GS-0976 (Firsocostat): an investigational liver-directed acetyl-CoA carboxylase (ACC) inhibitor for the treatment of non-alcoholic steatohepatitis (NASH)

Metabolism of immune cells in cancer

Through the successes of checkpoint blockade and adoptive cellular therapy, immunotherapy has become an established treatment modality for cancer. Cellular metabolism has emerged as a critical determinant of the viability and function of both cancer cells and immune cells. In order to sustain prodigious anabolic needs, tumours employ a specialized metabolism that differs from untransformed somatic cells. This metabolism leads to a tumour microenvironment that is commonly acidic, hypoxic and/or depleted of critical nutrients required by immune cells. In this context, tumour metabolism itself is a checkpoint that can limit immune-mediated tumour destruction. Because our understanding of immune cell metabolism and cancer metabolism has grown significantly in the past decade, we are on the cusp of being able to unravel the interaction of cancer cell metabolism and immune metabolism in therapeutically meaningful ways. Although there are metabolic processes that are seemingly fundamental to both cancer and responding immune cells, metabolic heterogeneity and plasticity may serve to distinguish the two. As such, understanding the differential metabolic requirements of the diverse cells that comprise an immune response to cancer offers an opportunity to selectively regulate immune cell function. Such a nuanced evaluation of cancer and immune metabolism can uncover metabolic vulnerabilities and therapeutic windows upon which to intervene for enhanced immunotherapy.

From overnutrition to liver injury: AMP-activated protein kinase in nonalcoholic fatty liver diseases

Nonalcoholic fatty liver diseases (NAFLDs), especially nonalcoholic steatohepatitis (NASH), have become a major cause of liver transplant and liver-associated death. However, the pathogenesis of NASH is still unclear. Currently, there is no FDA-approved medication to treat this devastating disease. AMP-activated protein kinase (AMPK) senses energy status and regulates metabolic processes to maintain homeostasis. The activity of AMPK is regulated by the availability of nutrients, such as carbohydrates, lipids, and amino acids. AMPK activity is increased by nutrient deprivation and inhibited by overnutrition, inflammation, and hypersecretion of certain anabolic hormones, such as insulin, during obesity. The repression of hepatic AMPK activity permits the transition from simple steatosis to hepatocellular death; thus, activation might ameliorate multiple aspects of NASH. Here we review the pathogenesis of NAFLD and the impact of AMPK activity state on hepatic steatosis, inflammation, liver injury, and fibrosis during the transition of NAFL to NASH and liver failure.

Effect of Carotenoids from Phaeodactylum tricornutum on Palmitate-Treated HepG2 Cells

Non-alcoholic fatty liver disease represents the most common liver disease and is characterized by an excess of lipid accumulation in hepatocytes, mainly stored as triglycerides. Phaeodactylum tricornutum is a marine microalga, which is rich in bioactive molecules known to be hepatoprotective, such as n-3 long-chain polyunsaturated fatty acids and fucoxanthin. The aim of this study was to investigate the effects of a carotenoid extract from P. tricornutum in a cellular model of non-alcoholic fatty liver disease induced by palmitate treatment. The combined effects of carotenoids and lipids, especially n-3 long-chain polyunsaturated fatty acids, were also investigated by using a total lipophilic extract. HepG2 cells were exposed for 24 h to 250 µM palmitate with or without the addition of carotenoid extract (6 μg/mL) or total lipophilic extract (100 μg/mL). The addition of carotenoid extract or total lipophilic extract prevented the accumulation of triglycerides, total cholesterol and cholesterol esters. The carotenoid extract and total lipophilic extract also decreased the mRNA expression levels of genes involved in lipogenesis (ACACA, FASN, SCD and DGAT1) and cholesterol esterification (ACAT1/SOAT1). In addition, the total lipophilic extract also downregulated the LXR/NR1H3 and SREBF1 genes, which are involved in lipogenesis regulation. By contrast, the carotenoid extract increased the mRNA level of CPT1A, a β-oxidation related gene, and reduced the lipid droplet accumulation. In conclusion, this study highlights the preventive effects against non-alcoholic fatty liver disease of the two microalga extracts.

Novel antisense inhibition of diacylglycerol O-acyltransferase 2 for treatment of non-alcoholic fatty liver disease: a multicentre, double-blind, randomised, placebo-controlled phase 2 trial

BACKGROUND

Diacylglycerol-O-acyltransferase 2 (DGAT2) is one of two enzyme isoforms that catalyse the final step in the synthesis of triglycerides. IONIS-DGAT2_Rx is an antisense oligonucleotide inhibitor of DGAT2 that is under clinical investigation for the treatment of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). The aim of this trial was to examine the safety, tolerability, and efficacy of IONIS-DGAT2_Rx versus placebo in reducing liver fat in patients with type 2 diabetes and NAFLD.

METHODS

This double-blind, randomised, placebo-controlled, phase 2 study consisted of a 2-week screening period, a run-in period of up to 4 weeks, a 13-week treatment period of once-weekly dosing, and a 13-week post-treatment follow-up period. The study was done at 16 clinical research sites in Canada, Poland, and Hungary. Eligible participants were aged 18-75 years, had a body-mass index at screening between 27 kg/m² and 39 kg/m², haemoglobin A_1c (HbA_1c) levels from 7·3% to 9·5%, and liver fat content 10% or greater before randomisation, and agreed to maintain a stable diet and exercise routine throughout the study. Enrolled participants were stratified on the basis of liver fat content during the run-in period (<20% or ≥20%) and then centrally randomised (2:1) to receive once weekly subcutaneous injection of 250 mg IONIS-DGAT2_Rx or placebo for 13 weeks. Participants, investigators, funder personnel, and the clinical research organisation staff, including central readers of MRI scans, were all masked to treatment identity. The primary endpoints were the safety, tolerability, and pharmacodynamic effect of IONIS-DGAT2_Rx on hepatic steatosis, according to absolute reduction from baseline in liver fat percentage as quantified by MRI-estimated proton density fat fraction and assessed in the per-protocol population. Pharmacodynamic performance was determined in the per-protocol population by the change in liver fat content from baseline to 2 weeks after the last dose. The per-protocol population included all randomised participants who received at least ten doses of study drug, with the first four doses administered in the first 5 weeks, did not miss more than three consecutive weekly doses, and who had no protocol deviations that might affect efficacy. All randomised participants who received at least one dose of study drug were included in the safety analysis. This study is registered with ClinicalTrials.gov, NCT03334214.

FINDINGS

Between Nov 3, 2017, and Nov 28, 2018, we screened 173 people for eligibility. 44 were enrolled and randomly assigned to receive either IONIS-DGAT2_Rx (29 participants) or placebo (15 participants). After 13 weeks of treatment, the mean absolute reduction from baseline was -5·2% (SD 5·4) in the IONIS-DGAT2_Rx group compared with -0·6% (6·1) in the placebo group (treatment difference -4·2%, 95% CI -7·8 to -0·5, p=0·026). Reductions in liver fat were not accompanied by hyperlipidaemia, elevations in serum aminotransferases or plasma glucose, changes in bodyweight, or gastrointestinal side-effects compared with placebo. Six serious adverse events occurred in four patients treated with IONIS-DGAT2_Rx. No serious adverse events were reported in the placebo group. One of four patients reported three serious adverse events: acute exacerbation of chronic obstructive pulmonary disease, cardiac arrest, and ischaemic cerebral infarction, each considered severe and not related to study drug. Three of four patients reported one serious adverse event of increased blood triglycerides (severe, unrelated to study drug), deep-vein thrombosis (severe, unlikely to be related to study drug), and acute pancreatitis (mild, unrelated to study drug).

INTERPRETATION

Our results suggest that DGAT2 antisense inhibition could be a safe and efficacious strategy for treatment of NAFLD and support further investigation in patients with biopsy-proven NASH. Based on the pharmacological target, the response to treatment observed in this study population could extend to the broader population of patients with NAFLD.

FUNDING

Ionis Pharmaceuticals.

Recent development in acetyl-CoA carboxylase inhibitors and their potential as novel drugs

Acetyl-CoA carboxylase (ACC), a critical enzyme in the regulation of fatty acid synthesis and metabolism, has emerged as an attractive target for a plethora of emerging diseases, such as diabetes mellitus, nonalcoholic fatty liver disease, cancer, bacterial infections and so on. With decades of efforts in medicinal chemistry, significant progress has been made toward the design and discovery of a considerable number of inhibitors of this enzyme. In this review, we not only clarify the role of ACC in emerging diseases, but also summarize recent developments of potent ACC inhibitors and discuss their molecular mechanisms of action and potentials as novel drugs as well as future perspectives toward the design and discovery of novel ACC inhibitors.

Treatment of non-alcoholic fatty liver disease - Current perspectives

Therapeutics aimed at treating non-alcoholic fatty liver disease (NAFLD) target the pathogenic process from deranged metabolism leading to steatosis to cell stress and death, leading to a cascade of inflammation and fibrosis, ultimately culminating into cirrhosis. The development of drugs for management of NAFLD has bloomed over the past decade, although at present there is no approved pharmacological agent for its management. Not all patients with the disease progress to cirrhosis and decompensation; hence, treatment specifically is provided for those with a high risk of progression such as those with biopsy-proven steatohepatitis or fibrosis. Along with disease-specific management, all patients must receive therapies directed at risk factors such as dyslipidemia, insulin resistance, type 2 diabetes mellitus and obesity. Comorbidities such as cardiovascular disease, sleep apnoea and chronic kidney disease need management. A current perspective on the therapeutic options is detailed in this review.

The Intricate Relationship between Type 2 Diabetes Mellitus (T2DM), Insulin Resistance (IR), and Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) remain as one of the most global problematic metabolic diseases with rapidly increasing prevalence and incidence. Epidemiological studies noted that T2DM patients have by two-fold increase to develop NAFLD, and vice versa. This complex and intricate association is supported and mediated by insulin resistance (IR). In this review, we discuss the NAFLD immunopathogenesis, connection with IR and T2DM, the role of screening and noninvasive tools, and mostly the impact of the current antidiabetic drugs on steatosis liver and new potential therapeutic targets.

FGF21: An Emerging Therapeutic Target for Non-Alcoholic Steatohepatitis and Related Metabolic Diseases

The rising global prevalence of obesity, metabolic syndrome, and type 2 diabetes has driven a sharp increase in non-alcoholic fatty liver disease (NAFLD), characterized by excessive fat accumulation in the liver. Approximately one-sixth of the NAFLD population progresses to non-alcoholic steatohepatitis (NASH) with liver inflammation, hepatocyte injury and cell death, liver fibrosis and cirrhosis. NASH is one of the leading causes of liver transplant, and an increasingly common cause of hepatocellular carcinoma (HCC), underscoring the need for intervention. The complex pathophysiology of NASH, and a predicted prevalence of 3-5% of the adult population worldwide, has prompted drug development programs aimed at multiple targets across all stages of the disease. Currently, there are no approved therapeutics. Liver-related morbidity and mortality are highest in more advanced fibrotic NASH, which has led to an early focus on anti-fibrotic approaches to prevent progression to cirrhosis and HCC. Due to limited clinical efficacy, anti-fibrotic approaches have been superseded by mechanisms that target the underlying driver of NASH pathogenesis, namely steatosis, which drives hepatocyte injury and downstream inflammation and fibrosis. Among this wave of therapeutic mechanisms targeting the underlying pathogenesis of NASH, the hormone fibroblast growth factor 21 (FGF21) holds considerable promise; it decreases liver fat and hepatocyte injury while suppressing inflammation and fibrosis across multiple preclinical studies. In this review, we summarize preclinical and clinical data from studies with FGF21 and FGF21 analogs, in the context of the pathophysiology of NASH and underlying metabolic diseases.