benefit risk profile for tazemetostat in combination with lenalidomide and rituximab.”
- terminated · 2026-03-10 · Epizyme, Inc. · Tazemetostat“The study was terminated early as Sponsor decided to discontinue the development of tazemetostat in metastatic castration resistant prostate cancer and the primary endpoint was not met for this study. There were no safety concerns.”
- withdrawn · 2026-01-30 · Epizyme, Inc. · Tazverik (Tazemetostat)“Never started”
- suspended · 2026-01-21 · City of Hope Medical Center · Tazemetostat“Pending Interim Analysis”
- terminated · 2026-01-07 · Epizyme, Inc. · Tazemetostat“FDA and Ipsen alignelment: Due to unfeasibility and the resulting inability to meet the required enrolment targets. No safety concerns”
- terminated · 2024-03-25 · Epizyme, Inc. · Tazemetostat“Decision to terminate EZH-1401 was solely due to company business decision.”
- terminated · 2024-02-21 · Washington University School of Medicine · Tazemetostat“Ipsen bought out Epizyme”
- withdrawn · 2023-09-22 · Edwin Posadas, MD · matched by the registry's drug synonyms“PI voluntarily closed the study.”
- withdrawn · 2023-08-15 · Epizyme, Inc. · Tazemetostat“Epizyme Inc. has revised the Tazemetostat development strategy and made the decision to terminate the hematological malignancies basket trial.”
- withdrawn · 2023-07-07 · Jacob Soumerai, MD · TAZEMETOSTAT“Termination of Zandelisib clinical development globally”
- withdrawn · 2023-05-31 · City of Hope Medical Center · Tazemetostat“Feasibility”
- withdrawn · 2023-05-18 · Dana-Farber Cancer Institute · matched by the registry's drug synonyms“On hold”
- withdrawn · 2021-11-22 · Loma Linda University · Tazemetostat“FDA recommendation cited safety issues”
- terminated · 2020-02-25 · GlaxoSmithKline · GSK2816126“The maximal dose and schedule attained with GSK2816126 has shown insufficient evidence of clinical activity, and does not justify further clinical investigation”
- withdrawn · 2020-02-07 · National Cancer Institute (NCI) · Tazemetostat“Other - Drug Manufacturer decision to close study”
Paediatric incentives and obligations for EZH2's drugs
For tazemetostat, tazemetostat hydrobromide, GSK2816126: 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: yes · EZH2 is on the list. Membership alone neither requires nor waives a pediatric study.Rule: 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: yes · EMEA-003055-PIP02-23 (tazemetostat, Treatment of follicular lymphoma): W: decision granting a waiver in all age groups for all conditions or indications, 25 Jul 2023Rule: An EMA PIP decision (agreement, modification or waiver) lists the drug as its active substance, exact name. Source: EMA EMEA-003055-PIP02-23, 2026-11-11
- EU orphan designation: yes · EU/3/18/2004 withdrawn 21 Mar 2018: Treatment of diffuse large B-cell lymphoma; EU/3/18/2006 withdrawn 21 Mar 2018: Treatment of malignant mesothelioma; EU/3/18/2005 positive 21 Mar 2018: Treatment of follicular lymphomaRule: 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 tazemetostat, tazemetostat hydrobromide, gsk2816126Rule: 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: yes · Tazemetostat [Tazverik], 23 Jan 2020: Treatment of adults and pediatric patients aged 16 years and older with metastatic or locally advanced epithelioid sarcoma not eligible for complete resectionRule: FDA's Pediatric Oncology Drug Approvals table names the drug. Source: FDA Pediatric Oncology Drug Approvals (content current as of 2026-03-03), 2026-11-11
- Registered studies open to children: yes · 6 interventional studies of tazemetostat, tazemetostat hydrobromide, gsk2816126 include patients under 18; 3 are 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, 2026-11-11
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 3 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 |
|---|---|---|---|---|
| TAZEMETOSTAT | Small molecule | approval | follicular lymphoma, neoplasm, rhabdoid tumor, mesothelioma, extraskeletal myxoid chondrosarcoma, Ewing sarcoma, malignant myoepithelioma, rhabdoid tumor of the kidney, +41 more | Open Targets · ChEMBL |
| TAZEMETOSTAT HYDROBROMIDE | Small molecule | approval | follicular lymphoma, sarcoma, neoplasm | Open Targets · ChEMBL |
| GSK2816126 | Small molecule | phase 1 | prostate cancer, non-Hodgkin lymphoma, plasma cell myeloma, follicular lymphoma, diffuse large B-cell lymphoma | Open Targets · ChEMBL |