Abstract 12594: Pharmacodynamic Effect of ARO-APOC3, an Investigational Hepatocyte-targeted RNA Interference Therapeutic Targeting Apolipoprotein C3, in Patients With Hypertriglyceridemia and Multifactorial Chylomicronemia

Abstract

Background: Hypertriglyceridemia (HTG) increases the risk of acute pancreatitis and atherosclerosis. In a Phase 1 study (NCT03783377), single subcutaneous doses of investigational RNA interference (RNAi) therapeutic ARO-APOC3 (10, 25, 50, and 100 mg; N=24) demonstrated deep and prolonged reductions in apolipoprotein C3 (APOC3) and triglycerides (TG) and increases in HDL-C in healthy volunteers with good tolerability, compared with placebo (N=16). Purpose: We report initial results of the effects of ARO-APOC3 in patients with HTG (fasting TG ≥ 300 mg/dL) or multifactorial chylomicronemia (MCM; fasting TG ≥ 880 mg/dL). Methods: Up to 40 subjects with HTG and 20 subjects with MCM will receive ARO-APOC3 or placebo on days 1 and 29. Pharmacodynamic responses include serum APOC3, TG, and other lipid parameters reported up to week 4 prior to the 2 nd dose. Results: At the data cutoff (16 March 2020), the first 4 enrolled patients with HTG and 6 enrolled patients with MCM were administered ARO-APOC3 50 mg. ARO-APOC3 substantially reduced mean (range) APOC3 levels by 96% (88-99%) in both patient groups at Week 4 (Table). ARO-APOC3 substantially reduced mean (range) TG by 78% (67-87%) in HTG patients and by 92% (90-95%) in MCM patients at Week 4. Three of 4 HTG patients and 3 of 6 MCM patients had TG levels below 150 mg/dL. All MCM patients had TG ≤ 500 mg/dL. To date, ARO-APOC3 has been generally well tolerated with no reports of treatment-related serious or severe adverse events. Two of the 6 unblinded MCM patients experienced a transient ALT elevation to >3X ULN that returned to approximate pre-dose baseline by Day 113. Conclusions: Preliminary results indicate that a single dose of ARO-APOC3 reduces APOC3 levels by >90% and TG by ~80% 4 weeks after treatment in patients with HTG and MCM. The magnitude of treatment effect was similar in both populations and ARO-APOC3 had a favorable safety profile. Using RNAi to silence expression of APOC3 appears promising for treating patients with HTG and MCM.