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-DGAT2Rx 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-DGAT2Rx 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 A1c (HbA1c) 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-DGAT2Rx 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-DGAT2Rx 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-DGAT2Rx (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-DGAT2Rx 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-DGAT2Rx. 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.

Paradoxical increase in TAG and DAG content parallel the insulin sensitizing effect of unilateral DGAT1 overexpression in rat skeletal muscle.

BACKGROUND: The involvement of muscle triacylglycerol (TAG) storage in the onset of insulin resistance is questioned and the attention has shifted towards inhibition of insulin signalling by the lipid intermediate diacylglycerol (DAG). The enzyme 1,2-acylCoA:diacylglyceroltransferase-1 (DGAT1) esterifies a fatty acyl-CoA on DAG to form TAG. Therefore, the aim of the present study was to investigate if unilateral overexpression of DGAT1 in adult rat Tibialis anterior (TA) muscle will increase conversion of the lipid intermediate DAG into TAG, thereby improving muscle insulin sensitivity. METHODOLOGY/PRINCIPAL FINDINGS: The DGAT1 gene construct was injected in the left TA muscle of male rats on chow or high-fat (45% kcal) diet for three weeks, followed by application of one 800 V/cm and four 80 V/cm pulses, using the contralateral leg as sham-electroporated control. Seven days after electroporation, muscle specific insulin sensitivity was assessed with a hyperinsulinemic euglycemic clamp using 2-deoxy-[3H]glucose. Here, we provide evidence that unilateral overexpression of DGAT1 in TA muscle of male rats is associated with an increased rather than decreased DAG content. Strikingly, this increase in DAG content was accompanied by improved muscle insulin sensitivity. Interestingly, markers of muscle lipolysis and mitochondrial function were also increased in DGAT1 overexpressing muscle. CONCLUSIONS/SIGNIFICANCE: We conclude that unilateral DGAT1 overexpression can rescue insulin sensitivity, possibly by increasing DAG and TAG turnover in skeletal muscle. In case of a proper balance between the supply and oxidation of fatty acids in skeletal muscle, the lipid intermediate DAG may not exert harmful effects on insulin signalling.