CF Foundation Invests Up to $8.4M in SpliSense for the Development of Potential Rare Mutation Therapy

Today, the Cystic Fibrosis Foundation announced that it will invest up to $8.4 million in SpliSense's Series B funding round to develop an antisense oligonucleotide therapy for people with cystic fibrosis who have splicing mutations and potentially other rare mutations.

May 13, 2021 | 4 min read

BETHESDA, Md. -- Today, the Cystic Fibrosis Foundation announced that it will invest up to $8.4 million in SpliSense's Series B funding round to develop an antisense oligonucleotide (ASO) therapy for people with cystic fibrosis who have splicing mutations and potentially other rare mutations. The investment is part of the Foundation's Path to a Cure, a research agenda to accelerate treatments for the underlying cause of cystic fibrosis for every person with CF.

The CF Foundation's funding will support SpliSense's splicing mutation correction program, including preclinical development and a Phase 1/2a clinical trial to test the safety and tolerability of the ASO as a potential treatment for people with the splicing mutation 3849+10Kb C-to-T. The objective is to generate a proof-of-concept for the ASO technology in cystic fibrosis. If the trial is successful, it could potentially validate other similar therapeutic approaches in SpliSense's pipeline that address rare mutations in cystic fibrosis which do not respond to current therapies that target the underlying cause of CF.  

“This agreement will enable the exploration of synthetic antisense oligonucelotides as a potential treatment for CF in the clinic, opening exciting new opportunities for therapeutic development and further diversifying the approaches we are pursuing as part of our Path to a Cure,” said William Skach, MD, executive vice president and chief scientific officer for the CF Foundation. “As such, these studies will provide important information for the future development of these potential therapies for additional people with rare mutations.”

Splicing mutations disrupt the production of functional CFTR messenger RNA(mRNA), which is needed to make CFTR proteins. As a result, splicing mutations block the synthesis of normal CFTR proteins. If successful, this potential therapy would enable the creation of a full-length normal CFTR protein, helping restore the proper balance of salt and fluids in the lungs to improve lung function.

A splicing mutation occurs when there is an alteration in the DNA sequence that changes the instructions needed to properly generate mRNA. Oligonucleotides work by binding to the RNA molecule and correcting these instructions.  Oligonucleotides, including ASOs, provide a potential therapeutic approach for several types of CFTR mutations and are already used in the treatment of spinal muscular atrophy, certain forms of muscular dystrophy, and other genetic diseases.

SpliSense's technology is based on the research of Professor Batsheva Kerem from the Hebrew University of Jerusalem. Professor Kerem was part of the team that identified and cloned the CFTR gene which, when mutated, is responsible for causing cystic fibrosis. 

The Foundation awarded $400,000 to SpliSense in 2017 to develop this ASO therapy.

About the Path to a Cure

The CF Foundation launched its $500 million Path to a Cure initiative in October 2019. This initiative centers around three core strategies to address the underlying cause of CF: repairing broken CFTR protein, restoring CFTR protein when none exists, and fixing or replacing the underlying genetic mutation to address the root cause of CF. Each approach requires a different set of scientific tools and knowledge, leading the Foundation to bring together researchers and industry leaders from a range of disciplines to advance multiple areas of research in parallel. Learn more about the Path to a Cure and related funding opportunities on

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

Media Contact

Ashley Mahoney
Phone: 240-200-3754

Industry Contact

Lindsey Beaman
Phone: 240-200-3780

Share this article
Research | About the CF Foundation | Our Research Approach
Recent news
Cystic Fibrosis Community Perspectives Influence Future of CF Care Model
News | 4 min read
CF Foundation Adapts Registry Reporting to New Race-Neutral Standards
News | 5 min read
Nearly 350 Advocates Urge Congressional Action During 17th Annual March on the Hill
News | 3 min read
Stay up to date with The Foundation

Sign up for our newsletter to get all of the latest news from The Foundation right in your inbox.