The Himachal Pradesh High Court came up with key findings in deciding the interim injunction application of the Plaintiff in Boehringer Ingelheim International & Ors vs Eris Lifesciences Limited [Civil Suit (COMS) No. 09 of 2023].
Boehringer had alleged infringement of their patent rights in Indian patent number 268846 that disclosed the new chemical entity, Empagliflozin, an SGLT2 inhibitor for controlling diabetes.
While the Plaintiffs alleged infringement of the suit patent which had not been subjected to any pre-grant or post-grant opposition in India, the Defendant contented that the suit patent was vulnerable to invalidity on account of obviousness and lack of therapeutic efficacy. The Defendant referenced two prior art documents, Dapagliflozin Genus (Dapa 1) and Dapagliflozin Species (Dapa 2), to support their claim. They argued that the subject invention would be obvious to a person skilled in the art on a combined reading of the two documents because the only difference between example 12 of Dapa 1, a Markush patent, and Dapa 2 was a structural change at the same position which would motivate further substitutions to be made at said position and the suit patent too, was alleged to just have made such a structural change. The Defendant also asserted a lack of technical advance of the suit patent over the prior art. To strengthen their position regarding obviousness the Defendant relied on an expert affidavit.
The Defendant also claimed that the drug they sold was more affordable, and therefore, served public interest. Additionally, they alleged suppression of material facts by the Plaintiffs who had concealed the fact that the corresponding Chinese patent had been invalidated.
In response, the Plaintiff asserted that Empagliflozin has technical advancement over the cited documents in that it has a high selectivity for SGLT2 over SGLT1. The selectivity of Empagliflozin (>2500) is higher than the selectivity of Dapagliflozin (around 1200) of prior art Dapa 2, which in turn has a higher selectivity than the compound of Example 12 (around 900) of prior art Dapa 1. The Plaintiff also submitted an expert affidavit to support their case on obviousness.
The Court arrived at the following conclusions on the issues raised by the parties.
Obviousness
The Court held that the grounds of obviousness and lack of therapeutic efficacy taken by the Defendant were to be decided at the stage of trial. The Court noted that the specification of the suit patent already referenced Dapa 1 and Dapa 2 and held that a mere allegation that the suit patent is vulnerable is not enough and the Defendant has to prove the same.
Expert Affidavit
The Court was of the view that the veracity of the Affidavit of the expert was to be established through cross-examination at the stage of trial because the said expert affidavit was filed at the behest of the Defendant and was neither a publication nor was not in existence prior to the filing of the suit.
The Court pointed the importance of differentiating mere allegations from material evidence by stating that, “in a case of infringement under the Patents Act, at the stage of interim, the Court has to consider the factum of “credible challenge”, if any, laid by the defendant to the patent of the plaintiff or the aspect of vulnerability qua the subject patent. The Court therefore has to be careful that until and unless there is material on record, more than mere allegations, a powerfully put defence per se, in the absence of a prima facie satisfaction of the Court, cannot bound the Court to not grant the interim injunction.”.
Suppression of Invalidation of Corresponding Chinese Patent
On the issue that the Plaintiffs supressed material facts and did not approch the Court with clean hands, the Court clarified that unlike the Delhi High Court, the Himachal Pradesh High Court has no Rules governing patent suits which mandates the Plaintiff to disclose details of orders passed by any Indian or International Court or Tribunal upholding or rejecting the validity of the suit patent or corresponding patents. Regarding the duty of disclosure under Order XI, Rule 1 of the Code of Civil Procedure, the Court clarified that in patent infringement cases, the Plaintiff’s obligation is to demonstrate the existence of a registered patent being infringed by the Defendant. While concealment of facts regarding the registration of the patent in India would have been significant, non-disclosure of the invalidation of the corresponding foreign patent by the Plaintiffs did not render the suit patent vulnerable or amount to concealment. Additionally, the Court emphasised that the status of a patent, whether it is registered or invalidated, is determined independently in each country according to that country’s laws. Therefore, actions taken regarding a patent in one country don’t necessarily impact its status elsewhere. Each country’s legal framework dictates how patents are recognized and regulated within its jurisdiction.
Public Interest
On the issue of public interest, the Court held that a Defendant, being a commercial rival against whom there is an allegation of infringement of patent, cannot be allowed to raise the plea of public interest and that the Patents Act itself provides enough checks and balances to cater to public interest.
In conclusion, the Court held that the suit patent was prima facie not vulnerable to invalidity and the balance of convenience was in the favour of the Plaintiffs in view of the fact that the Plaintiffs had exclusive rights over the subject drug unlike the Defendant.
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