HDAC inhibitors
The short answer
HDAC inhibitors have been approved for blood cancers for about 20 years, but the class only proved itself alongside immunotherapy in 2026. Seven molecules in our dataset carry approvals in the US, EU, China, Japan or Taiwan, mostly for lymphoma and myeloma; entinostat and tucidinostat are approved for HR+ breast cancer in China, and givinostat for Duchenne muscular dystrophy. The race that matters now is HDAC plus PD-1. HUYABIO's HBI-8000-303 improved progression-free survival in advanced melanoma at ESMO 2026 (11.7 vs 7.4 months, HR 0.73), but grade 3/4 treatment-related side effects rose from 17.9% to 54.8%. The next test is harder: Taiwan's Anbogen is running ABT-301 with tislelizumab and bevacizumab in MSS colorectal cancer, a tumor type where most immunotherapy combinations have failed.
Phase 3 readouts
| Study | Readout | Median PFS (months) | PFS HR | Grade 3/4 TRAEs | Dose reductions |
|---|---|---|---|---|---|
| HBI-8000-303 | ESMO 2026 2026-10-23 | 11.7 vs 7.4 | 0.73 | 54.8% vs 17.9% | 38% |
HBI-8000 + nivolumab vs placebo + nivolumab; dose reductions refer to HBI-8000. Sponsor-reported results; overall survival data were immature.
Pipeline · 20
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| Belinostat / Beleodaq | Acrotech Biopharma | United States | Approved US accelerated approval (2014): adults with relapsed or refractory PTCL. Confirmatory benefit requirement remains in cited label. | Relapsed/refractory PTCL | — | — | Beleodaq manufacturer label on DailyMed FDA belinostat risk review |
| Entinostat / SNDX-275 / MS-275 | Syndax; Taizhou EOC Pharma / Edding Genor (China) | United States; China | Approved China approved (April 2024): HR+/HER2− locally advanced or metastatic breast cancer progressing after endocrine therapy, with an aromatase inhibitor. Syndax has deprioritised development. | HR+/HER2− advanced breast cancer | aromatase inhibitor | — | Syndax 2025 Form 10-K Edding Genor annual report 2025 Syndax entinostat program page |
| Givinostat / Duvyzat | Italfarmaco / ITF Therapeutics | Italy; United States (commercial subsidiary) | Approved US approved (2024): DMD age ≥6 years. EU conditional approval (2025): ambulant DMD age ≥6 years with concomitant corticosteroids. | Duchenne muscular dystrophy | corticosteroids (EU) | — | FDA Duvyzat approval EMA Duvyzat EPAR FDA givinostat integrated review |
| Panobinostat / Farydak | pharmaand GmbH (EU); Secura Bio (former US NDA holder) | Austria; United States (former US holder) | Approved EU approved (2015): relapsed/refractory multiple myeloma with bortezomib + dexamethasone after at least two prior regimens. US approval withdrawn 2022-03-24. | Relapsed/refractory multiple myeloma | bortezomib + dexamethasone | — | EMA Farydak EPAR FDA withdrawn cancer accelerated approvals FDA Farydak withdrawal notice FDA panobinostat pharmacology review |
| Romidepsin / Istodax | Bristol Myers Squibb / Celgene | United States | Approved US approved (2009): adult CTCL after at least one systemic therapy. US PTCL indication withdrawn 2021-07-30. | CTCL | — | — | Istodax US prescribing information FDA withdrawn cancer accelerated approvals FK228 primary pharmacology study |
| Tucidinostat / chidamide / Epidaza | Chipscreen Biosciences | China | Approved China: PTCL (2014), HR+/HER2− advanced breast cancer with endocrine therapy (2019), untreated MYC/BCL2-positive DLBCL + R-CHOP (2024). Japan: ATL and PTCL (2021). Taiwan: breast cancer + exemestane (2023). | PTCL; HR+/HER2− breast cancer; MYC/BCL2-positive DLBCL; ATL | endocrine therapy / R-CHOP (China); exemestane (Taiwan) | — | Chipscreen chidamide product page Chipscreen DLBCL approval announcement Chipscreen DEB phase 3 publication announcement Original chidamide CS055/HBI-8000 pharmacology study |
| Vorinostat / Zolinza | Merck & Co. | United States | Approved US approved (2006): cutaneous manifestations of progressive, persistent or recurrent CTCL on or after two systemic therapies. | CTCL | — | — | Zolinza US prescribing information |
| Abexinostat / PCI-24781 | Xynomic Pharmaceuticals | United States; China | Phase 3 Phase 3 RENAVIV, recruiting: abexinostat + pazopanib in advanced/metastatic RCC (NCT03592472). | Advanced/metastatic renal cell carcinoma | pazopanib | NCT03592472 | Xynomic S-1 hosted by issuer Abexinostat pivotal phase 2 original report A Study of Pazopanib With or Without Abexinostat in Patients With Locally Advanced or Metastatic Renal Cell Carcinoma (RENAVIV) |
| HBI-8000 / tucidinostat / chidamide | HUYABIO International | United States | Phase 3 Phase 3 advanced melanoma + nivolumab; HBI-8000-303 (NCT04674683). Registry: active, not recruiting. Not approved for melanoma. | Advanced melanoma | nivolumab | NCT04674683 | Original chidamide CS055/HBI-8000 pharmacology study HUYABIO ESMO 2026 phase 3 announcement Study Comparing Investigational Drug HBI-8000 + Nivolumab vs. Placebo + Nivolumab in Patients With Advanced Melanoma |
| Purinostat mesylate | Chengdu Zenitar Biomedical Technology | China | Phase 3 Phase 3, recruiting: purinostat mesylate vs selinexor in relapsed/refractory DLBCL (NCT07011056). | Relapsed/refractory DLBCL | — | NCT07011056 | Purinostat preclinical and first-in-human original research A Phase III Clinical Study of Purinostat Mesylate for Injection in Patients With Diffuse Large B-cell Lymphoma |
| Tinostamustine / EDO-S101 | Knoa Pharma; GCAR (platform sponsor) | United States | Phase 2/3 · platform Phase 2/3 GBM AGILE evaluation (NCT03970447), recruiting platform; drug-arm enrolment corroborated by Knoa/GCAR announcement. | Glioblastoma (GBM AGILE platform) | — | NCT03970447 | Knoa pipeline Knoa LSX pipeline announcement Knoa and GCAR GBM AGILE tinostamustine enrolment A Trial to Evaluate Multiple Regimens in Newly Diagnosed and Recurrent Glioblastoma |
| ABT-301 / MPT0E028 | Anbogen Therapeutics | Taiwan | Phase 1/2 Phase 1b/2 (registry phases 1/2), recruiting; pMMR/non-MSI-H advanced/metastatic CRC + tislelizumab + bevacizumab (NCT07244705). | pMMR/non-MSI-H advanced/metastatic colorectal cancer | tislelizumab + bevacizumab | NCT07244705 | Anbogen clinical update at Chang Gung Medical Week A Study of ABT-301 Plus Tislelizumab With Bevacizumab in pMMR/Non-MSI-H Locally Advanced or mCRC |
| Domatinostat / 4SC-202 | 4SC (originator); Healx USA (partner); Moffitt (trial sponsor) | Germany; United States | Phase 1/2 Phase 1/2, recruiting: domatinostat + sirolimus for relapsed/refractory sarcoma and osteosarcoma (NCT07725380). | Relapsed/refractory sarcoma; osteosarcoma | sirolimus | NCT07725380 | 4SC domatinostat discontinuation 4SC partnered products Domatinostat With Sirolimus for Relapsed, Refractory Sarcoma and Osteosarcoma |
| Fimepinostat / CUDC-907 | Curis (originator); UCLA (current selected trial sponsor) | United States | Phase 2 Phase 2 Cushing disease trial, recruiting (NCT05971758); investigator-sponsored. Curis does not prioritise company clinical development. | Cushing disease | — | NCT05971758 | Curis fimepinostat program Curis pipeline Fimepinostat, Combination HDAC and Pi3-kinase Inhibitor Tumor-Directed Therapy for Cushing Disease |
| Ivaltinostat / CG200745 | CG Pharmaceuticals (US licensee; formerly licensed from CG Invites) | United States | Phase 1/2 Phase 1b/2 metastatic pancreatic adenocarcinoma maintenance + capecitabine (NCT05249101), active not recruiting. | Metastatic pancreatic adenocarcinoma maintenance | capecitabine | NCT05249101 | CG Pharmaceuticals ASCO GI announcement Ivaltinostat phase 1b original conference abstract A Study of Ivaltinostat Plus Capecitabine or Capecitabine in Metastatic Pancreatic Adenocarcinoma |
| JBI-802 | Jubilant Therapeutics | United States | Phase 1/2 Phase 1/2 MPN and MDS/MPN with thrombocytosis, recruiting (NCT07612280). | MPN; MDS/MPN with thrombocytosis | — | NCT07612280 | Jubilant-issued SOHO 2026 JBI-802 announcement Phase 1/ Phase 2 Study to Assess Safety and Efficacy of Orally Administered JBI-802 in Subjects With Myeloproliferative Neoplasms (MPN) and Myelodysplastic/Myeloproliferative Neoplasms (MDS/MPN) With Thrombocytosis |
| Ricolinostat / ACY-1215 | Regenacy (DPN developer); Acetylon (originator); Dana-Farber (CLL trial sponsor) | United States | Phase 2 completed; Phase 1 ongoing Highest selected phase: completed Phase 2 DPN (NCT03176472). Ongoing selected study: Phase 1 CLL, active not recruiting (NCT02787369). | CLL; completed DPN study | — | NCT02787369 | Regenacy phase 2 DPN trial publication ACY-1215 in Combination With BCR Pathway Inhibitors in Relapsed CLL Ricolinostat in Patients With Painful Diabetic Peripheral Neuropathy ACY-1215 (Ricolinostat) in Combination With Pomalidomide and Low-dose Dex in Relapsed-and-Refractory Multiple Myeloma |
| Zabadinostat / CXD101 | Celleron Therapeutics (historical developer); CUHK / Stephen Chan Lam (trial sponsor) | United Kingdom; Hong Kong (investigator study) | Phase 2 Phase 2 HCC + geptanolimab (NCT05873244), active not recruiting. | Hepatocellular carcinoma | geptanolimab | NCT05873244 | CAROSELL original phase 2 paper CXD101 in Immunotherapy-related Liver Cancer Open-Label, Phase 1 Clinical Trial of Neoadjuvant Nogapendekin Alfa Inbakicept, Sotevtamab, and Zabadinostat in Combination With Gemcitabine and Nab-Paclitaxel for Participants With Borderline Resectable or Locally Advanced Pancreatic Cancer |
| Nanatinostat / VRx-3996 | Viracta Therapeutics (ceased operations) | United States | Stopped / historical Historical Phase 2 NAVAL-1 EBV-positive lymphoma (NCT05011058): terminated. Viracta no longer operating. | EBV-positive lymphoma | — | NCT05011058 | Viracta-issued wind-down announcement Viracta current official website An Open-Label Phase 2 Trial of Nanatinostat Plus Valganciclovir in Patients With EBV+ Relapsed/Refractory Lymphomas |
| Resminostat / Kinselby | 4SC | Germany | Stopped / historical EU CHMP negative opinion (2025); 4SC ceased development and commercialisation. Historical pivotal RESMAIN study (NCT02953301). | CTCL (historical RESMAIN) | — | NCT02953301 | 4SC negative CHMP opinion and cessation 4SC resminostat mechanism Resminostat for Maintenance Treatment of Patients With Advanced Stage Mycosis Fungoides (MF) or Sézary Syndrome (SS) |
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FAQ
Which HDAC inhibitors are approved?
As of 2026-11-01, the 7 molecules with approval records in our dataset are Belinostat, Entinostat, Givinostat, Panobinostat, Romidepsin, Tucidinostat, Vorinostat. Approval and withdrawal status varies by indication and region, as shown in the table. Panobinostat's US approval was withdrawn in 2022; status differs by country, as shown in the table.
Which HDAC inhibitor companies are in Phase 3?
As of 2026-11-01, this dataset lists 3 selected Phase 3 programs: Xynomic Pharmaceuticals — Abexinostat; HUYABIO International — HBI-8000; Chengdu Zenitar Biomedical Technology — Purinostat mesylate. Tinostamustine is listed separately as a Phase 2/3 platform evaluation.
Which Taiwanese companies develop HDAC inhibitors?
Anbogen Therapeutics is the leading Taiwanese developer. Its oral HDAC inhibitor ABT-301 is in a Phase 1b/2 trial with tislelizumab and bevacizumab in pMMR / non-MSI-H metastatic colorectal cancer (NCT07244705); the company has selected 150 mg once daily for the next stage and plans to start Part 2 by the end of 2026.
What is the latest HDAC + PD-1 data in this dataset?
On 2026-10-23, HUYABIO reported HBI-8000-303 at ESMO 2026: median PFS 11.7 vs 7.4 months; HR 0.73. Grade 3/4 treatment-related adverse events: 54.8% vs 17.9%; HBI-8000 dose reductions: 38%. Overall survival data were immature. These are sponsor-reported results.