Shire has been boosted by news that the US Food and Drug Administration has expanded the label on its attention-deficit hyperactivity disorder drug Intuniv.

The agency has now approved the use of once-daily Intuniv (guanfacine) extended-release tablets as adjunctive therapy to stimulants for ADHD sufferers aged six to 17 as part of a total treatment programme. The FDA's decision means that the drug is the only once-daily ADHD medication approved for administration as adjunctive therapy to stimulants, thus offering doctors a new treatment option.

Michael Yasick, head of Shire's ADHD business unit, said the approval "marks a significant development in our ADHD portfolio -- one that may help to address symptoms that many children...may experience while on stimulant treatment". For 2010, its first full year on the market, Intuniv sales reached $166 million.

Shire also announced that it has submitted a complete response to the not approvable letter issued by the FDA in April 2008 for the hereditary angioedema (HAE) drug Firazyr (icatibant).

The drug is already approved for the treatment of acute HAE attacks in 37 countries, including those within the European Union, but to satisfy the US agency's demands for more data, Shire conducted an additional Phase III study, the results from which (published in December) were positive.