Vertex Corrects and Provides Additional Data from Recent Interim Analysis of Phase 2 Combination Study of VX-809 and KALYDECO™ (ivacaftor) in People with Cystic Fibrosis Who Have Two Copies of the F508del Mutation

- Corrected Data: Responder analysis showed 35% of patients experienced an absolute improvement in lung function (FEV1) of at least 5 percentage points and 19% had at least a 10 percentage-point improvement when treated with VX-809 and KALYDECO - Vertex Pharmaceuticals Incorporated

announced today a correction to the previously reported responder analysis, as well as additional data from, the recent interim analysis of an ongoing Phase 2 study of VX-809 and KALYDECO™ (ivacaftor) that showed significant improvements in lung function (forced expiratory volume in one second, FEV1) among adults with cystic fibrosis (CF) who have two copies (homozygous) of the most common mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, F508del. As previously announced, there was a statistically significant improvement in lung function (absolute change in percent predicted FEV1) across the combined treatment groups relative to baseline compared to placebo (p=0.002). Today's announcement provides a correction to the responder analysis (n=37) for the absolute improvement in lung function compared to baseline and, for the first time, provides the mean absolute improvement in lung function compared to placebo observed among patients who received VX-809 (200mg, 400mg, 600mg; QD) and KALYDECO (250mg; q12h). The data reported today and earlier this month are based on 37 patients who completed 56 days of treatment with VX-809 and KALYDECO and 11 patients with one or two copies of the F508del mutation who received placebo. Vertex will host a conference call for investors and media today, May 29, 2012 at 8:00 a.m. ET, to discuss the correction and additional data. On May 7, 2012, the company announced that approximately 46 percent (17/37) of patients with two copies of the F508del mutation experienced an improvement in lung function (FEV1) of 5 percentage points or more and approximately 30 percent (11/37) experienced an improvement of 10 percentage points or more from baseline to Day 56 when treated with the combination of VX-809 and KALYDECO. These results were relative improvements, not absolute improvements as originally reported.