The Patents (Amendment) Act, 2005 revolutionized the patent regime in India. This amendment act incorporated the provision of granting product patents in India in the area of pharmaceutical and other chemical inventions. The three prerequisite conditions for an invention to be eligible for the grant of patent are novelty, nonobviousness and industrial applicability. With the commencement of the amendment act, patent protection in the fields of food, medicine and drug products is now readily possible. The Indian patent practice relating to the patenting of food, medicine and drug products or biological material is relatively new and thus not so well established. One major issue which has evolved due to the enactment of this new regime is whether the discovery of a new use of a known substance or pharmaceutical composition would be entitled to a patent protection or not.

This article deals with the issue of patentability of a new or subsequent medical use of a compound or composition wherein the first medical use of same is already known.

Swiss-type claim format

The origin of ‘swiss-type claim format’ is supported by the fact that the ‘discovery of new use of a known drug’ by a pharmaceutical company employs time, money and labor which makes the ‘new use’ equally worthy of patent protection as compared to the original research which established the first pharmaceutical use of that drug. To tackle the issue of establishing the ‘Novelty of Purpose,’ the European Patent Office and the Swiss Patent Office adopted the swiss-type claim format. The use of this form of claim format is derogation from the obligation for absolute novelty. Its format is  “Use of substance X in the preparation of a medicament for the treatment of disease Y.”

The Scope of Patentability of New Use of a Known Substance or Composition in various countries

There are different opinions regarding patentability of second and subsequent medical uses of known substances or pharmaceutical compositions. Under the Patent Laws of various countries, discovery of a new advantage of a known substance or pharmaceutical composition is considered as a new invention that qualifies to be patentable.

As per United States Patents Law, Code 101 “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 therefore, subject to the conditions and requirements of this title.”1 The claims addressed at the method of treatment are accepted in US, therefore it alleviates the need of swiss-type claim format. However US Patent and Trademark Office (USPTO) accepts Swiss-type claims.

According to Section 4A(3) of the United Kingdom (UK) Patents Act 1977 (as amended), “in the case of an invention consisting of a substance or composition for use in any such method, the fact that the substance or composition forms part of the state of the art shall not prevent the invention from being taken to be new if the use of the substance or composition in any such method does not form part of the state of the art.”2 That is to say, the UK Patents Act regarded discovery of a new purpose of a known drug to be novel. The second and subsequent use of a known drug was not considered as lacking in novelty if the subsequent use did not form a part of the state-of-the-art. In Wyeth's Application [1985] RPC 545, one of the claims was drafted in the swiss-type format for patenting a new therapeutic use of a known drug which was refused by the examiner and later permitted by the UK Patents court on an appeal.

In a post G2/08 practice note issued by the UK Intellectual Property Office (IPO) the swiss-type claim format was prohibited from use in any UK patent application without any equivalent “grace period”. Moreover, from the issuance of G2/08 the swiss-type claim format claiming second or subsequent medical use of a known drug was objected to by the UK IPO on the ground of lack of clarity.

India’s viewpoint

With the commencement of Indian Patents (Amendment) Act, 2005, it is now possible to obtain patent protection on a substance intended to be used or capable of being used as a medicine or drug. According to section 3 (d) of the Act, “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”3.

Consequently, to obtain a patent for the second and subsequent use of a medicament the therapeutic efficacy must be enhanced or at least a new reactant must be employed in its manufacture. Section 3(d) mandates that a substance or a composition must be novel, should involve an inventive step and should be capable of industrial application, whereas, swiss-type claim format deviates from the rule of absolute novelty. The discovery of previously unrecognized useful property of a drug is not considered novel in India and hence is not patentable. This section of the act makes it clear that Swiss-type claims are not accepted for patent protection in India. An improvement made to a known substance does not qualify for patent protection in India.

The Act considers salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations and other derivatives of known substance to be the same substance, unless they differ significantly in properties with regard to efficacy. In India only a new chemical entity or a new medical entity is granted protection. Formulations, such as, combinations of pharmaceuticals, changes in dosage form, new use of a known medicament, etc, are considered not patentable as there is lack of inventive step.

The Basis for Exclusion

The basis for the exclusion of ‘new use of already known chemical entity’ from patentability is that it might lead to Evergreening of that chemical entity. Through Evergreening companies try to secure patents on large numbers of complex and often highly speculative patents through minor modifications, when the original patent over the active compound of a brand-name drug is due to expire. These subsequent patents cover different forms of the substance or minor variation and everything from aspects of the manufacturing process to tablet color, or even a chemical produced by the body when the drug is ingested and metabolized by the patient.

By evergreening the multinational pharmaceutical companies are retaining profits from their blockbuster drugs for long as possible. Pharmaceutical giants in countries like US adopt the swiss-type claim format as a monopolization strategy to evergreen their patented drugs.

Conclusion

The Indian Patents Act mandates that for being patentable a substance or a composition must be novel, should involve an inventive step and should be capable of industrial application, whereas, swiss-type claim format deviates from the rule of absolute novelty. As per Section 3(d) of the Act, to obtain a patent for the second and subsequent use of a medicament, the therapeutic efficacy must be enhanced or at least a new reactant must be employed in its manufacture.

The rigid approach of Indian patent system towards exclusion of swiss-type claim format has made the pharmaceutical industries disinclined towards further improvement of a known drug or discovery of new therapeutic use of a known substance. It is apparent that pharmaceutical research does not halt on patenting of one pharmaceutical activity, due to ongoing research the same drug may be found to have other beneficial properties which was previously unrecognized. Therefore, from the viewpoint of a pharmaceutical company the exemption of Swiss-type claim format in India is unwelcoming.