Ionis announces positive olezarsen topline results from Phase III study in people with familial chylomicronemia syndrome

The trial met its primary efficacy endpoint with a statistically significant reduction in triglyceride (TG) levels with the olezarsen 80 mg monthly dose at six months compared to placebo (p=0.0009); triglyceride lowering continued to improve at 12 months. In addition, olezarsen 80 mg showed a 100 percent reduction in acute pancreatitis events compared to placebo (0 events for olezarsen versus 11 events for placebo), a key secondary endpoint.

Treatment with olezarsen 80 mg resulted in a greater than 75% reduction in apoC-III, a protein produced in the liver that regulates TG metabolism in the blood. In addition to the 80 mg monthly dose, the study also evaluated a lower 50 mg monthly dose. Olezarsen demonstrated a dose-dependent effect, with both study doses showing a substantial reduction in pancreatitis. The lower 50 mg dose did not reach statistical significance at six months on the primary endpoint of triglyceride lowering (p=0.0775).

Olezarsen demonstrated a favorable safety and tolerability profile in the study. There were more adverse events in the placebo group compared to the olezarsen groups, primarily due to pancreatitis events. The majority of adverse events in the olezarsen groups were mild in severity. There was a low incidence of injection site reactions. No hepatic or renal toxicity events occurred and there were no clinically meaningful platelet reductions. One death was reported in the study, which was deemed as not related to study drug.

About the Balance Study: The global, multicenter, randomized, double-blind, placebo-controlled Phase III Balance study (NCT04568434) enrolled 66 patients aged 18 and older with confirmed FCS. Patients in the study received background therapies including statins, fibrates and omega-3 fatty acids. Patients were randomized in a 1:1:1 ratio to receive olezarsen 80 mg or 50 mg or placebo via subcutaneous injection once every four weeks for 53 weeks. The primary endpoint was the percent change from baseline in fasting triglyceride levels at six months compared to placebo. Secondary endpoints included triglyceride levels at 12 months and adjudicated acute pancreatitis event rate.