guidance issued by the Secretary addressing formal meetings for sponsors of human drug applications, as defined in section 735. . (c) Product differentiation Section 586C of the Federal Food, Drug, and Cosmetic Act ( 21 U.S.C. 360fff–3 ) is amended by adding at the end the following: (f) Product differentiation (1) In general A final sunscreen order shall have the effect of providing the order requestor (or the licensees, assignees, or successors in interest of such requestor with respect to the subject of such request and listed under paragraph (5)) the exclusive right, for a period of 2 years, to market a sunscreen ingredient under this section incorporating changes described in paragraph (2) subject to the limitations under paragraph (4), beginning on the date the requestor (or any licensees, assignees, or successors in interest of such requestor with respect to the subject of such request and listed under paragraph (5)) may lawfully market such sunscreen ingredient pursuant to the order. (2) Changes described A change described in this paragraph is a change subject to an order specified in paragraph (1) that— (A) permits a sunscreen to contain an active ingredient not previously incorporated in a marketed sunscreen listed in paragraph (3)