35 U.S.C. § 325 — Relation to other proceedings or actions

(a) Infringer's Civil Action. (1) Post-grant review barred by civil action. A post-grant review cannot start if, before the petition was filed, the petitioner, or someone with the same interest, already filed a civil lawsuit challenging the patent claim's validity. (2) Stay of civil action. If the petitioner files that kind of lawsuit on or after filing the review petition, the lawsuit automatically pauses until: (A) the patent owner asks the court to lift the pause; (B) the patent owner sues or countersues for infringement; or (C) the petitioner asks the court to dismiss the lawsuit. (3) Treatment of counterclaim. A counterclaim challenging validity does not count as a "civil action" for this subsection. (b) Preliminary Injunctions. If someone sues for infringement within three months after a patent is granted, the court cannot pause its review of the patent owner's request for a preliminary injunction, just because a post-grant review petition was filed or a review was started. (c) Joinder. If more than one petition for post-grant review is properly filed against the same patent, and the Director decides more than one deserves review, the Director can combine them into a single review. (d) Multiple Proceedings. Despite sections 135(a), 251, 252, and chapter 30, if another Patent Office matter involving the same patent is pending during a post-grant review, the Director can decide how the review and the other matter proceed, including pausing, transferring, combining, or ending either one. When deciding whether to start a proceeding under this chapter or chapters 30 or 31, the Director can reject a petition or request because the same or similar prior art or arguments were already presented to the Office. (e) Estoppel. (1) Proceedings before the office. If a post-grant review of a patent claim ends in a final written decision under section 328(a), the petitioner, or the same-interest party, cannot later ask the Office to reconsider that claim on any ground it raised or reasonably could have raised during that review. (2) Civil actions and other proceedings. The same petitioner also cannot argue, in a federal court lawsuit under 28 U.S.C. § 1338 or in an International Trade Commission proceeding under section 337 of the Tariff Act of 1930, that the claim is invalid on any ground it raised or reasonably could have raised during that review. (f) Reissue Patents. A post-grant review cannot start if the petition asks to cancel a reissue patent claim that is identical to, or narrower than, a claim in the original patent, and the time limit in section 321(c) would have blocked a petition against that original patent.