Shire's Search for Tranquility

Matthew Emmens, Shire's chief executive, said he believes the drug, Daytrana, could be launched by mid-year. The FDA asked questions about labeling, data clarification and post-marketing surveillance. Shire has responded to the FDA's requests.

In January, Shire's other partner, New River Pharmaceuticals (NRPH Quote), said the FDA had begun reviewing NRP104, which Emmens said has a better safety profile than Adderall XR and Adderall. The drug would treat children ages six to 12.

Emmens told analysts and investors Thursday that he couldn't predict how the FDA would act on strengthening labels of existing ADHD drugs or how the agency's action might affect its experimental ADHD compounds.

Adderall XR and Adderall already carry a "black box" warning -- the most emphatic FDA alert -- about amphetamines having a high potential for abuse. The warning says amphetamine misuse "may cause sudden death and serious cardiovascular adverse events."

Earlier this month, an FDA advisory committee voted 8-7, with one abstention, to recommend a black box warning for all ADHD stimulant drugs. The vote triggered a debate among experts who said there was no correlation between these drugs and the dangerous side effects vs. those who said it would be better to add the warning now and remove it later if subsequent tests showed no link.

"We believe the label adequately warns physicians," Emmens said. He repeated comments, initially made after the FDA advisory panel meeting, that physicians and patients would be better served if regulators first determined if there's a link to any side effects before requiring a black box. The company has said it would be "unprecedented" for the FDA to impose a black box warning "that has not been supported by sufficient data."

Another FDA advisory committee is scheduled to meet March 22 to discuss ADHD drugs' effect on children. The agency isn't bound by the recommendations of its advisory panels, but it tends to follow them.