Shire reported that FDA had also responded to its citizen petition concerning the fact that Adderall XR is a complex controlled-release product. FDA response stated that all ANDAs have to establish bioequivalence using partial area under the curve measurements at five hours and beyond five hours for both d- and l- amphetamine. FDA response is consistent with its recent decisions on other long-acting ADHD products, the company noted. FDA has not approved any other ANDAs for generic versions of Adderall XR.

The decision came somewhat as a surprise to Shire, as although approval of a rival generic version had been expected, analysts had predicted that this would only happen in 2013 at the earliest, according to Financial Times.

Although there are already two generics of Adderall XR on the market these are authorised generics, produced under license by Israel’s Teva Pharmaceuticals (Teva) and US-based Impax Laboratories (Impax).

Shire, which is UK’s third-largest pharmaceutical company, said that ‘it believes that it will remain competitive in the Adderall XR marketplace through the distribution of branded Adderall XR and through its two authorised generic partners, Teva and Impax.’ Despite the setback, and although the company recognises that there will be multiple dynamics affecting the overall market following the approval of the Actavis’s generic version, Shire added that it ‘continues to believe that it will deliver good, full year 2012 earnings growth.’

Despite its confidence, Shire has much to lose, especially if Actavis prices its generic version at a much lower price than the authorised generics from Teva and Impax. Adderall XR, and its generics equivalents, had US sales of approximately US$1.99 billion for the 12 months ending 31 March 2012, according to IMS Health.

In a press statement Actavis said that the approval of their generic version of Adderall XR ‘offers a significant value to our customers and patients. With ADHD class medications experiencing shortages in 2012, this important product will offer value and supply to the marketplace.’

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