Watson confirms patent challenge over generic Exalgo

MORRISTOWN, N.J. — Drug maker Watson Pharmaceuticals said it has filed a regulatory approval application for a generic painkiller, challenging the patent that covers the branded version.

Watson announced Tuesday that it had filed an application with the Food and Drug Administration seeking approval for hydromorphone hydrochloride extended-release tablets in the 8-mg, 12-mg and 16-mg strengths. The drug is a generic version of Mallinckrodt’s Exalgo.

Pursuant to the Hatch-Waxman Act of 1984, which created the approval pathway for generic pharmaceutical drugs, Mallinckrodt filed a patent infringement suit against Watson last week. The suit puts a stay on final approval of Watson’s version of the drug until April 2013, or until the two companies reach a settlement. The patents covering the drug expire in July 2014, according to the FDA.