19 March 2024

Second Medical Use-Patents

S&A Law Offices


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The idea that previously discovered chemicals and compositions may be used to discover novel functions, capacities, or medicinal applications is certainly intriguing.
India Intellectual Property
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The idea that previously discovered chemicals and compositions may be used to discover novel functions, capacities, or medicinal applications is certainly intriguing. Patents can frequently be used to protect these, however not all states allow the protection of a known substance's new medicinal uses. For instance, in India, the discovery of new qualities from known compounds is not regarded as "inventive," so a new use for a recognized chemical is not covered by patent protection.

There is, however, some hope for applicants hoping to patent novel applications for already-approved medications in India, so long as the compositions are said to be synergistic combinations and bolstered by data disclosure in their specification. Applicants will be better able to develop claims in an application and increase the likelihood of a successful grant if they understand how protection for new medical uses of known substances or second medical uses can be pursued in India and how to draft effective claim forms that are more likely to be accepted by the government.

Provisions for examination:

In India, an existing substance cannot be patented for a novel medical purpose. Claims that describe a novel use of a well-known substance or method are not patentable in India. Furthermore, the Patents Act prohibits the use of methods of treatment. There isn't a draft, proposal, or conversation regarding changing any of the clauses.

  • Section 3(d)precludes patenting of "...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". The applicant will have to demonstrate to the satisfaction of the controller that the set of claims that immediately fall under this exclusion pertain to a novel composition, procedure, or new form of a known substance that enhances the known efficacy of that substance. A patent would not be granted for any application of a known method, tool, apparatus, or material.
  • Section 3(e)precludes patenting of "a substance obtained by a mere admixture resulting only in the aggregation of the properties of the components thereof or a process for producing such substance".
  • Section 3(i)precludes patenting of "any process for the medicinal, surgical, curative, prophylactic diagnostic, therapeutic or other treatment of human beings or any process for a similar treatment of animals to render them free of disease or to increase their economic value or that of their products".

An invention must pass the efficacy test. Section 3(d) determines whether a new use or new form of a known compound/composition is patentable unless the new compound/composition increases the therapeutic efficacy of the existing compound/composition. Existing compound/composition derivative(s) are considered identical to existing substance(s), except where a significant property difference results in an equivalent difference in efficacy.

If the Applicant decides to amend the claims, one must ensure that the amended claims shall be supported from the original scope of protection sought under the disclosure, which most Controllers often interpret as the amendments should be within the scope of protection sought under the original claims.

"If the functional interaction between the features achieves a combined technical effect which is greater than the sum of the technical effects of the individual features, it indicates that such a composition is more than a mere aggregation of the features," state the IPO Guidelines for Examination of Patent Applications in the field of Pharmaceuticals.

"Synergy" in this sense refers to an unexpected result or effect of the combinations, prior art bias, etc., which typically highlights the inventiveness of the work. Synergy in chemical composition claims refers to therapeutic activity; for instance, compound 'A' in the claimed range combined with excipients that are deemed safe by pharmaceuticals offers therapeutic activity. To illustrate the synergistic effect of compositions, experimental data must be presented. The experimental data may be submitted with the full specification when it is filed, or it may be submitted in response to a question the Controller may have raised while the application was being investigated. However, the filed specification must provide adequate support for such experimental data. It is important to make sure that no additional data is submitted that does not fit within the disclosed specification's scope of contents.

Synergy and Second Medical Use:

Section 3(d) objections are certain to arise when an applicant files an invention pertaining to a second medical use of substances that are already known. Including a claim that the subject application relates to section 3(e) as it relates to a combination or composition of known substances rather than section 3(d) is the simplest method to get around a section 3(d) objection.

Drafting a formulation, composition, or combination claim has been a common tactic used by pharmaceutical invention applicants to get their applications out of section 3 scrutiny. In these situations, the outcome is referred to as "synergistic" when the combination claim's overall effect results in an unpredictable change from the functions of the individual derivatives.

Section 3(e): If the claimed composition is a mere aggregation of the properties of its constituents, the same is not regarded as in invention under Section 3(e). To overcome this objection, the Applicant needs to establish to the satisfaction of the Controller that the claimed composition exhibits a property which is different from mere aggregation of properties of its constituents, in other words, the constituents shall show some synergistic effect resulting in a final property which is not a mere aggregation of constituents' respective properties. In order to establish such synergistic effect Applicant should primarily rely upon the complete specification as filed, and further experimental data can also be produced to corroborate the synergism.

It is to be noted that the "test of enhanced efficacy" is not with respect to Section 3(e), however the same is applicable while assessing claims in light of Section 3(d). The experimental data demonstrating enhanced therapeutic efficacy will be helpful in contesting/overcoming the objection under Section 3(d).To overcome such objection, Applicant is required to establish to the satisfaction of the Controller that the claimed compound is not a mere new form of a known compound OR show by way of experimental data that the new form of known compound has enhanced efficacy or enhanced therapeutic efficacy for inventions relating to medicine/pharmaceuticals.

The concept of showing the synergy between constituents of the claimed compound and eventually showing new property or outcome of the claimed compound vis-à-vis mere aggregation of properties of its constituents is more applicable to overcome objections under Section 3(e) of the Act. Further, the concept of synergistic effect can also play a corroborative role towards establishing enhancement in known efficacy while attending to Section 3(d) objection. Therefore, if claims are reformulated to composition claims, and the same can be shown to be novel, inventive – and/or if found to be a new form of known compound attracting Section 3(d), one would be able to show enhance efficacy by way of experimental data, the chances to secure a patent in India would considerably improve.


The first classic example of medicine which found its second use was aspirin the well-known out off the shelf drug for relieving head ache which was later found to be useful as Anticoagulant/Anti stroke/anti-ischemic drug. There are dozens of instances of existing medicines being developed for new uses. For instance, Sildenafil citrate primarily used for Heart and vascular disease later marketed as drug for Erectile dysfunction. Similarly, Finasteride meant for treatment of prostate disorders was also found to be effective in the treatment of androgenetic alopecia. Thalidomide found second use to relive morning sickness in pregnant women but it's first use was for respiratory infections. Further, it was found to be useful in the treatment of leprosy and for cancer. Other known drug for second use are Daclizumab [transplant rejection] now used in treating certain types of multiple sclerosis; Aclasta [osteoporosis] ; Zometa [bone cancer] ; Ravatio [pulmonary Hypertension].


The primary goal of refusing a patent for a new use is to prevent the issuance of two patents for the same invention. However, the IPO practice is not entirely clear when it comes to determining whether the prohibition against double patenting applies in connection with claims drafted as use claims. Occasionally, it clearly allows purpose-related product protection for medications already known to exist in combination, provided that these combinations work well together or yield unexpected outcomes. This demonstrates that there is no clear and convincing reason to reject the applicant's rightful interest in pursuing newly drafted use claims that are part of purpose-limited product claims.

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.

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