37 CFR § 2.67 - Suspension of action by the Patent and Trademark Office.
Action by the Office may be suspended for a reasonable time for good and sufficient cause. The fact that a proceeding is pending before the Office or a court that is relevant to the issue of initial or continued registrability of a mark and that proceeding has not been finally determined, or the fact that the basis for registration is, under the provisions of section 44(e) of the Act, registration of the mark in a foreign country and the foreign application is still pending, will be considered prima facie good and sufficient cause. An Office or court proceeding is not considered finally determined until an order or ruling that ends the proceeding or litigation has been rendered and noticed, and the time for any appeal or other further review has expired with no further review sought. An applicant's request for a suspension of action under this section, filed within the response period set forth in § 2.62(a), may be considered responsive to the previous Office action. The Office may require the applicant, registrant, or party to a proceeding to provide status updates and information relevant to the ground(s) for suspension, upon request.