FMC Corporation & ANR. v. Natco Pharma Limited

Patent infringement Case study

Case Details

Case name- FMC Corporation & Anr. v. Natco Pharma Limited

Decided on- 7 July 2021

Citation-2021 SCC OnLine Del 3647

Court Name- Delhi High Court

Quorum- Justice C. Hari Shankar



1.    Patents IN’307 (product patent), IN’ 978 (genus patent) and IN’ 332 (process patent) were owned by the plaintiff. The main dispute was with regard Chlorantraniliprole or “CTPR” and its preparation process thereof.


2.    IN’307 is a subsisting patent and no pre grant or post grant opposition (Section 25 of the Patents Act, 1970) was filed by anyone (including the Defendant). The patent has been granted in more than 40 countries. No opposition was filed against IN’332 as well. CTPR is registered with “the Central Insecticide Board” under Section 9(3) of the Insecticides Act of 1968.


3.  The plaintiff holds exclusive rights over CTPR, he can market, manufacture or sell and distribute CTPR in India. No 3rd party can do the same without a valid license.


4.  In October 2019 a dispute arose when CTPR was launched by the Defendant in the form of an insecticide base and further filed an application for “improved preparation” of CTPR with the Indian Patent Office. (improved preparation of anthranilimide derivatives).


5.   The Plaintiff found the Defendant’s act infringing upon his ongoing patents and filed for permanent injunction against the same. Plaintiff also filed for an interlocutory injunction while the case was “sub judice”.


6.    On the other hand, the Defendant raised an argument that the patents were invalid in his response to the applications made by the plaintiff. Further, Defendant also argued that the plaintiff’s products must revoked as the “novel compound”. He further stated that in the patent IN’307, there already exists evidence of the compound in the teachings of “Markush claims in IN’978”.

Relief Sought by the Plaintiff- permanent injunction to stop the infringing acts by the defendant against IN’307 and IN’332.

 Issue raised

“Whether Patent IN’307 was liable to revoked as the product doesn’t fulfil the criteria of non-obviousness as evident from the genus patent IN’978?”


Section 107 of the Patents Act, 1970- deals with Defences in a patent infringement suit. Section 107(1) states that every ground on which a plaintiff’s suit patent might be revoked under Section 64 of the Act must be a defence in a patent infringement suit.


Section 64 of the Patents Act, 1970- This section provides for the grounds on which a patent may be revoked.


Section 10(4) of the Patents Act, 1970- stipulates the scope of complete specification.


Submissions on behalf of the Plaintiff

  • The Defendant has to prove a prima facie case against the validity of the suit patent in the interlocutory stage. The defendant didn’t establish a prima facie case and they haven’t even placed an expert opinion on record to prove the “vulnerability” of the subsisting patents.
  • As a result of the noncompliance the Defendant has failed to carry the burden of proof statutorily placed on them.
  • The Markush structure covers millions of compounds and even though it is not false that CTPR (under the IN’978 claim) is one of the compounds under the Markush structure, even a person skilled in the art cannot synthesize the same without any imagination and creativity invested in the process. [Markush claims defined under Astrazeneca AB v. Intas Pharmaceuticals[1]]

Furthermore, the Plaintiff argued that the whole concept of “genus and species” patents as envisaged under Section 10(5) of the Patents Act, 1970 would not exist. Thus, it is absurd that something like that becomes a claim covered under a Markush structure could negate patentability of the existing individual compounds therein.

Defendant’s Stance

The entire case is based in Section 107 (1)- Section 107(1) states that every ground on which a plaintiff’s suit patent might be revoked under Section 64 of the Act must be a defence in a patent infringement suit.

The defendant based his argument on this point stating that the patent in question itself is invalid and is liable to be revoked.

The second argument placed was that “grant of a patent does not necessarily raise a presumption of validity”. Since the existing patent product is an exact reflection of the teachings of the genus patent ‘978; IN‘307 is thus, liable to be revoked. The counsel on behalf of the defendant tried to portray that the present suit patent is vulnerable to succeed by raising this point. The Strix v. Maharaja Appliances referred to, the court here delineates the “standard of credibility” of the challenge that the defendant needs to pose to the validity of the patent suit.[2]

The defendant further stated that the Plaintiff has only admitted that CTPR is covered under IN‘978. This furnished a further point by placing reliance on the Novartis judgement observed by the Apex Court of India.[3]

This case held that “there is no difference between disclosure and coverage”. Thus, the defendant concluded this point by stating that “acknowledgement of coverage amounts to an acknowledgement of disclosure”.

The Complete specification of claim 22 in ‘978 when it is applied to Markush led to CTPR.

Court’s Verdict


  • The court stated that there is a certain etymological difference existing between the terms “presumption” and “guarantee” of validity. The Apex Court has stated in its precedents that the grant of a patent doesn’t guarantee its validity which means that a once a patent is granted, it does not automatically become immune to challenge in the future.
  • In the interlocutory stage, it is imperative to place on record a substantial material evidence or any kind of expert opinion. The court recognised that a “credible challenge” to the validity of the patent would be sufficient. It is not necessary to place expert opinions as well. However, a material evidence must be placed.
  • The Court came up with a logical view while countering the Defendant’s technical arguments regarding the Synthesis of CTPR. The Court stated that CTPR syntnesis from the “Markush claims” is only possible because the Defendant cherry-picked substitutions/ structures. In fact on a careful perusal of IN‘978, the court concluded that it doesn’t discern any teachings of CTPR. Thus the plaintiff’s patents fulfil the non-obviousness criteria for validity of patent.     

Finally the Delhi High Court granted the interlocutory injunction.


This case explored the standard of credibility required to prove the vulnerability of the suit patent and also showed that why the Defendant lost it to the plaintiff. Even though the Court recognised that at the interlocutory stage there is no need to furnish expert opinion and only a reasonable doubt must be introduced to challenge the validity of the patent, a substantial material must be quoted to support this claim. This is where the defendant actually weakened their case. They couldn’t fulfil their burden of proof. If we take a look at the technical argument the Court brilliantly manoeuvred itself around the confusion created by the Defendant using the Markush claims. Finally the Defendant was restrained from manufacturing selling distributing etc. (exercising exclusive rights that come with the plaintiff’s patent). The Defendants cannot even use the processes needed to manufacture Chlorantraniliprole.

When we peruse the judgement given, it is simple and it has discussed the details of the patents involved in a detailed manner thus leaving no room for any confusion, which is something that shall be appreciated.

[1] Astrazeneca AB v. Intas Pharmaceuticals, 2020 (84) PTC 326 (Del)

[2] Strix v. Maharaja Appliances, 2009 SCC OnLine Del 2825

[3] Novartis AG v. U.O.I, (2013) 6 SCC 1