definiens: means all compounds that are identified by BII and arising under this Agreement, including any modifications, variations or derivatives thereof, including any metabolite, salt, ester, hydrate, solvate, isomer, enantiomer, free acid form, free base form, crystalline form, co -crystalline form, amorphous form, pro -drug ( including ester pro -drug ) form, racemate, polymorph, chelate, stereoisomer, tautomer, optically active form or any derivatives ; provided that, following cross -screening of suc h compounds by BII or by [COMPANY] in accordance with the Research Plan using its helicase or histone acetyl transferase cross -screening panels, BII will have the right to exclude up to [ * * ] Compounds that are shown through such cross -screening to be [ * * ] in hibitors and up to [ * * ] Compounds that are shown through such cross -screening to be [ * * ] inhibitors from the definition of BII Research Compounds upon written notice to [COMPANY] ( such written notices, collectively, the ) ; provided further that BII may periodically update the Excluded Compound List with other Compounds upon written notice to [COMPANY] ( but in no event may the Excluded Compound List identify more than [ * * ] inhibitors and [ * * ] inhibitors at any time ) and, upon each such update ( i ) Compounds that were previously included in the Excluded Compound List but that BII removes from the Excluded Compound List, shall be deemed to be BII Research Compounds and ( ii ) Compounds that were not previously included in the Excluded Compoun d List but that BII adds to the Excluded Compound List, shall be excluded from the definition of BII Research Compounds