FDA staff says ADHD skin patch not safe enough

WASHINGTON (Reuters) – An experimental skin patch to treat attention deficit hyperactivity disorder in some children should not be approved in the United States because of safety risks, U.S. regulatory staff said on Thursday.

Two new studies for the patch, which is made by Britain’s Shire Pharmaceuticals Group Plc and U.S. Noven Pharmaceuticals Inc., did not prove it was safe enough, Food and Drug Administration reviewers said in memos posted on the Internet. Shares of both Noven and Shire tumbled on the news.

The review was released ahead of an FDA meeting on Friday, when the agency plans to seek advice from a panel of advisers over whether to approve the patch. The FDA usually follows their advice.

The patch, called the methylphenidate transdermal system, or MTS, aims to deliver via the skin a generic version of one of the most popular ADHD treatments — Swiss drug maker Novartis AG’s Ritalin.

FDA officials in April 2003 rejected the patch over concerns about high rates of insomnia, anorexia, and weight loss when used for 12 hours. Since then, Noven conducted additional studies that it has said showed MTS was safe and effective.

FDA reviewers on Thursday said the patch, designed for once-daily use in children aged 6 to 12 years, still caused the side effects at levels too high to be acceptable. MTS was also linked to a relatively high risk of developing a tic disorder, they wrote. "The safety and tolerability profile of MTS treatment in these two new studies does not appear to be significantly more acceptable than that in the previous MTS submission," the memo said. "Generally, it appears that the identical safety concerns remain."