; or (3) is a product that would benefit from early scientific engagement due to complexity or uncertainty concerning the approval pathway under section 505(j). . 312. Increasing pharmaceutical options to treat an unmet medical need Subsection (b) of section 506 of the Federal Food, Drug, and Cosmetic Act ( 21 U.S.C. 356 ) is amended by adding at the end the following: (4) Unmet medical need For purposes of paragraph (1), a drug shall be deemed to address an unmet medical need for a disease or condition if fewer than 3 available drugs exist for the treatment of such disease or condition. . 313. Preemption of State barriers to the substitution of biosimilar products No State, or any political subdivision thereof, may, under any circumstances, prohibit a pharmacy or pharmacist from dispensing, in place of a biological reference product, any biosimilar that the Food and Drug Administration has designated as an interchangeable product for that biological reference product. C Limiting Exclusivity Periods Delaying Competition 321. Limiting exclusivity periods for drugs treating rare diseases and conditions (a) In general Subsection (a) of section 527 of the Federal Food, Drug, and Cosmetic Act ( 21 U.S.C. 360cc ) is amended to read as follows: (a) Exclusivity (1) In general Except as provided in subsection (b), if the Secretary approves an application filed pursuant to section 505, or issues a license under section 351 of the Public Health Service Act, for a drug designated under section 526 for a rare disease or condition, the Secretary may not approve an application filed pursuant to section 505, or issue a license under section 351 of the Public Health Service Act, for the same drug for the same disease or condition for a person who is not the holder of such approved application or of such license until the expiration of the exclusivity period described in paragraph (2). (2) Exclusivity period described The exclusivity period described in this paragraph, with respect to a drug designated under section 526 for a rare