In re Yamazaki: Terminal Disclaimers and Reissue Applications

A terminal disclaimer is a short document with long consequences. Filed to get past a double patenting rejection, it can permanently shorten a patent’s life and tie its enforceability to another patent. In re Yamazaki (Fed. Cir. 2012) shows that once the shortened term has run, reissue cannot be used to undo that choice.

This article explains what terminal disclaimers are, why they are filed and what the Yamazaki decision teaches about the limits of reissue.

What a terminal disclaimer is

Under 35 U.S.C. § 253(b), a patentee or applicant may disclaim or dedicate to the public the entire term, or any terminal part of the term, of a patent. A terminal disclaimer gives up the end portion of the term, so the patent expires earlier than it otherwise would.

The procedure is set out in 37 C.F.R. § 1.321. The disclaimer must be signed by the proper party, identify the patent or application, and be accompanied by the required fee. Once recorded, it becomes part of the patent and is printed or noted on it.

Why terminal disclaimers are filed

The most common reason is to overcome a rejection for obviousness-type (nonstatutory) double patenting. This judge-made doctrine prevents an applicant from extending the effective life of protection by obtaining a second patent on an obvious variation of an invention already claimed in an earlier patent or application.

A terminal disclaimer resolves the concern in two ways:

• Term. The later patent is disclaimed so it expires no later than the reference patent.
• Common ownership. Under § 1.321(c), the disclaimer must include a provision that the patent is enforceable only for and during the period it is commonly owned with the reference patent. This keeps two different owners from suing the same accused infringer on patentably indistinct inventions.

Different rules apply where the patents resulted from activities under a joint research agreement; those are addressed in § 1.321(d).

The Yamazaki decision

In Yamazaki, the patent was subject to a terminal disclaimer that tied its term to an earlier patent. By operation of the disclaimer, the patent’s term ended. In reissue, the patentee sought to withdraw the disclaimer and so recover the additional term the patent would otherwise have had.

The Federal Circuit rejected that effort. Section 251 permits reissue only “for the unexpired part of the term of the original patent.” Because the disclaimer had already taken effect and the patent’s term had ended, there was no unexpired term left to reissue. The court treated the disclaimed term as gone; the patentee could not use reissue to escape the disclaimer after the fact.

Why the decision matters

Yamazaki closes a door that some patentees hoped would stay open. Its lessons are practical:

• Disclaimers are difficult to undo. Once a disclaimed term has expired, reissue cannot restore it.
• Reissue depends on remaining term. A reissue application must be filed, and the patent reissued, while the original patent still has an unexpired term. See the reissue applications guide.
• The choice deserves analysis at the time. Filing a terminal disclaimer is often the quickest way past a double patenting rejection, but the alternatives, such as arguing that the claims are patentably distinct or amending them, may preserve term and independent enforceability.

Considerations before filing a terminal disclaimer

Owners and applicants commonly weigh:

Consideration	Why it matters
Lost term	The patent may expire years earlier than it otherwise would.
Common ownership	The patents cannot be split among owners without risking unenforceability.
Licensing and sale	Buyers and licensees must account for linked patents.
Strength of the rejection	A weak double patenting rejection may be worth contesting.
Later correction	As Yamazaki shows, reissue cannot rescue an expired disclaimed term.

For an overview of statutory and terminal disclaimers, see the disclaimers guide. For how reissue works more broadly, see reissue procedure, advantages and pitfalls, and for a reissue used to add claims, see In re Tanaka.

USPTO practice on terminal disclaimers has been the subject of rulemaking proposals over the years. Check the current MPEP and Federal Register notices for the requirements that apply today.

Key takeaways

• A terminal disclaimer under 35 U.S.C. § 253(b) and 37 C.F.R. § 1.321 gives up the end of a patent’s term.
• It is usually filed to overcome obviousness-type double patenting and must include a common-ownership enforceability provision.
• In re Yamazaki (Fed. Cir. 2012) held that reissue cannot undo a terminal disclaimer once the disclaimed term has expired.
• Reissue is available only for the unexpired part of the original term.
• Because the effects are lasting, the decision to file a terminal disclaimer deserves care.