Summary: What is the difference between anticipating and obviousness? In a pivotal ruling involving the patent for Semaglutide (the blockbuster compound used to treat Type 2 diabetes), the Delhi High Court sharpened the boundary between various grounds for challenging patent validity.
Introduction
A typical patent infringement matter plays out thus: the patent holder / plaintiff sues for patent infringement, along with an application for an interim injunction to stop the infringer / defendant from manufacturing, selling, or using, the patented process or product; the defendant counters with a challenge to the validity of the suit patent, and if the challenge is successful, the court will decline the interim injunction. Such challenges are usually based on grounds under Section 64 of the Patents Act, 1970 (the “Act”). Some of these grounds are conceptually adjacent but technically distinct, and can be misunderstood as a result, such as anticipation by prior claiming, anticipation by prior publication, and obviousness.
In this context, the Division Bench of the Delhi High Court in Novo Nordisk A/S v. Dr. Reddy’s Laboratories Ltd. (Decision dated 9 March 2026, in FAO(OS) (COMM) 204/2025 & CM APPL. 78607/2025) had occasion to clarify the distinction between some of these grounds, in a case involving the blockbuster compound Semaglutide, used to treat Type 2 diabetes.
Background
Novo Nordisk sued Dr. Reddy’s Laboratories Ltd. for infringement of Indian Patent No. 262697, titled “Acylated GLP-1 Analogs Comprising Non-Proteogenic Amino Acid Residue”. The patentee, Novo Nordisk, also filed an application for an interim injunction.
In response, Dr. Reddy’s challenged the patent’s validity, and filed a countersuit for revocation under Section 64 of the Act, citing several grounds, including:
- anticipation by prior claiming under Section 64(1)(a);
- lack of novelty due to prior publication under Section 64(1)(e); and
- obviousness or lack of inventive step under Section 64(1)(f).
The entire case revolves around the compound Semaglutide which was specifically claimed in Claim 23 of the patent. Novo Nordisk alleged that Dr. Reddy’s was importing and exporting Semaglutide, resulting in infringement of its patent.
Dr. Reddy’s argued that Semaglutide differed only marginally from compounds disclosed in an earlier patent, IN 275964, also held by Novo Nordisk (the genus patent). It said that the only difference was the replacement of the amino acid alanine (Ala) with α-aminoisobutyric acid (Aib) at the 8th position in the peptide sequence. However, the genus patent indicated that the amino acid at the 8th position could be selected from a group that included Aib.
Single Judge decision
The Single Judge of the Delhi High Court, which first heard the matter, refused an interim injunction, holding that the defendant had raised a credible challenge to validity under:
- Section 64(1)(a) – Anticipation by Prior Claiming,
- Section 64(1)(e) – Novelty, and
- Section 64(1)(f) – Obviousness
Division Bench decision
The matter was then appealed and heard by a Division Bench (“DB”) of the same Court. The DB, while accepting that a credible challenge had been raised, did not agree with the entire reasoning of the Single Judge. The DB agreed that Semaglutide is obvious to a person skilled in the art in light of the complete specification and teachings of the genus patent, thereby rendering the patent vulnerable under Section 64(1)(f) (obviousness). But, it did not agree with the Single Judge’s application of these facts to Section 64(1)(a) (anticipation by prior claiming).
The DB provided critical guidance on the various grounds discussed in the matter:
- Anticipation by Prior Claiming: Section 64(1)(a)
- This is a narrow and rigid test. It applies only where the invention claimed in the suit patent has been claimed in a valid claim of a granted Indian patent having an earlier priority date than the suit patent. The statutory provision (Section 64(1)(a)) uses ONLY the terms “claim” and “claimed”, and NOT the terms “disclosure”, “coverage”, “obviousness”, “newness”, or “novelty”. The use / omission of these terms, being obviously deliberate, legislative intent must be respected accordingly.
- The expression “the invention, so far as claimed in any claim”, means that it is not the invention itself, but the extent to which the invention is claimed in the claim of the suit patent, that Therefore, Section 64(1)(a) would apply only where the claim in the suit patent is identically claimed in an earlier granted patent.
- Identity of claims in the suit patent and the prior art is, therefore, the sine qua non for Section 64(1)(a) to apply.
- In the present dispute, the DB concluded that the claims of the earlier genus patent did not identically claim the Semaglutide compound. Therefore, the challenge could not strictly succeed under Section 64(1)(a).
- Obviousness: Section 64(1)(f)
- The legal position regarding “obviousness” is well settled. “Obviousness” requires examining whether a “person skilled in the art” would, from the teachings in prior art, in conjunction with their existing prior knowledge, be able to arrive at the invention claimed in the later patent. If the person can, the claim in the later patent is “obvious” from prior art, and would, therefore, not be patentable.
- On the other hand, the presumption of obviousness can be dispelled by establishing that, in transitioning from the teachings in prior art to the claim in the later patent, an inventive step is involved.
- The five-step test proposed in Hoffmann-La Roche Ltd. v. Cipla Ltd (2016) 65 PTC 1 (DB) could be a litmus test for obviousness, this test need not be applied at the interim stage. Instead, at the interim stage, the court need only satisfy itself that prima facie a credible challenge to the validity of claims of the suit patent has been raised in view of the prior art. To this extent, the judge should don the mantle of the “person skilled in the art”, and examine the issue from such a perspective.
- In the present dispute, the DB noted that the earlier genus patent disclosed:
- the relevant GLP-1 analogue structure, and
- the possibility of substituting the amino acid at the 8th position with alternatives including Aib.
- Accordingly, the DB held that a skilled person could substitute Ala with Aib in the compound disclosed in the genus patent and thereby obtain Semaglutide. Thus, while the earlier patent did not explicitly claim Semaglutide, it provided sufficient guidance for a skilled person to arrive at it. This made the invention prima facie
- The “Person in the Know” Perspective:Another notable issue was the DB’s reliance on the “person in the know” approach, as five inventors were common to both the genus patent (IN’964) and the suit patent. By applying this standard, the Court could assess obviousness from the perspective of a person already familiar with the development of the invention, rather than a notional person skilled in the art. From this perspective, the Court found it even more likely that the modification leading to Semaglutide would have been obvious.
Outcome
Holding that the defendant had established a credible challenge to the validity of the patent on the ground of obviousness, the DB dismissed the appeal.
Key takeaways
The decision clarifies that anticipation and obviousness are distinct doctrines and must be analysed separately. Anticipation by prior claiming requires identity of claims, not merely similarity of disclosure.
Separately, this decision notes that the standard for the “person skilled in the art” is less strict at the interim stage: five-step test proposed in F. Hoffmann-La Roche Ltd. v. Cipla Ltd (2016) 65 PTC 1 (DB) for determining obviousness need not be applied at the interim stage. Instead, the judge should don the mantle of the “person skilled in the art” and examine the issue from that perspective.
Finally, the decision highlights that where inventors are common to the suit patent and the prior patent, the “person in the know” standard may apply, under which obviousness is assessed from the perspective of a person already familiar with the development of the invention, rather than a notional person skilled in the art.
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