The US Food and Drug Administration (FDA) has stood by its decision to grant biopharmaceutical company Shire five-year New Chemical Entity (NCE) exclusivity for Vyvanse, an attention-deficit hyperactivity disorder treatment.

The FDA had previously refused to file an Abbreviated New Drug Application submitted by Actavis Elizabeth for a generic version of the treatment. The decision was contested by Actavis, which challenged the decision by suing the FDA in February 2009.

The FDA has since decided that following a thorough administrative review of governing statutory and regulatory standards and public comments, the five-year exclusivity period will stand up to the set expiry date of 23 February 2012.

The market exclusivity period was based on clinical trial data, which qualified Vyvanse as an NCE, entitling it to the five-year period.

Vyvanse is covered by US patents which will remain in effect until 29 June 2023.