A RANDOMIZED, PLACEBO-CONTROLLED PHASE 3 STUDY OF OLEZARSEN IN PATIENTS WITH FAMILIAL CHYLOMICRONEMIA SYNDROME: THE BALANCE TRIAL

Abstract

Therapeutic Area: Pharmacologic Therapy Background: Familial chylomicronemia syndrome (FCS) is a rare genetic disorder of lipoprotein lipase deficiency that results in severe hypertriglyceridemia and an increased risk of potentially life-threatening acute pancreatitis (AP). Decreasing high plasma levels of apolipoprotein C-III (apoC-III) reduces hypertriglyceridemia. Olezarsen is an investigational ligand-conjugated antisense oligonucleotide targeted to hepatic APOC3 mRNA to reduce triglycerides (TG). Methods: Balance is a Phase 3, multicenter, randomized, double-blind, placebo-controlled trial in 66 patients with genetically confirmed FCS and fasting TG ≥880 mg/dL at screening. Patients were advised to consume <20g fat/day and randomized 2:1 to olezarsen (50 mg or 80 mg) or placebo sc every 4 weeks for 53 weeks. The two primary endpoints were the placebo-adjusted % change in fasting TG from baseline to 6-months for (1) olezarsen 80 mg and (2) olezarsen 50 mg. Secondary endpoints included change in 12-month TG and apoC-III levels, and incidence of independently adjudicated AP events. Results: At baseline, TG levels were ∼2600 mg/dL and 47/66 (71%) of FCS patients had a history of AP. Placebo-corrected TG levels at 6 months were significantly reduced in olezarsen 80 mg (-43.5%, P=0.0009), and were numerically lower in the olezarsen 50 mg group (-22.4%, P=0.0775). Placebo-corrected TG levels at 12 months were reduced -59.4% in the olezarsen 80 mg group and -43.8% in the olezarsen 50 mg group. ApoC-III levels were reduced in both dose groups at 6 months (olezarsen 50 mg: -65.5%; olezarsen 80 mg: -73.7%) and 12 months (olezarsen 50 mg: -77.1%; olezarsen 80 mg: -81.3%). During 53 weeks of randomized treatment, 11 episodes of AP occurred in 23 patients on placebo versus 2 episodes in 43 olezarsen-treated patients (1 in 50 mg and 1 in 80 mg group). A favorable safety and tolerability profile was noted, with more treatment emergent adverse events (TEAEs) and serious TEAEs in the placebo group. No serious TEAEs were related to study drug. Conclusions: In patients with FCS, olezarsen 80 mg significantly reduced TG levels and both olezarsen 50 and 80 mg groups demonstrated a marked reduction in AP events with a favorable safety and tolerability profile.