Ezurpimtrostat, A Palmitoyl-Protein Thioesterase-1 Inhibitor, Combined with PD-1 Inhibition Provides CD8+ Lymphocyte Repopulation in Hepatocellular Carcinoma.

BACKGROUND: Palmitoyl-protein thioesterase-1 (PPT1) is a clinical stage druggable target for inhibiting autophagy in cancer. OBJECTIVE: We aimed to determine the cellular and molecular activity of targeting PPT1 using ezurpimtrostat, in combination with an anti-PD-1 antibody. METHODS: In this study we used a transgenic immunocompetent mouse model of hepatocellular carcinoma. RESULTS: Herein, we revealed that inhibition of PPT1 using ezurpimtrostat decreased the liver tumor burden in a mouse model of hepatocellular carcinoma by inducing the penetration of lymphocytes into tumors when combined with anti-programmed death-1 (PD-1). Inhibition of PPT1 potentiates the effects of anti-PD-1 immunotherapy by increasing the expression of major histocompatibility complex (MHC)-I at the surface of liver cancer cells and modulates immunity through recolonization and activation of cytotoxic CD8+ lymphocytes. CONCLUSIONS: Ezurpimtrostat turns cold tumors into hot tumors and, thus, could improve T cell-mediated immunotherapies in liver cancer.

First-In-Human Effects of PPT1 Inhibition Using the Oral Treatment with GNS561/Ezurpimtrostat in Patients with Primary and Secondary Liver Cancers.

Introduction: GNS561/Ezurpimtrostat is a first-in-class, orally bioavailable, small molecule that blocks cancer cell proliferation by inhibiting late-stage autophagy and dose-dependent build-up of enlarged lysosomes by interacting with the palmitoyl-protein thioesterase 1 (PPT1). Methods: This phase I, open-label, dose-escalation trial (3 + 3 design) explored two GNS561 dosing schedules: one single oral intake 3 times a week (Q3W) and twice daily (BID) continuous oral administration in patients with advanced hepatocellular carcinoma, cholangiocarcinoma, and pancreatic adenocarcinoma or colorectal adenocarcinomas with liver metastasis. The primary objective was to determine GNS561 recommended phase II dose (RP2D) and schedule. Secondary objectives included evaluation of the safety/tolerability, pharmacokinetics, pharmacodynamics, and antitumor activity of GNS561. Results: Dose escalation ranged from 50 to 400 mg Q3W to 200-300 mg BID. Among 26 evaluable patients for safety, 20 were evaluable for efficacy and no dose-limiting toxicity was observed. Adverse events (AEs) included gastrointestinal grade 1-2 events, primarily nausea and vomiting occurred in 13 (50%) and 14 (54%) patients, respectively, and diarrhea in 11 (42%) patients. Seven grade 3 AEs were reported (diarrhea, decreased appetite, fatigue, alanine aminotransferase, and aspartate aminotransferase increased). Q3W administration was associated with limited exposure and the BID schedule was preferred. At 200 mg BID GNS561, plasma and liver concentrations were comparable to active doses in animal models. Liver trough concentrations were much higher than in plasma a median time of 28 days of administration with a mean liver to plasma ratio of 9,559 (Min 149-Max 25,759), which is in accordance with rat preclinical data observed after repeated administration. PPT1 expression in cancer tissues in the liver was reduced upon GNS561 exposure. There was no complete or partial response. Five patients experienced tumor stable diseases (25%), including one minor response (-23%). Conclusion: Based on a favorable safety profile, exposure, and preliminary signal of activity, oral GNS561 RP2D was set at 200 mg BID. Studies to evaluate the antitumor activity of GNS561 in hepatocarcinoma cells and intrahepatic cholangiocarcinoma are to follow NCT03316222.

GNS561, a clinical-stage PPT1 inhibitor, is efficient against hepatocellular carcinoma via modulation of lysosomal functions.

Hepatocellular carcinoma is the most frequent primary liver cancer. Macroautophagy/autophagy inhibitors have been extensively studied in cancer but, to date, none has reached efficacy in clinical trials. In this study, we demonstrated that GNS561, a new autophagy inhibitor, whose anticancer activity was previously linked to lysosomal cell death, displayed high liver tropism and potent antitumor activity against a panel of human cancer cell lines and in two hepatocellular carcinoma in vivo models. We showed that due to its lysosomotropic properties, GNS561 could reach and specifically inhibited its enzyme target, PPT1 (palmitoyl-protein thioesterase 1), resulting in lysosomal unbound Zn2+ accumulation, impairment of cathepsin activity, blockage of autophagic flux, altered location of MTOR (mechanistic target of rapamycin kinase), lysosomal membrane permeabilization, caspase activation and cell death. Accordingly, GNS561, for which a global phase 1b clinical trial in liver cancers was just successfully achieved, represents a promising new drug candidate and a hopeful therapeutic strategy in cancer treatment.Abbreviations: ANXA5:annexin A5; ATCC: American type culture collection; BafA1: bafilomycin A1; BSA: bovine serum albumin; CASP3: caspase 3; CASP7: caspase 7; CASP8: caspase 8; CCND1: cyclin D1; CTSB: cathepsin B; CTSD: cathepsin D; CTSL: cathepsin L; CQ: chloroquine; iCCA: intrahepatic cholangiocarcinoma; DEN: diethylnitrosamine; DMEM: Dulbelcco's modified Eagle medium; FBS: fetal bovine serum; FITC: fluorescein isothiocyanate; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HCC: hepatocellular carcinoma; HCQ: hydroxychloroquine; HDSF: hexadecylsulfonylfluoride; IC50: mean half-maximal inhibitory concentration; LAMP: lysosomal associated membrane protein; LC3-II: phosphatidylethanolamine-conjugated form of MAP1LC3; LMP: lysosomal membrane permeabilization; MALDI: matrix assisted laser desorption ionization; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MKI67: marker of proliferation Ki-67; MTOR: mechanistic target of rapamycin kinase; MRI: magnetic resonance imaging; NH4Cl: ammonium chloride; NtBuHA: N-tert-butylhydroxylamine; PARP: poly(ADP-ribose) polymerase; PBS: phosphate-buffered saline; PPT1: palmitoyl-protein thioesterase 1; SD: standard deviation; SEM: standard error mean; vs, versus; Zn2+: zinc ion; Z-Phe: Z-Phe-Tyt(tBu)-diazomethylketone; Z-VAD-FMK: carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]- fluoromethylketone.

Prospective screening of liver fibrosis in a primary care cohort using systematic calculation of fib-4 in routine results.

BACKGROUND & AIM: Liver fibrosis screening in primary care population is a major public health issue. The FIB-4 index is a simple non-invasive fibrosis test combining age, transaminases, platelets count, developed for the diagnosis of advanced fibrosis. The aim of our study was to evaluate the interest of liver fibrosis screening using systematic calculation of FIB-4 in routine blood analysis. METHODS: Between December 2018 and May 2019, we conducted a prospective screening of liver fibrosis in 134 158 patients during a medical check-up including routine blood analysis. Among these patients, 29 707 had transaminases and platelets counts available and benefited from an automatic calculation of FIB-4. Results were obtained from 21 French clinical laboratories in the Bouches du Rhône region. RESULTS: Among the 29 707 patients, 2161 (7.3%) had a high risk of advanced fibrosis (FIB-4>2.67). Individual investigation of patients with FIB-4>2.67 allowed to screen 1268 (1268/2161: 58.7%) patients who were not managed for any liver disease. CONCLUSIONS: This work demonstrates the interest of FIB-4 for the screening of liver fibrosis in primary care population. Although additional clinical validation study is required to determine the utility and applicability of Fib-4 to daily practice, our study strongly supports this easy-to-implement strategy using a simple Fib-4 measure resulting from the use of available routine test results.

GNS561 acts as a potent anti-fibrotic and pro-fibrolytic agent in liver fibrosis through TGF-ß1 inhibition.

BACKGROUND: Hepatic fibrosis is the result of chronic liver injury that can progress to cirrhosis and lead to liver failure. Nevertheless, there are no anti-fibrotic drugs licensed for human use. Here, we investigated the anti-fibrotic activity of GNS561, a new lysosomotropic molecule with high liver tropism. METHODS: The anti-fibrotic effect of GNS561 was determined in vitro using LX-2 hepatic stellate cells (HSCs) and primary human HSCs by studying cell viability, activity of caspases 3/7, autophagic flux, cathepsin maturation and activity, HSC activation and transforming growth factor-ß1 (TGF-ß1) maturation and signaling. The contribution of GNS561 lysosomotropism to its anti-fibrotic activity was assessed by increasing lysosomal pH. The potency of GNS561 on fibrosis was evaluated in vivo in a rat model of diethylnitrosamine-induced liver fibrosis. RESULTS: GNS561 significantly decreased cell viability and promoted apoptosis. Disrupting the lysosomal pH gradient impaired its pharmacological effects, suggesting that GNS561 lysosomotropism mediated cell death. GNS561 impaired cathepsin activity, leading to defective TGF-ß1 maturation and autophagic processes. Moreover, GNS561 decreased HSC activation and extracellular matrix deposition by downregulating TGF-ß1/Smad and mitogen-activated proteine kinase signaling and inducing fibrolysis. Finally, oral administration of GNS561 (15 mg/kg per day) was well tolerated and attenuated diethylnitrosamine-induced liver fibrosis in this rat model (decrease of collagen deposition and of pro-fibrotic markers and increase of fibrolysis). CONCLUSION: GNS561 is a new potent lysosomotropic compound that could represent a valid medicinal option for hepatic fibrosis treatment through both its anti-fibrotic and its pro-fibrolytic effects. In addition, this study provides a rationale for targeting lysosomes as a promising therapeutic strategy in liver fibrosis.

GNS561, a new lysosomotropic small molecule, for the treatment of intrahepatic cholangiocarcinoma.

Among the acquired modifications in cancer cells, changes in lysosomal phenotype and functions are well described, making lysosomes a potential target for novel therapies. Some weak base lipophilic drugs have a particular affinity towards lysosomes, taking benefits from lysosomal trapping to exert anticancer activity. Here, we have developed a new lysosomotropic small molecule, GNS561, and assessed its activity in multiple in vitro intrahepatic cholangiocarcinoma models (HuCCT1 and RBE cell lines and patient-derived cells) and in a chicken chorioallantoic membrane xenograft model. GNS561 significantly reduced cell viability in two intrahepatic cholangiocarcinoma cell lines (IC50 of 1.5 ± 0.2 µM in HuCCT1 and IC50 of 1.7 ± 0.1 µM in RBE cells) and induced apoptosis as measured by caspases activation. We confirmed that GNS561-mediated cell death was related to its lysosomotropic properties. GNS561 induced lysosomal dysregulation as proven by inhibition of late-stage autophagy and induction of a dose-dependent build-up of enlarged lysosomes. In patient-derived cells, GNS561 was more potent than cisplatin and gemcitabine in 2/5 and 1/5 of the patient-derived cells models, respectively. Moreover, in these models, GNS561 was potent in models with low sensitivity to gemcitabine. GNS561 was also efficient in vivo against a human intrahepatic cholangiocarcinoma cell line in a chicken chorioallantoic membrane xenograft model, with a good tolerance at doses high enough to induce an antitumor effect in this model. In summary, GNS561 is a new lysosomotropic agent, with an anticancer activity against intrahepatic cholangiocarcinoma. Further investigations are currently ongoing to fully elucidate its mechanism of action.

Sofosbuvir plus ledipasvir in combination for the treatment of hepatitis C infection.

Sofsobuvir is the first-in-class NS5B nucleotide inhibitor to be launched as a treatment for the hepatitis C virus (HCV). Its viral potency, pan genotypic activity and high barrier to resistance make it the ideal candidate to become a backbone for several IFN-free regimens. Ledipasvir is a NS5A inhibitor with multi genotypic activity but modest barrier to resistance. The once-daily fixed-dose combination of sofosbuvir plus ledipasvir is the first-in-market single-tablet regimen for the treatment of hepatitis C infection. Recent data demonstrated that this FDC alone, or in combination with ribavirin, is able to achieve HCV cure of at least 90% or more among genotype 1,4, 5 and 6 patients. This combination appears to be suboptimal in genotype 3 patients and other direct acting antiviral combinations with sofosbuvir will help to fulfill this gap in the near future. The safety profile of the fixed dose combination is good. Resistance is not an issue with sofosbuvir but may be a significant issue with regards to ledipasvir for those rare individuals who harbor baseline HCV NS5A resistance-associated variants that conferred a high resistance level. The rational for using FDCs and the available clinical data are reviewed.

Optimal therapy of genotype-2 chronic hepatitis C: what's new?

The standard of care (SOC) for the treatment of HCV genotype 2 (HCV-2) was pegylated interferon alpha plus ribavirin (PEG-IFN/RBV) at weight-based doses for a response-guided duration. The launches of sofosbuvir and daclatasvir in 2014 have resulted in new, better tolerated and shorter treatment. The combination of sofosbuvir and RBV for 12 weeks appears to be the new SOC in both European and American guidelines. The cost and therefore the access to this treatment remains a problem in many countries because of major economic constraints. For the few more difficult-to-treat patients, a combination of direct acting antivirals may be suitable and is being studied in ongoing trials. Because of rapidly changing treatment recommendations, the decision to treat HCV-2 patients with currently approved drugs or to wait until a better option is available in the future, must be made according to the stage of fibrosis.

Sofosbuvir as backbone of interferon free treatments.

Sofosbuvir is the first-in-class NS5B nucleotide analogues to be launched for hepatitis C virus (HCV) treatment. Its viral potency, pangenotypic activity and high barrier to resistance make it the ideal candidate to become a backbone for several IFN-free regimens. Recent data demonstrated that sofosbuvir either with ribavirin alone or in combination with other direct-acting antivirals (DAAs) as daclatasvir, ledipasvir or simeprevir are able to cure HCV in at least 90% or over of patients. Treatment experienced genotype 3 population may remain the most difficult to treat population, but ongoing DAA combination studies will help to fill this gap. Safety profile of sofosbuvir or combination with other DAAs is good. Resistance to sofosbuvir did not appear as a significant issue. The rationale for using this class of drug and the available clinical data are reviewed.

Chronic hepatitis C: future treatment.

The launch of first-generation protease inhibitors (PIs) is a major step forward in HCV treatment. However, the major advance is up to now restricted to genotype 1 (GT-1) patients. The development of second-wave and second-generation PIs yields higher antiviral potency through plurigenotypic activity, more convenient daily administration, fewer side effects and, for the second-generation PIs, potential activity against resistance-associated variants. NS5B inhibitors include nucleoside/nucleotide inhibitors (NIs) and non-nucleotide inhibitors (NNIs). NIs have high efficacy across all genotypes. Sofosbuvir has highly potent antiviral activity across all genotypes in association with pegylated interferon and ribavirin (PR), thus allowing shortened treatment duration. NS5A inhibitors (NS5A.I) have highly potent antiviral activity. It has recently been shown for the first time that NS5A.I in combination with protease inhibitors can cure GT-1b null responders in an interferon-free regimen. Besides, several studies demonstrate that interferon (IFN)-free regimens with direct-acting antiviral agent combinations are able to cure a large number of either naïve or treatment-experienced GT-1 patients. Moreover, quadruple regimen with PR is able to cure almost all GT-1 null responders. The development of pan-genotypic direct-acting antiviral agents (NIs or NS5A.I) allows new combinations with or without PR that increase the rate of sustained virological response for all patients, even for those with cirrhosis and independently of the genotype. Therefore, the near future of HCV treatment looks promising. The purpose of this article is to provide an overview of the clinical results recently reported for HCV treatment.

How to optimize current therapy of HCV genotype 1 infection with boceprevir.

Treatment with first generation protease inhibitors (PIs) is a milestone in the history of HCV therapy. Triple therapy with boceprevir (BOC) improves sustained virological response (SVR) by 30% in treatment naïve genotype 1 patients and by 50-60% in relapsers, 40-45% in partial responders and 25% in null responders compared with the Pegylated Interferon (PEG-IFN) and ribavirin regimen. To optimize BOC treatment, screening and access to treatment must be improved in genotype 1 patients. To select the ideal candidate for immediate treatment with triple therapy, an individual risk/benefit ratio must be assessed. Recent data have shown that patients with compensated cirrhosis and more advanced disease may also benefit from this regimen. Moreover, in HCV patients with extrahepatic manifestations, patients with HCV recurrence after liver transplantation and HIV-HCV co-infected patients, immediate treatment with triple therapy should be discussed. There is growing evidence that triple therapy with BOC is cost-effective in genotype 1 patients. Finally, the treatment design of BOC must be optimized in relation to baseline characteristics, so that optimal stopping rules can be followed, Drug-drug interactions (DDIs) can be prevented and AEs can be accurately prevented and managed.

[Treatment of hepatitis C]. / Traitement de l'hépatite C.

Hepatitis C treatment has made a lot of progress in the last two decades. Treatment with pegylated interferon and ribarin is associated with sustained virological response in more than 50% of patients. This improvement is due in one part to the adaptation of treatment dose and duration according to genotype, liver fibrosis and response-guided therapy, fibrosis in another part to a better pretreatment management of co-morbidities and a better prevention and management of side effects. New direct antiviral agents will become soon available and will lead to an improvement of sustained virological response with maybe more complex therapy leading to a new management of patients.