NEW YORK (AP) – Impax Laboratories Inc. said May 6 it received a second patent lawsuit from Johnson & Johnson’s Alza Corp. division related to Impax’s proposed generic version of drug Concerta, which treats the attention deficit hyperactivity disorder.

Impax said the lawsuit alleges its generic violates patents belonging to Alza supporting Concerta tablets of 18 milligrams, 27 milligrams and 36 milligrams.

In November, another J&J unit – Ortho-McNeil-Janssen Pharmaceutical – sued Impax over a generic version of 54-milligram Concerta tablets.

Impax, based in Hayward, Calif., said U.S. sales of Concerta totaled $1.4 billion in the 12 months ended Feb. 28.

On Monday, Watson Pharmaceuticals Inc. started selling an authorized generic version of Concerta. Ortho-McNeil-Janssen Pharmaceutical is making and supplying the drug to Watson. Watson is marketing the drug and pays Ortho-McNeil-Janssen a share of the revenue from sales. The agreement lasts until 2014.

Impax’s generic has not been approved by the Food and Drug Administration. Teva Pharmaceutical Industries Ltd. will market Impax’s drug once the product is approved.

Source: The Associated Press