The post outlines Appeals filed by AstraZeneca against refusal of interim injunction in nine Patent infringement lawsuits filed at the Delhi High Court to protect their anti-diabetic drug Dapagliflozin.

The claim of AstraZeneca is based on Dapagliflozen (hereinafter referred to as ‘DAPA’) used for treatment of people suffering from type -II diabetes mellitus. DAPA it is claimed is subject matter of two Patents:

1. IN205147 (‘IN 147’) discloses Markush structure i.e. a group of compounds that covers ‘DAPA’ and is a genus Patent.   
2. No.235625 (‘IN 625’) specifically discloses DAPA and is a species Patent. The Patent is valid until 5th May 2023.

AstraZeneca, based on these 2 patents, have sued several Indian pharmaceutical companies for patent infringement, namely, 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., claiming:

1. DAPA is not identified in IN 147. The Patent in question ( 147) comprised of a basic core structure, permutations wherein could run into millions of compounds. Only 80 compounds were synthesised with each compound having the common property of inhibiting the absorption of sugar into kidneys, resulting in excess sugar being thrown out of the body through urine. Each of the 80 compounds varied considerably, and the right molecule with the best combination of the properties had not been identified in IN 147.
2. IN 625 has only one specific molecule i.e. DAPA. And it was not obvious from IN 147. If DAPA was obvious from IN 147, it would have been developed by someone else from IN 147.

In reply to the infringement action, the generic companies challenged the validity of patents and raised the following defences:

• Plaintiffs have admitted that DAPA is claimed in IN 147. There was an objection by USPTO to the application of the plaintiff’s equivalent to IN 625 in India, on the ground of prior claiming i.e. obviousness-type double patenting. The plaintiffs did not contest the said objection and on the contrary agreed to the term of patent thereunder to be coterminous with the term of the patent equivalent to IN 147. The plaintiff’s having agreed to the term of US patent equivalent of IN 625 to be the same as that of US patent equivalent of IN 147, cannot make a case contrary in India.
• The plaintiff’s, in the working statement in Form 27 filed in relation to IN’147, also furnished the working of DAPA, again admitting DAPA to have been part of IN 147.
• IN 625 was also vulnerable to challenge, as it lacked inventive step, based on what was published or publically known from IN 147;
• IN’ 625 does not set out the economic significance of the product thereof, over that of the product of IN 147

The Court, on hearing contentions of the parties, ruled against AstraZeneca, observing the following:

No Technical advancement/ Efficacy of IN ‘625 (species patent) over ‘147 (genus patent)

The Court expected IN ‘625 to describe the technical advancement and / or the difference in efficacy, from that in IN ‘147, which was not provided in IN ‘625. As the inventor of both applications, IN ‘147 and IN ‘625 is same, thus, the Court noted that said inventor, as compared to a third person, was best placed to know the inventive step i.e. technical advancement in the invention subject matter of IN 625, over that of the earlier invention subject matter of IN 147.

The Court observed that The tests of “obvious to a person skilled in the art” and “anticipation by publication” and “use before the date of filing of patent application with complete specification”, in the context of an earlier patent and its specifications, in our view, have to be different, when the inventor of both is the same”.

Court observed from the field of the invention it is clear that the subject matter of the two patents are the same. AstraZeneca has also failed to show the enhancement of the known efficacy within the meaning of Section 3(d) of the Act, between the subject matter of IN 147 and IN 625.

• DAPA being only covered and not disclosed in IN 147 and being disclosed for the first time in IN 625:

The Court held that once the appellants/AstraZeneca, in the plaints claimed the action of the respondent(s) of manufacturing medicines having DAPA as their ingredient to be an infringement of both IN 147 and IN 625, the appellants/AstraZeneca is deemed to have admitted DAPA to be the invention subject matter of both, IN 147 and IN 625. Without DAPA being disclosed in IN 147, there could be no patent concerning DAPA in IN 147 and which was being infringed by the respondent(s)/defendant(s) by manufacturing drugs/medicines with DAPA as an ingredient.

• One Invention, One Patent:

The Court noted that with respect to one invention, there could be only one Patent. Astrazennca, while claiming one invention only i.e., DAPA, are claiming two patents with respect thereto, with infringement of both, by the respondent(s)/defendant(s). The same strikes at the very root of the claim of the appellants/AstraZeneca and disentitles them from any interim relief.

• Impact of submissions made for corresponding US application:

The Court also noted an objection by the US Patent and Trademark Office (USPTO) to the application of the AstraZeneca’s equivalent to IN 625 in India, on the ground of prior claiming i.e. obviousness-type double patenting. The appellant/AstraZeneca did not contest the said objection and, on the contrary, agreed to the term of Patent thereunder to be coterminous with the term of the Patent equivalent to IN 147. 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 the validity period of the US patent equivalent to IN 147, the AstraZeneca, in India are not entitled to claim different periods of validity of the two patents.

To Sum up:

Markush claims are common in patent applications filed by the pharmaceutical companies. For species patent to get approval over the teaching/ disclosure of genus patent, it is important to show technical advancement or enhancement of the known efficacy to qualify the objection of section 3(d). Further, such efficacy will have to be viewed from the eye of a “person in the know” as compared to a “person ordinarily skilled in the art.” Further, the Patentee needs to ensure consistency in the submissions/ statements made during the prosecution of the corresponding foreign patent applications. One of the factors that went against AstraZeneca, in this case, was their statement to the USPTO agreeing to the validity period of US patent equivalent of IN 625 ending on the same day as the validity period of the US patent equivalent to IN 147.