Merck Sharp & Dohme Corporation & Anr. v. Glenmark Pharmaceuticals Ltd.

High Court of Delhi at New Delhi | Decided: 20 March 2015 FAO (OS) No. 190 of 2013 Bench: Hon’ble Mr. Justice S. Ravindra Bhat & Hon’ble Mr. Justice Najmi Waziri (Division Bench) Citation: 2015 SCC OnLine Del 8227 | (2015) 62 PTC 193 (Del) (DB)

Background

Merck Sharp & Dohme Corporation, a company incorporated in New Jersey, United States of America, is the registered proprietor of Indian Patent No. 209816, bearing the title “Beta-Aminotetra Hydroimidazo-(1,2-A) Pyrazines and Tetrahydrotrioazolo (4,3-A) Pyrazines as Dipeptidyl Peptidase Inhibitors for the Treatment or Prevention of Diabetes.” The patent relates to the anti-diabetic drug Sitagliptin, a first-in-class inhibitor of the enzyme Dipeptidyl Peptidase-IV, used in the management of Type-2 Diabetes Mellitus. The DPP-IV enzyme breaks down incretin hormones GLP-1 and GIP, which stimulate insulin secretion after food intake. By inhibiting DPP-IV, Sitagliptin allows these hormones to remain active longer, thereby stimulating insulin release and suppressing glucagon in a glucose-dependent manner, thus avoiding the risk of hypoglycemia associated with older anti-diabetic agents. MSD claimed to have spent over nine years of research and substantial monetary investment in developing the drug. The Indian patent application was filed on 6 January 2004, with the international application PCT/US2002/021349 filed on 5 July 2002 and a priority date of 6 July 2001. The patent was finally granted on 6 September 2007.

MSD marketed Sitagliptin in India in the form of its phosphate monohydrate salt under the brand name Januvia and in combination with Metformin Hydrochloride under the brand name Janumet. The second plaintiff, Sun Pharmaceutical Industries Limited, was MSD’s marketing and distributing licensee, selling the same drugs under the brand names Istavel and Istamet respectively. MSD stated that it had launched Januvia in the Indian market in April 2008 at approximately Rs. 43 per pill, roughly one-fifth of its price in the United States, and had invested approximately Rs. 10 crores in patient access and education programmes. The suit patent had 20 claims, of which Sitagliptin was covered in 13 claims. Claim 1 embraced all forms of Sitagliptin including all stereoisomers, all salts and solvates, and the free amine. Claim 19 specifically covered Sitagliptin or a pharmaceutically acceptable salt thereof, which included the R-stereoisomer in its phosphate monohydrate salt form used in the commercial product.

Glenmark Pharmaceuticals Limited, the defendant and respondent, is a research-driven multinational pharmaceutical company with operations in approximately 80 countries, 6 research and development centres and 13 manufacturing facilities. Glenmark launched products under the brand names Zita, containing Sitagliptin Phosphate Monohydrate as the active pharmaceutical ingredient, and Zitamet, containing Sitagliptin Phosphate Monohydrate in combination with Metformin Hydrochloride. MSD alleged that Glenmark’s products infringed its suit patent because Sitagliptin and its pharmaceutically acceptable salts were covered by the patent claims, and that Glenmark could not manufacture Sitagliptin Phosphate Monohydrate without first producing the Sitagliptin molecule itself, thereby infringing the suit patent. Importantly, Glenmark’s own United States Patent No. 8334385, granted on 18 December 2012 for a process for the preparation of R-Sitagliptin and its pharmaceutical salts, expressly acknowledged Sitagliptin as the foundational active compound for its commercial product, which it confirmed was Sitagliptin Phosphate sold under the brand name Januvia.

MSD filed the present suit before the Delhi High Court on 1 April 2013 seeking permanent injunction, damages, rendition of accounts and delivery up. Glenmark was on caveat and appeared at the first hearing on 2 April 2013. The Single Judge heard both sides and dismissed the application for ad-interim injunction by an order dated 2 to 5 April 2013, finding that MSD had not sufficiently pleaded how Sitagliptin Phosphate Monohydrate was merely a new form of Sitagliptin medically equivalent to it, and that MSD’s own pursuit of a separate patent application for Sitagliptin Phosphate Monohydrate in India Application No. 5948/DELNP/2005 which was ultimately abandoned amounted to an admission that the two were distinct inventions. MSD appealed to the Division Bench in FAO (OS) No. 190 of 2013. The Division Bench, after directing both parties to file full pleadings and documents and hearing extensive arguments, proceeded to decide the appeal as a final determination of the interlocutory application.

Glenmark’s defence before the Division Bench was multifaceted. It challenged the validity of the suit patent under Section 64 on grounds including: that the patent was a Markush claim covering approximately 4.9 billion compounds making it overbroad and invalid for insufficiency; that the Sitagliptin free base was not specifically disclosed in the specification, only the Hydrochloride salt being exemplified in Example 7; that the Sitagliptin free base lacked industrial applicability as it was itself unstable and unsuitable for pharmaceutical development; that the patent was anticipated by prior art; and that MSD had failed to disclose its subsequent patent applications particularly Application No. 5948 for Sitagliptin Phosphate Monohydrate and Application No. 1130 for crystalline forms of the phosphate salt constituting suppression of material facts and non-compliance with Section 8 of the Patents Act, 1970.

Issues for Determination

Whether the claims of Indian Patent No. 209816 sufficiently disclosed and enabled the Sitagliptin free base, and whether the patent constituted a valid Markush claim covering all pharmaceutically acceptable salts of Sitagliptin including Sitagliptin Phosphate Monohydrate.
Whether the Sitagliptin free base had prima facie industrial applicability as a patentable compound within the meaning of Section 2(1)(ac) of the Patents Act, 1970, notwithstanding Glenmark’s contention that it was inherently unstable and commercially unusable without conversion to a salt form.
Whether MSD’s abandonment of its separate patent applications for Sitagliptin Phosphate Monohydrate in India constituted an admission that Sitagliptin Phosphate Monohydrate was a distinct and independent invention not covered by the suit patent, and whether this abandonment affected the scope of the suit patent claims on proper construction.
Whether Glenmark’s manufacture and sale of Zita and Zitamet containing Sitagliptin Phosphate Monohydrate prima facie infringed the suit patent, specifically whether the production of Sitagliptin Phosphate Monohydrate necessarily involved the prior manufacture of the Sitagliptin molecule covered by the suit patent.
Whether MSD’s failure to disclose certain subsequent patent applications including Applications Nos. 5948 and 1130 filed in India constituted a violation of Section 8 of the Patents Act, 1970, and whether such non-disclosure rendered the suit patent vulnerable to revocation under Section 64(1)(m), thereby disentitling MSD from interim injunctive relief.
Whether the grant of a patent carries a presumption of validity at the interlocutory stage, and what is the correct standard for the grant of ad-interim injunctions in technically complex pharmaceutical patent infringement proceedings.
Whether the balance of convenience, public interest in access to anti-diabetic medicines, and the risk of irreparable harm favoured the grant or refusal of an ad-interim injunction, and whether the present case was distinguishable from the public interest framework established in the Cipla v. Roche line of cases.

Key Holdings of the Court

the Division Bench held that the grant of a patent carries no presumption of validity at the interlocutory stage. Relying on the Supreme Court’s observation in Biswanath Prasad Radhey Shyam v. Hindustan Metal Industries that the grant of a patent does not guarantee its validity, the court confirmed that this principle applies with equal force to interim hearings, and that a defendant may challenge the validity of a patent as a defence to an infringement suit under Section 107 of the Patents Act, 1970.
the court held that the Sitagliptin free base was prima facie sufficiently disclosed in the suit patent. Examining the detailed reaction schemes and examples in the complete specification particularly Scheme 6, which disclosed a step-by-step chemical pathway from known compounds to the Sitagliptin free base as the end product the court found that the specification enabled a person of ordinary skill in the pharmaceutical art to arrive at the Sitagliptin free base without undue experimentation. The court rejected Glenmark’s argument that only the Sitagliptin Hydrochloride salt was disclosed, noting that the active therapeutic component was the Sitagliptin free base and that the attached salt was merely an inert carrier with no independent therapeutic value.
the court held that the Sitagliptin free base was prima facie industrially applicable within the meaning of Section 2(1)(ac) of the Patents Act, 1970. The specification disclosed in detail the drug’s function as a DPP-IV inhibitor with a measured IC50 of less than approximately 1 micromolar, identified specific diseases and conditions for which it had therapeutic utility, and provided detailed dosage and administration information. The court found that the instability of the free base as a solid formulation and the consequent need for a salt carrier did not negate industrial applicability the active ingredient retained its therapeutic function regardless of the carrier, and the patent disclosed that it would be combined with a pharmaceutically acceptable carrier for administration.
on the Markush claim challenge, the court held that while the suit patent was undoubtedly a broad Markush claim encompassing a large number of possible compounds, this did not prima facie render it invalid. The court found that the compounds claimed shared a common use as DPP-IV inhibitors and a common chemical structure under the general formula in Claim 1, and that the core invention the Sitagliptin free base as the active DPP-IV inhibitor was sufficiently disclosed. The court acknowledged that the question of whether Sitagliptin Phosphate Monohydrate specifically was disclosed and covered, beyond a generic reference to pharmaceutically acceptable salts, raised a serious triable issue to be determined at trial with expert evidence.
on the critical question of whether MSD’s abandonment of its separate patent application for Sitagliptin Phosphate Monohydrate affected the scope of the suit patent, the court held that claim construction must be conducted objectively on the words used by the inventor and cannot be influenced by the subsequent subjective conduct of the patentee. The abandonment of a separate patent application cannot remove what is objectively covered by an earlier patent, nor can it include something objectively excluded. The court held that Section 3(d) does not operate backwards such that two independent patent claims are to be construed in reference to each other each claim is regulated by its own terms.
on the Section 8 non-disclosure issue, the court held that the obligation under Section 8 is expressly limited to applications filed in countries outside India. Applications filed within India including Applications Nos. 5948 and 1130 did not fall within the scope of Section 8, and their non-disclosure could not constitute a ground for revocation under Section 64(1)(m). The court further noted, following the Division Bench’s decision in Maj. (Retd.) Sukesh Behl v. Koninklijke Philips Electronics, that revocation under Section 64(1)(m) is discretionary and not automatic even where a Section 8 violation is established.
on prima facie infringement, the court held that Glenmark prima facie infringed the suit patent. Glenmark’s own United States patent expressly stated that Sitagliptin was the active free base upon which its process patent was built, and acknowledged Januvia as the commercial manifestation. The production of Sitagliptin Phosphate Monohydrate necessarily required the prior manufacture of the Sitagliptin molecule itself, which was the subject of the suit patent. Under Section 48(a) of the Patents Act, 1970, manufacturing a patented product without the patentee’s consent constitutes infringement, regardless of whether further steps are taken to convert it into a salt.
on the balance of convenience and public interest, the court held that the present case was distinguishable from the Cipla v. Roche framework. Unlike the cancer drug Tarceva, which was priced at a level entirely beyond the reach of most Indian patients, MSD had launched Januvia at approximately one-fifth of its price in the United States, and the price differential between MSD’s product and Glenmark’s was approximately 30%. The court found that Sitagliptin, while an important drug for Type-2 Diabetes, was not a life-saving drug in the same sense as a cancer drug and was not listed in the WHO’s Model List of Essential Medicines. The balance of convenience lay in MSD’s favour, particularly given the risk of irreparable market harm to the patentee if the infringer were permitted to operate at depressed prices during the pendency of the trial.
the Division Bench set aside the Single Judge’s order dismissing the injunction application and granted the ad-interim injunction restraining Glenmark from further selling, distributing or dealing in Zita, Zitamet and associated products. Glenmark was permitted to sell existing stocks already in the market. MSD was directed to file an undertaking to compensate Glenmark for all losses if the suit were ultimately dismissed, and Glenmark was directed to file detailed accounts of its earnings from the infringing products. The suit was directed to proceed to expedited trial with directions for limited expert oral evidence and the appointment of a technical expert under Section 115 of the Patents Act.

Statutory Provisions Involved

Section 48(a) of the Patents Act, 1970 confers upon a patentee whose patent relates to a product the exclusive right to prevent third parties who do not have consent from making, using, offering for sale, selling or importing for those purposes that product in India. The court applied this provision to hold that Glenmark’s manufacture of Sitagliptin Phosphate Monohydrate which necessarily required the prior production of the Sitagliptin molecule constituted infringement of the suit patent regardless of the additional steps involved.

Section 10(4) of the Patents Act, 1970 requires that every complete specification shall fully and particularly describe the invention and its operation or use, disclose the best method of performing the invention known to the applicant, and end with a claim or claims defining the scope of the invention claimed. The court applied the requirement of enabling disclosure from Section 10(4) to assess whether Sitagliptin free base and Sitagliptin Phosphate Monohydrate were sufficiently disclosed in the suit patent, relying on the Supreme Court’s articulation in Novartis AG v. Union of India that coverage in a patent cannot exceed its disclosure.

Section 2(1)(ac) of the Patents Act, 1970 defines capable of industrial application as meaning that the invention is capable of being made or used in an industry. The court examined this provision in the context of Glenmark’s challenge that the Sitagliptin free base had no industrial applicability on account of its inherent instability as a standalone solid formulation, and held that the therapeutic function of the compound as a DPP-IV inhibitor satisfied the industrial applicability requirement regardless of the carrier used for administration.

Section 8 of the Patents Act, 1970 requires a patent applicant who is prosecuting a corresponding application for the same or substantially the same invention in any country outside India to disclose detailed particulars of such foreign application to the Controller and to provide undertakings to keep the Controller informed from time to time of developments in such foreign applications. The court made a significant interpretive ruling that Section 8 is expressly limited to applications filed in countries outside India and does not extend to applications filed within India.

Section 64(1)(m) of the Patents Act, 1970 provides as a ground for revocation that the applicant for the patent has failed to disclose to the Controller the information required by Section 8 or has furnished information that was false to his knowledge in any material particular. The court confirmed, following Sukesh Behl, that the word may in Section 64(1) renders revocation under this ground discretionary rather than automatic, so that a technical breach of Section 8 does not necessarily result in revocation of the patent.

Section 107 of the Patents Act, 1970 provides that every ground on which a patent may be revoked under Section 64 shall be available as a defence in proceedings for infringement of the patent. This provision enabled Glenmark to raise its validity challenges including the Markush overbreadth challenge, the insufficiency challenge and the Section 8 non-disclosure challenge as defences in the infringement suit rather than being confined to separate revocation proceedings.

Section 115 of the Patents Act, 1970 empowers the court to appoint a scientific adviser to assist it in understanding technical aspects of a patent dispute. The court exercised this power by directing the appointment of a technical expert in consultation with the parties to assist in the expedited trial, recognising the complexity of the pharmaceutical chemistry at issue.

Order XXXIX Rules 1 and 2 of the Civil Procedure Code, 1908 govern the grant of temporary and ad-interim injunctions. The court applied the tripartite framework of prima facie case, irreparable harm and balance of convenience to assess the injunction application, while developing a more nuanced six-principle equitable framework to address the specific dimensions of pharmaceutical patent disputes.

Reasoning of the Court

The Division Bench began by making an important procedural observation that would inform its entire approach to the case. It noted, with some concern, that the Single Judge had disposed of the injunction application at the very first hearing on 2 April 2013 without the benefit of full pleadings or substantive evidence from the defendant. The court observed that in technically complex patent disputes, an ex parte or in limine decision on an interlocutory application should be avoided courts should at least require some formal disclosure by the defendant before deciding such applications. Quoting Justice Potter Stewart, the court noted that swift justice demands more than just swiftness, and that excessive haste in complex patent matters risks injustice.

On the question of validity and claim construction, the court’s reasoning proceeded through a careful examination of the complete specification. Addressing the Markush challenge, the court engaged with the tension between the legitimate breadth of pharmaceutical compound patents and the requirement that claims not extend beyond enabling disclosure. Drawing on English patent jurisprudence including the House of Lords decision in Kirin-Amgen and the Court of Appeal decision in Regeneron v. Genentech, the court articulated the principle of purposive construction that patent claims are to be read as communications of inventive ideas to persons skilled in the art, not as mathematical catalogues. The court found that while the suit patent was undeniably broad, the core inventive contribution the Sitagliptin free base as a novel DPP-IV inhibitor was clearly and sufficiently disclosed through Scheme 6 of the specification and the accompanying detailed description of the chemical pathway from known compounds to the final product. The breadth of the Markush claim in encompassing all pharmaceutically acceptable salts was prima facie sustainable because the active therapeutic value resided in the free base and the carrier salts were inert delivery vehicles whose specific properties did not alter the invention’s essential character.

The reasoning on industrial applicability was grounded in the court’s identification of the true subject matter of the invention. The court distinguished between the active pharmaceutical ingredient Sitagliptin and the carrier salt used to administer it. The instability of the free base as a solid formulation, while a genuine technical challenge addressed by the development of Sitagliptin Phosphate Monohydrate, did not negate the therapeutic utility of the compound itself. The court applied the English Court of Appeal’s four-element test from Eli Lilly v. Human Genome Sciences requiring a practical application, a concrete benefit derivable directly from the description, something more than speculative utility, and the ability of a skilled person to reproduce the invention without undue burden and found that the suit patent satisfied all four elements with respect to the Sitagliptin free base.

On the infringement analysis, the court’s reasoning was anchored in a simple but legally decisive observation. Glenmark’s own United States patent filed by Glenmark itself expressly identified Sitagliptin as the foundational active compound in the drug and acknowledged that Sitagliptin Phosphate Monohydrate is manufactured from Sitagliptin. The court found that Glenmark could not simultaneously rely on the Sitagliptin molecule as the basis of its own intellectual property in the United States while denying that it manufactured and used Sitagliptin in India. Since Section 48(a) confers the exclusive right to prevent third parties from making the patented product, and since the manufacture of Sitagliptin Phosphate Monohydrate by Glenmark necessarily involved the prior production of the Sitagliptin molecule, prima facie infringement was established.

The court’s reasoning on the balance of convenience and public interest represented a significant and nuanced development of the framework established by the earlier Cipla v. Roche Division Bench. The court articulated six equitable principles applicable to pharmaceutical patent injunction applications. The first was public interest in access to medicines but the court held that the present case was materially different from Roche v. Cipla because MSD had launched at one-fifth of the US price and the price differential was only 30%, not 300%, and the drug was not life-saving in the same sense as a cancer treatment. The second was public interest in maintaining the integrity of the patent system itself. The third was the risk of irreparable market harm to the patentee if an infringer operates at depressed prices during the trial and prices cannot recover after the patentee ultimately prevails. The fourth was the defendant’s decision to launch the infringing product without first invoking revocation proceedings or seeking a declaration of non-infringement the court found this relevant in assessing the equities at the interim stage, noting that Glenmark had been aware of the suit patent and had opposed MSD’s SPM application in the United States, yet still launched without clearing the way first. The fifth was the undertaking offered by MSD to compensate Glenmark for all losses if the suit were ultimately dismissed, which removed the risk of irreparable harm to the defendant. The sixth was the maintenance of the integrity of the patent system as a driver of pharmaceutical innovation. Taking these principles together, the court held that the balance clearly favoured the grant of an injunction.

Doctrinal Significance

The Merck v. Glenmark judgment is one of the most analytically rich and doctrinally significant pharmaceutical patent decisions in Indian legal history, and its importance operates across several distinct domains of patent law.

The judgment’s contribution to the law of pharmaceutical claim construction is perhaps its most enduring legacy. By articulating a sophisticated framework for assessing the validity and scope of Markush claims in pharmaceutical patents acknowledging their legitimate breadth while insisting on sufficient disclosure of the core inventive contribution the court steered between the twin dangers of construing claims too broadly so as to grant an undue monopoly and construing them too narrowly so as to allow competitors to pick the closest imitation and frustrate the patent. The court’s distinction between the active therapeutic ingredient and the inert carrier salt, and its holding that the patent’s enabling disclosure requirement is satisfied if the core compound is sufficiently taught even if every possible salt form is not individually exemplified, provides important and practically useful guidance for pharmaceutical patent applicants and litigants.

The judgment makes a significant contribution to the jurisprudence on Section 8 of the Patents Act, 1970 by clarifying that the provision’s disclosure obligation is expressly limited to applications filed in countries outside India and does not extend to applications filed within India. This interpretive clarification resolves a tension that had emerged from the Division Bench’s earlier Cipla v. Roche interlocutory observations, which had appeared to suggest a broader obligation. By returning to the plain text of Section 8 and giving the words in any country outside India their literal meaning, the court brought greater certainty to the scope of the disclosure obligation.

The judgment’s development of the balance of convenience framework for pharmaceutical patent injunction applications is also doctrinally important. By identifying six specific equitable principles applicable to such cases and by explicitly distinguishing the present facts from the public interest framework established in Cipla v. Roche, the court introduced a more structured and principled approach to what had previously been a somewhat discretionary and fact-specific exercise. The court’s recognition that the public interest in access to medicines operates differently depending on whether the drug is life-saving, the magnitude of the price differential, and the availability of the drug at accessible prices provides a useful framework for future cases. The holding that an injunction may be appropriate in pharmaceutical cases where the price differential is moderate and the patentee has taken active steps to make the drug available affordably represents an important qualification of the Cipla v. Roche principle.

The court’s treatment of the relationship between a patentee’s abandonment of a separate patent application and the scope of an earlier patent is also significant. By holding that claim construction must be conducted objectively on the words of the patent itself without reference to the patentee’s subsequent conduct or subjective intent, and that Section 3(d) does not operate backwards to affect the construction of prior claims, the court provided clarity on a question that had generated considerable uncertainty in the wake of the Roche v. Cipla litigation. This holding has practical importance for pharmaceutical companies that pursue multiple overlapping patent applications for different forms and formulations of the same active compound.

Finally, the court’s procedural holding that interlocutory applications in complex patent disputes should not be decided ex parte or in limine without at least some formal disclosure by the defendant is an important contribution to the practice of patent litigation. The observation that swift justice demands more than just swiftness, and that excessive haste in technically complex cases risks injustice to both parties, reflects a mature understanding of the demands that pharmaceutical patent litigation places on the judicial process. The court’s direction for the appointment of a technical expert under Section 115 of the Patents Act to assist at trial reinforces the principle that Indian courts must be equipped with appropriate technical assistance to adjudicate pharmaceutical patent disputes fairly and accurately.