Vertex Corrects Earlier Interim Data

Vertex Pharmaceuticals Inc. (VRTX - Snapshot Report) recently corrected previously reported interim data (responder analysis) from a phase II study of VX-809 and Kalydeco. Vertex also provided some additional data from the study.

The interim data from the phase II study showed improvements in lung function in adults with cystic fibrosis (CF) who had two copies of the F508del mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The interim data was on 37 patients who were treated with VX-809 and Kalydeco and 11 patients with one or two copies of the F508del mutation receiving placebo.

Earlier this month, Vertex had provided interim data from the study revealing that approximately 46% patients in the VX-809 plus Kalydeco arm experienced at least 5% improvement in lung function from baseline, while 30% of patients in receiving the combination therapy experienced an improvement of at least 10% from baseline to day 56.

However, Vertex in its recent announcement, reported that approximately 35% (13/37) patients in the VX-809 plus Kalydeco arm experienced at least 5% absolute improvement in lung function from baseline and approximately 19% patients experienced an absolute improvement of at least 10% from baseline to day 56. The company also mentioned that the previously reported results were relative and not absolute.

Vertex also provided additional data from the interim analysis on patients with two copies of the F508del mutation. Patients treated with VX-809 and Kalydeco showed at least 8.5% absolute improvement in lung function, in comparison to placebo.

Moreover, people treated with placebo experienced an absolute decline of about 4.6% in lung function, whereas patients treated with the combination showed approximately 4% absolute improvement in lung function from the baseline to day 56.

Vertex intends to start a pivotal study of VX-809 and Kalydeco in patients with two copies of the F508del mutation, once final results are out and based on discussions with regulatory agencies. The company expects complete data to be available in mid-2012.

We remind investors that Kalydeco was approved in the US, in February 2012, for treating CF patients above 6 years of age. Vertex Pharma is set to gain approval of the drug for the same indication in the European Union (EU), with the European Committee for Medicinal Products for Human Use having given a positive opinion recently.

Our Take

The incorrect interim data from the phase II study of VX-809 and Kalydeco was disappointing. This led to a 10.9% fall in the company’s stock price.

We currently have a Neutral recommendation on Vertex Pharma. The stock carries a Zacks #3 Rank (Hold rating) in the short run.