Shire has been boosted by a ruling from a US court which has confirmed long-term patent coverage for its attention-deficit hyperactivity disorder drug Vyvanse in the face of a challenge from Actavis.

The US court for the District of Columbia has upheld a US Food and Drug Administration decision to grant Shire five-year new chemical entity market exclusivity for its attention-deficit hyperactivity disorder drug Vyvanse (lisdexamfetamine). The court decision means that Actavis cannot file a generic version of Vyvanse until ), which expires on February 23, 2012.

The Icelandic firm sued the FDA in February last year in a bid to overturn the NCE exclusivity on the drug, claiming that the labelling on Vyvanse states that it is a therapeutically inactive pro-drug that is metabolically converted to dextroamphetamine, eg Shire’s older ADHD treatment Adderall. Now the US court has said Actavis based its claim on “an outdated draft” of an internal FDA document “not having the force of law and superseded by formal regulation”.

The FDA approved Vyvanse in February 2007 as a new chemical entity and confirmed that decision in October last year. The court decision means that no generic versions of the drug can be submitted to the FDA until Febraury 2012, or until February 23, 2011, should a generic applicant challenge the US patents covering Vyvanse, which remain in effect until June 29, 2023.

The drug is a big earner for Shire and generated fourth-quarter sales of $145.0 million, up 41%.