A new drug intended to make it easier to clear mucus from the lungs of people with cystic fibrosis showed promising results in a recent Phase 2 clinical trial. The drug, called SPX-101, represents a new class of potential therapies that prevents mucus from becoming dehydrated so that it can be cleared from the lungs.
Mucociliary clearance, or the clearance of mucus from the lungs, is important for people with CF because their abnormally thick and sticky mucus clogs the airways, making it difficult for them to breathe and to cough out germ-laden mucus.
SPX-101 is known as an ENaC modulator, a drug that is designed to decrease the number of sodium channels that are overactive in CF lung cells. Because water is attracted to sodium, blocking the overabsorption of sodium into airway cells allows more fluid to remain on the surface of the airway. This enables mucus to be better hydrated, thinner, and easier to cough out. Importantly, ENaC modulators are intended to be used for all types of CF mutations.
Results from the Phase 2 clinical trial of the inhaled drug SPX-101 showed a 5.2 percent absolute increase in forced expiratory volume (FEV₁) in people with CF who received the highest dose of the drug compared to those who received a placebo.
The Cystic Fibrosis Foundation awarded up to $5 million to the drug's maker, Spyryx Biosciences Inc., to support the development of SPX-101. The drug still needs to go through a successful Phase 3 clinical trial before it can be considered for approval by the U.S. Food and Drug Administration.
Two additional ENaC inhibitors (which work in different ways) from other companies also are in Phase 2 clinical trials.