How Long Does a Japanese Patent Last, and Can the Term Be Extended?

Japanese Attorney at Law - Bengoshi L.L.

• 8 min read

Understanding the duration of patent protection is fundamental for any business relying on intellectual property. In Japan, while there is a standard term for patent rights, specific provisions allow for extensions, particularly for inventions in regulated sectors like pharmaceuticals and agricultural chemicals where pre-market approvals can significantly delay commercialization. This article explores the standard patent term in Japan and delves into the crucial system for Patent Term Extension (PTE).

I. The Standard Patent Term in Japan (Article 67(1) of the Patent Act)

A. Duration: 20 Years from the Filing Date

The term of a patent right in Japan expires after a period of 20 years calculated from the filing date of the patent application (Article 67(1)).

  • This means the "clock" starts ticking from the day the application is officially filed with the Japan Patent Office (JPO).
  • Crucially, the term is not calculated from the date the patent is granted, nor from any claimed priority date (though a priority date is vital for assessing novelty and inventive step).

B. Rationale for a Fixed Term from Filing

This approach of calculating the term from the filing date, rather than the grant date, serves several purposes:

  • Certainty for the Public: It provides a clear and predictable date upon which the patented invention will enter the public domain and become freely available for use by anyone.
  • Independence from Examination Delays: The expiration date is not affected by how long the JPO takes to examine the application and grant the patent. This prevents an indefinite extension of the monopoly period due to administrative backlogs.
  • International Harmonization: This aligns with international standards, notably Article 33 of the TRIPS Agreement, which mandates a minimum patent term of 20 years from the filing date.

C. Calculation Nuances

Precisely, according to Japanese law principles for calculating periods, the 20-year term typically commences on the day following the filing date and expires on the 20th anniversary of the filing date itself.

II. Patent Term Extension (PTE) for Regulated Products (Article 67(2) et seq.)

While the 20-year term from filing is the general rule, Japanese patent law recognizes that for certain inventions, particularly pharmaceuticals and agricultural chemicals, a significant portion of this term can be consumed by mandatory regulatory review processes required before the product can be marketed. Without a mechanism to compensate for this lost time, the effective period of market exclusivity for such inventions would be substantially reduced, potentially undermining the incentive to invest in these R&D-intensive fields.

To address this, Japan has a system for Patent Term Extension (PTE).

A. The Rationale for PTE

The core purpose of the PTE system is to restore, to a certain extent, the patent term that was effectively lost while the patentee was unable to work the patented invention due to the time taken to obtain necessary statutory regulatory approvals related to safety and efficacy. These approvals are typically required under laws such as the Pharmaceutical and Medical Device Act (PMD Act, formerly the Pharmaceutical Affairs Law) for drugs and medical devices, or the Agricultural Chemicals Regulation Law for pesticides. The process of conducting clinical trials or other safety tests and obtaining these approvals can often take many years.

B. Eligibility for Patent Term Extension

For a patent to be eligible for a term extension, several conditions must be met:

  1. Type of Patented Invention: The patent must typically cover:
    • A new pharmaceutical product (active ingredient or formulation).
    • A new agricultural chemical product (active ingredient or formulation).
    • A new medical device requiring specific approval.
    • A process for manufacturing such products.
  2. Necessity of Regulatory Approval: There must have been a period during which the patented invention could not be worked because it was necessary to obtain a specific regulatory approval (disposition) as defined by a Cabinet Order. These are typically marketing approvals issued by the relevant authorities (e.g., Ministry of Health, Labour and Welfare (MHLW) for pharmaceuticals).
  3. The "Unworkable Period": The extension is granted for the period during which the invention could not be worked due to the time spent obtaining this specific regulatory approval. The maximum extension that can be granted is five years (Article 67(2)).

C. Calculating the Extendable Period ("Unworkable Period")

The actual period for which an extension can be sought (the "period during which the patented invention could not be worked") is carefully defined. It is calculated as the duration from the later of either:
* (a) The date on which testing (e.g., clinical trials for drugs) necessary to obtain the regulatory approval commenced; or
* (b) The date of patent registration (grant).
To:
* The day before the date the regulatory approval was officially received by the applicant/patentee (i.e., the date the disposition took effect).

This definition was clarified by the Supreme Court in the New Polypeptides Case (October 22, 1999). The logic is that the patentee could not work the invention before both having a granted patent and having started the necessary trials, and the unworkable period ends once the approval is received, allowing commercialization.

D. The Application Process for PTE (Article 67-2)

A patentee wishing to extend their patent term must file an application for PTE with the JPO.

  • Applicant: Only the patentee can apply. If the patent is co-owned, all co-owners must apply jointly.
  • Timing:
    • Generally, the PTE application must be filed within three months from the date the relevant regulatory approval was obtained (Article 4 of the Cabinet Order for Enforcement of the Patent Act).
    • However, the PTE application cannot be filed later than six months before the original 20-year patent term is due to expire.
    • There are also provisions if the approval is obtained very close to the patent's expiry.
  • Content: The application must specify the patent number, details of the regulatory approval (the "disposition"), the period of extension sought (up to 5 years and not exceeding the unworkable period), and the reasons justifying the extension.

E. Examination of the PTE Application by the JPO (Article 67-3)

The JPO examines the PTE application to determine if all statutory requirements are met. If grounds for rejection are found, the JPO will issue a notice, and the applicant has an opportunity to respond. If no grounds for rejection are found, or if they are overcome, the JPO will issue a decision to grant the extension.

Key Grounds for Rejection of a PTE Application (Article 67-3(1)):

  1. The regulatory approval was not "necessary" for working the patented invention (Art. 67-3(1)(i)): This is arguably the most contentious and litigated aspect of PTE. It questions whether the specific approval cited was truly the one that first enabled the working of the patented invention.
    • Initial JPO Practice and the "First Approval" Issue: For a long time, the JPO often took a strict stance, particularly for pharmaceutical patents. If a patent broadly covered a new active ingredient and its use for a particular indication, the JPO tended to consider only the very first regulatory approval for any product containing that active ingredient for that indication as the basis for PTE. Subsequent approvals for, say, different formulations, dosages, or slightly different patient populations for the same core drug/indication were often denied PTE on the grounds that the "patented invention" (the active ingredient for the core indication) could already be worked under the first approval.
    • Pashif Capsule Case (Supreme Court, April 28, 2011): This landmark decision brought significant nuance. The Supreme Court held that even if there was a prior approval for a drug with the same active ingredient and indication (Product A), if a later approval was obtained for a different product (Product B – e.g., a new formulation with different properties), and crucially, if Product A did not fall within the technical scope of any claim of the patent for which PTE was being sought, then PTE could be granted based on Product B's later approval. This was because the patented invention itself could not have been worked under the approval for Product A if Product A didn't embody the patented invention.
    • Bevacizumab Case (IP High Court, Grand Panel, May 30, 2014): This case further refined the understanding. The IP High Court held that even if a first-approved product (Product A) did fall within the patent's scope, if a subsequent regulatory approval for another product (Product B, using the same active ingredient) was for a genuinely "new use" (e.g., a new dosage regimen, a different administration route for the same core indication, or a distinct therapeutic indication) that was not permitted or covered by the first approval, then PTE could be granted based on this subsequent approval for that "new use." The court emphasized that the "working of the patented invention" that was prevented by the regulatory process is tied to the specific scope of what the particular regulatory approval permits. It recognized that a single patent might cover multiple distinct "workings" that require separate regulatory approvals to be legally marketed.
  2. The patentee, or their licensee, did not have the right to obtain the regulatory approval. (Art. 67-3(1)(ii))
  3. The requested extension period exceeds the actual period during which the invention could not be worked (as calculated by the statutory formula), or exceeds the five-year maximum. (Art. 67-3(1)(iii))
  4. The applicant for PTE is not the registered patentee. (Art. 67-3(1)(iv))
  5. If the patent is co-owned, the PTE application was not filed by all co-owners. (Art. 67-3(1)(v))

F. Effect and Scope of the Extended Patent Right (Article 68-2)

If a PTE is granted, the term of the patent right is extended beyond the original 20 years from filing by the approved extension period. However, this extended right is not as broad as the original patent right.

Crucial Limitation on Scope: The exclusive rights under the patent during the extended period are strictly limited to the working of the patented invention only with respect to:

  • (a) The specific "product" (e.g., the drug substance, the specific formulation) that was the subject of the particular regulatory approval which formed the basis for the extension.
  • (b) The specific "use" (e.g., the approved therapeutic indication, dosage, and administration route) of that product as defined in that regulatory approval.

This means that the extended patent right does not cover other products or other uses that might have been encompassed by the original, broader patent claims but were not the subject of the specific regulatory approval that led to the extension. For example, if a patent claims a chemical compound and its use as a pharmaceutical, and PTE is granted based on approval for "Use X" of that compound, the extended right will cover the compound for Use X, but not for a completely different, unapproved "Use Y" that might also have been covered by the original patent claims.

The Bevacizumab case (IP High Court, Grand Panel, May 30, 2014) also provided influential commentary on this, suggesting that for pharmaceutical patents, the scope of the extended right is typically defined by the approved active ingredient, its approved efficacy/effect (indication), and its approved dosage and administration regimen. This "pinpoint" extension ensures that the compensation is tailored to the specific marketed product and use whose commercialization was delayed.

III. Maintaining Your Patent: Annuities

It's important to remember that to keep a patent in force for its standard 20-year term, and for any extended term granted, annual maintenance fees (annuities) must be paid to the JPO. These fees typically increase as the patent ages. Failure to pay the required annuities by the due dates (or within a grace period, usually with a surcharge) will result in the patent lapsing and the rights being extinguished prematurely.

Conclusion

The standard term of a patent in Japan is 20 years from the application filing date, providing a significant period of exclusivity. For innovators in fields like pharmaceuticals and agricultural chemicals, where lengthy pre-market regulatory reviews are mandatory, the Patent Term Extension system offers a vital mechanism to partially recover patent term lost due to these approval processes.

However, obtaining a PTE is not automatic. It requires a timely and compliant application, a clear demonstration that the regulatory approval was indeed necessary for working the patented invention, and accurate calculation of the unworkable period. Furthermore, the scope of the patent right during any extended term is carefully circumscribed to the specific product and use that formed the basis of the regulatory approval. A thorough understanding of these complex provisions, informed by evolving case law, is essential for businesses in relevant sectors to maximize the value and effective life of their Japanese patent assets.