Walking on a Known Path...!

Dapagliflozin - Summary of the Judgement today of DHC

As we all are aware, AstraZeneca has dragged very many Indian generic pharma companies to Delhi High Court to prevent them from manufacturing and selling generic versions of its diabetic medicine Dapagliflozin. 

The court cases are against alleged infringement of AstraZeneca's patent rights by the local pharmaceutical firms. The pharmaceutical companies facing the litigation heat are Natco, Ajanta, Torrent, Emcure, Intas, Alkem, MSN, USV, Zydus, Eris and Micro Labs. 

The litigation began after AstraZeneca approached the Court against Natco Pharma's decision to launch generic Dapagliflozin under the brand name ‘Dapnat’ in March 2020. Astra Mentioned that Natco took advantage of the pandemic and launched the drug, and flooded the market with drugs worth Rs 20 crore, the complaint says. In its response, Natco said it has stopped the production and sale of Dapnat till December 31, 2020, and given the difficulty to recall the products it has already sold, the company will give a bank guarantee for Rs 3 crore that can be encashed by AstraZeneca in case of a Court verdict in favour of the MNC.

The litigations took a new turn after five companies - Zydus Healthcare, MSN laboratories, Eris Life Sciences, USV Limited and Alkem Pharma- announced plans to launch respective branded generic versions of Dapagliflozin after the expiry of the basic patent on October 2, 2020.

The ‘patent infringement’ case(s) are being contested by these generic pharma companies as they argue that the ‘species’ patent would not be upheld by the court.

The basic (genus) patent on Dapagliflozin - which generated $1.54 billion through global sales under brand names Farxiga and Forxiga in 2019 - expired on October 2, 2020 in India, it is still protected by a more specific (species) patent till May 15, 2023. Indian firms are contesting the second patent claim. 

After a series of hearings, Judge Jayant Nath delivered his judgement today for Intas and Alkem denying the Injunction (as prayed by AstraZeneca).

Judge Jayant Nath has tried explaining all the arguments and the evidences and affidavits placed before him for this hearing. The below-mentioned summary shows some exerts from his well-reasoned judgement.

The actions concern two patents of Dapagliflozin - i.e. the genus patent i.e. IN 147 and the species patent i.e. IN 625. These aforementioned patents have corresponding patents in the USA i.e. US 126 [which is the genus patent] and US 117 [which is the species patent] the Indian genus patent i.e. IN 147 expired on 02.10.2020. The Indian species patent i.e. IN 625 expires on 15.05.2023.

The prayers made in the suit actions including the captioned interlocutory applications seek injunction against purported infringement of not only IN 147 but also of IN 625. The suit actions were filed on 30.09.2020 i.e. two days prior to expiry of validity period of IN 147 which, as indicated above, ended on 02.10.2020.

-       Apart from the plaintiffs (innovators), DAPA is being marketed with the permission of the plaintiffs by two entities namely Sun and Abbott.

-       Sun and Abbott are licensee of the patents. However, the generics (defendants) assert that they’re only distributors.

Judge quotes various sections of Patent Act to challenge the patent viz section 25(1) and 25 (2), section 64 and section 12 and 13 to state that an interested party has various options at the stage of grant of patent to challenge its validity and says further – using the same, quite clearly, irrespective of when the challenge is laid, the challenger [i.e. the person interested] can put the patent in jeopardy.

He further notices that - First, there is a period of overlap between the genus patent i.e. IN 147 and the species patent i.e. IN 625. The innovators waited till the IN 147 expired.

The Judge further quoted the earlier Roche vs Cipla judgement to state that at Preliminary Injunction (PI) hearing, the invalidity need not be examined. It should be done at trial.

The judge then describes whether the suit patents are vulnerable…

As per him, the challenge to the species patent i.e. IN 625 is, broadly, laid on the following five grounds.

1.     IN 147 is expired on 2.10.2020 i.e. genus patent so it cannot be protected by sec 53(4) of the Act.

2.     IN 625 is vulnerable to revocation under Section 64(1)(a) read with Section 13(1)(b) of the Act on the ground of lack of novelty in view of prior claiming by the genus patent i.e. IN 147

3.     IN 625 is vulnerable to revocation under Section 64(1)(a) read with Section 13(1)(b) of the Act on the ground of lack of novelty in view of prior claiming by the genus patent i.e. IN 147

4.     IN 625 is vulnerable to revocation under Section 64(1)(a) read with Section 13(1)(b) of the Act on the ground of lack of novelty in view of prior claiming by the genus patent i.e. IN 147 technical advance or economic significance and is obvious to a person skilled in the art.

5.     IN 625 is vulnerable to revocation under Section 64(1)(a) read with Section 13(1)(b) of the Act on the ground of lack of novelty in view of prior claiming by the genus patent i.e. IN 147.

Then the Judge quoted few paras from the said patents which mentions that Dapagliflozin is covered by Markush claims of the IN’147.

He further mentions that, the fact that the plaintiffs have taken out an infringement action both for IN 147 and IN 625 is a sufficient clue, at least at this juncture, that DAPA is claimed in both suit patents.

In the present case, the Indian genus patent i.e. IN 147 bears the priority dates 12.10.1999 and 05.04.2000 whereas the Indian species patent i.e. IN 625 bears 20.05.2002 as its priority date. For the purposes of Section 64(1)(a) this ingredient is sufficient Therefore, as long as the defendant can establish that the inventions so far claimed in any claim of the complete specification [in this case IN 625] was claimed in a valid claim of an earlier priority date contained in the complete specification of another patent [i.e. IN 147] – a ground for revocation is made out…

He further quoted UK Regeneron judgement Viz “The Court observed that “in order to patent an inventive product the patentee must be able to demonstrate (if challenged) that a skilled person can make the product by the use of teachings disclosed in the patent coupled with common general knowledge which is already available at the time of priority date without having to undertake undue experimental burden or apply any inventiveness on their own”. This requirement, according to the UK SC, is labelled as sufficiency…Applying this test, the Court culled out certain principles which are set out in paragraph 56 of the judgement.”

Applying these principles, it would have to be said that the arguments of the plaintiffs that DAPA was not claimed in IN 147 seem to be untenable at this stage. This Regeneron decision in Judge’s view has great persuasive value than other recent cases…

Thus he stated that -“It must be stated that it was portrayed on behalf of the plaintiffs that the genus patent i.e. IN 147 ringfenced certain compounds which were disclosed only when the species patent i.e. IN 625 was granted, which would, essentially, mean that the written description/complete specification of IN 147 covered DAPA but did not disclose it.”

Further, according to him, given the aforesaid discussion, a credible defence to the infringement action is set up by the generics.

Then he goes to another aspect of discussion to find that whether the said challenge laid to IN 625 on the ground that it was anticipated by what was published or publicly known from IN 147.

He reports that - “the PCT publication date of IN 147 is 19.04.2001 which is well before, as noted above, the priority date of IN 625, that is, 20.05.2002. It is contended on behalf of the defendants that since DAPA is both claimed and “fully and particularly described” as required under Section 10(4)(a) of the Act as a part of its complete specification, there is a credible case that DAPA was known and, therefore, vulnerable under Section 64(1)(e).”

Thus, he recorded that based on the comparison of written descriptions of WO’128 and IN 625, it was contended that to the man of science of ordinary skill but otherwise interested in the field of organic/medicinal chemistry having reasonable experience, DAPA was not new and was known prior to the priority date of IN 625.

In answer to this argument, the other side mention that even if the prior art referred to infinite number of molecules, a person skilled in the art would be able to narrow it down to 8 molecules. In support of this submission, they have, to a large extent, relied upon the affidavit of their expert witness i.e. one, Dr. Stephen F. Martin.

This side, on the other hand, have relied upon an affidavit of one, Dr. Easwaran dated 18.10.2020 to contend that WO’128 which is the PCT equivalent of the suit patent IN 147 would have structures which would cover millions of compounds and, therefore, going by the Markush formula they would have to be taken down and made one by one. This would take a lifetime. It was also contended that substitutions indicated by Dr. Martin, such as, A, CH-2, R1 had no obvious logic and, therefore, could only be carried out by hindsight wisdom.

The Judge notes further that this issue should be tested at the trial.

The Judge then goes to check the grounds for revocation whether IN 625 involves inventive step.

In his words –“A comparison of the complete specifications/descriptions of Indian genus patent i.e. IN 147 and Indian species patent i.e. IN 625 shows that there is no technical advance of the latter over the former. This is clearly evident if one were to peruse the following extracts from Indian genus patent i.e. IN 147 and Indian species patent i.e. IN 625.”

The innovator’s sought to get over this by seeking to rely upon Dr. Washburn’s affidavit of April 2020 which was filed on 12.10.2020 to show technical advance.

Finally he summarizes this point as - “what emerges is this: that post priority date evidence which has been furnished in Dr. Washburn's affidavit to show technical advance can only be taken into account to confirm the existence of technical effect which is found embedded in the specification of IN 625 and is capable of being understood by a skilled person having common general knowledge and not to rely upon the same to establish its effect for the first time.”

As the last aspect, he discusses requirements of section 8 of the Patents Act.

He also noted that for the Innovators only after filing terminal disclaimer, the said species patent was accepted by USPTO, and that US 117 (species patent) was granted on 20.09.2002. The generics alleged that this information was not given to Indian Patent Office. In answer, the innovators contended that Patent Office was aware of the same as CIP application at USPTO.

Then the judge quotes different judgements of foreign courts to throw the light on this aspect. He then reports that - “A perusal of different judgements as discussed in his (foreign judge’s) judgement, would show that while terminal disclaimers are not treated as admissions, they are taken into account to ascertain the prosecution history of the patent i.e. the reason as to why the patentee chose to narrow down its claim. Thus, while terminal disclaimer filed by a patentee is not treated as a complete bar against the defence of non-obviousness, depending on facts, it can operate as estopped by conduct.”

Then he gives his opinion by saying – “to my mind, as to whether or not the Court would, ultimately, revoke the suit patents for failure to furnish information as sought for by the IPO would be ruled upon by trial.”

Followed by these, he then switches over to the arguments raised concerning the balance of convenience, and irreparable harm. He records that in his view, if, as held by him above, the defendants have been able to set up a credible challenge and/or establish, at least at the preliminary injunction stage, the vulnerability of the suit patents, even if the balance of convenience is in favor of the plaintiffs, the injunction cannot be granted.

On the other hand, if the plaintiffs had established a strong prima facie case for grant of a preliminary injunction, they would still have to satisfy the Court as to whether or not balance of convenience was in their favor and that denial of interim relief would cause irreparable damage.

He summarizes by mentioning, - “thus depriving the defendants, at this stage, from manufacturing and selling their drugs, when, during the validity period of the genus patent i.e. IN 147 they largely held themselves in check would, in my opinion, not be appropriate, especially, when they have set up a credible challenge to the suit patents.”

He also addresses the public interest issue before final concluding his judgement.

Public Interest

He’s recorded the prices as made available to him of the innovators and that of Intas and Alkem and shown that clearly the difference in prices of drugs ranges between 250% to 350% (Innovator’s price is this much higher than generics). Therefore, as is apparent, if defendants were allowed to manufacture and market their drugs, it would be far cheaper.

He then finally concludes by denying the injunction and asking the generics to maintain the sales record as audited till further full trial in case in first quarter next year.

Therefore, following this one, most likely, INTAS and Alkem and possibly other generics would be able to enter the market early.

I’ve also enclosed the 84 page judgement for your reference herewith.

Thus it seems that for Indian Pharma Generics, this has become …"Walking on the known path…!”