definiens: means any challenge to the validity or enforceability of any of the [COMPANY] Patent Rights, TargaceptProgram Patent Rights or Joint Program Patent Rights, including by : ( a ) filing a declaratory judgment action in which any ofthe [COMPANY] Patent Rights, [COMPANY] Program Patent Rights or Joint Program Patent Rights is alleged to be invalid orunenforceable ; ( b ) citing prior art pursuant to 35 U.S.C. § 301 or filing a request for re - examination of any of the TargaceptPatent Rights, [COMPANY] Program Patent Rights or Joint Program Patent Rights pursuant to 35 U.S.C. § 302 or § 311 ( withoutthe prior written consent of [COMPANY] ) ; ( c ) provoking or becoming party to an interference with an application for any of theTargacept Patent Rights, [COMPANY] Program Patent Rights or Joint Program Patent Rights pursuant to 35 U.S.C. § 135 ; or(d ) filing or commencing any re - examination ( without the prior written consent of [COMPANY] ), opposition, cancellation, nullity or similar proceedings against any of the [COMPANY] Patent Rights, [COMPANY] Program Patent Rights or Joint ProgramPatent Rights in any country