On the recent Risdiplam judgement by a DB of the Delhi High Court, Dr. Victor Vaibhav Tandon takes a look at some of the crucial observations of the Court and writes on the resurrection of the disclosure-coverage conundrum, and the person in the know standard for assessing obviousness. In this two part post, Part I will deal with the Court’s observations on coverage- disclosure conundrum and where it fits in the age old discussion taking place on the issue within India. Part II of the post will discuss the ‘Person in the Know’ standard for inventive step assessment and public interest. Dr. Tandon is an academician turned lawyer, with the law firm Saikrishna and Associates. He continues to teach patent law- rather sporadically- at ILI and ISIL. The views expressed herein are strictly personal. He was not involved in any of the cited matters in any manner, except the FMC CTPR disputes one of which is cited in the judgment. Alternative views and corrections, if any, are welcome. His previous posts can be accessed here.
Part I: Genus-Specie Disputes: Thoughts on the Risdiplam Division Bench Judgment
By Dr. Victor Vaibhav Tandon
This piece attempts to contextualize the Risdiplam judgment within the ever-evolving Indian genus-species jurisprudence.
The Gospel of Genus-Species: An Origin Story
In the beginning, there was a Markush patent and in that Markush patent lay the clues to a compound. Some would say the clues to the compound were as good as hiding a leaf in the forest. And that compound in the Markush patent (or as the patentees would tell you, only the clues thereof) led to a specie patent. And then there was an eternal jurisprudential dilemma, known as the genus-species conundrum.
A Preface
As far as eternal dilemmas go, the last time I wrote about genus-species disputes, an anonymous intelligence chided me rather severely because apparently this was an area of law that was well-settled. I wish that were so, and I wouldn’t be having so many questions every time a judgment in this domain came about. But then, since my limited intelligence is neither artificial nor anonymous, here we go again (as I said the last time around, that sense of déjà vu). Readers may like to read my previous post for a sense of continuity and context.
The Risdiplam Judgment
On 09th October 2025, a division bench of the Delhi High Court handed down its judgment in an interim injunction application concerning a patent for the product Risdiplam, a drug used for the treatment of Spinal Muscular Atrophy (Risdiplam DB).
Since the time of the judgment in AstraZeneca v. Intas relating to the drug Dapagliflozin (Dapa DB), the Risdiplam judgment is arguably an important judgment of an appeal bench from the Delhi High Court at the interim stage. In between, there was the ill-fated judgment in Natco v. Novartis relating to the drug Eltrombopag Olamine (Eltrombopag DB). Ill-fated because the Supreme Court by its 02 August 2024 order ended up setting aside both the single judge judgment and the division bench judgment, rendering both sans any precedential value since the patent had expired while the appeal was being heard by the Division Bench. Of course, the apex Court never settled the issue in Eltrombopag dispute. When parties settle or the patent expires, the law remains unsettled.
The Risdiplam DB affirmed the decision of a single judge to deny interim injunction in respect of patent IN 334397 since the said patent was demonstrably obvious from WO’916/US’955, and thus a credible challenge was duly raised. Crucially, the appeal bench said that it was not “inclined to hold that a credible challenge… stands made out on basis of the claims/disclosures contained in the genus patent documents WO’916/US’955” and that whether, in this context Dapa DB is correctly decided “may have to be examined in another, more appropriate case”. The Risdiplam DB did agree with Dapa DB on another aspect though, that of ‘person in the know’ in context of genus-specie disputes, a rather radical approach to inventive step analysis. This aspect is discussed later.
Pertinently, the appeal bench in Risdiplam was concerned with two broad issues,
- was the invention of the suit patent not new, thus being vulnerable to a section 64(1)(e) challenge and
- did the invention of the suit patent lack an inventive step, thus being vulnerable to a section 64(1)(f) challenge?
The Risdiplam DB noted repeatedly that it was going by the Wander parameters and not reassessing the materials to supplant its own reasoning for that of the single judge. Therefore, as long as the single judge had applied the principles of law correctly, the appeal bench would not interfere even if it was of the view “that an alternative conclusion could more preferably be arrived at”.
Coverage-Disclosure Dichotomy
In the context of Eltrombopag DB, I had earlier written that,
“[Eltrombopag] DB held that there cannot be a gap between coverage and disclosure- an argument done to death by patentees, who have consistently argued that Novartis I did allow for some gap and only disallowed a “vast gap” between coverage and disclosure…held that there cannot be such a dichotomy and such dichotomy would negate the fundamental rule underlying the grant of patents”.
Since the Eltrombopag DB is not precedential anymore, the patentees in Risdiplam dispute again argued that coverage of the specie compound within the Markush/ genus patent does not amount to disclosure since there is no sufficient teaching in the genus patent that would lead a skilled person to make the transition from the genus patent to the skilled patent.
While the single judge in the Risdiplam dispute relied on Novartis v. Union of India and rejected this submission, the appeal bench noted that “there are diverse views of this Court. The manner in which the judgment of the Supreme Court in Novartis AG has been interpreted by different benches of this Court, too, do not exhibit uniformity of thought. One of us…, sitting singly, has, in FMC Corporation v. Best Crop Science LLP, adopted the view that that mere coverage of the compound claimed in the species patent within the broad Markush claim in the genus patent would not ipso facto amount to disclosure…”.
The Risdiplam DB then expressed its doubts about the correctness of the principle laid down in Dapa DB, which had proceeded on the premise that “if the product of the defendant is alleged to infringe a genus as well as species patent it would amount to an admission of disclosure, in the genus patent, of the claim in the species patent”. The Risdiplam DB instead noted that, “infringement is predicated on coverage, whereas invalidity is predicated on disclosure”.
That Which is a Yardstick for Infringement, is a Yardstick for Invalidity, or Not?
It is not clear to me (and would be happy to be guided here) why infringement is predicated on coverage but invalidity is predicated on disclosure? Should infringement and validity have different yardsticks? If that is what Risdiplam DB suggests, then is it not running afoul of another DB in Vifor (International) Limited & Anr. v. MSN Laboratories Pvt. Ltd. & Anr.? Vifor DB has said that,
“We fail to discern any logic in recognizing distinct tests of novelty being applicable at the stage of patentability and those that may be relevant for deciding a question of infringement. It is pertinent to observe that both at the stage of grant as well as while considering an allegation of infringement the terms and the language of the claim remain unaltered. Claims and specifications do not change hues but remains static. We thus principally find ourselves unable to countenance the submission that separate or distinct tests of novelty should apply between the grant of a patent and the examination of an allegation of infringement.”
Why would (or should) a reader of a complete specification (which includes claims) read it one way to discern coverage and say, Oh look there is infringement and then read it another way to discern disclosure and then say, Oh look valid/ or not valid?
Remember, infringement is not defined in the Act, as the Risdiplam DB reminds us. And the rights of patentees under Section 48 do not speak of coverage or disclosure, but of subject-matter of the patent. Crucially, Section 53(4) of the Patents Act tells us that once the patent expires, the “subject-matter covered by the said patent shall not be entitled to any protection”. It does not say subject-matter disclosed by the said patent. Section 64(1)(e), under which the novelty challenge was raised in Risdiplam, also does not talk of coverage or disclosure, rather it speaks of “invention so far as claimed in any claim of the complete specification”. How does this sit comfortably with the point that Risdiplam DB notes, that “mere coverage and claiming would not ipso facto result in disclosure”? Of course, the Risdiplam DB appears to proceed on the footing that coverage and disclosure are different things or that there is some gap, if not a vast gap, between them.
A Few What Ifs?
The question here is, what would the Risdiplam DB do if Eltrombopag DB (which had held that there cannot be a gap between coverage and disclosure) was not non-precedential? Referral to a larger bench? Nobody will ever know.
The Risdiplam DB noted that they are not entering into this coverage-disclosure thicket and that the same “may require further consideration”.
Another interesting fact is that in the U.S., Roche (Risdiplam’s patentee) had sued in respect of both the genus and the specie patent. This aspect activated the application of the Dapa DB where both genus and specie patents were asserted by AstraZeneca. If the genus patent had not been asserted simultaneously with the specie patent in the U.S., would Dapa DB be rendered inapplicable to the facts of Risdiplam dispute? Remember, I had noted in my earlier piece that,
“Patentees had consistently sought to distinguish Dapa DB from other genus-species disputes by arguing that AstraZeneca had asserted both genus and species patents therein- and that therefore Dapa DB was factually so different from every other genus-species dispute as to have no applicability to any other genus-species case at all! By such a simplistic strategic tweak, every patentee could avoid the albatross of the Dapa DB from being hung around its neck; until [Eltrombopag] DB had to state the obvious: “the fundamental question involved in both cases is whether a patentee can claim protective rights in respect of the same compound as covered under two product patents: one, a broad claim covering several compounds with an essential core, claiming to possess therapeutic value, and the second a specific claim, in respect of the compound in question”.”
In this case, the patentee of Risdiplam had asserted both genus and species patents in the U.S., so perhaps the occasion did not arise for the Risdiplam DB to determine whether the reasoning of Dapa DB should apply generally to all genus-species disputes. While the single judge in the Risdiplam dispute did note the fact that in the U.S. litigation, both genus and specie patents were asserted, the appeal bench was conscious of the fact that in the India suit, infringement of only the specie patent was claimed (see, para 19.7.2.1).
Part II of the post will discuss the Court’s findings on the ‘Person in the Know’ standard for inventive step assessment and public interest.