Generics The Court of Appeals for the Federal Circuit ruled in favor of Merck & Co in a patent challenge brought by Mylan Pharmaceuticals (now Viatris) related to sitagliptin dihydrogen phosphate, an active ingredient in Januvia (sitagliptin), Janumet (sitagliptin and metformin hydrochloride) and Janumet XR (sitagliptin and metformin hydrochloride extended-release). 30 September 2022