The Test of "The Test of Person in the Know" in Patent Infringement
Introduction: In this case Imagine a drug company holding a patent on a blockbuster diabetes medicine that is due to expire in just two months. It rushes to court asking for an order to stop a generic competitor from selling the same drug. The lower court says no because the patent looks weak. The company appeals. The High Court listens, but then asks a blunt question: why should we spend court time on a case that will become pointless the moment the patent dies? This is exactly what happened in the fight between Novo Nordisk and Dr. Reddy’s Laboratories over the patent for Semaglutide.
The Division Bench of the Delhi High Court dismissed the appeal on 9 March 2026, agreeing that the patent was open to a strong challenge because the invention was obvious from an earlier patent. The story is not just about one drug; it tells how Indian courts balance patent protection, public interest and the limited life of every patent.
Factual Background:Novo Nordisk owns Indian Patent No. 262697 (IN’697), granted for “Acylated GLP-1 Analogs Comprising Non-Proteogenic Amino Acid Residue”. The patent claims Semaglutide as one of its specific compounds (Claim 23). The priority date is 18 March 2005. Semaglutide is a once-weekly injection or tablet used to treat type-2 diabetes and obesity. Novo sells it in India under the brand names Wegovy and Rybelsus. In December 2024 Novo learned that Dr. Reddy’s was importing and exporting Semaglutide. Novo believed this infringed its patent. It sent a cease-and-desist notice in May 2025. When Dr. Reddy’s did not stop, Novo filed a commercial suit in May 2025 asking the court to stop Dr. Reddy’s from making or selling the drug and also sought an immediate temporary order (interlocutory injunction) to protect its rights until the full trial.
Procedural Background:The single judge of the Intellectual Property Division heard the injunction application and rejected it on 2 December 2025 after a detailed order. She found that Dr. Reddy’s had raised a credible challenge to the validity of Novo’s patent. Novo filed an appeal before the Division Bench (FAO(OS)(COMM) 204/2025). By the time the appeal was argued and judgment reserved, only about two months remained before the patent would expire on 20 March 2026. The Division Bench reserved judgment on 19 January 2026 and delivered it on 9 March 2026.
Reasoning:The Division Bench began with some strong prefatory thoughts. The judges openly wondered whether they should even spend precious court time on a patent that was about to die. They noted that after 20 March 2026 anyone could make Semaglutide. There was no allegation that Dr. Reddy’s was selling sub-standard medicine. They asked what real harm Novo would suffer in the last two months. Still, because the matter had already been argued, the judges decided they must give a judgment. They made clear they would not re-try the entire case from scratch; they would only check whether the single judge had made any basic legal error (following the famous Wander Ltd principle).
The judges then explained the law in simple terms.
A patent can be challenged on several grounds listed in Section 64 of the Patents Act. The most important for this case were prior claiming (Section 64(1)(a)), lack of novelty (Section 64(1)(e)) and obviousness (Section 64(1)(f)). At the stage of a temporary injunction the defendant does not have to prove the patent is definitely invalid; it only has to show a “credible challenge”. If such a challenge exists, the court usually refuses to stop the defendant until the full trial.
The court carefully compared Novo’s patent (IN’697) with an earlier patent owned by Novo itself – Indian Patent IN’964 (the “Genus Patent”). IN’964 covered a broad family of GLP-1 compounds and specifically described a compound called Example 61 (Ala Semaglutide). The only difference between that compound and the Semaglutide claimed in IN’697 was the replacement of one amino acid (Ala) with another (Aib) at position 8.
The single judge had treated this as prior claiming under Section 64(1)(a). The Division Bench disagreed on that exact legal label. Section 64(1)(a) needs the claims to be identical; it is a strict claim-to-claim match. Here the claims were not exactly the same. However, the judges said the single judge’s detailed analysis actually proved something even stronger – that Semaglutide was obvious to a skilled person from the teachings of IN’964. That made the patent vulnerable under Section 64(1)(f).
The court added an important new point. Five inventors were common to both patents. In such cases earlier Division Bench decisions (AstraZeneca AB v Intas and F Hoffmann-La Roche v Natco) say the court should use the stricter “person in the know” test instead of the ordinary “person skilled in the art”. Because the inventors themselves knew the earlier patent inside out, it was even easier for them (or someone like them) to see that changing Ala to Aib would give Semaglutide. The Supreme Court had refused to interfere with those earlier rulings, so the test is now settled law. The judges found that even under this tougher test a credible challenge of obviousness existed.
The Division Bench also looked at the urgency issue again. It said that directing Dr. Reddy’s to keep accounts of sales for the last two months would have been enough protection. There was no need to stop sales completely when the patent was dying anyway.
Judgements with complete citation and their context discussed:The court relied on several key decisions and explained them in easy language. First came Wander Ltd v Antox (India) Pvt Ltd (1990 Supp SCC 727). This Supreme Court case says that in appeals against temporary injunction orders the higher court should not replace the lower court’s view with its own unless the lower court made a clear legal mistake. The Division Bench said it was bound by this rule and would only check for error of principle.
Next the court discussed the two Roche cases – F Hoffmann-La Roche Ltd v Cipla Ltd (Roche-I) (2009) 159 DLT 243 (DB) and the later Roche-II (2016) 65 PTC 1 (DB). These explain what a “credible challenge” means and lay down the five-step test for deciding obviousness. The Division Bench praised the single judge for following those steps but gently noted that at the injunction stage a full five-step mini-trial is not needed; the judge can simply put himself in the shoes of the skilled person and see whether the invention looks obvious.
The court also referred to Novartis AG v Union of India (2013) 6 SCC 1 (the famous Glivec case) while discussing genus versus species patents. It explained that when a broad patent already teaches a specific compound, a later narrow patent cannot claim the same thing again.
Importantly the judges cited their own earlier Division Bench rulings – AstraZeneca AB v Intas Pharmaceuticals Ltd (2021 SCC OnLine Del 3746) and F Hoffmann-La Roche AG v Natco Pharma Limited (2025 SCC OnLine Del 6390). These introduced the “person in the know” test when inventors overlap. Both judgments have been upheld by the Supreme Court (SLPs dismissed). The court said this test applies here because the same inventors filed both patents.
Finally the court mentioned Pernod Ricard v Karanveer Singh Chhabra (2025 SCC OnLine SC 1701) to repeat that appellate courts must be slow to interfere with discretionary injunction orders.
The Final Decision of Court: The Division Bench dismissed the appeal in its entirety. It held that the single judge’s order refusing the injunction was correct. The patent was prima facie vulnerable to revocation on the ground of obviousness under Section 64(1)(f) because of the earlier genus patent IN’964. The court made clear that everything said in the judgment was only a prima facie view and would not bind the single judge when the full trial takes place later.
Introduction
This is a detailed Division Bench judgment dated 9 March 2026 of the High Court of Delhi (Coram: Hon’ble Mr. Justice C. Hari Shankar and Hon’ble Mr. Justice Om Prakash Shukla) in FAO(OS)(COMM) 204/2025, arising from an intellectual property (patent) dispute. The appellant, Novo Nordisk A/S, challenged the learned Single Judge’s order dated 2 December 2025 rejecting its application for an interlocutory (temporary) injunction under Order XXXIX of the Code of Civil Procedure, 1908, in a patent infringement suit CS(Comm) No. 565/2025. The suit patent is Indian Patent No. 262697 (“IN’697” or “suit patent”) titled “ACYLATED GLP-1 ANALOGS COMPRISING NON-PROTEOGENIC AMINO ACID RESIDUE”, with priority date 18 March 2005. It specifically claims Semaglutide (Claim 23) — the active pharmaceutical ingredient in the appellant’s anti-diabetic drugs Wegovy and Rybelsus. The respondents (Dr. Reddy’s Laboratories Ltd. & Anr.) were alleged to be importing and exporting Semaglutide, thereby infringing the suit patent.
The judgment is remarkable for two reasons. First, it contains extensive “prefatory thoughts” (paras 1–12) questioning the propriety of entertaining an appeal when the suit patent was set to expire on 20 March 2026 (i.e., barely two months after arguments and judgment reservation). The Bench pondered issues of judicial economy, balance of convenience, irreparable loss, and the larger public interest in prioritising cases affecting the poor over “pedestrian” commercial patent appeals with no real urgency. Second, on merits, the Bench upheld the Single Judge’s refusal of injunction after finding a “credible challenge” to the validity of the suit patent under Section 64(1)(f) of the Patents Act, 1970 (obviousness/lack of inventive step) from the prior genus patent IN 275964 (“IN’964”). It slightly differed from the Single Judge on the applicability of Section 64(1)(a) (anticipation by prior claiming) but held that any single ground under Section 64 suffices as a defence under Section 107(1). The observations are expressly prima facie only and will not bind the trial on merits.
Factual Background
Novo Nordisk holds the suit patent IN’697 granted in India, which covers acylated GLP-1 (glucagon-like peptide-1) analogues containing non-proteogenic amino acid residues. Semaglutide is specifically claimed in Claim 23 and is a once-weekly injectable anti-diabetic (Type-2 diabetes) and anti-obesity drug. The appellant became aware in December 2024 that Dr. Reddy’s was importing and exporting Semaglutide, which it alleged infringed IN’697. On 5 May 2025, Novo issued a cease-and-desist notice. No response was received, leading to the filing of the suit on 26 May 2025. Dr. Reddy’s did not deny the acts of importation/export (and thus stricto sensu infringement) but raised a defence under Section 107(1) that the suit patent was vulnerable to revocation on multiple grounds under Section 64(1), primarily (a), (e), and (f), based on the earlier Indian genus patent IN’964 (priority earlier than IN’697). IN’964 claims a broader class (Markush structure) of GLP-1 analogues, including an exemplified compound (Example 61 / Claim 21) that is identical to Semaglutide except for the substitution of alanine (Ala) with α-aminoisobutyric acid (Aib) at position 8. Five inventors are common to both patents.
Procedural Background
The suit was accompanied by an application for interim injunction restraining manufacture, use, sale, or import of Semaglutide. By order dated 29 May 2025, the respondents gave an undertaking not to sell in India pending hearing. The injunction application was finally heard and rejected by the learned Single Judge on 2 December 2025 after a detailed, well-reasoned order analysing Sections 64(1)(a), (e), and (f). Novo preferred the present appeal. Arguments were heard and judgment reserved on 19 January 2026 — at which point only about two months remained for the patent to expire on 20 March 2026. The Division Bench delivered the judgment on 9 March 2026. The appeal was dismissed, affirming the Single Judge’s order.
Dispute in Question
The core dispute was whether the appellant was entitled to an interlocutory injunction pending trial. Legally, this required the appellant to satisfy the three-pronged test under Order XXXIX Rules 1 & 2 CPC: (i) prima facie case, (ii) balance of convenience, and (iii) irreparable loss. Because the respondents raised a defence under Section 107(1) read with Section 64, the Single Judge (and now the Division Bench) had to examine whether the respondents had set up a “credible challenge” to the validity of IN’697. At the interim stage, the defendant need only show vulnerability to revocation on any ground in Section 64; the court does not decide validity on merits (that is reserved for trial after evidence). The Division Bench further restricted its appellate review to the Wander standard (appeal against discretion is only on principle; interference only if the Single Judge acted arbitrarily, capriciously, or ignored settled law).
Arguments of Parties
Appellant (Novo Nordisk):
Clear infringement admitted by respondents.
Suit patent valid; Semaglutide not claimed or enabled in IN’964. Only two specific compounds claimed in IN’964 (Claims 18 and 21); Semaglutide is a distinct species with Aib (non-proteogenic) at position 8.
No enabling disclosure or claim-to-claim identity under Section 64(1)(a).
Not obvious under Section 64(1)(f); requires inventive step (technical advance + non-obviousness to person skilled in the art — PSA).
Balance of convenience and irreparable loss favour injunction; respondents not manufacturing sub-standard drugs, but patent rights must be protected to incentivise innovation.
Respondents (Dr. Reddy’s):
Admitted acts of importation/export but invoked Section 107(1) defence.
Credible challenge under:
Section 64(1)(a) — anticipation by prior claiming in IN’964 (genus covers Semaglutide via enabling disclosure and preferred substitution).
Section 64(1)(e) — lack of novelty (anticipated by publication of IN’964).
Section 64(1)(f) — obviousness (PSA would arrive at Semaglutide from IN’964 teachings, especially Claim 1 + dependent Claim 16 preferring Aib at position 8, plus Example 61).
Admissions by Novo in foreign jurisdictions and before Indian Patent Office that Semaglutide is the only commercial product from both patents.
No urgency for injunction given imminent expiry; accounts would suffice.
Reasoning of Judge (Including Different Provisions of Law and Their Context)
The Division Bench began with “prefatory thoughts” (paras 1–12) on judicial economy: when only two months remained for expiry, no sub-standard drug allegation, and no irreparable loss post-expiry (patent enters public domain), the appeal should perhaps be dismissed on balance of convenience and irreparable loss de hors merits. Courts are overburdened; time spent on such matters delays justice for the poor. However, having heard the matter, they proceeded to decide on merits strictly within Wander confines (no de novo re-appreciation).
Key Statutory Provisions (Patents Act, 1970) and Their Context
Section 48 (Rights of patentees): Grants exclusive right to prevent third parties (without consent) from making, using, offering for sale, selling, or importing the patented product (or using the process). This defines infringement. Context: negative right to exclude, not a positive right to exploit.
Section 64(1) (Revocation grounds): Non-exhaustive list; patent “may” be revoked on any ground. Each clause is independent. Relevant here:
(a) Anticipation by prior claiming: Invention “so far as claimed in any claim” of the suit patent was claimed in a valid claim of earlier priority Indian patent. Requires identity of claims (claim-to-claim comparison). No role for “person skilled in the art” (PSA), disclosure, or obviousness. Legislature deliberately used “claimed” (not “disclosed” or “covered”). Fortified by Section 13(1)(b) (examiner’s duty — claim-to-claim).
(e) Lack of novelty (not new): Invention not new having regard to prior public knowledge/use in India or publication (anticipation by prior publication — Sections 13(1)(a) & 13(2)). “Anticipation” dovetails into novelty; exact disclosure enabling PSA to arrive at invention without undue experimentation.
(f) Obviousness / lack of inventive step: Invention obvious or does not involve inventive step having regard to prior art. Defined via Section 2(ja): feature involving technical advance or economic significance (or both) making it non-obvious to PSA.
Section 107(1) (Defences in infringement suit): Every Section 64 ground is available as defence. At Order XXXIX stage, defendant needs only “credible challenge” (vulnerability) — not proof of invalidity (F. Hoffmann-La Roche Ltd. v. Cipla Ltd. — “Roche-I”, 2009).
Section 2(ja) (Inventive step): Statutory definition of non-obviousness.
The Bench clarified that Section 64(1)(a) is narrow (pure claim identity); Sections (e) and (f) involve PSA perspective.
Judgements Including Their Citation and Context Relied by Judge in Reasoning
Wander Ltd. v. Antox (India) Pvt. Ltd. (1990 Supp SCC 727): Core appellate standard. Appeals against discretion are “appeals on principle”. Appellate court does not re-assess material or substitute view unless Single Judge acted arbitrarily, capriciously, perversely, or ignored settled principles. Reiterated in Pernod Ricard v. Karanveer Singh Chhabra (2025 SCC OnLine SC 1701). Context: limits interference in Order XXXIX patent appeals.
F. Hoffmann-La Roche Ltd. v. Cipla Ltd. (Roche-I, 2009) — para 55 quoted verbatim: Classic exposition of “credible challenge” at interim stage. Defendant need only show patent “vulnerable”; court enquires if challenge raises serious triable issue. Applies Section 3(d) + Section 64 scrutiny for pharma patents. “Legally fossilized” standard.
F. Hoffmann-La Roche Ltd. v. Cipla Ltd. (Roche-II, 2012) 65 PTC 1 (DB): Five-step test for obviousness: (1) identify PSA; (2) inventive concept; (3) common general knowledge; (4) differences vs. prior art; (5) whether differences obvious (no hindsight). Bench here holds these steps ideal for final adjudication (after evidence) but impractical for Order XXXIX; judge may “don the mantle” of PSA for prima facie view. Cautions against mini-trial (Brihan Karan Sugar Syndicate (P) Ltd. v. Yashwantrao Mohite Krushna Sahakari Sakhar Karkhana, 2024 2 SCC 577).
Novartis AG v. Union of India (2013) 6 SCC 1 & Novartis AG v. Natco Pharma Ltd. (2023 SCC OnLine Del 106): Genus vs. species patents; species claim vulnerable if derived from genus teachings + enabling disclosure (especially Markush structures). Single Judge relied heavily; Division Bench says this reasoning actually proves obviousness (f), not prior claiming (a).
AstraZeneca AB v. Intas Pharmaceuticals Ltd. (2021 SCC OnLine Del 3746) & F. Hoffmann-La Roche AG v. Natco Pharma Limited (2025 SCC OnLine Del 6390): “Person in the know” test (higher than PSA) when inventors common. SLPs dismissed by Supreme Court — Apical affirmation. Applied here because five common inventors; obviousness viewed from “person in the know”.
Final Decision
Appeal dismissed. Impugned order (refusal of injunction) upheld. Semaglutide is prima facie obvious to a person skilled in the art (or “person in the know”) from IN’964 (Claim 1 + dependent Claim 16 preferring Aib at position 8 + Example 61 / Claim 21). Credible challenge under Section 64(1)(f) made out; hence Section 107 defence succeeds. No case for interference under Wander. Observations prima facie only.
Concluding Note
The Bench balanced strong public-interest concerns (judicial time, patent expiry, incentivising innovation) with strict adherence to law. It refused to grant even two months’ injunction, suggesting accounts as sufficient safeguard. The judgment underscores that interim relief in patent cases is not automatic even on admitted infringement if validity is credibly challenged.
Legal Point Settled in This Case
At the Order XXXIX stage in a patent infringement suit:
A “credible challenge” under any clause of Section 64(1) (via Section 107(1)) defeats injunction if it shows vulnerability.
Section 64(1)(a) requires exact claim-to-claim identity; enabling disclosure or obviousness belongs to Sections 64(1)(e)/(f). PSA has no role under (a).
For obviousness under Section 64(1)(f), while Roche-II’s five steps are authoritative for final trial, at interim stage the court may adopt a pragmatic PSA (or “person in the know” where inventors overlap) perspective without mini-trial.
Common inventors elevate the obviousness test to “person in the know”.
Imminent patent expiry + no urgency/irreparable loss can justify refusal of injunction on balance of convenience de hors merits (though here decided on merits).
Case Title: Novo Nordisk Vs Dr.Reddy Laboratories Limited and another
Date of Order: 9 March 2026
Case Number: FAO(OS) (COMM) 204/2025
Neutral Citation: 2026:DHC:1911-DB
Name of Court: High Court of Delhi
Name of Hon’ble Judges: Hon’ble Mr. Justice C. Hari Shankar and Hon’ble Mr. Justice Om Prakash Shukla
Disclaimer: Readers are advised not to treat this as substitute for legal advise as it may contain errors in perception, interpretation, and presentation
Written By: Advocate Ajay Amitabh Suman, IP Adjutor [Patent and Trademark Attorney], High Court of Delhi
Headnote of article:
Delhi High Court dismisses Novo Nordisk’s appeal against refusal of interim injunction in Semaglutide patent suit; holds that the patent (IN’697) is prima facie obvious under Section 64(1)(f) from earlier genus patent IN’964; clarifies distinction between prior claiming and obviousness; applies “person in the know” test due to common inventors; reiterates Wander standard and notes limited utility of injunction when patent expires in two months.
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