British drugmaker Shire said today it has agreed to buy New River Pharmaceuticals for $2.6 billion or $64 a share in cash. Shire said in published reports the deal will allow the company to capture the full economic value of attention deficit hyperactivity disorder (ADHD) drug Vyvanse and to gain control of the future development and commercialization of the treatment. Shire said the acquisition is in line with its increased focus on the ADHD market. “This is an important and complementary acquisition that gives us full control of Vyvanse, a novel drug,” Shire CEO Matthew Emmens said in a statement. Emmens added that he expects the purchase to add to earnings from late 2009. New River developed Vyvanse, a follow-on ADHD drug that Shire is hoping will replace Adderall, which accounted for more than half of Shire’s third-quarter sales.In January 2005, Shire and New River struck a collaborative agreement to develop and co-promote Vyvanse.