New Company Sionna Therapeutics Aims to Develop Novel CF Therapies

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

Share this article:

Share article via email
CF gene therapy | Cystic Fibrosis News Today | illustration of money growing on plant

Sionna Therapeutics, a life sciences company that is developing a pipeline of experimental treatments for cystic fibrosis (CF), has announced its official launch following the closing of a $111 million Series B financing.

The company is aiming to treat the underlying cause of CF.

“Our mission at Sionna is to significantly improve the health and quality of life for people who continue to suffer from the life-long consequences and burden of living with CF,” Mike Cloonan, president and CEO of Sionna, said in a press release.

Previous investors RA Capital, TPG’s The Rise Fund, Atlas Venture, and the Cystic Fibrosis Foundation (CFF) have joined this funding round, with new investors led by OrbiMed.

The CFF invested $5 million, the foundation announced in a separate press release.

Recommended Reading
CFF grant | Cystic Fibrosis News Today | CRISPRi | illustration of hand with money

CFF Awards $15.9M to Eloxx for Clinical Development of ELX-02

“With this financing, our strong syndicate, and our experienced and talented team, we are excited to launch Sionna and are focused on advancing the first compounds from our differentiated pipeline into the clinic,” Cloonan said.

Cystic fibrosis is caused by mutations in the gene CFTR — in full, cystic fibrosis transmembrane conductance regulator — which provides instructions for making the CFTR protein. This protein normally sits at the surface of cells and functions like a gate, regulating the flow of water and salt molecules in and out of the cell.

Mutations in the CFTR gene in CF can lead to the production of a CFTR protein that cannot function correctly, which ultimately results in abnormally thick, sticky mucus and other disease symptoms.

The most common CF-causing mutation is called F508del, which is present in about 90% of CF patients. When a CFTR gene carrying the F508del mutation is “read” to produce a protein, the resulting CFTR protein has abnormalities in a specific region called the first nucleotide-binding domain (NBD1).

Specifically, the F508del mutation causes the NBD1 region to fold incorrectly. Proteins like CFTR need to be folded into a specific configuration in 3D space in order to function properly.

Sionna Therapeutics is developing a pipeline of novel small molecules that are designed to bind to the NBD1 region of the CFTR protein. The goal is to stabilize the mutated region, ultimately helping to restore CFTR function.

“NBD1 is a well-known and researched target, but it has been considered undruggable until now,” Cloonan said. “Based on our focused efforts and continued progress on NBD1, we see the potential to normalize CFTR function in the vast majority of people with CF.”

The company, founded in 2019, plans to submit an application to conduct clinical testing for its first NBD1-targeted program, deemed SION-638, within the next year.

“We continue to support Sionna’s novel approach in addressing the underlying cause of cystic fibrosis because we are committed to developing additional therapeutic options for people living with cystic fibrosis,” said Michael Boyle, MD, president and CEO of the Cystic Fibrosis Foundation.

The foundation says this investment has brought its total funding for F508del research, since 2011, to more than $38 million.