Document:

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                                                                   EXHIBIT 10.16

                                     NASHUA

                            MANAGEMENT INCENTIVE PLAN

                                  PLAN DOCUMENT

                                                                      MARCH 1999

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

PURPOSE

The purpose of Nashua Corporation's Management Incentive Plan ("Plan") is:

1. To link senior management cash compensation to the financial performance of
   the organization.

2. To motivate and reinforce the following behaviors among senior managers:

     * Effective goal-setting tied to key strategic priorities,
     * Accountability for goal achievement.

3.   To provide a means for making awards that qualify for the performance-based
     compensation exception described at Section 162(m) of the Internal Revenue
     Code (the "Code").

PLAN OPERATION

The Management Incentive Plan provides cash incentive payments based upon
achievement of corporate and/or divisional financial performance goals and
achievement of personal goals by Plan Participants, as described below.

1.   Salary Administration

     For positions covered by the Management Incentive Plan, salary levels are
     established such that, when combined with target incentive opportunities
     (expressed as a percent of base salary), target total cash compensation is
     both competitive with comparable companies and equitable within the
     internal organization.

     The following definitions apply:

     BASE SALARY                        The annualized regular cash compensation
                                        of a Participant, excluding incentive
                                        payments, company contributions to
                                        employee benefit plans, relocation, or
                                        other compensation not designated as
                                        salary. The base salary is the basis for
                                        regular paychecks.

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

1.   Salary Administration (continued)

     TARGET INCENTIVE                   That amount (described as a percentage
                                        of a Participant's base salary) that
                                        will be paid as an incentive if the
                                        target financial performance goals and
                                        personal goals are fully (100%)
                                        achieved.

     TARGET TOTAL CASH COMPENSATION     The assigned compensation level for each
                                        Participant, based on market data and
                                        internal equity considerations.
                                        Comprised of base salary and target
                                        incentive amount.

     Target Incentive opportunities range from 10% to 50% of base salary for
     Participants depending, in part, upon the management level and unit size of
     the participants.

2.   Weighting of Goals

     Each year specific weighting among corporate and division financial
objectives and strategic and personal objectives will be established based on
the business objectives for the year.

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

3.   Financial Performance Goals

     Prior to the beginning of the Plan Year, financial performance goals are
     developed by Senior Management and reviewed by the Compensation and
     Leadership Committee of the Board of Directors. Financial performance may
     be defined using any of the standard financial metrics (e.g., Sales,
     Income, Cash Flow), and will be determined each year. Two levels of
     financial performance are defined each year, as follows:

     TARGET           The budgeted financial goal which represents a
                      realistically attainable level of corporate or divisional
                      financial performance for the year.

     THRESHOLD        A level of achievement against the budgeted financial
                      goal, set below target and representing the minimum level
                      of performance which is required in order to pay the
                      financial-based portion of an employee's incentive.

4.   Personal Goals

     Each Plan participant is assigned a limited number (i.e., 2 - 3) of
     objective pre-established Personal Goals which are typically based upon the
     strategic plans for the business. These personal goals are compensable
     under the Plan.

     As with financial performance goals, a threshold level of personal goal
     achievement is established each year, below which no payout for each
     personal objective will be made. For example, if the threshold for a
     manager's personal objective achievement is 80%, the manager will receive
     no payout related to that goal if she achieves only 50% of that objective.

5.   Plan Funding

     The budgeted incentive pool equals the sum of the Target Incentives of all
     eligible Participants company-wide. The pool is funded each year depending
     upon the financial and personal goal performance of the Plan participants,
     and upon the threshold levels set for that year.

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

6.   Distributions to Participants

     The component of incentive payment tied to financial goals is paid out in
     direct relationship to the financial performance if the business unit
     achieves its threshold. Payout for above-target financial performance is
     not capped.

     The personal goals payout component is paid in relation to the proportion
     of personal goal achievement if the Participant's actual results for the
     plan year meet the personal goal threshold. The payout for the personal
     goals component of the incentive is capped at 100%.

     Incentive payout examples:

--------------------------------------------------------------------------------
DIVISION MANAGEMENT INCENTIVE PAYMENT:

                           --------------------------
                           Target Incentive = $20,000
                           --------------------------
                                        |
                                        V
    Financial Goal Component 60%           Strategic/Personal Goal Component 40%
                     --------------------------------------
                     |                                    |
                     V                                    V
       ---------------------                      --------------------
       20,000 x 60% = 12,000                      20,000 x 40% = 8,000
       ---------------------                      --------------------

    Division financial results                   Strategic/Personal Goal
       were 105% of Target                         Achievement was 95%
       ----------------------                     -------------------
       12,000 x 105% = 12,600                     8,000 x 95% = 7,600
       ----------------------                     -------------------
                     |                                    |
                     V                                    V
                     --------------------------------------
                                        |
                                        V
                           --------------------------
                             Total Incentive Payout
                           $12,600 + $7,600 = $20,200
                           --------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
CORPORATE STAFF INCENTIVE PAYMENT:

                           --------------------------
                           Target Incentive = $20,000
                           --------------------------
                                        |
                                        V
    Financial Goal Component 80%           Strategic/Personal Goal Component 20%
                     --------------------------------------
                     |                                    |
                     V                                    V
       ---------------------        This example      --------------------
       20,000 x 80% = 16,000     assumes corporate    20,000 x 20% = 4,000
       ---------------------         financial        --------------------
                                  performance is
    Corporate financial results   below threshold,   Strategic/Personal Goal
        were 87% of Target        but the manager     Achievement was 90%
    ----------------------------  achieves above-     -------------------
    No payout for this component  threshold personal  4,000 x 90% = 3,600
    ----------------------------  goal performance.   -------------------
                     |                                    |
                     V                                    V
                     --------------------------------------
                                        |
                                        V
                           --------------------------
                             Total Incentive Payout
                              $0 + $3,600 = $3,600
                           --------------------------

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

     7.  Timing

     Payments from the Plan will be made as soon as practicable after the end of
     the Plan Year, but no later than April 1 of the following year. Incentive
     payments are made in a single lump-sum payment and are subject to
     applicable withholding and other taxes as prescribed by local law.

PARTICIPATION

Plan Participants are senior managers and other key employees whose
responsibilities and accomplishments can be directly tied to significant
short-term business goals.

In order to be eligible for an incentive payment, a participant must have been
employed in a Plan-eligible position(s) for at least six consecutive months of
the Plan Year. For a participant who serves in a Plan-eligible position(s) for
less than a full year, the incentive payment may be pro-rated based on the
number of months, including partial months, the individual was a participant
during the Plan Year.

In all cases, the Incentive Compensation Committee (the CEO, the Chief Financial
Officer, and the Vice President of Human Resources) reserves the authority to
exercise its discretion in determining incentive payments. However, the
following guidelines have been provided as a starting point for making decisions
regarding incentive eligibility in cases of new hires, employment terminations,
periods of disability or leave, and transfers into, out of, and between
Plan-eligible positions during the Plan Year.

1.   New Hires and Transfers into Eligible Positions when Employee Serves at
     Least Six Consecutive Months in the Position

     A non-participant hired, transferred, promoted, or re-assigned into an
     eligible position during the Plan Year will be considered for an Incentive
     Payment on a pro-rated basis, provided that the employee is employed for at
     least six consecutive months of the Plan Year.

2.   New Hires into Eligible Positions when Employee Serves Less Than Six
     Consecutive Months in the Position

     When offers are made to candidates for Plan-eligible positions, and the
     employee will serve in the position for less than six consecutive months in
     the current Plan Year, the offer may include a guaranteed cash compensation

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

     amount in addition to the base salary, to compensate for the missed
     opportunity in the first (partial) year. This amount should be no more than
     the target incentive for which the employee would have been eligible in
     that year, pro-rated by the number of months employed; and is to be paid at
     the same time incentives are paid in the following year. The employee will
     be integrated into the Plan in the full Plan Year following his/her hire
     date.

3.   Transfers into Ineligible Positions

     An employee transferred from an eligible position into a non-eligible
     position may be considered for a pro-rated incentive payment, provided that
     the employee has served at least six months in an eligible position(s)
     during the Plan Year. Any incentive payment will be based on the base
     salary while the employee was a Plan participant.

     In these cases, an adjustment to base salary may be required in order to
     achieve the appropriate salary level for the new (non-Plan) position. (For
     example, the base salary may be increased to reach a reasonable
     market-based pay rate if there is no longer the possibility of an incentive
     payment.) When the adjustment required is a positive one, it may be made
     retroactively in cases where the transfer occurs before the employee
     reaches the six-month minimum service required for an incentive payment.

4.   Transfers from One Plan-Eligible Position to Another

     In the event that a participant transfers from one incentive eligible
     position to another before the completion of the Plan Year, an assessment
     will be made to determine the relative impact of goal achievement in each
     position on the final incentive payment. Typically, the participant will be
     paid a pro-rated share of the incentive payment amount for each position.
     However, the Incentive Compensation Committee has discretion to determine
     otherwise if the duration of service in either of the Plan-eligible
     positions is considered too short a period in which to achieve results
     against the stated goals. In either event, the participant's incentive
     payment will reflect the full twelve months of participation.

     In the case of a current Participant moving from one Target Incentive level
     to another, an adjustment to base salary may be required in order to
     achieve the appropriate Target Total Cash Compensation level.

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

5.   Terminations

     All Incentive Payments under the Plan will be forfeited for participants
     whose employment is terminated for any reason other than normal or early
     retirement under the provisions of the Company's retirement plan, death or
     disability during the Plan Year, unless determined otherwise by the
     Incentive Compensation Committee.

     If a Plan participant is employed on the last day of the Plan Year, but
     terminates employment prior to the date of the incentive payment, the
     Incentive Compensation Committee shall retain discretion over whether a
     payment is made to that participant.

6.   Disability, Leaves of Absence, and Sabbaticals

     Even if an employee meets the requirement of six or more consecutive months
     in a Plan-eligible position, the employee must have rendered services for a
     minimum of three consecutive months in any Plan Year when attendance is
     interrupted by a period of disability, a leave of absence, or a sabbatical
     in order for any incentive to be paid (including that amount based on
     corporate and division/geography results).

     If the employee meets the requirement of three consecutive months of
     rendering services, the incentive payment would typically be pro-rated
     based on the number of months in the Plan Year that the employee was
     present and fully performing the job. Assessment of performance against
     personal goals will be based on the amount of time the employee was
     actually rendering services.

7.   Pro-rating

     For a participant who serves in a Plan-eligible position(s) for less than a
     full year, the pro rata share of the incentive payment shall equal the
     number of months, including partial months, the individual was rendering
     services in a Plan-eligible position during the Plan Year divided by
     twelve, times the Incentive Payment amount (based on results achieved).

EFFECT ON TAXES

Payments made under this Plan will be included in total wages in the year paid,
and are thus considered taxable income in that year.

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

EFFECT ON BENEFITS

Regular Management Incentive Plan payments are included in covered wages for
purposes of the 401(k) and pension plans.

TERMS AND CONDITIONS

1.   The Plan shall be approved by the Board of Directors and administered by
     the Incentive Compensation Committee (the "Committee"). The Committee shall
     have authority, consistent with the Plan, to establish Plan periods during
     which awards may be established and earned under the Plan, to determine the
     size and terms of the awards to be made to each Plan Participant, to
     determine the time when awards will be made, to prescribe the form of
     payment for awards under the Plan, to adopt, amend and rescind rules and
     regulations for the administration of the Plan and for its own acts and
     proceedings, and to decide all questions and settle all controversies and
     disputes which may arise in connection with the Plan. All decisions,
     determinations and interpretations of the Committee shall be binding upon
     all parties concerned.

     The terms of an award, once fixed, shall preclude future Committee
     discretion with respect to the amount or timing of payments of the award,
     except that (i) no payment of an award shall be made unless and until the
     Committee certifies in writing that the performance goals specified in the
     award have been satisfied; (ii) the Committee may retain the discretion to
     reduce payments; (iii) the Committee may permit the deferral of payments
     that have been earned under an award provided such deferral is consistent
     with Section 162 of the Code and (iv) the Committee may retain such other
     discretion as is consistent with the qualification of the award under
     Section 162(m).

2.   Corporate Performance results are determined at the end of the fiscal year
     when audited data is available. Adjustments may be made in order to
     minimize the potential distortion of performance measurements resulting
     from major unplanned/uncontrollable events, such as a major unbudgeted
     acquisition, non-operating gains or losses or extraordinary operating
     items, or other events or conditions during the year affecting financial
     performance, so long as such adjustments are made without the involvement
     of the CEO, and are in conformity with Section 162(m) of the Internal
     Revenue Code. Such adjustments may be made when it is judged that the
     Corporation would have been unable to anticipate said event(s) during the
     corporate goal setting process.

3.   The Management Incentive Plan does not, directly or indirectly, create in
     any employee or class of employees any right with respect to continuation
     of em-

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MANAGEMENT INCENTIVE PLAN                                          PLAN DOCUMENT

     ployment by the Company, and it shall not be deemed to interfere in any way
     with the Company's right to terminate, or otherwise modify, an employee's
     employment at any time. No employee shall have a right to be selected as a
     Participant for any year nor, having been selected a Participant in the
     Plan for one year, to be a Participant in any other year. Neither the Plan
     nor any award thereunder shall be an element of damages in any claim based
     upon discharge in violation of a contract unless the contract in question
     shall be in writing and shall make specific reference to this section and
     this sentence, overriding the same; nor shall this Plan or any rights
     thereto be regarded as an element of damages for wrongful discharge in any
     other context except to the extent that rights shall have accrued hereunder
     as of the date of discharge.

4.   The provisions of the Plan and the grant of any incentive payment shall
     inure to the benefit of all successors of each Participant, including
     without limitation such Participant's estate and the executors,
     administrators or trustees thereof, heirs and legatees, and any receiver,
     trustee in bankruptcy or representative of creditors of such Participant.

5.   The Plan may be amended or terminated at any time, and shall continue in
     effect until so terminated; provided however that no amendment or
     termination of the Plan shall adversely affect any right of any Plan
     Participant with respect to any incentive payment theretofore made without
     such Plan Participant's written consent.

6.   The Plan shall be effective with respect to the Plan Year beginning January
     1, 1998.

7.   This Plan and all determinations made and actions taken hereunder shall be
     construed in accordance with the laws of the State of New Hampshire.

Page 9<PAGE>   1
                                                                   Exhibit 10.28

                                December 1, 1999

Cambridge NeuroScience, Inc.
One Kendall Square, Building 700
Cambridge, MA 02139

         Re:      Collaborative Research, Development and Marketing Agreement
                  dated as November 20, 1996 (the "Agreement")
                  -----------------------------------------------------------

Ladies and Gentlemen:

         This letter is to document our mutual understanding regarding amending
and supplementing the Agreement. Capitalized terms herein shall have the meaning
set forth in the Agreement. In consideration of our mutual obligations in this
Amendment and Supplement Letter, CNSI and Allergan hereby agree as follows:

         1.       EXTENSION OF RESEARCH PHASE. The Research Phase as described
in Section 1.31 of the Agreement shall be amended to have a term of four (4)
years, commencing November 20, 1996, and ending November 20, 2000. The Research
Phase will be subject to earlier termination as provided in the Agreement.
Attached to this Amendment and Supplement Letter as ANNEX A is the current
Research Plan. In consideration of CNSI's performance of its obligations for the
additional year of the Research Phase, Allergan will pay CNSI One Million Two
Hundred Fifty Thousand Dollars ($1,250,000), as supported by a Research Plan and
budget. The amount shall be payable as set forth in Section 9.1.1 of the
Agreement. In the event that Allergan terminates the Agreement pursuant to
Section 14.1 or 14.2, Allergan shall be obligated to pay, the unpaid portion, if
any, of such One Million Two Hundred and Fifty Thousand Dollars ($1,250,000), in
accordance with the payment schedule in Section 9.1.1 of the Agreement.

         2.       CHANGE IN AVAILABILITY PERIOD. Section 5.3 of the Agreement is
amended to change the definition of "Availability Period." From the date hereof,
Availability Period shall mean the period ending on the later of twelve (12)
months following the date of designation of an Active Compound as a
Collaboration Compound or May 20, 2000. In conformity with Section 5.3, CNSI
agrees that it will not grant any license or other rights to a Third Party under
its interest in any Collaboration Compound during the Availability Period. In
addition, the Availability Period may be extended pursuant to Section 5.3.

         3.       EXPANSION OF FIELD. For purposes of the research license in
Section 8.1.1 of the Agreement, the definition of Field shall be expanded to
mean research, development and commercialization activity with respect to
compounds which block one or more than one

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subclass of the glutamate-activated ion channels, including NMDA channels,
and/or one or more subclass of sodium channels, for the treatment of pain, in
addition to ophthalmic disease and disorders, provided however, that such
research license shall be nonexclusive outside the Field as originally defined
in the Agreement. The commercial license for any Development Compound and its
Back-Up Compounds selected by Allergan under Section 5.4, shall be exclusive in
the Field as expanded hereby. However, if Allergan designates a Collaboration
Compound as a Development Compound pursuant to Section 5.4 of the Agreement for
pain, and at that time Allergan has not designated that Collaboration Compound,
or another Collaboration Compound, as a Development Compound for the treatment
of ophthalmic diseases and disorders, then Allergan shall no longer have the
right to select a Development Compound for the treatment of ophthalmic diseases
and disorders.

         4.       MILESTONE PAYMENTS. The milestone payments set forth in
Section 9.4.1 of the Agreement shall be applicable only one time with respect to
each Development Compound (or its Back-Up Compounds) even if Allergan ultimately
reaches one or more of such milestones for more than one indication.

         5.       UPDATED LIST OF EXCLUDED COMPOUNDS. Prior to execution of this
Amendment and Supplement Letter, CNSI shall provide to Allergan an updated list
of Excluded Compounds as described in Section 5.7 of the Agreement. Such updated
list shall be attached to this amendment and supplement letter as ANNEX B.

         6.       PATENT PROSECUTION. The parties agree that, notwithstanding
anything in Section 10.2 of the Agreement to the contrary, patent applications
with respect to Joint Inventions or Joint Patent Rights, which have applications
with respect to a Development Compound whether inside the Field as originally
provided in the Agreement or as expanded under Section 3 of this Amendment and
Supplement Letter, shall be filed by Allergan in such countries as reasonably
determined by Allergan, after consultation with CNSI. Allergan shall consult
with CNSI as to the preparation and filing (if time permits), prosecution and
maintenance of such patent applications and patents, and shall furnish to CNSI
copies of documents relevant to such preparation, filing, prosecution or
maintenance sufficiently prior to filing such document or making any payment due
thereunder to allow for review and comment by CNSI and Allergan shall seriously
consider all such comments. In the event that Allergan does not file, prosecute
and maintain any such patent application or patent as set forth above, it shall
give CNSI forty-five (45) days' notice before any relevant deadline and transmit
all information reasonable and appropriate relating to such patent application
or patent, and CNSI shall have the right to pursue, at its own expense, filing,
prosecution and maintenance thereof, in which event Allergan shall assign all
its rights therein to CNSI.

         7.       UPDATED REPRESENTATIONS AND WARRANTIES. Each party hereby
confirms to the other that as of the date hereof the representations and
warranties of such party in Article 12 of the Agreement are true and correct as
if made on the date hereof.

         8.       MODIFICATION OF TERMINATION PROVISION. Section 14.4.4 of the
Agreement entitled "Failure to Select a Development Compound" is hereby amended
to read "By either Party if Allergan has failed to select a Development Compound
pursuant to Section 5.4 by the fifth (5th) anniversary of the Effective Date."

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         9.       EFFECT OF TERMINATION. Section 14.2.3. of the Agreement,
entitled "Effect of Termination of Development Phase," is hereby amended to read
"In the event that Allergan delivers notice to CNSI pursuant to Section 14.2.1,
then (i) CNSI shall be free to grant a license to a Third Party for the use,
manufacture, distribution for sale and sale of such Development Compound or
Back-Up Compound for any indication, other than the treatment of (a) ophthalmic
diseases and disorders, and (b) pain, and (ii) the effects of termination set
forth under Section 14.6 hereof shall apply to such Development Compound or
Back-Up Compound."

         Except for the modifications and amendments set forth above, the
Agreement shall remain in full force and effect in accordance with its terms.

         In order to evidence your agreement with the foregoing, please sign
this letter where indicated below and return it to us.

                                 Very truly yours,

                                 ALLERGAN SALES, INC.

                                 /s/ George M. Lasezkay
                                 Corporate Vice President, Corporate Development

         Agreed to and acknowledged this 20th day of November, 1999.

                                 CAMBRIDGE NEUROSCIENCE, INC.

                                 /s/ Harry W. Wilcox
                                 President and Chief Executive Officer

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