definiens: shall mean ( a ) a Proposed Antigen that is rejected by the TargetReview Committee during the Antigen Designation Term or by the Research Management Committee or AZ pursuantto Section 2.2.2(c ) or Section 2.2.2(d ) or, with respect to a Proposed Antigen that is the Advanced ABX Antigen or anAccelerated ABX Antigen, Section 2.2.1(j ), ( b ) subject to Section 2.2.4, a Proposed Antigen that has not beendesignated a Prioritized Antigen or Collaboration Antigen as of the expiration or earlier termination of the AntigenDesignation Term, ( c ) a Potential Co - Development Antigen that is rejected by AZ or is not designated as aCollaboration Antigen or a Co - Development Antigen within the applicable 21 time periods pursuant to Section 2.2.1(l ), ( d ) a Proposed Antigen that is replaced by AZ in order to substitute anotherAntigen as a Proposed Antigen in its place pursuant to Section 2.2.1(o ), ( e ) a Proposed Antigen that is withdrawn byAZ pursuant to Section 2.2.1(e ) or 4.17.2, or ( f ) subject to Section 2.2.1(e ), an Antigen that AZ fails to timelydesignate as a Proposed Antigen within the applicable time period pursuant to Section 2.2.1(e )