Shares in Vertex leapt more than 50% in pre-market trading on Tuesday after its treatment for cystic fibrosis showed strong promise in late-stage trials, thus taking a giant leap closer to regulatory filing.

The firm said that its therapy - a combination of the drugs lumacaftor and Kalydeco (ivacaftor) - induced statically significant improvements in lung function compared to placebo in patients aged 12 years and above with two copies of a particular gene mutation known as F508del.

In the Phase III programme, mean absolute improvements in lung function (percent predicted forced expiratory volume in one second, or ppFEV1) of between 2.6 and 4.0 percentage points from baseline compared to placebo were observed, with mean relative improvements of 4.3% to 6.7%.

This may seem on the low side, but if this effect is sustained long-term if could make a real difference to patents, given that, on average, those with two copies of the F508del can currently expect to lose nearly two percent of their lung function each year.

Secondary endpoints also met

Data from a pre-specified pooled analysis also showed improvements across multiple key secondary endpoints, with significant reductions in the rates of pulmonary exacerbations and improvements in both body mass index and the proportion of patients with at least a 5% relative improvement in lung function, the firm said.

"The significant improvements in pulmonary exacerbations are particularly important given the potential for these events to result in hospitalisations, permanent lung damage and the need for additional treatment with antibiotics and other medicines," noted lead investigator Bonnie Ramsey, Professor of Paediatrics, University of Washington School of Medicine, Director of the Center for Clinical and Translational Research at Seattle Children's Research Institute. 

First to address underlying cause

"The combination of lumacaftor and ivacaftor is the first regimen designed to address the underlying cause of CF for people with the most common form of the disease, and based on these data, we plan to move as fast as possible to submit applications for approval of this combination regimen in countries around the world," added Jeffrey Chodakewitz, Chief Medical Officer at Vertex. 

On the back of the data, Vertex said it plans to submit regulatory applications for approval in multiple countries, including in the US and Europe, in the fourth quarter of 2014 for people with CF ages 12 and older who have two copies of the F508del mutation.