Patent Dispute Erupts Between Arrowhead and Ionis Over RNAi Candidate for Rare Metabolic Disease

Arrowhead Pharmaceuticals has initiated legal action against Ionis Pharmaceuticals, challenging the latter's patent claims related to a potential rival treatment for familial chylomicronemia syndrome (FCS). The lawsuit, filed in the U.S. District Court for the District of Delaware, seeks to invalidate Ionis' patent assertions regarding Arrowhead's investigational drug plozasiran.

Plozasiran: A Potential First-in-Class Treatment

Plozasiran, an RNAi therapeutic developed by Arrowhead, aims to reduce the production of apolipoprotein C-III (APOC3) to lower triglycerides and restore lipid levels in patients with FCS. The drug candidate is currently under FDA review, with a decision expected by November 18. Plozasiran has already secured breakthrough therapy, orphan drug, and fast track designations from the FDA, highlighting its potential significance in treating this rare genetic disorder.

Legal Battle Over Patent Infringement

Arrowhead's lawsuit targets Ionis' claim that the commercialization of plozasiran would infringe on its patent No. 9,593,333, titled "Modulation of apolipoprotein C-III (APOC3) expression in lipoprotein lipase deficient populations." Christopher Anzalone, Ph.D., President and CEO of Arrowhead, stated, "Arrowhead has multiple issued U.S. patents that cover plozasiran for the treatment of patients with FCS based entirely on work developed internally at Arrowhead, which Ionis was not involved with and provided no contribution to whatsoever."

The legal action seeks a declaratory judgment to establish the invalidity of Ionis' patent in relation to the manufacturing or sale of plozasiran. Anzalone expressed concern over Ionis' actions, stating, "It is unfortunate and troubling that Ionis Pharmaceuticals is attempting to take action that clearly puts their corporate goals ahead of the needs of patients with familial chylomicronemia."

Market Implications and Industry Response

If approved, plozasiran would compete directly with Ionis' Tryngolza (olezarsen), which received FDA approval for FCS treatment in December 2024. Tryngolza, an antisense oligonucleotide, was the first treatment to gain FDA clearance for this rare metabolic condition and represents Ionis' first independently commercialized drug.

In response to the lawsuit, an Ionis spokesperson emphasized the company's commitment to the FCS community, stating, "We welcome new advances that can help raise awareness of FCS and improve the lives of people who are in need." The spokesperson also clarified, "Importantly, we are not seeking to block the launch of this new therapy to patients. We are confident in our IP around FCS and will vigorously defend our patent position."

As the pharmaceutical industry closely watches this legal battle unfold, the outcome could have significant implications for the treatment landscape of FCS and potentially impact future drug development in the rare disease space.