Federal Circuit Rejects Penumbra’s “Ministerial” Test for Provisional Prior-Art Dates

On August 10, 2026, the Federal Circuit issued a precedential decision in Dental Monitoring SAS v. Align Technology, Inc., fundamentally changing how the Patent Trial and Appeal Board determines whether a U.S. patent or published application qualifies for an earlier prior-art date under the America Invents Act (AIA). 

Background: Provisional Applications and Prior-Art Dates

Under the AIA, a U.S. patent or published application can serve as a prior art reference against another patent as of the date it was “effectively filed.” This “effective filing date” can reach back to an earlier provisional application only if the reference is “entitled to claim a right of priority to” or “the benefit of an earlier filing date of” that provisional under 35 U.S.C. § 119(e). Because a provisional application is an earlier, often lower-cost filing that does not require formal claims, it is a common mechanism for establishing early priority, up to 12 months before a non-provisional application is filed.

The practical significance is enormous: if the reference patent or publication can claim the benefit of its provisional filing date, its prior-art date extends back up to 12 months, which can be the difference between pre-dating and post-dating a challenged patent.

The Penumbra Rule: A “Ministerial” Standard

In RapidPulse, Inc. v. Penumbra, Inc., the PTAB held that a reference patent or publication is “entitled to claim” the benefit of an earlier application so long as (1) the applicant satisfied “ministerial requirements”—such as filing a timely benefit claim—and (2) the earlier application describes the specific subject matter from the reference relied upon as prior art. Critically, the Board’s precedential rule did not require the earlier application to provide written-description support under 35 U.S.C. § 112(a) for any claim of the reference.

On October 14, 2025, the Federal Circuit affirmed the Penumbra judgment by Rule 36 order. However, a Rule 36 affirmance establishes only that the judgment below was correct on the record presented; it does not endorse or reject any particular legal reasoning of the tribunal and carries no precedential value. Accordingly, the Rule 36 order did not validate the Board’s “ministerial” legal standard.

The Dental Monitoring Decision

In Dental Monitoring, the court squarely rejected the legal rule set forth in the Board’s precedential Penumbra decision. The court held that the phrase “entitled to claim a right of priority to” in § 102(d)(2) imports the substantive statutory entitlement requirements of § 119(e)(1), which in turn conditions priority on compliance with 35 U.S.C. § 112(a)’s written-description requirement. The court reasoned that “entitled to” cannot be reduced to merely asserting priority or meeting ministerial formalities.

The decision establishes a cumulative two-part framework for determining whether a reference patent may claim an earlier prior-art effective date:

• Part 1 (Claim Support): The earlier provisional application must provide written-description support under § 112(a) for at least one claim of the reference patent or published application. This is the element the Penumbra rule omitted.    
• Part 2 (Subject-Matter Description): The earlier provisional application must also describe the specific subject matter from the reference patent that is actually relied upon as prior art against the challenged patent. This requirement was already part of the Penumbra framework and remains in effect.

Both parts must be satisfied for the reference to receive the earlier effective filing date.

Because the Board had not determined whether the Carrier provisional provided § 112(a) written-description support for at least one claim, the Federal Circuit vacated and remanded for the PTAB to make that finding in the first instance. The court did not itself decide that Carrier was not prior art; it held that the Board had applied the wrong legal standard.

Implications for Foreign-Priority Prior Art

Because the Dental Monitoring decision involved a U.S. provisional application under § 119(e), the decision’s reasoning has significant implications for prior art relying on foreign-priority dates. Under the AIA, § 102(d)(2) now permits qualifying U.S. patent documents to receive prior-art effective dates based on earlier foreign applications filed under § 119(a). See MPEP § 2154.01.

Existing Federal Circuit precedent already requires that a foreign-priority application provide § 112 written-description support for the claims of the later U.S. application. See In re Gosteli, 872 F.2d 1008, 1010–12 (Fed. Cir. 1989). The Dental Monitoring court’s holding—that “entitled to claim a right of priority” requires substantive § 112(a) compliance, not merely ministerial steps—strongly suggests that the same claim-support requirement applies when a reference relies on a foreign-priority application under § 119(a) to establish its prior-art date. However, because Dental Monitoring decision involved only a U.S. provisional under § 119(e), whether the Federal Circuit would extend the same holding to § 119(a) foreign priority remains an unanswered question.

The Dental Monitoring decision confirms under the current law that when relying on an earlier priority date for prior art, the earlier priority filing should fully support the relied-upon subject matter in the reference and at least one claim of the reference.  

If you have any questions about the issues raised in this alert, please contact Kyle Kellar or the Womble Bond Dickinson attorney with whom you normally work.