A recent Federal Circuit decision serves as a reminder to exercise caution when dealing with large patent families with many priority claims.

Background: Natural Alternatives v. Iancu^[1] involved an appeal from an inter partes reexamination. At issue in Natural Alternatives was whether a later-filed child application was entitled to priority to the earliest effective filing date when there was a modification to the priority claim by an Applicant in a previous related application.  The patent at issue, U.S. Patent No. 8,067,381 (“the ‘381 patent”), was the last application in a family of U.S. applications claiming priority to the original filing date of the parent, which was filed August 12, 1997.

As shown in this diagram, the chain began when Natural Alternatives International (“NAI”) filed the parent application^[2] related to a dietary supplement for increasing an athlete’s endurance. Between 1997 and 2011, NAI filed at least seven more applications with similar subject matter, each of them including a benefit priority statement (at least initially) claiming priority through the chain to the 1997 parent. The patent at issue, the ‘381 patent, issued from the eighth application in the chain

The fifth application in the chain^[3], which included new matter, initially claimed priority to the filing date of the first application (via the fourth application) as a continuation-in-part (“CIP”). The fifth application separately claimed the benefit a 2003 provisional application. During the pendency of the subsequent sixth application, the fifth application was amended to remove the priority claim to the first four applications, while maintaining the priority claim to the provisional application, presumably to extend the patent term of the fifth application. The priority claim of the sixth application was not amended. In addition, all of the subsequent applications included priority claims extending all the way back to the 1997 filing date of the first application.

uring the reexamination proceedings, NAI argued that the ‘381 patent should have a 1997 effective filing date. The reexamination examiner was not persuaded, and the claims of the ‘381 patent were finally rejected based on prior art (which included the patent issuing from NAI’s original 1997 filing). In the subsequent proceeding, the Patent Trial and Appeal Board issued a determination affirming the examiner’s rejections. NAI filed an appeal with the Federal Circuit.

 NAI’s argument before the Federal Circuit included four parts:

1. The sixth application’s priority “vested” (thus providing a path to 1997 for the eighth patent).

2. Waiver of priority is limited to the instant application and does not extend to subsequent applications in the chain.

3. The priority chain is not a single growing chain, but rather a set of multiple fixed chains (i.e., one for each application).

4. Viewing a priority chain as a single growing chain “limits an applicant’s ability to seek protection” when “amending [a] priority claim to gain [patent] term.”

The Federal Circuit found that the “vesting argument” confused claiming priority with entitlement to priority. The court recognized that the burden is on an applicant or patentee to prove priority, and that entitlement to priority is not assumed even where a proper priority claim exists.  The court then cited prior Federal Circuit decisions (and consistent MPEP language) recognizing that the modification of a priority claim can affect downstream applications in a priority chain. “[B]ecause the fifth application lacked priority to the first application, the eighth application's priority claim to the first application (via the fifth application) did not satisfy all of § 120's requirements.”^[4]

Next, the court rejected NAI’s argument that a cancellation of a priority claim waives priority only in the instant application. The argument was based on NAI’s reading of MPEP § 201.11^[5], which NAI found that an alteration of a priority claim applies “only to the instant application – not other, ... applications.”^[6] The court, while acknowledging that the MPEP “does not have the force of the law,” found nothing in the MPEP that limits waiver of priority to only the instant application and noted the MPEP has explicitly indicated when certain actions affect downstream applications (for example, terminal disclaimers).^[7]

The Federal Circuit summarily rejected the final two arguments on grounds similar to those discussed above.

The opinion also serves as a reminder to practitioners about the effective filing date for CIP applications: while the effective filing date for claims in a CIP application are based on the earliest filing of the claimed subject matter (determined claim-by-claim), the patent term for the entire application (all claims) is based on the earliest claimed priority.^[8] In other words, all claims in a CIP application expire at the same time even though certain claims may have different priority dates. As a result, claims reciting new matter have a truncated patent term. While it is permissible to disclaim the benefit of an earlier date to secure a full 20-year term, such a disclaimer opens up the application to a larger pool of prior art.

Takeaways:

1. Applicants should be wary of modifying priority claims in related applications. In the rare circumstance where it makes strategic sense to cancel a priority claim (with knowledge that the upstream applications could end up as prior art), an applicant should be aware that such a disclaimer may break the priority chain not just for the instant application but also for later-filed applications in the chain.

Further, claims to priority should be carefully monitored through related applications, whether in an Application Data Sheet, the first paragraph of the specification, or both. A broken priority chain not only affects the priority of the instant application, but can be fatal to downstream child applications.

2. When filing a CIP application, it may be advisable to also file a co-pending continuation stemming from the immediate parent. Then, if the applicant wishes to disclaim priority in the CIP at a later date (i.e., to extend the patent term of new matter), the co-pending continuation will provide the application with an application with an unbroken chain of priority.

_{[1] Natural Alternatives v. Iancu, __ F.3d __, No 2017-1962 slip Op. (Fed. Cir. Oct. 1, 2018).}

_{[2] The 1997 patent application (Ser. No. 08/909,513) claims priority to two UK filings (9621914.2 and 9616910.7)}

_{[3] U.S. Application No. 12/231,240, filed on August 29, 2008.}

_{[4] Natural Alternatives, slip Op. at 10.}

_{[5] The relevant subject matter now exists in MPEP § 11.}

_{[6] Natural Alternatives, slip Op. at 10.}

_{[7] Id. at 10-11.}

_{[8] Id. at 11 (citing 35 U.S.C. § 154(a)(2)).}