Today, more than 30,000 people in the US are living with cystic fibrosis (CF) – a hereditary condition characterized by thick sticky mucus that clogs airways and traps germs, leading to infections, inflammation, and other complications. CF is caused by a defective cystic fibrosis transmembrane conductance regulator (CFTR) protein. A class of drugs called CFTR modulators correct the protein’s action, but medications developed prior to last year had only been effective in people with highly specific mutations. A new combination drug, FDA approved in October 2019, is providing CF relief for patients with the most common CF gene mutation (F508 del) – estimated to represent 90% of individuals living with the disease.