Impax confirms patent challenge for generic Detrol

HAYWARD, Calif. — Pfizer has filed suit against generic drug maker Impax Labs in connection with the latter’s attempt to market a generic drug for bladder problems.

Impax said Friday that Pfizer filed a patent infringement suit in the U.S. District Court of the District of New Jersey in connection with Impax’s attempt to market a generic version of Detrol (tolterodine tartrate) immediate-release tablets in the 1-mg and 2-mg strengths. The drug is used to treat overactive bladder and urinary incontinence.

Impax filed a regulatory approval application with the Food and Drug Administration for the drug that contained a Paragraph IV certification, a legal assertion that patents covering Detrol are invalid, unenforceable or won’t be infringed.

Detrol had sales of about $62 million during the 12-month period ended in March, according to Wolters Kluwer Health.