NEW YORK (AP) -- Swiss drugmaker Actavis Group said Monday it is now shipping a generic version of Shire PLC's attention deficit hyperactivity disorder drug Adderall XR.
Shire PLC, which makes the branded version of the drug, said Saturday that the FDA had approved one generic competitor. Actavis said it received approval to sell generic Adderall XR in six strengths. It said U.S. sales of Adderall XR and its generic equivalents totaled $1.99 billion over the 12 months ended March 31.
U.S shares of Shire tumbled on the news, losing $9.85, or 10.8 percent, to $81.51 in midday trading.
Impax Laboratories Inc. and Teva Pharmaceutical Industries Ltd. make authorized generic versions of Adderall XR, and Shire gets a portion of the revenue from those sales. The approval of the Actavis version means a new competitor is on the market, which will likely mean lower prices. Shire reported $532.8 million in sales of Adderall XR in 2011. It is the company's second biggest selling product after Vyvanse, a newer treatment for ADHD.
Shares of Impax lost $2.75, or 12 percent, to $20.10. Shares of Teva, which received a favorable patent ruling for its multiple sclerosis treatment Copaxone, picked up $2.20, or 5.8 percent, to $40.21.
Actavis is being acquired by Watson Pharmaceuticals Inc. of Parsippany, N.J. Watson shares gained $1.48, or 2.1 percent, to $72.50.