Korean Patent Court Confirms for the First Time That the Scope of an Extended Patent Is Not Limited to the First-Approved Indication

Under Korean law, the scope of a patent during its patent term extension (“PTE”) period is restricted to the “specific use” of the original approved product on which the PTE is based, in contrast to some foreign jurisdictions where the patent scope during the PTE covers all uses. In Korea, the scope of “specific use” under Article 95 of the Patent Act has been actively litigated in recent years, but this case represents a significant milestone as the first ruling by a Korean court on this subject.

The case involved a dispute concerning K CAB® (active ingredient: tegoprazan), a potassium-competitive acid blocker (“P CAB”) launched by HK inno.N Co., Ltd. under an exclusive license to the compound patent (Korean Patent No. 1088247, the “Compound Patent”) for the tegoprazan compound owned by RaQualia Pharma Inc. Dozens of generic companies contested the Compound Patent and sought market entry timed to the pre extension expiry date of December 6, 2026. Under this ruling, however, exclusive rights are maintained until August 25, 2031, the extended expiry date (total extension: 1,723 days).

The generics’ central argument was that the “specific use” must be confined to the “first approved indication(s)” under the Pharmaceutical Affairs Act. Accordingly, the case presented the following two issues:

Issue 1: Whether “specific use” should be strictly limited to the first approved indication under the Pharmaceutical Affairs Act, or be determined based on a case-by-case analysis of the patent’s technical contribution.
Issue 2: If Issue 1 is resolved in favor of the technical contribution analysis, whether the subsequently approved indication shares identical therapeutic effect and medicinal use as the first approved indication.

The Intellectual Property High Court (the “IP High Court”) accepted Kim & Chang’s position that the “specific use” under Article 95 should not be limited to the first approved indication under the Pharmaceutical Affairs Act, rejecting the generics’ arguments.

1.	“Specific Use” in Article 95 Is Not Limited to the First Approved Indication In particular, the IP High Court rejected the generics’ arguments for the following reasons:

The PTE system seeks to compensate for the time and effort invested in the development of new drugs. While a PTE application is examined based on the first product approval, Article 95 of the Patent Act clarifies that the subject matter of a PTE is not “the drug that received the first product approval,” but rather “the patented invention” itself.
The Patent Act and the Pharmaceutical Affairs Act serve distinct purposes. That is, under the Pharmaceutical Affairs Act, product approval requires detailed descriptions of the efficacy and effects (indications), including specific disease names, symptoms, patient history and severity, all supported by proven efficacy and safety data from clinical trials. In contrast, under the Patent Act, medical use can be broadly described in terms of the effects or target diseases for diagnosis, treatment, alleviation, management or prevention. There is no legal basis to equate these two frameworks as being identical.
Conducting simultaneous clinical trials for every indication is practically unfeasible due to variations in therapeutic guidelines and challenges in recruiting subjects for different indications. Companies are not obligated to apply for simultaneous product approvals. They may choose to submit applications either separately or together for the first approval based on the market conditions or sales strategies. Given these realities, it is unreasonable to assume that a patented use under patent laws will always align with the efficacy and effects required for a product approval under the pharmaceutical laws.
Determining the scope of a PTE based on the efficacy and effects defined under pharmaceutical laws would create an unreasonable disparity. Inclusion of multiple indications in a single product approval would result in a broader scope of extended patent rights compared to obtaining sequential, separate product approvals for each individual indication, even if both scenarios involve the same invention.

The First Approved Indication and the Compared Invention (Subsequently Approved Indication) Have the Same Therapeutic Effect and Use

The IP High Court held that a case-by-case determination must be made on whether the subsequently-approved indication has substantially the same therapeutic effect and medical use as the approved product that formed the basis for the extension, considering in the aggregate: the technical significance and core inventive concept of the patented invention; the medical uses described in the patent specification; the content of the product approval application; the pharmacological mechanism; the target organ or tissue; the targeted disease conditions; actual prescriptions and use; and the knowledge level of a person of ordinary skill in the art.

The IP High Court’s decision is significant in that it adopts a practical interpretation of the statute governing the scope of an extended patent, reflecting the realities of the pharmaceutical industry. It affirms a judicial bent towards protecting the rights of new drug developers who make heavy investments by curbing a generic strategy of excluding the first approved indication that formed the basis for a PTE and seeking approval only for subsequently-approved indications as an easy means to circumvent the extended patent right.

In this matter, our firm systematically defended and managed an unprecedented volume of proceedings – 213 trials before the Intellectual Property Trial and Appeal Board filed within a single month against the patent at issue and 47 suits filed with the IP High Court appealing those decisions – prevailing across the board. Of these, eight cases were further appealed to the Supreme Court, where two were summarily dismissed on May 15, 2025 without substantive review, and the other six remain pending. Of these, the K CAB decision is the IP High Court’s first ruling addressing the meaning of “specific use” under Article 95 of the Patent Act.

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