Vertex Pharmaceuticals Inc., maker of the first medicine to target the underlying cause of cystic fibrosis, gained the most ever after a combination of that drug and a second therapy improved patients’ breathing ability.
Vertex climbed 55 percent to $58.12 at the close of New York trading, its biggest increase since the company’s shares began trading publicly in 1991. The combination of Kalydeco, approved in January, and the experimental VX-809 improved lung function by at least five percentage points in 46 percent of patients in a mid-stage study, the Cambridge, Massachusetts-based company said today in a statement.
The results are from an interim review of 48 patients after 56 days. Vertex said it plans to start the third and final stage of clinical trials required for marketing approval, pending final data and talks with regulators. The patients in the treatment arm had two copies of the most-common cystic fibrosis-related gene mutation, called F508del.
“The company had been advising analysts to not expect a lung-function benefit in this trial; well, they were wrong,” said Mark Schoenebaum, an analyst with ISI Group in New York, in a note to investors today.
“This is a major upside surprise,” he said. “This opportunity could increase the eligible patient pool by up to 10 times.”
Two Copies of Gene
About 70,000 people worldwide have CF, and almost half carry two copies of that mutation. About 30 percent of patients in the treatment portion of the study saw improvement of 10 percent or more. No patients on placebo improved that much.
“People with two copies of the F508del mutation have one of the most-severe forms of cystic fibrosis,” said Chris Wright, Vertex’s senior vice president of global medicines development and medical affairs, in the statement. “In these patients, the combination of VX-809 and Kalydeco led to significant improvements in lung function that exceeded our expectations.”
Improvements in breathing were measured by how much air a patient can exhale in one second, called forced expiratory volume, or FEV-1. Kalydeco, the first medicine to target the underlying cause of CF, was approved for a mutation affecting about 4 percent of CF patients after a three-month review at the Food and Drug Administration based on studies that showed improvements on that gauge.
The company had indicated it would decide whether to progress to the next phase of studies based on a different metric, sweat chloride levels, Jason Kantor, an analyst with RBC Capital Markets, wrote in an April 26 note. Vertex said those results weren’t statistically significant for the combination therapy at this stage in the trial.
“Lung function is the single most-important marker of disease progression for people with cystic fibrosis,” said Michael P. Boyle, lead investigator of the study and director of the Johns Hopkins Adult Cystic Fibrosis Center. “Improvement in lung function is the goal of every new CF therapy.”
Cystic fibrosis is an inherited disease caused by malfunctions in the proteins that help ferry salt and water in and out of cells. The body produces a thick mucus that clogs the lungs and causes infections and damage, and most patients die before age 40. Sweat chloride is a measure of how well the proteins are functioning.
Vertex reported data from the first stage of the study in June, missing analysts’ expectations for reductions in sweat chloride after 21 days. The shares sank the most in 20 months.
“The key question is whether such a change in sweat chloride will translate into an improvement in lung function,” Phil Nadeau, an analyst with Cowen & Co., wrote in a research report at the time.
The results reported today were from about half of the patients in this portion of the study. Safety was similar in those receiving the treatment and placebo, and the trial is still going, Vertex said. Complete data, including from patients with just one copy of the F508del mutation, are expected mid-year.