definiens: means any challenge to the validity or enforceability of any of the SYNTA Patent Rights, including ( except as provided below ) by ( a ) filing a declaratory judgment action in which any of the SYNTA Patent Rights isalleged to be invalid or unenforceable ; ( b ) citing prior art pursuant to 35 U.S.C. § 301, filing a request for re - examination ofany of the SYNTA Patent Rights pursuant to 35 U.S.C. § 302 and/or § 311, or provoking or becoming a party to an interferencewith an application for any of the SYNTA Patent Rights pursuant to 35 U.S.C. § 135 ; or ( c ) filing or commencing any re - examination, opposition, cancellation, nullity or similar proceedings against any of the SYNTA Patent Rights in any country;provided, that shall not include filing requests for re - examination of SYNTA Patent Rights or re - issue of SYNTAPatent Rights to the extent that JPC agrees that such actions are in the best interest of the applicable SYNTA Patent Rights