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                                                                   EXHIBIT 10.15

                              EMPLOYMENT AGREEMENT
                                (Susan Whoriskey)

         This Employment Agreement dated as of April 10, 2002 (this "Agreement")
is made by and between Mimeon, Inc., a Delaware corporation (the "Company"), and
Susan Whoriskey ("Employee").

         WHEREAS, Employee has been a consultant of the Company since September
25, 2001; and

         WHEREAS, the Company wishes to employ Employee and Employee desires to
be an employee of the Company;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements herein contained, the parties hereto agree as follows:

         1.       EMPLOYMENT. The Company hereby employs Employee to perform
those duties and services as the Company shall from time to time set forth, and
Employee accepts employment with the Company, upon the terms and conditions
hereinafter set forth. Employee shall serve as Vice President Licensing and
Business Development of the Company and shall report to the Chief Executive
Officer of the Company. The Chief Executive Officer shall have the right to
review and change the responsibilities of Employee from time to time as he or
she may deem necessary or appropriate provided that such responsibilities are
reasonably consistent with a vice president level position. The Chief Executive
Officer may elect, at his or her discretion, to change the reporting
relationship for Employee.

         2.       DUTY TO PERFORM SERVICES.  Employee shall devote her full time
during normal business hours four days per week to rendering services to the
Company hereunder, and shall exert all reasonable efforts in the rendering of
such services.

         Employee agrees that in the rendering of all services to the Company
and in all aspects of employment hereunder, she shall comply in all material
respects with all directives, policies, standards and regulations from time to
time established by the Company, to the extent they are not in conflict with
this Agreement.

         3.       TERM OF AGREEMENT.  There shall be no definite term of
employment, and Employee shall be an employee at will. The Company may terminate
Employee's employment with the Company at any time with or without Cause (as
defined in Section 17(e) ).

         4.       COMPENSATION.

                  (a)      BASE SALARY. Commencing as of January 1, 2002, and
throughout the term of this Agreement, the Company shall pay Employee a base
salary, payable in equal installments in accordance with the Company's standard
schedule for salary payments to its employees, at an annual rate equal to
$140,000. Employee's base salary shall be reviewed by the Company at least once
every six months, and may be adjusted on or after each such review as mutually
agreed upon by the Company and Employee.

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                  (b)      EQUITY INCENTIVES.

                           (i)      NON-STATUTORY STOCK OPTION.  Pursuant to an
offer letter dated September 18, 2001, from the Company to the Employee, the
Company shall grant to Employee, effective January 1, 2002, a non-statutory
stock option ("NSO") to purchase 2,933 shares of the Company's common stock,
$.0001 par value per share ("Common Stock"), at an exercise price per share
equal to $0.10 per share (which was the fair market value per share on the date
of grant). One half of the shares of Common Stock issuable upon exercise of the
NSO shall be fully vested as of the effective date of the NSO and the balance
shall vest on March 25, 2002.

                           (ii)     RESTRICTED STOCK.  Simultaneous with the
execution of this Agreement, the Company shall sell to Employee 70,477 shares
(the "Shares") of Common Stock at a price per of $0.17 per Share, which is the
current fair market value per share. The purchase and sale of Shares shall be
governed by a Restricted Stock Purchase Agreement, which shall contain, among
other things, a right of the Company to repurchase unvested Shares under certain
circumstances. The Shares shall vest in accordance with the vesting schedule set
forth on SCHEDULE A.

                  (c)      BONUSES.

                           (i)      SIGNING BONUS.  Promptly after the Company
and Employee sign this Agreement, the Company shall pay Employee a signing bonus
of $20,000 in cash.

                           (ii)     YEAR-END BONUS.  If the performance goals
set forth in SCHEDULE B (as the same may be modified from time to time in a
writing signed by the Employee and the Employee's supervisor, the "Performance
Goals") are achieved by December 31, 2002, then the Company shall pay Employee a
bonus of $30,000 in cash by March 1, 2003; PROVIDED, however, that the Company
shall pay Employee a bonus of less than $30,000 if only some of the Performance
Goals have been achieved or if some of the Performance Goals have been partially
achieved; and PROVIDED, further, however, that the amount of the bonus may be
increased by the Chief Executive Officer, after consultation with the
Compensation Committee of the Board of Directors if appropriate, based on other
considerations deemed relevant by the Chief Executive Officer at or about the
time that the bonus is to be awarded. The determination of whether or not a
Performance Goal has been achieved shall be made by the Chief Executive Officer
in his or her sole discretion.

         5.       VACATIONS AND HOLIDAYS; BENEFITS.

                  (a)      VACATION AND HOLIDAYS.  Employee shall be entitled to
15 paid vacation days annually and shall not be required to work but shall be
paid for all major U.S. holidays.

                  (b)      BENEFITS. Employee and, to the extent applicable,
Employee's family, dependents and beneficiaries, shall be entitled to receive
medical and dental insurance coverage through the Company, and such other
benefits, including 401(k) plan, life insurance and disability insurance, as may
be provided by the Company to its other similarly situated senior executives
from time to time (collectively, the "Benefits").

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         6.       EXPENSES.  The Company shall pay or reimburse Employee for all
reasonable business expenses incurred by Employee in connection with her
employment by the Company in accordance with the Company's policies in effect
from time to time.

         7.       CONFIDENTIAL INFORMATION. While employed by the Company and
thereafter, Employee shall not, except as otherwise required pursuant to court
order, directly or indirectly, use any Confidential Information (as defined
below) other than pursuant to her employment by and for the benefit of the
Company, or disclose any Confidential Information to anyone outside of the
Company, whether by private communication, public address, publication or
otherwise, or disclose any Confidential Information to anyone within the Company
who has not been authorized to receive such information, except as directed in
writing by an authorized representative of the Company. The term "Confidential
Information" as used throughout this Agreement shall mean all trade secrets,
proprietary information, and other data or information (and any tangible
evidence, record or representation thereof), whether prepared, conceived or
developed by a consultant or employee of the Company (including Employee) or
received by the Company from an outside source, which is in the possession of
the Company (whether or not the property of the Company), and which is
maintained in confidence by the Company. Without limiting the generality of the
foregoing, Confidential Information shall include:

                  (a)      any idea, improvement, invention, innovation,
development, technical data, design, formula, device, pattern, sequence,
concept, art, method, process, machine, manufacturing method, composition of
matter, computer program or software, source code, object code, algorithm,
model, diagram, flow chart, product specification or design, plan for a new or
revised product, sample, compilation of information, or work in process, and any
and all revisions and improvements relating to any of the foregoing (in each
case whether or not reduced to tangible form); and

                  (b)      the name of any employee, consultant, customer or
prospective customer, any sales plan, marketing material, plan or survey,
business plan or opportunity, product or development plan or specification,
business proposal, financial record, or business record or other record or
information relating to the present or proposed business of the Company.

         Notwithstanding the foregoing, the term Confidential Information shall
not apply to information which the Company has voluntarily disclosed to the
public without restriction, or which has otherwise lawfully entered the public
domain.

         Employee acknowledges that the Company from time to time has in its
possession information which is claimed by customers and others to be
proprietary and which the Company has agreed to keep confidential. Employee
agrees that all such information shall be Confidential Information for purposes
of this Agreement.

         8.       OWNERSHIP AND ASSIGNMENT OF INTELLECTUAL PROPERTY. Employee
agrees that all originals and all copies of materials containing, representing,
evidencing, recording, or constituting any Confidential Information, however and
whenever produced (whether by Employee or others) shall be the sole property of
the Company.

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         Employee agrees that all Confidential Information and all other
discoveries, inventions, ideas, specifications, designs, concepts, research and
other information, processes, products, methods and improvements, or parts
thereof conceived, developed, or otherwise made by him, alone or jointly with
others and in any way relating to the Company's present or proposed products,
programs or services or to tasks assigned to her during the course of her
employment, whether or not patentable or subject to copyright protection and
whether or not reduced to tangible form or reduced to practice, during the
period of her employment with the Company, whether or not made during my regular
working hours, and whether or not made on the Company's premises, and whether or
not disclosed by her to the Company (hereinafter referred to as "Intellectual
Property") together with all products or services which embody or emulate any
Intellectual Property shall belong exclusively to the Company.

         Employee agrees to, and hereby does, assign to the Company all her
right, title and interest throughout the world in and to all Intellectual
Property and to anything tangible which evidences, incorporates, constitutes,
represents or records any Intellectual Property. Employee agrees that all
Intellectual Property shall constitute works made for hire under the copyright
laws of the United States and hereby assigns and, to the extent any such
assignment cannot be made at present, Employee hereby agrees to assign to the
Company all copyrights, patents and other proprietary rights Employee may have
in any Intellectual Property, together with the right to file for and/or own
wholly without restriction United States and foreign patents, trademarks, and
copyrights. Employee agrees to waive, and hereby waives, all moral rights or
proprietary rights in or to any Intellectual Property and, to the extent that
such rights may not be waived, agrees not to assert such rights against the
Company or its licensees, successors or assigns.

         Employee hereby certifies that SCHEDULE C, sets forth any and all
confidential information and intellectual property that Employee claims as her
own or otherwise intends to exclude from this Agreement because it was developed
by her prior to the date of this Agreement. Employee understands that after
execution of this Agreement she shall have no right to exclude Confidential
Information or Intellectual Property from this Agreement.

         9.       EMPLOYEE'S OBLIGATION TO KEEP RECORDS. Employee shall make and
maintain adequate and current written records of all Intellectual Property,
including notebooks and invention disclosures, which records shall be available
to and remain the property of the Company at all times. Employee shall disclose
all Intellectual Property promptly, fully and in writing to the Company
immediately upon production or development of the same and at any time upon
request.

         10.      EMPLOYEE'S OBLIGATION TO COOPERATE. Employee will, at any time
during her employment, or after it terminates, upon request of the Company,
execute all documents and perform all lawful acts which the Company considers
necessary or advisable to secure its rights hereunder and to carry out the
intent of this Agreement. Without limiting the generality of the foregoing,
Employee will assist the Company in any reasonable manner to obtain for its own
benefit patents or copyrights in any and all countries with respect to all
Intellectual Property assigned pursuant to Section 8, and Employee will execute,
when requested, patent and other applications and assignments thereof to the
Company, or Persons (as defined in Section 17(f)) designated by it, and any
other lawful documents deemed necessary by the Company to carry out

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the purposes of this Agreement, and Employee will further assist the Company in
every way to enforce any patents and copyrights obtained, including testifying
in any suit or proceeding involving any of said patents or copyrights or
executing any documents deemed necessary by the Company. It is understood that
(i) reasonable out-of-pocket expenses of Employee's assistance incurred at the
request of the Company under this Section will be reimbursed by the Company, and
(ii) if Employee is required to assist the Company pursuant to this Section at a
time when Employee is no longer an employee of the Company, then the Company
will pay Employee a fee at an hourly rate commensurate with her salary as of the
last day of her employment.

         11.      NONCOMPETITION. Subject to written waivers that maybe provided
by the Company upon request, which shall not be unreasonably withheld, Employee
agrees that during the term of this Agreement and for a period of 12 months
after the termination of this Agreement (the "Restricted Period"), Employee
shall not directly or indirectly (i) provide any services in the Field of
Interest (as defined in Section 17(e)) to any Person other than the Company,
(ii) become an owner, partner, shareholder, consultant, agent, employee or
co-venturer of any Person that has committed, or intends to commit, significant
resources to the Field of Interest.

         12.      NONSOLICITATION. During the Restricted Period, Employee shall
not (i) solicit, encourage, or take any other action which is intended to induce
any employee of, or consultant to, the Company (or any other Person who may have
been employed by, or may have been a consultant to, the Company during the term
of Employee's employment) to terminate his or her employment or relationship
with the Company in order to become employed by or otherwise perform services
for any other Person or (ii) solicit, endeavor to entice away from the Company
or otherwise interfere with the relationship of the Company with any Person who
is, or was within the then-most recent 12 month period, a client or customer of
the Company.

         13.      RETURN OF PROPERTY. Upon termination of Employee's employment
with the Company, or at any other time upon request of the Company, Employee
shall return promptly any Confidential Information, including all customer or
prospective customer lists, other customer or prospective customer information
or related materials, computer programs, software, electronic data,
specifications, drawings, blueprints, medical devices, samples, reproductions,
sketches, notes, notebooks, memoranda, reports, records, proposals, business
plans, or copies of them, other documents or materials, tools, equipment, or
other property belonging to the Company or its customers which Employee may then
possess or have under her control. Employee further agrees that upon termination
of her employment she shall not take with her any documents or data in any form
or of any description containing or pertaining to Confidential Information or
Intellectual Property.

         14.      OTHER OBLIGATIONS.

                  (a)      Employee hereby represents, warrants and agrees (i)
that Employee has the full right to enter into this Agreement and perform the
services required of her hereunder, without any restriction whatsoever; (ii)
that in the course of performing services hereunder, Employee will not violate
the terms or conditions of any agreement between her and any third party or
infringe or wrongfully appropriate any patents, copyrights, trade secrets or
other intellectual property rights of any Person anywhere in the world; (iii)
that Employee has not and

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will not disclose, except as required pursuant to a court order, or use during
her employment by the Company any confidential information that she acquired as
a result of any previous employment or consulting arrangement or under a
previous obligation of confidentiality; and (iv) that Employee has disclosed to
the Company in writing any and all continuing obligations to previous employers
or others that require her not to disclose any information to the Company.

                  (b)      Employee acknowledges that the Company from time to
time may have agreements with other Persons, including the government of the
United States or other countries and agencies thereof, which impose obligations
or restrictions on the Company regarding inventions made during the course of
work thereunder or regarding the confidential nature of such work. Employee
agrees to be bound by all such obligations and restrictions which are made known
to her and to take all action necessary to discharge the obligations of the
Company thereunder.

         15.      TERMINATION EVENT. The following events shall each be
considered a "Termination Event" and, upon the occurrence of any of them, shall
have the effect of immediately terminating the Company's obligations under this
Agreement, including its obligation to make any further payments hereunder but
excluding the payment of base salary and vacation benefits which are accrued at
the date of termination:

                  (a)      Employee's death;

                  (b)      Employee's Disability for such period of time and
under circumstances which would constitute a Long Term Disability;

                  (c)      The termination of Employee's employment by the
Company for Cause (as defined in Section 17(e) ). Termination pursuant to
Section 15(c) shall be without prejudice to any other right or remedy to which
the Company may be entitled, at law, in equity, under this Agreement or
otherwise; or

                  (d)      The termination of Employee's employment by Employee
for any reason.

         Notwithstanding Employee's termination of employment pursuant to
Section 15(b), 15(c) or 15(d), Employee's covenants and obligations set forth in
Sections 7, 8, 10, 11, 12 and 13 shall remain in effect and be fully enforceable
in accordance with the provisions thereof.

         16.      TERMINATION WITHOUT CAUSE.  In addition to the other
termination rights provided to the Company or Employee hereunder, the Company
may terminate Employee's employment without Cause at any time; PROVIDED,
however, that:

                  (a)      Employee's covenants and obligations set forth in
Sections 7, 8, 9, 10, 11, 12 and 13 shall remain in effect and be fully
enforceable in accordance with the provisions thereunder; and

                  (b)      in the event that Employee's employment is terminated
by the Company without Cause at any time after January 1, 2003, Employee shall
be entitled to receive (i) the installments of base salary set forth in Section
4(a) not yet paid to such Employee, payable when

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and as if Employee had continued to be employed by the Company until the three
month anniversary of the date of such termination, and (ii) the benefits set
forth in Section 5(b) for such period of time.

         17.      MISCELLANEOUS.

                  (a)      ENTIRE AGREEMENT. This Agreement constitutes the
entire agreement among the parties with respect to the subject matter hereof and
supersede all other prior agreements and understandings, both written and oral,
between the parties with respect to such subject matter, including the offer
letter dated September 18, 2001, from the Company to Employee.

                  (b)      ASSIGNABILITY, ETC. This Agreement shall be binding
upon and inure to the benefit of the parties hereto and their respective
successors and permitted assigns. This Agreement is not intended to confer upon
any Person other than the parties hereto any rights or remedies hereunder,
except as otherwise expressly provided herein and shall not be assignable by
operation of law or otherwise.

                  (c)      AMENDMENTS AND SUPPLEMENTS.  This Agreement may not
be altered, changed or amended, except by an instrument in writing signed by the
parties hereto.

                  (d)      NO WAIVER. The terms and conditions of this Agreement
may be waived only by a written instrument signed by the party waiving
compliance. In the case of the Company, no waiver shall be effective unless
approved by the Board. The failure of any party hereto to enforce at any time
any of the provisions of this Agreement shall in no way be construed to be a
waiver of any such provision, nor in any way to affect the validity of this
Agreement or any part hereof or the right of such party thereafter to enforce
each and every such provision. No waiver of any breach of or non-compliance with
this Agreement shall be held to be a waiver of any other or subsequent breach or
non-compliance.

                  (e)      CERTAIN DEFINITIONS.  For purposes of this Agreement,
the following terms shall have the meanings set forth below:

                  "Cause" means:

                           (i)      Employee's dishonesty with respect to the
Company;

                           (ii)     Employee's misconduct which materially and
adversely reflects upon the business, affairs, operations, or reputation of the
Company or upon Employee's ability to perform her duties for the Company;

                           (iii)    Employee's failure (except by reason of
Disability) to perform her duties and responsibilities for the Company, which
failure continues for more than ten days after the Company gives written notice
to Employee which sets forth in reasonable detail the nature of such failure;

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                           (iv)     Employee's negligent performance of her
duties, which negligent performance continues for more than ten days after the
Company gives written notice to Employee which sets forth in reasonable detail
the nature of such negligence; or

                           (v)      Employee's breach of any one or more of the
material provisions of this Agreement, which breach continues for more than ten
days after the Company gives written notice to Employee which sets forth in
reasonable detail the nature of such breach.

                  "Disability" means the inability of Employee to substantially
perform her duties to the Company by reason of any medically determinable
physical impairment.

                  "Field of Interest" means the field of sequencing, chemical,
enzymatic or biological synthesis, production or modification of linear and
branched sugars and glycoconjugates.

                  "Long Term Disability" means a Disability which continues for
at least 120 consecutive calendar days or 150 calendar days during any
consecutive twelve-month period, after its commencement, and is determined in
good faith to be total and permanent by the Board following consultation with
reputable medical or health experts selected by the Board.

                  "Person" shall mean an individual, a corporation, an
association, a partnership, an estate, a trust and any other entity or
organization.

                  (f)      CONSTRUCTION OF AGREEMENT. A reference to a Section
or Exhibit shall mean a Section in or Exhibit to this Agreement unless otherwise
expressly stated. The titles and headings herein are for reference purposes only
and shall not in any manner limit the construction of this Agreement which shall
be considered as a whole. The words "include," "includes" and "including" when
used herein shall be deemed in each case to be followed by the words "without
limitation."

                  (g)      NOTICE. All notices and other communications
hereunder shall be in writing and shall be deemed given if delivered by hand,
sent by facsimile transmission with confirmation of receipt, sent via a
reputable overnight courier service with confirmation of receipt requested, or
mailed by registered or certified mail (postage prepaid and return receipt
requested) to the parties at the following addresses (or at such other address
for a party as shall be specified by like notice), and shall be deemed given on
the date on which delivered by hand or otherwise on the date of receipt as
confirmed:

         To the Company:

                  Mimeon, Inc.
                  43 Moulton Street
                  Cambridge, MA 02143
                  Attention:  President
                  Fax:  617.491.9701

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         To Employee:

                  Susan Whoriskey
                  47 Louise Road
                  Belmont, MA 02478

                  (h)      GOVERNING LAW.  This Agreement shall be, governed by,
and construed and enforced in accordance with, the substantive laws of The
Commonwealth of Massachusetts, without regard to its principles of conflicts of
laws.

                  (i)      REMEDIES. Employee recognizes that money damages
alone would not adequately compensate the Company in the event of breach by
Employee of this Agreement, and Employee therefore agrees that, in addition to
all other remedies available to the Company at law, in equity or otherwise, the
Company shall be entitled to injunctive relief for the enforcement hereof. All
rights and remedies hereunder are cumulative and are in addition to and not
exclusive of any other rights and remedies available at law, in equity, by
agreement or otherwise.

                  (j)      SURVIVAL; VALIDITY. Except as expressly provided
herein, the provisions of this Agreement shall not survive termination of
Employee's employment by the Company for any reason. In the event that any
provision of this Agreement shall be determined to be unenforceable by reason of
its extension for too great a period of time or over too large a geographic area
or over too great a range of activities, it shall be interpreted to extend only
over the maximum period of time, geographic area or range of activities as to
which it may be enforceable. If, after application of the preceding sentence,
any provision of this Agreement shall be determined to be invalid, illegal or
otherwise unenforceable by a court of competent jurisdiction, the validity,
legality and enforceability of the other provisions of this Agreement shall not
be affected thereby. Except as otherwise provided in this Section 17, any
invalid, illegal or unenforceable provision of this Agreement shall be
severable, and after any such severance, all other provisions hereof shall
remain in full force and effect.

                  (k)      COUNTERPARTS.  This Agreement may be executed in one
or more counterparts, all of which together shall constitute one and the same
Agreement.

                                    * * * * *

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         IN WITNESS WHEREOF, the parties have caused this Employment Agreement
to be executed as an agreement under seal as of the date first written above.

                                    MIMEON, INC.

                                    By:  /s/ Alan L. Crane
                                       -----------------------------------------
                                       Alan L. Crane
                                       President and Chief Executive Officer


                                         /s/ Susan Whoriskey
                                       -----------------------------------------
                                       Susan Whoriskey

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