definiens: shall mean ( x ) costs and expenses incurred by a Partyfor REGN2810, from and after the Effective Date directly in connection with the Development ofREGN2810 in the Field in accordance with this Agreement and the REGN2810 GlobalDevelopment Plan, ( y ) costs and expenses ( including any Program Costs ) incurred by a Party foreach other IO Licensed Product that was not a Tail Early Opt - In Antibody, from and after the first(1st ) day of the month in which the Opt - In Notice for such IO Licensed Product is received byRegeneron pursuant to Article 5 of the IO Discovery Agreement, and ( z ) costs and expenses(including any Program Costs ) incurred by a Party for each other IO Licensed Product that was aTail Early Opt - In Antibody, from and after the first ( 1st ) day of the month in which the Tail POCReport for such IO Licensed Product is delivered by Regeneron pursuant to Article 5 of7Certain portions of this Exhibit have been omitted pursuant to a request for confidentiality . Such omitted portions, which are marked with brackets and three asterisks [ * * * ], have been separately filed with the Commission