21 May 2013

Patent of addition

by Anupama Ravindran Sribindu Chivukula


After arriving at an invention, it is often the case that there is an improvement or modification of the invention. The improvements or modifications may happen as a natural process of improving an invention, or as a result of feedback received from the market or the industry. In such cases, where the invention is already protected by a patent, the improvement or modification over the original patented product or process may be protected by a “patent of addition” in India.  



Patents Act, 1970 (Act) is largely based on the recommendations of the Justice N. Rajagopala Ayyanger Committee (Ayyangar Committee). In its report titled "Report on the revisions in the patent law", the Ayyangar Committee suggested addition of a clause to enable applications for patents of addition, in line with Section 26 of the UK Patent Act, 1949. In the UK, the Lord Swan Committee (1948), while making recommendations for the UK Patent Act 1949, stated that the purpose of patent of addition was to provide sufficient measure of relief to applicant who have 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. Under this recommendation, the applicant may have been allowed to rectify his/her claims by filing a patent of addition, to cover the variations of the main application and could potentially allow applicants to amplify the scope of invention in the patent of addition.  The recommendations in the Ayyangar Committee Report reproduce Section 26 of the UK Patent Act.  


Salient features of patent of addition

Sections 54, 55 and 56 of the Act are specific provisions that govern patents of addition. A patent of addition is an application made for a patent in respect of improvement or modification of the invention described or disclosed in the main application for which the patentee has already applied for or has obtained a patent. The applicant has to be same for the main invention and the improvement / modification and the language of the provision suggests that if the improvement / modification involves an additional applicant, a patent of addition may not be pursued.  A patent of addition should either be on the same date or a date later than the date of filing of the main application. Therefore, in principle, a patent of addition can be filed even after the grant of the main application.          

In addition, where the improvement or modification over the main application is a subject of an independent patent, and if the patentee is the same in respect of both the inventions, the Controller may, on request by the patentee, revoke the independent patent and grant the same as a patent of addition.        

There are no special rules governing the priority date of patents of addition and hence, the default rule will apply - the date of filing of the patent of addition will be considered as the priority date, subject to other provisions in the Act.        

In case of patent of addition, Rule 13(3) of the Patents Rules states that each such patent of addition shall include a reference to the main patent or the application for the main patent  and also include a definitive statement that the invention is an improvement or modification of the invention claimed in the complete specification of the main application.


Novelty and inventive step for a patent of addition

According to Section 56 of the Act, a patent of addition cannot be invalidated, or revoked on the ground only that the invention claimed in the complete specification of the patent of addition does not involve an inventive step in view of the main application.  This was clearly well established in the case of Ravi Kamal Bali v. Kala Tech and Others [Bombay High Court, Order dated 12th Feb 2008] where the Bombay High Court dismissed the defendant's argument that patent of addition can only be granted if it has an inventive step over the main application. Nonetheless, Section 56(2) clarifies that the disclosure in the main application / patent shall be considered in determining the novelty of the patent of addition.         

This serves as a useful ex ante test for an applicant – if there appears to be a serious risk that a later modification / improvement will lack inventive step when compared to the basic invention, the applicant may choose to file such modification / improvement as a patent of addition. 


Term of patent and renewal fee

Section 55 of the Act states that the term of a patent of addition shall be equal to that of the main application and shall remain in force as long the main application is in force and expire along with that of the main application. This limitation in the term is balanced by the fact that no separate renewal fee has to be paid for a patent of addition. In the situation that the main application is revoked, the patent of addition may, upon request by the patentee, become an independent patent for the remainder of the term and shall continue to remain in force as an independent patent.  


Is it possible to file a PCT application for a patent of addition?

Section 54 of the Act only refers to an application being made for a modification / improvement and does not limit itself to any specific kind of application. Under Section 7(1A) of the Act, an international application filed under the Patent Co-operation Treaty (PCT) shall be deemed to be an application filed in India, if a corresponding application has been filed in India. Under Section 138(4) of the Act, an international application filed under the PCT designating India “shall have the effect of filing an application for a patent under Section 7, 54…, as the case may be,…”. Form-1, which is the common form to be filed for seeking a patent in India, has a separate section referring to patents of addition. Clearly, under Indian law, a patent of addition can be filed in the form of a domestic application or an international application.          

This conclusion is supported by a reading of the PCT as well. Article 2 of the PCT defines the meaning of application as follows: "application” means an application for the protection of an invention; references to an “application” shall be construed as references to applications for patents for inventions, inventors’ certificates, utility certificates, utility models, patents or certificates of addition, inventors’ certificates of addition, and utility certificates of addition.          

This definition covers patents of addition as well.  If an applicant wishes that the international application be treated as a patent of addition, or a continuation in part or other forms of protection in the designated state, he may indicate in the request for national phase entry for that application as required. However, it needs to be carefully considered whether the special privilege granted to patents of addition in India is followed in other countries where the PCT is being prosecuted. 


Patent of addition in other countries

While several countries have abolished the concept of granting patents for improvements or modifications over the main invention, some countries including India, Australia and the U.S. still continue with the practice. The U.S Continuation in Part (CIP) application is similar to the Indian patent of addition concept, since improvements or modifications over an existing patent application may be made while the patent application is still pending for grant. In a CIP application, claims may have varying priority dates based on the priority date of the first application in which the subject matter was disclosed. Nonetheless, the patent shall expire twenty years from the filing date of earliest application from which benefit is claimed, similar to a patent of addition.   



Patent of addition can be useful for protecting products or processes, and their improvements and variations in India. These will serve a useful purpose in covering improvements / modifications that were left out in the main patent. In addition, where significant objections are raised that the modification / improvements lack inventive step in view of the main invention, patent of addition provide a useful avenue through which such improvements / modifications may still be protected. The patentee need not even pay renewal fee for such patents of addition. These advantages are balanced by the fact that the term of a patent of addition cannot exceed that of the main patent. Once again, this approach seems another mechanism under the Act to prevent “evergreening” of closely related inventions.

[The authors are respectively Senior Manager and Patent Analyst, IPR Division, Lakshmikumaran & Sridharan, Bangalore]


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