Vertex Filing For Expanded Kalydeco Label Rejected By FDA
Big biotech Vertex Pharmaceuticals ( VRTX ) slid in trading Friday after the FDA rejected an expansion on the label of its best-selling drug. Vertex had applied for approval of its cystic-fibrosis drug Kalydeco, known generically as ivacaftor, in CF patients over the age of 2 who have one of 23 residual function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The drug is currently approved for 10 other CFTR mutations, covering about 4,000 patients globally. The new indication would have added about 1,500 in the U.S. and Europe. Vertex said it will meet with the FDA to determine the next steps, so it might yet resubmit the application with more data, which analysts said was rather lacking in the current filing. “This … was based on an atypical application since it did not contain actual clinical data for the drug’s safety and efficacy in these patient populations,” Leerink analyst Geoffrey Porges wrote in a research note. “Instead, the application was based on preclinical data for the activity of Kalydeco, and the FDA appears to have decided that it can’t approve the drug on this basis. “While normally such an approval would indeed require clinical data, these mutation populations are so small that such trials are a tall order (although not impossible).” Because of the sketchiness of the application, estimates of success on Wall Street were only about 50-50, according to RBC Capital Markets analyst Michael Yee. “This is not in the majority of analyst estimates (and was not in our estimates), so it’s not a big change,” he wrote in his research note. Vertex stock was down nearly 6% in midday trading on the stock market today , below 87.