Astrazeneca denied injunctions in patent infringement suits with respect to the drug DAPAGLIFLOZIN

AstraZeneca AB and AstraZenca Pharma India Limited (the Plaintiffs) have filed patent infringement suits against a dozen generic medicine manufacturers in India to prevent them from manufacturing the generic versions of dapagliflozin (DAPA), a medicine for treating diabetes. However, it was recently denied interim injunctions in the suits filed against Torrent, MSN, USV, Zydus, Eris and Micro Labs (the Defendants) by way of the order of the Delhi High Court[1] dated November 18, 2020.

About the suit patents:

The suit patents of the Plaintiffs claim to pertain to DAPA which is used for treatment of type-II diabetes and is claimed to be protected by way of Indian patent 235625 [“IN 625”] which is the species patent of Indian patent 205147 [“IN 147”], the genus patent. It is pertinent to note that the patent term for IN 147 expired on October 02, 2020 while the patent term for IN 625 is valid till May 15, 2023.

In furtherance of the suit for infringement, the Defendants filed a counterclaim for revocation against the Plaintiffs challenging the validity of IN 625 on several grounds under Section 64 of the Patents Act, 1970 (the Act). A brief summary of the grounds raised in the counterclaim for revocation filed by the Defendants and the submissions of the Plaintiffs is as below:

Defendants’ contentions:

Disclosure of the species patent in the genus patent

● IN 625 ought to be treated as a patent of addition and not an independent patent since its corresponding US application is a continuation-in-part application - (US 6515117 (US 117) equivalent to IN 625)} and consequently ought to have expired on 2nd October, 2020 (i.e. with the genus patent);

● The species patent (IN 625) is already disclosed in the genus patent (IN 147) and hence the same is not patentable;

● The Plaintiff’s pleadings (discussed below) that IN 625 is ‘covered’ under the genus patent IN 147 i.e., under its Markush Structure but the DAPA claimed in IN 625 is not ‘disclosed’ in IN 147 cannot be accepted as claims cannot be larger than the disclosure in view of the decision in Novartis AG vs. Union of India and Ors.[2];

Obviousness and lack of technical advancement of the species patent

● The invention disclosed in IN 625 is obvious to a skilled person and that DAPA is disclosed in the genus patent;

● IN 625 lacks technical advancement to qualify as a selection patent or a species patent.

Failure to comply with Section 8 of the Act

Section 8(1) of the Act:

● IN 625 is liable to be revoked on grounds of failure of the Plaintiffs (Patentee) to comply with the duty laid down under Section 8 of the Act which calls for the applicant of a patent application to furnish complete details before the Indian Patent Office (IPO) of any foreign application filed for the same or essentially the same invention;

Section 8(2) of the Act:

● The Plaintiffs failed to disclose to the IPO and the Court that in the corresponding US species patent (US 6515117 equivalent to IN 625), the USPTO had raised an objection with respect to the claims 1 to 17 of US 6515117 to be covered under the earlier US genus patent (US 6414126 equivalent to IN 147). In order to overcome the provisional refusal, the Plaintiffs had filed a terminal disclaimer before the USPTO and accepted that the species patent shall be enforceable only during such period as the prior genus patent was valid;

● This concealment of the provisional refusal (office action) of the USPTO before the IPO, disabled it to form a complete opinion regarding obviousness and therefore IN 625 is invalid/ ought to be revoked.

Admissions made in Orange Book and Patent working statement (Form 27)

● The Plaintiffs are bound by the admissions made in the Orange Book and Form 27 wherein identical working statements were filed for the patents IN 147 and IN 625 listing DAPA as the compound which is worked.

Anticipation

Prior claiming[3]

● IN 625 is anticipated due to the prior broader claims in IN 147 (which has an earlier priority date as compared to the priority date of IN 625) and hence ought to be revoked.

Prior publication

● IN 625 is liable to be revoked on the grounds of anticipation by prior publication in view of WO 2001/27128 (WO 128), the corresponding PCT application of the genus patent IN 147, published on April 19, 2001 (which is earlier than the priority date of IN 625 being May 20, 2002).

Plaintiffs’ Contentions:

Lack of ‘disclosure’ of the species patent in the genus patent

● The invention disclosed in IN 625 is not disclosed in IN 147 and accordingly, the said patent ought to be an independent patent and not a patent of addition;

● IN 147 bears a Markush Structure and does not ‘disclose’ DAPA, which is actually disclosed in IN 625 and DAPA is also not disclosed in any of the 80 examples in the specification of IN 147;

● IN 147 covers the basic core, structure, scaffold (pharmacophore) showing three rings, one sugar and two phenyl, connected to each other in a certain way, and having multiple variables on specific positions of the two phenyl rings. If the total number of permutations are worked out, then several millions of compounds are covered by this basic core. Out of this basic core only 80 compounds were synthesized and identified in the genus patent specification in IN 147, which can be treated as disclosed in IN 147;

● On the expiry of the genus patent (IN 147) on 2nd October 2020, only the inventive concept of the basic, core structure and the disclosed 80 examples went into the public domain and no further.

Inventive step and technical advancement of the species patent

● The corresponding US species patent US 117 (corresponding to IN 625) being accepted as a continuation in part application to the genus patent US 126 (corresponding to IN 147) by the USPTO implies that the species patent discloses a technical advancement over the genus patent as disclosure of additional matter is a prerequisite to entertain a continuation in part application before the USPTO (as per MPEP 201.08);

● With respect to the inventive step of IN 625, the Plaintiffs submitted Affidavits of its Expert witnesses establishing that a person of the ordinary skill in art on seeing IN 147 could not have reached DAPA.

Compliance under Section 8 of the Act

● The disclosure of US 117 being a continuation in part application was made in the specification of IN 625;

● All material evidence was placed before the Examiner to examine the non- obviousness of IN 625 and that the Examiner was satisfied in light of the Plaintiffs' arguments in its response;

● The requirements under Sections 8(1) and 8(2) of the Act were met by the Plaintiff.

Statements made in Orange Book and Patent working statement (Form 27)

● The Plaintiff’s statements in Form 27 and Orange Book nowhere admitted that DAPA was ‘disclosed’ in the genus patent (IN 147);

● Coverage is not the same as disclosure: Defendants in their pleadings have clearly admitted that DAPA was first disclosed in US 117 (equivalent to IN 625). Therefore, coverage cannot be deemed to be disclosure by the Defendants.

The claimed invention is novel

● Only disclosure (and not coverage) of an invention in a prior art document alone destroys novelty of the subsequent patent for the said invention making it vulnerable to invalidity;

● For the invention disclosed in IN 625 to be revoked on account of being anticipated by prior claiming, it should have been claimed in the complete specification having a priority date earlier than IN 625 and the same has not been proved by the Defendants.

Court’s Decision and Reasoning:

At this stage, the Hon’ble Court analyzed the issues and arguments presented by the parties and presented a prima facie opinion for the purpose of addressing the preliminary issue of whether an interim injunction ought to be granted against the Defendants. The following is a brief summary of the Court’s analysis and conclusion:

Lack of ‘disclosure’ of the species patent in the genus patent

● The invention claimed in IN 625 is not ‘disclosed’ in IN 147. Though example 12 of IN 147, which was relied upon by the Defendants’ to have disclosed DAPA, indicated Chlorine as one of the preferred halogens, however, it claimed a methoxy substitute and not an ethoxy substitute as disclosed in IN 625;

● IN 625 showed a substantial advantage over the claims in IN 147 as the claims in IN 147 did not disclose any viable drug even in Example 12 and that DAPA was disclosed only in IN 625.

● In the specification of IN 147, the composition of DAPA is not mentioned and that only the general properties of the Markush structure were claimed;

● Drug approval for DAPA by the Plaintiffs(patentee) was obtained on the basis of IN 625 and not IN 147.

The claimed invention is novel

● IN 625 was not prima facie liable to be revoked on account of prior claiming in the genus patent IN 147 as DAPA was neither claimed nor disclosed in the specification of the genus patent.

Statements made in Orange Book and Form 27

● The Court rejected the Defendants’ argument that the admission of the Plaintiffs in the Orange Book and Form 27 with respect to its genus patent amounted to the disclosure of the species patent as the Plaintiffs stated that the patent had worked only after it obtained the marketing approval for DAPA.

Obviousness and lack of technical advancement of the species patent

● IN 625 is prima facie vulnerable to be revoked on the grounds of obviousness in view of Example 12 of IN 147 as on account of both methyl as well as ethyl being lower alkyls, a person skilled in the art would have been persuaded to replace methyl with ethyl in order to find if similar results will ensue;

● However, the lack of patentability could not have been presumed on the ground that since a terminal disclosure was filed for the species patent, it was indistinct from the genus patent.

Failure to comply with Section 8 of the Act

Section 8(1) of the Act:

● The Plaintiffs had substantially complied with the requirement of Section 8(1) of the Act as the details of the corresponding patent US 6515117 had been furnished along with the claims and the said information was also available on the websites and was thus deemed to be within the knowledge of the IPO;

Section 8(2) of the Act:

● The Plaintiffs had prima facie failed to comply with the requirements of Section 8(2) of the Act;

● The duty imposed by the Act and the IPO by way of the examination report (office action) including the details regarding the search and/ or examination reports including claims of the application allowed for substantially the same invention filed before the USPTO, EPO, JPO, etc. (as required under Section 8(2) of the Act) were not met by the Plaintiffs;

● The Plaintiffs failed to submit the provisional refusal issued by the USPTO on the ground of double patenting wherein the Plaintiffs had filed a terminal disclosure. Thus, the Plaintiffs having failed to bring to the notice of the IPO the objection raised by the USPTO, did not comply with Section 8(2) of the Act and therefore IN 625 is prima facie vulnerable to be cancelled.

Conclusion: Denial of interim injunction in favor of the Plaintiff

● The Court need not adjudge the actual validity of the suit patent but whether the suit patent was vulnerable to be revoked on credible grounds.

● Therefore, the Defendants’ having prima facie laid a credible challenge to the validity of the suit patent on the grounds of obviousness and non-compliance with Section 8(2), the Plaintiffs were not entitled to an interim injunction.

Neetika Gandhi

Senior Associate

neetika.gandhi@iprattorneys.com

[1] CS(COMM) 323/2020, 346/2020, 414/2020, 418/2020, 419/2020,426/2020 order passed on November 18, 2020 [2] (2013) 6 SCC 1 [3] the claims under the subject matter form part of the complete specifications of any Indian Application having a priority date earlier than the filing date of the complete specification in the subsequent application