Regulators have ruled against Shire in a battle over generic copies of its hyperactivity drug Adderall XR, approving a cut-price version of the medicine from Actavis, which is being bought by Watson Pharmaceuticals. The decision is a blow to Shire's near-term earnings and shares in the London-listed drugmaker tumbled 12 percent to 17.30 pounds by 5:40 a.m. EDT (0940 GMT). Until now there have only been two authorized generic forms of Adderall XR, both supplied by Shire, and the arrival of the new competitor from Actavis, despite an appeal against the move by Shire, will increase pricing pressure.
