Sionna Therapeutics Goes Public with $219 Million IPO

Sionna Therapeutics, a Waltham biotech targeting cystic fibrosis, has closed its IPO, raising about $219 million. Sionna is a clinical-stage company seeking to revolutionize the current treatment paradigm for CF by developing novel medicines that normalize the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Sionna’s goal is to deliver differentiated medicines for people living with CF that can restore their CFTR function to as close to normal as possible by directly stabilizing CFTR’s nucleotide-binding domain 1 (NBD1), which the company believes is central to potentially unlocking dramatic improvements in clinical outcomes and quality of life for people with CF.

Leveraging more than a decade of the co-founders’ research on NBD1, the company is advancing a pipeline of small molecules engineered to correct the defects caused by a specific genetic mutation which resides in NBD1. Sionna is also developing a portfolio of complementary CFTR modulators that are designed to work synergistically with its NBD1 stabilizers to improve CFTR function. (Source: Sionna Therapeutics Website, 10 February, 2025)