Vertex Looks to Patient Subset as CF Drug Misses Mark in Latest Study

12/19/13Follow @benthefidler

The results are out from Vertex Pharmaceuticals’ (NASDAQ: VRTX) latest cystic fibrosis study. And while the Cambridge, MA-based company didn’t get what it was looking for, it still says the numbers are good enough to bring to the FDA next year.

Vertex announced the results of a late-stage study testing its cystic fibrosis drug, ivacaftor (Kalydeco), in patients with at least one copy of the so-called R117H gating mutation. The study failed to reach its main goal of showing that ivacaftor could significantly improve lung function in the group of 69 patients.

Vertex, however, still said that a pre-specified subset of patients 18 and over—a group that represented a majority of the patients in the study—did show enough of an improvement for the company to see if the FDA will approve the drug for patients in that age group with an R117H mutation. Specifically, Vertex said 50 of the 69 patients in the study were in this subset, and saw a relative improvement in lung function—as measured by their ability to force air out of their lungs for one second—of about 9.1 percent over the course of the 24-week study.

By comparison, 17 patients between 6 and 11 years old saw their lung function decline by an average of about 2.8 percent.

Vertex also tested two patients between the ages of 12 and 17, but didn’t report those data because the sample size was too small to make a statistical comparison.

“People with the R117H mutation exhibit a wide range of severity in their CF lung disease, but as patients get older, the disease often results in decreased lung function,” said Vertex senior vice president and chief medical officer Robert Kauffman, in a statement. “While we are disappointed that the study in people with the R117H mutation did not meet its primary endpoint, we are encouraged by the significant improvements in lung function and other measures of CF observed in the subset of patients ages 18 and older who had established lung disease.”

Indeed, it’s not the best-case scenario for Vertex, but it’s not the worst case either. About 300 people in the U.S. have the R117H mutation and are 18 and older, and ivacaftor, which is taken chronically, is priced at more than $300,000 per year, per patient. Vertex will meet with the FDA early next year to discuss an application for approval in this group of patients.

The study is the latest in a series of late-stage tests Vertex is running with the aim of expanding ivacaftor’s reach. The drug is already approved in the U.S. and European Union for people with the G551D gating mutation—about 2,000 patients worldwide, or 3 percent of the 70,000 patient CF population.

Earlier this year, Vertex took a small step when it hit its mark in a late-stage trial testing the drug in people with at least one non-G551D gating mutation. That amounts to about another 400 patients worldwide. A big test will come next year when it reveals the results of a combination study of ivacaftor and another CF drug it’s developing called VX-809 in patients with two copies of the F508del mutation—of which there about 30,000 patients worldwide.

Vertex’s stock climbed about 2 percent in early trading on Thursday.

Ben Fidler is Xconomy's Deputy Biotechnology Editor. You can e-mail him at bfidler@xconomy.com Follow @benthefidler

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