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Purpose Effective second‐line chemotherapy options are limited in treating advanced biliary tract cancers (BTCs). Resminostat is an oral histone deacetylase inhibitor. Such inhibitors increase sensitivity to fluorouracil, the active form of S‐1. In the phase I study, addition of resminostat to S‐1 was suggested to have promising efficacy for pre‐treated BTCs. This study investigated the efficacy and safety of resminostat plus S‐1 in second‐line therapy for BTCs. Methods Patients were randomly assigned to receive resminostat or placebo (200 mg orally per day; days 1–5 and 8–12) and S‐1 group (80–120 mg orally per day by body surface area; days 1–14) over a 21‐day cycle. The primary endpoint was progression‐free survival (PFS). Secondary endpoints comprised overall survival (OS), response rate (RR), disease control rate (DCR), and safety. Results Among 101 patients enrolled, 50 received resminostat+S‐1 and 51 received placebo+S‐1. Median PFS was 2.9 months for resminostat+S‐1 vs. 3.0 months for placebo+S‐1 (HR: 1.154, 95% CI: 0.759–1.757, p = 0.502); median OS was 7.8 months vs. 7.5 months, respectively (HR: 1.049, 95% CI: 0.653–1.684, p = 0.834); the RR and DCR were 6.0% vs. 9.8% and 70.0% vs. 78.4%, respectively. Treatment‐related adverse events (TrAEs) of grade ≥ 3 occurring more frequently (≥10% difference) in the resminostat+S‐1 than in the placebo+S‐1 comprised platelet count decreased (18.0% vs. 2.0%) and decreased appetite (16.0% vs. 2.0%). Conclusions Resminostat plus S‐1 therapy improved neither PFS nor OS for patients with pre‐treated BTCs. Addition of resminostat to S‐1 was associated with higher incidence of TrAEs, but these were manageable (JapicCTI‐183883)., This randomized, placebo‐controlled, double‐blind study investigated the efficacy and safety of resminostat plus S‐1 as a second‐line therapy in patients with BTCs. This was the first randomized study to use S‐1, which is widely used in second‐line treatment for BTC patients in Japan, as an active comparator. The results showed that resminostat plus S‐1 prolonged neither PFS nor OS in comparison with placebo plus S‐1.

Drug-tolerant cells are mediators of acquired resistance. BIM-intron2 deletion polymorphism (BIM-del) is one of the mechanisms underlying the resistance to epidermal growth factor tyrosine kinase inhibitor (EGFR-TKI)-mediated apoptosis that induces drug tolerance. Here, we investigated whether resminostat, a histone deacetylase inhibitor, circumvents BIM-del-associated apoptosis resistance. The human EGFR-mutated non-small cell lung cancer (NSCLC) cell line PC-9 and its homozygous BIM-del-positive variant (PC-9 BIMi2- / -), established by editing with zinc finger nuclease, were used. In comparison with PC-9 cells, PC-9 BIMi2- / - cells were less sensitive to apoptosis mediated by EGFR-TKIs such as gefitinib and osimertinib. The combined use of resminostat and an EGFR-TKI preferentially induced the expression of the pro-apoptotic BIM transcript containing exon 4 rather than that containing exon 3, increased the level of pro-apoptotic BIM protein (BIMEL), and stimulated apoptosis in vitro. In a subcutaneous tumor model derived from PC-9 BIMi2- / - cells, gefitinib monotherapy decreased tumor size but retained residual lesions, indicative of the presence of tolerant cells in tumors. The combined use of resminostat and gefitinib increased BIMEL protein level and induced apoptosis, subsequently leading to the remarkable shrinkage of tumor. These findings suggest the potential of resminostat to circumvent tolerance to EGFR-TKIs associated with BIM deletion polymorphism. J. Med. Invest. 67 : 343-350, August, 2020.

Simple Summary Liver cancer is one of the most frequently occurring cancer types and one of the leading causes of cancer-related mortality globally. Despite of its constantly growing incidence, the efficacy of the current therapeutic interventions is limited. Metabolic and epigenetic aberrations are two distinct but mutually influential factors which contribute to the plasticity and adaptability of tumor cells to a hostile microenvironment, leading to high resilience and permissive conditions. This review offers the most up-to-date overview of the recently reported major metabolic dysregulations in liver cancer cells, the consequential epigenetic reprogramming, as well as the opportunity to explore the effect on metabolic competition and inhibition of immune cells in the tumor microenvironment. Finally, we discuss the potential therapeutic value of pharmaceutical inhibition of these essential pathways in combating liver cancer. Abstract Metabolic reprogramming and epigenetic changes have been characterized as hallmarks of liver cancer. Independently of etiology, oncogenic pathways as well as the availability of different energetic substrates critically influence cellular metabolism, and the resulting perturbations often cause aberrant epigenetic alterations, not only in cancer cells but also in the hepatic tumor microenvironment. Metabolic intermediates serve as crucial substrates for various epigenetic modulations, from post-translational modification of histones to DNA methylation. In turn, epigenetic changes can alter the expression of metabolic genes supporting on the one hand, the increased energetic demand of cancer cells and, on the other hand, influence the activity of tumor-associated immune cell populations. In this review, we will illustrate the most recent findings about metabolic reprogramming in liver cancer. We will focus on the metabolic changes characterizing the tumor microenvironment and on how these alterations impact on epigenetic mechanisms involved in the malignant progression. Furthermore, we will report our current knowledge about the influence of cancer-specific metabolites on epigenetic reprogramming of immune cells and we will highlight how this favors a tumor-permissive immune environment. Finally, we will review the current strategies to target metabolic and epigenetic pathways and their therapeutic potential in liver cancer, alone or in combinatorial approaches.

In hepatocellular carcinoma (HCC), blood platelets have been linked to tumor growth, epithelial-to-mesenchymal transition (EMT), extrahepatic metastasis and a limited therapeutic response to the multikinase inhibitor (MKi) sorafenib, the standard of care in advanced HCC for the last decade. Recent clinical data indicated an improved overall survival for sorafenib in combination with the HDAC inhibitor resminostat in a platelet count dependent manner. Here, the impact of platelets on the sorafenib and resminostat drug effects in HCC cells was explored. In contrast to sorafenib, resminostat triggered an anti-proliferative response in HCC cell lines independent of platelets. As previously described, platelets induced invasive capabilities of HCC cells, a prerequisite for extravasation and metastasis. Importantly, the resminostat/sorafenib drug combination, but not the individual drugs, effectively blocked platelet-induced HCC cell invasion. Exploration of the molecular mechanism revealed that the combined drug action led to a reduction of platelet-induced CD44 expression and to the deregulation of several other epithelial and mesenchymal genes, suggesting interference with cell invasion via EMT. In addition, the drug combination decreased phosphorylated ERK level, indicating inhibition of the mitogenic signaling pathway MEK/ERK. Taken together, the resminostat plus sorafenib combination counteracts platelet-mediated cancer promoting effects in HCC cells.

Background: Patients with advanced CTCL disease ((stage IIB–IVB) mycosis fungoides (MF) or Sezary syndrome (SS)) have a poor prognosis and suffer from profound symptom burden. These patients require systemic treatment. However, it is still a key challenge to achieve durable remissions with the available treatment options. CTCL is characterized by the presence of malignant clonal T-cells in the skin and/or blood, lymph nodes or visceral organs. Epigenetic alterations in malignant T cells are known to play a key role in the pathogenesis of the disease. Resminostat is an orally available HDAC-inhibitor, which induces changes in gene expression resulting in growth inhibition, modified cell differentiation and enhanced tumor immunogenicity. The purpose of the RESMAIN study is to investigate resminostat as maintenance treatment for patients with advanced stage mycosis fungoides (MF) or Sezary syndrome (SS) that have achieved disease control with systemic therapy. Methods: The RESMAIN study is a multicenter, double blind randomized, placebo controlled, prospective efficacy trial. Patients are randomized 1:1 to the resminostat and the placebo arm. Furthermore, patients are stratified according to their remission status and their disease stage immediately prior to the last systemic therapy. Patients will be treated until disease progression. Patients of the placebo arm have the option to receive resminostat treatment. In addition, exploratory biomarker analyses will be performed. Results: The study is conducted in 11 European countries at 51 sites and at 5 sites in Japan. The first patient was enrolled in January 2017. Recruitment was impacted by the COVID-19 pandemic but continued slowly in 2020 and is now in its final stage. The independent data safety monitoring committee (DSMB) recommended continuation of the ongoing RESMAIN study without modification after a pre-specified review of cumulative safety data of the first 50, 100, ,150 and 175 patients which had completed at least one treatment cycle. The poster will present an actual status update of the RESMAIN study. Conclusion and objectives: The primary objective is to determine if maintenance treatment with resminostat increases progression free survival (PFS) compared to placebo. As a key secondary end point the effect of resminostat on time to symptom worsening (TTSW) of pruritus compared to placebo will be assessed. Further secondary endpoints are TTP, TTNT, ORR, OS and HrQoL among others. To our knowledge, this is the first randomized study that investigates the potential of an HDAC inhibitor as maintenance therapy in advanced CTCL.

The combination of Resminostat (HDACi) and Ruxolitinib (JAKi) exerted cytotoxic effects and inhibited proliferation of CTCL cell lines (MyLa, SeAx) in previously published work. A xenograft tumor formation was produced by implanting the MyLa or SeAx cells on top of the chick embryo chorioallantoic membrane (CAM). The CAM assay protocol was developed to monitor the metastatic properties of CTCL cells and the effects of Resminostat and/or Ruxolitinib in vivo. In the spontaneous CAM assays, Resminostat and Ruxolitinib treatment inhibited the cell proliferation (p < 0.001) of MyLa and SeAx, and induced cell apoptosis (p < 0.005, p < 0.001, respectively). Although monotherapies reduced the size of primary tumors in the metastasis CAM assay, the drug combination exhibited a significant inhibition of primary tumor size (p < 0.0001). Furthermore, the combined treatment inhibited the intravasation of MyLa (p < 0.005) and SeAx cells (p < 0.0001) in the organs, as well as their extravasation to the liver (p < 0.0001) and lung (p < 0.0001). The drug combination also exerted a stronger inhibitory effect in migration (p < 0.0001) rather in invasion (p < 0.005) of both MyLa and SeAx cells. It further reduced p-p38, p-ERK, p-AKT, and p-STAT in MyLa cells, while it decreased p-ERK and p-STAT in SeAx cells in CAM tumors. Our data demonstrated that the CAM assay could be employed as a preclinical in vivo model in CTCL for pharmacological testing. In agreement with previous in vitro data, the combination of Resminostat and Ruxolitinib was shown to exert antitumor effects in CTCL in vivo., This research was funded by a PIE grant (PIE-202020E007) at B.C lab from Consejo Superior de Investigaciones Científicas (CSIC)-MCIU, the Ramon y Cajal Research Program (MCIU, RYC2018-024004-I) and a LA FUNDACIÓ D’ESTUDIS I RECERCA ONCOLÒGICA (FERO) grant (BFERO2021.03).

Purpose: Resminostat is an oral inhibitor of class I, IIB, and IV histone deacetylases. This phase I/II study compared the safety and efficacy of resminostat plus sorafenib versus sorafenib monotherapy as first-line therapy for advanced hepatocellular carcinoma (HCC). Experimental design: In phase I, resminostat (400 mg or 600 mg/day on days 1 to 5 every 14 days) was administered with sorafenib (800 mg/day for 14 days) to determine the recommended dose for phase II. In phase II, patients were randomized (1:1) to sorafenib monotherapy or resminostat plus sorafenib. The primary endpoint was time-to-progression (TTP). Results: Nine patients (3: 400 mg, 6: 600 mg) were enrolled in phase I, and the recommended dose of resminostat was determined to be 400 mg/day. Then 170 patients were enrolled in phase II. Median TTP/overall survival (OS) were 2.8/14.1 months with monotherapy versus 2.8/11.8 months with combination therapy (Hazard Ratio [HR]: 0.984, p = 0.925/HR: 1.046, p = 0.824). The overall incidence of adverse events was similar in both groups (98.8% versus 100.0%). However, thrombocytopenia ≥ Grade 3 was significantly more frequent in the combination therapy group (34.5% versus 2.4%, p

Resminostat is an oral hydroxamate inhibitor of class I, IIb, and IV histone deacetylases. S-1 is widely used to treat biliary tract cancer and pancreatic cancer in Japan. We performed a phase I study of resminostat combined with S-1 as second-line or later therapy in Japanese patients with biliary tract or pancreatic cancer. A total of 27 patients were enrolled. We determined the optimal regimen for resminostat/S-1 therapy in part 1, and investigated its safety and efficacy in part 2. In part 1, 17 patients were enrolled. One DLT (anorexia and stomatitis, respectively) occurred with each of regimens 2 and 3. In part 2, an additional 10 patients received regimen 3, which was selected in part 1. Regimen 3 was resminostat (200 mg/day on Days 1 to 5 and Days 8 to 12: 5 days on/2 days off) plus S-1 (80-120 mg/day according to body surface area on Days 1 to 14) repeated every 21 days. A total of 16 patients (13 with biliary tract cancer and 3 with pancreatic cancer) received regimen 3 and it was well tolerated. The most frequent treatment-related adverse events were thrombocytopenia and anorexia (11 patients each, 69%). The disease control rate was 81.3% (84.6% for biliary tract cancer and 66.7% for pancreatic cancer, respectively). Median progression-free survival was 3.1 months (5.5 and 2.3 months), while median overall survival was 8.8 months (10.2 and 4.7 months). In conclusion, regimen 3 was well tolerated by patients with pre-treated biliary tract or pancreatic cancer.

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer with increases in new cases being reported annually. Histopathologists have identified hepatic steatosis as a characteristic of a broad range of chronic liver diseases that are associated with the onset and development of HCC. In this context, epigenetic modifications may serve as precancerous factors predisposing normal cells to the initiation of carcinogenesis. This study demonstrated that hepatic tumorigenesis and differentiated adipocytes may modulate both global histone deacetylase (HDAC) expression and specific class I HDAC genes in the tumour microenvironment. The novel class I HDAC inhibitor Resminostat was shown to reduce the proliferation of HCC cells along with its specificity in targeting class I HDACs and oncogenes. The combined effect of Resminostat with several pharmaceutical agents such as Sorafenib, Cisplatin and Doxorubicin was also demonstrated. The inhibition of heat shock protein 90 (HSP90) has been demonstrated as a potential therapeutic option for HCC. In line with this, the specific HSP90 inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) was selected and it was found that the combination of Resminostat and 17-AAG may provide a "smart" clinical strategy for HCC patients by targeting cellular communication within the tumour microenvironment. This study provides an insight into the use of Resminostat as an epigenetic based therapeutic for HCC along with other pharmaceutical options, in particular by targeting the cell-to-cell communication that occurs between hepatoma and adipocytes.

Background Carcinogenesis is determined by various epigenetic events, such as histone deacetylation. The purpose of this study was to investigate the effect of the new histone deacetylase inhibitor resminostat on head and neck squamous cell carcinoma (HNSCC) cell lines. Methods The cytotoxicity of resminostat and cisplatin on HNSCC cell lines SCC25, CAL27, and FaDu was determined using CCK-8 cell proliferation assay and combination index analysis. Cells were irradiated with 2 to 8 Gray. Apoptosis was measured using flow cytometry and expression of Mcl-1, p-AKT, and survivin was investigated. Results Treatment with resminostat showed a decrease of cell proliferation of HNSCC cell lines. In addition, a synergistic effect with cisplatin as well as with radiation treatment could be observed. Induction of cell death and dose-dependent downregulation of survivin was evident in all cell lines. Conclusion Resminostat is a promising treatment of HNSCC because of its antiproliferative, chemosensitizing, and radiosensitizing effects. © 2017 Wiley Periodicals, Inc. Head Neck 39: 900–907, 2017

Objectives To determine the recommended dose and efficacy/safety of docetaxel combined with resminostat (DR) in non-small cell lung cancer (NSCLC) patients with previous platinum-based chemotherapy. Materials and Methods A multicenter, open-label, phase I/II study was performed in Japanese patients with stage IIIB/IV or recurrent NSCLC and prior platinum-based chemotherapy. The recommended phase II dose was determined using a standard 3 + 3 dose design in phase I part. Resminostat was escalated from 400 to 600 mg/day and docetaxel fixed at 75 mg/m2. In phase II part, the patients were randomly assigned to docetaxel alone (75 mg/m2) or DR therapy. Docetaxel was administered on day 1 and resminostat on days 1–5 in the DR group. Treatment was repeated every 21 days until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). Results A total of 117 patients (phase I part, 9; phase II part, 108) were enrolled. There was no dose-limiting toxicity in phase I part; the recommended dose for resminostat was 600 mg/day with 75 mg/m2 of docetaxel. In phase II part, median PFS (95% confidence interval [CI]) was 4.2 (2.8–5.7) months with docetaxel group and 4.1 (1.5–5.4) months with DR group (hazard ratio [HR]: 1.354, 95% CI: 0.835–2.195; p = 0.209). Grade ≥ 3 adverse events significantly more common with DR group than docetaxel group were leukopenia, febrile neutropenia, thrombocytopenia, and anorexia. Conclusion In Japanese NSCLC patients previously treated with platinum-based chemotherapy, DR therapy did not improve PFS compared with docetaxel alone and increased toxicity.

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, currently ranking as one of the highest neoplastic-related mortalities in the world. Due to the difficulty in early diagnosis and lack of effective treatment options, the 5-year survival rate of HCC remains extremely low. Histone deacetylation is one of the most important epigenetic mechanisms, regulating cellular events such as differentiation, proliferation and cell cycle. Histone deacetylases (HDACs), the chief mediators of this epigenetic mechanism, are often aberrantly expressed in various tumours including HCC. Areas covered: This review focuses on the most up-to-date findings of HDACs and their associated molecular mechanisms in HCC onset and progression. In addition, a potential network between HDACs and non-coding RNAs including microRNAs and long noncoding RNAs underlying hepatocarcinogenesis is considered. Expert opinion: Unmasking the role of HDACs and their association with HCC pathogenesis could have implications for future personalized therapeutic and diagnostic targeting.

The presence of T cell reservoirs in which human immunodeficiency virus (HIV) establishes latency by integrating into the host genome represents a major obstacle to an HIV cure and has prompted the development of strategies aimed at the eradication of HIV from latently infected cells. The “shock-and-kill” strategy is one of the most pursued approaches to the elimination of viral reservoirs. Although several latency-reversing agents (LRAs) have shown promising reactivation activity, they have failed to eliminate the cellular reservoir. In this study, we evaluated a novel immune system-mediated approach to clearing the HIV reservoir, based on a combination of innate immune stimulation and epigenetic reprogramming. The combination of the STING agonist cGAMP (cyclic GMP-AMP) and the FDA-approved histone deacetylase inhibitor resminostat resulted in a significant increase in HIV proviral reactivation and specific apoptosis in HIV-infected cells in vitro. Reductions in the proportion of HIV-harboring cells and the total amount of HIV DNA were also observed in CD4(+) central memory T (T(CM)) cells, a primary cell model of latency, where resminostat alone or together with cGAMP induced high levels of selective cell death. Finally, high levels of cell-associated HIV RNA were detected ex vivo in peripheral blood mononuclear cells (PBMCs) and CD4(+) T cells from individuals on suppressive antiretroviral therapy (ART). Although synergism was not detected in PBMCs with the combination, viral RNA expression was significantly increased in CD4(+) T cells. Collectively, these results represent a promising step toward HIV eradication by demonstrating the potential of innate immune activation and epigenetic modulation for reducing the viral reservoir and inducing specific death of HIV-infected cells. IMPORTANCE One of the challenges associated with HIV-1 infection is that despite antiretroviral therapies that reduce HIV-1 loads to undetectable levels, proviral DNA remains dormant in a subpopulation of T lymphocytes. Numerous strategies to clear residual virus by reactivating latent virus and eliminating the reservoir of HIV-1 (so-called “shock-and-kill” strategies) have been proposed. In the present study, we use a combination of small molecules that activate the cGAS-STING antiviral innate immune response (the di-cyclic nucleotide cGAMP) and epigenetic modulators (histone deacetylase inhibitors) that induce reactivation and HIV-infected T cell killing in cell lines, primary T lymphocytes, and patient samples. These studies represent a novel strategy for HIV eradication by reducing the viral reservoir and inducing specific death of HIV-infected cells.

Histone deacetylases (HDACs) hyper-activity in hepatocellular carcinoma (HCC) is often associated with patients' poor prognosis. Our previous study has shown that resminostat, a novel HDAC inhibitor (HDACi), activated mitochondrial permeability transition pore (mPTP)-dependent apoptosis pathway in HCC cells. Here we explored the potential resminostat resistance factor by focusing on mammalian target of rapamycin (mTOR). We showed that AZD-2014, a novel mTOR kinase inhibitor, potentiated resminostat-induced cytotoxicity and proliferation inhibition in HCC cells. Molecularly, AZD-2014 enhanced resminostat-induced mPTP apoptosis pathway activation in HCC cells. Inhibition of this apoptosis pathway, by the caspase-9 specific inhibitor Ac-LEHD-CHO, the mPTP blockers (sanglifehrin A/cyclosporine A), or by shRNA-mediated knockdown of mPTP component cyclophilin-D (Cyp-D), significantly attenuated resminostat plus AZD-2014-induced cytotoxicity and apoptosis in HCC cells. Significantly, mTOR shRNA knockdown or kinase-dead mutation (Asp-2338-Ala) also sensitized HCC cells to resminostat, causing profound cytotoxicity and apoptosis induction. Together, these results suggest that mTOR could be a primary resistance factor of resminostat. Targeted inhibition of mTOR may thus significantly sensitize HCC cells to resminostat.

This open-label, single-arm phase II study examined efficacy, safety, pharmacokinetics, and biomarkers of histone deacetylase (HDAC) inhibitor resminostat in patients with relapsed or refractory Hodgkin lymphoma. Thirty-seven heavily pretreated patients received 600 (19 patients) or 800 mg (18 patients) oral resminostat daily for the initial 5 days of 14-day treatment cycles. Objective response rate (ORR) (primary) was 34% reaching disease control in 54% patients. Most patients (69%) showed reduced tumor size and reduced [

Hepatocellular carcinoma (HCC) is a major contributor to the global cancer burden. Given the current limited options to treat advanced HCC, understanding the molecular basis of HCC carcinogenesis and pinpointing druggable targets will be important to identify future HCC treatments. Epigenetic modification by inhibiting histone deacetylases (HDAC) is an emerging approach with promising results in cancer treatment. In the preclinical setting, HDAC inhibitors such as valproic acid sodium, panobinostat, vorinostat, trichostatin A, sodium butyrate, belinostat and romidepsin have demonstrated antitumor efficacy via activation of classic and alternative cell death molecular cascades. Combination regimens with the tyrosine kinase inhibitor sorafenib, poly(ADP-ribose) polymerases, proteasome and mammalian target of rapamycin inhibitors have shown promise. Phase I/II clinical studies with belinostat monotherapy and the combination of resminostat with sorafenib have suggested response and survival benefits. The safety profile was favorable with manageable adverse events and a low incidence of grade 3/4 toxicity. We herein review the role and potential therapeutic impact of epigenetic regulation through histone deacetylase inhibitors (HDACi) in the treatment of HCC.

This study was performed to evaluate the safety and determine the recommended dose (RD) of resminostat monotherapy, an oral histone deacetylase (HDAC) inhibitor, in Japanese patients with advanced solid tumors. Resminostat was administered to patients with advanced solid tumors on a 14-day cycle consisting of once-daily administration on days 1–5. The dose was initiated at 400 mg and increased to 600 mg and then 800 mg. Treatment with resminostat was continued until disease progression or discontinuation for any other reason. Dose-limiting toxicities (DLTs) were assessed according to the adverse drug reactions occurring in the first cycle. Secondary objectives included the pharmacokinetics, pharmacodynamics, and efficacy. A total of 12 patients were enrolled in the study and received resminostat. No DLTs were reported in any patient. The maximum tolerated dose was not reached. Frequently reported grade 3/4 adverse drug reactions were as follows: lymphocytopenia (33.3 %), thrombocytopenia (25.0 %), neutropenia (16.7 %), and leukocytopenia (16.7 %). Pharmacokinetic analysis revealed that there was no accumulation of the drug over the 5-day administration period and no significant difference in pharmacokinetic parameters between the single dose and multiple doses. Measurement of acetylated H4 histone protein levels in peripheral blood mononuclear cells demonstrated that resminostat inhibited HDAC activity at all the doses assessed. No patients had a complete or partial response, whereas three patients had stable disease. Resminostat was safely administered to Japanese patients with advanced solid tumors. The RD of resminostat monotherapy in Japanese patients was estimated to be 800 mg.

// Jitka Soukupova 1 , Esther Bertran 1 , Irene Penuelas-Haro 1 , Uxue Urdiroz-Urricelqui 1, 2 , Matthias Borgman 3 , Hella Kohlhof 3, 4 and Isabel Fabregat 1, 2 1 “TGF-β and cancer” group, Oncobell Program. Bellvitge Biomedical Research Institute, (IDIBELL), L´Hospitalet, Barcelona, Spain 2 Department of Physiological Sciences, Faculty of Medicine and Health Sciences. University of Barcelona (UB), L´Hospitalet, Barcelona, Spain 3 4SC AG, Planegg-Martinsried, Germany 4 Immunic AG, Planegg-Martinsried, Germany Correspondence to: Isabel Fabregat, email: ifabregat@idibell.cat Keywords: HDAC inhibitors; HCC; EMT; resminostat; sorafenib Received: March 29, 2017 Accepted: November 17, 2017 Published: November 30, 2017 ABSTRACT Resminostat, a novel class I, IIb, and IV histone deacetylase inhibitor, was studied in advanced hepatocellular carcinoma (HCC) patients after relapse to sorafenib (SHELTER study). In this phase I/II clinical trial, combination of sorafenib and resminostat was safe and showed early signs of efficacy. However, the molecular mechanisms behind this synergism have not been explored yet. In this work, we aimed to analyze whether resminostat regulates epithelial-mesenchymal and stemness phenotype as a mechanism of sensitization to sorafenib. Three HCC cell lines with differences in their epithelial/mesenchymal characteristics were treated with resminostat and sorafenib alone, or in combination. Resminostat prevented growth and induced cell death in the HCC cells, in a time and dose dependent manner. A collaborative effect between resminostat and sorafenib was detected in the mesenchymal HCC cells, which were insensitive to sorafenib-induced apoptosis. Expression of mesenchymal-related genes was decreased in resminostat-treated HCC cells, concomitant with an increase in epithelial-related gene expression, organized tight junctions and reduced invasive growth. Moreover, resminostat down-regulated CD44 expression, coincident with decreased capacity to form colonies at low cell density. Conclusion: Resminostat shifts mesenchymal cells towards a more epithelial phenotype, lower invasive and stemness properties, which may contribute to the sensitization to sorafenib-induced apoptosis.

Introduction In a recent phase I/II clinical trial in hepatocellular carcinoma (HCC), (NCT02400788), the combination of HDAC-inhibitor resminostat (YHI1001) with a multi-kinase inhibitor sorafenib was clinically beneficial compared to sorafenib mono-treatment in patients with platelet counts ≥1.5 × 10 5 /µl, but not below that threshold. In HCC, platelets have been linked to bad prognosis, tumour growth and metastasis as well as to resistance against the standard treatment with sorafenib. This begs the question how platelets affect HCC cells and modulate their drug response. Material and methods Several HCC cell lines were used to compare phenotypical features, susceptibility to platelets and drug-mediated effects. To determine effects on cancer cell features, in vitro cell growth and transwell invasion assays were performed. Furthermore, the underlying mechanism of a platelet-modulated drug response on the molecular level was explored. Results and discussions In HCC cells, the anti-proliferative potency of sorafenib was counteracted by platelet factors and the mesenchymal phenotype. However, resminostat alone and in combination with sorafenib effectively triggered an anti-proliferative response independently of platelets or the mesenchymal phenotype. Therefore, resminostat determined the anti-proliferative response of the drug combination. Moreover, recent reports highlight HCC cell subpopulations which express cancer stem cell genes and harbour clonogenic growth and cell invasive capacities as critical for metastasis. Intriguingly, we found that platelets induced the cell-invasive capacity in HCC cells with detectable levels of several cancer stem cell markers and which featured a mixed epithelial-mesenchymal phenotype. Importantly, only the combination of resminostat with sorafenib, but not the mono-treatments, significantly reversed the platelet-induced cell invasion. Conclusion Our pre-clinical data provide evidence on how platelets mediate pro-tumorigenic effects and modulate the therapeutic response to the resminostat/sorafenib drug combination. Platelet factors negatively modulated the drug response to sorafenib. This was overcome by the anti-proliferative activities of resminostat. Importantly, providing an explanation for the clinical benefit of the combination therapy, the platelet-induced invasive capacity was reversed only by the combination of resminostat with sorafenib, but not the mono-treatments.

Introduction Cutaneous T cell lymphoma (CTCL) is a heterogeneous group of extra-nodal non-Hodgkin lymphomas arising from transformation and clonal expansion of skin-homing T cells. Epigenetics alterations have been described for the molecular pathogenesis of CTCL. Resminostat is a potent, orally bioavailable histone deacetylase (HDAC) inhibitor targeting class I, IIb and IV and is currently in phase II of clinical development. Resminostat showed anti-tumoral in vitro efficacy by inhibiting proliferation of CTCL cell lines. The aim of this study was to elucidate resminostat’s molecular mechanism of action in CTCL using a genome-wide approach. Material and methods Resminostat’s mechanism of action was analysed using a set of established CTCL cell lines representing different types of CTCL. Global lysine acetylation was evaluated by flow cytometry and specific histone H3 acetylation at lysine residue 27 (H3K27ac) was mapped genome-widely by chromatin immunoprecipitation followed by sequencing (ChIP-seq). Resminostat’s effect on global gene expression was analysed by RNA-seq focusing on CTCL-relevant pathways and genes. Results and discussions Resminostat increased total lysine acetylation in CTCL cell lines. The active epigenetic mark H3K27ac dose-dependently accumulated on a genome-wide level as detected by ChIP-seq analysis. Global gene expression profiling revealed both gene induction and repression by resminostat. First data showed a regulation of T helper (Th) 1 and 2 specific genes implying that resminostat normalises the Th1/Th2 imbalance in CTCL which is discussed to be associated with disease progression. Moreover, expression of skin-homing receptor genes was reduced by resminostat indicating a potential effect of resminostat on the cutaneous tropism of malignant T cells. Furthermore, the pruritus mediator IL-31 was downregulated by resminostat suggesting an attenuation of itching and thus indicating an important benefit for CTCL patients regarding their health-related quality of life. Conclusion First results from a genome-wide study suggest a promising impact of resminostat on different targets relevant for the pathogenesis of CTCL. These data broaden our understanding of resminostat’s molecular mechanism of action in CTCL and support our current clinical phase II trial evaluating resminostat for maintenance treatment of patients with advanced stage CTCL (RESMAIN, NCT02953301).

Histone deacetylase inhibitors (HDACi) have been actively explored as anti-cancer agents due to their ability to prevent deacetylation of histones, resulting in uncoiling of chromatin and stimulation of a range of genes associated in the regulation of cell survival, proliferation, differentiation and apoptosis. During the past several years, many HDACi have entered pre-clinical or clinical research as anti-cancer agents with satisfying results. Out of these, more than 8 novel hydroxamic acid based HDACi i.e., belinostat, abexinostat, SB939, resminostat, givinostat, quisinostat, pentobinostat, CUDC-101 are in clinical trials and one of the drug vorinostat (SAHA) has been approved by US FDA for cutaneous T-cell lymphoma (CTCL). It is clear from the plethora of new molecules and the encouraging results from clinical trials that this class of HDAC inhibitors hold a great deal of promise for the treatment of a variety of cancers. In this review, we classified the hydroxamic acid based HDACi on the basis of their structural features into saturated, unsaturated, branched, un-branched and 5, 6-membered cyclic ring linker present between zinc binding group and connecting unit. The present article enlists reports on hydroxamic acid based HDACi designed and developed using concepts of medicinal chemistry, demonstrating that hydroxamate derivatives represent a versatile class of compounds leading to novel imaging and therapeutic agents. This article will also provide a complete insight into various structural modifications required for optimum anticancer activity.

AT-04. TOWARDS AN EPIGENETIC THERAPY FOR RHABDOID TUMORS -IN VITRO RESULTS FOR THE EPIGENETIC MODULATORS RESMINOSTAT AND 4SC-202 Hella Kohlhof2, Tanja Wulff2, Daniel Vitt2, and Michael Fruehwald1; Children’s Hospital Augsburg, Augsburg, Germany; 4SC AG, Martinsried, Germany Among others histone deactyleases 1 and 2 (HDAC1, 2) are overexpressed across all molecular subgroups of AT/RT. Resminostat is an orally available inhibitor of HDAC classes I and IIb; whereas 4SC-202 is a combined inhibitor of HDAC1/2/3 and the lysine specific demethylase LSD1. Additionally, 4SC-202 inhibits the SMO-independent HH signaling which is often aberrantly activated in AT/RT. Both inhibitors have proven tolerability and efficacy in phase I or II trials in adults. Their toxicity profile appears to be favorable while maintaining targeting efficacy. Proliferation and viability of cell lines G401 (RTK), A204 (MRT) and CHLA-02 (AT/ RT) were evaluated by crystal violet staining and MTT, spheroid and colony formation assays. Expression of genes associated with the phenotype of rhabdoid tumors such as SMARCB1, CDKN1C, MYC, CyclinD1 and HHIP was examined by qRT-PCR. As comparative HDACi Vorinostat, Panobinostat, Entinostat, Mocetinostat and Ricolinostat were tested. Resminostat and 4SC-202 exhibited a dose dependent inhibition of proliferation and viability of RT cells. Inhibition of the capacity for clonogenic growth was demonstrated. Gene expression data are currently evaluated. Rhabdoid tumors as paradigmatic epigenetic malignancies appear to be the optimal foci for drugs targeting the epigenetic scaffolding of tumor cells. The epigenetic modulators Resminostat and 4SC-202 warrant further testing in clinical trials in children with rhabdoid tumors. Likely combinatorial therapy will be needed to prove a significant effect on outcome for affected high-risk patients. Neuro-Oncology 18:iii1–iii6, 2016. doi:10.1093/neuonc/now065.3 #The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Over-expression and aberrant activation of histone deacetylases (HDACs) are often associated with poor prognosis of hepatocellular carcinoma (HCC). Here, we evaluated the potential anti-hepatocellular carcinoma (HCC) cell activity by resminostat, a novel pan HDAC inhibitor (HDACi). We demonstrated that resminostat induced potent cytotoxic and anti-proliferative activity against established HCC cell lines (HepG2, HepB3, SMMC-7721) and patient-derived primary HCC cells. Further, resminostat treatment in HCC cells activated mitochondrial permeability transition pore (mPTP)-dependent apoptosis pathway, which was evidenced by physical association of cyclophilin-D and adenine nucleotide translocator 1 (ANT-1), mitochondrial depolarization, cytochrome C release and caspase-9 activation. Intriguingly, the mPTP blockers (sanglifehrin A and cyclosporine A), shRNA knockdown of cyclophilin-D or the caspase-9 inhibitor dramatically attenuated resminostat-induced HCC cell apoptosis and cytotoxicity. Reversely, HCC cells with exogenous cyclophilin-D over-expression were hyper-sensitive to resminostat. Intriguingly, a low concentration of resminostat remarkably potentiated sorafenib-induced mitochondrial apoptosis pathway activation, leading to a profound cytotoxicity in HCC cells. The results of this preclinical study indicate that resminostat (or plus sorafenib) could be further investigated as a valuable anti-HCC strategy.

Background & Aims No established therapies for patients with hepatocellular carcinoma (HCC) and progression on first-line sorafenib treatment currently exist. This phase I/II trial investigated safety, pharmacokinetics and potential biomarkers of the histone deacetylase inhibitor resminostat and a combination therapy with resminostat and sorafenib. Methods Patients with HCC and radiologically confirmed progression on sorafenib were treated in an exploratory, multi-center, open-label, uncontrolled, non-randomized, parallel group phase I/II study. In the combination group (n=38) four dose levels ranged from daily 200 to 600mg resminostat plus 400 to 800mg sorafenib. The monotherapy group (n=19) received 600mg resminostat. Results 57 patients received treatment. Most common adverse events were gastrointestinal disorders, thrombocytopenia and fatigue. Median maximal histone deacetylase inhibition and highest increase in H4-acetylation matched T max of resminostat. Sorafenib or the Child-Pugh score did not affect typical pharmacokinetics characteristics of resminostat. Efficacy assessment as progression-free survival-rate after 6 treatment cycles (12weeks, primary endpoint) was 12.5% for resminostat and 62.5% for resminostat plus sorafenib. Median time to progression and overall survival were 1.8 and 4.1months for resminostat and 6.5 and 8.0months for the combination, respectively. Zinc finger protein 64 (ZFP64) baseline expression in blood cells was found to correlate with overall survival. Conclusions The combination of sorafenib and resminostat in HCC patients was safe and showed early signs of efficacy. Sorafenib did not alter the pharmacokinetic profile of resminostat or its histone deacetylase inhibitory activity in vivo . A prognostic and potentially predictive role of ZFP64 for treatment with resminostat should be further investigated in HCC and possibly other cancer indications. Lay summary No established therapy for patients with advanced hepatocellular carcinoma and progression under first-line systemic treatment with sorafenib currently exists. Epigenetic modulation by inhibition of histone deacetylases might be able to overcome therapy resistance. This exploratory phase I/II clinical study in patients with radiologically confirmed progression under first-line treatment with sorafenib investigated the histone deacetylases inhibitor resminostat as single agent or in combination with continued application of sorafenib. Clinical trial registration The clinical trial has been registered at www.clinicaltrials.gov as NCT00943449.

e14571Background: A phase I/II clinical trial in advanced hepatocellular carcinoma (HCC) conducted by Yakult Honsha (NCT02400788) indicated the combination of the HDAC inhibitor resminostat and sor...

Summary Inhibition of histone deacetylase (HDAC) is a promising mechanism for novel, anti-myeloma agents. We investigated the effects of the novel HDAC inhibitor resminostat on multiple myeloma (MM) cells in vitro. Resminostat is a potent inhibitor of HDACs 1, 3 and 6 [50% inhibitory concentration (IC50) = 43–72 nmol/l] representing HDAC classes I and II and induces hyperacetylation of histone H4 in MM cells. Low micromolar concentrations of resminostat abrogated cell growth and strongly induced apoptosis (IC50 = 2·5–3 μmol/l in 3 out of 4 MM cell lines) in MM cell lines as well as primary MM cells. At 1 μmol/l, resminostat inhibited proliferation and induced G0/G1 cell cycle arrest in 3 out of 4 MM cell lines accompanied with decreased levels of cyclin D1, cdc25a, Cdk4 and pRb as well as upregulation of p21. Resminostat decreased phosphorylation of 4E-BP1 and p70S6k indicating an interference with Akt pathway signalling. Treatment with resminostat resulted in increased protein levels of Bim and Bax and decreased levels of Bcl-xL. Caspases 3, 8 and 9 were activated by resminostat. Furthermore, synergistic effects were observed for combinations of resminostat with melphalan and the proteasome inhibitors bortezomib and S-2209. In conclusion, we have identified potent anti-myeloma activity for this novel HDAC inhibitor.