There have been great advances in the treatment of cystic fibrosis, but nevertheless it remains a progressive, life‑shortening genetic disease as many patients still don’t reach normal function and continue to face infections, exacerbations, and impaired quality of life. Siona Therapeutics is building a new generation of small‑molecule therapies that directly stabilize the region most affected by the most common mutation underlying the disease for the roughly 90 percent of patients who carry the defect. We spoke to Mike Cloonan, CEO of Sionna, about its experimental therapy that stabilizes the misfolded protein at the heart of the disease, its exploration of combinations with existing and proprietary therapies, and its $219 million IPO in February, despite the difficult financing environment for development-stage biotechs.