On May 6, 2019, Delhi High Court granted interim injunction to Eisai Co. Ltd. and Arena Pharmaceuticals (collectively called Eisai) against Dr. Reddy’s Laboratory Ltd. (DRL) in respect of their anti-obesity blockbuster drug Lorcaserin.

The suit was in respect of Eisai’s Indian patent No. 215528 covering Lorcaserin and its pharmaceutically acceptable salts including Lorcaserin Hydrochloride and Lorcaserin Hydrochloride Hemihydrate. Lorcaserin is used for treatment of obesity and sold by Eisai under the brand Belviq.

The case is particularly interesting and one of its kind where both the Defendants and the Plaintiffs did not have a product in the Indian market and the cause of action was based on the Defendants taking steps to obtain regulatory approval and their intention to launch their product in the market.

The contentions of the defendants were as follows:

  • Non-Working of patent for more than 10 years since grant and 15 years since date of patent, disentitles interim injunction.
  • Plaintiffs have admitted in IPO and EPO prosecutions for subsequent patents that lorcaserin HCl hemihydrate is not disclosed, taught, or enabled in the suit patent. Therefore, as Defendants approval relates to Lorcaserin HCl hemihydrate, therefore Defendants’ activities fall outside the scope of the patent.
  • Suit patent is invalid in light of section 3(d) of the Patents Act.

Hon’ble Mr. Justice J.R. Midha held that the plaintiffs have made out a strong prima facie case for grant of interim injunction against the defendants for the reasons given hereunder:-

  • Admissions by Defendants:

    • Mr. Girish Parhate, Director (Regulatory Affairs) of the defendants, in his statement dated January 14, 2019 admitted that their drug is covered by the plaintiffs’ suit patent.
    • The admissions made by the defendants in US patent application 2014/0187538A1 and in the pre-grant opposition filed by the defendants against the plaintiffs’ pending Indian Patent Application No. 311/KOLNP/2009 for LHH that the PCT application corresponding to the suit patent i.e. WO2003/086306 discloses Lorcaserin and hydrochloride salt of Lorcaserin and method of preparing thereof.
    • Section 3(d): The suit patent is in the nature of an originating/genus patent and the various subsequent patent applications are for improvement/selection inventions, which specifically disclose and claim a particular “species‟ of the genus patent, i.e. the hydrochloride hemihydrate form. Merely because the plaintiffs have applied for a patent separately for a specific species of the genus, it does not mean that the species patent cannot be granted or that the species patent would not fall within the coverage of the genus patent (i.e. the suit patent in the present case). Grant of a subsequent patent, which is an improvement invention, does not take the said forms out of the first/basic patent, which in the present case is the suit patent.


  • Non-working of patent: The defendants had a remedy to seek a compulsory License under Sections 83 and 84 of the Patents Act, 1970. However, the defendants, instead of applying for either a voluntary license or a compulsory license, decided to go ahead on their own volition and seek a marketing approval. The non-working of a patent particularly for a pharmaceutical product cannot have a bearing on the rights of a patentee under Section 48 of the Patents Act, 1970.


  • Balance of convenience: The Court held that the balance of convenience for the grant of interim injunction lies in favour of the plaintiffs as the defendants have evidently not “cleared the way” before going ahead with obtaining a marketing approval for launch of the infringing drug.


  • Costs: the Court held that the plaintiffs are entitled to the costs from the defendants. However, the order as to quantum of costs is deferred till the final decision of this suit. Both the parties have been directed to submit the actual cost incurred by them. The parties have been also directed to submit their estimate of future cost before the commencement of trial so that the parties shall have notice of actual cost that the other side estimate would be incurring in the course of litigation and the parties have an opportunity to take appropriate decision as to manner in which to conduct the litigation.

The matter will is now listed before the regular bench on July 4, 2019.