Volanesorsen, an Antisense Oligonucleotide to Apolipoprotein-CIII, Decreases Triglycerides and Increases Lipoprotein Lipase Activity in Partial Lipodystrophy

Partial lipodystrophy syndromes (PL) involve selective deficiency of adipose tissue, with regional deficiency of fat in the lower extremities and preservation or even excess fat in the face and neck. Clinical features typical of PL include severe insulin resistance, diabetes mellitus, hypertriglyceridemia and non-alcoholic fatty liver disease. Apolipoprotein CIII (Apo-CIII) is elevated in PL, and is thought to contribute to high TG by inhibiting lipoprotein lipase (LPL). However, prior studies of this drug in patients with LPL mutations demonstrated LPL-independent mechanisms of TG-lowering. We hypothesized that Volanesorsen, an antisense oligonucleotide (ASO) to apo-CIII, would decrease apo-CIII, increase LPL activity, and lower TG in PL. We further hypothesized that Volanesorsen would improve insulin resistance and glycemia by directing free fatty acids (FFA) into adipose tissue, rather than ectopic sites (e.g. liver) associated with insulin resistance. Five adults with PL and TG ≥500 mg/dL or TG≥200 with A1c >7.0% were enrolled in a 16-week placebo-controlled, randomized, double blind study of Volanesorsen, 300 mg SC weekly, followed by a 1-year open label extension. Here, we report within-subject effects of Volanesorsen lipids, glycemia and lipolysis, before and after 16 weeks of active drug. From week 0 to week 16, apoC-III decreased from 380 (246, 600) to 75 (26, 232) ng/mL, TG decreased from 503 (330, 1040) to 116 (86, 355) mg/dL; and LPL activity measured in post-heparin plasma utilizing the subject’s serum as activator increased from 22.0±3.0 to 35.5±5.9 nEq/ml/min. Free fatty acid turnover (measured by palmitate tracer studies) decreased from 0.41 (0.35, 0.45) to 0.25 (0.23, 0.29) mg/kg/min. There was no change in A1c (8.4±1.2 to 8.3±0.9%), however there was a decrease in HOMA-IR from 26 (20, 54) to 13 (9, 43) and an increase in peripheral insulin sensitivity (glucose infusion rate during euglycemic hyperinsulinemic clamp, 120 mU/m(2)/min) from 3.6±2.4 to 4.4±1.5 mg/kgFFM/min and in hepatic insulin sensitivity (% suppression of hepatic glucose production during clamp) from 78±19 to 90±13%. Adverse events include injection site reactions and decreased platelets. Volanesorsen decreased apo-CIII and triglycerides, at least in part through an LPL dependent mechanism, and may improve insulin resistance.