Shire Pharmaceuticals’ patch product to treat attention deficit hyperactivity disorder goes under the microscope at a US Food and Drug Administration (FDA) advisory committee meeting later today, although FDA comments ahead of the event suggest it may face an uphill struggle.

In documents released on the FDA website yesterday, the agency has said that it does not believe Daytrana (methylphenidate) should be approved to treat children with ADHD in the USA because its safety has not been demonstrated adequately. The product’s efficacy is not in question, according to the document.

If the advisory committee follows the FDA’s lead, it will be the second time that Shire and Noven have been knocked back on the product. The agency issued a ‘not approvable’ notice for the product in 2003, when it was known as Methypatch, also on safety grounds. It is being developed by Shire alongside US firm Noven.

In trials, Daytrana has been associated with side effects such as decreased appetite, sleeplessness, twitching, weight loss, nausea and vomiting. FDA reviewer Robert Levin maintains that some of these side effects occurred more frequently with Daytrana than with Johnson & Johnson’s Concerta, an oral formulation of methylphenidate.

Shire and Noven re-filed for approval earlier this year with a new treatment protocol for Daytrana, in which children would wear the patch for nine rather than 12 hours, in a bid to alleviate the FDA’s concerns. The just-published documents suggest they have been unsuccessful, although there is still every chance the panel will not adopt the agency’s position.

The company is hoping that panellists will recognise the benefits of the product in treating ADHD in children who find it difficult to take oral medications.

Daytrana is one of six new products Shire is hoping to launch next year to help it weather the loss of marketing exclusivity on Adderall XR (mixed amphetamine salts), its top-selling product.

Adderall XR brought in third quarter sales of $166 million dollars, but is facing generic challenges from a number of companies. Shire has lawsuits ongoing against two generics houses - Barr and Impax - and the cases set to go to court in January and February 2006, respectively.

- Meanwhile, Shire has filed for approval to market its idursulfase drug for the treatment of Hunter syndrome with the European Medicines Agency (EMEA). The company said it is hoping for ‘approval and subsequent launch in Europe in late 2006 or early 2007’. If approved, this would be the first human enzyme replacement therapy for the treatment of Hunter syndrome, also known as mucopolysaccharidosis type II. The hereditary disease causes abnormal function of multiple organs, and in severe cases, early death.