definiens: means any an d all of the following : ( a ) a Development Candidate for a Lexicon Target that is so designated under Section 2.5 hereof ; an d ( b ) any Back - up Compound(s ) designated for such Development Candidate ; and ( c ) any other Small Molecule Compound that acts through the same Lexicon Target : ( i ) that is made in the course of performing med icinal chemistry on or optimizing such Development Candidate and Back - up Compound(s ), or performing st ructure activity relationship activities using such Development Candidate, Back - up Compound(s ) or other Program Compounds active against such Lexicon Targ et ; provided that such Small Molecule Compound is first synthes ized within four ( 4 ) years after the expiration or earlier termination, in accordance with Section 2.5 .3.1, of [COMPANY] ’s obligations with respect to Research Program Activities requested by Lexicon relating to such Le xicon Target ; or 5 ( ii ) that is Covered by a Valid Claim of any Pro gram Patent Rights ; and ( d ) any salts of any of the foregoing