A Treatment Suitable for Half of Cystic Fibrosis Patients?

Positive test results for Vertex Pharmaceuticals’ newest Phase 3 clinical trials may expand the population of cystic fibrosis patients suitable to take a Vertex-produced drug from only 4% to nearly 50%. “It’s going to potentially allow us to get a medicine to 22,000 patients around the world with the most common form of cystic fibrosis,” said Jeffrey Leiden, chief executive of Vertex, in a news report.

Two Vertex-sponsored Phase 3 clinical trials, TRANSPORT and TRAFFIC, each with over 550 patients, were completed, and scientific findings for the basis of the trials appeared in Journal of Cystic Fibrosis. The goal of the trials was to evaluate the combination of lumacaftor and ivacaftor in patients with cystic fibrosis of the F508del-CFTR mutation. Results were overwhelmingly positive for a number of patients.

One patient in particular is Aaron C. Stocks, a 28-year old cystic fibrosis patient from Frederick, Maryland. “About three weeks after I began taking this medicine [during testing], I went for a run and the difference was unbelievable,” said Stocks, as quoted in a recent article from the Boston Globe. “I wasn’t winded, I wasn’t tired, I just wanted to keep going.” Up until this point, Stocks, who is a case manager at the Cystic Fibrosis Foundation, “never thought that far ahead” in terms of starting a family with his wife, as approximately half of patients do not live past the age of 30. “This is life changing,” he said.

“My hair was standing up on my arms all morning when I heard about this,” said Joe O’Donnell, an active fund-raiser for cystic fibrosis along with his wife, Kathy. “This is a milestone day. It’s not the culmination. We’re in the seventh inning or the eight inning. We don’t have FDA approval, but we will get that. We fully expect the lives of these kids are going to be transformed.” The O’Donnells lost a son to cystic fibrosis when he was 12 years old in 1986.

To open this treatment for patients with the F508del-CFTR mutation, Vertex may file the combination treatment for approval in the United States and Europe by the end of the year. Ivacaftor is already marketed by Vertex under the name Kalydeco, and lumacaftor is an experimental compound. “It will be the first medicine that treats the underlying cause of the disease for those patients,” said Leiden. “Every improvement in lung function, every day they stay out of the hospital, every pound they gain, is meaningful.”

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Both patients and Vertex are benefiting from the news. The price of Vertex’s stock shares rose 40.4% to $93.53 on the Nasdaq exchange. Mark Schoenebaum, a biotechnology analyst for ISI Group in New York estimates Vertex’s annual sales may reach $5.5 billion if regulatory approval of the two-drug cocktail comes to fruition. “The data are good and will clearly support worldwide regulatory approval for this drug regimen,” wrote Schoenebaum in a note to investors. “I can’t see any reason why the vast majority of patients with the appropriate mutation will not want to take this regimen.”

As explained by a recent post on Cystic Fibrosis News Today, lumacaftor is a corrector for the CFTR protein, and ivacaftor is a potentiator for the CFTR protein. Ivacaftor can treat approximately 2,000 cystic fibrosis patients, which account for 4% of the disease population, by activating CFTR on the cell membrane. By using lumacaftor to help CFTR properly fold, Vertex may be able to help the majority of cystic fibrosis patients, raising the number to 22,000 to 30,000 patients. Shooting even higher is a three-drug cocktail from Vertex that may be able to treat another 17,000.

Also explained in the previous post, the results are more positive than what may have been expected. Patient lung function improved and the rate of pulmonary exacerbations dropped, despite any interaction between the drugs. “As a clinician and as a researcher, I was extremely excited to see the effect of this treatment not only on patients’ lung function but on [reducing] the frequency with which they become sick,” said Dr. Michael P. Boyle, director of the adult cystic fibrosis program at Johns Hopkins Hospital and one of the trial’s principal investigators. “We knew that if we were going to make a difference in cystic fibrosis, we had to be able to help people with the most common form of this disease.”