definiens: means ( i ) irofulven or 6 - hydroxymethylacylfulvene ( also known as HMAF or MGI-114 or IUPAC name, ( 6‘R)-6’-hydroxy-3’-(hydroxymethyl)- 2’,4’,6’- trimethylspiro[cyclopropane-1,5’-inden]-7’(6‘H)-one or ( 5‘R)-5’-hydroxy-1’- ( hydroxy methyl)-2’,5’,7’-trimethylspiro[cyclopropane-1,6’-indene]-4’-one ) ( CAS No . 158440 - 71 - 2 and/or CAS 187 277 - 46 - 9 ) ( FDA UNII 6B799IH05A http://fdasis.nlm.nih.gov/srs/ProxyServlet?mergeDat a = true&objectHandle = DBMaint&A PPLICATION NAME = fdasrs&actionHandle = default&nextPage = jsp / srs / R esultScreen.js p&TXTSUPERLISTID=6B799IH05A ), an alkylating DNA da mage repair inhibitor, having molecular formula C 15 H18 O3, and/or ( ii ) any salt, free acid, free base, clath rate, solvate, hydrate, hemihydrate, anhydride, chelate, conformer, congener, crystal fo rm, crystal habit, polymorph, amorphous solid, homolog, isomer, stereoisomer, enantiomer, racemate, prodrug, isotopic or radiolabeled equivalent, complex or mixture of any of the foregoing with res pect to Irofulven that has the same mechanism of action as Irofulven . For clarity, Irofulven include s the active pharmaceutical ingredient known as irofulven, together with any salt, free acid, free base, clathrate, solvate, hydrate, hemihydrate, anh ydride, chelate, conformer, congener, crystal form, crystal habit, polymorph, amorphous solid, homolog, isomer, stereoisomer, enantiomer, racemate, prodrug, isotop ic or radiolabeled equivalent, complex or mixture thereof . For the purposes of the Agreement and this Addendum, Irofulven does not include Irofulven bound directly or via a linker to a Conjugate, Irof ulven Analogues irrespective of whether bound direc tly or via a linker to a Conjugate or illudin bound dir ectly or via a linker to a Conjugate or acylfulvene bound directly or via a linker to a Conjugate, including an illudin analogue bound directly or via a linker to a Conjugate, or acylfulvene analogue bound directly o r via a linker to a Conjugate