definiens: means a [ protein, and any orthologues, or deletionai, substitutionaJ and/or insertional variants, or fragments of any of the foregoing that may be used as a surrogate for such protein or any of its lsoforms in the Research Program ], for which [COMPANY] shall develop small molecule inhibitors under the Research Program, in accordance with the provisions of this Agreement ; provided, however, inclusion of [ such surrogates ] shall be subject to the consent of both Parties, which consent shall not be unreasonably withheld . The specific Collaboration Targets that are included in the Research Plan at any given time may be - 2 -11146403 Confidential Treatment bas been Req uested of Marked Portions changed in accordance with Section 2.6(a ), but once a Collaboration Target has been included in the Research Plan, it shall continue to be a Collaboration Targe~ even ifno further research with respect to such Collaboration Target is performed under the Research Plan ; provided, however, if a Collaboration Target is abandoned in accordance with Section 2.6(b ), it shall thereafter cease to be a Collaboration Target