Document:

<PAGE>

                                                          Exhibit 10.6

                                   DYAX CORP.
                    One Kendall Square, Bldg. 600, 5th Floor
                               Cambridge, MA 02139

                                September 1, 1998

Mr. Gregory D. Phelps
75 Farley Pond Lane
Needham, MA 02192

Dear Greg:

This letter sets forth our understanding of the basis on which you will now be
employed by Dyax Corp. as an executive reporting to the Chief Executive Officer.
Subject to your agreement to the terms of your employment in this letter, the
Board has elected you Vice Chairman. I understand that you will begin working
with us immediately on a substantially full-time basis (i.e. not less than three
days per week).

Dyax will pay you a base salary of $200,000 per year ($16,667 per month), which
is subject to adjustment on an annual basis by the Compensation Committee of the
Board of Directors (the "Committee"). In addition, for the 1998 calendar year,
you will be eligible for a bonus of $50,000 based on specific individual and
corporate objectives set by me, with the Committee to determine achievement of
the bonus at the end of the year. All payments shall be made to you in
accordance with Dyax's standard payroll practices.

The Committee has also granted you additional options to purchase 100,000 shares
of Dyax Common Stock vesting monthly in equal installments over 48 months
beginning with the date of your employment. Subject to your commencing
employment with the Company, I will recommend to the Committee that such
options, and the option for 48,000 shares of Dyax Common Stock previously
granted to you (the "Consulting Option"), will be substituted with new options
granted with an exercise price per share at the fair market value on the date of
grant, as determined by the Committee. In addition, I will recommend that all of
the shares subject to the substitute option for the Consulting Option will be
exercisable immediately without further vesting. All such options will be
subject to Dyax's 1995 Equity Incentive Plan and Dyax's standard terms for
options thereunder. The maximum number of such options permitted under the
Internal Revenue Code shall be treated as incentive stock options, except to the
extent that they may be required by law to be treated as nonstatutory options
upon exercise or subsequent sale of the underlying shares.

I will also recommend that in the event of a change of control of Dyax which
adversely affects your position and responsibilities as an executive of the
Company and results in termination of your employment, whether by the Company
for any reason or by yourself for good reason, Dyax agrees that fifty percent of
all shares that are subject to stock options granted to you at any time through
the termination of your employment but that are not yet exercisable as of the
date of such termination shall become exercisable immediately upon such
termination. For purposes of this offer, "change of control" shall mean a change
in ownership of more than 50% of the voting
<PAGE>

stock of the Company in one transaction or a series of related transactions by
one investor or affiliated group of investors, except as a result of any private
or public debt or equity financing the net cash proceed of which inure to Dyax;
and "termination for good reason" shall mean termination subsequent to a change
in control of the Company, and without your express written consent, based on
(i) the assignment to you of any duties inconsistent with your position, duties,
responsibilities and status with the Company immediately prior to a change in
control, or a change in your reporting responsibilities, titles or offices as in
effect immediately prior to a change in control, (ii) a reduction by the Company
in your base salary as in effect immediately before the change in control, or
(iii) the Company's requiring you to be based anywhere other than within thirty
(30) miles of your present office location, except for required travel on the
Company's business to an extent substantially consistent with your business
travel obligations before the change of control.

You will also be eligible to participate in the Company's employee benefits,
including health and dental insurance and 401(k) Savings Plan. Dyax requires
that you execute the Company's standard Employee Confidentiality Agreement (copy
attached), and comply with federal and state employment laws and regulations.

You will no longer be entitled to the cash compensation set forth in your
existing consulting agreement dated May 4, 1998 for the period after July 12,
1998. However, your acknowledgement of your new relationship as an employee of
the Company by signing this letter is not intended to supercede or otherwise
amend the terms of your prior stock options described in your consulting
agreement, which shall continue to vest so long as you are providing services to
the Company as an employee.

If this letter accurately sets forth our understanding of the basis for your
future employment by Dyax, please sign both copies of this letter and the
enclosed Employee Confidentiality Agreement and return one copy of each to me.
We are very pleased that you are now joining Dyax as an employee.

DYAX CORP.

/s/ Henry E. Blair
------------------------------------------
Henry E. Blair
Chairman and Chief Executive Officer

Acknowledged:

/s/ Gregory D. Phelps
------------------------------------------
Gregory D. Phelps

                                       2
<PAGE>

                     DYAX EMPLOYEE CONFIDENTIALITY AGREEMENT

THIS AGREEMENT (the "Agreement") is made this July 13, 1998.

BETWEEN

      DYAX CORP., a Delaware corporation, having its principal place of business
      at One Kendall Square, Bldg. 600, 5th Floor, Cambridge, MA 02139, and its
      affiliates, ("Dyax"), and

      Gregory D. Phelps (the "Employee").

1. EMPLOYEE RESTRICTIONS.

      In consideration of, and as a condition of the Employee's continued
employment with Dyax, the Employee agrees as follows:

(a) Confidential Information: As of the date of the Employee's employment by
Dyax and thereafter, the Employee shall treat as strictly confidential all
proprietary, secret, unpublished and confidential information and materials
which relate to the business or interests of Dyax, including, but not limited
to, the business plans, technical projects, trade secrets, know-how, operations,
customer lists, research datum or results, inventions, formulas, cell lines,
chemical and biological compounds, products and processes developed by or for
Dyax (the "Confidential Information"). The Employee shall not disclose or use
Confidential Information in any manner or form other than in performance of the
services required during his/her employment by Dyax.

(b) Assignment of Rights: Any and all information, data, inventions,
discoveries, formulas, biological or chemical materials, notebooks and other
work product which the Employee conceives, develops or acquires during his/her
employment with Dyax, and for a period of six (6) months after the termination
date of his/her employment with Dyax, which directly or indirectly relates to
work performed for Dyax (the "Proprietary Property"), shall be the sole and
exclusive property of Dyax. The Employee shall promptly execute any and all
documents necessary to assign this property to Dyax.

(c) Intellectual Property: During the Employee's employment at Dyax, the
Employee shall promptly assist with and execute any and all applications,
assignments or other documents which an officer or director of Dyax shall deem
necessary or useful in order to obtain and maintain patent, trademark or other
intellectual property protection for Dyax's products or services. After the
termination date of his/her employment with Dyax the Employee shall use
reasonable efforts to assist Dyax on intellectual property matters as they
relate to his/her employment, and Dyax shall reasonably compensate the Employee
for his/her time and expense.

(d) Dyax Property: Upon termination of the Employee's employment with Dyax, the
Employee shall return and deliver to Dyax all copies of Confidential Information
(as defines in (a) above) and all Proprietary Property (as defined in (b) above
and all other property furnished to the Employee by Dyax, including, without
limitation, documents, records, notebooks and

                                       3
<PAGE>

equipment. The Employee shall not take with him/her any such property, except as
expressly authorized in writing by an officer or director of Dyax.

(e) Non-Solicitation: As of the date of the Employee's employment by Dyax and
for a period of one (1) year after the termination date of his/her employment at
Dyax, the Employee shall not directly or indirectly solicit on behalf of himself
or others (i) the employment of any employees or exclusive consultants of Dyax,
or (ii) any of the business being conducted by Dyax or being actively pursued by
Dyax with any customer or partner.

2. SCOPE OF THIS AGREEMENT

(a) The provisions of this Agreement shall survive the termination of the
Employee's employment with Dyax.

(b) The Employee acknowledges that the restrictions contained in this Agreement
are reasonable in view of the nature of the business in which Dyax is engaged
and the Employee's knowledge of Dyax business.

(c) Dyax is permitted to assign its rights and obligations under this Agreement.

(d) The Employee also acknowledges that any breach of this Agreement amy cause
Dyax irreparable harm for which Dyax would be entitled to the issuance by a
court of competent jurisdiction of an injunction, restraining order or other
equitable relief in favor of restraining the Employee from committing or
continuing any violation of this Agreement. Any right to obtain such equitable
relief will not be deemed a waiver of any right to assert any other remedy or
request any other relief which Dyax may have under this Agreement or otherwise
at law or in equity.

(e) If in any jurisdiction any provision of this Agreement or its application to
any party or circumstance is restricted, prohibited or determined unenforceable,
the remaining provisions of this Agreement shall remain unaffected and
enforceable. In addition, if any provision of this Agreement shall be held to be
excessively broad as to time, duration, geographical scope, activity or subject,
the provision shall be construed so as to be enforceable to the extent
compatible with the applicable law.

(f) This Agreement shall be governed and construed in accordance with the laws
of the Commonwealth of Massachusetts.

AGREED:

      EMPLOYEE                                  DYAX  CORP.

      --------------------------                --------------------------
      (signature)                               (signature)

                                                Chairman & CEO
                                                --------------------------
                                                (title)

                                       4<PAGE>
                                                                 EXHIBIT 10.7

                         EXECUTIVE EMPLOYMENT AGREEMENT

         This Executive Employment Agreement (the "Agreement") is entered into
effective as of February 18, 1998 (the "Effective Date") between Dyax Corp. (the
"Company"), a Delaware corporation with its principal executive offices at One
Kendall Square, Building 600, Cambridge, MA 02139, and Robert A. Dishman
("Executive") residing at 37 Garland Road, Concord, Massachusetts 01742.

                                   ARTICLE 1.
                             EMPLOYMENT OF EXECUTIVE

         1.1.  EMPLOYMENT. Subject to the terms and conditions of this
Agreement, the Company agrees to employ Executive in a full time capacity to
serve as Executive Vice President of the Company and to perform such specific
duties as may reasonably be assigned to Executive from time to time by the Board
of Directors of the Company for the period commencing on the Effective Date and
continuing until terminated as herein provided. Executive hereby accepts such
employment for the term hereof.

         1.2.  NO CONFLICTING COMMITMENTS. During the period of Executive's
full time employment with the Company, Executive will not undertake any
commitments which might impair Executive's performance of his duties as a full
time employee of the Company.

         1.3.  NO RELOCATION. Although Executive is not expected to relocate
to the Company's facilities in Charlottesville, Virginia in connection with his
employment, Executive will spend sufficient time at the Company's facilities in
Charlottesville to effectively manage that business.

                                   ARTICLE 2.
                                  COMPENSATION

         For all services to be rendered by Executive to the Company pursuant to
this Agreement, the Company shall pay to Executive the compensation and provide
for Executive the benefits set forth below:

         2.1.  BASE SALARY. The Company shall pay to Executive a base salary at
the annual rate of Two Hundred Thousand Dollars ($200,000) during the first
twelve months of this Agreement, prorated during the period Executive is
employed hereunder and payable in substantially equal monthly installments.
Thereafter, Executive's salary will be reviewed and set annually by the Board of
Directors of the Company or a duly appointed committee thereof, provided,
however, that Executive's annual salary shall not be less than Two Hundred
Thousand Dollars ($200,000) as long as Executive is an Executive Vice President
of the Company.
<PAGE>

         2.2.  FRINGE BENEFITS. In addition to Executive's base salary, the
Company shall provide Executive and Executive's dependents medical insurance and
other such benefits as are generally made available by the Company to its other
full time executive employees.

         2.3.  STOCK OPTIONS. The vesting, exercise and other terms of any stock
options which have been previously granted to Executive by the Company, as well
as other stock options which may hereafter be granted to Executive at the
discretion of the Board of Directors of the Company or a duly appointed
committee thereof, shall continue in accordance with the terms of the respective
stock option grant, unless otherwise provided for herein. The Company agrees to
accelerate the vesting of the incentive stock option granted to Executive on
October 30, 1997 with respect to 60,000 shares of the Company's Common Stock
(the "1997 Option") so the option shall become fully exercisable with respect to
all of the shares as of the Effective Date.

         2.4.  RESTRICTED STOCK AWARD. The Company agrees to grant Executive a
Restricted Stock Award under its 1995 Equity Incentive Plan pursuant to which
Executive shall have the right to purchase 120,000 shares (the "Restricted
Shares") of the Company's Common Stock as Restricted Stock, at the price of
$3.00 per share, in accordance with the terms of the Restricted Stock Purchase
Agreement attached hereto as EXHIBIT A (the "Purchase Agreement").

         2.5.  LOANS TO EXECUTIVE. Subject to exercise in full by Executive of
the 1997 Option and Executive's purchase of the Restricted Stock, the Company
agrees to make two loans (the "Loans") to Executive, one in the amount of
$93,600 and the other in the amount of $360,000, on the following terms and
conditions:

         2.5.1 The Loans shall be subject to Executive's delivery to the Company
         of (i) duly executed promissory notes in substantially the forms
         attached hereto as EXHIBITS B-1 AND B-2 in the respective amounts of
         each of the Loans and (ii) duly executed pledge agreements (the "Pledge
         Agreements") for each of the Loans in substantially the forms attached
         hereto as EXHIBITS C-1 AND C-2, (iii) the stock certificates evidencing
         the shares issued upon exercise of the 1997 Option and the Restricted
         Shares, and (iv) stock powers duly executed in blank with respect to
         such shares.

         2.5.2 If Executive's employment with the Company is terminated and the
         Loans are accelerated in accordance with their terms, the $360,000 Loan
         shall be paid and discharged first by surrender of any shares of Common
         Stock still constituting Unvested Shares (as defined in the Purchase
         Agreement) as of the date of acceleration at a rate of $3.00 per share,
         and all other amounts due under such Loan as of the date of
         acceleration, as well as all amounts due with respect to the $93,600
         Loan upon its acceleration, shall be paid and discharged, at
         Executive's election, in cash or by surrender of shares of Common Stock
         of the Company at the then fair market value thereof, or any
         combination thereof. For purposes of this Agreement, the fair market
         value of the Company's capital stock shall mean (i) with respect to
         securities registered under the Securities Exchange Act of 1934, as
         amended (the "Exchange Act"), the average of the high and low sale
         prices of such securities reported on the Nasdaq Stock Market, or if
         such securities are not reported on such market, the average of the
         high and

                                      - 2 -
<PAGE>

         low bid quotations reported by the National Association of Securities
         Dealers ("NASD"), which in each case shall be determined by Dyax in
         good faith and may be based upon the reports published in the Eastern
         Edition of The Wall Street Journal or any other reporting service
         reasonably relied upon by Dyax; and (ii) with respect to securities not
         registered under the Exchange Act, the fair market value as determined
         in good faith by the Board of Directors of Dyax.

         2.5.3 So long as Executive is employed by the Company, on each
         anniversary of the Loans during the term thereof the Company shall
         forgive the accrued interest due thereon through the date of such
         anniversary. If Executive's employment is terminated before any such
         anniversary, the Company shall forgive the accrued interest (i) on the
         $360,000 Loan through the date of termination and (ii) on the $93,600
         Loan through the date of termination or, in the case of a termination
         pursuant to Sections 3.1.1, 3.1.2 or 3.1.4, through the second
         anniversary of the date of issue of such Loan if such second
         anniversary is later than the date of termination.

                                   ARTICLE 3.
                                  TERMINATION

         3.1.  TERMINATION.  Executive's employment hereunder shall terminate
upon the occurrence of any of the following events:

               3.1.1.  Executive's death or legal incapacity;  or

               3.1.2.  The termination of Executive's employment hereunder by
         the Board of Directors of the Company, at its option, to be exercised
         by written notice to Executive, upon Executive's other incapacity or
         inability to further perform services as contemplated herein for a
         period aggregating 90 days or more within any six-month period because
         Executive's physical or mental health shall have become impaired so as
         to make it impossible or impractical to perform the duties and
         responsibilities contemplated hereunder; or

               3.1.3.  The termination of Executive's employment hereunder by
         the Board of Directors of the Company, at its option, to be exercised
         by written notice to Executive, in the event of Executive's gross
         neglect of duties hereunder or commission of an act of dishonesty or
         moral turpitude in connection with employment, as determined in good
         faith by the Board of Directors; or

               3.1.4.  The termination of Executive's employment hereunder by
         the Board of Directors of the Company, at its option which may be
         exercised with or without cause, to be exercised by written notice to
         Executive;  or

               3.1.5.  The termination of Executive's employment hereunder by
         Executive, to be exercised by delivery of thirty (30) days prior
         written notice from Executive to the Company.

                                      - 3 -
<PAGE>

         3.2.  PAYMENTS UPON TERMINATION.  Notwithstanding any other provisions
in this Agreement to the contrary:

               3.2.1.  If Executive's employment with the Company terminates
         pursuant to Sections 3.1.1., 3.1.2., 3.1.3., or 3.1.5., all payments
         and benefits provided to Executive under this Agreement shall cease as
         of the date of termination of employment.

               3.2.2.  If Executive's employment with the Company terminates
         pursuant to Section 3.1.4., (i) the payment of Executive's base salary
         and all benefits provided to Executive under this Agreement shall
         continue for an initial period of six (6) months after the date of
         termination of employment; (ii) in the event that Executive has not
         obtained alternative, comparable employment by the end of the initial
         period of six months, the payment of Executive's base salary and all
         benefits provided to Executive under this Agreement shall continue for
         an additional period of six (6) months after the initial period
         specified in clause (i) of this Section, provided, however, that the
         amount of any compensation or benefits payable to Executive shall be
         reduced by any compensation or consulting income earned by Executive
         during such additional six month period; and (iii) all stock options
         (as referenced in Section 2.3) held by Executive at his termination
         date shall become immediately exercisable and shall remain exercisable
         for a period of ninety (90) days following his termination date.

         3.3.  NO DUTY TO MITIGATE. Executive shall not be required to mitigate
the amount of any payment provided for in Section 3.2.2.(i) by seeking other
employment or otherwise, and the amount of any payment or benefit provided for
in Section 3.2.2.(i) shall not be reduced by any compensation earned by
Executive as the result of employment by another employer after the date of
termination.

                                   ARTICLE 4.
                 COVENANTS AGAINST COMPETITION WITH THE COMPANY

         4.1.  NON-SOLICITATION OF EMPLOYEES. Executive agrees that during the
term of Executive's employment with the Company and for a period of twelve (12)
months after the later of (i) termination of Executive's employment with the
Company for any reason or (ii) cessation of payments to Executive pursuant to
Section 3.2.2., Executive shall not directly or indirectly recruit, solicit or
otherwise induce or attempt to induce any employees of the Company to leave the
employment of the Company.

         4.2.  NON-COMPETITION.  In the event Executive's employment with the
Company is terminated by the Company for any reason other than a termination
without cause under Section 3.1.4., Executive agrees that during the term of
Executive's employment with the Company and for a period of twelve (12) months
after the effective date of his termination (the "Non- competition Period")
Executive shall not directly or indirectly, sell, attempt to sell or otherwise
market to customers of the Company products or services which are competitive
with those offered, sold or provided by the Company or any of its subsidiaries.
If Executive's employment

                                      - 4 -
<PAGE>

with the Company is terminated by the Company without cause under Section
3.1.4., the Non-competition Period shall be limited to the period during which
the Company is making payments to Executive pursuant to Section 3.2.2.,
provided, however, that the Company may at its option continue to make such
payments for a maximum of twelve (12) months following the effective date of
Executive's termination.

                                   ARTICLE 5.
                            CONFIDENTIAL INFORMATION

         5.1.  MAINTENANCE OF CONFIDENTIALITY. Executive agrees that Executive
will not (except as required in the course of employment with the Company), both
during the term of Executive's employment with the Company and for a period of
five (5) years thereafter, communicate or divulge to, or use for Executive's own
benefit or the benefit of any other person, firm or organization, any
confidential and proprietary information of the Company and its subsidiaries.

         5.2.  OWNERSHIP OF CONFIDENTIAL INFORMATION. Records, files, memoranda,
reports, price lists, customer lists, drawings, plans, sketches and documents
and the like , relating to the business of the Company, which Executive shall
use or prepare or come into contact with in the course of, in connection with,
or as a result of employment with the Company, shall remain the Company's sole
and exclusive property.

                                   ARTICLE 6.
                             OWNERSHIP OF INVENTIONS

         6.1.  "INVENTION" DEFINED. As used in this Agreement, "Invention" means
any invention, discovery or innovation with regard to chromatography, chemistry,
enzymology, biotechnology, genetic engineering or recombinant DNA technology,
whether or not patentable, made, conceived, or first actually reduced to
practice by Executive, alone or jointly with others, in the course of, in
connection with, or as a result of his service as an executive of the Company,
including any art, method, process, machine, manufacture, design or composition
of matter, or any improvement thereof, or any variety of plant or microorganism.

         6.2.  DISCLOSURE OF INVENTIONS. Each Invention made, conceived or first
actually reduced to practice by Executive, whether alone or jointly with others,
in the course of, in connection with, or as a result of his service as an
executive of the Company, shall be promptly disclosed in writing to the Company
(or such officer of the Company as the Board of Directors may designate). Such
report shall be sufficiently complete in technical detail and appropriately
illustrated by sketch or diagram to convey to one skilled in the art to which
the Invention pertains, a clear understanding of the nature, purpose,
operations, and to the extent known, the physical, chemical, biological or
electrical characteristics of the Invention.

         6.3.  OWNERSHIP OF INVENTIONS. Each Invention, as herein defined,
shall be the sole and exclusive property of the Company.

                                      - 5 -
<PAGE>

         6.4.  ASSIGNMENT OF TITLE. Executive agrees to execute an assignment to
the Company or its nominee of Executive's entire right, title and interest in
and to any Invention, without compensation beyond that provided in this
Agreement. Executive further agrees, upon the request of the Company and at its
expense, that Executive will execute any other instrument and document necessary
or desirable in applying for and obtaining patents in the United States and in
any foreign country with respect to any Invention. Executive further agrees,
whether or not Executive is then an employee of the Company, to cooperate to the
extent and in the manner reasonably requested by the Company in the prosecution
or defense of any claim involving a patent covering any Invention or any
litigation or other claim or proceeding involving any invention covered by this
Agreement, but all expenses thereof shall be paid by the Company.

                                   ARTICLE 7.
                                  MISCELLANEOUS

         7.1.  COUNTERPARTS. This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, and all of which
together shall be deemed to be one and the same instrument.

         7.2.  BINDING EFFECT. This Agreement shall inure to benefit of and be
binding upon the parties hereto and their respective lawful successors and
assigns and upon Executive's heirs and personal representatives.

         7.3.  ASSIGNMENT. Neither this Agreement nor any rights or obligations
hereunder shall be assignable by either party hereto without the prior written
consent of the other party.

         7.4.  NOTICES. All notices, requests, demands or other communications
to be given pursuant to this Agreement shall be in writing and shall be deemed
to have been duly given if delivered by hand or mailed by registered or
certified mail, return receipt requested, postage prepaid, as follows.

         If to the Company, to:

         Dyax Corp.
         One Kendall Square, Building 600
         Cambridge, Massachusetts 02139
         Attention: Chief Executive Officer

         If to Executive, to:

         37 Garland Road
         Concord, Massachusetts 01742

         with a copy to:

                                      - 6 -
<PAGE>

         Joseph B. Darby III, Esq.
         Sherburne, Powers & Needham, P.C.
         One Beacon Street
         Boston, Massachusetts 02108

or such other address as either party hereto shall have designated by notice in
writing to the other party.

         7.5.  ENTIRE AGREEMENT; AMENDMENTS. This Agreement and the attached
exhibits constitute the entire agreement and understanding between the parties
hereto with respect the subject matter hereof and supersedes all prior
agreements and understanding relating to such subject matter, including without
limitation the Executive Employment Agreement dated April 1, 1994 between the
parties. This Agreement may be amended, supplemented or otherwise modified at
any time, but only by an instrument in writing signed by the parties hereto.

         7.6.  GOVERNING LAW. This Agreement and the legal relations among the
parties hereto shall be governed by and construed in accordance with the laws
of the Commonwealth of Massachusetts.

         7.7.  SEVERABILITY. In case any provision hereof shall, for any reason,
be held to be invalid or unenforceable in any respect, such invalidity or
unenforceability shall not affect any other provision hereof, and this Agreement
shall be construed as if such invalid or unenforceable provision had not been
included herein. If any provision hereof shall, for any reason, be held by a
court to be excessively broad as to duration, geographical scope, activity or
subject matter, it shall be construed by limiting and reducing it to make it
enforceable to the extent compatible with applicable law as then in effect.

         7.8.  SURVIVAL. Section 2.5, 3.2.2 and Articles 4, 5 and 6 shall
survive the termination of this Agreement for the periods of time indicated
therein or indefinitely if no period of time is indicated.

                                      - 7 -
<PAGE>

         IN WITNESS WHEREOF, the undersigned have duly executed and delivered
this Agreement as of the date first above written.

DYAX CORP.

By: /s/ Henry E. Blair
    ---------------------------
    Henry E. Blair
    Chairman, President & CEO

/s/ Robert A. Dishman
-------------------------------
Robert A. Dishman, individually

                                      - 8 -
<PAGE>

                                                                      EXHIBIT A

                                   DYAX CORP.

                       RESTRICTED STOCK PURCHASE AGREEMENT

         This Restricted Stock Purchase Agreement (this "Agreement") is dated as
of February __, 1998 (the "Effective Date"), by and between Dyax Corp., a
Delaware corporation (the "Company"), and Robert A. Dishman ("Purchaser").

                                    RECITALS

         A.   The Company and Purchaser have entered into an Executive
Employment Agreement (the "Employment Agreement") of even date herewith which
provides in part that the Company shall issue and sell certain "Restricted
Stock" to Executive on the terms herinafter set forth.

         B.   The Company desires to issue and sell, and Purchaser desires to
purchase, shares of Common Stock of the Company, on the terms and conditions
hereinafter set forth, as "Restricted Stock" issued pursuant to the Company's
1995 Equity Incentive Plan (as amended to date, the "Plan"). Capitalized terms
not otherwise defined herein have the meanings given to them in the Plan.

         Accordingly, it is agreed between the parties as follows:

         1.   Purchaser hereby agrees to purchase from the Company, and the
Company agrees to sell to Purchaser, 120,000 shares (hereinafter sometimes
collectively referred to as the "Stock") of the Company's Common Stock, par
value $0.01 per share, for a purchase price of $3.00 per share, payable at the
closing in cash or by delivery of a secured promissory note of Purchaser in form
and on terms satisfactory to the Company. The closing hereunder shall be deemed
to have occurred on the Effective Date or at such later date, not later than
fifteen days thereafter, as the Company receives payment of the purchase price.

         2.   For the purposes of this Section 2, the shares of Stock purchased
pursuant to this Agreement shall vest in twenty-four (24) substantially equal
monthly installments (any fractional shares to be cumulated and to become
exercisable at the end of the earliest succeeding monthly period in which a
whole share equivalent is accumulated) beginning on the twenty-fifth monthly
anniversary of the Effective Date, with all shares being fully vested on the
fourth anniversary of the Effective Date; provided, however, that such vesting
shall be accelerated and all of the Stock shall become fully vested on the
occurrence of a Vesting Event. "Vesting Event" shall mean (i) an underwritten
public offering of the Company's capital stock or (ii) any merger, consolidation
or other sale of the Company involving a transaction or series of simultaneous
transactions in which the stockholders of the Company immediately before the
transaction(s) own less than 50% of the capital stock of the resulting or
purchasing entity immediately after completion of the transaction(s).

                                      - 9 -
<PAGE>

              (a)  All of the shares of Stock being purchased by Purchaser
pursuant to this Agreement that are not vested (the "Unvested Shares") shall be
subject to the repurchase right ("Repurchase Right") set forth in this Section
2. If Purchaser shall cease to employed by the Company, then the Company may
exercise the Repurchase Right, as provided in Section 2(b) below, at the $3.00
purchase price per share set forth in Section 1 above (the "Repurchase Price")
with respect to all the Unvested Shares as of the date of such termination;
provided, however, that if Executive is terminated by the Company without cause
pursuant to Section 3.1.4 of the Employment Agreement, then (i) no repurchase
shall occur before 180 days after the date of such termination and (ii) the
Repurchase Right shall terminate if a Vesting Event occurs before 180 days after
such termination. Notwithstanding the foregoing, all shares of Stock shall be
subject to the First Refusal right set forth in Section 3 hereof.

              (b)  In the event Purchaser shall cease to be employed by the
Company (including a parent or subsidiary of the Company, if any), the Company
shall have the right, at any time within sixty (60) days after the date
Purchaser's employment ceases, to exercise the Repurchase Right, which consists
of the right to purchase from Purchaser (or his personal representative, as the
case may be) all Unvested Shares at the Repurchase Price; provided, however,
that if Purchaser's employment has been terminated without cause pursuant to
Section 3.1.4 of the Employment Agreement, then the Repurchase Right may only be
exercised by the Company after 180 days, and before 240 days, after the date of
such termination.

              (c)  If Purchaser is required to transfer his shares of Stock
by operation of law (other than death of Purchaser) or by order or decree of any
court, then the Company shall have the option, exercisable at any time during
the period of sixty (60) days after receiving notice thereof, to purchase all of
the Unvested Shares for the Repurchase Price and upon the terms as set forth in
Section 4. Failure of the Company to elect to purchase Purchaser's Unvested
Shares of Stock under this Section 2 shall not affect the right to purchase the
same shares under Section 3(a) in the event of a proposed sale, assignment,
transfer, exchange, pledge or other disposition by or to any receiver,
petitioner, assignee, transferee or other person obtaining an interest in said
shares.

              (d)  Nothing in this Agreement shall affect in any manner
whatsoever the right or power of the Company, or a parent or subsidiary of the
Company, to terminate Purchaser's provision of services to the Company, for any
reason, with or without cause.

         3.   (a)  So long as the First Refusal Right has not terminated as
set forth in Section 3(f) below, Purchaser shall not sell or otherwise transfer
any shares of Stock unless prior to any sale or other transfer thereof,
Purchaser (or his personal representative, as the case may be) shall provide the
Company with written notice, in the manner provided in Section 14 hereof,
describing the number of shares of Stock intended to be sold or transferred, the
price and the general terms of the proposed sale or transfer.

              (b)  The Company shall have the right (the "First Refusal
Right") at any time within sixty (60) days after the notice required by Section
3(a) above to purchase from Purchaser (or his personal representative, as the
case may be) up to but not exceeding the number of shares

                                     - 10 -
<PAGE>

of the Stock specified in, and at the price (the "First Refusal Price") and upon
the general terms specified in such notice.

              (c)  If the First Refusal Right is not exercised with respect
to some or all the shares of the Stock specified in the notice required by
Section 3(a) hereof, then for a period of 120 days, Purchaser (or his personal
representative, as the case may be) shall be free to sell, or otherwise
transfer, up to but not exceeding the number of shares of the Stock specified in
the notice required by Section 3(a) hereof, minus the number of shares of the
Stock with respect to which the First Refusal Right was exercised, at a price
and upon general terms no more favorable to purchasers or transferees thereof
than specified in the notice required by Section 3(a) hereof.

              (d)  In the event that any shares of the Stock which are free
to be sold or otherwise transferred within said 120-day period are not so
transferred, such shares of the Stock shall again be subject to the First
Refusal Right and Purchaser (or his personal representative, as the case may be)
shall comply with all the provisions of this Section 3 prior to selling or
otherwise transferring any such shares of the Stock.

              (e)  Failure to exercise the First Refusal Right with respect
to any shares of the Stock shall not constitute a waiver of the First Refusal
Right with respect to any other shares of the Stock.

              (f)  The First Refusal Right shall continue after Purchaser's
death or the termination of Purchaser's employment with the Company for any
reason, or no reason, and shall terminate only upon the closing of an
underwritten public offering pursuant to an effective registration statement
under the Securities Act of 1933, as amended, covering the offer and sale of
shares of Common Stock of the Company to the public at a public offering price
of not less than $4.50 per share (as adjusted for stock splits, stock dividends,
distributions or subdivisions) and resulting in gross proceeds to the Company of
not less than Ten Million Dollars ($10,000,000).

              (g)  Notwithstanding the foregoing, Purchaser may transfer any
vested shares of Stock (a "Permitted Transfer") to or for the benefit of any
Permitted Transferee (as defined below) without complying with the provisions of
Sections 3(a) and 3(b), provided that such shares shall remain subject to this
Agreement and such Permitted Transferee shall, as a condition to such transfer,
deliver to the Company a written instrument confirming that such transferee
shall be bound by all of the terms and conditions of this Agreement. For the
purposes of this Agreement, a "Permitted Transferee" shall mean (i) any pledgee
pursuant to a pledge of the shares of Stock made pursuant to a bona fide loan
transaction that creates a security interest; or (b) any spouse, child or
grandchild, or to a trust for their benefit or for the benefit of Purchaser,
whether such transfer is made upon death or by intervivos transfer.

         4.   The Repurchase Right and the First Refusal Right shall be
exercised by written notice signed by an officer of the Company and delivered or
mailed as provided in Section 14 hereof. The Repurchase Price or the First
Refusal Price, as the case may be, shall be payable,

                                     - 11 -
<PAGE>

at the option of the Company, in cancellation of all or a portion of any
outstanding indebtedness of Purchaser to the Company or in cash (by check) or
both.

         5.   The Company may assign its rights under Sections 2 and 3 hereof.

         6.   If, from time to time during the term of the Repurchase Right or
the First Refusal Right:

              (a)  There is any stock dividend or liquidating dividend of
cash/or property, stock split or other change in the character or amount of any
of the outstanding securities of the Company; or

              (b)  There is any consolidation, merger or sale of all or
substantially all, of the assets of the Company unless such consolidation,
merger or sale is with a publicly-owned corporation and the aggregate market
value of the securities or other property the stockholders of the Company
receive is in excess of Ten Million Dollars ($10,000,000), then, in such event,
any and all new, substituted or additional securities or other property (other
than cash) to which Purchaser is entitled by reason of his ownership of Stock
shall be immediately subject to the Repurchase Right or the First Refusal Right,
as the case may be, and be included in the word "Stock" for all purposes of the
Repurchase Right and the First Refusal Right with the same force and effect as
the shares of Stock subject to the Repurchase Right and the First Refusal Right
under the terms of Section 2 and 3 hereof. While the total Repurchase Price
shall remain the same after each such event, the Repurchase Price per share of
Stock upon exercise of the Repurchase Right shall be appropriately adjusted.
Stock acquired as provided in clauses (a) or (b) above shall be deemed to have
been acquired at the time of acquisition of the Stock on which such Stock was
distributed.

         7.   All certificates representing any shares of Stock subject to
the provisions of this Agreement shall have endorsed thereon the following
legends:

              (a)  "Any disposition of any interest in the securities
represented by this certificate is subject to restrictions, and the securities
represented by this certificate are subject to a repurchase right and a first
refusal right contained in a certain agreement between the record holder hereof
and the corporation, a copy of which will be mailed to any holder of this
certificate without charge after receipt by the corporation of a written request
therefor."

              (b)  Any legend required to be placed thereon by federal or state
securities laws.

         8.   Purchaser acknowledges that he is aware that the Stock to be
issued to him by the Company pursuant to this Agreement has not been registered
under the Securities Act of 1933, as amended. In this connection, Purchaser
warrants and represents to the Company as follows:

              (a)  Purchaser is purchasing the Stock solely for its own account
for investment and not with a view to or for sale or distribution of the Stock
or any portion thereof and not with

                                     - 12 -
<PAGE>

any present intention of selling, offering to sell or otherwise disposing of or
distributing the Stock or any portion thereof. Purchaser also represents that
the entire legal and beneficial interest of the Stock which Purchaser is
purchasing is being purchased for, and will be held for the account of,
Purchaser only and neither in whole nor in part for any other person.

              (b)  Purchaser has heretofore discussed the Company and its
plans, operations and financial condition with its officers and Purchaser has
heretofore received all such information as Purchaser deems necessary and
appropriate to enable Purchaser to evaluate the financial risk inherent in
making an investment in the Stock of the Company and Purchaser further
represents and warrants that Purchaser has received satisfactory and complete
information concerning the business and financial condition of the Company in
response to all inquiries in respect thereof.

              (c)  Purchaser realizes that its purchase of the Stock will be
a highly speculative investment and that Purchaser is able, without impairing
its financial condition, to hold the Stock for an indefinite period of time and
to suffer a complete loss on his investment.

              (d)  The Company has disclosed (or hereby does disclose) to
Purchaser in writing:

                   (i)   the sale of the Stock which it is purchasing has not
                         been registered under the Securities Act of 1933, as
                         amended (the "Act"), and the Securities must be held
                         indefinitely unless a transfer of them is subsequently
                         registered under the Act or an exemption from such
                         registration is available;

                   (ii)  the share certificate representing the Stock will be
                         stamped with the legends restricting transfer specified
                         in this Agreement between the Company and Purchaser;
                         and

                   (iii) the Company will make a notation in its records of the
                         aforementioned restrictions on transfer and legends.

              (e)  Purchaser understands that the shares of Stock are restricted
securities within the meaning of Rule 144 promulgated under the Act; that the
exemption from registration under Rule 144 will not be available in any event
for at least two years from the date of sale of the Stock to it, and even then
will not be available unless (i) a public trading market then exists for the
Stock of the Company, (ii) adequate current public information concerning the
Company is then available to the public, (iii) it has been the beneficial owner
and it has paid the full purchase price for the Stock at least two years prior
to the sale, and (iv) other terms and conditions of Rule 144 are complied with;
and that any sale of the Stock may be made by it only in limited amounts in
accordance with such terms and conditions, as amended from time to time.

              (f)  Without in any way limiting its representations set forth
above, Purchaser further agrees that it shall in no event make any disposition
of all or any portion of the Stock

                                     - 13 -
<PAGE>

which it is purchasing unless and until:

                   (i)   There is then in effect a Registration Statement under
                         the Act covering such proposed disposition and such
                         disposition is made in accordance with said
                         Registration Statement: or

                   (ii)  (A) It shall have notified the Company of the proposed
                         disposition and shall have furnished the Company with a
                         detailed statement of circumstances surrounding the
                         proposed disposition, (B) it shall have furnished the
                         Company with an opinion of its own counsel to the
                         effect that such disposition will not require
                         registration of such shares under the Act, and (C) such
                         opinion of its counsel shall have been concurred in by
                         counsel for the Company and the Company shall have
                         advised it of such concurrence.

         9.   The Company shall not be required (a) to transfer on its books any
shares of Stock of the Company which shall have been sold or transferred in
violation of any of the provisions set forth in this Agreement or (ii) to treat
as owner of such shares or to accord the right to vote as such owner or to pay
dividends to any transferee to whom such shares shall have been so transferred.
In the event of a sale of Stock by Purchaser pursuant to Section 3(c) hereof,
Purchaser shall furnish to the Company proof that such sale was made in
compliance with the provisions of Section 3(c) hereof as to price and general
terms of such sale.

         10.  Subject to the provisions of this Agreement, Purchaser shall,
during the term of this Agreement, exercise all rights and privileges of a
shareholder of the Company with respect to the Stock.

         11.  If Purchaser makes an election under Section 83(b) of the Code, he
will provide a copy thereof to the Company within thirty days of the filing of
such election with the Internal Revenue Service.

         12.  Purchaser shall pay to the Company, or make provision satisfactory
to the Committee for payment of, any taxes required by law to be withheld in
respect of the Restricted Stock no later than the date of the event creating the
tax liability. In the Committee's discretion, such tax obligations may be paid
in whole or in part in shares of Common Stock, including the Restricted Stock,
valued at Fair Market Value on the date of delivery. The Company and its
Affiliates may, to the extent permitted by law, deduct any such tax obligations
from any payment of any kind otherwise due to Purchaser.

         13.  Any determination by the Committee under, or interpretation
of the terms of, this Agreement or the Plan will be final and binding on
Purchaser.

         14.  Any notice required or permitted hereunder by any party hereto
shall be given in writing and shall be deemed effectively given upon personal
delivery or upon deposit in the

                                     - 14 -
<PAGE>

United States Post Office, by registered or certified mail with postage and fees
prepaid, addressed to the other party hereto at such other party's address
hereinafter shown below such other party's signature or at such other address as
such other party may have designated by ten days' advance written notice to such
party.

         15.  This Agreement shall inure to the benefit of the successors and
assigns of the Company and be binding upon Purchaser and his heirs, executors,
administrators, successors and assigns.

         16.  This Agreement shall be governed by and interpreted under the
laws of the State of Delaware.

         17.  This Agreement may be executed simultaneously in any number of
counterparts, each of which shall be deemed to be an original, but all of which
together shall constitute one and the same instrument.

                                     - 15 -
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement
under seal as of the day and year first above written.

                                   DYAX CORP.

                                   By:
                                       ------------------------------------
                                           Henry E. Blair
                                           President

                                           Address: One Kendall Square
                                                    Building 600, 5th Floor
                                                    Cambridge, MA  02139

                                   PURCHASER:

                                   ----------------------------------------
                                   Robert A. Dishman, individually

                                           Address: 37 Garland Road
                                                    Concord, MA 01742

                                     - 16 -
<PAGE>

                                                                    EXHIBIT B-1

                                 PROMISSORY NOTE

$93,600.00                                             Cambridge, Massachusetts
                                                              February 18, 1998

         For value received, the undersigned Robert A. Dishman of Concord,
Massachusetts 01742 (the "Borrower") promises to pay to Dyax Corp. ("Dyax"), the
principal sum of Ninety-Three Thousand Six Hundred Dollars ($93,600.00), with
interest on the unpaid principal balance at a rate of five and
sixty-nine/hundredths percent (5.69%) per annum, or if higher, at such rate as
may be necessary from time to time to avoid the imputation of interest under
sections 1274 or 7872 of the Internal Revenue Code of 1986 (or corresponding
provisions of subsequent laws), as amended. Interest shall accrue from the date
hereof on the unpaid principal balance and shall be due and payable annually on
each February 18. The principal amount of this note and all accrued and unpaid
interest thereon shall be due and payable on February 18, 2002; provided,
however, that if a Vesting Event (as defined in the Restricted Stock Purchase
Agreement (the "Purchase Agreement") dated as of February 18, 1998 between the
Borrower and Dyax) has occurred, the foregoing shall be due and payable on the
later of (i) the Vesting Event and (ii) February 18, 2000. Except as otherwise
provided in Section 2.5.3 of the Executive Employment Agreement (the "Employment
Agreement") dated as of February 18, 1998 between the Borrower and Dyax,
payments of principal and interest shall be made in lawful money of the United
States of America at the principal office of Dyax in Massachusetts, or by check
mailed to such other place as the holder hereof shall designate.

         At the option of the holder, this note shall immediately become due and
payable upon occurrence of any of the following events (each an "Event of
Default"): (i) default in the payment of any installment of principal or
interest due hereunder and not otherwise forgiven under the Employment
Agreement; (ii) termination of the Borrower's employment as an officer of Dyax
other than a termination pursuant to Sections 3.1.1 or 3.1.2 of the Employment
Agreement or a termination without cause pursuant to Section 3.1.4 of the
Employment Agreement.

         The unpaid balance hereof may be paid in part or in full at any time
without penalty. All prepayments shall be applied first to the payment of
principal.

         This note is secured pursuant to a certain Pledge Agreement (as the
same may be amended from time to time, hereinafter referred to as the "Pledge
Agreement"), dated as of February 18, 1998 granted by the Borrower in favor of
Dyax, and Dyax by its acceptance hereof, shall be entitled to the benefits, and
subject to the terms, of the Pledge Agreement.

         The undersigned agrees to pay, upon maturity (by acceleration or
otherwise), costs of collection, including reasonable attorneys' fees.

                                     - 17 -
<PAGE>

         No delay or omission on the part of the holder in exercising any right
hereunder shall operate as a waiver of such right or of any other right of such
holder; nor shall any delay, omission or waiver on any occasion be deemed a bar
to or waiver of the same or any other right on any future occasion. The
undersigned and every indorser or guarantor of this note regardless of the time,
order or place of signing waives presentment, demand, protest and notices of
every kind and assents to any one or more extensions or postponements of the
time of payment or any other indulgences, to any substitutions, exchanges or
releases of collateral if at any time there be available to the holder
collateral for this note, and to the additions or releases of any other parties
or persons primarily or secondarily liable.

         All rights and obligations hereunder shall be governed by and construed
in accordance with the law of the Commonwealth of Massachusetts and this note
shall be deemed to be under seal.

                                                -------------------------------
                                                Robert A. Dishman, individually

                                     - 18 -
<PAGE>

                                                                    EXHIBIT B-2

                                 PROMISSORY NOTE

$360,000.00                                            Cambridge, Massachusetts
                                                              February 18, 1998

         For value received, the undersigned Robert A. Dishman of Concord,
Massachusetts 01742 (the "Borrower") promises to pay to Dyax Corp. ("Dyax"), the
principal sum of Three Hundred Sixty Thousand Dollars ($360,000.00), with
interest on the unpaid principal balance at a rate of five and
sixty-nine/hundredths percent (5.69%) per annum, or if higher, at such rate as
may be necessary from time to time to avoid the imputation of interest under
sections 1274 or 7872 of the Internal Revenue Code of 1986 (or corresponding
provisions of subsequent laws), as amended. Interest shall accrue from the date
hereof on the unpaid principal balance and shall be due and payable annually on
each February 18. The principal amount of this note and all accrued and unpaid
interest thereon shall be due and payable on February 18, 2002; provided,
however, that if a Vesting Event (as defined in the Restricted Stock Purchase
Agreement (the "Purchase Agreement") dated as of February 18, 1998 between the
Borrower and Dyax) has occurred, the foregoing shall be due and payable on the
later of (i) the Vesting Event and (ii) February 18, 2000. Except as otherwise
provided in Section 2.5.3 of the Executive Employment Agreement (the "Employment
Agreement") dated as of February 18, 1998 between the Borrower and Dyax,
payments of principal and interest shall be made in lawful money of the United
States of America at the principal office of Dyax in Massachusetts, or by check
mailed to such other place as the holder hereof shall designate.

         At the option of the holder, this note shall immediately become due and
payable upon occurrence of any of the following events (each an "Event of
Default"): (i) default in the payment of any installment of principal or
interest due hereunder and not otherwise forgiven under the Employment
Agreement; (ii) termination of the Borrower's employment as an officer of Dyax
other than a termination without cause pursuant to Section 3.1.4 of the
Employment Agreement; and (iii) in the case of any termination without cause
pursuant to Section 3.1.4 of the Employment Agreement, the earlier of (A) a
Vesting Event, and (B) the date of Dyax's repurchase of any of the Borrower's
Unvested Shares (as defined in the Purchase Agreement).

         The unpaid balance hereof may be paid in part or in full at any time
without penalty. All prepayments shall be applied first to the payment of
principal.

         This note is secured pursuant to a certain Pledge Agreement (as the
same may be amended from time to time, hereinafter referred to as the "Pledge
Agreement"), dated as of February 18, 1998 granted by the Borrower in favor of
Dyax, and Dyax by its acceptance hereof, shall be entitled to the benefits, and
subject to the terms, of the Pledge Agreement.

         The undersigned agrees to pay, upon maturity (by acceleration or
otherwise), costs of

                                     - 19 -
<PAGE>

collection, including reasonable attorneys' fees.

         No delay or omission on the part of the holder in exercising any right
hereunder shall operate as a waiver of such right or of any other right of such
holder; nor shall any delay, omission or waiver on any occasion be deemed a bar
to or waiver of the same or any other right on any future occasion. The
undersigned and every indorser or guarantor of this note regardless of the time,
order or place of signing waives presentment, demand, protest and notices of
every kind and assents to any one or more extensions or postponements of the
time of payment or any other indulgences, to any substitutions, exchanges or
releases of collateral if at any time there be available to the holder
collateral for this note, and to the additions or releases of any other parties
or persons primarily or secondarily liable.

         All rights and obligations hereunder shall be governed by and construed
in accordance with the law of the Commonwealth of Massachusetts and this note
shall be deemed to be under seal.

                                                -------------------------------
                                                Robert A. Dishman, individually

                                     - 20 -
<PAGE>

                                                                    EXHIBIT C-1

                                PLEDGE AGREEMENT

         THIS PLEDGE AGREEMENT (this "Agreement") dated as of February 18, 1998
is made by Robert A. Dishman (the "Borrower"), residing at 37 Garland Road,
Concord, Massachusetts 01742, in favor of Dyax Corp. ("Dyax"), a Delaware
corporation with its principal place of business at One Kendall Square, Building
600, Cambridge, Massachusetts 02139.

                                    RECITALS

         1.   Dyax has agreed to make a $93,600 loan (the "Loan") to the
Borrower on or after the date hereof evidenced by a promissory note of the
Borrower in the original principal amount of $93,600 (the "Note").

         2.   Dyax is willing to make the Loan upon the condition, among others,
that the Borrower enter into this Agreement to secure the Liabilities (as
defined in Section 11 hereof).

         NOW, THEREFORE, for and in consideration of the premises and the Loan
made by Dyax and other good and valuable consideration, the receipt of which is
hereby acknowledged, and intending to be legally bound hereby, the Borrower
represents, warrants, covenants and agrees as follows:

         1.   PLEDGE. To secure the prompt, punctual, and faithful performance
of all and each of the present and future Liabilities of the Borrower to Dyax,
the Borrower hereby grants to Dyax, a security interest in and to, and assigns,
pledges, and delivers to Dyax certificates representing certain shares of the
Common Stock of Dyax issued to the Borrower as of the date hereof or issuable to
the Borrower hereafter ("Pledged Securities"), together with appropriate undated
stock powers duly executed in blank, and all products, proceeds, substitutions,
additions, interest, dividends, and other distributions in respect thereto, as
described in Section 2 below (all of which are referred to hereinafter as the
"Collateral").

         2.   STOCK DIVIDENDS, DISTRIBUTIONS, ETC. If, while this Agreement is
in effect, the Borrower shall become entitled to receive or shall receive any
stock certificate (including, without limitation, any certificate representing a
stock dividend or a distribution in connection with any reclassification,
increase or reduction of capital, or issued in connection with any
reorganization), whether as an addition to, in substitution of or in exchange
for any shares of any Pledged Securities, or otherwise, the Borrower agrees to
accept the same as agent for Dyax and to hold the same in trust on behalf of and
for the benefit of Dyax and to deliver the same forthwith to Dyax in the exact
form received, with the indorsement of the Borrower when necessary and/or with
appropriate undated stock powers duly executed in blank, to be held by Dyax as
part of the Collateral. In case any distribution of capital shall be made on or
in respect of the Pledged Securities or any property shall be distributed upon
or with respect to the Pledged Securities pursuant to the recapitalization or
reclassification of the capital of Dyax or pursuant

                                     - 21 -
<PAGE>

to the reorganization thereof, the property so distributed shall be delivered to
Dyax as Collateral. All sums of money and property so paid or distributed in
respect of the Pledged Securities which are received by the Borrower shall,
until paid or delivered to Dyax, be held by the Borrower in trust as Collateral.

         3.   CASH DIVIDENDS; VOTING RIGHTS. Unless a Default (as defined in
Section 6) has occurred and is continuing, the Borrower shall be entitled to
receive all cash dividends paid in respect of the Pledged Securities, to vote
the Pledged Securities and to give consents, waivers and ratifications, and to
take other action in respect of the Pledged Securities. After the occurrence and
during the continuance of any Default, Dyax shall have the right, upon notice to
the Borrower, to receive all cash dividends paid in respect of the Pledged
Securities and to exercise voting rights as specified in Section 7 below.

         4.   BORROWER'S REPRESENTATIONS. The Borrower hereby represents,
warrants and covenants as follows:

              (a)   The Borrower has the full power, authority and legal right
to enter into this Agreement to be bound hereby and to perform and observe the
terms and conditions hereof, and is in compliance with all applicable material
laws, rules and regulations.

              (b)   This Agreement has been duly executed and delivered by the
Borrower and constitutes the legal, valid and binding obligation of the Borrower
enforceable against him in accordance with its terms, subject, as to the
enforcement of remedies, to applicable bankruptcy, reorganization, insolvency
and similar laws affecting creditors' rights generally and to moratorium laws
from time to time in effect and to general principles of equity.

              (c)   The execution, delivery and performance by the Borrower of
this Agreement does not and will not (i) violate or constitute a default under
any provision of any agreement, note or instrument which is binding upon the
Borrower or by which his properties are bound or materially affected, or any
law, rule or regulation, order writ, injunction or decree of any court or
governmental instrumentality or any contractual restriction binding on the
Borrower, or (ii) require any filing with or consent or other act by or in
respect of any governmental authority or other person or entity (other than the
filing of the appropriate number of UCC-1 financing statements covering the
Pledged Securities, if necessary, and any consent obtained by the Borrower prior
to the date hereof) or (iii) constitute a default thereunder or result in the
imposition or require the creation of any lien or charge (other than those
created, continued or otherwise contemplated hereby) upon the assets of the
Borrower.

              (d)   The Pledged Securities consist of not fewer than 60,000
shares of Common Stock of Dyax and are held and owned by the Borrower free and
clear of all liens, encumbrances, attachments, security interests, pledges and
charges, other than those in favor of Dyax.

                                     - 22 -
<PAGE>

         5.   BORROWER'S COVENANTS. The Borrower shall

              (a)   if the Collateral is in the form of a certificated security,
within the meaning of the Uniform Commercial Code, as adopted in the
Commonwealth of Massachusetts (the "Code"), surrender possession of the
Collateral to Dyax;

              (b)   if the Collateral is in the form of an uncertificated
security, within the meaning of the Code, cause Dyax to record this pledge in
the records of Dyax relating to the Pledged Securities;

              (c)   execute all such instruments, documents, and papers, and
will do all such acts as Dyax may reasonably request now and from time to time
hereafter with respect to the perfection of the security interest granted herein
and the assignment effected hereby, including without limitation making payments
of the proceeds of the Loan and such additional amounts as are necessary to
cause the current pledgee of the certificates for the Pledged Securities to
deliver such certificates to Dyax;

              (d)   keep the Collateral free and clear of all liens,
encumbrances, attachments, security interests, pledges, and charges, except in
favor of Dyax or created by Dyax;

              (e)   deliver to Dyax, if and when received by the Borrower, any
item representing or constituting any of the Collateral or, except as otherwise
provided herein, proceeds of Collateral;

              (f)   not cause or permit any of the Collateral presently
evidenced by a written certificate to be converted to uncertificated securities,
except on request of Dyax; and

              (g)   not exercise any right with respect to the Collateral which
would dilute or otherwise adversely affect Dyax's rights to the Collateral.

         6.   DEFAULT. Upon the occurrence of a Default, any and all Liabilities
of the Borrower to Dyax shall become immediately due and payable at the option
of Dyax and without further notice or demand, in addition to which Dyax may
exercise Dyax's rights and remedies upon Default, as set forth hereinafter. For
purposes of this Agreement, a "Default" under this Agreement shall mean any of
the following events: (i) an Event of Default under any Note, (ii) any
representation or warranty made by the Borrower in this Agreement being untrue
in any material respect when made, or (iii) failure of the Borrower to observe
or perform any other covenant, agreement or other term of this Agreement and the
continuation of such failure without it having been duly cured for a period of
thirty (30) days after written notice thereof given by Dyax to the Borrower.

         7.   EFFECT OF DEFAULT. Upon the occurrence of any Default, and at
any time thereafter, unless and until the Default may be cured, Dyax shall have
the right to apply the Collateral toward the satisfaction of the Liabilities, to
sell or otherwise dispose of the Collateral and/or enforce and collect the
Collateral for application towards (but not necessarily in complete

                                     - 23 -
<PAGE>

satisfaction) of the Liabilities, in addition to all of the rights and remedies
of a secured party upon default under the Code. The Borrower shall remain liable
to Dyax for any deficiency remaining following such application to any
Liabilities. Any and all shares of the Pledged Securities may be registered in
the name of Dyax or its nominee, and Dyax or its nominee may thereafter without
further notice exercise all voting and corporate rights at any meeting of any
issuer and exercise any and all rights of conversion, exchange, subscription or
any other rights, privileges or options pertaining to any shares of the Pledged
Securities as if it were the absolute owner thereof, including without
limitation, the right to exchange at its discretion any and all of the Pledged
Securities upon the merger, consolidation, reorganization, recapitalization or
other readjustment of any issuer or upon the exercise by any issuer or Dyax or
such nominee of any right, privilege or option pertaining to any shares of the
Pledged Securities, and, in connection therewith, to deposit and deliver any and
all of the Pledged Securities with any committee, depositary, transfer agent,
registrar or other designated agency upon such terms and conditions as it may
determine, all without liability except to account for property actually
received by it, but Dyax shall have no duty to exercise any of the aforesaid
rights, privileges or options and shall not be responsible for any failure to do
so or delay in so doing so long as it acts in good faith. The Borrower
acknowledges that any exercise by Dyax of Dyax's rights upon default may be
subject to compliance by Dyax with state and/or federal law governing the sale
of securities. Except as otherwise provided herein, the net proceeds which Dyax
shall receive from the sale of the Collateral, in accordance with the provisions
hereof, shall be applied in the following manner: First, to the payment of all
costs and expenses incurred by Dyax in connection with the administration and
enforcement of, or the preservation of any rights under, or otherwise in
connection with this Agreement (including, without limitation, the costs and
expenses of retaking, holding, preparing for sale or selling of any Collateral
and the reasonable fees and disbursements of its counsel and agents); Second, to
the payment of all other Liabilities in such order of priority as Dyax may
determine in its sole discretion; and Third, as otherwise provided by applicable
law.

         8.   PRIVATE PLACEMENTS.

              (a)   The Borrower recognizes that Dyax may be unable to effect a
public sale of any or all of the Pledged Securities by reason of certain
prohibitions contained in the federal securities laws and applicable state or
foreign securities law, but may resort to one or more private sales thereof to a
restricted group of purchasers who will be obliged to agree, among other things,
to acquire such securities for their own account for investment and not with a
view to the distribution or resale thereof. The Borrower acknowledges and agrees
that any such private sale may result in prices and other terms less favorable
to the seller than if such sale were a public sale and, notwithstanding such
circumstances, agrees that any such private sale shall be deemed to have been
made in a commercially reasonable manner. Dyax shall be under no obligation to
delay a sale of any of the Pledged Securities for the period of time necessary
to permit the issuer of such securities to register such securities for public
sale under the federal securities law, or under applicable state securities law,
even if the issuer would agree to do so.

              (b)   The Borrower further agrees to use commercially reasonable
efforts to do or cause to be done all such other acts and things (other than
effect the registration of the Pledged

                                     - 24 -
<PAGE>

Securities under applicable federal, state or foreign laws) as may be necessary
to make such sale or sales of any portion or all of the Pledged Securities valid
and binding and in compliance with any and all applicable laws, regulations,
orders, writs, injunctions, decrees or awards of any and all courts, arbitrators
or governmental instrumentalities, domestic or foreign, having jurisdiction over
any such sale or sales, all at the Borrower's expense. The Borrower further
agrees that a breach of any of the covenants contained in this Section 8 will
cause irreparable injury to Dyax, and that Dyax will have no adequate remedy at
law in respect of such breach and, as a consequence, agrees that each and every
covenant contained in this Section 8 shall be specifically enforceable against
the Borrower.

         9.   APPOINTMENT OF DYAX AS ATTORNEY-IN-FACT. In furtherance of the
remedies provided in Sections 7 and 8, the Borrower hereby designates Dyax as
and for the attorney-in-fact of the Borrower after the occurrence and during the
continuance of a Default to endorse in favor of Dyax any of the Collateral, to
cause the transfer of any of the Collateral in such name as Dyax may from time
to time determine, to cause the issuance of certificates for book entry and/or
uncertificated securities, and to make demand and to initiate actions to
accomplish the purposes of this Agreement. In connection with any action to
enforce any of the Collateral, Dyax may make such compromise or settlement with
respect to the Collateral as Dyax determines to be appropriate. After and during
the continuance of a Default, and in furtherance of the remedies provided in
Sections 7 and 8, Dyax shall also have and may exercise at any time all rights,
remedies, powers, and discretions of the Borrower with respect to and under the
Collateral. The within designation, being coupled with an interest, is
irrevocable until the within instrument is terminated by a written instrument
executed by a duly authorized officer of Dyax. Dyax shall not be liable for any
act or omission to act pursuant to this Paragraph except for any act or omission
to act which is in actual bad faith or which is grossly negligent.

         10.  CUMULATIVE REMEDIES. The rights, remedies, powers, privileges, and
discretions of Dyax hereunder (hereinafter, "Dyax's Rights And Remedies") shall
be cumulative and not exclusive of any rights or remedies which it otherwise may
have. No delay or omission by Dyax in exercising or enforcing any of Dyax's
Rights and Remedies shall operate as, or constitute, a waiver thereof. No waiver
by Dyax of any Default or of any default under any other agreement shall operate
as a waiver of any other default hereunder or under any other agreement. No
exercise of any of Dyax's Rights and Remedies and no other agreement or
transaction of whatever nature entered into between Dyax and the Borrower at any
time shall preclude any other exercise of Dyax's Rights and Remedies. No waiver
by Dyax of any of Dyax's Rights and Remedies on any one occasion shall be deemed
a waiver on any subsequent occasion, nor shall it be deemed a continuing waiver.
All of Dyax's Rights and Remedies and all of Dyax's rights, remedies, powers,
privileges, and discretions under any other agreement or transaction are
cumulative and not alternative or exclusive and may be exercised by Dyax at such
time or times and in such order of preference as Dyax in its sole discretion may
determine.

         11.  DEFINITION OF LIABILITIES. "Liabilities" shall mean (i) all
indebtedness, obligations and liabilities of the Borrower, whether of principal,
interest, fees, expenses or otherwise, now existing or hereafter contracted or
incurred under or in connection with the Loan and any and all extensions,
renewals, refinancings and refunding of any such indebtedness in

                                     - 25 -
<PAGE>

whole or in part, (ii) all costs and expenses incurred by Dyax in the collection
of any of such Borrower indebtedness, including without limitation reasonable
attorneys' fees and legal expenses, and (iii) all future advances made by Dyax
for the protection or preservation of the Collateral or any portion thereof.

         12.  WAIVERS BY BORROWER. The Borrower

              (a)   waives presentment, demand, notice, and protest with respect
to the Liabilities and the Collateral; and

              (b)   waives any delay on the part of Dyax; and

              (c)   assents to any indulgence or waiver which Dyax may grant or
give to the Borrower or any other person liable or obliged to Dyax for or on the
Liabilities; and

              (d)   agrees that no release of any property securing the
Liabilities shall affect the rights of Dyax with respect to the Collateral
hereunder; and

              (e)   if entitled thereto, waives the right to notice and/or
hearing prior to Dyax's exercising of Dyax's rights and remedies hereunder upon
default.

         13.  PARTIAL RELEASE UPON PAY-DOWN OF THE NOTE. Upon written notice
from the Borrower that he wishes to sell some or all of the Pledged Securities
and apply the proceeds of such sale to amounts due under the Note, Dyax agrees
to deliver promptly to a broker designated by the Borrower and reasonably
satisfactory to Dyax certificates representing such Pledged Securities, provided
that such instructions include or are accompanied by irrevocable instruction
from the Borrower (with signature guarantee) to the broker requiring that the
net proceeds from the sale of such Pledged Securities be delivered by check
payable to Dyax and that a certificate for any shares of the Pledged Securities
remaining unsold be returned to Dyax.

         14.  DUTIES OF DYAX. Dyax shall have no duty as to the collection or
protection of the Collateral or any income or distribution thereon, beyond the
safe custody of such of the Collateral as may come into the possession of Dyax
and shall have no duty as to the preservation of rights against prior parties or
any other rights pertaining thereto. Dyax's Rights and Remedies may be exercised
without resort or regard to any other source of satisfaction of the Liabilities.

         15.  BINDING AGREEMENT. This Agreement shall be binding upon the
Borrower and upon the Borrower's representatives, successors, and assigns, and
shall enure to the benefit of Dyax and its successors and assigns.

         16.  COMPLETE AGREEMENT. This Agreement and all other instruments
executed in connection herewith incorporate all discussions and negotiations
among Dyax and the Borrower concerning the matters included herein and in such
other instruments.  No such discussions or negotiations shall limit, modify, or
otherwise affect the provisions hereof.  No modification,

                                     - 26 -
<PAGE>

amendment, or waiver of any provision of this Agreement shall be effective
unless executed in writing by the party to be charged with such modification,
amendment and waiver, and if such party be Dyax, then by a duly authorized
officer thereof other than the Borrower.

         17.  USE OF ORIGINALS. This Agreement and all other documents in Dyax's
possession which relate to the Liabilities may be reproduced by Dyax by any
photographic, photostatic, microfilm, micro-card, miniature photographic,
xerographic, or similar process, and, with the exception of instruments
constituting the Collateral, Dyax may destroy the original from which any
document was so reproduced. Any such reproduction shall be admissible in
evidence as the original itself in any judicial or administrative proceeding
(whether or not the original is an existence and whether or not such
reproduction was made in the regular course of business) and any enlargement,
facsimile, or further reproduction shall likewise be admissible in evidence.

         18.  NOTICES. All notices, requests, demands and other communications
to be given pursuant to this Agreement shall be in writing and shall be deemed
to have been duly given if delivered by hand or overnight courier or mailed by
registered or certified mail, return receipt requested, postage prepaid,
addressed to the party to receive notice at its or his respective address set
forth in the first paragraph of this Agreement or such other address as such
party shall have designated by notice in writing to the other party in
accordance with this section.

         19.  GOVERNING LAW. This Agreement, and all rights and obligations
hereunder, including matters of construction, validity, and performance, shall
be governed by the laws of the Commonwealth of Massachusetts. The Borrower
submits to the jurisdiction of the courts of said Commonwealth for all purposes
with respect to this Agreement and the Borrower's relationships with Dyax.

         20.  SEALED INSTRUMENT. It is intended that this Agreement take effect
as a sealed instrument.

                                     - 27 -
<PAGE>

         IN WITNESS WHEREOF, the undersigned has executed the foregoing Pledge
Agreement as of the date first above written.

                                          -------------------------------
                                          Robert A. Dishman, individually

                                     - 28 -
<PAGE>

                                                                   EXHIBIT C-2

                                PLEDGE AGREEMENT

         THIS PLEDGE AGREEMENT (this "Agreement") dated as of February 18, 1998
is made by Robert A. Dishman (the "Borrower"), residing at 37 Garland Road,
Concord, Massachusetts 01742, in favor of Dyax Corp. ("Dyax"), a Delaware
corporation with its principal place of business at One Kendall Square, Building
600, Cambridge, Massachusetts 02139.

                                    RECITALS

         (a)  Dyax has agreed to make a $360,000 loan (the "Loan") to the
Borrower on or after the date hereof evidenced by a promissory note of the
Borrower in the original principal amount of $360,000 (the "Note").

         (b)  Dyax is willing to make the Loan upon the condition, among
others, that the Borrower enter into this Agreement to secure the Liabilities
(as defined in Section 11 hereof).

         NOW, THEREFORE, for and in consideration of the premises and the Loan
made by Dyax and other good and valuable consideration, the receipt of which is
hereby acknowledged, and intending to be legally bound hereby, the Borrower
represents, warrants, covenants and agrees as follows:

         1.   PLEDGE. To secure the prompt, punctual, and faithful performance
of all and each of the present and future Liabilities of the Borrower to Dyax,
the Borrower hereby grants to Dyax, a security interest in and to, and assigns,
pledges, and delivers to Dyax certificates representing certain shares of the
Common Stock of Dyax issued to the Borrower as of the date hereof or issuable to
the Borrower hereafter ("Pledged Securities"), together with appropriate undated
stock powers duly executed in blank, and all products, proceeds, substitutions,
additions, interest, dividends, and other distributions in respect thereto, as
described in Section 2 below (all of which are referred to hereinafter as the
"Collateral").

         2.   STOCK DIVIDENDS, DISTRIBUTIONS, ETC. If, while this Agreement is
in effect, the Borrower shall become entitled to receive or shall receive any
stock certificate (including, without limitation, any certificate representing a
stock dividend or a distribution in connection with any reclassification,
increase or reduction of capital, or issued in connection with any
reorganization), whether as an addition to, in substitution of or in exchange
for any shares of any Pledged Securities, or otherwise, the Borrower agrees to
accept the same as agent for Dyax and to hold the same in trust on behalf of and
for the benefit of Dyax and to deliver the same forthwith to Dyax in the exact
form received, with the indorsement of the Borrower when necessary and/or with
appropriate undated stock powers duly executed in blank, to be held by Dyax as
part of the Collateral. In case any distribution of capital shall be made on or
in respect of the Pledged Securities or any property shall be distributed upon
or with respect to the Pledged Securities pursuant to the recapitalization or
reclassification of the capital of Dyax or pursuant

                                     - 29 -
<PAGE>

to the reorganization thereof, the property so distributed shall be delivered to
Dyax as Collateral. All sums of money and property so paid or distributed in
respect of the Pledged Securities which are received by the Borrower shall,
until paid or delivered to Dyax, be held by the Borrower in trust as Collateral.

         3.   CASH DIVIDENDS; VOTING RIGHTS. Unless a Default (as defined in
Section 6) has occurred and is continuing, the Borrower shall be entitled to
receive all cash dividends paid in respect of the Pledged Securities, to vote
the Pledged Securities and to give consents, waivers and ratifications, and to
take other action in respect of the Pledged Securities. After the occurrence and
during the continuance of any Default, Dyax shall have the right, upon notice to
the Borrower, to receive all cash dividends paid in respect of the Pledged
Securities and to exercise voting rights as specified in Section 7 below.

         4.   BORROWER'S REPRESENTATIONS.  The Borrower hereby represents,
warrants and covenants as follows:

              (a)   The Borrower has the full power, authority and legal right
to enter into this Agreement to be bound hereby and to perform and observe the
terms and conditions hereof, and is in compliance with all applicable material
laws, rules and regulations.

              (b)   This Agreement has been duly executed and delivered by the
Borrower and constitutes the legal, valid and binding obligation of the Borrower
enforceable against him in accordance with its terms, subject, as to the
enforcement of remedies, to applicable bankruptcy, reorganization, insolvency
and similar laws affecting creditors' rights generally and to moratorium laws
from time to time in effect and to general principles of equity.

              (c)   The execution, delivery and performance by the Borrower of
this Agreement does not and will not (i) violate or constitute a default under
any provision of any agreement, note or instrument which is binding upon the
Borrower or by which his properties are bound or materially affected, or any
law, rule or regulation, order writ, injunction or decree of any court or
governmental instrumentality or any contractual restriction binding on the
Borrower, or (ii) require any filing with or consent or other act by or in
respect of any governmental authority or other person or entity (other than the
filing of the appropriate number of UCC-1 financing statements covering the
Pledged Securities, if necessary, and any consent obtained by the Borrower prior
to the date hereof) or (iii) constitute a default thereunder or result in the
imposition or require the creation of any lien or charge (other than those
created, continued or otherwise contemplated hereby) upon the assets of the
Borrower.

              (d)   The Pledged Securities consist of not fewer than 120,000
shares of Common Stock of Dyax and are held and owned by the Borrower free and
clear of all liens, encumbrances, attachments, security interests, pledges and
charges, other than those in favor of Dyax.

                                     - 30 -
<PAGE>

         5.   BORROWER'S COVENANTS. The Borrower shall

              (a)   if the Collateral is in the form of a certificated security,
within the meaning of the Uniform Commercial Code, as adopted in the
Commonwealth of Massachusetts (the "Code"), surrender possession of the
Collateral to Dyax;

              (b)   if the Collateral is in the form of an uncertificated
security, within the meaning of the Code, cause Dyax to record this pledge in
the records of Dyax relating to the Pledged Securities;

              (c)   execute all such instruments, documents, and papers, and
will do all such acts as Dyax may reasonably request now and from time to time
hereafter with respect to the perfection of the security interest granted herein
and the assignment effected hereby, including without limitation making payments
of the proceeds of the Loan and such additional amounts as are necessary to
cause the current pledgee of the certificates for the Pledged Securities to
deliver such certificates to Dyax;

              (d)   keep the Collateral free and clear of all liens,
encumbrances, attachments, security interests, pledges, and charges, except in
favor of Dyax or created by Dyax;

              (e)   deliver to Dyax, if and when received by the Borrower, any
item representing or constituting any of the Collateral or, except as otherwise
provided herein, proceeds of Collateral;

              (f)   not cause or permit any of the Collateral presently
evidenced by a written certificate to be converted to uncertificated securities,
except on request of Dyax; and

              (g)   not exercise any right with respect to the Collateral which
would dilute or otherwise adversely affect Dyax's rights to the Collateral.

         6.   DEFAULT. Upon the occurrence of a Default, any and all Liabilities
of the Borrower to Dyax shall become immediately due and payable at the option
of Dyax and without further notice or demand, in addition to which Dyax may
exercise Dyax's rights and remedies upon Default, as set forth hereinafter. For
purposes of this Agreement, a "Default" under this Agreement shall mean any of
the following events: (i) an Event of Default under any Note, (ii) any
representation or warranty made by the Borrower in this Agreement being untrue
in any material respect when made, or (iii) failure of the Borrower to observe
or perform any other covenant, agreement or other term of this Agreement and the
continuation of such failure without it having been duly cured for a period of
thirty (30) days after written notice thereof given by Dyax to the Borrower.

         7.   EFFECT OF DEFAULT. Upon the occurrence of any Default, and at any
time thereafter, unless and until the Default may be cured, Dyax shall have the
right to apply the Collateral toward the satisfaction of the Liabilities, which
application shall be done in accordance

                                     - 31 -
<PAGE>

with Section 2.5.2 of the Executive Employment Agreement of even date between
the Borrower and Dyax with respect to any Unvested Shares (as defined in such
agreement), to sell or otherwise dispose of the Collateral and/or enforce and
collect the Collateral for application towards (but not necessarily in complete
satisfaction) of the Liabilities, in addition to all of the rights and remedies
of a secured party upon default under the Code. The Borrower shall remain liable
to Dyax for any deficiency remaining following such application to any
Liabilities. Any and all shares of the Pledged Securities may be registered in
the name of Dyax or its nominee, and Dyax or its nominee may thereafter without
further notice exercise all voting and corporate rights at any meeting of any
issuer and exercise any and all rights of conversion, exchange, subscription or
any other rights, privileges or options pertaining to any shares of the Pledged
Securities as if it were the absolute owner thereof, including without
limitation, the right to exchange at its discretion any and all of the Pledged
Securities upon the merger, consolidation, reorganization, recapitalization or
other readjustment of any issuer or upon the exercise by any issuer or Dyax or
such nominee of any right, privilege or option pertaining to any shares of the
Pledged Securities, and, in connection therewith, to deposit and deliver any and
all of the Pledged Securities with any committee, depositary, transfer agent,
registrar or other designated agency upon such terms and conditions as it may
determine, all without liability except to account for property actually
received by it, but Dyax shall have no duty to exercise any of the aforesaid
rights, privileges or options and shall not be responsible for any failure to do
so or delay in so doing so long as it acts in good faith. The Borrower
acknowledges that any exercise by Dyax of Dyax's rights upon default may be
subject to compliance by Dyax with state and/or federal law governing the sale
of securities. Except as otherwise provided herein, the net proceeds which Dyax
shall receive from the sale of the Collateral, in accordance with the provisions
hereof, shall be applied in the following manner: First, to the payment of all
costs and expenses incurred by Dyax in connection with the administration and
enforcement of, or the preservation of any rights under, or otherwise in
connection with this Agreement (including, without limitation, the costs and
expenses of retaking, holding, preparing for sale or selling of any Collateral
and the reasonable fees and disbursements of its counsel and agents); Second, to
the payment of all other Liabilities in such order of priority as Dyax may
determine in its sole discretion; and Third, as otherwise provided by applicable
law.

         8.   PRIVATE PLACEMENTS.

         (a)  The Borrower recognizes that Dyax may be unable to effect a public
sale of any or all of the Pledged Securities by reason of certain prohibitions
contained in the federal securities laws and applicable state or foreign
securities law, but may resort to one or more private sales thereof to a
restricted group of purchasers who will be obliged to agree, among other things,
to acquire such securities for their own account for investment and not with a
view to the distribution or resale thereof. The Borrower acknowledges and agrees
that any such private sale may result in prices and other terms less favorable
to the seller than if such sale were a public sale and, notwithstanding such
circumstances, agrees that any such private sale shall be deemed to have been
made in a commercially reasonable manner. Dyax shall be under no obligation to
delay a sale of any of the Pledged Securities for the period of time necessary
to permit the issuer of such securities to register such securities for public
sale under the federal securities law, or under applicable state securities law,
even if the issuer would agree to do so.

                                     - 32 -
<PAGE>

         (b)  The Borrower further agrees to use commercially reasonable efforts
to do or cause to be done all such other acts and things (other than effect the
registration of the Pledged Securities under applicable federal, state or
foreign laws) as may be necessary to make such sale or sales of any portion or
all of the Pledged Securities valid and binding and in compliance with any and
all applicable laws, regulations, orders, writs, injunctions, decrees or awards
of any and all courts, arbitrators or governmental instrumentalities, domestic
or foreign, having jurisdiction over any such sale or sales, all at the
Borrower's expense. The Borrower further agrees that a breach of any of the
covenants contained in this Section 8 will cause irreparable injury to Dyax, and
that Dyax will have no adequate remedy at law in respect of such breach and, as
a consequence, agrees that each and every covenant contained in this Section 8
shall be specifically enforceable against the Borrower.

         9.   APPOINTMENT OF DYAX AS ATTORNEY-IN-FACT. In furtherance of the
remedies provided in Sections 7 and 8, the Borrower hereby designates Dyax as
and for the attorney-in-fact of the Borrower after the occurrence and during the
continuance of a Default to endorse in favor of Dyax any of the Collateral, to
cause the transfer of any of the Collateral in such name as Dyax may from time
to time determine, to cause the issuance of certificates for book entry and/or
uncertificated securities, and to make demand and to initiate actions to
accomplish the purposes of this Agreement. In connection with any action to
enforce any of the Collateral, Dyax may make such compromise or settlement with
respect to the Collateral as Dyax determines to be appropriate. After and during
the continuance of a Default, and in furtherance of the remedies provided in
Sections 7 and 8, Dyax shall also have and may exercise at any time all rights,
remedies, powers, and discretions of the Borrower with respect to and under the
Collateral. The within designation, being coupled with an interest, is
irrevocable until the within instrument is terminated by a written instrument
executed by a duly authorized officer of Dyax. Dyax shall not be liable for any
act or omission to act pursuant to this Paragraph except for any act or omission
to act which is in actual bad faith or which is grossly negligent.

         10.  CUMULATIVE REMEDIES. The rights, remedies, powers, privileges, and
discretions of Dyax hereunder (hereinafter, "Dyax's Rights And Remedies") shall
be cumulative and not exclusive of any rights or remedies which it otherwise may
have. No delay or omission by Dyax in exercising or enforcing any of Dyax's
Rights and Remedies shall operate as, or constitute, a waiver thereof. No waiver
by Dyax of any Default or of any default under any other agreement shall operate
as a waiver of any other default hereunder or under any other agreement. No
exercise of any of Dyax's Rights and Remedies and no other agreement or
transaction of whatever nature entered into between Dyax and the Borrower at any
time shall preclude any other exercise of Dyax's Rights and Remedies. No waiver
by Dyax of any of Dyax's Rights and Remedies on any one occasion shall be deemed
a waiver on any subsequent occasion, nor shall it be deemed a continuing waiver.
All of Dyax's Rights and Remedies and all of Dyax's rights, remedies, powers,
privileges, and discretions under any other agreement or transaction are
cumulative and not alternative or exclusive and may be exercised by Dyax at such
time or times and in such order of preference as Dyax in its sole discretion may
determine.

         11.  DEFINITION OF LIABILITIES. "Liabilities" shall mean (i) all
indebtedness, obligations and liabilities of the Borrower, whether of principal,
interest, fees, expenses or

                                     - 33 -
<PAGE>

otherwise, now existing or hereafter contracted or incurred under or in
connection with the Loan and any and all extensions, renewals, refinancings and
refunding of any such indebtedness in whole or in part, (ii) all costs and
expenses incurred by Dyax in the collection of any of such Borrower
indebtedness, including without limitation reasonable attorneys' fees and legal
expenses, and (iii) all future advances made by Dyax for the protection or
preservation of the Collateral or any portion thereof.

         12.  WAIVERS BY BORROWER. The Borrower

              (a)  waives presentment, demand, notice, and protest with respect
to the Liabilities and the Collateral; and

              (b)  waives any delay on the part of Dyax; and

              (c)  assents to any indulgence or waiver which Dyax may grant or
give to the Borrower or any other person liable or obliged to Dyax for or on the
Liabilities; and

              (d)  agrees that no release of any property securing the
Liabilities shall affect the rights of Dyax with respect to the Collateral
hereunder; and

              (e)  if entitled thereto, waives the right to notice and/or
hearing prior to Dyax's exercising of Dyax's rights and remedies hereunder upon
default.

         13.  PARTIAL RELEASE UPON PAY-DOWN OF THE NOTE. Upon written notice
from the Borrower that he wishes to sell some or all of the Pledged Securities
and apply the proceeds of such sale to amounts due under the Note, Dyax agrees
to deliver promptly to a broker designated by the Borrower and reasonably
satisfactory to Dyax certificates representing such Pledged Securities, provided
that such instructions include or are accompanied by irrevocable instruction
from the Borrower (with signature guarantee) to the broker requiring that the
net proceeds from the sale of such Pledged Securities be delivered by check
payable to Dyax and that a certificate for any shares of the Pledged Securities
remaining unsold be returned to Dyax.

         14.  DUTIES OF DYAX. Dyax shall have no duty as to the collection or
protection of the Collateral or any income or distribution thereon, beyond the
safe custody of such of the Collateral as may come into the possession of Dyax
and shall have no duty as to the preservation of rights against prior parties or
any other rights pertaining thereto. Dyax's Rights and Remedies may be exercised
without resort or regard to any other source of satisfaction of the Liabilities.

         15.  BINDING AGREEMENT. This Agreement shall be binding upon the
Borrower and upon the Borrower's representatives, successors, and assigns, and
shall enure to the benefit of Dyax and its successors and assigns.

         16.  COMPLETE AGREEMENT. This Agreement and all other instruments
executed in connection herewith incorporate all discussions and negotiations
among Dyax and the Borrower

                                     - 34 -
<PAGE>

concerning the matters included herein and in such other instruments. No such
discussions or negotiations shall limit, modify, or otherwise affect the
provisions hereof. No modification, amendment, or waiver of any provision of
this Agreement shall be effective unless executed in writing by the party to be
charged with such modification, amendment and waiver, and if such party be Dyax,
then by a duly authorized officer thereof other than the Borrower.

         17.  USE OF ORIGINALS. This Agreement and all other documents in Dyax's
possession which relate to the Liabilities may be reproduced by Dyax by any
photographic, photostatic, microfilm, micro-card, miniature photographic,
xerographic, or similar process, and, with the exception of instruments
constituting the Collateral, Dyax may destroy the original from which any
document was so reproduced. Any such reproduction shall be admissible in
evidence as the original itself in any judicial or administrative proceeding
(whether or not the original is an existence and whether or not such
reproduction was made in the regular course of business) and any enlargement,
facsimile, or further reproduction shall likewise be admissible in evidence.

         18.  NOTICES. All notices, requests, demands and other communications
to be given pursuant to this Agreement shall be in writing and shall be deemed
to have been duly given if delivered by hand or overnight courier or mailed by
registered or certified mail, return receipt requested, postage prepaid,
addressed to the party to receive notice at its or his respective address set
forth in the first paragraph of this Agreement or such other address as such
party shall have designated by notice in writing to the other party in
accordance with this section.

         19.  GOVERNING LAW. This Agreement, and all rights and obligations
hereunder, including matters of construction, validity, and performance, shall
be governed by the laws of the Commonwealth of Massachusetts. The Borrower
submits to the jurisdiction of the courts of said Commonwealth for all purposes
with respect to this Agreement and the Borrower's relationships with Dyax.

        20.  SEALED INSTRUMENT. It is intended that this Agreement take effect
as a sealed instrument.

                                     - 35 -
<PAGE>

         IN WITNESS WHEREOF, the undersigned has executed the foregoing Pledge
Agreement as of the date first above written.

                                   -------------------------------
                                   Robert A. Dishman, individually

                                     - 36 -

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00010-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00010-of-00352.parquet"}]]