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                                                                    Exhibit 10.2


                                 April 29, 2001

Aurora Biosciences Corporation
11010 Torreyana Road
San Diego, CA 92121

Re:      Stockholder Agreement

Gentlemen:

         The undersigned (the "Stockholder") owns of record and beneficially the
number of shares (the "Shares") of common stock of Vertex Pharmaceuticals
Incorporated, a Massachusetts corporation ("Acquiror"), as set forth below. It
is contemplated that Acquiror, Aurora Biosciences Corporation, a Delaware
corporation ("Target") and Ahab Acquisition Sub, Inc., a Delaware corporation
and a newly organized wholly owned subsidiary of Acquiror ("Merger Sub"), will
enter into an Agreement and Plan of Merger (the "Agreement") with respect to the
merger (the "Merger") of Merger Sub with and into Target. Pursuant to the
Merger, each outstanding share of Target common stock will be converted into the
right to receive shares of Acquiror's common stock, all as more specifically
provided in the Agreement. The Stockholder wishes to facilitate the proposed
Merger and acknowledges that the proposed Merger will benefit the Stockholder.

         In consideration of the foregoing, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, and
intending to be legally bound hereby, the Stockholder agrees as follows:

         1.       STANDSTILL. The Stockholder agrees that, until the earlier of
the Effective Time (as defined in the Agreement), or the termination of the
Agreement in accordance with its terms, Stockholder shall not offer, sell,
contract to sell, transfer or otherwise dispose of, or grant any option to
purchase, or convert, any of the Shares. The restrictions on transfer contained
in this Paragraph 1 shall not apply to transfers by the Stockholder (i) to the
Stockholder's spouse, children or other member of the Stockholder's immediate
family, or a trust for the benefit of such persons, (ii) to the trustee or
trustees of a trust revocable solely by the Stockholder, (iii) to the
Stockholder's guardian or conservator, or (iv) in the event of the Stockholder's
death, to the Stockholder's executor(s), administrator(s) or trustee(s) under
the Stockholder's will (collectively, the "Permitted Transferees"); provided,
however, that in any such event the Shares so transferred in the hands of each
such Permitted Transferee shall remain subject to the provisions of this
Agreement, and each such Permitted Transferee shall so acknowledge in writing as
a condition precedent to the effectiveness of such transfer. As security for the
Stockholder's obligations under this paragraph, the Stockholder hereby assigns
to and grants to Target a lien upon and a security interest in the Shares.

         2.       PROXY.

         (a)      As further security for the Stockholder's obligations under
paragraph 1, the Stockholder hereby (i) revokes any previous proxies relating to
the Shares and (ii) irrevocably appoints, Stuart Collinson, Chairman, Chief
Executive Officer and President of the Target, Tom Klopack, Senior Vice
President and Chief Operating Officer of the Target, and Chris Krueger, General
Counsel and Vice President, Strategic Alliances of the Target, and each of them,
attorneys and proxies, with power of substitution in each of them, of the
Stockholder to (w) attend any and all meetings (and at all adjournments,
continuations or postponements, thereof) (the "Meeting(s)") of the stockholders
of Acquiror at which the Merger is presented for approval of such stockholders,
(x) represent the Stockholder at any such Meeting(s), (y) vote the Shares in
favor of the Merger on the terms set forth in the Agreement as executed (with
such changes as are not material to the rights of the Stockholder in the Merger)
at any such Meeting(s) and to vote the Shares in favor of other matters in
connection therewith, and (z) otherwise act for the Stockholder in the same
manner and with the same effect as if the Stockholder were personally present at
such Meeting(s) and voting the Shares or personally acting on any matters in
connection with the Merger submitted to the stockholders of Acquiror for
approval or consent (including executing waivers and consents in connection with
the Merger). Stuart Collinson, Tom Klopack and Chris Krueger hereby agree that
they shall vote the Shares at any such Meeting(s) in favor of the Merger on the
terms set forth in the Agreement as executed (with such changes as are not
material to the rights of the Stockholder in the Merger), and with respect to
other matters in connection therewith, provided, however, that the Target's
conditions to closing set forth in the Agreement have been satisfied.

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         (b)      The Stockholder authorizes such proxies to substitute any
other person or persons to act hereunder, to revoke any such substitution and to
file this proxy and any such substitution or revocation with the Secretary of
Acquiror.

         (c)      THIS PROXY IS IRREVOCABLE AND COUPLED WITH AN INTEREST AND
SHALL TERMINATE ON THE EARLIER OF THE EFFECTIVE TIME OR THE TERMINATION OF THE
AGREEMENT PURSUANT TO THE TERMS THEREOF.

         3.       REPRESENTATIONS AND WARRANTIES BY STOCKHOLDER. The Stockholder
represents and warrants to Target that:

         (a)      the Stockholder has all necessary power and authority to
execute this letter agreement including the proxy appointment contained herein;

         (b)      this letter agreement and proxy has been duly executed and
delivered by the Stockholder and constitutes a valid and binding agreement of
the Stockholder, enforceable in accordance with its terms; and

         (c)      neither the execution nor delivery of this letter agreement
and proxy by the Stockholder will (i) require the consent, waiver, approval,
license or authorization, or any filing with, any person or public authority,
(ii) with or without the giving of notice or the lapse of time, or both,
conflict with or constitute a violation of, or default under, or give rise to
any right of acceleration under any indenture, contract, commitment, agreement,
arrangement or other instrument of any kind to which the Stockholder is a party
or by which the Stockholder is bound, or (iii) violate any applicable law, rule,
regulation, judgment, order or degree of any governmental instrumentality or
court having jurisdiction over the Stockholder.

         4.       MISCELLANEOUS. The Stockholder will not take any action that
would prevent or frustrate Target's rights under the Agreement.



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         IN WITNESS WHEREOF, the Stockholder has executed this agreement and
proxy as of the date and year first above written.


                                    STOCKHOLDER:

                                    (Individual)

                                    /s/ Joshua Boger
                                    --------------------------------------------
                                    Print Name: Joshua Boger
                                                --------------------------------


                                    (Entity)


                                    --------------------------------------------
                                    By:
                                       -----------------------------------------
                                       Name:
                                            ------------------------------------
                                       Title:
                                             -----------------------------------

                                    Number of Shares of
                                    Common Stock  1,063,751  1,646,198 (OPTIONS)
                                                --------------------------------


The undersigned hereby acknowledges their obligation to vote the Shares at any
Meeting(s) in favor of the Merger as provided in Section 2(a) hereof.


/s/ Stuart Collinson
------------------------------
Stuart Collinson

/s/ Tom Klopack
------------------------------
Tom Klopack

/s/ C. W. Krueger
------------------------------
Chris Krueger

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                     Schedule of Other Stockholders Signing
                       This Form of Stockholder Agreement


Bruce I. Sachs
Charles A. Sanders
Donald R. Conklin
John Alam
Lynne Brum
Iain Buchanan
Roger W. Brimblecombe
Elaine Ullian
Vicki Sato
Barry M. Bloom