definiens: shall mean any of the following : ( a ) Except as otherwise provided in Section 3.6 of this Agreement, a HDAC Inhibitor Compound first synthesized byNIBRI or its Affiliates outside of the collaboration contemplated by the Collaboration Agreement and for which NIBRI orits Affiliates have received or have applied for or could reasonably expect to apply for and receive U.S. composition ofmatter patent coverage and that : ( a ) is shown to have an IC50 of less than or equal to 1 mM ( micromolar ) in any standardNIBRI in vitro assay for the inhibition of HDAC activity ; and ( b ) has been designated a candidate forfollow - up under the designation in accordance with the standard drug development terminologyused by NIBRI ; and ( b ) Except as otherwise provided in Section 3.6 of this Agreement, a HDAC Inhibitor Compound licensed to, purchasedor otherwise acquired by NIBRI or its Affiliates from a Third Party for which ( i ) NIBRI or its Affiliates do not have anymaterial future license, royalty or similar payment obligations ( as determined in good faith by the JSC ), and ( ii ) the ThirdParty licensor or assignor or NIBRI or its Affiliates have received or have applied for or could reasonably expect to applyfor and receive U.S. composition of matter patent coverage and that ( a ) is shown to have an IC50 of less than or equal to 1mM ( micromolar ) in any standard NIBRI in vitro assay for the inhibition of HDAC activity ; and ( b ) has been designated a candidate for follow - up under the designation in accordance with the standard drugdevelopment terminology used by NIBRI ; and ( c ) Except as otherwise provided in Section 3.6 of this Agreement, all derivatives and analogs of the compoundsdescribed in subsections ( a ) and ( b ) above that are shown to have an IC50 of less than or equal to 100 nM ( nanomolar ) asdetermined by at least one standard in vitro assay for the inhibition of HDAC activity ; and ( d ) A HDAC Inhibitor Compound licensed to, purchased or otherwise acquired by NIBRI or its Affiliates from a ThirdParty for which NIBRI or its Affiliates have any material future license, royalty or similar payment obligation ( asdetermined in [ .. * * .. ] CONFIDENTIAL TREATMENT REQUESTED12 good faith by the JSC ) and all derivatives and analogs of the compounds described in this subsection ( d ) for which NIBRIor its Affiliates have any material future license, royalty or similar payment obligation ( as determined in good faith by theJSC ) ( collectively, )