37 CFR § 42.108 - Institution of review.

---
identifier: "/us/cfr/t37/s42.108"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "37 CFR § 42.108 - Institution of  review."
title_number: 37
title_name: "Patents, Trademarks, and Copyrights"
section_number: "42.108"
section_name: "Institution of  review."
chapter_name: "UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE"
subchapter_number: "A"
subchapter_name: "GENERAL"
part_number: "42"
part_name: "TRIAL PRACTICE BEFORE THE PATENT TRIAL AND APPEAL BOARD"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "35 U.S.C. 2(b)(2), 3, 6, 21, 23, 41, 134, 135, 143, 153, 311, 312, 314, 316, 318, 321-326, 328; Pub. L. 112-29, 125 Stat. 284; and Pub. L. 112-274, 126 Stat. 2456."
regulatory_source: "77 FR 48669, Aug. 14, 2012, unless otherwise noted."
cfr_part: "42"
---


# 42.108 Institution of  review.

(a) When instituting *inter partes* review, the Board will authorize the review to proceed on all of the challenged claims and on all grounds of unpatentability asserted for each claim.

(b) At any time prior to a decision on institution of *inter partes* review, the Board may deny all grounds for unpatentability for all of the challenged claims. Denial of all grounds is a Board decision not to institute *inter partes* review.

(c) *Inter partes* review shall not be instituted unless the Board decides that the information presented in the petition demonstrates that there is a reasonable likelihood that at least one of the claims challenged in the petition is unpatentable. The Board's decision will take into account a patent owner preliminary response where such a response is filed, including any testimonial evidence. A petitioner may seek leave to file a reply to the preliminary response in accordance with §§ 42.23 and 42.24(c). Any such request must make a showing of good cause.

[85 FR 79129, Dec. 9, 2020]