Go-ahead for rival drug pushes Shire to 3-year low

Shares in Shire Pharmaceuticals slid 13 per cent yesterday after US regulators approved the launch of a rival to its best-selling drug.

Eli Lilly, one of the world's biggest drugmakers, was told late on Tuesday it can start selling Strattera, a treatment for attention deficit hyperactivity disorder, and a launch is expected early in the new year – some three months earlier than the market had been expecting.

Shire's Adderall drug for hyperactive children had sales of £200m in the first nine months of this year, and has a 29 per cent share of the $1.6bn ADHD market in the US. It accounts for 40 per cent of Shire's turnover.

Bears of the stock yesterday pointed out the clinical attractions of Strattera over Adderall: Strattera has not been classified as a controlled drug, so prescribing and dispensing it will be easier, and it is likely to be of more appeal to ADHD sufferers who do not yet get treated. Shire argues the entry of Eli Lilly, with its Big Pharma marketing muscle, will grow demand for ADHD drugs as a whole.

Shire shares were down 66p at 444p, their lowest level in three years, making them the worst performers in the FTSE 100.