Ionis Pharmaceuticals has announced a major regulatory milestone for its investigational therapy olezarsen, as the U.S. Food and Drug Administration (FDA) has granted it Breakthrough Therapy designation for adults with severe hypertriglyceridemia (sHTG). The treatment is intended to be used alongside dietary modifications to reduce dangerously elevated triglyceride (TG) levels—defined as 500 mg/dL or higher—a condition associated with a significant risk of acute pancreatitis and cardiovascular complications.
Breakthrough Therapy designation is reserved for drugs that target serious or life-threatening conditions and have demonstrated substantial improvement over available therapies in preliminary clinical studies. For Ionis, the designation reflects strong confidence in olezarsen’s potential to address the unmet medical needs of patients with sHTG, a condition for which current therapies often fall short.
Sam Tsimikas, M.D., senior vice president of global cardiovascular development at Ionis, described the recognition as a validation of the science behind olezarsen. “The Breakthrough Therapy designation reflects the groundbreaking nature of the pivotal CORE and CORE2 study results, in which olezarsen significantly lowered triglycerides below the risk threshold of acute pancreatitis in the vast majority of patients,” he said. He noted that existing treatments typically lead to modest reductions in triglycerides and frequently fail to protect against sudden and potentially life-threatening pancreatitis attacks. “As the first investigational therapy for sHTG to significantly reduce acute pancreatitis events, olezarsen has the potential to change the treatment paradigm for this dangerous disease.”
The FDA’s decision is based on robust findings from the Phase 3 CORE and CORE2 trials, which evaluated olezarsen’s efficacy and safety across diverse patient groups. In both studies, patients receiving olezarsen achieved a placebo-adjusted reduction in triglyceride levels of up to 72%, a result described as highly statistically significant. Importantly, the therapy also delivered an 85% reduction in acute pancreatitis events, offering compelling evidence of clinical benefit beyond biomarker improvement.
Nearly 90% of trial participants treated with olezarsen reached triglyceride levels below 500 mg/dL—the accepted threshold for reducing the risk of acute pancreatitis. These notable outcomes were recognized by the broader medical community, with the data published in The New England Journal of Medicine and presented at the American Heart Association Scientific Sessions.
Ionis emphasized that olezarsen has demonstrated favorable safety and tolerability across trials, strengthening its potential as a first-in-class treatment option for individuals living with sHTG. The company is preparing to move rapidly toward regulatory submission and confirmed it remains on track to file a supplemental new drug application with the FDA before the end of the year.
If approved, olezarsen could become the first therapy to meaningfully reduce both triglyceride levels and acute pancreatitis events in sHTG—a development that may significantly shift current treatment standards and provide new hope for patients facing this high-risk condition.