Patent Term Extension in Korea for Pharmaceutical and Agrochemical Patents

Korean Patent Act Article 89 permits extension of an eligible patent when regulatory testing required for approval or registration prevented practice of the patented invention. The extension is limited to the qualifying period and cannot exceed five years.

For an approval or registration obtained on or after July 22, 2025, the extended term cannot continue beyond 14 years from that approval or registration date. Only one patent may be selected for one approval or registration.

Eligible pharmaceutical and agrochemical inventions

Article 7 of the Enforcement Decree limits the eligible categories. For pharmaceuticals, eligibility concerns the first marketing approval for a product manufactured with a new substance as the active ingredient, where the chemical structure of the active moiety is new. The rule also covers qualifying first approvals for narcotic or psychotropic drugs with a new active substance.

For agrochemicals, eligibility concerns the first registration of a pesticide or technical-grade active ingredient manufactured with a new substance as the active ingredient.

The patent claims must cover the invention practiced in connection with the relevant approved or registered product. Eligibility therefore requires comparison of the claims with the active ingredient, product, approved use, patent owner, approval holder and regulatory record.

Extension period

The extension corresponds to the period during which the patented invention could not be practised because the required approval or registration was pending. Article 89 excludes time attributable to the approval or registration holder. The resulting extension remains subject to the five-year maximum.

For approvals and registrations subject to the July 22, 2025 amendment, the extended term is also subject to the 14-year limit measured from the approval or registration date. The applicable statutory limits must be applied to the calculated period.

One patent for one approval

Article 90(7) requires the applicant to select one patent when more than one patent relates to the same approval or registration. If extension applications for two or more patents remain filed for the same approval or registration, none of those patents can be extended under that provision.

The selected patent should be assessed for:

• claim coverage of the approved product and use;
• the remaining ordinary patent term;
• the likely form of a generic or follow-on product;
• validity and relevant prior art;
• availability of infringement evidence;
• MFDS patent-listing or other regulatory status;
• related composition, formulation, dosage, process and use patents; and
• the effect of the 14-year post-approval limit.

The broadest claim is not necessarily the appropriate selection if it has material validity risk or does not correspond clearly to the approved product.

Application deadline and fee

Article 90 requires the extension application to be filed within three months after the approval or registration. An application cannot be filed during the final six months before expiration of the ordinary patent term. Review should therefore begin before approval where the patent is approaching expiration.

The official filing fee for a patent-term extension application is KRW 300,000. Professional fees and translation charges are separate.

Application records

The application and supporting review generally require:

• the Korean patent and the claims proposed for extension;
• the marketing approval or agrochemical registration;
• the approved product, active ingredient, formulation and use;
• the regulatory testing and approval chronology;
• periods attributable to the approval or registration holder;
• the relationship between the patent owner and approval holder, where relevant;
• the requested extension period and calculation; and
• confirmation that only the selected patent is being pursued for the approval or registration.

The claim analysis should use the final Korean claims and the complete regulatory record. Product names or a foreign patent-family summary are not substitutes for that comparison.

Effect of the extended patent

Article 95 limits the effect of a patent during the extended period to practice of the patented invention concerning the product that was the subject of the approval or registration. If the approval or registration specifies a use, the effect is limited to the product used for that approved purpose.

The extended term should therefore be considered together with the exact claim language and approval. Product, composition, use, dosage and manufacturing claims may present different coverage questions.

Regulatory and patent-listing matters

The extension analysis should be coordinated with the MFDS or agrochemical approval, applicable patent-listing position, generic entry, data protection and possible invalidity challenges. These matters do not replace the statutory extension analysis, but they affect the commercial consequences of selecting one patent.

Official references

• Patent Act Article 89
• Patent Act Article 90
• Patent Act Article 95
• Patent Act Enforcement Decree Article 7
• MOIP patent fee schedule

Related Korean patent guidance

• Divisional Patent Applications in Korea
• Patent Annuities in Korea: Due Dates, Grace Periods and Restoration
• Patent Invalidation and Cancellation Proceedings in Korea

Legal and editorial review: July 16, 2026. MOIP is Korea's current IP authority; some official English pages may retain KIPO or transitional terminology.

This article provides general information, not legal advice. Eligibility, the filing deadline and the extension calculation must be confirmed for the specific patent and approval.