The Korean patent term extension (PTE) system is comparable to the provision of supplementary protection certificates (SPC) in Europe. Like SPCs, the PTE system was introduced to compensate the patentee for commercialization delays due to clinical studies for safety and efficacy of drugs, testing for efficacy of pesticides, and regulatory review of the documentation requirements for marketing authorization (MA). 


Patents eligible for PTE are valid patents for substances, processes, uses, and compositions, and only one extension per patent is granted, for a maximum period of five years. Different from the SPC filing term of 6 months from the MA date, in Korea, the PTE application should be filed within 3 months from the MA date. However, PTE applications may not be be filed within 6 months before the expiry of the patent term, since generic competitors may expect the original patent to expire and already be preparing to bring their cheaper generic drugs to market.  

Among other requirements, to be eligible for PTE, the relevant subject matter must be a new substance for which the first MA has been granted. According to a revision of the Enforcement Decree of the Patent Act in 2013, only new substances are eligible for PTE.  

Term & Scope

In the U.S., the FTA calculates the extendable term and informs the USPTO and the patentee. However, the Korean Intellectual Property Office does not calculate and award PTEs automatically; the patentee must file an application for PTE and calculate the length of extension for which they are eligible. Extension is generally based on the length of the domestic clinical studies period plus regulatory review period, but any period of delay attributable to the patentee would be deducted. A March 2017 Supreme Court decision provides clear guidance on what constitutes a “period of delay attributable to the patentee.” For example, if one division of the Ministry of Food and Drug Safety (MFDS) requests a patentee to file supplementary documents concerning safety-efficacy data within a designated period for response while another division is still conducting examination, the response period cannot be considered to be time solely attributable to the patentee. 

Regarding the scope of extended rights, Article 95 of the Korean Patent Act stipulates that PTE covers only patented inventions related to an approved product and any use approved for the product. Accordingly, the scope of extended rights is limited to a product covered by MA, rather than the scope of the original patent, despite PTEs being granted for the entire scope of the patent claims.  

2019 Supreme Court Ruling

In 2019, the Korean Supreme Court made a notable ruling concerning the scope of extended rights (Case Ref. 2017Da245798). In this case, a major point in question was whether or not modified salts are within the scope of extended patent rights. The Supreme Court reversed an earlier Patent Court decision and recognized, for the first time, the enforceability of an extended right against a competitor’s product comprising a different salt.  

In particular, the Court pointed out that the literal wording of Article 95 is that an extended right covers a “patented invention” related to the approved product, not the “approved drug” only, and stated that the primary consideration in determining the scope of a drug patent under term extension is whether the active ingredient, the therapeutic effects, and use of a product in question are identical to those of the approved drug, and whether the modified salts are readily interchangeable by one skilled in the art.  

Based on such reasoning, the Court found that the two products in question have the same therapeutic effects derived from the identical active ingredient, i.e., solifenacin; and a person skilled in the art would easily replace succinate with fumarate. 

We are of the opinion that the Supreme Court considered the purpose of the PTE system, which is to ensure patent protection to promote research and the development of new drugs, since if the scope of protection is granted for approved products only, it would be very easy to circumvent the protection conferred by the PTE, rendering the PTE worthless. 

The PTE system is a matter of policy concerned with balancing conflicting interests. Therefore, further thought should be given to the balance between generic market entrants and incentives for brand-name pharmaceutical innovators.