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  • Abhishek Goyal

Process Patent Infringement: Glenmark v. Symed


Highlighting the significance of Section 104 A of the Patents Act, 1970 (‘Act’) in case of process patent, the Division bench of the High Court of Delhi vacated the earlier order of interim injunction granted in favour of Symed for the infringement of their process patent of manufacture of Linezoid, a drug used to treat infection caused by gram positive bacteria.


The entire genesis of the case dates back to the period when Symed Labs filed a suit against Glenmark alleging infringing of its patents: 213062 & 213063. The ‘062’ patent was granted for “Novel Intermediates for linezolid and related compounds” while the 063 ‘patent’ was granted for “A novel process for the preparation of linezolid and related compounds”. In this suit, Symed moved an application under Order XXXIX Rules 1 and 2 of the Civil Procedure Code, seeking an ad interim injunction restraining the Defendant therein (Glenmark) from manufacturing, selling, offering for sale, advertising or directly or indirectly dealing in the product Linezolid manufactured in a manner so as to result in infringement of its registered patents.


Before the single judge, Symed argued that both its patents were directed towards a more economical, safe and commercially viable process of manufacture of Linezoid as advancement over the process disclosed in the prior arts. It was also urged by them that "N - [3 - Chloro - 2 - (R) - hydroxprophy1] - 3 - fluoro - 4 - morpholinyl - anlaniline" (CHFA) (claimed in Claims 18 and 19 of IN 063) and "N - 3 [Phthalimido - 2 - (R) - hydroxprophyl] - 3 – fluoro - 4 (morpholinyl) aniline" (PHPFMA) (claimed in Claims 23, 24 and25 of IN 062) are exclusively formed/ generated and used in the processes for the production of Linezolid as claimed in the suit patents, therefore, the presence of any of these intermediate compounds in the final product would be indicative of the fact that the process has been manufactured by the patented process. Symed, further, argued on the basis of the sample test conducted, both, before and after the filing of the suit on Linezoid manufactured by Glenmark (marketed as ‘Lizolid’) that the presence of CHFA, PHPFMA and Zodiac-4 indicated that Glenmark was infringing its patent. On the contrary, Glenmark challenged the validity of Symed’s patent besides contending that pre-suits reports did not indicate presence of CHFA in Lizolid, which was shown to exist in the post suit reports. Glenmark also stressed that the presence of Zodiac-4 and PHPFMA in the final product prepared by was not indicative of infringement as said intermediate product could also be found in the final product produced by processes of manufacture of Linezolid already known in the art.


The Hon’ble Single judge considered the arguments of both the sides and observed that this case does not relate to infringement of any product, rather, it relates to the infringement of the patent processes. According to the Hon’ble court the presence of CHFA, PHPFMA and Zodiac-4 was a strong indicator of the fact that the Symed’s patented processes were used because Glenmark has not come forward explaining the process that they used to obtain Linezolid API. The Single Judge also dismissed the argument or lack of CHFA in pre suit reports and its presence in post suit reports by observing that this was possible due to the fact that the samples were not tested for CHFA and based on these observations, an ad interim injunction was granted against Glenmark.


Subsequently, Glenmark filed an appeal against this order and relying on Section 104 A(1)(b) of the Act, argued that the onus was on the plaintiff/respondent to prove that the product of the defendants/appellants was identical to the product of the plaintiff/respondent. It was also argued that Linezolid API manufactured by them is not identical to the Linezolid API manufactured by the respondent/plaintiff.

The Division bench, agreed with this submission of Glenmark and while vacating the order of temporary injunction observed that before the learned Single Judge could grant an injunction in favour of the respondent/plaintiff, it was incumbent upon him to, prima facie, come to a conclusion that the Linezolid API manufactured by the plaintiff using its patented processes was identical to the Linezolid API manufactured by the defendants/appellants, which does not appears to have been done. The court also observed that though there was a reference to the said provision in recording the submission of the learned counsel for the defendants/appellants, there was no discussion as to the applicability of that provision. Furthermore, there is no finding rendered prima facie or otherwise that the two products are identical.

The bench also upheld the argument made by Glenmark the Linezolid API manufactured by it, all the three markers, namely, CHFA, PHPFMA and ZODIAC-4 were present whereas the process IN 213062 and IN 213063 would only result in Linezolid API with two of the markers in each case, namely, CHFA and ZODIAC-4 in the case of IN 213063 and CHFA and PHPFMA in the case of IN 213062 respectively. Thus, the division bench also observed that the Glenmark’s product would indicate that the process used was different.


It was subsequently agreed between the parties, in terms of the expert report of Prof. Steven W. Baldwin, that Glenmark would use the Glenmark process, which is virtually identical to the Upjohn process as indicated in the said report and both these process being different from the process of preparation of linezolid, which is employed by the Symed. In terms of such interim agreement, the appeal was finally disposed of.


This case is the first of its kind, which actually demonstrates the difficulties, and uncertainties that arise in establishing that the products are identical. This case also highlights how the process patent suits are to be dealt with and on whom the initial burden to prove a case rests.

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