; and (C) in paragraph (2), by striking such holder provides and inserting the holder provides ; and (3) by adding at the end the following: (c) Condition of clinical superiority (1) In general If a sponsor of a drug that is designated under section 526 and is otherwise the same, as determined by the Secretary, as an already approved or licensed drug is seeking exclusive approval or exclusive licensure described in subsection (a) for the same rare disease or condition as the already approved drug, the Secretary shall require such sponsor, as a condition of such exclusive approval or licensure, to demonstrate that such drug is clinically superior to any already approved or licensed drug that is the same drug. (2) Definition For purposes of paragraph (1), the term clinically superior with respect to a drug means that the drug provides a significant therapeutic advantage over and above an already approved or licensed drug in terms of greater efficacy, greater safety, or by providing a major contribution to patient care. (d) Regulations The Secretary may promulgate regulations for the implementation of subsection (c). Beginning on the date of enactment of the Orphan Products Extension Now Accelerating Cures and Treatments Act of 2017 , until such time as the Secretary promulgates regulations in accordance with this subsection, the Secretary may apply any definitions set forth in regulations that were promulgated prior to such date of enactment, to the extent such definitions are not inconsistent with the terms of this section, as amended by such Act. (e) Demonstration of clinical superiority standard To assist sponsors in demonstrating clinical superiority as described in subsection (c), the Secretary— (1) upon the designation of any drug under section 526, shall notify the sponsor of such drug in writing of the basis for the designation, including, as applicable, any plausible hypothesis offered by the sponsor and relied upon by the Secretary that the drug is clinically superior to a previously approved drug