USPTO narrows the reexamination path after an IPR final decision

A USPTO decision disclosed on 3 May tightens the link between inter partes review and ex parte reexamination. The key point is the timing of estoppel under 35 U.S.C. § 315(e)(1): a request for reexamination is not treated merely as a filing made on a particular day, but as a pending request that continues until the Office orders reexamination under 35 U.S.C. § 304.

That reading narrows a familiar strategy: challenge the patent first through IPR, then use ex parte reexamination as a second route if the IPR record begins to look unfavourable. If the IPR final written decision has already issued and the Office has not yet ordered reexamination, the requester may be barred from pursuing reexamination on the same grounds, or grounds that reasonably could have been raised in the IPR. Timing now affects not only efficiency, but whether the procedural path remains open at all.

The trigger moves beyond the filing date

The practical question was simple: if a party files an ex parte reexamination request before the IPR final written decision, has it avoided § 315(e)(1) estoppel? The USPTO’s answer is more restrictive. A request is not complete, for estoppel purposes, just because the paperwork has been submitted. Until the Office decides whether to order reexamination, the requester is still asking the Office to act.

This distinction matters because ex parte reexamination changes character once it is ordered. After that point, the proceeding is largely between the patent owner and the Office, with only limited control left to the third-party requester. Before the order, however, the Office is still considering whether the request should enter the reexamination system. The decision places estoppel pressure on that pre-order phase and makes last-minute reexamination filings far less reliable.

The backup route after IPR is less dependable

Many accused infringers have treated ex parte reexamination as a supplementary path alongside IPR. They may wait to see how the PTAB record develops, watch the oral hearing, assess panel questions, and then decide whether to file a reexamination request before the final written decision arrives. That approach now carries a sharper procedural risk.

Filing is not the same as institution of the reexamination. The Office still must decide whether the request raises a substantial new question of patentability. If the IPR final written decision issues during that review period, a requester may no longer be able to rely on the pending reexamination request as a safe parallel attack. The risk is not merely delay. The request itself may become vulnerable to estoppel.

The decision gives patent owners a cleaner procedural objection

For patent challengers, the lesson is to front-load the work. Prior art searching, claim mapping, and ground selection should be completed early if the strategy depends on both IPR and reexamination. Reusing the same art combinations, or combinations that could reasonably have been raised in the IPR, is now more likely to draw estoppel scrutiny if the reexamination order has not issued before the IPR decision.

Patent owners, by contrast, gain a more concrete objection point. When a reexamination request follows an IPR, counsel should check the sequence carefully: when the final written decision issued, when the reexamination request was filed, whether the § 304 order had already been entered, and how closely the asserted grounds overlap with the IPR record. These are not clerical details. They may determine whether the reexamination can proceed.

Invalidity planning needs a tighter timeline

The better response is not simply to file reexamination requests earlier. Parties should first ask whether both proceedings are necessary. IPR offers an adversarial forum and a defined schedule, but it brings estoppel. Ex parte reexamination has a different threshold and less third-party control after it begins. Treating reexamination as a rescue option after a weak IPR showing is now harder to justify.

Companies managing US patent disputes should build the estoppel timeline into their invalidity plan from the start. Search reports, IPR petitions, reexamination requests, and district court invalidity contentions should not be drafted in isolation. Grounds need to be separated deliberately: what belongs in IPR, what should not be repeated in reexamination, and what may be better preserved for litigation. Once the IPR decision is close, the room for tactical adjustment may already be gone.