RCEs and Patent Term: The B-Delay Trade-Off Every Applicant Should Understand

A request for continued examination (RCE) under 35 U.S.C. § 132(b) is one of the most commonly used prosecution tools — and one of the most consequential for patent term. Filing an RCE excludes the entire period of continued examination from B-Delay, the PTA category that compensates applicants when the USPTO takes more than three years to issue a patent. For applications with lengthy prosecution histories, this exclusion can cost hundreds of days of patent term. Yet RCEs remain attractive because they reopen prosecution and allow further engagement with the examiner. Understanding the term trade-off is essential for making an informed choice between filing an RCE and pursuing other options like appeal.

Scope: This article covers the impact of RCEs on PTA under 35 U.S.C. § 154(b)(1)(B) and related case law. For PTA fundamentals, see our PTA vs PTE comparison. For applicant delay rules that interact with RCE filings, see our applicant delay guide.

How B-Delay Works

B-Delay under 35 U.S.C. § 154(b)(1)(B) guarantees that a patent will issue within three years of the actual filing date. For each day beyond the three-year mark that the patent remains unissued, one day of PTA accrues as B-Delay. The three-year clock starts on the actual filing date of the application (or the date of national stage commencement for PCT applications).

However, certain periods are excluded from the three-year calculation — meaning the clock is tolled and B-Delay does not accrue during these exclusions. The most significant exclusion is for continued examination:

35 U.S.C. § 154(b)(1)(B)(i) provides that B-Delay does not include "any time consumed by continued examination of the application requested by the applicant under section 132(b)."

What "Time Consumed by Continued Examination" Means

The scope of the RCE exclusion was clarified by two Federal Circuit decisions:

In Novartis AG v. Lee, 740 F.3d 593 (Fed. Cir. 2014), the court held that "time consumed by continued examination" ends when a notice of allowance is mailed. Before Novartis, the USPTO had taken the position that the exclusion extended all the way through issuance, effectively denying B-Delay for any post-RCE prosecution. The court rejected this, holding that examination "presumptively ends at allowance, when prosecution is closed."

Following Novartis, the USPTO revised 37 CFR 1.703(b)(1) to define the RCE exclusion as the period from the date the RCE is filed until the mailing of a notice of allowance. See the 2015 Final Rule.

In Mayo Foundation v. Iancu, 2018-2031 (Fed. Cir. 2019), the court addressed whether an interference declaration effectively ends continued examination (analogous to allowance). The court held that it does not: after an interference concludes, jurisdiction returns to the examiner, and further examination is routine rather than exceptional. The entire period from the RCE filing through the post-interference examination remained excluded from B-Delay.

The Cost of an RCE in Patent Term

The practical impact depends on where the application stands relative to the three-year mark.

If prosecution is within 3 years of filing: B-Delay has not yet begun accruing. An RCE filed during this period may have little term impact because the three-year clock is simply tolled during continued examination.

If prosecution has passed 3 years: B-Delay is actively accruing. Filing an RCE at this point stops B-Delay accrual for the entire duration of continued examination. Every day spent in post-RCE prosecution — waiting for the examiner, responding to new rejections, even time consumed by the USPTO itself — is excluded from B-Delay.

This is where the cost becomes dramatic. If an RCE is filed 3.5 years into prosecution and the application is not allowed until year 5.5, the RCE exclusion covers 2 years (730 days) that would otherwise have accrued as B-Delay. That is 2 years of patent term lost.

RCE vs Appeal: The Strategic Trade-Off

The alternative to an RCE after a final rejection is typically an appeal to the Patent Trial and Appeal Board (PTAB) under 35 U.S.C. § 134. Appeal does not trigger the B-Delay exclusion — time spent in appellate review continues to count toward the three-year period, allowing B-Delay to accrue.

However, appeal carries its own considerations:

Timeline. PTAB appeals currently take approximately 12–24 months from filing the appeal brief to a Board decision, though this varies. During this time, B-Delay accrues (assuming the application is past the 3-year mark).

C-Delay potential. If the appeal results in a reversal of an adverse determination of patentability, the applicant may be entitled to C-Delay under 35 U.S.C. § 154(b)(1)(C)(iii) — additional PTA for the pendency of the appellate review. However, the requirements for C-Delay are strict. In SawStop Holding LLC v. Vidal, 2021-1537 (Fed. Cir. 2022), the Federal Circuit held that C-Delay requires both (1) a reversal of an adverse determination of patentability and (2) that the patent issue under the decision in the review. If the Board overturns one rejection but issues a new one, or if the claims are substantively amended after the appeal, C-Delay may not be available.

In Chudik v. Hirshfeld, 2020-1833 (Fed. Cir. 2021), the court underscored the RCE cost: the applicant filed an RCE before appealing, triggering the B-Delay exclusion for nearly two years. The court noted that the B-Delay exclusion for 655 days "illustrates what applicants should understand when deciding whether to request a continued examination rather than take an immediate appeal."

Risk. Appeal locks in the current claim set (unless new grounds of rejection are issued). If the Board affirms the rejection, the applicant may still need to file an RCE or amend claims, adding further delay.

Interaction with Applicant Delay

RCE filings also interact with applicant delay under 37 CFR 1.704(c):

IDS after RCE. Filing an IDS after an RCE is treated as a supplemental reply under § 1.704(c)(8), generating applicant delay measured from the RCE filing date to the IDS filing date. This reduction can be avoided with a safe harbor statement.

Multiple RCEs. Each RCE triggers a new exclusion period. Multiple RCEs in a single prosecution compound the B-Delay loss and can also trigger additional applicant delay if IDS filings or supplemental papers follow each RCE.

RCE after appeal. Filing an RCE in response to a PTAB decision (for example, to address a new ground of rejection) triggers the B-Delay exclusion from that point forward. If the applicant had been accruing B-Delay during the appeal, the RCE stops that accrual.

Worked Example: RCE vs Appeal Impact on Patent Term

When an RCE Still Makes Sense

Despite the B-Delay cost, RCEs remain the right tool in many situations:

• Early in prosecution (within 3 years). If B-Delay has not begun accruing, the RCE exclusion has minimal impact.
• When the examiner is close to allowing. If a brief continuation of examination will likely result in allowance, the RCE cost may be modest compared to the time and expense of an appeal.
• When claims need significant rework. Appeal locks in the current claims. If the applicant needs to substantially amend or add claims, an RCE is the practical path.
• When the appeal risk is high. If the rejection is well-founded and likely to be affirmed, filing an RCE to try a different approach may be preferable to spending 12–24 months on an appeal that fails.

The key is to make the decision with full awareness of the term trade-off rather than defaulting to an RCE out of habit.

Last reviewed: April 2026

Authorship: Written by the patentreply.ai editorial team. See our editorial methodology for how guides are drafted, sourced, and reviewed.

Legal disclaimer: This article is for informational purposes only and does not constitute legal advice. Consult a registered patent attorney or agent for advice specific to your situation. patentreply.ai is not a law firm.