Corrected interim data from Vertex VX-809, KALYDECO combination Phase 2 study for CF

May 30 2012

Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX) 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 placebos announcement provides a correction to the responder analysis.

“The improvements in lung function seen to date in this study exceeded our expectations. We're continuing to move forward as quickly as possible toward a pivotal study of VX-809 and KALYDECO in people with two copies of the F508del mutation”

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.

The actual absolute improvements in lung function for these patients are: approximately 35 percent (13/37) experienced an absolute improvement of 5 percentage points or more and approximately 19 percent (7/37) experienced an absolute improvement of 10 percentage points or more from baseline to Day 56. As previously announced, none of the patients treated with placebo (0/11) achieved a 5 percentage-point or more mean absolute improvement in lung function from baseline to Day 56.

Additional data from the interim analysis are provided today for people with two copies of the F508del mutation. A mean absolute improvement in lung function of 8.5 percentage points was observed among those who were treated with VX-809 and KALYDECO compared to placebo.

These data are from a planned interim analysis that was conducted after approximately half of the patients completed 56 days of treatment.

"The improvements in lung function seen to date in this study exceeded our expectations. We're continuing to move forward as quickly as possible toward a pivotal study of VX-809 and KALYDECO in people with two copies of the F508del mutation," said Chris Wright, M.D., Ph.D., Vertex's Senior Vice President, Global Medicines Development and Medical Affairs.

Safety results are the same as those announced on May 7, 2012 and include data from all patients who had started treatment prior to this interim analysis. VX-809 was generally well tolerated alone and in combination with KALYDECO. The most common adverse events were pulmonary in nature. Most adverse events were mild or moderate in severity and comparable between treatment and placebo groups. The rate of serious adverse events was similar between treatment and placebo groups.