NEW YORK (AP) -- The Food and Drug Administration said Tuesday it sent a warning letter to Cornerstone Therapeutics Inc. alleging that Cornerstone's promotional materials withheld information about the risks of its asthma drug Zyflo CR.
The FDA said the materials violated the Food, Drug, and Cosmetic Act. Some of the materials used outdated labeling and suggested Zyflo CR is more effective than competing drugs like Singulair, according to the FDA's letter. The FDA contacted Cornerstone on June 22 and the company's website appears to contain updated information about the drug.
According to the FDA, a Cornerstone web page about Zyflo CR presented claims about the drug's effectiveness, but left out information about its risks, which can include liver toxicity and neuropsychiatric events like sleep disorders and behavioral changes. The page also left out information stating that Zyflo CR is not recommended for people with liver disease, or who have allergic reaction to ingredients.
The agency also said a Cornerstone visual aid did not include warnings about the most serious side effects or the most common ones. While the aid included some information about the drug's risks, that information was printed on the back of the visual aid. But the item had an adhesive strip on the back, so the information would not have remained visible.
The visual aid suggested that Zyflo CR works better than drugs like Singulair and Accolate -- called leukotriene receptor antagonists, or LTRAs -- but the FDA is not aware of clinical evidence that Zyflo CR works better than those drugs. It also used outdated labeling for Zyflo CR. It used labeling that was approved in May 2007 instead of wording that was approved in August 2009.
The labeling says Zyflo CR should be used early in the treatment of chronic asthma, but left out a recommendation from the National Heart, Lung, and Blood Institute that said Zyflo CR is "less desirable than LTRAs due to more limited efficacy data and the need for liver function monitoring."
Zyflo is approved as a chronic asthma treatment for adults and for children older than 12. It is not approved for use against acute asthma attacks.
The FDA reported the violations in a letter addressed to Cornerstone Chief Medical Office Brian Dickson. The agency said it last accessed the web page on April 29. Cornerstone did not immediately respond to requests for comment.
In afternoon trading, shares of Cary, N.C.-based Cornerstone slipped 2 cents to $5.58.