The US Food and Drug Administration (FDA) has granted breakthrough therapy designation to Arrowhead Pharmaceuticals’ plozasiran, an investigational RNA interference (RNAi) therapeutic.

Plozasiran is intended for use as an adjunct to diet to cut down triglycerides in adults with familial chylomicronemia syndrome (FCS), a rare genetic disease.

The designation speeds up the development and review of drugs for serious conditions, where initial clinical evidence suggests significant improvement over existing treatments.

Plozasiran reduces the production of apolipoprotein C-III (APOC3), a key regulator of triglyceride metabolism.

High levels of APOC3 can lead to increased triglyceride levels in the blood, a characteristic of FCS.

In clinical studies, plozasiran has shown promising results by reducing triglycerides and other atherogenic lipoproteins in patients with FCS, severe hypertriglyceridemia (SHTG) and mixed hyperlipidaemia.

The safety profile of plozasiran was also found to be favourable, with treatment-emergent adverse events generally reflecting the comorbidities and underlying conditions of the study populations.

The SUMMIT programme, which includes multiple clinical studies such as the PALISADE Phase III study for FCS patients, the SHASTA studies for SHTG patients, and the MUIR and CAPITAN studies for mixed hyperlipidaemia patients, is investigating plozasiran.

Arrowhead also plans to submit a new drug application for plozasiran to the FDA by the end of 2024 and will seek regulatory approval from additional global authorities thereafter.

Plozasiran has also been granted orphan drug designation and fast track designation by the FDA and orphan drug designation by the European Medicines Agency.

Arrowhead Pharmaceuticals’ president and CEO Chris Anzalone stated: “There are currently no FDA-approved therapies to specifically treat FCS, leaving physicians with very few options to help their patients.

“Results from clinical studies of investigational plozasiran have been highly encouraging and strongly supportive of further development and commercialisation in multiple patient populations. Receiving FDA breakthrough therapy designation for plozasiran provides important benefits and the potential to expedite the process of getting plozasiran to the patients who need it.”

The latest development comes after the company announced the advancement of two RNAi-based candidates to clinic obesity treatment.