Known Substance and Known Efficacy

1While mere discoveries have been excluded from patentability in United Kingdom, the practical application of a discovery may be the subject matter of a patent. (See Genentech Inc’s Patent (1987) RPC 553, p 566 (Pat ct), (1989) RPC 147, pp 208, 240 (CA).) Under the Patents Act a discovery to be patentable will be subject to the conditions imposed by s 3(d). The first part of s 3(d) and the explanation create a rebuttable presumption that the discovery of a new form of a known substance will be regarded as the same substance, unless the applicant is able to show that the new form differs significantly in properties with regard to efficacy. In this regard, the criterion of enhanced efficacy, which may be regarded as a component of utility or usefulness, will be similar to the requirement of ‘practical application of a discovery’ as recognised by the British patent law. (Genentech Inc’s Patent (1989) RPC 147, pp 208, 240 (CA).)

2A discovery, an invention or an identification of a new form of a known substance implies finding a different form of an already known substance. The law with regard to patentability of discoveries, as practised by various WTO member countries, show a varying range of positions, which is yet another indication that member countries can derogate from the exceptions mentioned in the TRIPS to expand further the exceptions to patentability. On the one hand, we have the US law which states that all discoveries are patentable. Section 101 of the US Code reads:

35 USC 101 Inventions patentable.

Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title [Emphasis supplied].

3On the other hand, we have many countries like Argentina, Austria, Brazil, Chile, China, Finland, Malaysia, the Philippines, Russia and South Africa which impose a blanket ban on discoveries. (See Argentina Patent Law, art 6; Austria Patent Law, s 2; Brazil Industrial Property Law, art 10; Chile Industrial Property Law, s 37; China Patent Law, art 25; Finland Patents Act 1967, s 1; Malaysia Patents Act 1983, s 13; Philippines Intellectual Property Code, s 22; Russia Patent Law, art 4(2); South Africa Patents Act 1978, s 25(2).) All the above countries fully exclude discoveries from patentability. The relevant provision in the South African Patents Act 1978 is reproduced below, as an illustration:

25. Patentable inventions

… (2) Anything which consists of -

(a) a discovery; … shall not be an invention for the purposes of this Act.

4Viewed in the light of the above two extreme positions on patentability of discoveries, s 3(d) may be seen as a middle-path which allows for patentability of discoveries of a new form of a known substance which result in the enhancement of the known efficacy of that substance. The criterion of enhanced efficacy is a condition imposed by the Patents Act to qualify a discovery of a new form of a known substance as patentable. In this regard, s 1a of the Finland’s Patents Act 1967 imposes a similar condition on the patentability of discoveries. The relevant provision reads:

Section 1a

The human body, at the various stages of its formation and development, and the simple discovery of one of its elements, including the sequence or partial sequence of a gene, cannot constitute patentable inventions. An element isolated from the human body or otherwise produced by means of a technical process, including the sequence or partial sequence of a gene, may, without prejudice to the provisions of paragraph 1, where the requirements for patentability are fulfilled, constitute a patentable invention, even if the structure of that element is identical to that of a natural element.

5The above provision imposes a similar condition on discovery of an element which has a structure identical to that of a natural element. For such a discovery to be patentable, Finland’s Patents Act 1967 requires the element to be isolated from the human body or to be produced by means of a technical process.

6The intention of the legislators will become more apparent when the use of the word efficacy is understood. Efficacy means the effectiveness of substance. The term efficacy is a well-understood in the pharmaceutical field. Efficacy of a drug involves a degree of potency as a drug. Bioavailability of a drug is one of the characteristics that affect the efficacy of a drug. It is also possible that ‘known efficacy’ may mean clinical efficacy in cases where the clinical efficacy of the known substance is already determined. Clinical efficacy is a regulatory requirement under the Drugs and Cosmetics Rules 1945, and as such importing the concept of clinical efficacy, which will require phase III trials to be conducted, may impose an unreasonable restriction on patentability. (See Drugs and Cosmetics Rules 1945, sch Y.)

7In the case of a pharmaceutical, the reference to a ‘property’ of a known substance means the physicochemical properties of the drug such as the solubility of the drug in aqueous and other media, the stability of the drug in solution, bioavailability, interactions between the drug and excipients (inert substances) etc. The first part of s 3(d) uses the term ’efficacy’ to describe the property of a drug. Thus, the first part deals with an increase or improvement of a ‘known property’ of a known substance, whereas the second part concerns with a ’new property’ of a known substance.

8The importance of two factors should not be misplaced in determining the scope of the first part of s 3(d). First, the fact that said clause deals with known substances. It cannot be argued that the patent is for a new substance. Whether a new form of an old and known substance could itself qualify it as a new substance for the purpose of novelty and obviousness is an issue on which there is no consensus. One only needs to look into the practice followed by various countries in the case of selection patents to understand the lack of agreement with regard to granting patents for known substances. Secondly, the first part of s 3(d) regards as an invention, any improvement (enhancement) on the known property (efficacy) of a known substance. Thus, when read in the light of the second part of s 3(d), it would emerge that the only way the first part can be read is to cover patents for improvements.

9In Merck Sharp and Dohme v Glenmark Pharmaceuticals (2015) (para 56) the Division Bench held that “Section 3(d) does not work backwards, such that two independent patent claims are to be construed in reference to each other. Each claim is regulated by its own terms, subject to the statutory prescriptions of inventive step and industrial applicability”.

10In Kudos Pharmaceuticals v Natco Pharma (2024), where it was contended “that the specifications for Olaparib do not contain any data to indicate enhanced efficacy over the prior art IN'218” (para 66), the Delhi High Court held at the interlocutory stage that “Section 3(d) ... applies only to ’new forms’ of ‘known substances’.” The Court further held that “It cannot be said that Olaparib is a new form of the Markush Claim I in IN'720.” (para 67)