Cystic Fibrosis Foundation announces positive early results for phase 2 clinical trial of VX-770

An oral compound to treat CF

Bethesda, MD, March 27, 2008 — The Cystic Fibrosis Foundation announced today that VX-770, an oral drug in development that targets a basic defect in CF, showed promising results in an ongoing Phase 2a clinical trial for patients who carry the G551D mutation of CF. The drug is being developed by Vertex Pharmaceuticals Incorporated.

Patients who took the drug for 14 days showed significant improvements in several key indicators of cystic fibrosis, including lung function, nasal potential difference measurements and sweat chloride levels. The findings suggest that VX-770 improves function of what is known as the faulty CFTR protein. This early data is promising and could have important implications for studies of other drugs in development.

This is the first time that any potential therapy has improved the abnormal sweat chloride (salt) levels in a person with CF. Excessive sweat chloride is a key clinical indicator of cystic fibrosis. The “sweat test” is the traditional diagnostic test for CF.

“These early results are an extraordinary endorsement of our hypothesis—that small molecules can correct the basic defect and affect the clinical indicators of cystic fibrosis,” said Robert J. Beall, Ph.D., president and CEO of the Foundation. “The emerging data for VX-770 represents the most exciting results we’ve seen from a Phase 2 trial and increase our confidence that we’re on the right track.”

The compound VX-770 resulted from a collaboration between the Foundation and Vertex. In 1998, the Foundation approached Aurora Biosciences (acquired by Vertex in 2001) and made an initial investment to use cutting-edge technology—known as high throughput screening—to find compounds to attack the core defect in CF. Since that time, the Foundation has invested $79 million in the project, and the two organizations have closely collaborated to advance VX-770 and a second CF compound, known as VX-809, through research and into development.