definiens: means any person or ent ity who is an authorized end - user or intended recipient of Licensed Antibody Phage Display Materials ( including a CAT Library ), Licensed Immunoglobulins or Licensed Immunoglobulin Information transferred from CAT and/or a person or entity on whose behalf CAT knowingly engages in Antibody Phage Display ; provid ed, however, that except for the entities identified on Schedule 1.4 such person or entity shall not be deemed to be a CAT Collaborator unless and until th e requirements of Section 2.4 are complied with . An initial list of CAT Collabora tors with whom CAT has an agreement in full force and effect as of the Effect i ve Date is identified on Schedule 1.4 ; provided, that such entities are in c ompliance with all of the provisions of this Agreement applicable to CAT Coll aborators or will be within a reasonable time after the Effective Date . No person or entity shall be deemed to be a CAT Collaborator if such person or entity is e ngaged in a Commercial Antibody Phage Display Business unless, pursuant to a written agreement ( other than this Agreement ), executed after the Effective Date, XOMA has granted to such person or entity a valid license or covenant n ot to xxx under the XOMA Patent Rights which explicitly extends to the activ ities identified in this third sentence of Section 1.4 ; provided, that a CAT Collaborator listed in column ( a ) of Schedule 1.4 shall retain its status as such, notwithstanding that it may after the Effective Date engage in a Commerc ial Antibody Phage Display Business, but in all cases only with respect to act ivities of such CAT Collaborator that are carried out pursuant to and i n accordance with its arrangement with CAT and the applicable terms of th is Agreement using Licensed Antibody Phage Display Materials and/or Licensed I m munoglobulins provided by CAT . XOMA shall provide CAT prompt written notice o f those written agreements or covenants not to xxx which satisfy the requirements of the prior sentence