definiens: means any challenge to the validity or enforceability of any of CARDIOME Patents, including by : .1 filing a declaratory judgment action in which any of CARDIOME Patents is alleged to be invalidor unenforceable ; .2 citing prior art pursuant to 35 U.S.C. § 301 against any of CARDIOME Patents, filing a request for re - examination of any of CARDIOME Patents pursuant to 35 U.S.C. § 302 and/or § 311, or becoming aparty to an interference, or providing assistance to a Third Party which has become a party to aninterference, with an application for any of CARDIOME Patents pursuant to 35 U.S.C. § 135 ; or .3 filing or commencing any re - examination, opposition, cancellation, nullity or similar proceedingsagainst any of CARDIOME Patents in any country