; or (B) the evidence required under section 351(a) of the Public Health Service Act for approval of a biologics license application for the drug shall include adequate and well-controlled investigations of the disparity; and (2) if the investigations confirm that there is a disparity, the labeling of the drug shall include appropriate information about the disparity. (b) Postmarket studies (1) In general If there is evidence that there may be a disparity on the basis of racial or ethnic background as to the safety or effectiveness of a drug for which there is an approved application under section 505 or a license under section 351 of the Public Health Service Act , the Secretary may by order require the holder of the approved application or license to conduct, by a date specified by the Secretary, postmarketing studies to investigate the disparity. (2) Labeling If the Secretary determines that the postmarket studies confirm that there is a disparity described in paragraph (1), the labeling of the drug shall include appropriate information about the disparity. (3) Study design The Secretary may specify all aspects of study design, including the number of studies and study participants, and the other demographic characteristics of study participants included, in the order requiring postmarket studies of the drug. (4) Modifications of study design The Secretary may by order modify any aspect of the study design as necessary after issuing an order under paragraph (1). (5) Study results The results from studies required under paragraph (1) shall be submitted to the Secretary as supplements to the drug application or biological license application. (c) Disparity The term evidence that there may be a disparity on the basis of racial or ethnic background for adult and pediatric populations as to the safety or effectiveness of a drug includes— (1) evidence that there is a disparity on the basis of racial or ethnic background as to safety or effectiveness of a drug in the same chemical class as the drug