Change In Control Agreement Limber 10/10/02

ACLARA BIOSCIENCES, INC.


1288 Pear Avenue, Mountain View, CA 94043


October 10, 2002


Joseph M. Limber 1515 Arriba Court Los Altos, CA 94024


Re: Change in Control Agreement


Dear Mr. Limber:


In connection with General Release and Separation Agreement entered into as of October 10, 2002 by you and ACLARA Biosciences, Inc. (the "Company"), the Company hereby agrees that after this letter agreement (this "Agreement") has been fully executed, you shall receive the severance benefits set forth in this Agreement in the event of a Hostile Takeover (as defined below) or a Change in Control (as defined below).


1. Term of Agreement. This Agreement shall commence on the date hereof and shall continue in effect through the termination of your service as an executive officer of the Company on December 1, 2002 or such earlier date as you and the Company shall agree in accordance with the General Release and Separation Agreement (such service to be referred to herein as "Service").


2. Change in Control/Hostile Takeover. You shall receive no benefits under this Agreement unless there has been a Change in Control or a Hostile Takeover.


(a) For purposes of this Agreement, a "Change in Control" shall mean (i) an acquisition of any voting securities of the Company (the "Voting Securities") by any "person" (as the term "person" is used for purposes of Section 13(d) or Section 14(d) of the Securities Exchange Act of 1934, as amended (the "1934 Act")) immediately after which such person has "beneficial ownership" (within the meaning of Rule 13d-3 promulgated under the 1934 Act) ("Beneficial Ownership") of 15% or more of the combined voting power of the Company's then outstanding Voting Securities without the approval of the Board; (ii) a merger or consolidation that results in more than 50% of the combined voting power of the Company's then outstanding Voting Securities of the Company or its successor changing ownership (whether or not approved by the Board); (iii) the sale of all or substantially all of the Company's assets; (iv) approval by the shareholders of the Company of a plan of complete liquidation of the Company; or (v) the individuals constituting the Board as of the date of this Agreement (the "Incumbent Board") cease for any reason to constitute at least 1/2 of the members of the Board; provided, however, that if the election, or nomination for election by the Company's stockholders, of any new director was approved by a vote of the Incumbent Board, such new director shall be considered a member of the Incumbent Board.


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(b) For purposes of this Agreement, a "Hostile Takeover" means a transaction or series of transactions that results in any person acquiring Beneficial Ownership of more than 50% of the combined voting power of the Company's then outstanding Voting Securities without the approval of the Board.


3. Acceleration of Vesting Upon Change of Control or Hostile Takeover. Upon a Change of Control or a Hostile Takeover during the term of this Agreement, you shall immediately become 100% vested with respect to any options to purchase the Company's capital stock that you then hold and/or any restrictions with respect to restricted shares of the Company's capital stock that you then hold shall immediately lapse.


4. Successors; Binding Agreement.


(a) The Company shall require any successor (whether direct or indirect, by purchase, merger, consolidation or otherwise) to all or substantially all of the business and/or assets of the Company to expressly assume and agree to perform this Agreement in the same manner and to the same extent that the Company would be required to perform it if no such succession had taken place. Unless expressly p ...