Saturday, November 05, 2005

Patentability issues: New medical uses of known substances

This article was published in pharmabiz on Wednesday, March 16, 2005.

Under the Patents Act, 1970 patents are granted only for inventions. For a thing or a substance to qualify as an inventions it should satisfy the three prerequisite conditions of novelty (the invention should be new), non-obviousness (the inventions should contain an inventive step) and should be capable of industrial or commercial application. The new ordinance has brought in patent protection for food, medicine and drug products. It is commonly understood that the patent would be for the invention of the product per se. To what extent medical uses of known substances would qualify for patent protection is an issue that the Patent Office will soon be called upon to decide.

The focus of pharmaceutical research has shifted in the recent past from the invention of new drugs to finding new uses for known substances. This fact is evident from the low number of new drugs that are clinically tested and approved for marketing in any given year. Pharmaceutical companies are now keen on discovering new properties or uses of known drugs. An oft quoted example involves the drug aspirin which was originally known to have only analgesic properties but later novel properties like thinning of blood were discovered.

A product patent would provide protection not only over the thing itself but also over all subsequent uses. Traditionally, the British approach treated a claim to a 'product for a particular use' as a claim to the product itself. Any novel use at a later time could not qualify for protection under the earlier patent. The product would lack novelty even if the product had been put to a different use. This approach did not recognise 'novelty of purpose' as a ground for the grant of a patent. This rigid approach has now been relaxed to include second and subsequent medical uses. The European Patent Office and the English courts have begun to recognise novelty of purpose in all fields of technology.

Novel medical uses

The question as to whether the discovery of a new advantage of an old thing used in an old way would be entitled to a patent protection under the new patent ordinance will have far-reaching implications on the pharmaceutical industry. The insertion of the word 'mere' in section 3(d) has opened new possibilities for claiming 'novelty of purpose' as per the Act. Section 3(d) of the Patents Act, 1970 reads as follows:"3.What are not inventions - The following are not inventions within the meaning of this Act - (d) the mere discovery of any new property or mere 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;"It could be argued that the inclusion of the word 'mere' has widened the scope of patentability so as to include novel medical uses.

Exclusion of methods of medical treatment

Most countries regard the method of treatment of human and animal body as non-patentable. The exclusion of methods of treatment caused concern to the pharmaceutical industry which has by now shifted the focus of its research to discovery of new uses/new benefit from old substances, from the discovery of new substances. As a concession, pharmaceutical industries were entitled to claim patent for a new use of a known substance in many countries, particularly, United Kingdom where section 2(6) of the UK Patents Act, 1977 provides thus:

"the fact that an invention consisting of a substance or composition for use in a method ofmedical treatment 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."

The above provision creates a statutory exception to the traditional British view that the mere discovery of purpose could confer novelty of an invention. The provision confers novelty through a new purpose, i.e., new pharmaceutical use of a known substance, even though the substance itself is known to be a part of the state-of-the-art.

Second and subsequent medical uses

Originally it was believed section 2(6) would apply only to the discovery of the first medical use of known products. A plain reading of the provision would clearly exclude second and further medical uses as they would lack novelty. The scope of a similar provision under the European Patents Convention (54(5)) was considered by Enlarged Board of Appeal of the European Patent Office in Eisai / Second Medical Indication (Eisai G5/83 [1985] OJEPO 64). Emphasising that exception to patentability should be constricted narrowly, the Board held that Article 54(5) also applied to second and subsequent medical uses. Such claims would be upheld, the Board opined, provided that the claims were drafted in a style known as the "Swiss form of claims."The status of second medical use was considered by the UK Patents court in Wyeth's Application [1985] RPC 545. One of the claims in this case was drafted in the Swiss form. The examiner refused to grant such a claim, but on appeal, the Patent Court allowed it. There are no provisions in the Indian Act similar to section 2(6) of the UK Act or article 54(5) of the European Patent Convention. But it is pertinent to note that provisions very similar to section 3(d) of the Indian Act exist in other countries which states that a "mere new use for a known substance" will not qualify for a patentable invention. It would only be a matter of time that express statutory provisions providing for patent protection for new use of a known substance would be introduced in Indian law in keeping with the global trend. Till then, the Patent Office could be urged to consider patents for new use of a known drug as the Indian Act excludes only a mere new use for a known substance. As such there is no prohibition in granting patents for the use of the substance in any method which does not form part of the state-of-the-art.