Patent Case Summary: Astrazeneca AB & Anr. v. Intas Pharmaceuticals Ltd. & Ors. 

Astrazeneca AB & Anr. v. Intas Pharmaceuticals Ltd. & Ors.

Important issue

Whether subject matter of species patent held by Astrazeneca was disclosed in the genus patent held by the same person, thereby invalidating the species patent for lack of inventive step and being obvious to person skilled in art?


Subject matter of patent: Patent no. IN 235625 (Patent ‘625) covers the compound named Dapagliflogin (DAPA) used in treatment of Type II Diabetes Mellitus. DAPA acts as an inhibitor of Sodium dependant glucose transporter SGLT2 in the kidneys. The selective inhibition of SGLT2 normalises plasma glucose by enhancing excretion of glucose in the urine, thereby, improving insulin sensitivity and, thus, delaying the development of diabetic complications such as neuropathy, nephropathy, and retinopathy, wound healing and other related diseases. Astrazeneca also held Indian Patent No. IN 205147 (Patent ‘147) titled “C-Aryl Glucoside SGLT2 inhibitors and method” which was a Markush structure capable of producing millions of permutations and combinations.


Astrazeneca held Patent ‘147 as the genus patent, granted on 15.03.2007, with a priority date of 12.10.1999. The specie patent, Patent ‘625 was granted on 09.07.2009, bearing a priority date 20.05.2002. Patent ‘147 expired on 02.02.2020 while Patent ‘625 is valid until 15.05.2023.

The Defendant companies sought to manufacture and sell drugs containing DAPA and hence, Astrazeneca filed a suit seeking a permanent injunction from manufacturing and selling of any drugs containing the compound DAPA.

The defendants resisted the suit on the claim that the patent lacked inventive step and further, the terminal disclosure filed by Astrazeneca in the USPTO was proof of admission that DAPA was indeed covered by the genus patent held by them, in the US.


  1. Patent ‘147 contained a Markush structure with 22 variables and could yield millions of different compounds, one of which is DAPA. However, patent ‘147 discloses as many as 80 examples and DAPA was not included in them, because DAPA was not synthesized at that point of time.
  2. DAPA was first synthesized in 2001. It formed the subject matter of Patent ‘625 whose Claim 1 disclosed DAPA and its pharmaceutically accepted salts stereoisomers and produgesters. Given that the first molecule of synthesized only in 2001, it could not have been covered by Patent ‘147 whose priority date was 12.10.1999.)
  3. The derivation of DAPA from Formula 1B of Patent ‘147 is possible only in hindsight, since the Formula is capable of producing more than 1 billion different resultant compounds.
  4. To qualify as a “disclosure” under the patent law, it is important for a compound to be disclosed by a definite name, formula, etc.
  5. Defendants are wrong in arguing that once a genus patent is granted, a species patent cannot be granted. Unique features of breakthrough inventions are critical and hence, deserving of protection.
  6. In order to successfully challenge a patent on the basis of obviousness, a person with average skill and knowledge who has no inventive faculties should be able to derive at the subject matter on the basis of prior art. In  the case of DAPA the same is not possible without hindsight, and such reverse engineering is impermissible while testing for obviousness.
  7.  The terminal disclaimer filed in the USPTO as an obviation strategy and was not an admission that DAPA was disclosed in the genus patent.


  1. Defendants pointed out that Plaintiffs have presented mutually destructive claims. They claim infringement of both patents, ‘147 as well as ‘625 by the manufacturing of DAPA and yet claim that DAPA was not disclosed by ‘147 and hence, did not form its protected subject matter.
  2. DAPA was covered by the Markush structure claimed in Patent ‘147 and it expired on 02.02.2020, thereby making the subject matter accessible in public domain. On the other hand, Patent ‘625 remains vvulnerable to revocation for lack on inventive step.
  3. As per Section 2 (1)(ja), inventive step requires assessment of two aspects- technical advancement or economic significance and not obvious to person skilled in art.
  4. The plaintiff was under an obligation as per Section 8 of the Act to disclose the status of any application made in foreign IP offices regarding the same subject matter. This means that they should have kept the Indian office abreast with the developments of the US equivalent of Patent ‘625. In the US, an objection regarding obviousness was raised by the USPTO, and to resolve the same, the plaintiffs filed a terminal disclosure wherein they agreed that both patents would end on the same date. The Defendants contested that this was an admission by the Plaintiff that DAPA was covered in the genus patent. In any case, the objection raised by the USPTO and its resolution by way of a terminal disclaimer should have been informed to the Indian Patent Office. This non-compliance with a mandatory requirement under Section 8 of the ACt makes the patent further vulnerable under Section 64 (1)(m) of the Act.
  5. Speaking of legislative intent the Defendants pointed out that in 2002 Section 53(4)
    was added which made clear that monopoly of rights by patent holders should be regulated . This would mean that patent protection should not be extended to selected compounds of a pre-existing Markush structure without strict scrutiny.


  • At the stage of preliminary injunction it is not necessary for the Defendants to conclusively prove invalidity of patent, establishment of a prima facie case is sufficient.
  • The fact that the infringement suit was filed with regard to both patents is sufficient clue at this stage that DAPA is under both patents.
  • On a comparison of relevant extracts from both patents ‘147 and ‘625  there emerges no substantial technical advancement or economic significance that would make the synthesis of DAPA an “inventive step” under Section 2(1)(ja)
  • The terminal disclaimer filed by the Plaintiffs in USPTO, even if not a complete bar operates as estoppel by conduct. The non-compliance with Section 8 was wrong and it makes Patent ‘625 vulnerable to revocation.
  • Therefore, injunction prayed for by Astrazeneca is refused.


Citation 2020 SCC Online Del 1446

Copy of judgement

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