Sanofi sued Merck Sharp & Dohme Corp. alleging that the Merck & Co. Inc. unit infringed on two patents for its insulin product Lantus.

The suit, filed in the U.S. District Court for the District of New Jersey, was triggered by notification from Merck in June that it had filed a new drug application with the U.S. Food and Drug Administration for an insulin glargine vial drug product.

Merck's application included a certification challenging all Sanofi patents listed in the FDA orange book for Lantus and Lantus SoloStar products.