Pharma Giants' Tussle Over Weight Loss Medicine: Analysis Of EISAI v. Dr. Reddy's

Author:Mr Asis Panda and Anuj Maharana
Profession:NovoJuris Legal

EISAI Co. Ltd along with the patentee ("Plaintiffs") have instituted a suit for permanent injunction against Satish Reddy and others ("Defendants") for restraining the Defendants from manufacturing, selling, distributing, exporting or offering for sale any product that infringes the Plaintiff's patent no. 215528 including Lorcaserin Hydrocholride ("LH") or any other pharmaceutically acceptable salts of Lorcaserin such as Lorcaserin Hydochloride Hemihydrate ("LHH"). The Plaintiff had applied for patent in India on 23 September 2004 which was ultimately granted for a period of 20 years i.e. from 11 April 2003 till 10 April 2023. No pre-grant opposition, no post grant oppositions, no counter statements- etc., have been filed against the patent and it has been undisturbed for a period of 10 years.

Plaintiff no.1, a Japanese Pharmaceutical company which is an exclusive licensee of Indian patent no. 215528 and Plaintiff no. 2, is the patentee in respect of the above-mentioned patent. Plaintiff no. 2 claimed that it had invented a man-made molecule named Lorcaserin, around the year 2001 and has spent considerable time and resources to develop and commercialise the molecule. It is to be noted that Plaintiff no. 2 has obtained patents in over 65 jurisdictions and WHO had recognised Lorcaserin to be a new molecule. Further, the Plaintiff has carried out the mandatory requirement as per US FDA and has been granted marketing approvals in six countries. Also the Plaintiffs have already completed the regulatory approval for its drug products in India and expects pre-marketing approval by March 2019.


In August 2018, the Plaintiffs found that the Defendants were planning to commercialize Lorcaserin in Indian market. Further, online search revealed that the Defendants had filed a US patent application for LH bearing US patent application No.14/141, 112. The Plaintiffs further found that the Defendants approached the Subject Expert Committee (SEC) for permission to manufacture and market LH in India which was subsequently granted such permission in the SEC meeting of 5 August 2018. The Plaintiffs thus filed a suit for permanent injunction.

Opposition raised by the Plaintiffs:

According to the Plaintiffs, the Defendant's product LHH infringes the plaintiffs patent No.215528 which covers Lorcaserin and its pharmaceutically acceptable salts, including LHH, which are specifically claimed in Claims 38 and 39. To simplify Plaintiffs' patent is being...

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