Ionis Pharmaceuticals' rare disease drug Olezarsen has been approved by the FDA.

The Food and Drug Administration (FDA) has approved Ionis Pharmaceuticals' drug Olezarsen for the treatment of rare genetic diseases, which is the company's first fully owned drug. Olezarsen has been approved for the treatment of familial chylomicronemia syndrome (FCS). Trial results released in April of this year showed that for moderate hypertriglyceridemia patients at high cardiovascular risk, Olezarsen can significantly reduce triglyceride, apolipoprotein B, and non-HDL cholesterol levels, with no major safety issues found. FCS is a severe and extremely rare genetic disease often caused by various single gene mutations. FCS results in extremely high triglyceride levels, usually exceeding 880mg/dL. This severe elevation can lead to various serious signs and symptoms, including acute and potentially fatal pancreatitis, chronic abdominal pain, diabetes, liver steatosis, and cognitive issues. Currently, treatment options for FCS are limited, with strict low-fat diet being the first-line approach. Olezarsen has been approved as an adjunct treatment to lower triglyceride levels in adult patients. Boosted by this news, Ionis Pharmaceuticals saw its stock rise nearly 7% in after-hours trading on Thursday. Ionis Pharmaceuticals stated that they will announce details of the drug's pricing during an investor call. CEO Brett Monia said, "We believe there are no obstacles on the supply side. We have produced and are ready." Monia added that patients still need to follow recommended dietary restrictions. However, BMO Capital Markets analyst Kostas Biliouris believes that, given the low prevalence of FCS and the entry of competing drugs into the market in the second half of next year, FCS treatment drugs will not be a major opportunity for Ionis Pharmaceuticals. According to US government data, fewer than 5,000 people in the US have FCS. Biliouris estimates that sales of Ionis Pharmaceuticals' FCS treatment drugs could reach up to $341 million.