In Intra Cellular Therapies v. Controller of Patents, the Delhi High Court revisited two recurring fault lines in pharmaceutical patent law: the coverage disclosure distinction in genus-species claims and the therapeutic efficacy threshold under Section 3(d). Arnav Kaman argues that while the Court gets parts of the Section 3(d) analysis right, its treatment of coverage as disclosure, its failure to meaningfully engage with the applicable novelty standard, and its silence on inventive step leave the judgment doctrinally unclear and the law more unsettled than before. Arnav is a 5th-year law student from Rajiv Gandhi National University of Law, Punjab. He’s interested in Narratives and the Law.
One Atomic Substitution, Two Giant Hurdles of Disclosure and Efficacy
By Arnav Kaman
In the recent case of Intra Cellular Therapies v Controller of Patents, the DHC upheld the rejection of a patent application for claims of deuterated chemical compounds, finding a lack of novelty and non-patentability under Section 3(d). The Court, upholding the patent office’s rejection, opined on two of the most contested disputes in pharmaceutical patenting– the Coverage-Disclosure Distinction and Therapeutic Efficacy under Section 3(d). Faced with such challenging territories of patent jurisprudence, the judgement dives in headfirst; it errs in some instances, lacks doctrinal clarity, triumphs in others, and completely disregards some questions, leaving the field more perplexed than before.
Background
The present patent application titled “Organic Compounds” pertains to claims for chemical compounds which have a proposed application in the treatment of diseases like anxiety, psychosis, schizophrenia, sleep disorders etc. The Applicants are also the patentees of IN 451581, which is a set of Markush Claims, a broad set of claims covering a large family of possible compounds, over the family of compounds that this present application is a species of. This present application is specifically on the basis of the deuterated set of these compounds. Deuteration is a chemical process wherein a number of the hydrogen atoms of a chemical compound are replaced with deuterium atoms, which are a heavier and stable isotope of hydrogen.
The Patent Office rejected the application on the basis of three grounds: lack of novelty and inventive step along with non-patentability under 3(d). The Court, however, notably, does not delve into the question of inventive step and upholds the rejection on the basis of the lack of novelty and Section 3(d).
Another Stab at the Genus-Species Coverage Disclosure Debate
The Patent Bargain imagines that when an inventor has invented a new invention, they disclose their teachings to the public, and in exchange, the state grants an exclusive right to the inventor to restrict others from making it. Yogesh, in this post, accurately puts it: “Coverage” refers to the claims in a patent that decide the scope of Infringement, whereas “Disclosure” refers to the teachings in the patent that enable a person skilled in the art to reproduce it and decides the anticipation of an invention. Indian courts, however, have taken the view that there must not be a vast gap between coverage and disclosure, as held in Novartis AG v UOI. This distinction gets further aggravated in a Markush claim, wherein a genus claim may cover multiple species but does not specifically disclose each and every compound. The coverage-disclosure dispute has become a matter of great consternation amongst the patent fraternity and has been covered on the blog here, here, and here.
In the present case, since the applicants are the patentees of the genus patent, the question in case of deciding novelty is simple: “Does the Genus Patent (IN 451581) disclose the Species Patent (Present Application)?”
The Patent Office considered D1 and D7, PCT Applications of the genus and by examining the claims of the patent, found that certain embodiments did in fact mention how certain elements could be substituted for deuterium. Operatively, the Prior Art, being Markush claims, does not explicitly disclose the entirety of the present claimed compounds, but only certain selections in certain instances, which the patent office infers to be enough to arrive at the claimed compound. It is this particular nature of Markush claims that the appellants use to bolster their counter. They state the claims only disclosed the broadest representation of the compound in a general manner, and multiple selections would be necessary to arrive at the presently claimed compounds. Furthermore, the Patent Office did not prove as to how the skilled person would be motivated to make such selections.
The Court, re-examining the prior art, reproduces the Patent Office’s analysis and succinctly holds that the claims of the patent application do in fact disclose the present compound. The Court states that “ it is a settled position that where a compound is disclosed under the genus patent, specific disclosure is immaterial.” (Para 63 of the Judgement) The Court makes quite a logical leap here, which is not explicitly articulated, but one I have attempted to untangle and scrutinise:
Firstly, the Court has taken the position that the coverage of the claims themselves amounts to disclosure. This, in itself, is problematic in patent law, since, in the case of Markush claims wherein not all the species are disclosed (mind you that there may be millions of species!), the patent coverage of the claims may conceivably be larger than its disclosure. Furthermore, claims alone may not be enough to teach a Person Ordinarily Skilled in the Art (POSITA) to reproduce the compound.
Secondly, the position taken by the DHC in AstraZeneca (2023) and Boehringer (2023), which are both cited, supports the proposition that when a product is specifically covered by the claims, the disclosure is immaterial. Whether one agrees with the proposition or not, it’s necessary to note that both cases deal with infringement and state that, if there is coverage, there is no need for specific disclosure, not if there is general disclosure and specific disclosure.
Thirdly, the Court cites Novartis AG, in an attempt to equate Coverage and Disclosure to one another, to make the final link, yet Novartis does not anywhere state that the two are the same concept or that they should be synonymous with one another.
Beyond the Court’s entanglement, the law is not quite settled, as they put it. The Guidelines for Examination of Patent Applications in the Field of Pharmaceuticals, while not binding but an interpretative aid, clearly state “A generic disclosure in the prior art may not necessarily take away the novelty of a specific disclosure.” In fact, the DHC in FMC Corporation v Best Crop (2021) explicitly says mere coverage does not amount to disclosure, and it would be a question for the Court to examine whether the species patent was obvious from the genus patent.
Even in a Markush, not all atomic substitutions and selections may be so immediately obvious and would require specific disclosure for it to be anticipated. It is for this specific purpose that patent law has developed the tests of POSITA while considering Novelty. In fact, in the case of a Genus-Specie patent where the applicants are the same, DHC in Roche v Natco (2025) has held that a higher standard of the Person in the Know must be used for determining novelty. The question the Court should have examined is simple: Could a PIK have anticipated the species from the disclosure of the genus? Instead of answering this question, the Court sets it aside with a statement on specific disclosures being immaterial, omits to examine inventive step, and has left a central part of this application unanswered.
Not Enough Evidence for Efficacy
The Patent Office rejection has little analysis on non-patentability, aside from one paragraph, and the Appellants correctly point out that for the application of Section 3(d), firstly the known substance itself must be first identified before a comparison with the new form. Furthermore, the Appellant provided in vivo experimental data of the deuterated compounds, in comparison to the non-deuterated compounds, which they allege portray significant pharmacokinetic improvements and increased bioavailability.
The Court, considering Section 3(d), states that compound Q (the non-deuterated compound) disclosed in the Prior Art would be the “known substance” and the compounds in the present application would be the new forms of a known substance. Such a new form would only cross the bar of patentability of Section 3(d) if the new form can demonstrate significant therapeutic efficacy in the case of a medicinal drug.
While the Court notes that, from the evidence submitted by the Appellants, the deuterated compound left more intact drug in the blood, it also notes that bioavailability, in itself, does not imply an enhancement of therapeutic efficacy as held in Novartis. Such a claim would need to be independently analysed and supported by evidence. The Appellant’s evidence demonstrated the similarity in the pharmacological activity of the two compounds, but not necessarily how it may treat the disease itself better.
[As a side note: while analysing 3(d) the Court extracts sections from Novartis v Natco (Delhi High Court 2024), which the SC has explicitly set aside, stating they should not be cited as precedent. Admittedly, they may still be instructive for reasoning, but such a qualifier would be relevant when citing the judgements.]
The Court continues to enforce the higher standard established by 3(d) correctly, yet, as in many other instances fails to opine as to what exactly the data required might look like to connect bioavailability to therapeutic efficacy.
Missing Gap: Inventive Step
The Patent Office’s rejection of the application covers Inventive step with a single paragraph stating that by examining the papers cited about deuteration and the previous patent applications, it would be obvious for a person skilled in the art to bring a ‘deuterated alternative of known drugs. This is far too thin an explanation to justify a rejection, enough so that the Court should have at least re-examined it. Yes, deuteration is a known phenomenon, but the specific deuteration in those particular instances may not have been obvious and may have required selection, as argued by the appellant. Yet, even though the Court had the opportunity, this central inquiry remains unsubstantiated.
India’s attempts at bridging the gap between coverage and disclosure and the higher standard for therapeutic efficacy are both attempts to prevent evergreening of patents, especially for pharmaceutical patents. Yet, a patent system that has unclear standards and tests is bound to result in bad outcomes for all stakeholders in the business. When courts are unwilling to delve into certain questions of law and rigid on others, we enter into confusing territories for questions that are central to a patent regime.
(All errors are attributable to the Author, who welcomes being corrected, especially with regard to any errors made in the post regarding claims of chemistry. The Author would also like to thank Praharsh for his comments.)
