The concept of coverage and disclosure in patents was thoroughly discussed in Novartis case[1]. Patent applications for genus-species are widespread in the pharmaceutical industry. These applications are not confined to the aforementioned industry, but can also be found in other fields such as engineering.

The concept of genus-specie patents could be understood with the help of an example such as mother-child relationship. Though child comes out of mother but still child has its own identity. In the same way, we can say that albeit genus patent covers the invention broadly but specie patent discloses specific subject matter and claims it.

When the genus patent has disclosed certain process or technique on how to arrive at specie patent and the person of ordinary skill (POSA) is able to make it then the patent is said to be covering and disclosing the specie patent and there is no need to file the separate patent application for the specie subject matter[2].

However, when the person of ordinary skill is not able to arrive at the specie patent through genus patent, which is covering 'n' number of compounds, then it can be said that genus patent has covered specie patent but has not specifically disclosed the subject matter.

Analysis of Coverage-Disclosure dichotomy

In pharmaceutical industry, the concept of Markush claims is well known. These types of claims are used for covering large number of compounds. However, it is well-known that it is not possible to disclose all the compounds. When certain chemical combinations are specifically mentioned in order to arrive at different compounds and the person of ordinary skill is able to arrive at these compounds merely by reading the detailed description of the genus patent then the genus patent is covering as well as disclosing the specific compounds and if these compounds are claimed in separate patent application then they are obvious and subject to revocation under Section 64(1)(f) of Patent Act 1970.

Further, when the genus patent is covering millions of compounds through different chemical combinations but not disclosing the technique to achieve all these compounds and the specie patent application is filed claiming the specific compound out of the genus patent and has described the method for achieving it then it can be termed as non-obvious with respect to the genus patent.

Boundary of any claim of a genus patent has to be evaluated in view of the disclosure made in the complete specification of that genus patent. The claim must be understood based on the claim's phrasing in context of the enabling disclosure of the detailed description.

But there is another aspect of looking into genus-specie patents. In case, the genus patent has been drafted in such a way that although it is covering the specie patent but the enabling disclosure is not clearly indicated and separate patent application is filed claiming the specific invention then such invention should be tested in the light of section 2(1)(j) and section 2(1)(ja) of the patent act 1970.

If the subject matter of the specie patent is not novel or lacks inventive step then it should not be granted patent. One of the major thing that has to be checked by the controller is that, in case, the genus patent is covering large number of compounds and claiming a markush formula then the enabling disclosure should have been provided for all these different compounds. If this is not the case then the patent should not be granted by virtue of section 10(4) and section 10(5) of the patent act 1970.

Novartis AG vs Union of India case (supra) is the landmark case in this regard. The Supreme Court of India has elaborately discussed the concept of coverage and disclosure with reference to genus-specie patent. The issue that was to be adjudicated by the court was whether β-crystalline form of imatinib mesylate is invention under section 2(1)(j) and section 2(1)(ja) of the patent act or not and if so then what is the role of section 3(d) of the patent act 1970.

The petitioner argued that β-crystalline form is the new invention and the imatinib free base is the relevant prior art of this invention. They further argued that α & β forms of the imatinib mesylate have increased bioavailability which results in increased efficacy and it has properties that can prevent tumour. So they submitted that section 3(d) should not be applicable.

They further argued that imatinib free base was the prior art and with respect to it, the present β form has technical advancement and is novel and hence satisfies the patentability criteria under section 2(1)(j) and section 2(1)(ja) of the act. The petitioner also argued that the opponents have also filed for the different crystalline forms of the imatinib mesylate and have successfully received the patent.

The respondent argued that the properties of β-crystalline form have same properties as the other salt forms of the free base usually have. Therefore they submitted that this β-crystalline form is neither novel nor inventive. They further argued that the article published on cancer research earlier than the patent application filed claiming β-crystalline form is the proof that imatinib mesylate was known for treatment of tumour prior to the filing of the impugned patent application. They further argued that economic significance does not refer to the profit earned by inventors but the significant cost reduction to the consumers.

The Supreme Court rejected the arguments advanced by the petitioner and held that β-crystalline form of imatinib mesylate is the new form of the known substance as per as section 3(d) of the patent act. They further held that the term efficacy mentioned in the section 3(d) refers to the therapeutic efficacy. Increased bioavailability does not mean increase in therapeutic efficacy. The court held that there cannot be a huge gap between coverage and disclosure.

This gives an impression that there is a gap between coverage and disclosure but it should not be huge. Hence, one cannot say that both coverage and disclosure are same and whatever is disclosed will only be held as covered. The court concluded that through skillful drafting, it is possible to claim only the markush claim and later patentee may claim that the specie patent was not disclosed in the genus patent.

But the subject matter claimed in the specie patent should be analyzed keeping in mind about the interpretation of the term ''efficacy'' in section 3(d) of the patent act. If the subject matter of specie patent has therapeutic efficacy and further it passes the test of section 2(1)(j) and section 2(1)(ja) and the enabling disclosure is not provided in the genus patent then only the specie patent is eligible for the grant.

The Supreme Court decision in Novartis case was the landmark judgement. This judgement was later cited in various cases by High Court. In FMC Corporation vs Best Crop[3], the Delhi High Court held that the Supreme Court used the word dichotomy between coverage and disclosure in Novartis case rather than distinction. Since the word dichotomy was used and not distinction, so there should not be huge gap between coverage and disclosure. The Court further said that they should be separated by fine line and both are not same.

In Merck vs Glennmark[4], the Delhi High Court held that claim construction involves careful reading of the claims along with the enabling disclosure to find whether the person skilled in the art is able to arrive at the invention. Hence the court concluded that without proper disclosure of invention, a claim cannot sustain as per the Indian Patent Act.

In Eisai vs Reddy[5], the Delhi High Court reiterated the findings of the Supreme Court and said that the invention should have the enabling disclosure so that the person skilled in art is able to make the invention.

In recent judgement of Novartis vs Natco[6], the Delhi High Court gave an observation stating that there is some distinction between the vast coverage of the claim on the basis of its wordings and claim coverage which the person is entitled to get the under section 48 of the patent act. The court further said that coverage of the claim would be interpreted through claim construction and claims should be read with enabling disclosure.

After analyzing all these aforementioned judgements, it is clear that in any invention consisting of Markush claim, the claim should be fairly based on the enabling disclosure otherwise the Markush claim of the genus patent might have covered the subject matter of specie patent application but since the disclosure is made only in the specie patent, so the specie patent application would be applicable for the grant subject to fulfillment of other criteria.

Conclusion
The dichotomy of coverage and disclosure is vastly covered through various judgements of the High Courts and the Supreme Court in view of the genus and specie patents. There are few points that are to be kept in mind while understanding the coverage-disclosure conundrum:

• The genus might cover millions of chemical compounds through markush claims but only those compounds that the person of ordinary skill could make after reading the disclosure in the specification would be said to be disclosed.
• Further, section 3(d) of the patent act would come into play as the specie patent application would be tested for therapeutic efficacy.
• Furthermore, the subject matter of specie patent needs to be tested under section 2(1)(j) and section 2(1)(ja) of the patent act.
• If the controller is satisfied with the abovementioned criteria then the specie patent would be granted.

End-Notes:

1. AIR 2013 SC 1311
2. Novartis Ag vs UOI
3. MANU/DE/1220/2021
4. MANU/DE/2963/2015
5. MANU/DE/1621/2019
6. MANU/DE/3511/2021