The origin of the modern statutory patent system is generally traced back to the Venetian Patent Statute of March 19, 1474 which stipulated that patents may be granted for "any new and ingenious device, not previously made" provided it was useful1. Since then, it has been the fundamental principle of the law of patents that they be granted only for inventions which are new and useful. That is to say it must have novelty and utility. Such is also the position under Indian law2.

As patents generally provide a lucrative monopoly over a product or a process, it is often in the best interest of an inventor to obtain a patent though they only have a limited life. In India the term of a patent only extends to 20 years from the date of filing an application for the patent3. Thus, many inventors are incentivised to find innovative and ingenious ways to obtain a new patent on the goods or processes which were previously patented. This process is commonly referred to as the evergreening of a patent.

This article intends to cover the legality of the practice of evergreening of patents as per Indian law by primarily analysing the relevant provisions of the Patents Act, 1970 ("the Act") and by highlighting the criteria for determining evergreening.

I. Defining 'evergreening'

"Evergreening" is an informal term used to label practices that have developed in certain jurisdictions wherein a trifling change is made to an existing product, and claimed as a new invention. The coverage/protection afforded by the alleged new invention is then used to extend the patentee's exclusive rights over the product, preventing competition.An example would be when in the pharmaceutical trade brand-name companies patent "new inventions" that are really just slight modifications of old drugs, it's called "evergreening"4.

Based on the above, what would fall within the scope of 'trifling' would essentially determine whether there is an attempt at evergreening a patent or whether it is eligible to be patented, thus the door is not entirely shut on patenting an existing invention with some changes. In order to understand what constitutes a trifling change we must now direct our attention to the provisions of the Act.

II. Analysing the relevant provisions of the Act

Before, analysing the provision of the Act tackling evergreening we must first understand what can be patented. A patent can only be granted for an invention5 which is defined under Section 2(j) of the Act as a "new product or process involving an inventive step and capable of industrial application". The Act further defines an 'inventive step' under Section 2(ja) as "a feature of an invention that involves technical advance as compared to the existing knowledge or having economic significance or both and that makes the invention not obvious to a person skilled in the art". Thus, on a combined reading of the aforesaid sections, to qualify as an invention, a product must6: (i) be new; (ii) be capable of being made or used in an industry; (iii) come into being as a result of an invention which has a feature that (a) entails technical advance over existing knowledge; or (b) has an economic significance and (c) makes the invention not obvious to a person skilled in the art.

Now, even if an invention meets the above outlined threshold it may still not be patentable if it is hit by the provisions of Section 3 of the Act. Section 3 stipulates what are not inventions for the purposes of the Act. It is here that we find the anti-evergreening provision7 embodied in Section 3(d) of the Act, which is reproduced hereinbelow:

"(d) the mere discovery of a new form of a known substance which does not result in the enhancement of the known efficacy of that substance or the mere discovery of any new property or new use for a known substance or of the mere use of a known process, machine or apparatus unless such known process results in a new product or employs at least one new reactant.

Explanation.-For the purposes of this clause, salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations and other derivatives of known substance shall be considered to be the same substance, unless they differ significantly in properties with regard to efficacy;"

A perusal of Section 3(d) makes it clear that it applies where there is a 'mere discovery' of a new property/new use of a known substance of the 'mere use' of a known process, machine or apparatus. Unless, it results in the enhancement of the efficacy of the known substance or unless such known process results in a new product or employs at least one new reactant. Resultantly, Section 3(d) has to be understood as a positive provision that in fact recognizes incremental innovation while cautioning that the incremental steps may sometimes be so little that the resultant product is no different from the original8.

III. Determining 'evergreening'

Whether or not a patent for a particular invention would be hit by Section 3(d) must be determined on a case by case basis depending on the nature of the product or process. The standards applicable in this evaluation would of course also vary on the basis of the industry that the product or process pertains to.

With respect to pharmaceuticals, which have been the greatest generator of jurisprudence in this field in India, the Delhi High Court in Cipla Ltd v F. Hoffman-La Roche Ltd.9, held that Section 3(d) envisages a variety of derivatives of known substances, such as (i) a compound which is not active in itself, but is metabolized in the body to form an active drug known as prodrug. For eg., chloramphenicol succinate ester is used as an intravenous prodrug of chloramphenicol, because pure chloramphenicol does not dissolve in water; (ii) a composition (combination of two or more active ingredients or combination of a pharmaceutical carrier with a compound not used as a drug before); (iii) a drug delivery system which is a composition that its constituents enable to be administered in a particular way. As long as the product provides an enhancement to the known efficacy of the product, it would not be considered as 'evergreening' and would be patentable10. With respect to pharmaceuticals this efficacy is to be adjudged on the basis of the 'therapeutic efficacy' of the product11.

In the context of technological innovations, in a case where the suit patent was based on known elements but its novelty lied in the resultant increase in efficiency, the Delhi High Court in Communication Components Antenna Inc. v Ace Technologies Corp.12 negated an objection to the suit patent under Section 3(d) stating that the provision does not apply in cases where on the basis of existing technology, newer technology is developed and better efficiency is achieved. In this case the increase in efficiency was evaluated on the basis of the increase in the efficacy of the beams emitted by the antennae which were the subject of the suit patent13.

IV. Conclusion

The golden thread emanating from the above discussion is that evergreening a patent based on known substances or processes is impermissible in India. The only exception being if the applicant of a patent has been able to increase the efficacy of the product as provided for in Section 3(d) of the Act. This incentivises and protects real and discernible improvements, and mere inconsequential changes to known products would not pass muster. Thus, every application to patent an invention which is based on a known substance or process must be firmly based on an increase in efficacy without which it would not be patentable.


1. Kostylo, Commentary on the Venetian Statute on Industrial Brevets (1474), 2008 Edition.

2. Biswanath Prasad Radhey Sham v Hindustan Metal Industries, (1979) 2 SCC 511.

3. Section 53 of the Patents Act, 1970

4. Roger Collier, Drug patents: the evergreening problem, CMAJ. 2013 Jun 11; 185(9): E385-E386. Available at:

5. Section 2(m) of the Patents Act, 1970

6. Novartis AG v Union of India, (2013) 6 SCC 1.

7. Parliament of India Rajya Sabha, Department Related Parliamentary Standing Committee On Commerce, One Hundred and Sixty First Report - Review Of The Intellectual Property Rights Regime In India, 2021; Novartis AG v Union of India, (2013) 6 SCC 1;

8. F. Hoffman-La Roche Ltd. v Cipla Ltd, 2015 SCC OnLine Del 13619 : (2015) 225 DLT 391 (DB) : (2016) 65 PTC 1 (DB) : (2015) 4 Civ LT 500

9. 2015 SCC OnLine Del 13619 : (2015) 225 DLT 391 (DB) : (2016) 65 PTC 1 (DB) : (2015) 4 Civ LT 500

10. Novartis AG and Another v Natco Pharma Limited, 2021 SCC OnLine Del 5340 : (2022) 89 PTC 1.

11. Novartis AG v Union of India, (2013) 6 SCC 1.

12. 2019 SCC OnLine Del 9123 : (2019) 79 PTC 270.

13. See Also: Communication Components Antenna Inc. (Earlier Known As Ten XC Wireless Inc) v. Mobi Antenna Technologies (Shenzhen) Co. Ltd. and Others, 2021 SCC OnLine Del 3948 : (2021) 87 PTC 504 : (2021) 283 DLT 286.

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.