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

Delhi High Court (Division Bench), 2015 (FAO (OS) 190/2013, decided on 20 March 2015)

BACKGROUND

The dispute concerned Indian Patent No. IN 209816, held by Merck Sharp & Dohme (MSD), relating to the anti-diabetic drug Sitagliptin, a DPP-IV inhibitor used in the treatment of Type-2 Diabetes Mellitus. MSD marketed the drug in India under the brands Januvia and Janumet, while Glenmark launched competing products Zita and Zitamet, containing Sitagliptin Phosphate Monohydrate (SPM).

MSD instituted infringement proceedings seeking an ad-interim injunction, alleging that Glenmark’s products infringed its product patent covering Sitagliptin and its pharmaceutically acceptable salts. The Single Judge refused interim relief, leading to an appeal before the Division Bench.

The case required the Court to examine, in depth, the scope of patent claims, sufficiency of disclosure, salt versus free-base doctrine, and the role of Section 3(d), Section 8, and Section 48 of the Patents Act, 1970, at the interim stage.

ISSUES FOR DETERMINATION

The Division Bench considered the following principal issues:

How the claims of Patent IN 209816 should be properly construed.
Whether the patent sufficiently disclosed and enabled Sitagliptin free base and/or Sitagliptin Phosphate Monohydrate.
Whether Glenmark’s products prima facie infringed the suit patent.
Whether the patent was vulnerable to revocation under Section 64, including for insufficiency, over-breadth, and non-disclosure under Section 8.
The appropriate standard for granting ad-interim injunctions in patent infringement suits.

KEY HOLDINGS OF THE COURT

The Court held that grant of a patent carries no presumption of validity, even at the interim stage.
Patent claims must be construed in light of the complete specification, and claims cannot extend beyond what is enabled and disclosed.
While Sitagliptin free base was disclosed through reaction schemes in the specification, the question whether Sitagliptin Phosphate Monohydrate was sufficiently disclosed raised serious triable issues.
The Court emphasised that mere claim language covering “pharmaceutically acceptable salts” is insufficient unless supported by enabling disclosure.
MSD failed to establish a strong prima facie case of infringement, particularly given its own abandonment of separate patent applications for the phosphate salt.
Consequently, refusal of ad-interim injunction was upheld, and the matter was left to be decided at trial.

STATUTORY PROVISIONS

Section 48, Patents Act, 1970 (Rights of Patentee)

Judicial Interpretation:
Exclusive rights under Section 48 arise only within the scope of validly claimed and disclosed subject matter. Over-broad claims unsupported by disclosure cannot be enforced.

Section 10(4), Patents Act, 1970 (Complete Specification)

Judicial Interpretation:
The specification must fully and fairly describe the invention and the method of performing it. Disclosure is the quid pro quo for monopoly, and courts will not permit claim expansion beyond enablement.

Section 64(1)(h), (i), (j), Patents Act, 1970 (Grounds for Revocation)

Judicial Interpretation:
At the interim stage, credible challenges based on insufficiency, over-breadth (Markush-type claims), and suppression of material information are sufficient to deny injunctive relief.

Section 8, Patents Act, 1970 (Disclosure of Foreign Applications)

Judicial Interpretation:
Failure to disclose corresponding foreign applications and their prosecution status is a serious statutory lapse, capable of affecting both validity and interim enforcement.

Section 3(d), Patents Act, 1970

Judicial Interpretation:
The Court reaffirmed that Section 3(d) prevents indirect monopolisation of new forms (such as salts) through broad claims in earlier patents, particularly where later applications for such forms were abandoned.

CLAIM CONSTRUCTION AND DISCLOSURE DOCTRINE

A central contribution of this judgment lies in its rigorous approach to claim construction:

Claims are not read in isolation but as part of the entire specification.
The patent must enable a person skilled in the art to make the invention without undue experimentation.
The Court rejected the idea that coverage can exceed disclosure, echoing the Supreme Court’s reasoning in Novartis AG v. Union of India.

The Court carefully analysed reaction schemes, examples, and chemical pathways to assess whether the Sitagliptin free base and its salts were truly disclosed.

INTERIM INJECTION STANDARDS

The judgment provides authoritative guidance on interim relief in patent cases:

Courts must exercise heightened caution in granting ad-interim injunctions in technically complex patent disputes.
Even minimal doubt as to validity, scope, or infringement is sufficient to deny interim relief.
“Swift justice” cannot override procedural fairness and evidentiary scrutiny in patent litigation.

DOCTRINAL SIGNIFICANCE

This case is doctrinally significant because it:

Reinforces the disclosure–monopoly bargain in Indian patent law
Prevents enforcement of over-broad pharmaceutical claims
Clarifies the role of abandoned applications in infringement analysis
Strengthens the jurisprudence on Section 8 compliance
Aligns Indian patent injunction standards with international best practices

Merck Sharp & Dohme v. Glenmark is a landmark as it –

Represents one of the most detailed Indian judicial examinations of pharmaceutical claim construction
Prevents strategic extension of patent monopolies through salt forms
Sets a high evidentiary threshold for interim patent injunctions
Continues the post-Novartis trajectory of strict patent scrutiny

It remains a leading authority for courts and practitioners dealing with pharmaceutical patents, disclosure obligations and interim relief.