A patent is a proprietary right granted for protecting new inventions, which have an inventive step and can be applied for industrial utilization. The process of granting and obtaining a patent is usually time-taking, and more than often, it is argued that much life of the patent is consumed due to such administrative measures, as a result of which the actual life cycle of a patent becomes much shorter. During the period of securing a patent, it may so happen that the inventor obtains a better result from altering some specific aspects of the invention. These improvements or minor modifications can be adjusted within the existent Patent Application, which may be beneficial to the inventor in saving time and avoiding the lengthy route of re-filing. This provision can be found in many national legal frameworks dealing with patents like those in the United States of America, Australia, New Zealand, South Africa, and Greece.

Patent of Addition or the Continuation-in-Part Application

Simply put, a patent of addition is a prototype of a patent. It is generally referred to as a weapon that protects the product or process in addition to its improvements or variations. These improvements or modifications are generally left out in the parent application, but as a result of continuous experiment and research or market feedback, they are brought up to the attention of the examiner to be extended and given the like protection. In India, Australia, and New Zealand, this is known as the Patent of Addition; however, in the USA, it is referred to as the Continuation-in-Part. They both share a few similarities, but there are some clear differences between the two as well.

Patent Cooperation Treaty (PCT): The PCT, in its Article 2, defines the meaning of ‘application.’ An application means an application for the protection of an invention; reference to an ‘application’ shall be construed as references to applications for patents of inventions, inventors’ certificates, utility certificates, utility models, patents or certificates of addition, inventors’ certificates of addition and utility certificates of addition. Therefore, there is no dispute in embracing the provision as the requirement to facilitate the same was envisioned and stated in the Treaty. Therefore, as a result of such inclusion within the Treaty, in principle, if an applicant wants an international application to be treated as a patent of addition or continuation-in-part in the designated state, the said inventor may indicate the intention in the request for national phase entry.

The Indian Practice: The suggestion to include within the Patent Act such a flexible provision as that of the patent of addition was introduced by the Lord Swan Committee, which stated that:

“The purpose of patent of addition was to provide reliefs to the applicant who has failed to draft their claims in a way to adequately cover their invention, by giving them an opportunity to rectify the claims they have made, in cases where the circumstances permit this.”

Furthermore, the Justice Ayyanger Committee also stated that the subject matter of the patent of addition should be a disclosure stating an addition or modification and not a complete new claimed invention itself.

As a result of the said developments, India embraced the provisions within its Patent Act, 1970. Section2 (1)(q) defines ‘Patent of Addition’ as a patent granted under Section 54, which enumerates the vital characteristic features that qualify a modification or addition as a ‘Patent of Addition.’ These features are as follows:

  • A patent of addition can be filed only on or later than the date of filing the parent patent application (Section 54).
  • The term of the patent of addition coincides with that of the parent patent application and cannot exceed the same. Therefore, the lifecycle is a term equal to the patent (Section 55).
  • If the parent patent application is revoked, a request may be made to the Controller of Patents to the effect that the patent of addition shall be made an independent patent for the remaining term of the parent patent application (Section 55).
  • Furthermore, any improvement or modification in the main invention described in the complete specification of the patent of addition shall not be questioned on the grounds that the invention ought to have been the subject of an independent patent (Section 56).

 The South African Practice: In the South African Patents Act, 1978, a reference to the patent of addition is found in Section 39, which states that any inventor who seeks to add, improve, or modify the existent invention can file for the addition to that. However, the limitation is placed that no such addition shall be made to broaden the scope of the claims of the parent patent application.

The Practice in the USA: ‘Continuation-in-Part’ is considered as a modification or an improvement of an existing patent application. It is generally referred to as an ‘add-on’ to the parent patent application. Just like in the case of patent of addition, the continuation-in-part application is also beneficial to the applicant since it permits a certain degree of flexibilities to be adjusted in the application. It also helps to claim the subject matter in the original application, including the benefit of claiming the date of filing of the original patent application. The downside of seeking a continuation-in-part application is that the period when the patent matures is cut short since the application’s lifecycle is counted from a backdate of the earlier application.

The Practice in the European Union: In the EU, the European Patent Convention does not provide a provision for patent of addition. However, certain Member States within Europe have made such allowance for embracing the said position. Countries like Austria, Turkey, and Greece can be counted as a few exceptions to the vast majority of nations that do not provide for ‘Patent of Addition.’


Difference between Continuation-in-Part and Patent of Addition

Continuation-in-Part Patent of Addition
It can be filed any time before the grant of the parent patent. It can be filed any time before the lapse of the patent term.


The renewal fee of the patent has to be separately paid. There is no separate renewal fee paid for the patent of addition unless the parent patent application is revoked.



The continuation-in-part application may have different priority dates than the parent application.


The date of filing a patent of addition can be either the same or be later than the parent application but cannot be before the parent application.

Is it Always the Right Choice to File for Patent of Addition?

Filing a patent of addition may usually seem to be convenient since it helps to keep the patent family alive while making incremental additions and improvements upon the parent application. Also, most of the additions may not even qualify to be independently filed in the form of patents, and therefore, filing a separate application may not always be justified. It saves the cost knowing the lofty investment that accompanies it. The renewal fee, especially in the case of patent of addition (however, no continuation-in-part), may also be an additional reason for resorting to such a choice as none needs to be paid. An application for patent of addition can serve as a tool for future divisional applications and even more patent of addition applications.

Despite the mentioned positives, it may not always be the right choice irrespective of circumstances. The reason lies behind the life term of these rights. A standard term for a patent is merely 20 years after filing the patent application and submitting the disclosed attributes of the invention. The term of a patent of addition is limited to its parent patent application’s term, which may be detrimental to the inventor’s interests in cases where the remaining lifecycle may not be substantial enough to accrue benefits to the inventor. Consider, for example, where a patent of addition is filed in 2020, but due to the priority date of the parent application in 2005, the remaining period accounts for only five more years until 2025, which may not be substantial enough to realize its true potential. Had a standalone application been made, it would have secured better and significant make-up in terms of revenue. Also, if the parent patent relating to the claimed invention is revoked based on obviousness or lack of inventive step due to uncovering a particular prior art, the patent of addition might be under attack, and thereby, be revoked based on that prior art.

In some instances, a patent of addition may itself serve as a cause for raising objections within the parent patent application. It may be asserted that the new matter, as introduced in the patent of addition, is necessary to make and use the invention and is thus critical for enablement in the parent application. Therefore, it may lead to the challenging of the parent application, which may lead to its invalidity. Lastly, as has been discussed above, that in some countries, there is no provision of patents of addition; if a patent of addition is filed in such jurisdictions where the patent of addition provisions are not available, then objections concerning the obviousness or lack of inventive step over the parent application may arise.

Concluding Remarks

Deciding upon whether to file a patent of addition or a fresh patent application altogether is a crucial choice to make, especially when filing for a patent of addition appears to be an appealing option. In instances where support for the new subject matter of the patent of addition is not set out with certainty in the parent patent application, it may be advantageous to file a distinct, unrelated application to utilize the distinctiveness of the new claims and obtain the benefit of a full patent term. Therefore, such determination should be made after subjectively weighing the pros and cons.