Sionna Therapeutics – a clinical-stage life sciences company focused on developing highly effective and differentiated treatments for cystic fibrosis (CF) – announced the closing of a $182 million Series C funding to support the clinical development of first-in-class small molecules designed to fully restore the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein by stabilizing the first nucleotide-binding domain (NBD1).
The Series C funding round (which was upsized and oversubscribed) was led by Enavate Sciences with additional new investors Viking Global Investors and Perceptive Advisors, and participation by all existing investors, including RA Capital, OrbiMed, TPG’s The Rise Fund, Atlas Venture, the Cystic Fibrosis Foundation, funds and accounts advised by T. Rowe Price Associates, and Q Healthcare Holdings, LLC (a wholly owned subsidiary of QIA). And Sionna also announced that Edd Fleming, M.D., Executive Vice President of Commercialization at Enavate Sciences, is joining its Board of Directors.
CF is caused by mutations in the CFTR gene – which codes for an epithelial ion channel essential for producing healthy and freely flowing mucus in the airways, digestive system, and other organs. And the most common mutation in CFTR, ΔF508, causes NBD1 to unfold at body temperature and severely impairs CFTR function.
Sionna presented preclinical data such as what is pulled from the clinically predictive human bronchial epithelial cell (CFHBE) model that demonstrates its NBD1 stabilizers can restore ΔF508-CFTR maturation, trafficking, and function to wild-type levels when combined with complementary modulators. Plus, A Phase 1 clinical trial of its first clinical-stage NBD1 stabilizer SION-638 identified doses that are generally safe and well tolerated, and target exposure (based on the CFHBE assay) was achieved at all doses, with more time above target with a dose increase.
Sionna also nominated two additional NBD1 stabilizers from its second series, SION-451 and SION-719, and plans to advance both compounds to clinical trials this year pending results from ongoing Good Laboratory Practice (GLP) toxicology studies. And the company is continuing to advance the development of compounds targeting complementary mechanisms including SION-109, which targets NBD1’s interface with the CFTR intracellular loop 4 (ICL4) region; a Phase 1 clinical trial with SION-109 began in January 2024.
KEY QUOTES:
“We have deep experience in CF and a sharp focus on advancing the development of novel small molecules targeting NBD1 and complementary modulators that enable the potential for full restoration of CFTR function for most people living with CF. We are encouraged by the strong interest and validation from the excellent investors in our upsized Series C financing. This capital raise provides financial flexibility positioning us to execute our clinical development plan with funding through 2026 and multiple value-creating clinical readouts. We are also pleased to welcome Dr. Fleming to our Board and look forward to insights from his more than 30 years of experience in the health care industry.”
– Mike Cloonan, President and Chief Executive Officer of Sionna
