The subject matter of Indian patent IN 229051 (IN’051), granted to Novartis AG on 02.13.2009, relates to a pharmaceutical composition comprising a combination of Valsartan or a pharmaceutically acceptable salt thereof and Sacubitril or a a pharmaceutically acceptable salt thereof and an acceptable carrier. The patent application was filed on 07/09/2004 as an entry into the national phase of the Patent Cooperation Treaty (PCT) application of 01/16/2003, claiming priority of the United States’ application from 01.17.2002.

Novartis filed a lawsuit in Delhi High Court for infringement of IN’051 and sought to prevent Natco Pharma Ltd and its agents from manufacturing, importing, selling, offering for sale, the drug VALSAC, allegedly a combination drug of Valsartan and Sacubitril sold by Natco Pharma Limited. The defendant countered that their product is a supramolecular structure, allegedly a single compound being different from the claimed combination and, therefore, outside the scope of the lawsuit’s patent. He further argued that the plaintiff made a misleading and false statement that the supramolecular complex is covered by the IN’051 prosecution patent. The defendant also filed a counterclaim for revocation of patent IN’051 claiming that the subject matter was not patentable under Sections 3 (d) and 3 (e) of the Indian Patent Act 1970.

Novartis has stated that it has continued its research and arrived at the supramolecular structure of Valsartan and Sacubitril, and has submitted application No. 4412 / DELNP / 2007 (4412) dated 08.11.2006 for the same. The defendant filed an opposition prior to the issuance of application no. 4412, on the grounds that the supramolecular structure is disclosed in the prior art, i.e. the lawsuit patent. Natco also insisted that the prosecution’s patent does not cover the supramolecular complex, a fact acknowledged by the applicant before the authorities concerned at the time of the pre-grant opposition to the 4412 application. The supramolecular complex in question , as argued by the respondent, is posterior to the patent and, therefore, cannot be covered by the patent for prosecution. The defendant asserted that he does not contradict the claims of the prosecution patent because the supramolecular complex is not covered by the claim. The applicant asserted that the prosecution patent did not disclose any method of synthesizing supramolecular complexes as disclosed in application no. 4412.

The defendant’s claim was dismissed and an injunction order was issued in favor of Novartis on 28e October 2021. The defendants were prohibited from manufacturing, selling, importing, offering for sale any pharmaceutical composition comprising a combination of Valsartan or a pharmaceutically acceptable salt, and Sacubitril or a pharmaceutically acceptable salt and a pharmaceutically acceptable carrier or more precisely a pharmaceutical composition comprising a combination of Sacubitril + Valsartan in the form of a sodium salt complex or in any other form which may constitute an infringement of the Indian patent IN’051 of the applicant.

Case analysis

The defendant referred to application no. 4412 and argued that it covers the supramolecular complex while IN’051 does not cover it.

Apart from a number of deliberate issues in the case, one of the issues concerned the importance of claim no. 4412 in relation to the present infringement case. The claims of application no. 4412 influence the assessment of the infringement of IN’051? In other words, should the infringement case depend on the patentability of application no. 4412? In the event that the patent for application no. 4412 is tuned, does this mean that IN’051 does not cover the supramolecular complex. In the event that the application patent is refused under section 3 (d), would this amount to concluding that the supramolecular complex is another form of the composition claimed in IN’051 and, therefore, covered by this one.

Section 3 (d) of India’s Patents Act 1970 raises the bar for patentability and states that the mere discovery of a new form of a known substance which does not lead to improved efficacy known substance or the mere discovery of a new property or new use of a known substance or the mere use of a known process, machine or apparatus, unless this known process does not results in a new product or uses at least one new reagent. Salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations and other derivatives of a known substance should be considered the same substance, unless they differ significantly in their properties with regard to efficacy. In other words, if a product is patented, its salt, its polymorph, etc. cannot subsequently be re-patented, unless its effectiveness is significantly improved over the earlier patent.

An answer to the questions raised above was provided in Merck v. Glenmark[1], in which the Bench Division found that the construction of the claim to determine the coverage of the prosecution patent must be determined objectively on its own terms with respect to the words used by the inventor and the context of the invention in terms of existing knowledge in the industry. A patent is interpreted by the terms used by the inventor and not by the inventor’s subjective intention as to what was supposed to be covered.

These issues were also addressed in Merck Sharp and Dohme Corporation (MSD) and Anr v. Glenmark Pharmaceuticals[2]. A subsequent application (5948 / DELNP / 2005) to the prosecution patent in this case was abandoned and the fallout from the abandonment of the prosecution patent was deliberate. The court said later abandonment cannot remove what was patented earlier or include something that was excluded earlier. The application was abandoned due to section 3 (d) because MSD argued that sitagliptin dihydrogen monophosphate had no improved therapeutic value and would not obtain an independent patent but would would also be included in the original patent. Glenmark argued that this would be contrary to the purpose of section 3 (d) – although improvements to patents not disclosed in the patent application are affected by this section, it does not mean that they are included in the original patent. These arguments make the interpretation of the claims dependent on the scope of Article 3 (d) with respect to the improvements made to the basic patents.

Section 3 (d) does not work backwards, so two independent patent claims must be interpreted with reference to each other. Each claim is settled on its own terms, subject to the legal requirements of inventive step and industrial applicability. The mere fact that an inventor applies for a subsequent patent which is already objectively included in an earlier patent, but which the inventor subjectively believes needs a separate patent application, does not mean that it should be taken. at face value and therefore neither Article 3 (d) nor the abandonment of the subsequent patent application can be used to interpret the terms of a prior patent, which must be interpreted on its own terms. The inventor’s intention, through the use of the words which have been employed, must be judged, but the subjective intention cannot replace a detailed analysis of the text of the patent.

In other words, neither the claims of application no. 4412 nor its fate can affect the infringement case, as one has to rely on the construction of the IN’051 claim. The Court relied on the plain and plain language of the claims of IN’051 that the composition comprises a combination of Valsartan or a pharmaceutically acceptable salt thereof and Sacubitril or a pharmaceutically acceptable salt thereof. here and a pharmaceutically acceptable carrier and the defendant’s product fell within the scope of the claims.