Dec 19 (Reuters) - Vertex Pharmaceuticals Inc said on Thursday that ivacaftor, an experimental drug to treat cystic fibrosis, failed to meet its targeted treatment goal in a late-stage study in people aged 6 and older with the "R117H" gene mutation.
Shares fell to $64.20 in pre-market trading, a decline of 6.4 percent from a close of $68.63.
Vertex said that a subset of patients, those 18 years and older, showed statistically significant improvement in lung function and other secondary measures. The total study included 69 people and 50 of them were 18 or older.
The company said it will meet with the U.S. Food and Drug Administration early in 2014 to discuss submitting the drug for that group of people with the gene mutation.
The R117H mutation can result in varying degrees of cystic fibrosis depending on what other gene mutations are present.
Vertex said it has submitted the drug for approval for use in people with some other mutations and has two other studies underway.
(Reporting by Caroline Humer; Editing by Gerald E. McCormick)