Liberalising divisional patent applications in India: IPAB’s expansive approach to ‘lack of unity’ objections and second divisionals

A divisional patent application (also known simply as a “divisional”) is a patent application that is based on, or derived from, a previously-filed parent application. Divisionals are filed when the claims in a parent application pertain to more than one invention. These applications are covered under Section 16(1) of the Indian Patents Act, 1970 (the Act). This provision allows divisionals to be filed in cases where either the applicant wishes to split the application of their own accord, or if objections have been raised by the Controller on this account.

The law lays down the conditions under which divisionals can be filed, and provides some procedural guidance, but in practice, there is remains ambiguity on some aspects of these applications. For instance, after a parent application is objected to for “lack of unity”, can a Controller refuse to entertain a divisional of that parent on grounds that the earlier objections were made in error? Or, separately, are “grandchild” applications (i.e., a divisional of a divisional, or “second divisionals”) permissible? Previously rigid stances taken by the Indian Patent Office have been reversed by a liberal position taken by the Intellectual Property Appellate Board (IPAB). Tackling these issues in separate cases, the IPAB has offered clarity to applicants and expanded the scope of filing divisionals considerably.

Controller’s ‘lack of unity’ objections

Under Indian patent law, one patent application must pertain to one invention only; in other words, there must be unity of invention. In this context, objections from the Controller that prompt the filing of a divisional are usually that there is a “lack of unity” in the parent application. The law contained in Section 16 is clear that an objection of “lack of unity” is not a necessary requirement for filing a divisional application, because such applications can also be filed voluntarily by the applicant. This was also clarified by the IPAB in Milliken & Company v. Union of India.1

Once a “lack of unity” objection is made, can the Controller reverse its position on the objection and refuse to entertain the divisional? This question came up in Syntonix Pharmaceuticals, Inc v. Controller General of Patents & Designs.2 Here, the IPAB held that if a divisional application was filed in response to an objection of “lack of unity” in the parent application, the Controller cannot refuse the divisional by claiming that its earlier opinion was erroneous. The IPAB also held that when the validity of a divisional application is questioned, the applicant should be given an opportunity to amend their claims in that application. 

Second Divisional Applications 

Another issue that is occasionally encountered is that of “grandchild” applications, i.e., second divisional applications that arise out of first divisional applications. This was tackled in National Institute of Immunology v. Assistant Controller of Patents & Designs,3which validated such ‘grandchild’ applications. In this case, a first divisional application had already been granted. However, before the date of its grant, the applicant filed for a second divisional application. This was done owing to an objection raised by the Assistant Controller that the claims in the first divisional defined a multiplicity of distinct inventions. But the Assistant Controller subsequently rejected the second divisional application.

Hearing the case on appeal, the IPAB held that such second divisional applications are permissible if they are filed before the grant of their immediate predecessor, i.e., the first divisional application.

In Milliken & Company v. Union of India,4 the IPAB had allowed a second divisional application which had been voluntarily made. In this case, the Controller refused the amendment of the claims in the first divisional application. Consequently, the applicant filed for a division of their first divisional application to protect their claims. Two things worked in the applicant’s favour here: first, the patent office had taken contradictory stands at the prosecution stage of the patent applications; and second, the IPAB concluded that the applicant did not have any other remedy available. 

‘First Mentioned Application’ 

Section 16(1) of the Act illustrates that an applicant can file for a further application if their claims relate to more than one invention, before the grant of the patent that has already been filed for, which is referred to as the ‘first mentioned application.’

In the cases discussed in this note, the IPAB has clarified that the “first mentioned application” can be construed as the most immediate application, which is not necessarily always the “parent” application.

Thus, if an applicant files a second divisional application, the term “before the grant of the patent” in Section 16(1) of the Act can also be interpreted as, before the grant of the first divisional patent, since this would be the most immediate application. 


Through these decisions, the IPAB has clearly signalled that it is inclined to interpret the law on divisional applications more liberally. While this does not give license to applicants to apply for divisionals without discretion, it does appear that the IPAB is open to the allow applications for multiple inventions arising out of the same family. This is undoubtedly a progressive step in the field of divisional patent applications in India, which will impact a host of areas, including the quality of patent applications themselves, patent drafting as well as prosecution.

1 OA/61/2012/PT/MUM, dated 5 January, 2016.

OA/26/2013/PT/KOL, dated 27 June, 2014.

3 OA/21/2011/PT/DEL, dated 25 March, 2015.

4 OA/61/2012/PT/MUM, dated 5 January, 2016.