Unique Requirements for Patentability in Korea – Pharmaceutical Composition and Medicinal Use Inventions

Medicinal inventions refer to inventions whose component is a medicine and where the use of the medicine is directly or indirectly related to the human body. Under Article 50-2(4) of the Pharmaceutical Affairs Act, medicinal inventions that can be registered on the Drug Patent List are:

In the field of medicine, medicinal use inventions are distinct from pharmaceutical compositions, and Korean court precedents have established unique legal principles for specification description requirements for medicinal use inventions.

The Korean Supreme Court defines a medicinal use invention as “an invention providing a new use that exhibits medicinal efficacy based on the discovery of a previously unknown characteristic of a specific pharmacological effect of a medicinal substance (see Supreme Court Decision No 2014Hu768, rendered on 21 May 2015). Because the pharmaceutical use of a specific substance is a component of a medicinal use invention, the pharmacological effect must be specifically described in the specification with experimental examples containing pharmacological data, or the equivalents thereto (see Supreme Court Decision 2003Hu1550 rendered on 23 December 2004, etc).

The Korean Supreme Court has consistently ruled that, for a medical use invention, which requires description of pharmacological effect, absent any special circumstances where the mechanism of the pharmacological effect described in the specification was already known before the filing of the patent, the pharmacological effect must be described either through experimental example showing pharmacological data or in sufficiently detailed description that is equivalent to such experimental example, to consider the description requirement as fulfilled (see Supreme Court Decision 2001Hu65 rendered on 30 November 2001, 2013Hu730 and 727 rendered on 23 April 2015, etc).

Although court decisions requiring strict specification requirements only for medicinal use inventions have been criticised, the Korean Supreme Court has not changed the position. Foreign patent applicants should be mindful of these different, stricter requirements in Korea, as there can be serious consequences for not including pharmacological data in the specification.

Pharmaceutical compositions are a type of product invention, so the Korean Supreme Court applies the general specification description requirements applicable to product inventions.

Regarding the specification description (enablement) requirements for product inventions, the Supreme Court has consistently held that “For product inventions, 'practicing' the invention refers to the act of producing and using the product. So if a person of ordinary skill in the art (POSITA) with the technical level at the time of filing a subject patent application could produce and use the product based on the detailed description in its specification without excessive experiments or adding special knowledge and could sufficiently predict the effect of the subject invention, even if it is not proven by specific experiments, the specification description requirements are fulfilled” (see Supreme Court Decision 2014Hu2061 rendered on 26 May 2016 etc).

The Korean Intellectual Property Office (KIPO) stipulates that any medicinal invention should, in principle, be described in the form of a composition (eg, a pharmaceutical composition for treating disease B using compound A as an active ingredient). This makes it difficult to practically distinguish pharmaceutical compositions from medicinal use inventions based on their descriptive format of claims, resulting in the problem of expanding the scope of medicinal use inventions. A combination drug invention, a formulation in which two or more active ingredients are used in combination, is one such example.

Combination drug inventions can be divided into (i) an invention whose technical characteristics lie in the novel “combination of substances” per se and (ii) an invention whose new use has been invented for a known combination. However, the KIPO has uniformly applied the strict specification description requirements of medicinal use inventions to combination drug inventions.

Moreover, Korean courts also seem to make decisions on the premise that combination drug inventions fall under medicinal use inventions. For instance, in the precedents on combination drug inventions such as Supreme Court Decisions 99Hu2396 (13 November 2001) (Ondansetron and Dexamethasone), 2005Hu1417 (30 March 2007) (Amlodipine and Atorvastatin), 2006Hu2523 (26 July 2007) (Taxotere and Cisplatin or Carboplatin), etc, courts rejected the patentability of these inventions for failing to meet the specification requirements for medicinal use inventions.

In these decisions, the court did not specifically hold that the description requirements for medicinal use inventions should be applied to combination drug inventions. Rather, the courts seemed to find each invention as a medicinal use invention under the relevant facts and applied the strict description requirements. Therefore, it is necessary to monitor how courts will decide on the specification description requirements of combination drug inventions.

It is necessary to be very cautious, especially when filing an application for medicinal use inventions in Korea because, absent special circumstances, pharmacological data must be described in the specification. Moreover, although medicinal use inventions and pharmaceutical compositions are clearly distinguished concepts, the scope of the medicinal use invention is being expanded and their distinction is blurred because they are required to be claimed in practically the same format of claims. As for combination drug inventions, it remains to be seen how Korean courts will determine the specification description requirements of combination drug inventions in the future.