Sitagliptin Judgement: An Overview

In a recent, very intensely contested litigation between Merck Sharp and Glenmark Pharmaceuticals Ltd., the Hon'ble Delhi High Court delivered a much awaited judgement. In the suit Merck contended infringement of its Anti-diabetic drug Sitagliptin [protected by Indian Patent No. 209816 (IN'816); marketed under trade names - Januvia and Janumet or (Istavel or Istamet of Merck's Licensee-Sun Pharma] by Glenmark. Whereas Glenmark contended that its product on Sitagliptin, which is Sitagliptin phosphate monohydrate (marketed under trade names Zita and Zitamet) did not infringe Merck's patent IN'816 considering the said patent only covered the basic free form Sitagliptin i.e. Sitagliptin hydrochloride and not Sitagliptin phosphate monohydrate. Glenmark also contended that Merck had abandoned its Indian Application No. 5948/DELNP/2005 pertaining to Sitagliptin Phosphate Monohydrate which attributed to the fact that both molecules namely Sitagliptin Phosphate monohydrate and