Shire pays $48m to settle generic Adderall XR claims with Impax

Shire has agreed to pay Impax $48m to settle claims it failed to fulfil orders of an authorised generic version of its big-selling drug for attention deficit hyperactivity disorder (ADHD) Adderall XR.

The settlement follows a court battle that began in November 2010, when Impax filed a suit in the US claiming that the Irish pharma company had breached a contract regarding the supply of Adderall XR (mixed amphetamine salts).

This contract was made in January 2006 as part of an earlier patent litigation settlement, with Shire agreeing that Impax should be allowed to sell Shire's authorised generic – a step it took in October 2009.

Following Impax' legal claim, Shire filed a counterclaim against Impax related to its ordering practices.

However, both suits have now been dismissed, with the two companies also updating their license and distribution agreement in addition to the settlement payment.

As part of this updated contract, which ends on September 30, 2014, Impax will continue to have the right to sell the authorised generic and will continue to pay a profit share to Shire on all sales.

Impax also said it will continue with plans to launch its own version of Adderall XR, rather than Shire's authorised generic, pending FDA approval.

This would allow the company to continue selling a version of the ADHD drug once its contract with Shire ends.

Adderall XR has been one of Shire's biggest earners, achieving revenues of $532m during 2011.

The company has sought to limit the effect of patent expiration through authorised generic versions sold by Teva and Impax, of which Shire gets a share of revenues.

However, in June last year the FDA gave approval for a generic version from Watson subsidiary Actavis, and this has already had an effect on Shire's financial performance, with sales of Adderall XR down by 32 per cent for the third quarter of 2012.