This guidance describes circumstances in which an applicant may be eligible for a barrier-to-innovation waiver under the Prescription Drug User Fee Act (PDUFA)2 for some new drug applications (NDA) for fixed-combination (FC)3 and single-entity versions of previously approved antiretroviral therapies for the treatment of human immunodeficiency virus (HIV).4 FDA expects that most of the applications and post-approval fees for fixed-combination and HIV therapies proposed for use in the President's Emergency Plan for AIDS Relief (PEPFAR) will qualify for a waiver under the barrier-to-innovation user fee waiver.