FDA Rejects Expanded Indication for Cystic Fibrosis Drug

New drug application for Kalydeco rejected for patients with 1 of 23 residual function mutations in the cystic fibrosis transmembrane conductance regulator gene.

Vertex Pharmaceuticals has received a complete response letter from the FDA for its supplemental new drug application for ivacaftor (Kalydeco).

The supplemental new drug application was for the use of Kalydeco as a treatment for cystic fibrosis in patients ages 2 or older who have 1 of 23 residual function mutations in the cystic fibrosis transmembrane conductance regulator gene.

In the complete response letter, the FDA stated that it cannot approve of the application in its current form. Vertex said it planned to meet with the FDA to determine the next steps.

"Our intention with this submission was to rapidly bring Kalydeco to additional people with cystic fibrosis who we believe may benefit," said Vertex Executive Vice President and Chief Medical Officer Jeffrey Chodakewitz in a press release. "We chose to pursue this approach given our strong belief in the science of cystic fibrosis and in the well-established safety of Kalydeco across many different groups of people with cystic fibrosis. We are disappointed by this decision and look forward to discussing with the FDA the next steps to bring Kalydeco to people with cystic fibrosis who have these residual function mutations."

The FDA approved Kalydeco last year as a treatment for patients with cystic fibrosis who have mutations in 1 of the following genes: G551D, G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, S549R, or R117H.

Dizziness is one of the most common adverse effects associated with the drug, but it can also cause high liver enzymes in the blood of some patients.