NEW YORK (AP) -- Impax Laboratories Inc. said Friday it resolved lawsuits with Shire PLC over its generic version of Shire's attention deficit hyperactivity disorder drug Adderall XR.
Impax said Shire will pay it $48 million. Shire will continue to supply Impax with generic Adderall XR until Sept. 30, 2014, and Impax will keep paying royalties to Shire on sales of the generic. Impax said it will also continue seeking approval for its own version of the drug.
Generic versions of drugs cost less than the brand-name versions, and the price of the branded version can fall sharply after generics reach the market.
Adderall XR was one Shire's best-selling products, and as the expiration dates on its patents approached, Shire allowed Impax and Teva Pharmaceutical Industries Ltd. to market authorized generic versions. Impax and Teva were both able to make money from the generics and Shire retained more revenue from the drug than it otherwise would have.
Impax, of Hayward, Calif., began selling its version of Adderall XR in October 2009. It sued Shire for breach of contract in November 2010, saying Shire was not filling its orders. Shire countersued, and Impax said Friday that all claims from both companies will be dismissed.
Teva, which started selling its version of the drug in April 2009, also sued Shire for breach of contract. That lawsuit was settled in late 2009.
The federal government has also investigated the way Shire markets Adderall XR and a newer ADHD drug, Vyvanse. On Feb. 1 Shire agreed to pay $57.5 million to resolve the inquiry.
Vyvanse is Shire's current top seller and it is still under patent protection. In the third quarter of 2012, sales of Vyvanse climbed 24 percent to about $247 million and shares of Adderall XR fell 32 percent to $102 million.
Impax shares rose 31 cents to $20.28 in afternoon trading, and shares of Shire gained 12 cents to $100.18.