Vertex Pharmaceuticals Incorporated (NASDAQ:VRTX) announced that it received a Complete Response Letter from theU.S. Food and Drug Administration (FDA) for its supplemental New Drug Application (sNDA) for the use of KALYDECO® (ivacaftor) in people with cystic fibrosis (CF) ages 2 and older who have one of 23 residual function mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The FDAdetermined that it cannot approve the application in its present form. Vertex plans to meet with the FDA to determine an appropriate path forward.

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

The sNDA is based on preclinical data for ivacaftor in residual function mutations, the established clinical profile of KALYDECO and on previously reported data from an exploratory Phase 2a study. In 19 of the 24 patients enrolled in this study, eight of the 23 mutations proposed in the sNDA were represented.

CF is caused by defective or missing cystic fibrosis transmembrane conductance regulator (CFTR) proteins resulting from mutations in the CFTR gene. The defective or missing proteins result in poor flow of salt (chloride) and water into and out of the cell in a number of organs, including the lungs. Chloride transport is a marker of the function of the CFTR protein at the cell surface. KALYDECO, which received the FDA’s Breakthrough Therapy Designation in 2013, is currently approved in the U.S. to treat people with CF ages 2 and older who have one of 10 mutations in the CFTR gene (G551D, G1244E, G1349D, G178R,G551S, S1251N, S1255P, S549N, S549R or R117H). As with the mutations for which KALYDECO is approved, this group of 23 residual function mutations is known to have some functional CFTR protein at the cell surface. This submission was also based on observed in vitro increases in chloride transport in response to ivacaftor in cells expressing CFTR. The presence of CFTR protein at the cell surface and increases in chloride transport are characteristics associated with clinical response to KALYDECO. (Original Source)

Shares of Vertex are falling nearly 5% in pre-market trading. VRTX has a 1-year high of $143.45 and a 1-year low of $81.98. The stock’s 50-day moving average is $107.26 and its 200-day moving average is $120.31.

On the ratings front, Vertex has been the subject of a number of recent research reports. In a report released today, Leerink Swann analyst Howard Liang assigned a Buy rating on VRTX. Separately, on February 2, H.C. Wainwright’s Andrew Fein reiterated a Buy rating on the stock and has a price target of $155.

According to, which ranks over 7,500 financial analysts and bloggers to gauge the performance of their past recommendations, Howard Liang and Andrew Fein have a total average return of 20.0% and -4.0% respectively. Liang has a success rate of 54.8% and is ranked #114 out of 3621 analysts, while Fein has a success rate of 38.5% and is ranked #3053.

The street is mostly Bullish on VRTX stock. Out of 12 analysts who cover the stock, 8 suggest a Buy rating and 4 recommend to Hold the stock. The 12-month average price target assigned to the stock is $140.00, which implies an upside of 52.6% from current levels.

Vertex Pharmaceuticals Inc is engaged in the business of discovering, developing, manufacturing and commercializing small molecule drugs for patients with serious diseases in specialty markets.