Dapagliflozin patent case: Where is the unity?

Unity of invention is one of the criteria in patent which means only one patent is allowed for one invention or patent should claim one invention only. In US and Europe, the term “Double patenting” is used and have clause in their patent laws which do not allow more than one patent on same invention. Recent matter of Dapaglifozin patent case in India, also roll around this.?

Plaintiff:?AstraZeneca AB and AstraZeneca Pharma India Limited

Defendant:?Intas Pharmaceuticals Ltd., Alkem Laboratories Ltd., Torrent Pharmaceuticals Ltd, Micro Labs Limited, Zydus Healthcare Ltd., Eris Lifesciences Ltd., USV Pvt. Ltd., MSN Laboratories Pvt. Ltd., Ajanta Pharma Ltd (collectively, the Defendants).

Introduction

Dapagliflozin is marketed as Farxiga, which is an SGLT2 inhibitor which is useful in treatment of Type -2 Diabetes mellitus. The said drug is being administered in order to prevent the kidney from reabsorbing glucose, so that it normalizes plasma glucose by enhancing excretion of glucose in urine and, thereby improving insulin sensitivity. The case primarily questions two patents of Dapagliflozin (DAPA) drug used in diabetes.

1) Indian Patent No. 205147

2) Indian Patent No. 235625

The registered patent holder of these two patents was Bristol Myers Squibb Company (“Bristol”). Bristol, via an assignment deed dated 01.02.2014, allotted the rights within the aforesaid patents in favour of Astra Sweden. Astra has obtained the required statutory approvals for commercialization and selling DAPA in India. IN 147 was the genus patent that expired in 2020 and IN 625 is its species, which is going to expire in 2023.

What was the issue?

• Whether both the patents discloses Dapagliflozin [“DAPA”]?
• Whether IN 625 is considered as invalid for lack of inventive step and being obvious to a person skilled in art as it was previously disclosed in genus patent IN 147.

Plaintiff’s Claim:

The plaintiffs argued that?IN 147 is the genus patent and IN 625 is the species patent. IN147 is a Markush structure with 22 variables and group of compounds, in millions of variations and combinations one of which is DAPA. The plaintiffs also pointed out that DAPA is not obvious from IN 147 because IN 147 has a million possibilities. They also argued that in IN625, there is great commercial success, a number of attempts by various third parties to infringe the said mark, resulting in several injunctions granted by the court. They also argued that the IPO examined the patent for 7 years before actually granting it, and it operated for 15+ years without any opposition. The Plaintiffs also stated that the in United States of America (USA/US) also, there was no publication of the patent corresponding to IN 147 prior to the filing of the patent corresponding to IN 625.

Defendant’s Claim:

The Defendants in return claimed that a single compound cannot be protected by two different patents and the Patent 1 is already expired in 2020 hence monopoly of Plaintiff is over.?They also claimed that Patent 2 is anticipated by several publications of patent 1 hence it is an obvious attempt of double patenting. They also claimed that there was a declaration by the plaintiffs before the USPTO as well as before the Courts in USA in the proceedings against Zydus Pharmaceuticals USA, that the DAPA was covered in US patents corresponding to both, IN 147 and IN 625. Further, to overcome the objection the plaintiff agreed that the validity period of US patent corresponding to IN 625 would end on the same day on which the validity period of US patent corresponding to IN 147 would end. Further, in the working statement in Form 27 filed in relation to IN 147, also furnished the working of DAPA, again reveals admitting DAPA is a part of IN 147.

Judgement:

The court found out the fact that the plaintiffs have taken out an infringement action for both IN 147 and IN 625 is an enough clue that DAPA is alleged in each suit patents. The Court opined that once the AstraZeneca, before the USPTO applied for and agreed to the validity period of US patent equivalent of IN 625 ending on the same day as IN 147, the AstraZeneca, in India are not entitled to claim different periods of validity of the two patents.

Court observed that, there is no enhancement of the known efficacy, within the meaning of Section 3(d) of the Act, between the product subject matter of IN 147 and IN 625. The Court noted that with respect to one invention, there could be only one Patent. AstraZeneca, while claiming one invention only i.e., DAPA, are claiming two patents, with infringement of both, by the defendant(s). This attacks root of the claim of the appellants/AstraZeneca and excludes them from any interim relief. Further, as per the judgement, the court said “no merit in the appeals, which are dismissed, with costs assessed at Rs.5, 00, 000/- to the defendant(s) in each of the suits”. The overall fine will be Rs 45 lakh.

Conclusion

The Supreme Court on Tuesday, Jul 19, 2022, rejected AstraZeneca’s appeal seeking to prevent Indian generic drug makers from manufacturing and selling low-cost versions of its diabetes medicine, Dapagliflozin (DAPA). It asked the Delhi High Court to proceed with the matter and decide on the appeal expeditiously.

By: Karuna Mahajan & Sanjaykumar Patel (Excelon IP)