News & Events > Novel Approach Allows Expansion of Indication for Cystic Fibrosis Drug

News & Events > Novel Approach Allows Expansion of Indication for Cystic Fibrosis Drug

The Division of Drug Information (DDI)- serving the public by providing information on human drug products and drug product regulation by FDA.

Typically, when FDA approves an expansion of the indication for a drug, it means that additional clinical data have shown the drug can safely and effectively treat patient populations other than those for which it was originally intended. But collecting additional clinical data is sometimes very difficult, especially with rare diseases. Patient populations are small and are often scattered throughout the country or the world, and therefore hard to access.

In the case of the drug Kalydeco (ivacaftor)—a drug that works in patients with specific mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene that cause cystic fibrosis (CF)—expansion of the indication was possible, thereby offering a disease-modifying treatment option to hundreds of patients living with CF, despite not having additional clinical data. To approve the indication expansion, a novel approach was used that relied on evidence from laboratory-based in vitro assay data. These data gave us sufficient information to determine whether certain populations with CF would likely respond to the drug.

Nearly 2,000 known mutations can affect the CFTR gene, which encodes for a protein that controls the movement of salt and water in and out of the body’s cells. About 300 mutations of these mutations result in CF. Certain mutations can cause more severe disease than others.

Kalydeco was previously approved for use in patients with one of 10 different types of mutations in the CFTR, which occur in about 8 percent of CF patients. With the expanded indication, Kalydeco is now considered effective against 23 additional mutations. Moreover, the in vitro data also were able to identify types of CFTR mutations that were NOT responsive to the drug. There is value in knowing who will likely not benefit from the drug, and this information is also included in the new labeling.

For more information, please visit: Kalydeco.