Disclosure v. Coverage In Pharmaceutical Patents

The debate over disclosure versus claim coverage in pharmaceutical patents has long been a challenging one especially where a broad generic disclosure (e.g. via a Markush claim) attempts to cover potentially hundreds of millions of compounds on the strength of only a handful of working examples. Patents offer a trade-off: a time-limited monopoly to the innovator in exchange for full public disclosure of the invention so that, post-expiry, the knowledge enters the public domain.

In this context, inadequate disclosure jeopardises the patent's validity, while overly broad coverage leaves the door open for competitors to design around the patent. In pharmaceutical patents, this tension plays out most sharply because compounds are often claimed generically, but only a few representative compounds are synthesized, tested and disclosed with full data. The assumption - inherent to many Markush-style specifications - is that a "person skilled in the art" can, without undue experimentation, synthesize all covered compounds and that these would exhibit similar pharmaceutical activity to the exemplified ones.

This tension was underscored in Novartis AG v. Union of India & Others, decided by the Supreme Court of India in 2013. Though this case dealt primarily with therapeutic efficacy and 'evergreening', it also exposed deeper issues: broad claims supported by minimal disclosure can lead to monopolies without true innovation. Per the court: "We certainly do not wish the law of patent in this country to develop on lines where there may be a vast gap between the coverage and the disclosure under the patent; where the scope of the patent is determined not on the intrinsic worth of the invention but by the artful drafting of its claims by skilful lawyers, and where patents are traded as a commodity not for production and marketing of the patented products but to search for someone who may be sued for infringement of the patent."

Here the court implied that the scope of claim coverage should be commensurate with the working examples provided in the specification and the claimed subject matter should be a reasonable generalisation.

Recent Judicial Developments: Equating Coverage with Disclosure

More recently, some judgments have treated the fact of claim coverage itself as tantamount to disclosure. A striking example is AstraZeneca AB & Anr. v. Intas Pharmaceuticals Ltd. (2021), where the Delhi High Court denied interim injunctions on the ground that the generic (genus) patent already covered the specific drug (species), even though the generic specification did not exemplify or describe that specific molecule. In its order, the court observed that the plaintiffs' own pleadings treated the covered compound as part of the genus patent, implying that a patent holder cannot both claim infringement and simultaneously argue non-disclosure. This effectively collapses the distinction between 'coverage' and 'disclosure' - a shift away from classical patent principles under which a generic disclosure does not destroy the novelty of a species, and a species-specific disclosure remains novel over a generic disclosure.

Such an interpretation has generated a series of directly conflicting precedents. In parallel litigation involving the very same drug - Dapagliflozin - a different single-judge bench in AstraZeneca v. Torrent Pharmaceuticals (2021) reached the opposite conclusion. Here it was held that although the species compound fell within the structural sweep of the genus Markush claim, the genus specification did not specifically disclose it nor provide any enabling teaching to single it out. The species patent was therefore prima facie novel.

A similar divergence has emerged in cases involving Ticagrelor and Linagliptin. One line of cases (AstraZeneca v. Emcure (2020); Boehringer Ingelheim v. MSN (2022)) reaffirmed that mere inclusion within a Markush formula is insufficient to amount to disclosure. Yet companion matters before different benches (AstraZeneca v. Dr. Reddy's Laboratories (2020); Boehringer Ingelheim v. Vee Excel Drugs (2022)) adopted the reverse approach, treating coverage as disclosure and therefore holding the species patents prima facie lacking in novelty.

In fact, in Boehringer Ingelheim Pharma GMBH v. Vee Excel Drugs, while denying interim injunction, the court made the following observations:

1. Once a patentee claims infringement of an earlier genus patent in respect of a product, it necessarily follows that the said product was the subject matter of the earlier genus patent.
2. Only one patent can be granted in respect of one inventive concept. Therefore, a patentee cannot claim infringement of the two patents in respect of the same inventive concept.
3. The term of a patent is twenty years in terms of the Patents Act and it cannot be granted successive protection by means of separate patents.
4. The Indian law permits grant of a Markush patent. However, if one of the combinations in the Markush patent includes the product in question, it would form part of the inventive concept of the earlier patent and cannot again be claimed as an inventive concept of a subsequent patent.
5. The pleadings made on behalf of the plaintiff in the suit can be considered by the court to determine the stand of the plaintiff vis-à-vis the genus patent and the species patent.

All the above statements hold their ground individually, however, the interpretation that flowed (i.e. species prima facie being considered as disclosed in genus) seems to be in contravention of the basic principles for evaluating patentability.

On the other hand, in the matters of Novartis v. Natco (Eltrombopag Olamine-2021) as well as Novartis v. Natco (Certinib-2023), emphasizing that if an embodiment is covered in a patent, it does not automatically mean that the same was disclosed in the said Patent, the Delhi High Court has observed that the Supreme Court judgement (Novartis-Gleevec matter) does not equate coverage with disclosure. It merely holds that vast gap was not to be encouraged.

The result is a fragmented and unpredictable jurisprudence - one judicial stream collapses the doctrinal boundary between genus and species and the other maintains it. For pharmaceutical patentees and generic manufacturers alike, this inconsistency complicates validity assessments, interim-injunction strategy and freedom-to-operate analysis, underscoring the urgent need for doctrinal clarity on the disclosure-coverage divide.

Need for Balanced Claim Drafting and Judicial Consistency

In this light, innovators must approach claim drafting with balance - avoiding excessively broad genus claims unless supported by adequate data and representative working examples capable of withstanding scrutiny. At the same time, courts would benefit from applying a consistent standard in genus–species disputes, preserving the distinction between coverage and disclosure unless a clear justification exists for departing from it. There is also scope for policymakers to articulate clearer guidance on the level of disclosure required for broad chemical or pharmaceutical claims.

Until greater doctrinal clarity is achieved, the disclosure–coverage divide continues to be one of the most sensitive and consequential issues in Indian pharmaceutical patent jurisprudence.

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