Comparative efficacy and safety of olezarsen versus volanesorsen for familial chylomicronemia syndrome: a matching-adjusted indirect comparison

Background: Familial chylomicronemia syndrome (FCS) is a rare genetic disorder characterized by severe hypertriglyceridemia causing recurrent acute pancreatitis (AP). Since FCS is a genetic deficiency in functional lipoprotein lipase, conventional triglyceride-lowering therapies are ineffective in this metabolic disorder. Apolipoprotein C-III (apoC-III) inhibitors, including volanesorsen and olezarsen, have emerged as targeted treatments for FCS. Aim: To compare the efficacy and safety of olezarsen 80 mg every four weeks (Q4W) versus volanesorsen 300 mg weekly (QW) in patients with FCS using an anchored matching-adjusted indirect comparison. Materials & methods: Individual patient data from the Balance trial of olezarsen (n = 45) were weighted to match baseline characteristics reported in the APPROACH trial of volanesorsen (n = 66). Outcomes included percent change in fasting triglycerides (TG) and apoC-III at 26 and 52 weeks, and risks of AP events and adverse events at 52 weeks. Results: At 52 weeks, mean differences in fasting TG and apoC-III were -27.4% (95% CI: -69.4, 14.5) and -21.3% (95% CI: -61.9, 19.3). Relative risks of AP, treatment-emergent adverse events, and serious adverse events were 0.23 (95% CI: 0.01, 5.02), 0.87 (95% CI: 0.66, 1.13) and 0.50 (95% CI: 0.08, 3.26) at week 52. The rate ratio for AP events per patient-year was 0.06 (95% CI: 0.003, 1.41). No comparisons were statistically significant. Conclusion: In this matching-adjusted indirect comparison, no statistically significant differences in outcomes were observed between olezarsen and volanesorsen in patients with FCS. These findings provide important comparative context in a setting where head-to-head evidence is unavailable.