16 August 2022

Divisional Applications And Plurality Of Invention In India

The principle of "unity of invention" is near universal to patent law and entails that a single patent application must relate to a single invention or to a group of linked inventions having...
India Intellectual Property
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The principle of "unity of invention" is near universal to patent law and entails that a single patent application must relate to a single invention or to a group of linked inventions having a 'single inventive concept'. If the application lacks unity of invention, the applicant may split the original application, and file a "divisional application" seeking protection for the (additional) plurality of inventions.

The Delhi High Court, Boehringer Ingelheim International GMBH v. The Controller of Patents (C.A. [(COMM.IPD-PAT) 295/2022 & I.As.10369-70/2022], spelt out the concepts of "plurality of invention" and "divisional applications", explaining how plurality could be established and when such applications could be permitted. It held, in summary, that a divisional application could not be filed since there was no "plurality of inventions" in the parent application.


The original (parent) patent application contained 18 claims, including two numbered 15 (hereinafter claims "15" and "15A"). In response to the First Examination Report, the applicant deleted all the claims except claims 14, 15 and 15A. These remaining claims were directed to an isolation or storage medium, and a method of enhancing the vitality and secretion capacity of islet of Langerhans. Subsequently, the applicant also filed voluntary amendments to the application, adding certain product claims relating to the medicament combination of DPP IV inhibitor with Metformin and Telmisartan. However, these voluntary amendments were not taken on record as they were found to be beyond the scope of the original claims of the parent application, and therefore, in contravention of section 59 of the Patents Act, 1970 (the Act). The parent application and the amendments were eventually refused by the Indian Patent Office (IPO).

Even before the order of refusal was issued, the applicant filed a divisional application spun off from the parent application. The divisional application consisted of the product claims based on voluntary amendments filed in the parent application, and some new claims.

The IPO refused the divisional application as well, stating that the claims in the divisional application were already examined and refused in the parent application, and therefore the same claims could not be allowed in another application. The Controller also stated that "failure to get patent on the parent application is not eligible criteria for divisional application. Very important to note that in case, if the amended claims are allowable in the present application then the same claims could have been allowed in the parent application itself if meeting all criteria."

The matter reached the Delhi High Court, which closely examined the concept of plurality of invention, and whether divisional applications could be filed for claims that were not part of the claims in the parent application.

Unity and plurality of invention

The court undertook an extensive analysis of the law as contained in Sections 10 and 16 of the Act.

The court said that Section 16 made it clear that a divisional application had to be an application that arose from parent application disclosing a "plurality of inventions", as specified by Section 16(1), which states that "the claims of the complete specification relate to more than one invention". Section 16(3) also clarifies that there cannot be any duplication of claims in the parent and divisional applications.

On the question of how to determine "plurality of inventions", the court deferred to Section 10 of the Act, which elaborates on the meaning of complete specification and scope of claims. It elucidated further thus:

"The content of the specification describes the invention. The complete specification also describes the procedures, processes, methods, including the best methods. But what is crucial to note, is the fact that the invention itself is defined in the claims. While such claims do have to be based on the disclosure in the specification, however even if a person does not read the complete specification and wishes to identify the invention, the place to look for it is in the 'Claims'. The Invention thus resides in the Claims. Accordingly, "unity of the invention", "plurality of inventions" and whether they form a "single inventive concept" has to be gleaned from a reading of the claims.

The court held that using this understanding of how an invention is ascertained in a patent application, under Section 16 of the Act, "plurality of inventions" should clearly exist in the claims of the original parent application and within the scope of the parent specification.

The court observed that if the applicants were permitted to file divisional applications on the basis of disclosure in the complete specification, without such inventions being claimed in parent applications, the fundamental rule of patent law 'what is not claim is disclaimed' would be defeated.

The court also reiterated that Section 59 makes it clear that amendments beyond the scope of the specification and claims would not be permissible.


The court finally held that under Section 16, "plurality of inventions" must exist in the claims of the parent application. The claims of the divisional application were not included in the parent application but were based on the disclosure of the parent application. Once the claims were not sought in the original application and the subject matter of these claims was clearly disclosed in the content of the complete specification, the subject matter is to be treated as having been disclaimed. In other words, the court said that the parent application cannot be interpreted to have included a "plurality of inventions", i.e., completely new claims, that could be patentable by way of a divisional application.

In a rare recognition of judicial delay caused by the institution of a suit without merits, the court took particular note of the inordinately long duration that the present matter had taken to conclude: the parent application was originally filed in 2008, followed by three Amendments and a divisional application, before reaching the Delhi High Court. The court decided a penalty was in order and dismissed the appeal with directions to the applicant to pay certain costs.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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