21 CFR §314.90

1. (a)An applicant may ask the Food and Drug Administration to waive under this section any requirement that applies to the applicant under §§ 314.50 through 314.81. An applicant may ask FDA to waive under § 314.126(c) any criteria of an adequate and well-controlled study described in § 314.126(b). A waiver request under this section is required to be submitted with supporting documentation in an NDA, or in an amendment or supplement to an NDA. The waiver request is required to contain one of the following:
   1. (1)An explanation why the applicant's compliance with the requirement is unnecessary or cannot be achieved;
   2. (2)A description of an alternative submission that satisfies the purpose of the requirement; or
   3. (3)Other information justifying a waiver.
2. (b)FDA may grant a waiver if it finds one of the following:
   1. (1)The applicant's compliance with the requirement is unnecessary for the agency to evaluate the NDA or compliance cannot be achieved;
   2. (2)The applicant's alternative submission satisfies the requirement; or
   3. (3)The applicant's submission otherwise justifies a waiver.
3. (c)If FDA grants the applicant's waiver request with respect to a requirement under §§ 314.50 through 314.81, the waived requirement will not constitute a basis for refusal to approve an NDA under § 314.125.