definiens: shall mean, on a product - by - product and country - by - basis, the period oftime commencing on the date of first commercial sale of the Product in a given country and ending on the later ofthe date that is : ( a ) ten ( 10 ) years after the date of the first commercial sale of the Product in such country ; or ( b)with respect to ( i ) the First Antibody, the expiration of the last to expire, to lapse, or to be abandoned of any ValidClaim in the Patent Rights in the Enumeral IP that cover the manufacture, use, offer for sale, sale or import of theProduct that are filed as of the Effective Date, or that claim priority from the Patent Rights in the Enumeral IP thatcover the manufacture, use, offer for sale, sale or import of the Product that are filed as of the Effective Date, and(ii ) each Subsequent Antibody, the expiration of the last to expire, to lapse, or to be abandoned of any Valid Claimin the Patent Rights in the Enumeral IP that cover the manufacture, use, offer for sale, sale or import of theProduct that are filed as of the Option Exercise Date for such Subsequent Antibody, or that claim priority from thePatent Rights in the Enumeral IP that cover the manufacture, use, offer for sale, sale or import of the Product thatare filed as of the Option Exercise Date for such Subsequent Antibody