definiens: means Know - How that ( a ) is Controlled by EPIZYME as of the Prior AgreementEffective Date or at any time thereafter prior to the expiration of the Target Exclusivity Period, ( b ) arises outside of theCollaboration, and ( c ) is necessary or reasonably useful for the Development, Manufacture or Commercialization ofLicensed Compounds and Licensed Products in the Field in the Territory, but expressly excluding any Know - HowControlled by EPIZYME that relates to any compound or molecule that is not a Compound directed to EZH2 . Forpurposes of clarity, EPIZYME Know - How includes Diagnostic Know - How Controlled by EPIZYME as of the PriorAgreement Effective Date or at any time thereafter prior to the expiration of the Target Exclusivity Period, butexcludes Collaboration Know - How owned by EPIZYME and EPIZYME ’s interest in any Joint Know - How