21 CFR §60.26

1. (a)FDA will consider a regulatory review period determination to be final upon expiration of the 180-day period for filing a due diligence petition under § 60.30 unless FDA receives:
   1. (1)New information from PTO records, FDA records, or FDA centers that affects the regulatory review period determination;
   2. (2)A request under § 60.24 for revision of the regulatory review period determination;
   3. (3)A due diligence petition filed under § 60.30; or
   4. (4)A request for a hearing filed under § 60.40.
2. (b)FDA will notify PTO that the regulatory review period determination is final upon:
   1. (1)The expiration of the 180-day period for filing a due diligence petition; or
   2. (2)If FDA has received a request for a revision, a due diligence petition, or a request for a hearing, upon resolution of the request for a revision, the petition, or the hearing, whichever is later. FDA will send a copy of the notification to the applicant and file a copy of the notification in the docket established for the application in FDA's Dockets Management Staff (HFA-305), 5630 Fishers Lane, rm. 1061, Rockville, MD 20852.