1. Study on the substitution of interchangeable biological products (a) Report on biosimilar biological product interchangeability Not later than 4 years after the date of enactment of this Act, the Secretary of Health and Human Services (referred to in this section as the Secretary ), acting through the Commissioner of Food and Drugs, shall submit to the Committee on Health, Education, Labor, and Pensions of the Senate and the Committee on Energy and Commerce of the House of Representatives a report on the designation of biosimilar biological products as interchangeable, under section 351(k)(4) of the Public Health Service Act ( 42 U.S.C. 262(k)(4) ). Such report shall— (1) describe any challenges faced by manufacturers in developing and obtaining approval under section 351(k) of such Act for biosimilar biological products that receive such interchangeability designation; (2) summarize the experience of the Food and Drug Administration in reviewing applications for biosimilar biological products that seek an interchangeability designation, including compared to applications for biosimilar biological products under such section 351(k) that do not seek such designation; (3) summarize, at a high level, the data and information that the Food and Drug Administration has reviewed to support applications for interchangeability under section 351(k)(4) of such Act, including data from switching studies, and the differences between the findings from such data and information compared to the data and information that the Food and Drug Administration has reviewed for biosimilar biological products that have not received a designation of interchangeability; (4) describe the existing authority of the Food and Drug Administration to determine, on a case-by-case basis, the evidence needed to support an interchangeability designation, and how the Food and Drug Administration has used such authority, including the factors that the agency may consider when making those judgements