<PAGE>
 
                                                                   Exhibit 10.8


                                   AGREEMENT

     THIS AGREEMENT ("Agreement") is made as of the 23rd day of December, 1998,
by and among CuraGen Corporation, a Delaware corporation (the "Company"),
Gregory T. Went, Ph.D. ("Dr. Went"), the Gregory T. Went 1997 Irrevocable Trust
and the Gregory and Marjorie Went 1997 Children's Trust (collectively, the
"Trusts").

     WHEREAS, the parties wish to provide for Dr. Went's separation from the
Company as an Executive Vice President and for his resignation as a Director of
the Company upon the terms and conditions hereinafter set forth.

     NOW, THEREFORE, in consideration of the foregoing and the mutual agreements
hereinafter set forth, the parties, intending to be legally bound, hereby agree
as follows:

     1.   Employment/Consulting Status: Salary and Benefits. (a) On January 4,
          ----------------------------      
1999, the Company shall make a one-time severance payment to Dr. Went amounting
to $100,000.00, less all normal payroll deductions and withholdings.

     (b)  For the period of time from the date hereof through March 31, 1999
(the "Termination Date"), Dr. Went shall continue as a full-time employee of the
Company. As and when reasonably requested, until the Termination Date, Dr. Went
will assist the Company on strategic alliances and other special projects and
will aid in the transition of his responsibilities. From the date of this
Agreement through December 31, 1998, the Company shall continue to pay Dr. Went
a salary at the rate of $175,000.00 per annum. From January 1, 1999 through the
Termination Date, the Company shall pay Dr. Went a salary at the rate of
$200,000.00 per annum. The salary to be paid to Dr. Went in this Section 1(b)
shall be payable on a periodic basis consistent with past practices and
regardless of whether Dr. Went's employment is terminated for any reason.

     (c)  For the period of time from April 1, 1999 through December 31, 1999,
Dr. Went shall serve as a consultant to the Company. After December 31, 1999,
the term of the consulting period may be extended on a month-to-month basis
until June 30, 2000, if at the beginning of each month Dr. Went has not become
employed on a substantially full-time basis by a subsequent employer, as defined
below. Dr. Went shall notify the Company in writing immediately upon becoming
employed on a full-time basis by a subsequent employer. Dr. Went shall be deemed
to be employed on substantially a full-time basis by a subsequent employer if he
becomes an employee of any one or more entities, or a consultant to any one or
more entities, where such employment and/or consulting together involve (i)
thirty (30) or more hours per week on average or (ii) compensation that would
exceed, when annualized, $150,000.00 per annum. The date on which Dr. Went's
service as a consultant is terminated hereunder is referred to herein as the
"Consulting Termination Date." As and when requested and as mutually agreed,
until the Consulting Termination Date, Dr. Went will assist the Company on
strategic alliances and other special projects, provided, however, that such
services shall require no more than an aggregate of fifteen (15) days (each day
consisting of eight-hours) from April 1, 1999 through December 31, 1999,
provided that Dr. Went shall be available on a $2,000.00 per diem (plus

                                       1
<PAGE>
 
reasonable expenses) basis thereafter, as mutually agreed. During the consulting
period, the Company shall pay Dr. Went a consulting fee at the rate of
$200,000.00 per annum. The consulting fee provided for in this Section 1(c)
shall be paid in equal installments on a periodic basis consistent with the
Company's payroll practices for all salaried employees and regardless of whether
the Company terminates Dr. Went's consulting arrangements for any reason. Dr.
Went shall be promptly reimbursed for all reasonable expenses incurred by him in
connection with the services rendered pursuant to Sections 1(b) and (c) upon
presentation of receipts evidencing such expenses, provided that any expenses in
excess of $500.00 shall receive the prior written approval of the Company. Dr.
Went's services as a consultant shall be performed as an independent contractor
and not as an employee. In accordance therewith, he shall have no authority to
bind, represent or act on behalf of the Company, shall not be an employee for
purposes of any Company benefit, benefit plan, or employment policy and shall
obtain and/or pay for all insurance, taxes and other things required by law and
necessary to the performance of the consulting services, including without
limitation, payment of all local, state and federal employment taxes and
unemployment insurance. The Company shall promptly issue Dr. Went a Form 1099
with respect to the payments for the consulting services.

     (d)  For the period of time from the date hereof through the Termination
Date, the Company shall provide Dr. Went and his eligible dependents with
continued coverage under all health, dental, medical and hospitalization plans
maintained by the Company during such time period on the same terms and
conditions applicable to executive officers of the Company. After the
Termination Date, the Company shall provide Dr. Went with the opportunity to
continue applicable coverages under the Consolidated Omnibus Budget
Reconciliation Act of 1985 ("COBRA"). During the time that Dr. Went is a
consultant to the Company pursuant to this Agreement, the Company, on the
submission of documentation reasonably satisfactory to it, shall reimburse Dr.
Went for his payments under COBRA in the same percentage as it contributed to
such coverage prior to the Termination Date, provided, however, that the
Company's obligation to make such reimbursement shall cease at the earlier of
the expiration of the COBRA coverage period, the Consulting Termination Date, or
such time as Dr. Went becomes eligible for coverage under another employer's
group insurance plan, and provided further that Dr. Went shall notify the
Company in writing immediately upon learning of such eligibility. Until the
Consulting Termination Date, the Company also shall provide Dr. Went with
reasonable email and phone mail access and, until the Termination Date, the
Company shall provide Dr. Went with secretarial support, all as mutually agreed
and consistent with Company policy and practices for employees.

     (e)  The Company hereby assigns and transfers to Dr. Went all of its right,
title and interest in and to the fax machine, personal computers, software
(excluding any information stored thereon which belongs to the Company), and
printer that were installed by the Company at Dr. Went's residence for his use
on behalf of the Company, free and clear of all liens and encumbrances. The
foregoing assets are assigned and transferred to Dr. Went as they exist on the
date hereof and the Company makes no representations or warranties whatsoever
regarding such assets.

     2.   Resignation.  Dr. Went hereby resigns as an officer and director of
          -----------
the Company and as an officer and director of any subsidiaries or affiliates of
the Company, effective on

                                       2
<PAGE>
 
December 31, 1998. After such date, Dr. Went shall have no authority to
represent himself as an officer or director of the Company to any person or
entity or to act or purport to act in any such capacity, but Dr. Went shall
continue as a full-time employee of the Company as described in Section 1 above.

     3.   $250,000.00 Loan. From time to time during the period from April 1,
          ----------------
1999 through March 31, 2001, the Company will make available to Dr. Went a loan
in the maximum principal amount of up to $250,000.00, provided that Dr. Went
must borrow funds under such loan in increments of at least $50,000.00. The loan
will have a term of two years and will bear interest at a variable rate equal to
the prime rate as reported in The Wall Street Journal from time to time,
adjusted monthly. The Company's obligation to extend the loan to Dr. Went is
conditioned upon Dr. Went executing a promissory note in the form attached
hereto as Exhibit A at the time of the first loan.
          ---------

     4.   Stock Options. (a) On the date hereof, the Company shall issue to Dr.
          -------------
Went a stock option exercisable for 25,000 shares of common stock of the Company
(the "Common Stock"), at an exercise price per share equal to the fair market
value of the Common Stock on the date hereof, determined in accordance with the
Company's 1997 Employee, Director and Consultant Stock Option Plan. The option
shall become fully vested and immediately exercisable for all of the Common
Stock thereunder on June 30, 2000 and shall terminate on June 30, 2002. On the
date hereof, the Company shall execute and deliver a stock option agreement, in
the form of Exhibit B attached hereto, evidencing the issuance of the foregoing
            ---------
option.

     (b)  On January 4, 1999, or as soon thereafter as practicable, but in no
event after January 10, 1999, Dr. Went and/or the Trusts shall be allowed to
immediately exercise in full the option to purchase 83,000 shares of Common
Stock under the Non-Qualified Stock Option Agreement between the Company and Dr.
Went, dated December 28, 1993 (the "1993 Stock Option"). In addition, the
Company shall pay to such optionees $83,000.00 to enable them to exercise such
options. Accordingly, at the time of exercise, the $83,000.00 payment will be
deemed to have been received from the Company and, immediately thereafter, to
have been paid to the Company in order to exercise the 1993 Stock Option. Within
three days of such exercise, the Company shall issue to Dr. Went and/or the
Trusts an aggregate of 83,000 shares of Common Stock. The Company shall make an
additional payment (the "Gross-Up Payment") in an amount equal to the sum of (i)
the federal and state income tax liability imposed on receipt of the $83,000.00
payment and the exercise of the 1993 Stock Options, and (ii) the federal and
state income tax liability imposed on receipt of the Gross-Up Payment. The 
Gross-Up Payment shall be calculated assuming that Dr. Went is taxable at the
combined federal and state income tax rate of 45.0%. The Company shall pay any
withholding taxes imposed on any such payments as required and shall treat such
paid withholding taxes as an interest-free advance to Dr. Went, to be recovered
from the Gross-Up Payment. The Gross-Up Payment shall be paid not later than
December 31, 1999. An example of the calculation of the Gross-Up Payment is set
forth on Exhibit C hereof.
         ---------

     (c)  Exhibit D attached hereto sets forth certain information regarding
          ---------
all other options to purchase Common Stock currently held by Dr. Went. Such
options shall remain in effect

                                       3
<PAGE>
 
and shall vest and be exercisable in accordance with the terms thereof. No
amendment, modification or revision of any option agreement listed on Exhibit D,
                                                                      ---------
or the option agreements described in Sections 4(a) and (b) above, shall be
effective unless approved in writing by Dr. Went. The Company represents to Dr.
Went and the Trusts that none of the Common Stock underlying such stock options
is or will be subject to repurchase by the Company.

     (d)  If the Company believes that Dr. Went has engaged in activities
that constitute "cause" under the Stock Options, as defined in Section 5 below,
such that the Company is entitled to terminate Dr. Went's right to exercise the
Stock Options, then the Company shall give Dr. Went fifteen (15) days advance
written notice of its intention to request that the Compensation Committee of
the Board of Directors terminate the Stock Options and provide Dr. Went with an
opportunity to be heard before the Compensation Committee of the Board of
Directors at a time to be mutually agreed upon between the Compensation
Committee and Dr. Went during such fifteen-day period. No such determination of
cause shall be made prior to the end of such fifteen (15) day period.

     5.   Participation in Cashless Exercise Program. As long as Dr. Went
          ------------------------------------------
holds any of the options listed or described in Section 4 above (the "Stock
Options"), Dr. Went shall be entitled to participate, to the same extent as
employees of the Company, in the "cashless exercise" program relating to Company
stock options maintained on the Company's behalf by Morgan Stanley & Co.
Incorporated (or any successor program).

     6.   Lockup and Compliance with Company Trading Policy. (a) Until June 30,
          -------------------------------------------------
1999, each of Dr. Went and the Trusts will not (i) offer, pledge, sell, contract
to sell, sell any option or contract to purchase, purchase any option or
contract to sell, grant any option, right or warrant to purchase, lend, or
otherwise transfer or dispose of, directly or indirectly, any shares of Common
Stock or any securities convertible into or exercisable or exchangeable for
Common Stock, or (ii) enter into any swap or other arrangement that transfers to
another, in whole or in part, any of the economic consequences of ownership of
the Common Stock, whether any such transaction described in clause (i) or (ii)
above is to be settled by delivery of Common Stock or such other securities, in
cash or otherwise. Notwithstanding the foregoing, Dr. Went (but not the Trusts)
may sell or transfer up to 5,000 shares of Common Stock per month beginning
February 1, 1999 .

     (b)  Until the Consulting Termination Date, each of Dr. Went and the Trusts
shall comply with the Company's "Statement of Company Policy-Securities Trades
by Company Personnel," a copy of which is attached hereto as Exhibit E. The
                                                             ---------
Company represents that (i) all of the Stock Options have been granted in
accordance with Rule 16b-3 of the Securities and Exchange Act of 1934, as
amended (the "34 Act"), (ii) except for the Common Stock underlying the Stock
Options held by the Trusts, the Common Stock underlying the Stock Options has
been registered on Form S-8's under the Securities Act of 1933, as amended,
(iii) upon Dr. Went's exercise of any of the Stock Options held by him, it will
cause its legal counsel to promptly issue any necessary instructions to the
Company's transfer agent so that Dr. Went may readily resell or transfer the
shares obtained upon exercise of any of the Stock Options, and (iv) upon the
Trusts' exercise of any of the Stock Options held by them, it will cause its
legal counsel to promptly

                                       4
<PAGE>
 
issue any necessary instructions to the Company's transfer agent so that such
shares will be issued with the appropriate restrictive legends.

     7.   Return of Property. Within ten days of the date of this Agreement,
          ------------------
Dr. Went shall return to the Company all property, except as set forth herein or
in writing from the Chief Executive Officer or the Chief Financial Officer of
the Company, that belongs to the Company or that otherwise pertains to its
business, including, without limitation, any and all documents and copies
thereof, compilations of information in any form, software and credit cards. On
or prior to the Termination Date, Dr. Went shall return to the Company all keys,
security access cards, identification cards and other means of obtaining access
to its premises.

     8.   Non-Disparagement.  (a) For a period of five years from the date
          -----------------
hereof, Dr. Went will not make any statements that are professionally
disparaging about, or adverse to, the interests of the Company (including its
officers, directors and employees), including, but not limited to, any
statements that disparage any person, product, service, finances, financial
condition, capability or any other aspect of the business of the Company, and
Dr. Went will not engage in any conduct that is intended to harm professionally
or personally the reputation of the Company, including its officers, directors
and employees.

     (b)  For a period of five years from the date hereof, the Company will
cause its officers, directors and human resources personnel not to make any
statements that are professionally or personally disparaging about, or adverse
to, the interests of Dr. Went, and not to engage in any conduct that is intended
to harm professionally or personally the reputation of Dr. Went.

     (c)  Attached hereto as Exhibit F is the Company's press release announcing
                             ---------   
Dr. Went's departure. For a period of five years from the date hereof, neither
Dr. Went nor the Company will make any statement relating to Dr. Went's
departure that is inconsistent with such press release.

     (d)  In the event that Dr. Went violates this Section 8, such violation
will not constitute "cause" under the Stock Options or result in the termination
of his right to exercise the Stock Options.

     9.   Employee Confidential Information and Inventions Agreement.
          ----------------------------------------------------------
Notwithstanding any other provision of this Agreement, the Employee Confidential
Information and Inventions Agreement, attached hereto as Exhibit G, shall
                                                         ---------
survive the execution of this Agreement and shall remain in effect in accordance
with its terms, provided, however, that the period described in paragraph 6(a)
of such agreement shall extend to and until December 31, 1999 or the maximum
period permitted by applicable law (whichever is shorter).

     10.  Non Solicitation and Hiring. Until December 31, 1999, Dr. Went, either
          ---------------------------
individually or on behalf of or through any third party, shall not directly or
indirectly (i) solicit, entice or persuade or attempt to solicit, entice or
persuade any employees of or consultants to the Company or to any present or
future parent, subsidiary or affiliate of the Company to leave the

                                       5
<PAGE>
 
services of the Company or of any such parent, subsidiary or affiliate for any
reason, or (ii) hire, as a consultant or employee, any person who was an
employee or consultant of the Company at any time during the six months prior to
his or her date of hire by Dr. Went, either individually or on behalf of or
through any third party.

     11.  Cooperation. In connection with the services described in Section 1,
          -----------
Dr. Went shall cooperate fully with the Company in the defense or prosecution of
any patent applications or patents of the Company and any claims or actions now
in existence or which may be brought or threatened in the future against or on
behalf of the Company, including any claims or actions against its officers,
directors and employees, except that after the termination of Dr. Went's
employment and service as a consultant under Section 1 hereof, Dr. Went's
cooperation under this paragraph shall be at the parties' mutual convenience and
agreement and Dr. Went shall be entitled to receive the per diem amount
specified in Section 1(c) hereof. Dr. Went's cooperation in connection with such
actions or claims shall include, without limitation, his being available to meet
with the Company in connection with any contract matters or audits, to prepare
for any proceeding (including, without limitation, depositions, consultation,
discovery or trial), to provide affidavits, to assist with any audit,
inspection, proceeding or other inquiry, or to act as a witness in connection
with any litigation or other legal proceeding affecting the Company. Dr. Went
further agrees that should he be contacted (directly or indirectly) by any party
representing an individual or entity adverse to the Company, he shall promptly
notify the Company.

     12.  Release and Waiver. (a) Dr. Went hereby agrees and acknowledges that
          ------------------
by signing this Agreement and accepting the payments and benefits to be provided
to him, and other good and valuable consideration provided for in this
Agreement, he is waiving his right to assert any form of legal claim against the
Company1 whatsoever for any alleged action, inaction or circumstance existing or
arising from the beginning of time through the Termination Date. Dr. Went's
waiver and release herein is intended to bar any form of legal claim, charge,
complaint or any other form of action (jointly referred to as "Claims") against
the Company seeking any form of relief including, without limitation, equitable
relief (whether declaratory, injunctive or otherwise), the recovery of any
damages or any other form of monetary recovery whatsoever (including, without
limitation, back pay, front pay, compensatory damages, emotional distress
damages, punitive damages, attorneys fees and any other costs) against the
Company, for any alleged action, inaction or circumstance existing or arising
through the Termination Date.

     Without limiting the foregoing general waiver and release, Dr. Went
specifically waives and releases the Company from any Claim arising from or
related to his employment relationship with the Company or the termination
thereof, including, without limitation:

     (i)  Claims under any state or federal discrimination, fair employment
          practices or other employment related statute, regulation or executive
          order (as they may have been amended through the Termination Date)
          prohibiting discrimination or harassment based upon any protected
          status including, without limitation, race, national origin, age,
          gender, marital status, disability, veteran status or sexual

--------
1 For the purposes of this Section 12, the parties agree that the term "Company"
shall include Company, its divisions,  affiliates and subsidiaries,  and its and
their respective officers, directors, employees, agents and assigns.

                                       6
<PAGE>
 
          orientation. Without limitation, specifically included in this
          paragraph are any Claims arising under the federal Age Discrimination
          in Employment Act, the Older Workers Benefit Protection Act, the Civil
          Rights Acts of 1866 and 1871, Title VII of the Civil Rights Act of
          1964, the Civil Rights Act of 1991, the Equal Pay Act, the Americans
          With Disabilities Act and any similar Connecticut or other state
          statute.

     (ii) Claims under any other state or federal employment related statute,
          regulation or executive order (as they may have been amended through
          the Termination Date) relating to wages, hours or any other terms and
          conditions of employment. Without limitation, specifically included in
          this paragraph are any Claims arising under the Fair Labor Standards
          Act, the Family and Medical Leave Act of 1993, the National Labor
          Relations Act, the Employee Retirement Income Security Act of 1974,
          COBRA and any similar Connecticut or other state statute.

     (iii)Claims under any state or federal common law theory including, without
          limitation, wrongful discharge, breach of express or implied contract,
          promissory estoppel, unjust enrichment, breach of a covenant of good
          faith and fair dealing, violation of public policy, defamation,
          interference with contractual relations, intentional or negligent
          infliction of emotional distress, invasion of privacy,
          misrepresentation, deceit, fraud or negligence.

     (iv) Any other Claim arising under local, state or federal law.

          Notwithstanding the foregoing, this Section 12 does not release the
Company, and Dr. Went expressly reserves claims arising from any obligation
contained in this Agreement. Dr. Went acknowledges and agrees that, but for
providing this waiver and release, he would not be receiving the payments and
benefits being provided to him under the terms of this Agreement.

          (b)    The Company releases and discharges Dr. Went from any and all
actions, causes of action, suits, debts, dues, sums of money, accounts,
covenants, contracts, controversies, agreements, promises, judgments, demands,
liability, claims and damages whatsoever, in law or equity, that the Company
ever had or now has, including without limitation, any claim arising from or
relating to Dr. Went's employment with, service as an officer and director of,
or direct or indirect holding of equity securities in, or in any other capacity
relating to the Company, including, but not limited to, any claims arising under
any federal, state or local law or ordinance, tort, employment contract (express
or implied), public policy, or any other obligation, other than those relating
to the performance of Dr. Went's obligations under this Agreement.

          (c)    Nothing herein shall alter, amend or modify the Company's
obligations to indemnify Dr. Went in connection with any action or omission
while Dr. Went was a director and officer of the Company. The Company shall at
all times provide Dr. Went the same amount of coverage and he shall be entitled
to the same level (and no lesser level) of indemnification as any other officer
or director of the Company pursuant to any charter, by-law, director and officer
liability policy or other agreement.

                                       7
<PAGE>
 
     13.  Representations and Warranties. (a) The Company represents and
          ------------------------------
warrants to Dr. Went and the Trusts as follows: (i) that it has full legal
right, power and authority to enter into and perform all of its obligations
under this Agreement and to perform the actions to be performed by it pursuant
to this Agreement; (ii) the execution and delivery of this Agreement by it will
not violate any other agreement to which it is a party, (iii) no consent of any
third party is required for the execution and performance of this Agreement by
it, and (iv) this Agreement has been duly executed and delivered by it and
constitutes its legal, valid and binding agreement enforceable in accordance
with its terms, subject to bankruptcy, insolvency, fraudulent conveyance,
reorganization, moratorium and similar laws, now or hereafter in effect,
affecting creditors' rights and remedies generally and to general principles of
equity.

     (b)  Each of Dr. Went and the Trusts represents and warrants to the Company
as follows: (i) that he or it has full legal right, power and authority to enter
into and perform all of its obligations under this Agreement and to perform the
actions to be performed by it pursuant to this Agreement; (ii) the execution and
delivery of this Agreement by him or it will not violate any other agreement to
which he or it is a party, (iii) no consent of any third party is required for
the execution and performance of this Agreement by him or it, and (iv) this
Agreement has been duly executed and delivered by him and it and constitutes his
and its legal, valid and binding agreement enforceable in accordance with its
terms, subject to bankruptcy, insolvency, fraudulent conveyance, reorganization,
moratorium and similar laws, now or hereafter in effect, affecting creditors'
rights and remedies generally and to general principles of equity. Dr. Went
further represents that since June 30, 1998, he has not had any "reportable
transactions" under Section 16(a) of the 34 Act, other than the grant of the
Stock Options.

     14.  Equitable Relief. Dr. Went hereby expressly covenants and agrees that
          ----------------
the Company will suffer irreparable damage in the event any of the provisions of
Section 9, 10 and 11 hereof, including the provisions of the Employee
Confidential Information and Inventions Agreement referred to therein, are not
performed or are otherwise breached and that the Company shall be entitled as a
matter of right (without the need to prove actual damages) to an injunction or
injunctions and other relief to prevent a breach or violation by Dr. Went and to
secure the enforcement of such provisions. Resort to such equitable relief,
however, shall not constitute a waiver of any other rights or remedies which the
Company may have.

     The Company hereby expressly covenants and agrees that Dr. Went will suffer
irreparable damage in the event any of the provisions of this Agreement are not
performed or are otherwise breached and that Dr. Went shall be entitled as a
matter of right (without the need to prove actual damages) to an injunction or
injunctions and other relief to prevent a breach or violation by the Company and
to secure the enforcement of such provisions. Resort to such equitable relief,
however, shall not constitute a waiver of any other rights or remedies which Dr.
Went may have.

     15.  Confidentiality. All information relating in any way to the subject
          ---------------
matter of this Agreement, including the terms and amount of payments and
benefits provided under this Agreement, shall be held confidential by the
Company and Dr. Went and shall not be publicized or disclosed to any person
(other than an immediate family member, legal counsel or financial

                                       8
<PAGE>
 
advisor, provided that any such individual to whom disclosure is made agrees to
be bound by these confidentiality obligations), business entity or government
agency (except where disclosure is mandated by state or federal law or
regulation or by legal process).

     16.  Notice. All notices, requests and other communications to any party
          ------
hereunder shall be given or made in writing and mailed (by registered or
certified mail or by overnight courier) or delivered by hand as follows:

          (a)    if to the Company, to it at:

                 CuraGen Corporation
                 Long Wharf Maritime Center
                 555 Long Wharf Drive, 11th Floor
                 New Haven, Connecticut 06511
                 Attention:       Jonathan M. Rothberg, Chief Executive Officer

          with a copy to:

                 Mintz, Levin, Cohn, Ferris, Glovsky
                   and Popeo, P.C.
                 One Financial Center
                 Boston, MA 02111
                 Attention:       Jeffrey M. Wiesen, Esquire

          (b)    if to Dr. Went or the Trusts at:

                 Gregory T. Went, Ph.D.
                 34 Scotland Avenue
                 Madison, CT  06443

          with a copy to:

                 Gadsby and Hannah LLP
                 225 Franklin Street
                 Boston, MA 02110
                 Attention:       Lawrence Gennari, Esquire

or such address as such party may hereafter specify for the purpose of notice to
the other party hereto. Each such notice, request or other communication shall
be effective when, if delivered by hand, received by the party to which it is
addressed or, if mailed in the manner described above, on the third business day
after the date of mailing.

     17.  Successors and Assigns.  The rights and obligations of the Company
          ----------------------
under this Agreement shall inure to the benefit and be binding upon its
successors and assigns and any entity to which its assets and business may be
transferred by operation of law or otherwise. This 

                                       9
<PAGE>
 
Agreement is personal to Dr. Went and the Trusts and they shall not, without the
written consent of the Company, assign their rights or obligations hereunder,
other than by will or the laws of descent and distribution, but the provisions
hereof shall inure to the benefit of and be enforceable by Dr. Went's heirs and
legal representatives.

     18.  Arbitration. Except with respect to proceedings to obtain equitable
          -----------
relief as provided in Section 14 hereof, any dispute, controversy, or claim
arising out of, in connection with, or in relation to this Agreement and its
exhibits, shall be settled by arbitration in Hartford, Connecticut, or such
other place as agreed by the parties, pursuant to the Commercial Rules then in
effect of the American Arbitration Association. Notwithstanding anything else
contained herein, the arbitration shall be before one arbitrator who, within ten
(10) days of the receipt by one party of a Demand for Arbitration by the other
party, shall be selected by agreement of the parties. Failing such agreement,
the parties, within five (5) days thereof, shall submit the matter to the
American Arbitration Association and the arbitrator shall be selected and
appointed by the American Arbitration Association itself. The arbitrator's
decision shall be rendered within sixty (60) days of his/her selection and shall
be in writing with a statement of the reasons supporting such decision. Any
award or determination shall be final, binding, and conclusive upon the parties,
except as provided by the applicable arbitration statute, and judgment rendered
may be entered thereon in any court having jurisdiction thereof. Dr. Went and
the Company knowingly waive any and all rights to jury trial in any forum. The
parties hereby expressly waive punitive damages. Each party shall bear its own
expenses, including attorney's fees, relating to the arbitration unless
otherwise determined in the arbitration.

     19.  Dr. Went's Expenses. Within three business days of the execution of
          -------------------
this Agreement, the Company shall pay all of the expenses incurred by Dr. Went
in connection with this Agreement, including legal and accounting fees, not to
exceed $10,000.00.

     20.  Governing Law. This Agreement shall be construed in accordance with
          -------------
and governed by the substantive laws of the State of Delaware, without regard to
the choice of law rules thereof.

     21.  Complete  Understanding.  Except as expressly provided herein, this
          -----------------------  
Agreement supersedes any prior contracts, understandings, discussions and
agreements among the parties and constitutes the complete understanding between
them with respect to the subject matter hereof. No statement, representation,
warranty or covenant has been made by any party with respect hereto except as
expressly set forth therein.

     22.  Modification: Waiver. (a) This Agreement may be amended or waived if,
          --------------------
and only if, such amendment or waiver is in writing and signed, in the case of
an amendment, by the Company on the one hand and Dr. Went and the Trusts on the
other or in the case of a waiver, by the party against whom the waiver is to be
effective.

     (b)  No failure or delay by any party in exercising any right, power or
privilege hereunder shall operate as a waiver thereof nor shall any single or
partial exercise thereof preclude any other or further exercise thereof or the
exercise of any other right, power or

                                       10
<PAGE>
 
privilege. The rights and remedies herein provided shall be cumulative and shall
not be exclusive of any rights or remedies provided by law or at equity.

     23.  Headings. The section headings in this Agreement are for convenience
          --------
of reference only and shall not control or affect the meaning or construction of
this Agreement.

     24.  Counterparts. This Agreement may be signed in any number of
          ------------
counterparts, each of which shall be an original, with the same effect as if the
signatures thereto and hereto were upon the same instrument. This Agreement
shall become effective when each party hereto shall have received counterparts
hereof signed by the other party hereto.

     25.  Construction.  Dr. Went, the Trusts and the Company have cooperated in
          ------------
the drafting and preparation of this Agreement. Hence, in any construction to be
made of this Agreement, the same shall not be construed against any party on the
basis that the party was the drafter.

     26.  Further Assurances. The parties hereto shall, at the request of any
          ------------------
other party, execute and deliver any further instruments or documents and take
all such further action as such party reasonably may request in order to
consummate and make effective the foregoing provisions of this Agreement.

                                       11
<PAGE>
 
     IN WITNESS WHEREOF, the Company and the Trusts have caused this Agreement
to be duly executed in its name by one of its duly authorized representative,
and Dr. Went has manually signed his name hereto, as of the date first written
above.


                                      /s/ Gregory T. Went, Ph.D.
                                      --------------------------  
                                      Gregory T. Went, Ph.D.


                                      GREGORY T. WENT 1997
                                      IRREVOCABLE TRUST


                                      By: /s/ James M. Bustillo
                                          ---------------------

                                      By: /s/ Marjorie Went
                                          -----------------

                                          Its Trustees


                                      GREGORY AND MARJORIE WENT
                                      1997 CHILDREN'S TRUST


                                      By: /s/ James M. Bustillo
                                          ---------------------

                                      By: /s/ Marjorie Went
                                          -----------------

                                          Its Trustees


                                      CURAGEN CORPORATION


                                      By /s/ David M. Wurzer
                                         -------------------
                                          Its /s/ EVP and CFO
                                              ---------------

                                       12