definiens: means ( a ) with respect to the relevant Licensed Product, for any country, the period(i ) commencing on the First Commercial Sale of the first Licensed Product in such country and ( ii ) expiring on the laterof ( x ) the tenth ( 10th ) anniversary of such First Commercial Sale and ( y ) the expiration of the last to expire ValidClaim of an issued [COMPANY] Patent in such country that Covers the sale of the relevant Licensed Product in suchcountry, and ( b ) with respect to the relevant Follow - On Product, for any country, the period ( i ) commencing on theFirst Commercial Sale of the first Follow - On Product in such country and ( ii ) expiring on the later of ( x ) the tenth ( 10th)anniversary of such First Commercial Sale and ( y ) the expiration of the last to expire Valid Claim of an issuedMedImmune Patent in such country that Covers the sale of the relevant Follow - On Product in such country