Vertex Pharmaceuticals announced that the Food and Drug Administration (FDA) has issued a Complete Response Letter for the supplemental New Drug Application (sNDA) of Kalydeco (ivacaftor) in patients with cystic fibrosis (CF) ≥2 years old who have one of 23 residual function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

The letter stated the FDA’s decision to deny the application in its present form. Vertex intends to meet with the FDA to determine the next steps to take for this sNDA.

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Kalydeco, a CFTR potentiator, is currently approved for the treatment of CF in patients ≥2 years old who have one of 10 mutations in the CFTR gene (G551D, G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, S549R, or R117H).

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