On March 20, 2015, a division Bench of the Delhi High court finally gave its verdict and injuncted Glenmark from further manufacture of sitagliptin. The court permitted Glenmark to exhaust the current stock in the market.
It may be recalled that Merck had sued Glenmark for infringing their product patent on Sitagliptin (marketed as Januvia) on April 01st, 2013. Merck sought interim injunction against Glenmark seeking to restrain Glenmark from launching its Generic products Zita (generic version of Januvia) and Zita met (generic version of Janumet, combination of sitagliptin+metmorphin). The Delhi High Court however refused to grant the relief to Merck by its decision of April 5th 2013. At this time, Glenmark had already launched its product in the market.
Merck appealed against the judgement of the Single Judge and the matter was pending before the Division Bench for over a year. Glenmark’s arguments, in short was that Merck itself acknowledges that sitagliptin and sitagliptin phosphate are separate inventions as they filed for different patents for sitagliptin hydrochloride and sitagliptin and that Glenmark’s selling of the Sitagliptin phosphate salt will not infringe the ‘816 patent.
The arguement, though appealing did not find favour with the Division Bench. The DB reasons that the final efficacy of curing diabetes is derived only from sitagliptin, and Glenmark has to produce sitagliptin in order to even make any salt. Therefore, the making of sitagliptin without permission from Merck amounts to infringement. The court has also noted that Glenmark chose to launch the produc without taking steps for revocation or otherwise negotiating for a license – a launch at risk, and should be prepared for the consequences. The Court held that irreparable harm would be caused to the Plaintiff/Appellant if the injunction is not allowed. The Court further directed the Plaintiff/Appellant to undertake to compensate the Defendant/Respondent in the event it is finally held in the suit that the Defendant/Respondent is not infringing the Plaintiff/Appellant’s suit patent.
The Delhi High Court allowed the appeal filed by Merck and set aside the order of the Single Judge refusing injunction. Thus, now, Glenmark is injuncted from manufacturing and selling its drugs Zita and Zita-Met. The defendants are permitted to sell its products Zita and Zita-Met that is already in the market; however all further manufacturing activities are to be stopped.
Now, when there are compound patents, the generic industry would have to be more careful. The old-style arguement of polymorph being different from main compound may no longer hold good. One would have to raise a substantial question of patent validity, if an injunction is to be avoided.
