S. Ravindra bhat, J.

1. The appellant – Merck Sharp & Dohme (hereafter “MSD”) – is aggrieved by the dismissal of its application for an ad interim injunction restraining the respondent/defendant Glenmark Pharmaceuticals (hereafter “Glenmark”) from using its patented product Sitagliptin (Indian Patent No. 209816, hereafter “the patent” or “the suit patent”). MSD, in its suit, claimed permanent injunction restraining infringement of the patent, damages, rendition of accounts and delivery up. The suit patent concerns a drug which lowers blood sugar levels in Type 2 Diabetes Mellitus ("T2DM") patients. Glenmark was on caveat: the learned Single Judge heard the parties at the first hearing. Glenmark opposed the application for ad interim injunction and relied on documents produced during the hearing. The learned Single Judge rejected the injunction application.

MSD’s Contentions - Pleadings and Submissions

2. MSD, a New Jersey incorporated company, imports and sells the drugs in question, after local packaging, under the trademarks “Januvia” and “Janumet”, in India. In addition, MSD also works its invention through Sun Pharmaceutical Industries Ltd, the second plaintiff, its marketing and distributing licensee for the drugs in question in this suit, which are sold under the trademarks “Istavel” and “Istamet”. MSD claims that it holds the patent – IN 209816 (hereafter referred to as “the suit patent”) – which covers the said drugs. Glenmark is another multinational pharmaceutical company. It launched its products under the trademarks “Zita” and “Zitamet”. Both Glenmark’s and MSD’s products seek to treat T2DM.

3. MSD alleges that Glenmark’s products infringe its patent. MSD also claims that it has been granted patents in 102 countries for the suit patent formulation i.e. the Sitagliptin molecule. The Indian Patent application was filed on 06.01.2004; the international application being PCT/US2002/021349 filed on 05.07.2002 with the priority date 06.07.2001. The suit patent was finally granted on 06.09.2007, bearing the title “Beta- Aminotetra Hydroimidazo - (1, 2-A) Pyrazines And Tetrahydrotrioazolo (4, 3-A) Pyrazines As Dipeptidyl Peptidase Inhibitors For The Treatment Or Prevention Of Diabetes”. It is claimed that the application for the said patent was not opposed either in pre-grant or post-grant proceedings by anyone, including Glenmark, despite extensive publicity for the commercial product sold in India under the brand names ‘Januvia’ and ‘Janumet’. The Sitagliptin phosphate monohydrate salt is sold under the trademarks Januvia, by MSD and Istavel, by its licensee. Likewise, the combination of Metformin and Sitagliptin (in its diphosphate monohydrate salt) is sold under the trademark Janumet, by MSD and Instamet, by its licensee.

4. According to MSD, Sitagliptin is the active pharmaceutical ingredient in the said drugs, which was approved for sale in the United States of America in October 2006 and in the Indian market on 23.08.2008. The suit patent has 20 claims of which Sitagliptin is covered in 13 claims. Sitagliptin and its pharmaceutically acceptable salts are specifically claimed by Claim No.19 of the suit patent. Claim No.1 embraces all forms of Sitagliptin, all Stereoisomers [Two molecules are described as stereoisomers of each other if they are made of the same atoms, connected in the same sequence, but the atoms are positioned differently in space. The difference between two stereoisomers can only be seen when the three dimensional arrangement of the molecules is considered. Stereoisomers are a type of isomer (i.e different substances that have the same formula). Ref. http://www.chemicool.com/definition/stereoisomers.html.], including R Stereoisomers in the commercial product, all salts and solvates of Sitagliptin and the Sitagliptin molecule (i.e. the free amine). The plaintiff has outlined the technical details pertaining to Sitagliptin and emphasized that the commercial product comprises the R- stereois