CF Foundation Funds Expansion of Clinical Trial Program for Potential Nonsense Mutations Therapy

The Cystic Fibrosis Foundation is awarding up to $15.9 million in additional funding to Eloxx Pharmaceuticals Inc. to expand clinical studies of ELX-02, a potential therapy for people with CF who have nonsense mutations.

March 29, 2022 | 4 min read

Bethesda, Md. — Today, the Cystic Fibrosis Foundation announced an award to Eloxx Pharmaceuticals Inc. for up to $15.9 million in additional funding to support the expansion of its ongoing ELX-02 clinical program focused on developing therapies for people with CF who have nonsense mutations.

The Foundation previously provided up to $3.6 million in funding for Eloxx’s initial ELX-02 clinical studies. The new funding will enable the company to expand the studies to determine whether the combination of ELX-02 with a cystic fibrosis transmembrane conductance regulator (CFTR) modulator results in increased biological activity over ELX-02 alone.

“Despite therapeutic advances for many people with CF, therapies that target nonsense mutations are still urgently needed,” said Michael Boyle, MD, president and CEO of the Cystic Fibrosis Foundation. “We are aggressively funding the expansion of Eloxx’s clinical program to ensure we continue to improve our scientific understanding in this critical area of research.”

The award, which provides financial and scientific support to Eloxx, is part of the CF Foundation's $500 million Path to a Cure initiative to accelerate treatments for the underlying cause of CF and develop a cure. Current therapies have significantly improved the lives of many people living with CF, but there are still people — including those with nonsense mutations — who do not have an effective treatment for the underlying cause of their disease.

Nonsense mutations

Nonsense mutations (also known as “x” or “stop” mutations) cause cells to stop the production of the CFTR protein midway through the process, resulting in shortened, non-functional protein that the cell recognizes as defective and destroys. The investigational drug ELX-02 could potentially “read through” or bypass these premature stop signals in people with CF, resulting in the production of full-length functioning protein.

Laboratory data indicate that combining ELX-02 with CFTR modulators could increase the effectiveness of read through activity by several fold. The clinical program expansion, which is already enrolling, will investigate whether coupling the investigational drug ELX-02 with ivacaftor (Kalydeco®) makes it more effective. Results are expected by mid-2022.

Tony Durmowicz, MD, vice president of clinical development at the Cystic Fibrosis Foundation, said, “What we learn from these studies will be critically important for informing future research and drug development of therapies for these notoriously difficult-to-treat targets for years to come, including how data obtained from the lab may translate to the clinic.”

According to the Cystic Fibrosis Foundation Patient Registry, nearly 13% of people with CF in the U.S. have at least one nonsense mutation. Of that number, approximately 3% cannot benefit from any currently available therapy.

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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