Rare Daily Staff

Ionis Pharmaceuticals said it will discontinue development of its experimental inhaled antisense therapy for the rare lung disease cystic fibrosis.

In its first quarter earnings call, the company said it made the decision because of recent findings from a long-term preclinical toxicology study of Ionis-Enac-2.5-Rx. In October 2020, the company reported positive results from a phase 1 study, but it said while it believes it could work through the toxicology findings, it would represent a delay. It is also evaluating other programs in its pulmonary pipeline as a result.

Cystic fibrosis (CF) is a life-threatening disease affecting approximately 30,000 people in the U.S. and about 70,000 worldwide. Although CF is a multisystem disease, the main cause of morbidity and mortality is lung disease, characterized by small airway obstruction due to mucus accumulation, decreased mucus clearing and subsequent inflammation, infections and lung function decline.

IONIS-ENAC-2.5Rx is designed to reduce the expression of ENaC in the lung. ENaC is believed to be hyperactive in cystic fibrosis, which is caused by mutations in the cystic fibrosis transmembrane regulator gene.

“It’s going to take us time to figure out what that’s about. And due to the delays that are just associated with those types of investigations, we took a look at our emerging pipeline in pulmonary diseases,” said Ionis CEO Brett Monia. “And we think we have better targets to invest in that will bring greater value to the company.”

Photo: Brett Monia, CEO of Ionis

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