definiens: shall mean:(a ) in the case of a Lead Product, the period beginning on the first commercial sale of such Lead Product andending, on a Compound - by - Compound and country - by - country basis, upon ( a ) in the case of a Valid Claim Product, theexpiration of the last to expire patent containing a Valid Claim in the [COMPANY] Patents or Joint Patents ( excluding the GenentechPatents ) in such country or ( b ) in the case of a Know - How Product, [ * * ] years from the date of first sale ; and(b ) in the case of a [COMPANY] Product, the period beginning on the first commercial sale of such [COMPANY] Product andending, on a Compound - by - Compound and country - by - country basis, upon ( a ) in the case of a Valid Claim Product, theexpiration of the last to expire patent containing a Valid Claim in the [COMPANY] Patents or Joint Patents ( excluding the CurisCollaboration Patents ) in such country or ( b ) in the case of a Know - How Product, [ * * ] years from the date of first sale