CF Foundation Provides Up to $8.5M to SpliSense to Support a Clinical Trial for a Potential Treatment for Splicing Mutations

The additional funding will support a Phase 2 clinical trial for an inhaled antisense oligonucleotide drug for people with cystic fibrosis who have the splicing mutation 3849+10Kb C-to-T.

April 3, 2024 | 3 min read

BETHESDA, Md. — The Cystic Fibrosis Foundation is investing up to $8.5 million in additional funds in SpliSense to continue clinical trials for its inhaled antisense oligonucleotide (ASO) drug for people with cystic fibrosis who have certain splicing mutations and potentially other rare mutations.

The Foundation's funding will support a planned Phase 2 clinical trial to test the efficacy of SpliSense’s inhaled ASO drug as a potential treatment for the lungs of people with the splicing mutation 3849+10Kb C-to-T. A recent Phase 1a study indicated the drug was safe and well tolerated.

“We continue to pursue diverse strategies to develop potential treatments for people with CF who can’t benefit from existing modulator therapies,” said Steven M. Rowe, MD, executive vice president and chief scientific officer at the Foundation. “Information from this study is key to advancing those efforts with a novel technology and will also provide valuable insight into the development of therapies for people with rare mutations.”

Splicing mutations disrupt the production of normal cystic fibrosis transmembrane conductance regulator (CFTR) RNA, resulting in dysfunctional CFTR proteins. SpliSense’s drug would work by binding to the RNA molecule and correcting the instructions to create healthy, full-length CFTR proteins, helping restore the proper balance of salt and fluids in the lungs of people with CF.

The objective of the clinical trial is to generate a proof-of-concept for ASO technology in cystic fibrosis. If the clinical trial is successful, it could validate other similar therapeutic approaches in SpliSense's pipeline that address rare CF mutations. 

In 2021, the Foundation invested $8.4 million in SpliSense to develop a therapy for splicing mutations, in addition to $400,000 the Foundation provided in 2017. All these investments are part of the Foundation’s $500 million Path to a Cure, an ambitious research initiative to accelerate treatments for everyone with CF and ultimately deliver a cure

About the Cystic Fibrosis Foundation

The Cystic Fibrosis Foundation is the world's leader in the search for a cure for cystic fibrosis. The Foundation funds more CF research than any other organization, and nearly every CF drug available today was made possible because of Foundation support. Based in Bethesda, Md., the Foundation also supports and accredits a national care center network that has been recognized by the National Institutes of Health as a model of care for a chronic disease. The CF Foundation is a donor-supported nonprofit organization. For more information, visit

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