It has been published by Rachit Garg.
Table of Contents
A patent for drug repurposing (or drug repositioning) is a case where the patent is claimed for the discovery of new use or new property of a known drug or medicinal substance. Rather than embarking on a wholly new process of developing a drug, the repurposing of drugs does the work of redirecting the known medicinal substance towards new therapeutic use or treatment of a medical condition not contemplated in the previously patented substance. The repurposing of drugs has some advantages in developing medicines for the treatment of diseases in a more convenient way, having ready access to relevant experimental data relating to bioavailability, toxicities, established protocols and dosing regimes. These are data which are “in excess of what can be derived from Phase- I clinical trials of new drugs, particularly for first in a class of drugs”. Due to this advantage of the ready availability of clinical data, drug repurposing has been considered a mode of faster production of safe drugs for the treatment of diseases avoiding the huge cost of research and development expenditure in it, and thus serving the demand of the medical field and national interest on health protection. Upon such considerations, the patent claim of pharmaceutical companies to repurposed drugs has found the attention of government policymakers and legislators, researchers, investors, etc. But the patentability criteria of traditional patent jurisprudence (e.g. considerations of novelty, inventive step, and technical application) pose difficulty in obtaining patents for repurposed drugs. Equally important along the line of the said tests, there are certain policy issues of the Government concerning the grant of patent to the said invention. This article discusses the principles of patent jurisprudence, country-specific differing legislative approaches, government policy, legal practice and modern development in respect of patents to repurposed drugs.
Principles and policy issues in patent law that pose difficulty in granting patents to repurposed drugs
The traditional jurisprudence of patent law rests upon three basic patentability criteria, namely, novelty, inventive step, and technical advantage. When it comes to novelty, significance rests on whether the invented product or process is new or not. While this patentability criterion is easily crossed over by the inventors, it is the criteria of the invention being an ‘inventive step’ that usually becomes a hurdle for the inventors. ‘Inventive step’ for patentability is a quality that distinguishes the claimed invention from the prior art (or knowledge), belonging to the same field. Alongside an invention possessing an inventive step, it must also be non-obvious. Non-obviousness signifies that when the invention becomes known to people belonging to the same field as the inventor, the invention does not appear to be an obvious outcome with no unique traits attached to it. The Indian Patent Act, 1970 under Sections 2(1)(j) and 2(1)(ac) has incorporated these patentability criteria. Thus, the dominating patentability principles prevailing under patent jurisprudence can be summarised as below:
- It must be “new”, that is to say, it must not have been anticipated in the existing knowledge or discovery;
- It must involve an “inventive step” to such a level that it is not obvious to a person having ordinary skill and knowledge in the relevant field.
- It must be capable of producing technical advantage, i.e. it can be put to “industrial application”, thereby being capable of being made or used in industry.
Taking into account the derivative effects of the said principles, the granting of a patent to repurposed drugs poses difficulty in terms of resolving important legal issues, such as:
- Whether the claim of the invention having a “new use” or “is a new discovery” of the known patented substance is further patentable or not,
- Whether such a grant of patent is in nature an extension of an existing patent.
Upon these central issues, the practice of patenting repurposed drugs differs from one country to the other. While grant of patents to repurposed drugs has been recognized in several jurisdictions such as the USA, Australia, China, Europe, etc (provided that certain patentability criteria set by the nations’ respective laws are fulfilled), on the contrary, there are countries that do not grant patents to repurposed drugs, such as India, Indonesia, Argentina, etc. The latter series of nations have provided their own set of interpretations when it comes to the patentability criteria mentioned previously. Further, government policies of these nations also contribute to the denial of patent grant to repurposed drugs, namely:
- Preventing monopoly in the market.
- Providing divergent scope for research and development of generic medicines by local players in the market.
- Striking a balance between the competition of foreign industry vis a vis local industry in case of the medicinal field.
The “Swiss-type use patent” is practised for repurposed drugs
What is a “Swiss-type” use patent
Generally, patent laws across nations prohibit inventors from claiming a patent in the “method of treatment” of a disease. It follows that the patent claim on repurposed drugs, even in the jurisdictions where allowed, cannot be drafted in the form (eg “Use of X to the treatment of disease Y”), since it will be barred by being a “method of treatment claim”. Earlier to evade the said restriction of patent law, patent attorneys used to draft patent claims in a form known as “Swiss-type claim”. This claim type is a method of drafting a claim obtaining similar claims like a claim for patent on “medicinal use”, thereby avoiding the claim being placed directly as “the treatment of a medical condition”. As per the “Swiss-type claim” format, the claim will now be placed as a method or process of manufacturing medicine to be used in the treatment of a new medical condition (for example, “use of substance X for the manufacture of medicine to treat the Y”).
The name Swiss-type claim comes from its first recognition by the Swiss Federal Intellectual Property Office (FIPO) publishing “Legal Advice”, dated 30 May 1984” in the EPO Patent Journal no. 11/1984 in respect to a practice developed in Europe to claim patent to repurposed drugs. In the context of legal bar to the grant of patent in case of “method of treatment of medical condition”, the said Swiss patent authority cleared the way for getting second use patent of known drug suggesting a “claim format” by issuing the said official legal advice as provided hereunder.
The Swiss Federal Intellectual Property Office’s (FIPO) legal advice in respect of the second use patent to therapeutic treatment claim (dated 30 May 1984)
“A claim for the “use of compound X to treat … (indication) …” is inadmissible under Swiss Law. Limited claims directed to the “use of a compound … to produce agents against …” are admissible even where they relate to a second (or subsequent) medical use of a known medicament. Details concerning the formulation of a medicament (e.g. labelling, packaging or dosage) may be included in a patent application´s description.”
Thus according to the said FIPO notice, the Swiss-type claim for the repurposed drugs stood in brief like this,
“use of compound X in the manufacture of a medicament for the treatment of medical condition Y”.
However, even if the second use patent is allowed for an invention (e.g. repurposed drugs), it has to mandatorily pass the basic patentability criteria establishing novelty, non-obviousness, and industrial application. With this dominating three basic patentability criteria in the patent jurisprudence, the grant of a patent for repurposed drugs faces different levels of difficulties in different jurisdictions depending upon the actual text of patent legislations in such jurisdiction, the legislations which are backed by the country-specific government policy given considerations to variety issues and national concerns, such as– industrial, commercial, public health protection, economic and social context, etc.
The earlier judicial decision that provided for grounding the Swiss-type claim receiving legal recognition
The judicial principle previously developed recognized that, the “second use claim” for the manufacture of a medicament for the treatment of a new medical condition, although in effect involved the second (or further) use of a known pharmaceutical composition would be patentable provided that it passed the test of novelty, non-obviousness, and industrial application. In connection to the judicial development of this principle, as an attempt of rationalising the traditional patentability principles with the need to grant of “second use patent” can be referred to the most cited case, General Tire & Rubber Company v The Firestone Tyre and Rubber Company and Others (1972) (hereinafter mentioned as “the General Tire” case).
The summary fact of the case
An appeal was filed before the Supreme of Court of Judicature, UK, from the judgement given on 31st July 1970 by Graham, J. in a proceeding in which the respondent (plaintiffs) sought a remedy against the infringement of its patent No. 737,086 (priority date 20th November 1950) and the appellant (defendants) sought its revocation. The primary issue that arose, in this case, was that the impugned patent application was devoid of patentability criteria in terms of ‘anticipation’, ‘obviousness’ and ‘absence of any inventive step’, thereby being in violation of Sections 32(1)(e), 32(1)(f) and 32(1)(i) of the Patents Act, 1949.
The Supreme Court of Appeal had observed while dismissing the appeal, that,
- The invention claimed was not anticipated by any of the cited documents,
- That it was not obvious, and
- That the objection of ambiguity was not established.
The test for determining the existence of novelty in subsequent inventions has been laid down by the court of law in this case. The fact that the prior art provides a direct lead of being similar to the claimed invention ipso facto eliminates the latter from the ambit of claiming patent protection. The case had concluded that “to anticipate the claim, the prior publication had to contain a clear and unmistakable direction to do what the patentee claimed to have invented”.
Subsequent replacement of Swiss-type claim: global context
Subsequently to the above-stated judicial recognition, the practice of “second use patent claim” got its firm footing by its later adoption in a decision of the Enlarged Board of Appeal of the European Patent Office dated 05 December 1984. This decision was made in connection to a Case Gr 05/83 which was referred to it by the Technical Board of Appeal for Chemistry of the European Patent Office in accordance with Article 112 of the European Patent Convention, 1973 (EPC 1973) to resolve a question of law on the application of “Swiss-type use claim”. The question of law raised was that, “Can a patent with claims directed to the use be granted for the use of a substance or composition for the treatment of the human or animal body by therapy?”
The Enlarged Board of Appeal had opined that decision in favour of Swiss-type claim can be passed after taking reference from the adoption of practice “use claims” by the Swiss Federal Intellectual Office, wherein “a claim to the use of an active ingredient for the manufacture of a medicament ready for administration could be allowed even where it related to the second (or further) application for a known pharmaceutical composition”.
The practice of “Swiss type claim” has now been abolished in Europe by the above stated decision given in the case G 05/83 of the European Patent Office (EPO) which prescribed the new form of drafting the patent claim in the second use of patented substance, i.e. claims “where the subject-matter of a claim is rendered novel only by a new therapeutic use of a medicament”. This simplified new EPC form for second use patent, states that, “Substance X for use as a medicament” or “Substance X for use in the treatment of disease Y”(hereinafter referred to as “the EPC-2000 Patent Claim Form”). However, such a claim must establish an “inventive step” over any prior art disclosing the use of “known substance” as a medicament.
The reason for abolishing the earlier practised “Swiss-type” claim is explained in the European Patent Examination Guideline stating that, “a claim to a particular physical activity (e.g. method, process, use) confers less protection than a claim to the physical entity per se (G 2/88, Reasons 5.1)”.
Here, attention is to be paid to the claim format, “Use of substance or composition X for the treatment of disease Y..”, which is not patentable under EPC since it will be regarded as relating to a method for treatment explicitly excluded from patentability under Article 53(c) and therefore will not be accepted. Rather this should be converted to the direct claim of patent to the ”medicinal substance” itself to be used in treating disease (instead of claim to the “use of the medicinal substance for treatment”).
After the abolition of the practice “Swiss-type patent claim” by EPC 2000, the UK also abolished it by issuing the patent practice guideline dated 25 November 2021 titled as “Examination guidelines for patent applications relating to medical inventions in the Intellectual Property Office” (in guideline No. 2 and 3). The said guideline also exemplified the effect of different claim formulations on patentability after EPC 2000, as have been provided in a table as below:
|A||Use of product X for the treatment of asthma||No||53(c)|
|B||1. Product X for use as a medicament[X known as e.g. herbicide]2. Product according to claim 1 for use in the treatment of asthma||Yes(even if X is a known product, but its use in medicine is not known)Yes||54(4)|
|C||Product X for use in the treatment of cancer*||Yes(even if case B is prior art, provided that such a claim is inventive over B and any other prior art)||54(5)|
|D||Product X for use in the treatment of leukaemia*||Yes(even if cases B and C are prior art, provided that D is inventive over B and C and any other prior art because leukaemia is a specific type of cancer)||54(5)|
(Note: Previously the corresponding Swiss-type claims for cases C and D (required under EPC 1973) would be “the use of Product X for the manufacture of a medicament for the treatment of cancer/leukaemia.)
Indian position for patent to repurposed drugs
In India, neither the patent claim in the form “Swiss Type” to use a known medicinal substance in the manufacture of a medicament (i.e. the process patent) is permitted, nor in the form claim to “medicinal product itself” in its repurposed use is possible. The relevant patentability bar arising under the Indian Patent Act, 1970 (amended 2005) is discussed below.
Indian Patent Act, 1970 defines the term ‘invention’ as “a new product or process involving an inventive step and capable of industrial application” (Section 2(1)(j)).The term “inventive step” is defined as “a feature of an invention that involves technical advantage as compared to the existing knowledge or having economic significance or both” of such a nature that it is “not obvious to a person skilled in the art” of the relevant field (Section 2(1)(ja)). The term “capable of industrial application” has been meant to indicate such quality of the invention by which it is “capable of being made or used in an industry” (Section 2(1)(ac)). It is necessary to note that while for any invention seeking patent protection, abiding by patentable criteria is a must, not falling under Sections 3 and 4 (non-patentable inventions), stands equally relevant. Pertinent to the subject matter of this present study, here it is worth mentioning that Section 3(d) of the 1970 Act excludes inventions which represent the mere use of known substances or already existing substances.
The collective impact of these provisions operates as a hindrance for the grant of patent in repurposed drugs. It is noticeable that the “inventive step” as required under the Indian patent law for patentability to an invention is of a higher degree of expectation which goes beyond the “mere discovery of new property or new use of known substance or process” being that it must attain the quality of new product or be made of applying at least a new reactant to the known process of manufacturing.
Novartis Ag vs Union of India & Ors (2013)
The leading case in the discussed matter, Novartis Ag vs Union of India & Ors (2013), remains a landmark judgement dealing with therapeutic efficiency and interpretation of Section 3(d) of the Indian Patents Act, 1970. The appellant, Swiss company, “Novartis AG” claimed a patent to its drug Glivec, in its beta crystalline form. The appeal was filed before the Supreme Court of India against the decision of denial of a patent by the Intellectual Property Appellate Board (IPAB). It was alleged by the appellant that the drug is the formulation of “beta crystalline”, a developed form of a chemical compound called Imatinib Mesylate which has been used as a therapeutic drug for the treatment of chronic myeloid, leukaemia.
It is interesting to note that in 2005, Madras Patent Office had rejected the patent application for “Glivec” by Novartis on grounds that the alleged drug was not only anticipated by prior publication, but also failed on satisfying requirements of novelty and non – obviousness as laid down by the Patents Act, 1970. Further reasoning that the claimed invention fell within the ambit of Section 3 (d) and that the new drug in no way contributed to enhanced efficacy of the existing one, the patent application stood dismissed.
In upholding rejection of the patent as was decided by the Madras Patent Office, the Indian Supreme Court held that the invention does not involve inventive steps to overcome patentability criteria as required under Section 3(d) of the Indian Patent Act, 1970 (as amended in 2005). The Court after paying intensive attention to the legislative history to find the purpose of enacting amended Section 3(d) and it’s true purports, commented that taking into consideration the collective impact of Sections 2(1)(j), 2(1)(ja), 2(1)(ac) and Section 3(d), the terms ‘invention’ and ‘patentability’ are to be construed having two different meanings.
Under Indian law, an invention, even if it is new, must further pass the test of patentability barrier provided under Section 3(d). Interpreting Indian patent law the Court held that to overcome the patentability barrier of Section 3(d), the appellant was obliged to show that, “the enhanced efficacy of (its claimed invention) the beta crystalline form of Imatinib Mesylate over Imatinib Mesylate (non-crystalline). There is, however, no material in the subject application or in the supporting affidavits to make any comparison of efficacy, or even solubility, between the beta crystalline form of Imatinib Mesylate and Imatinib Mesylate (non-crystalline).”
With the said findings, the Court refused to grant a patent to the appellant holding that its invention is simply an amended version of the known compound without producing any new medicine and showing any enhanced technical advantage over the existing medicine. Its patentability is thus hit under Section 3(d) of the Patent Act, of 1970. Though refused the patent in India for the said invention, it is pertinent to mention that the appellant’s medicine Glivec, had been patented in nearly 40 countries including USA, Russia and China.
The decision of the Apex Court in this landmark case hints on the weightage given to India being the hub of generic medicine thereby negating the evergreening of patents with an intention to restrict monopoly ruling in the Indian market. Prior to the amendment in 2005, the Patent Act 1970 was only in favour of process patents (patenting of the process through which the medicine has been made), when it came to drugs and chemical substances. Following the 2005 Patent Amendment Act, product patents had entered the Indian scenario. India continues to uphold the interest of the public over monopoly players and this judgement is a clear reflection of the same.
Patent to repurposed drugs is important in terms of its contribution to the necessity of the medical field. The question of granting a patent to the repurposing of drugs has to be answered by drawing a balance between protecting the statutory promise of monopoly granted to the patent holder for the statutory term in the exploitation of invention and mitigating the adverse effect of granting patent and further patents to an invention, granting which produces the obstructive effect or the narrowing down effect upon the subsequent research and development in the relevant patent area. Besides that, the national policy determination varies depending upon its special economic and social context. This is an area in which patent law has much to do to find appropriate legislative provisions drawing the said balance thereby resolving growing issues.
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