<Page>
                                  SCHEDULE 14A
                                 (RULE 14A-101)
                    INFORMATION REQUIRED IN PROXY STATEMENT

                            SCHEDULE 14A INFORMATION

                  PROXY STATEMENT PURSUANT TO SECTION 14(A) OF
            THE SECURITIES EXCHANGE ACT OF 1934 (AMENDMENT NO.    )

<Table>
              
      Filed by the Registrant /X/
      Filed by a Party other than the Registrant / /

      Check the appropriate box:
      / /        Preliminary Proxy Statement
      / /        CONFIDENTIAL, FOR USE OF THE COMMISSION ONLY (AS PERMITTED
                 BY RULE 14a-6(e)(2))
      /X/        Definitive Proxy Statement
      / /        Definitive Additional Materials
      / /        Soliciting Material Pursuant to Section240.14a-12

                                                DYAX CORP.
      -----------------------------------------------------------------------
                 (Name of Registrant as Specified In Its Charter)

      -----------------------------------------------------------------------
           (Name of Person(s) Filing Proxy Statement, if other than the
                                    Registrant)
</Table>

Payment of Filing Fee (Check the appropriate box):

<Table>
          
/X/        No fee required.
/ /        Fee computed on table below per Exchange Act Rules 14a-6(i)(4)
           and 0-11.
           (1)  Title of each class of securities to which transaction
                applies:
                ----------------------------------------------------------
           (2)  Aggregate number of securities to which transaction
                applies:
                ----------------------------------------------------------
           (3)  Per unit price or other underlying value of transaction
                computed pursuant to Exchange Act Rule 0-11 (set forth the
                amount on which the filing fee is calculated and state how
                it was determined):
                ----------------------------------------------------------
           (4)  Proposed maximum aggregate value of transaction:
                ----------------------------------------------------------
           (5)  Total fee paid:
                ----------------------------------------------------------

/ /        Fee paid previously with preliminary materials.

/ /        Check box if any part of the fee is offset as provided by
           Exchange Act Rule 0-11(a)(2) and identify the filing for which
           the offsetting fee was paid previously. Identify the previous
           filing by registration statement number, or the Form or
           Schedule and the date of its filing.

           (1)  Amount Previously Paid:
                ----------------------------------------------------------
           (2)  Form, Schedule or Registration Statement No.:
                ----------------------------------------------------------
           (3)  Filing Party:
                ----------------------------------------------------------
           (4)  Date Filed:
                ----------------------------------------------------------
</Table>
<Page>
                                   DYAX CORP.
                             300 TECHNOLOGY SQUARE
                              CAMBRIDGE, MA 02139
                                 (617) 250-5500

                    NOTICE OF ANNUAL MEETING OF STOCKHOLDERS
                            TO BE HELD MAY 16, 2002

    The 2002 Annual Meeting of Stockholders of Dyax Corp., a Delaware
corporation ("Dyax"), will be held at the offices of Dyax Corp., 300 Technology
Square, Cambridge, Massachusetts, at 2:00 p.m. on Thursday, May 16, 2002, for
the following purposes:

    1.  To elect three Class II directors to serve until the 2005 Annual Meeting
       of Stockholders.

    2.  To vote on a proposed amendment to Dyax's Amended and Restated 1995
       Equity Incentive Plan (the "1995 Equity Plan") to, among other things,
       increase the number of shares issued and issuable under the plan.

    3.  To vote on a proposed amendment to Dyax's 1998 Employee Stock Purchase
       Plan (the "Purchase Plan") that would increase the number of shares of
       Common Stock issued and issuable under the plan.

    4.  To transact any other business that may properly come before the meeting
       or any adjournment of the meeting.

    Only stockholders of record at the close of business on April 3, 2002 will
be entitled to vote at the meeting or any adjournment of the meeting.

    It is important that your shares be represented at the meeting. THEREFORE,
WHETHER OR NOT YOU PLAN TO ATTEND THE MEETING, PLEASE COMPLETE YOUR PROXY AND
RETURN IT IN THE ENCLOSED ENVELOPE, which requires no postage if mailed in the
United States. If you attend the meeting and wish to vote in person, your proxy
will not be used.

                                          By order of the Board of Directors,
                                          Nathaniel S. Gardiner
                                          Secretary

April 22, 2002
<Page>
                                   DYAX CORP.

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

                                PROXY STATEMENT
                       FOR ANNUAL MEETING OF STOCKHOLDERS
                                   TO BE HELD
                                  MAY 16, 2002

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

    Our board of directors is soliciting your proxy with the enclosed proxy card
for use at the 2002 Annual Meeting of Stockholders of Dyax Corp. to be held at
our offices at 300 Technology Square, Cambridge, Massachusetts at 2:00 p.m. on
Thursday, May 16, 2002, and at any adjournments of the meeting. The approximate
date on which this proxy statement and accompanying proxy are first being sent
or given to stockholders is April 22, 2002.

GENERAL INFORMATION ABOUT VOTING

    WHO CAN VOTE.  You will be entitled to vote your shares of Dyax Common Stock
at the annual meeting if you were a stockholder of record at the close of
business on April 3, 2002. As of that date, 19,614,486 shares of Common Stock
were outstanding. You are entitled to one vote for each share of Common Stock
that you held at that date.

    HOW TO VOTE YOUR SHARES.  You can vote your shares either by attending the
annual meeting and voting in person or by voting by proxy. If you choose to vote
by proxy, please complete, sign, date and return the enclosed proxy card. The
proxies named in the enclosed proxy card will vote your shares as you have
instructed. If you sign and return the proxy card without indicating how you
wish your shares to be voted, the proxies will vote your shares in favor of the
proposals contained in this proxy statement, as recommended by our board of
directors. Even if you plan to attend the meeting, please complete and mail your
proxy card to ensure that your shares are represented at the meeting. If you
attend the meeting, you can still revoke your proxy by voting in person.

    HOW YOU MAY REVOKE YOUR PROXY.  You may revoke the authority granted by your
executed proxy at any time before its exercise by filing with Dyax, Attention:
Nathaniel S. Gardiner, Secretary, a written revocation or a duly executed proxy
bearing a later date, or by voting in person at the meeting.

    QUORUM.  A quorum of stockholders is required in order to transact business
at the annual meeting. A majority of the outstanding shares of Common Stock
entitled to vote must be present at the meeting, represented either in person or
by proxy, to constitute a quorum for the transaction of business. If your shares
are held in a brokerage account, you must make arrangements with your broker or
bank to vote your shares in person or to revoke your proxy.

    ABSTENTIONS AND BROKER NON-VOTES.  "Broker non-votes" are proxies submitted
by brokers that do not indicate a vote for one or more proposals because the
brokers do not have discretionary voting authority and have not received
instructions from the beneficial owners on how to vote on these proposals.
Abstentions and broker non-votes will be considered present for purposes of
determining a quorum for the transaction of business.

                                       1
<Page>
SHARE OWNERSHIP

    The following table and footnotes set forth certain information regarding
the beneficial ownership of our Common Stock as of March 1, 2002 by (i) persons
known by us to be beneficial owners of more than 5% of our Common Stock,
(ii) our current executive officers and our named executive officers, (iii) our
directors and (iv) all our current executive officers and directors as a group.

<Table>
<Caption>
                                                                NUMBER OF SHARES
                                                               BENEFICIALLY OWNED
                                                              ---------------------
BENEFICIAL OWNER                                              SHARES (1)   PERCENT
- ----------------                                              ----------   --------
                                                                     
HealthCare Ventures V, L.P. and certain related entities      1,651,376      8.44%
(2).........................................................
  44 Nassau Street
  Princeton, NJ 08542

Alta Partners and certain related entities (3)..............  1,336,147      6.83%
  One Embarcadero Center, Suite 4050
  San Francisco, CA 94111

Deutsche Bank A.G. and Deutsche Asset Management Europe GmbH  1,180,000      6.03%
(4).........................................................
  Taunusanlage 12
  60325, Frankfurt
  Federal Republic of Germany

Henry E. Blair (5)..........................................    797,380      4.07%
Gregory D. Phelps (6).......................................    204,209      1.04%
Constantine Anagnostopoulos (7).............................     45,020         *
James W. Fordyce (8)........................................    689,246      3.52%
Thomas L. Kempner (9).......................................    289,501      1.48%
Henry R. Lewis (10).........................................     74,782         *
John W. Littlechild (11)....................................  1,671,376      8.54%
Alix Marduel (12)...........................................  1,363,022      6.96%
David J. McLachlan (13).....................................     27,075         *
Scott C. Chappel (14).......................................    106,020         *
Stephen S. Galliker (15)....................................    161,080         *
Jack H. Morgan (16).........................................     18,609         *
David B. Patteson (17)......................................     68,726         *
All Current Directors and Executive Officers as a Group (13   5,516,046     28.18%
Persons) (18)...............................................
</Table>

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

*   Less than 1%

(1) The persons and entities named in the table have sole voting and investment
    power with respect to all shares beneficially owned by them, except as noted
    below.

(2) Based on the Schedule 13G filed by HealthCare Ventures V, L.P. with the SEC
    on February 11, 2002, HealthCare Partners V, L.P. is the general partner of
    HeatlhCare Ventures V, L.P. The natural persons who control the 1,651,376
    shares owned by HealthCare Ventures V., L.P. are John W. Littlechild,
    William Crouse, Harold R. Werner, Christopher Mirabelli, Ph.D., Augustine
    Lawlor, and James H. Cavanaugh, Ph.D.

(3) Based on the Schedule 13G filed by Alta Partners with the SEC on
    February 5, 2002, consists of (i) 830,530 shares held by Alta BioPharma
    Partners, L.P., (ii) 31,305 shares held by Alta Embarcadero BioPharma
    Partners, LLC, and (iii) 474,312 shares held by Dyax Chase Partners, LLC. As
    general partners and managing members of these entities, the principals of
    Alta Partners exercise control over voting and investment decisions with
    respect to these shares. The principals of Alta Partners are Jean Deleage,
    Garrett Gruener, Dan Janney, Alix Marduel and Guy Nohra.

                                       2
<Page>
(4) Based on the Schedule 13G filed by Deutsche Bank AG with the SEC on
    February 14, 2002, consists of (i) 180,000 shares owned by Deutsche Bank
    A.G. and Deutsche Asset Management Europe GmbH, and (ii) 1,000,000 shares
    owned by DWS Investment GmbH. Deutsche Bank A.G. and Deutsche Asset
    Management Europe GmbH share voting power with respect to all 1,180,000
    shares. DWS Investment GmbH shares voting power with respect to 1,000,000
    shares.

(5) Includes (i) 114,100 shares which are held in trust for the benefit of
    Mr. Blair's spouse and child, as to which Mr. Blair disclaims beneficial
    ownership, and (ii) 126,259 shares of Common Stock issuable to Mr. Blair
    upon exercise of outstanding options exercisable within the 60-day period
    following March 1, 2002.

(6) Includes 134,896 shares of Common Stock issuable to Mr. Phelps upon exercise
    of outstanding options exercisable within the 60-day period following
    March 1, 2002.

(7) Includes 31,435 shares of Common Stock issuable to Dr. Anagnostopoulos upon
    exercise of outstanding options exercisable within the 60-day period
    following March 1, 2002.

(8) Includes 648,031 shares held by Prince Venture Partners IV Limited
    Partnership. Mr. Fordyce is a general partner of Prince Ventures Limited
    Partnership, the general partner of Prince Venture Partners IV Limited
    Partnership. Mr. Fordyce disclaims beneficial ownership of these shares,
    except to the extent of his pecuniary interest in these entities. Also
    includes 22,674 shares of Common Stock issuable to Mr. Fordyce upon exercise
    of outstanding options exercisable within the 60-day period following
    March 1, 2002.

(9) Includes (i) 230,543 shares of Common Stock held in trust for the benefit of
    Mr. Kempner's brother, Mr. Kempner's brother's children, Mr. Kempner's
    children and Mr. Kempner, and (ii) 11,792 shares held by Pinpoint Partners
    Corporation, of which Mr. Kempner is President. Also includes 31,938 shares
    of Common Stock issuable to Mr. Kempner upon exercise of outstanding options
    exercisable within the 60-day period following March 1, 2002.

(10) Includes 34,424 shares of Common Stock issuable to Dr. Lewis upon exercise
    of outstanding options exercisable within the 60-day period following
    March 1, 2002.

(11) Includes 1,651,376 shares held by HealthCare Ventures V, L.P.
    Mr. Littlechild is the general partner of HealthCare Partners, LP, which is
    the general partner of HealthCare Ventures V, L.P. Mr. Littlechild disclaims
    beneficial ownership of these shares except to the extent of his pecuniary
    interest in the limited partnerships. Also includes 20,000 shares of Common
    Stock issuable to Mr. Littlechild upon exercise of outstanding options
    exercisable within the 60-day period following March 1, 2002.

(12) Includes (i) 830,530 shares held by Alta BioPharma Partners, L.P.,
    (ii) 31,305 shares held by Alta Embarcadero BioPharma Partners, LLC, and
    (iii) 474,312 shares held by Dyax Chase Partners, LLC. The principals of
    Alta Partners exercise control over voting and investment decisions with
    respect to these securities. See Note (3) above. Dr. Marduel is a general
    partner of Alta Partners. She disclaims beneficial ownership of these
    shares, except to the extent of her pecuniary interest in the entities. Also
    includes 26,875 shares of Common Stock issuable to Dr. Marduel upon exercise
    of outstanding options exercisable within the 60-day period following
    March 1, 2002.

(13) Includes 21,875 shares of Common Stock issuable to Mr. McLachlan upon
    exercise of outstanding options exercisable within the 60-day period
    following March 1, 2002.

(14) Includes 69,079 shares of Common Stock issuable to Dr. Chappel upon
    exercise of outstanding options exercisable within the 60-day period
    following March 1, 2002.

(15) Includes 112,938 shares of Common Stock issuable to Mr. Galliker upon
    exercise of outstanding options exercisable within the 60-day period
    following March 1, 2002.

                                       3
<Page>
(16) Includes 18,020 shares of Common Stock issuable to Mr. Morgan upon exercise
    of outstanding options exercisable within the 60-day period following
    March 1, 2002.

(17) Consists of 68,726 shares of Common Stock issuable to Mr. Patteson upon
    exercise of outstanding options exercisable within the 60-day period
    following March 1, 2002.

(18) See Notes 5 through 17. Includes 719,139 shares of Common Stock issuable
    upon exercise of outstanding options exercisable within the 60-day period
    following March 1, 2002.

SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

    Our executive officers and directors and persons who own beneficially more
than ten percent of our equity securities are required under Section 16(a) of
the Securities Exchange Act of 1934 to file reports of ownership and changes in
their ownership of our securities with the Securities and Exchange Commission.
They must also furnish copies of these reports to us. Based solely on a review
of the copies of reports furnished to us and written representations that no
other reports were required, we believe that for 2001, our executive officers,
directors and ten percent beneficial owners complied with all applicable
Section 16(a) filing requirements, except that (i) reports, covering in each
case the grant of additional stock options, were filed late on behalf of each of
Messrs. Fordyce, Kempner, Anagnostopoulos, Lewis, and McLachlan; and (ii) one
report, covering the exercise of options to purchase our Common Stock was not
filed on behalf of Robert Charles Ladner, but was later reported on an amended
Annual Statement of Changes in Beneficial Ownership on Form 5.

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

                                   PROPOSAL 1
                             ELECTION OF DIRECTORS

    Our board of directors has fixed the number of directors at nine (9) for the
coming year. Under our charter, our board is divided into three classes, with
each class having as nearly an equal number of directors as possible. The term
of one class expires, with their successors being subsequently elected to a
three-year term, at each annual meeting of stockholders. At the 2002 Annual
Meeting of Stockholders three Class II Directors will be elected to hold office
for three years and until their successors are elected and qualified. Our board
of directors has nominated James W. Fordyce, Thomas L. Kempner and Alix Marduel,
M.D. for election as Class II Directors at the upcoming annual meeting. Each has
consented to serve, if elected. If any nominee is unable to serve, proxies will
be voted for any replacement candidate nominated by our board of directors.

VOTES REQUIRED

    Directors will be elected by a plurality of the votes cast by the
stockholders entitled to vote on this proposal at the meeting. Abstentions,
broker non-votes and votes withheld will not be treated as votes cast for this
purpose and, therefore, will not affect the outcome of the election.

                                       4
<Page>
    The following table contains certain information as of March 31, 2002 about
the nominees for Class II Director and current directors whose term of office
will continue after the annual meeting.

<Table>
<Caption>
                                          BUSINESS EXPERIENCE DURING PAST FIVE YEARS
NAME AND AGE                                       AND OTHER DIRECTORSHIPS               DIRECTOR SINCE
- ------------                           ------------------------------------------------  --------------
                                                                                   
                                                      CLASS II DIRECTORS
                                                 (PRESENT TERM EXPIRES 2002)

James W. Fordyce                       JAMES W. FORDYCE has been a director of Dyax           1995
Age: 59                                since August 1995. Since 1981, he has served as
                                       a general partner of Prince Ventures Limited
                                       Partnership, a venture capital management firm,
                                       and its affiliated partnerships. Prince Venture
                                       Partners IV Limited Partnership is a venture
                                       capital limited partnership, managed by Prince
                                       Ventures Limited Partnership, which specializes
                                       in early stage investments in companies involved
                                       in the medical and life science areas.
                                       Mr. Fordyce is also Managing Member of Fordyce &
                                       Gabrielson LLC, a private investment management
                                       firm. In addition, he is Chairman of the Albert
                                       and Mary Lasker Foundation.

Thomas L. Kempner                      THOMAS L. KEMPNER has been a director of Dyax          1995
Age: 74                                since August 1995, and previously was a director
                                       of Protein Engineering Corporation before its
                                       merger with Dyax. Mr. Kempner is the Chairman
                                       and Chief Executive Officer of Loeb Partners
                                       Corporation, an investment banking, registered
                                       broker/dealer and registered investment advisory
                                       firm. He is also President of Pinpoint Partners
                                       Corporation, the general partner of the Loeb
                                       Investment Partnerships. Mr. Kempner is also a
                                       director of Alcide Corporation, CCC Information
                                       Services Group, Inc., Evercel, Inc., FuelCell
                                       Energy, IGENE BioTechnology, Inc., Insight
                                       Communications Company, Inc., and Intermagnetics
                                       General Corporation.

Alix Marduel                           ALIX MARDUEL, M.D. has been a director of Dyax         1998
Age: 44                                since October 1998. She is a managing director
                                       of Alta Partners, a venture capital firm
                                       investing in information technology and life
                                       science companies. Prior to joining Alta
                                       Partners in 1997, Dr. Marduel was a partner at
                                       Sofinnova, Inc., a venture capital management
                                       firm, which she joined in 1990. Dr. Marduel
                                       holds a medical doctorate from the University of
                                       Paris, is licensed to practice medicine in
                                       Europe and has passed U.S. equivalency exams.
                                       Dr. Marduel has conducted post-doctoral research
                                       in immunology at the University of California at
                                       San Francisco and at Stanford University. Prior
                                       to moving to the United States in 1986, she was
                                       employed by the pharmaceutical company
                                       ICI-Pharma, where she organized clinical trials
                                       in England and France.
</Table>

                                       5
<Page>

<Table>
<Caption>
                                          BUSINESS EXPERIENCE DURING PAST FIVE YEARS
NAME AND AGE                                       AND OTHER DIRECTORSHIPS               DIRECTOR SINCE
- ------------                           ------------------------------------------------  --------------
                                                                                   
                                                     CLASS III DIRECTORS
                                                (PRESENT TERM EXPIRES IN 2003)

Constantine E. Anagnostopoulos         CONSTANTINE E. ANAGNOSTOPOULOS, PH.D. has been a       1991
Age: 79                                director of Dyax since 1991. He is a Managing
                                       General Partner of Gateway Associates L.P., a
                                       venture capital management firm.
                                       Dr. Anagnostopoulos was formerly a corporate
                                       officer of Monsanto Company. He is also a
                                       director of Genzyme Corporation, a biotechnology
                                       company, and Deltagen, Inc., a biopharmaceutical
                                       company.

Henry R. Lewis                         HENRY R. LEWIS, PH.D. has been a director of           1995
Age: 76                                Dyax since August 1995, and previously was a
                                       director of Protein Engineering Corporation
                                       before its merger with Dyax. Dr. Lewis is a
                                       consultant to several companies. From 1986 to
                                       February 1991, Dr. Lewis was the Vice Chairman
                                       of the board of directors of Dennison
                                       Manufacturing Company, a manufacturer and
                                       distributor of products for the stationery,
                                       technical paper and industrial and retail
                                       systems markets. From 1982 to 1986, he was a
                                       Senior Vice President of Dennison Manufacturing
                                       Company. Dr. Lewis was also a director of
                                       Genzyme Corporation, a biotechnology company,
                                       from 1986 until 2000.

David J. McLachlan                     DAVID J. MCLACHLAN has been a director of Dyax         1999
Age: 63                                since May 1999. Mr. McLachlan has been a Senior
                                       Advisor to Genzyme Corporation, a biotechnology
                                       company, since June 1999. He was Genzyme's Chief
                                       Financial Officer and Executive Vice President
                                       from 1989 to 1999. He currently serves as a
                                       director of Hearx, Ltd., a hearing care
                                       company, and Alpha Industries, Inc., a
                                       semiconductor component manufacturer.
</Table>

                                       6
<Page>

<Table>
<Caption>
                                          BUSINESS EXPERIENCE DURING PAST FIVE YEARS
NAME AND AGE                                       AND OTHER DIRECTORSHIPS               DIRECTOR SINCE
- ------------                           ------------------------------------------------  --------------
                                                                                   
                                                      CLASS I DIRECTORS
                                                (PRESENT TERM EXPIRES IN 2004)

Henry E. Blair                         HENRY E. BLAIR has served as the Chairman of the       1989
Age: 58                                Board and President of Dyax since the merger of
                                       Protein Engineering Corporation with Dyax in
                                       August 1995 and as acting Chief Executive
                                       Officer from August 1995 until his appointment
                                       as Chief Executive Officer in April 1997. He
                                       served as a director and officer of Dyax since
                                       its formation in 1989. Mr. Blair is also a
                                       director of, and consultant to Genzyme
                                       Corporation, a biotechnology company, which he
                                       co-founded in 1981. Mr. Blair also co-founded
                                       Biocode, Inc. and GelTex Pharmaceuticals, Inc.
                                       In addition, he is a director of Genzyme
                                       Transgenics Corporation and Esperion
                                       Therapeutics, Inc., and a member of the Board of
                                       Overseers at both Tufts University School of
                                       Medicine and the Lahey Hitchcock Clinic.

Gregory D. Phelps                      GREGORY D. PHELPS has been Vice Chairman and a         1998
Age: 53                                director of Dyax since August 1998. Mr. Phelps
                                       was an executive officer of Genzyme Corporation,
                                       a biotechnology company, from 1991 to 1997, most
                                       recently as Executive Vice President. At
                                       Genzyme, he supervised that company's
                                       therapeutics business, research and development
                                       and corporate development activities.
                                       Mr. Phelps served as Chief Executive Officer of
                                       Viagene, Inc., a biotechnology company, from
                                       1988 to 1990.

John W. Littlechild                    JOHN W. LITTLECHILD has been a director of Dyax        1998
Age: 50                                since 1998. Mr. Littlechild is a general partner
                                       of HealthCare Partners V, L.P., which is the
                                       general partner of HealthCare Ventures V, L.P.
                                       He also serves in a similar capacity with other
                                       related entities. Mr. Littlechild is also a
                                       member of HealthCare Ventures LLC, a venture
                                       management company that, among other things,
                                       provides management services to HealthCare
                                       Ventures V, L.P., and its related entities. From
                                       1984 to 1991, Mr. Littlechild was a Senior Vice
                                       President of Advent International Corporation, a
                                       venture capital company in Boston and London.
                                       Prior to working at Advent in Boston,
                                       Mr. Littlechild was involved in establishing
                                       Advent in the United Kingdom. Mr. Littlechild
                                       serves on the board of directors of various
                                       health care and biotechnology companies,
                                       including Diacrin, Inc., a biotechnology
                                       company, and Orthofix International N.V., a
                                       medical device company.
</Table>

                                       7
<Page>
BOARD AND COMMITTEE MEETINGS

    Our board of directors held seven meetings during 2001. Each of the
directors then in office other than Dr. Marduel and Dr. Anagnostopoulos attended
at least 75% of the aggregate of all meetings of the board of directors and all
meetings of the committees of the board of directors on which such director then
served.

    Our board of directors has standing Audit and Compensation Committees, but
does not have a Nominating Committee. The Audit Committee evaluates our
independent auditors, reviews our audited financial statements, accounting
processes and reporting systems and discusses the adequacy of our internal
financial controls with our management and our auditors. The Audit Committee
also assists the board with the selection of our independent auditors. The
members of the Audit Committee are Henry Lewis (Chair), David McLachlan, and
Thomas Kempner, each of whom is independent as defined by applicable Nasdaq
National Market standards governing the qualifications of Audit Committee
members. The Audit Committee held four meetings during fiscal 2001. The Audit
Committee operates under a written charter adopted by the board which is
included as APPENDIX A to this proxy statement. For more information about the
Audit Committee, See "Audit Committee Report" in this proxy statement.

    Our board also has a standing Compensation Committee that is responsible for
establishing cash compensation policies with respect to our executive officers,
employees, directors and consultants, determining the compensation to be paid to
our executive officers and administering our equity incentive and stock purchase
plans. The members of the Compensation Committee are James Fordyce (Chair),
Constantine Anagnostopoulos, and Henry Lewis. The Compensation Committee held
four meetings during fiscal 2001.

DIRECTOR COMPENSATION

    DIRECTOR FEES.  Beginning in 2001, our directors who are not employees of
Dyax receive compensation for their services as directors in the form of a
retainer of $12,000, payable in quarterly installments, and a fee of $750 for
each meeting attended ($375 for attendance by conference call), plus
reimbursement for travel expenses. We pay non-employee directors who serve as
the chairman of a committee of the board of directors an additional $3,000 per
year. All other non-employee directors who serve on a committee of the board of
directors receive $1,000 per year. Directors who are also our employees receive
no additional compensation for serving as directors.

    STOCK OPTIONS.  In addition, in 2001 all of our non-employee directors
automatically received stock options under our 1995 Equity Plan to purchase
7,500 shares of our Common Stock for each year of their remaining terms of
office. Directors elected at the 2002 Annual Meeting will automatically receive
stock options to purchase 9,000 shares of our Common Stock for each year of
their three-year term, and other non-employee directors will automatically
receive an additional 1,500 shares for each year of their then remaining terms
of office.

CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

    In October 1998, we loaned $1,300,000 to Henry Blair, our Chairman and Chief
Executive Officer, in connection with a purchase of real property. This loan was
secured by Mr. Blair's interest in the real property and by his shares of our
capital stock. Interest accrues on the unpaid principal balance at the rate of
one and a half percent less than the base rate of Fleet National Bank, provided
that the interest rate will not be less than the minimum rate required to avoid
imputed interest for federal tax purposes. This loan is due and payable on
October 30, 2003; provided, however, that it may be accelerated at any time at
the discretion of the board of directors, including upon (i) termination of his
service as our Chairman and Chief Executive Officer, or (ii) if our cash and
marketable investments total less than

                                       8
<Page>
$10,000,000. As of March 1, 2002, $1,286,000 in principal amount remained
outstanding under this loan.

    Mr. Blair serves as an outside director of and consultant to Genzyme
Corporation and as an outside director of Genzyme Transgenics Corporation, a
company in which Genzyme owns approximately 18%. Constantine Anagnostopoulos is
also a director of Genzyme and Mr. McLachlan is a consultant to Genzyme and an
outside director of Genzyme Transgenics Corporation. We subleased a portion of
our research facilities in Cambridge, Massachusetts, from Genzyme at a rate of
$40 per square foot for a total of 16,183 square feet, pursuant to a lease
arrangement, which will expire in April 2002. Prior to the expiration of this
lease, we plan to move our research facility to our new headquarters located at
300 Technology Square. We believe these terms were neither more nor less
favorable than we would have received if we had leased a comparable facility
from a third party.

    We also entered into an agreement with Genzyme in 1998 for the joint
development and commercialization of one of our therapeutic compounds for the
treatment of chronic inflammatory diseases. Under the agreement, we funded the
first $6 million of development costs for the initial disease indication. We
have agreed to establish a limited liability company, in which we and Genzyme
will each own a 50% interest and fund equally all development and
commercialization costs. Genzyme has also extended us a $3 million line of
credit that we may use to fund research and development costs. There is
currently no amount outstanding under this line of credit.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

    Our Compensation Committee determines salaries, incentives and other
compensation for our directors and officers. The Compensation Committee also
administers our equity incentive and stock purchase plans. The Compensation
Committee currently consists of Dr. Anagnostopoulos, Dr. Lewis, and
Mr. Fordyce. For more information regarding the relationship of
Dr. Anagnostopoulos with Genzyme Corporation and its relationships with Dyax,
see the sections of this proxy statement entitled "Share Ownership", "Election
of Directors" and "Certain Relationships and Related Transactions".

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

                                   PROPOSAL 2
        AMENDMENT OF THE AMENDED AND RESTATED 1995 EQUITY INCENTIVE PLAN

GENERAL

    The purpose of our Amended and Restated 1995 Equity Incentive Plan, referred
to as the 1995 Equity Plan, is to attract and retain employees, directors and
consultants and to provide an incentive for these persons to achieve long-range
performance goals. The 1995 Equity Plan permits us to grant equity awards,
sometimes referred to as Awards, to our employees, directors and consultants,
including incentive and non-statutory stock options, stock appreciation rights,
performance shares, restricted stock and stock units. To date, we have granted
only incentive stock options, non-statutory stock options and restricted stock
under the 1995 Equity Plan. On October 26, 2001 and February 7, 2002, our board
of directors voted to amend the 1995 Equity Plan to incorporate an increase in
the number of shares issuable under the 1995 Equity Plan by a total of 2,000,000
shares to an aggregate of 6,500,000 shares, to provide for automatic annual
increases up to an aggregate amount not to exceed 10,250,000 shares and to amend
the limitation on individual grants (as further described below), subject to
adjustment for stock splits and similar capital changes, and to recommend these
amendments to our stockholders for their approval.

    Without giving effect to the proposed amendment, equity awards may be
granted under the 1995 Equity Plan for up to a total of 4,500,000 shares of
Common Stock, subject to adjustment for stock splits and similar capital
changes. Before 2001, we last increased the number of shares of Common

                                       9
<Page>
Stock reserved for issuance under the 1995 Equity Plan in 2000 when we had 147
employees. As of March 1, 2002, 241 employees were eligible to participate in
the 1995 Equity Plan. Since inception of the 1995 Equity Plan, options to
purchase an aggregate of 5,116,555 shares of Common Stock were outstanding or
had been exercised. The weighted average exercise price of all outstanding
options is $9.26 per share. All options granted have a term of ten years.
Pursuant to the 1995 Equity Plan, 239,840 shares of restricted Common Stock have
been issued, none of which have been cancelled. As of March 1, 2002, options to
purchase 1,536,456 shares had been exercised and options to purchase 3,580,099
shares remained outstanding, leaving 383,455 shares available for new equity
awards under the 1995 Equity Plan after taking into account all cancellations of
options. The closing price of our Common Stock as reported by the Nasdaq
National Market on March 1, 2002 was $5.09.

    As the amount of any Awards under the 1995 Equity Plan is within the
Compensation Committee's discretion, total Awards that may be granted for the
current fiscal year are not determinable until completion of the year. Under the
1995 Equity Plan to date, (i) equity awards to purchase a total of 1,314,787
shares of Common Stock have been granted to current executive officers, as a
group (5 persons); (ii) equity awards to purchase a total of 686,441 shares of
Common Stock (which includes 343,000 shares granted to Mr. Phelps in his
capacity as a former executive officer) have been granted to current directors
who are not also executive officers, as a group; and, (iii) equity awards to
purchase a total of 3,353,044 shares of Common Stock were granted to all other
Dyax employees as a group (including current officers who are not directors or
executive officers).

               EQUITY AWARDS GRANTED TO NAMED EXECUTIVE OFFICERS
                  SINCE THE INCEPTION OF THE 1995 EQUITY PLAN

<Table>
<Caption>
                                                    INCENTIVE STOCK   NON-QUALIFIED STOCK    RESTRICTED
NAME                                                 OPTION AWARDS       OPTION AWARDS      STOCK AWARDS
- ----                                                ---------------   -------------------   ------------
                                                                                   
Henry E. Blair....................................      112,955             190,198            114,100
  President and Chief Executive Officer

Gregory D. Phelps.................................      233,000              62,000                 --
  Vice-Chairman of the Board

Stephen S. Galliker...............................      143,628              73,050             47,500
  Executive Vice President, Finance and
  Administration, and Chief Financial Officer

Scott C. Chappel, Ph.D............................      165,815             198,363                 --
  Executive Vice President of Research and
  Technology

David B. Patteson.................................      118,484              65,694                 --
  Executive Vice President, Separations Division,
  President of Biotage, Inc.
</Table>

    No persons, other than Messrs. Blair, Phelps and Galliker, Dr. Chappel and
Robert A. Dishman, Ph.D., a former executive officer, have received five percent
or more of the Awards granted under the 1995 Equity Plan.

    Of the nominees for election as director, Dr. Marduel has received options
to purchase a total of 27,500 shares, Mr. Fordyce has received options to
purchase a total of 41,840 shares and Mr. Kempner has received options to
purchase a total of 32,563 shares.

ADMINISTRATION AND ELIGIBILITY

    Awards are made by the Compensation Committee, which has been designated by
the board of directors to administer the 1995 Equity Plan. Subject to certain
limitations, the Compensation

                                       10
<Page>
Committee may delegate to one or more of our executive officers the power to
make Awards to participants who are not subject to Section 16 of the Securities
Exchange Act of 1934 or "covered employees" for purposes of Section 162(m) of
the Internal Revenue Code of 1986, as amended.

    Options under the 1995 Equity Plan are granted at the discretion of the
Compensation Committee, which determines the recipients and establishes the
terms and conditions of each Award, including the exercise price, the form of
payment of the exercise price, the number of shares subject to the Award and the
time at which such options become exercisable. The exercise price of any
incentive stock option granted under the 1995 Equity Plan may not, however, be
less than the fair market value of the Common Stock on the date of grant and the
term of any such option cannot be greater than 10 years. The exercise price of
any non-statutory stock option is determined by the Compensation Committee.

FEDERAL INCOME TAX CONSEQUENCES RELATING TO STOCK OPTIONS

    INCENTIVE STOCK OPTIONS.  An optionee does not realize taxable income upon
the grant or exercise of an incentive stock option, known as an ISO, under the
1995 Equity Plan. If no disposition of shares issued to an optionee pursuant to
the exercise of an ISO is made by the optionee within two years from the date of
grant or within one year from the date of exercise, then (a) upon sale of such
shares, any amount realized in excess of the option price (the amount paid for
the shares) is taxed to the optionee as a capital gain and any loss sustained
will be a capital loss and (b) no deduction is allowed to Dyax for Federal
income tax purposes. The exercise of ISOs gives rise to an adjustment in
computing alternative minimum taxable income that may result in alternative
minimum tax liability for the optionee.

    If shares of Common Stock acquired upon the exercise of an ISO are disposed
of prior to the expiration of the two-year and one-year holding periods
described above, referred to as a disqualifying disposition, then (a) the
optionee realizes ordinary income in the year of disposition in an amount equal
to the excess (if any) of the fair market value of the shares at exercise (or,
if less, the amount realized on a sale of such shares) over the option price
thereof and (b) Dyax is entitled to deduct this amount. Any further gain
realized is taxed as a capital gain and does not result in any deduction to us.
A disqualifying disposition in the year of exercise will generally avoid the
alternative minimum tax consequences of the exercise of an ISO.

    NON-STATUTORY STOCK OPTIONS.  No income is realized by the optionee at the
time a non-statutory option is granted. Upon exercise, (a) ordinary income is
realized by the optionee in an amount equal to the difference between the option
price and the fair market value of the shares on the date of exercise and
(b) we receive a tax deduction for the same amount. Upon disposition of the
shares, appreciation or depreciation after the date of exercise is treated as a
capital gain or loss and will not result in any deduction by Dyax.

PROPOSED AMENDMENT TO THE 1995 EQUITY PLAN

    The board of directors voted on October 26, 2001 to amend the 1995 Equity
Plan to increase the number of shares of Common Stock reserved for Awards under
the 1995 Equity Plan by 1,000,000 to an aggregate of 5,500,000 shares in order
to provide sufficient shares to permit Dyax to make its annual option Awards to
substantially all of its employees. In December 2001, Dyax obtained confirmation
from the Nasdaq National Market that the 1995 Equity Plan was "broadly-based"
within the meaning of Marketplace Rule 4350(i)(1)(A), and, as such, stockholder
approval was not required in order to amend the 1995 Equity Plan to implement
this increase in the number of shares of Common Stock reserved under the 1995
Equity Plan and to render the annual Awards. However, the board of directors
wishes to obtain stockholder approval of the October 2001 amendment in order to
ensure that all shares of Common Stock reserved for issuance pursuant to Awards
under the 1995 Equity Plan may be treated as incentive stock options under the
Internal Revenue Code.

                                       11
<Page>
    Recognizing that Dyax needs additional shares for Awards to new hires and
for annual employee Awards in the coming year, our board of directors in 2002
also voted to recommend to stockholders that an additional l,000,000 shares, and
shares subject to automatic annual increases, be reserved under the 1995 Equity
Plan to increase the number of shares of Common Stock available for Awards, and
to amend the limitation on individual grants. Accordingly, our board of
directors recommends that the stockholders approve an amendment to:

    - change the number of shares reserved since inception under the plan to an
      aggregate of 6,500,000 shares, subject to adjustment for stock splits,
      stock dividends and similar capital changes;

    - provide that as of January 1 of each year, commencing with the year 2003,
      the number of shares of Common Stock available for Awards that may be made
      under the 1995 Equity Plan shall automatically increase by a number equal
      to the lesser of (i) One Million Two Hundred Fifty Thousand (1,250,000)
      shares, (ii) 5% of the fully diluted outstanding shares of Common Stock of
      Dyax on such date or (iii) such lesser amount as may be determined by
      resolution of the board at any date before or within ninety (90) days
      after January 1 of the respective year;

    - provide that the 1,250,000 limitation on annual increases and any number
      of shares determined under the preceding provision for annual increases
      shall also be subject to adjustment for stock splits, stock dividends and
      similar capital changes;

    - provide that the maximum aggregate number of shares received since
      inception under the plan (consisting of the 6,500,000 shares and
      subsequent annual increases) shall not exceed Ten Million Two Hundred
      Fifty Thousand (10,250,000) shares; and

    - amend the limitation on individual grants to provide that the maximum
      number of shares of Common Stock subject to Awards that may be granted to
      any participant shall not exceed 225,000 shares in the aggregate in any
      calendar year, except that for grants to a new employee during the
      calendar year in which his or her service as an employee first commences
      such number shall not exceed 450,000 shares, and that both limits are
      subject to adjustment for stock splits, stock dividends and similar
      capital changes.

    Stockholder approval of the 2,000,000 share increase and the provision for
automatic increases is required for Dyax to grant Awards with respect to the
second 1,000,000 shares proposed for stockholder approval and with respect to
the shares available for grant pursuant to the subsequent yearly increases. It
is also required to ensure that these shares may be treated as incentive stock
options under the Internal Revenue Code. This proposed amendment, as well as the
October 2001 amendment, is intended to ensure that a sufficient number of shares
of Common Stock are available to be issued to eligible persons until 2005.

    Stockholder approval of the amendment to the current limit on the maximum
number of shares of Common Stock subject to Awards that may be granted to any
participant under the 1995 Equity Plan is required for us to comply with the
performance-based compensation exception set forth in Section 162(m) of the
Internal Revenue Code. Section 162(m) of the Internal Revenue Code generally
disallows a tax deduction to publicly traded companies for compensation in
excess of $1,000,000 accrued with respect to a company's chief executive officer
or any of the four most highly compensated officers, unless certain conditions
are met that include stockholder approval of this provision. Stockholder
approval of the amendment to this provision is sought to ensure that Dyax is
permitted the maximum tax deduction for compensation paid under the 1995 Equity
Plan.

VOTES REQUIRED

    The affirmative vote of a majority of the shares represented in person or by
proxy at the annual meeting and entitled to vote on this proposal will
constitute the approval of the proposed amendment

                                       12
<Page>
to the 1995 Equity Plan. Abstentions will count as votes against the amendment
and broker non-votes will not be counted.

          THE BOARD OF DIRECTORS RECOMMENDS A VOTE FOR THIS PROPOSAL.

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

                                   PROPOSAL 3
               AMENDMENT OF THE 1998 EMPLOYEE STOCK PURCHASE PLAN

GENERAL

    The 1998 Employee Stock Purchase Plan, referred to as the Purchase Plan,
provides Dyax's full-time employees the opportunity to purchase shares of Common
Stock through automatic payroll deductions on favorable terms. Like Dyax's 1995
Equity Plan, the Purchase Plan helps Dyax attract and retain top quality
personnel, motivates employees to acquire an equity stake in Dyax and provides
an incentive for them to achieve long-range performance goals. On February 7,
2002, Dyax's board of directors voted to amend the Purchase Plan, subject to
stockholder approval, to incorporate the increase in the aggregate number of
shares of Common Stock subject to purchase under the Purchase Plan by 102,200
shares to 200,000 shares, subject to adjustment for stock splits and similar
capital changes.

    Without giving effect to the increase authorized by the board of directors
on February 7, 2002, an aggregate of 97,800 shares of Common Stock have been
reserved for issuance under the Purchase Plan, subject to adjustment for stock
splits and similar capital changes. As of March 1, 2002, 185 U.S. employees were
eligible to participate in the Purchase Plan and 22,653 shares had been
purchased under the Purchase Plan. The closing price of Dyax's Common Stock on
March 1, 2002, as reported on the Nasdaq National Market, was $5.09.

ADMINISTRATION AND ELIGIBILITY

    The Purchase Plan is intended to qualify as an "employee stock purchase
plan" under Section 423 of the Internal Revenue Code. By action of Dyax's
Compensation Committee on February 15, 2001, Mr. Blair, in his capacity as the
Chairman, President and Chief Executive Officer of Dyax, was delegated the
authority to grant rights to purchase shares of Common Stock under the Purchase
Plan. Mr. Blair determines the frequency and duration of individual offerings
under the Purchase Plan and the date(s) when stock may be purchased. All of
Dyax's full-time U.S. employees, as defined in the Purchase Plan, are eligible
to participate.

    Eligible employees participate voluntarily and may withdraw from any
offering at any time before stock is purchased. Participation terminates
automatically upon termination of employment for any reason. The purchase price
per share in an offering is 85% of the lower of the fair market value of a share
of Common Stock on the offering date or on the applicable purchase date. Each
offering has a single purchase date on the last business day of the sixth month
of the offering. The purchase price may be paid only through payroll deductions
at the rate of between one percent and ten percent of the participant's
compensation in effect at that time, as chosen by the participant prior to the
beginning of the offering. As determined by Dyax's Compensation Committee, an
employee's payroll deductions may not exceed $21,250 in any single calendar
year. Amounts withheld by Dyax, but not used for the purchase of stock, are
repaid to the employee following the termination of the offering.

    In accordance with Section 423 of the Internal Revenue Code, no employee may
participate in an offering under the Purchase Plan if, immediately after the
right to acquire shares of Common Stock in the offering is granted, the employee
would own 5% or more of the total voting power or value of all classes of stock
of Dyax (including stock that may be purchased through subscriptions under the

                                       13
<Page>
Purchase Plan or any other options). Additionally, subject to the lower limits
established by Dyax, an employee may not buy more than $25,000 worth of stock
(determined by the fair market value of the Common Stock at the time the right
to purchase is granted) through the Purchase Plan, or any other employee stock
purchase plans qualified under Section 423, in any calendar year. No employee's
purchases in any calendar year may exceed fifteen percent of his or her annual
rate of compensation.

    The Purchase Plan may be amended or terminated at any time by the board of
directors, or by any committee or executive to whom authority over the Purchase
Plan has been granted; provided, however, that any proposed amendment to the
Purchase Plan increasing the number of shares offered thereunder requires
stockholder approval.

    The initial offering under the Purchase Plan commenced January 29, 2001 and
terminated June 30, 2001. Subsequent offerings are to begin on July 1 and
January 1 of each year during the term of the Purchase Plan. Since the Purchase
Plan's inception (i) no rights to purchase shares of Common Stock have been
granted to current executive officers as a group (5 persons); and (ii) rights to
purchase a total of 22,653 shares of Common Stock were granted to all other Dyax
employees as a group (including current officers who are not executive
officers). Directors who are not also executive officers, a group which includes
the nominees for election as director, are not eligible to participate in the
Purchase Plan.

FEDERAL INCOME TAX CONSEQUENCES RELATING TO THE PURCHASE PLAN

    If the stockholders approve the amendment of the Purchase Plan, participants
realize no taxable income at the commencement of an offering or at the time
shares are purchased under the Purchase Plan. If a participant holds shares
purchased under the Purchase Plan for at least two years from the offering
commencement date, then upon sale of the shares, the participant will be treated
as having received taxable compensation income of fifteen percent of the fair
market value of the stock at the commencement of the offering (or, if less, any
amount realized on sale of such shares in excess of the purchase price). No
deduction will be allowed to Dyax for Federal income tax purposes upon the
purchase of shares or, if the participant waits the prescribed period to sell,
upon sale. However, if the participant does not wait the prescribed period to
sell, he or she will be treated as having received taxable compensation income
upon sale equal to the excess of the fair market value of the stock on the date
of purchase over the actual purchase price, and Dyax will be allowed to deduct
that amount. In either case, any difference over or under the participant's tax
cost (the purchase price plus the amount of taxable compensation income that the
participant recognizes upon sale of the shares) will be treated as a capital
gain or loss.

    Assuming stockholder approval, if a participant dies during the two-year
holding period while owning shares purchased under the Purchase Plan, fifteen
percent of the fair market value of the stock at the commencement of the
offering period (or, if less, the fair market value of such shares on the date
of death in excess of the purchase price) is taxed to the participant as
ordinary income in the year of death, and Dyax would not be allowed a deduction
for Federal income tax purposes.

    If Dyax issues shares under the Purchase Plan without stockholder approval,
a participant would be treated as having received taxable compensation income at
the time of purchase equal to the excess of the fair market value of the stock
on the date of purchase over the actual purchase price, and Dyax would be
allowed to deduct that amount.

PROPOSED AMENDMENT TO PURCHASE PLAN

    The board of directors voted on February 7, 2002 to increase the number of
shares of Common Stock subject to purchase under the Purchase Plan by 102,200
shares to a total of 200,000 shares, subject to adjustment for stock splits and
similar capital changes. This proposed amendment is intended to ensure that a
sufficient number of shares of Common Stock are available to be issued to plan
participants in the future.

                                       14
<Page>
VOTES REQUIRED

    The affirmative vote of a majority of the shares represented in person or by
proxy at the annual meeting and entitled to vote on this proposal will
constitute the approval of the proposed amendment to the Purchase Plan.
Abstentions will count as votes against the amendment and broker non-votes will
not be counted.

          THE BOARD OF DIRECTORS RECOMMENDS A VOTE FOR THIS PROPOSAL.

                      EXECUTIVE OFFICERS AND KEY EMPLOYEES

    The following contains certain information as of March 31, 2002 about the
current executive officers and key employees of Dyax:

<Table>
<Caption>
NAME                                     AGE                              POSITION
- ----                                   --------   --------------------------------------------------------
                                            
Henry E. Blair*......................     58      Chairman of the Board, President and Chief Executive
                                                  Officer

Stephen S. Galliker*.................     55      Executive Vice President, Finance and Administration,
                                                  and Chief Financial Officer

Scott C. Chappel, Ph.D.*.............     51      Executive Vice President of Research and Technology

David B. Patteson*...................     46      President of Biotage, Inc.

Jack H. Morgan*......................     50      Senior Vice President, Corporate Development and
                                                  Business Operations

Robert Charles Ladner, Ph.D..........     58      Senior Vice President and Chief Science Officer
</Table>

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

*   Executive officer

    HENRY E. BLAIR has served as the Chairman of the Board and President of Dyax
since the merger of Protein Engineering Corporation with Dyax in August 1995 and
as acting Chief Executive Officer from August 1995 until his appointment as
Chief Executive Officer in April 1997. He also served as a director and officer
of Dyax since its formation in 1989. Mr. Blair is also a director of and
consultant to Genzyme Corporation, a biotechnology company, which he co-founded
in 1981. Mr. Blair also co-founded Biocode, Inc. and GelTex
Pharmaceuticals, Inc. In addition, he is a director of Genzyme Transgenics
Corporation and Esperion Therapeutics, Inc., and a member of the Board of
Overseers at both Tufts University School of Medicine and the Lahey Hitchcock
Clinic.

    STEPHEN S. GALLIKER has served Dyax as Executive Vice President, Finance and
Administration, and Chief Financial Officer since September 1999. He was Chief
Financial Officer of Excel Switching Corporation, a developer and manufacturer
of open switching platforms for telecommunications networks, from July 1996 to
September 1999 and was Excel's Vice President, Finance and Administration from
September 1997. Mr. Galliker was employed by Ultracision, Inc., a developer and
manufacturer of ultrasonically powered surgical instruments from September 1992
to June 1996. At Ultracision, Inc., Mr. Galliker was Chief Financial Officer and
Vice President of Finance until November 1995 and Chief Operating Officer from
December 1995 to June 1996.

    SCOTT C. CHAPPEL, PH.D. has served as Executive Vice President of Research
and Technology since March 2001, prior to which he was Senior Vice President,
Research since he joined Dyax in June 1999. Prior to Dyax, Dr. Chappel was Chief
Scientist at Serono Inc., a biotechnology company, from 1995 to 1999. From 1991
to 1994, he served as Chief Scientific Officer at Diacrin, Inc., a biotechnology
company. Dr. Chappel was Vice President of Research for Serono from 1989 to
1991.

                                       15
<Page>
    DAVID B. PATTESON has been Executive Vice President of the Separations
Division since March 2001 and President of Biotage, Inc. since its formation in
October 2000. He joined Dyax in November 1998 as Senior Vice President and
President of Biotage Products, Separations Division. From 1994 until he joined
Dyax, Mr. Patteson was an executive at Siebe plc, a diversified engineering and
electronics company, most recently as Vice President and General Manager, Siebe
Measurement and Controls Division. Prior to joining Siebe, Mr. Patteson was
President of Perstorp Analytical, Inc., a laboratory and process analytical
instruments company.

    JACK H. MORGAN has been Senior Vice President, Corporate Development and
Business Operations since joining Dyax in May 2001. Mr. Morgan also served as a
consultant to Syntonix Pharmaceuticals, Inc., a pharmaceutical company, from
January to May 2001, and as a consultant to PerkinElmer, Inc., a technology
company, and Caremark Inc., a pharmaceutical services company, bewteen July 1999
and April 2000. From May to December 2000, Mr. Morgan served as the transitional
President and Chief Executive Officer of Admetric Biochem Inc., an early stage
drug discovery technology company. On October 30, 2001, Admetric BioChem Inc.
filed a voluntary petition pursuant to Chapter 7 of the U.S. Bankruptcy Code and
its bankruptcy proceeding is still pending. From 1991 to 1999, Mr. Morgan was an
executive with Genetics Institute, a biotechnology company, where he headed
Corporate Development from October 1993 to February 1998 and was Vice
President & General Manager, responsible for commercial operations in North
America, from March 1998 to June 1999. Mr. Morgan held various positions at
Baxter Healthcare Corporation from 1978 to 1990, including Vice President--
Corporate Planning, Vice President--Global Marketing, Planning, and Finance,
Renal Therapy Division, Vice President--Finance and Planning, Home Therapy
Group, and Vice President--Marketing U.S. Dialysis Division.

    ROBERT CHARLES LADNER, PH.D. became Senior Vice President and Chief Science
Officer of Dyax in August 1995. He was a co-founder of Protein Engineering
Corporation where he served as Senior Vice President and Scientific Director
from 1987 until its merger with Dyax in August 1995. Previously, Dr. Ladner
served as Senior Scientist of Genex Corp., where he was an inventor of single
chain antibodies.

                             EXECUTIVE COMPENSATION
            COMPENSATION COMMITTEE REPORT ON EXECUTIVE COMPENSATION

    The Compensation Committee of the board of directors determines the
compensation to be paid to Dyax's executive officers, including the Chief
Executive Officer. The Committee also administers Dyax's 1995 Equity Plan,
including the grant of stock options and other awards under that plan, as well
as Dyax's Purchase Plan. The Committee is currently composed of Mr. Fordyce
(Chairman), and Drs. Anagnostopoulos and Lewis. This report is submitted by the
Committee and addresses the compensation policies for fiscal year 2001 as they
affected Mr. Blair, as Chairman, President and Chief Executive Officer, and
Dyax's other executive officers, including the four most highly compensated
executive officers other than Mr. Blair who are named in the Summary
Compensation Table.

COMPENSATION PHILOSOPHY

    Dyax's executive compensation policy is designed to attract, retain and
reward executive officers who contribute to Dyax's long-term success and to
maintain a competitive salary structure as compared with other biotechnology
companies. The compensation program seeks to align compensation with the
achievement of business objectives and individual and corporate performance.
Bonuses are included to encourage effective individual performance relative to
Dyax's current plans and objectives. Stock option grants are key components of
the executive compensation program and are intended to provide executives with
an equity interest in Dyax in order to link a meaningful portion of the
executive's compensation with the performance of Dyax's Common Stock.

                                       16
<Page>
    In executing its compensation policy, Dyax seeks to reward each executive's
achievement of designated objectives relating to Dyax's annual and long term
performance and individual fulfillment of responsibilities. While compensation
survey data are useful guides for comparative purposes, Dyax believes that a
successful compensation program also requires the application of judgment and
subjective determinations of individual performance, and to that extent the
Compensation Committee applies its judgment in reconciling the program's
objectives with the realities of retaining valued employees.

EXECUTIVE COMPENSATION PROGRAM

    Dyax's executive compensation package for the Chief Executive Officer and
the other named executive officers is composed of three elements:

    - base salary;

    - annual incentive bonuses based on individual performance; and

    - initial, annual and other periodic grants of stock options under the 1995
      Equity Plan.

    NAMED EXECUTIVE OFFICERS.  Each of the named executive officers, other than
our Chief Executive Officer and Mr. Patteson, has entered into an employment
agreement with Dyax. The minimum annual base salary provided for in each
agreement was fixed based upon the executive's salary history and internal and
external equity considerations. Near the beginning of each fiscal year, the
Compensation Committee then reviews the base salaries paid to the named
executive officers. The annual base salary for 2001 for each named executive
officer was adjusted in light of the executive's prior performance, tenure and
responsibility, as well as independent compensation data.

    For fiscal 2001, the Committee established a maximum bonus opportunity for
each of the senior officers, expressed as a percentage of base salary, ranging
from 30% to 40%. Bonuses were tied to the Committee's judgment regarding
individual performance and the contribution of the executive to Dyax's
performance. In February 2002, the Compensation Committee reviewed with
Mr. Blair the performance of each named executive officer and determined the
bonuses to be paid to them based on their achievement of their performance goals
for 2001. The Committee also directed that a portion of each executive officer's
bonus for 2002 be based on corporate performance.

    Executive officer compensation also includes long-term incentives afforded
by options to purchase Common Stock. The purposes of the stock option grant
program are to reinforce the mutuality of long-term interests between Dyax's
employees and stockholders, and to assist in the attraction and retention of
important key executives, managers and individual contributors who are essential
to Dyax's growth and development.

    In December 2001, the Committee approved annual option grants of 40,000
shares to Dr. Chappel, 30,000 shares to Mr. Phelps, 40,000 shares to
Mr. Galliker and 35,000 to Mr. Patteson, as shown in the Summary Compensation
Table.

    CHIEF EXECUTIVE OFFICER.  The Compensation Committee established a
compensation package for Mr. Blair based on an analysis of compensation data for
comparable executive positions gathered from surveys prepared by independent
compensation consultants.

    The Committee established a 2001 base salary of $420,000 for Mr. Blair and a
target bonus opportunity of 33% of his base salary. The increase in Mr. Blair's
2001 base salary from his 2000 base compensation resulted from the Committee's
determination that an increase was merited based on performance as well as to
maintain Mr. Blair's salary at the midpoint of a range of chief executive
officer salaries in comparable companies reviewed by the Committee.

                                       17
<Page>
    Mr. Blair's target bonus percentage was fixed at 33% of his base salary.
Mr. Blair's target bonus opportunity was based on the Committee's qualitative
evaluation of his performance. In January 2002, the Committee awarded Mr. Blair
a bonus of $124,740, representing 90% of his target bonus opportunity for 2001.
In addition, in December 2001, the Committee granted Mr. Blair options to
purchase 100,000 shares of Common Stock.

COMPENSATION DEDUCTIBILITY

    Section 162(m) of the Internal Revenue Code denies a tax deduction to a
public corporation for annual compensation in excess of one million dollars paid
to its Chief Executive Officer and its four other highest compensated officers.
This provision excludes certain types of "performance based compensation" from
the compensation subject to the limit. Although Dyax currently does not expect
to have compensation exceeding this one million dollar limit, the 1995 Equity
Plan contains an individual annual limit on the number of stock options and
stock appreciation rights that may be granted under the plan so that the awards
will qualify for the exclusion from the limitation on deductibility for
performance-based compensation. The Committee will continue to assess the impact
of Section 162(m) on its compensation practices and determine what further
action, if any, is appropriate.

                                          By the Compensation Committee,
                                          JAMES W. FORDYCE, CHAIR
                                          CONSTANTINE E. ANAGNOSTOPOULOS
                                          HENRY R. LEWIS

                                       18
<Page>
STOCK PERFORMANCE GRAPH

    The following graph shows a comparison of the cumulative total stockholder
returns on our Common Stock over the period from August 15, 2000 (the first
trading day of our Common Stock) to December 31, 2001 as compared with that of
the Nasdaq US Index and Nasdaq Pharmaceuticals Index, based on an initial
investment of $100 in each on August 15, 2000. Total stockholder return is
measured by dividing share price change plus dividends, if any, for each period
by the share price at the beginning of the respective period, assuming
reinvestment of any dividends.

              COMPARISON OF CUMULATIVE TOTAL RETURN OF DYAX CORP.,
                 NASDAQ STOCK MARKET (U.S. COMPANIES) INDEX AND
                          NASDAQ PHARMACEUTICALS INDEX

                                    [GRAPH]

<Table>
<Caption>
                                             8/15/00    9/29/00    12/29/00   3/30/01    6/29/01    9/28/01    12/31/01
                                             --------   --------   --------   --------   --------   --------   --------
                                                                                          
Dyax Corp..................................    100       169.90     82.34      31.07      73.79      37.36      42.60
Nasdaq Stock Market (U.S. Companies)
  Index....................................    100        95.15     63.71      47.56      56.05      38.89      50.56
Nasdaq Pharmaceuticals Index...............    100       111.48     92.90      68.80      85.47      68.90      79.18
</Table>

                                       19
<Page>
SUMMARY COMPENSATION TABLE

    The following table sets forth certain compensation information for our
Chief Executive Officer and each of the other four most highly compensated
executive officers whose salary and bonus for the year ended December 31, 2001
exceeded $100,000. We refer to these persons as the named executive officers.

                           SUMMARY COMPENSATION TABLE

<Table>
<Caption>
                                                                  LONG-TERM COMPENSATION
                                                                          AWARDS
                                      ANNUAL COMPENSATION         ----------------------
                                -------------------------------   SHARES OF COMMON STOCK       ALL OTHER
NAME AND PRINCIPAL POSITION       YEAR     SALARY($)   BONUS($)   UNDERLYING OPTIONS(#)    COMPENSATION($)(1)
- ---------------------------     --------   ---------   --------   ----------------------   ------------------
                                                                            
Henry E. Blair................    2001      418,269    124,740           100,000                  6,003(2)
  President and Chief             2000      375,047    150,000            90,000                  1,161
  Executive Officer               1999      324,869    100,000            30,000                    131

Gregory D. Phelps.............    2001      320,192     96,300            30,000                   5573(3)
  Vice-Chairman of the Board      2000      277,451     90,000            92,000                    621
                                  1999      228,916     50,000            15,000                     84

Stephen S. Galliker...........    2001      230,193     62,370            40,000                 21,026(4)(5)
  Executive Vice President,       2000      209,232     75,000            39,178                 15,621(5)
  Finance and Administration,     1999       51,210     16,667           137,500                     21
  and Chief Financial Officer

Scott C. Chappel, Ph.D........    2001      249,231     60,000           155,000                 31,036(6)
  Executive Vice President of     2000      230,621     50,000            39,178                 29,246(7)
  Research and Technology         1999      197,558     49,500           160,000                     84

David B. Patteson.............    2001      219,231     66,000            35,000                  3,901(8)
  Executive Vice President,       2000      199,484     52,000            39,178                  5,664(9)
  Separations Division,           1999      172,405     63,658            10,000                     --
  President of Biotage, Inc.
</Table>

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

(1) Unless otherwise noted, this amount represents premiums paid by Dyax for
    group term life insurance.

(2) Includes $5,100 in 401(k) matching paid by Dyax.

(3) Includes $5,090 in 401(k) matching paid by Dyax.

(4) Includes $5,088 in 401(k) matching paid by Dyax.

(5) Includes $15,000 paid to Mr. Galliker as a housing allowance.

(6) Includes $5,100 in 401(k) matching paid by Dyax and $25,453 in principal and
    accrued interest on a loan to Dr. Chappel that was forgiven by Dyax in 2001.

(7) Includes $28,625 in principal and accrued interest on a loan to Dr. Chappel
    that was forgiven by Dyax in 2000.

(8) Includes $3,586 in 401(k) matching paid by Dyax.

(9) Includes $5,259 in relocation expenses reimbursed to Mr. Patteson in 2000.

                                       20
<Page>
OPTION GRANTS AND POTENTIAL REALIZABLE VALUES TABLE

    The following table sets forth certain information concerning option grants
made to the named executive officers through December 31, 2001.

                       OPTION GRANTS IN LAST FISCAL YEAR

<Table>
<Caption>
                                                                                                     POTENTIAL REALIZABLE
                                                                                                       VALUE AT ASSUMED
                                            INDIVIDUAL GRANTS                                           ANNUAL RATES OF
                       -----------------------------------------------------------                        STOCK PRICE
                           NUMBER OF                                                                   APPRECIATION FOR
                           SECURITIES       PERCENT OF TOTAL OPTIONS   EXERCISE OR                      OPTION TERM(2)
                       UNDERLYING OPTIONS   GRANTED TO EMPLOYEES IN    BASE PRICE     EXPIRATION     ---------------------
NAME (A)                 GRANTED (#)(1)           FISCAL YEAR            ($/SH)          DATE          5%($)      10%($)
- --------               ------------------   ------------------------   -----------   -------------   ---------   ---------
                                                                                               
Henry E. Blair.......      100,000(3)                 6.36                10.40        12/14/11        746,897   1,805,335
Gregory D. Phelps....         30,000                  1.91                10.40        12/14/11        224,069     541,601
Stephen S.
Galliker.............       40,000(4)                 2.54                10.40        12/14/11        298,759     722,134
Scott C. Chappel,
Ph.D.................        125,000                  7.95                 8.00         3/22/11      1,233,622   2,556,669
                            40,000(5)                 1.91                10.40        12/14/11        224,069     541,601
David B. Patteson....       35,000(6)                 2.23                10.40        12/14/11        261,414     631,867
</Table>

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

(1) All options reported are nonstatutory stock options, except as noted. These
    options vest as to 1/48th of the total shares per month beginning on the
    date of grant.

(2) The values in this column are given for illustrative purposes; they do not
    reflect our estimate or projection of future stock prices. The values are
    based on an assumption that our Common Stock's market price will appreciate
    at the stated rate, compounded annually, from the date of the option grant
    until the end of the option's 10-year term. Actual gains, if any, on stock
    option exercises will depend upon the future performance of our Common
    Stock's price, which will benefit all stockholders proportionately.

(3) Includes 5,803 shares subject to an incentive stock option.

(4) Includes 5,093 shares subject to an incentive stock option.

(5) Includes 3,244 shares subject to an incentive stock option.

(6) Includes 4,766 shares subject to an incentive stock option.

OPTION EXERCISES AND YEAR-END VALUES TABLE

    The following table sets forth certain information concerning exercisable
and unexercisable stock options held by the named executive officers as of
December 31, 2001.

              AGGREGATED OPTION EXERCISES IN LAST FISCAL YEAR AND
                          FISCAL YEAR-END OPTION VALUE

<Table>
<Caption>
                                                                     NUMBER OF SECURITIES
                                                                          UNDERLYING
                                                                      UNEXERCISED OPTIONS    VALUE OF UNEXERCISED IN-THE-
                                           SHARES                    AT FISCAL YEAR-END(#)     MONEY OPTIONS AT FISCAL
                                         ACQUIRED ON      VALUE          EXERCISABLE/                YEAR-END($)
NAME                                     EXERCISE(#)   REALIZED($)       UNEXERCISABLE       EXERCISABLE/UNEXERCISABLE(1)
- ----                                     -----------   -----------   ---------------------   ----------------------------
                                                                                 
Henry E. Blair.........................        --             --       105,842 / 186,458         769,809 / 227,053
Gregory D. Phelps......................        --             --       110,312 / 115,875         827,739 / 422,119
Stephen S. Galliker....................    10,000         80,000       99,258 / 106,778          802,483 / 651,452
Scott C. Chappel, Ph.D.................    10,000         91,100       43,733 / 203,028          163,769 / 696,224
David B. Patteson......................     3,500         35,000       56,504 / 124,174          418,980 / 556,275
</Table>

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

(1) Based on the difference between the exercise price of the option and the
    $10.97 closing price of the underlying Common Stock on December 31, 2001.

                                       21
<Page>
EXECUTIVE EMPLOYMENT AGREEMENTS

    Our only named executive officers with employment agreements are
Mr. Phelps, Mr. Galliker and Dr. Chappel. We also have an employment agreement
with Dr. Ladner.

    Mr. Phelps is entitled to an annual base salary of $200,000 under his
employment agreement. In addition, we granted Mr. Phelps options to purchase a
total of 148,000 shares of Common Stock at an exercise price of $2.00 per share.
In consideration of this grant, Mr. Phelps agreed to cancel an option to
purchase 48,000 shares that he had previously received while he was a
consultant. These options vest as to 1/48th of the total shares per month
beginning on the date of grant. Mr. Phelps's employment agreement provides that
if we terminate him for any reason, 50% of his unvested options will become
immediately exercisable. The agreement also provides that 50% of Mr. Phelps'
unvested options will become immediately exercisable following a change in
control of Dyax if he is terminated or quits because the terms of his employment
have been adversely changed.

    Mr. Galliker is entitled to receive a minimum base salary of $185,000 under
his employment agreement. We will also pay Mr. Galliker a housing allowance of
$15,000 a year. Mr. Galliker received three option grants, giving him options to
purchase a total of 137,500 shares of our common stock at an exercise price of
$2.00 per share. These options become exercisable as to 3,750 shares per month
during the first two years of Mr. Galliker's employment and as to approximately
1,771 shares per month during the third and fourth years of his employment.
Pursuant to the terms of his agreement, Mr. Galliker purchased 22,500 shares of
restricted Common Stock, all of which are currently vested. Mr. Galliker also
purchased 25,000 shares of Common Stock at $2.00 per share which are not subject
to a repurchase option. We have a right of first refusal if Mr. Galliker
transfers these shares. If we terminate Mr. Galliker without cause, we must
continue to pay him at his current salary for six months, reduced by any
compensation that Mr. Galliker earns for other work performed during this
six-month period. The agreement also provides that 50% of Mr. Galliker's options
will become immediately exercisable following a change in control of the company
if he is terminated or quits because the terms of his employment have been
adversely changed.

    Dr. Chappel is entitled to an annual base salary of $200,000 under his
employment agreement. In addition, we granted Dr. Chappel options to purchase a
total of 150,000 shares of Common Stock at an exercise price of $2.00 per share
upon his commencing employment with us. These options vest as to 1/48th of the
total shares per month beginning on the date of grant. Half of these options may
also vest in blocks based on Dr. Chappel achieving certain performance based
criteria. If we terminate Dr. Chappel without cause, we must pay him his base
salary for a period of six months as severance. After this period, these
payments will continue on a monthly basis for the earlier of six months or
Dr. Chappel's attainment of comparable employment.

                             AUDIT COMMITTEE REPORT

    In the course of its oversight of our financial reporting process, the Audit
Committee of the board of directors has:

    - reviewed and discussed with management and PricewaterhouseCoopers LLP,
      Dyax's independent auditor, Dyax's audited financial statements for the
      fiscal year ended December 31, 2001;

    - discussed with the auditor the matters required to be discussed by
      Statement on Auditing Standards No. 61, COMMUNICATION WITH AUDIT
      COMMITTEES;

    - received the written disclosures and the letter from the auditor required
      by Independence Standards Board Standard No. 1, INDEPENDENCE DISCUSSIONS
      WITH AUDIT COMMITTEES;

    - reviewed with management and the auditor Dyax's critical accounting
      policies;

    - discussed with the auditor the quality and adequacy of Dyax's internal
      controls;

                                       22
<Page>
    - discussed with the auditor any relationships that may impact their
      objectivity and independence; and

    - considered whether the provision of non-audit services by the auditor is
      compatible with maintaining the auditor's independence.

    Based on the foregoing review and discussions, the Committee recommended to
the board of directors that the audited financial statements be included in
Dyax's Annual Report on Form 10-K for the year ended December 31, 2001 for
filing with the Securities and Exchange Commission.

    The Committee has also reviewed and recommended revision of the Audit
Committee Charter, the current form of which is attached to this proxy statement
as APPENDIX A.

                                          By the Audit Committee,
                                          HENRY R. LEWIS, CHAIR
                                          DAVID J. MCLACHLAN
                                          THOMAS L. KEMPNER

INFORMATION CONCERNING OUR AUDITORS

    The firm of PricewaterhouseCoopers LLP, independent accountants, examined
our financial statements for the year ended December 31, 2001. The board of
directors has appointed PricewaterhouseCoopers LLP to serve as our independent
auditors for its fiscal year ending December 31, 2002. Representatives of
PricewaterhouseCoopers LLP are expected to attend the annual meeting to respond
to appropriate questions, and will have the opportunity to make a statement if
they desire.

    The fees for services provided to us by PricewaterhouseCoopers LLP in 2001
were as follows:

<Table>
                                                      
Audit Fees.............................................  $321,000.00
All Other Fees.........................................  $ 24,000.00
</Table>

OTHER MATTERS

    The board of directors does not know of any business to come before the
meeting other than the matters described in the notice. If other business is
properly presented for consideration at the meeting, the enclosed proxy
authorizes the persons named therein to vote the shares in their discretion.

DEADLINE FOR STOCKHOLDER PROPOSALS

    In order for a stockholder proposal to be considered for inclusion in Dyax's
proxy materials for the 2003 Annual Meeting of Stockholders, it must be received
by Dyax at 300 Technology Square, Cambridge, Massachusetts 02139 (or such other
address as is listed as Dyax's primary executive offices in its periodic reports
under the Securities Exchange Act of 1934) no later than December 19, 2002.

    In addition, Dyax's bylaws require a stockholder who wishes to bring
business before or propose director nominations at an annual meeting to give
advance written notice to Dyax's Secretary between March 17, 2003 and April 1,
2003 (assuming the 2003 annual meeting of stockholders is held on May 16, 2003).

EXPENSES OF SOLICITATION

    We will bear the cost of the solicitation of proxies, including the charges
and expenses of brokerage firms and others of forwarding solicitation material
to beneficial owners of Common Stock. We have retained Georgeson Shareholder to
assist with the solicitation of proxies for a fee of approximately $12,500, plus
reimbursement of out-of-pocket expenses. In addition to the use of mails,
proxies may be solicited by officers and any of our regular employees in person
or by telephone, facsimile and e-mail.

                                       23
<Page>
                                                                      APPENDIX A

                                   DYAX CORP.
                            AUDIT COMMITTEE CHARTER
   (AS AMENDED AND RESTATED AT A MEETING OF DIRECTORS HELD ON MARCH 26, 2002)

PURPOSE

    The principal purpose of the Audit Committee is to assist the Board of
Directors in fulfilling its responsibility to oversee management's conduct of
the Company's financial reporting process, including by reviewing the financial
reports and other financial information provided by the Company, the Company's
systems of internal accounting and financial controls, and the annual
independent audit process.

    In discharging its oversight role, the Committee is granted the power to
investigate any matter brought to its attention with full access to all books,
records, facilities and personnel of the Company and the power to retain outside
counsel, auditors or other experts for this purpose.

    The outside auditor is ultimately accountable to the Board and the
Committee, as representatives of the stockholders. The Board and the Committee
shall have the ultimate authority and responsibility to select, evaluate and,
where appropriate, replace the outside auditor. The Committee shall be
responsible for overseeing the independence of the outside auditor.

    This Charter shall be reviewed for adequacy on an annual basis by the Board.

MEMBERSHIP

    The Committee shall be comprised of not less than three members of the
Board, and the Committee's composition will meet the requirements of the Nasdaq
Audit Committee Requirements. Accordingly, all of the members will be directors:

    - Who have no relationship to the Company that may interfere with the
      exercise of their independence from management and the Company; and

    - Who are financially literate or who become financially literate within a
      reasonable period of time after appointment to the Committee.

    In addition, at least one member of the Committee will have accounting or
related financial management expertise.

KEY RESPONSIBILITIES

    The Committee's role is one of oversight, and it is recognized that the
Company's management is responsible for preparing the Company's financial
statements and that the outside auditor is responsible for auditing those
financial statements.

    The following functions shall be the common recurring activities of the
Committee in carrying out its oversight role. The functions are set forth as a
guide and may be varied from time to time as appropriate under the
circumstances.

    - The Committee shall review with management and the outside auditor the
      audited financial statements to be included in the Company's Annual Report
      on Form 10-K and the Annual Report to Stockholders, and shall review and
      consider with the outside auditor the matters required to be discussed by
      Statement on Auditing Standards No. 61.

                                      A-1
<Page>
    - As a whole, or through the Committee chair, the Committee shall review
      with the outside auditor, prior to filing with the Securities and Exchange
      Commission, the Company's interim financial information to be included in
      the Company's Quarterly Reports on Form 10-Q and the matters required to
      be discussed by SAS No. 61.

    - The Committee shall periodically discuss with management and the outside
      auditor the quality and adequacy of the Company's internal controls and
      discuss with the outside auditor how the Company's financial systems and
      controls compare with industry practices.

    - The Committee shall periodically review with management and the outside
      auditor the quality, as well as the acceptability, of the Company's
      accounting policies and discuss with the outside auditor how the Company's
      accounting policies compare with industry practices.

    - The Committee shall review with management and the outside auditor the
      Company's accounting policies which may be viewed as critical.

    - The Committee shall request from the outside auditor annually a formal
      written statement delineating all relationships between the auditor and
      the Company consistent with Independence Standards Board Standard No. 1,
      discuss with the outside auditor any such disclosed relationships and
      their impact on the outside auditor's independence, and take or recommend
      that the Board take appropriate action regarding the independence of the
      outside auditor.

    - The Committee shall be consulted regarding retention of the outside
      auditor to perform any significant services for the Company, other than
      audit, tax and SEC reporting services, and the effect of such retention on
      the outside auditor's independence.

    - The Committee, subject to any action that may be taken by the Board, shall
      have the ultimate authority and responsibility to select (or nominate for
      stockholder approval), evaluate and, where appropriate, replace the
      outside auditor.

    - The Committee shall review with management and the outside auditor any
      material financial or other arrangements of the Company which do not
      appear on the Company's financial statements and any transactions or
      courses of dealing with third parties that are significant in size or
      involve terms or other aspects that differ from those that would likely be
      negotiated with independent parties and which arrangements or transactions
      are relevant to an understanding of the Company's financial statements.

    - The Committee shall review any issue of significant financial misconduct,
      which shall be brought to the attention of the Committee for its
      consideration by the outside auditor, management or any other party.

    - The Committee shall report to the Board whether, based on the foregoing
      reviews and discussions, the Committee recommends that the financial
      statements be included in the Company's Annual Report on Form 10-K.

                                      A-2




                                                                      APPENDIX B

                                   DYAX CORP.

                 AMENDED AND RESTATED 1995 EQUITY INCENTIVE PLAN



Section 1.  PURPOSE

         The purpose of the Dyax Corp. 1995 Equity Incentive Plan (the "Plan")
is to attract and retain key employees and directors and consultants of the
Company and its Affiliates, to provide an incentive for them to assist the
Company to achieve long-range performance goals, and to enable them to
participate in the long-term growth of the Company.

Section 2.  DEFINITIONS

         "Affiliate" means any business entity in which the Company owns
directly or indirectly 50% or more of the total combined voting power or has a
significant financial interest as determined by the Committee.

         "Award" means any Option, Stock Appreciation Right, Performance Share,
Restricted Stock, Stock Unit or Other Stock-Based Award awarded under the Plan.

         "Board" means the Board of Directors of the Company.

         "Code" means the Internal Revenue Code of 1986, as amended from time to
time, and any successor to such Code.

         "Committee" means the Compensation Committee of the Board or such other
committee of the Board appointed by the Board to administer the Plan or a
specified portion thereof; provided, however, that in any instance the Board of
Directors may take away any action delegated to the Committee hereunder. If a
Committee is authorized to grant Awards to a Reporting Person or a "covered
employee" within the meaning of Section 162(m) of the Code, each member shall be
a "Non-Employee Director" or the equivalent within the meaning of Rule 16b-3
under the Exchange Act or an "outside director" or the equivalent within the
meaning of Section 162(m) of the Code, respectively.

         "Common Stock" or "Stock" means the Common Stock, $0.01 par value, of
the Company.

         "Company" means Dyax Corp. (formerly named Biotage, Inc.).

         "Designated Beneficiary" means the beneficiary designated by a
Participant, in a manner determined by the Committee, to receive amounts due or
exercise rights of the Participant in the event of the Participant's death. In
the absence of an effective designation by a Participant, "Designated
Beneficiary" shall mean the Participant's estate.


                                      B-1





         "Effective Date" means July 13, 1995.

         "Fair Market Value" means, with respect to Common Stock or any other
property, the fair market value of such property as determined by the Committee
in good faith or in the manner established by the Committee from time to time.

         "Incentive Stock Option" means an option to purchase shares of Common
Stock awarded to a Participant under Section 6 that is intended to meet the
requirements of Section 422 of the Code or any successor provision.

         "Nonstatutory Stock Option" means an option to purchase shares of
Common Stock awarded to a Participant under Section 6 that is not intended to be
an Incentive Stock Option.

         "Option" means an Incentive Stock Option or a Nonstatutory Stock
Option.

         "Other Stock-Based Award" means an Award, other than an Option, Stock
Appreciation Right, Performance Share, Restricted Stock or Stock Unit, having a
Common Stock element and awarded to a Participant under Section 11.

         "Participant" means a person selected by the Committee to receive an
Award under the Plan.

         "Performance Cycle" or "Cycle" means the period of time selected by the
Committee during which performance is measured for the purpose of determining
the extent to which an award of Performance Shares has been earned.

         "Performance Shares" mean shares of Common Stock, which may be earned
by the achievement of performance goals, awarded to a Participant under Section
8.

         "Reporting Person" means a person subject to Section 16 of the
Securities Exchange Act of 1934 or any successor provision.

         "Restricted Period" means the period of time selected by the Committee
during which an Award may be forfeited to the Company pursuant to the terms and
conditions of such Award.

         "Restricted Stock" means shares of Common Stock subject to forfeiture
awarded to a Participant under Section 9.

         "Stock Appreciation Right" or "SAR" means a right to receive any excess
in value of shares of Common Stock over the exercise price awarded to a
Participant under Section 7.

         "Stock Unit" means an award of Common Stock or units that are valued in
whole or in part by reference to, or otherwise based on, the value of Common
Stock, awarded to a Participant under Section 10.


                                      B-2





Section 3.  ADMINISTRATION

         The Plan shall be administered by the Committee; provided, however,
that in any instance the Board of Directors may take any action delegated
hereunder to the Committee. The Committee shall have authority to adopt, alter
and repeal such administrative rules, guidelines and practices governing the
operation of the Plan as it shall from time to time consider advisable, and to
interpret the provisions of the Plan. The Committee's decisions shall be final
and binding. To the extent permitted by applicable law, the Committee may
delegate to one or more executive officers of the Company the power to make
Awards to Participants who are not Reporting Persons or covered employees and
all determinations under the Plan with respect thereto, provided that the
Committee shall fix the maximum amount of such Awards for all such Participants
and a maximum for any one Participant.

Section 4.  ELIGIBILITY

         All employees and, in the case of Awards other than Incentive Stock
Options, directors and consultants of the Company or any Affiliate, capable of
contributing significantly to the successful performance of the Company, other
than a person who has irrevocably elected not to be eligible, are eligible to be
Participants in the Plan. Incentive Stock Options may be awarded only to persons
eligible to receive such Options under the Code.

Section 5.  STOCK AVAILABLE FOR AWARDS

         (a) Subject to adjustment under subsection (c), and after giving effect
to the 0.652-for-one reverse stock split of the Company's Common Stock affected
in March 1998, Awards may be made under the Plan for up to Six Million Five
Hundred Thousand (6,500,000) shares of Common Stock, which number includes
shares previously issued upon exercise of options granted under the Plan, plus
the additional shares described in subsection (b), but in no event more than Ten
Million Two Hundred Fifty Thousand (10,250,000) shares. The maximum number of
shares of Common Stock subject to Awards that may be granted to any Participant
shall not exceed 225,000 shares in the aggregate in any calendar year, except
that for grants to a new employee during the calendar year in which his or her
service as an employee first commences such number shall not exceed 450,000
shares, and that both limits are subject to adjustment under subsection (c). If
any Award in respect of shares of Common Stock expires or is terminated
unexercised or is forfeited, the shares subject to such Award, to the extent of
such expiration, termination or forfeiture, shall again be available for award
under the Plan. Common Stock issued through the assumption or substitution of
outstanding grants from an acquired company shall not reduce the shares
available for Awards under the Plan. Shares issued under the Plan may consist in
whole or in part of authorized but unissued shares or treasury shares.

         (b) As of January 1 of each year, commencing with the year 2003, the
number of shares of Common Stock available for Awards that may be made under the
Plan shall automatically increase by a number equal to the lesser of (i) One
Million Two Hundred Fifty Thousand (1,250,000) shares, (ii) 5% of the fully
diluted outstanding shares of Common Stock of the Company on such date or (iii)
such lesser amount as may be determined by resolution of the Board at any date
before or within ninety (90) days after January 1 of the respective year. The
number of shares set forth in clause (ii) of the preceding sentence, as well as
any number of


                                      B-3





shares determined in accordance with the preceding sentence, shall be subject to
adjustment under subsection (c).

         (c) In the event that the Committee determines that any stock dividend,
extraordinary cash dividend, creation of a class of equity securities,
recapitalization, reorganization, merger, consolidation, split-up, spin-off,
combination, exchange of shares, warrants or rights offering to purchase Common
Stock at a price substantially below fair market value, or other similar
transaction affects the Common Stock such that an adjustment is required in
order to preserve the benefits or potential benefits intended to be made
available under the Plan, then the Committee (subject, in the case of Incentive
Stock Options, to any limitation required under the Code) shall equitably adjust
any or all of (i) the number and kind of shares in respect of which Awards may
be made under the Plan, (ii) the number and kind of shares subject to
outstanding Awards, and (iii) the award, exercise or conversion price with
respect to any of the foregoing, and if considered appropriate, the Committee
may make provision for a cash payment with respect to an outstanding Award,
provided that the number of shares subject to any Award shall always be a whole
number.

Section 6.  STOCK OPTIONS

         (a) Subject to the provisions of the Plan, the Committee may award
Incentive Stock Options and Nonstatutory Stock Options and determine the number
of shares to be covered by each Option, the option price therefor and the
conditions and limitations applicable to the exercise of the Option. The terms
and conditions of Incentive Stock Options shall be subject to and comply with
Section 422 of the Code or any successor provision and any regulations
thereunder. See subsection (b) below. No Incentive Stock Option may be granted
hereunder more than ten years after the Effective Date.

         (b) The Committee shall establish the option price at the time each
Option is awarded, which price shall not be less than 100% of the Fair Market
Value of the Common Stock on the date of award with respect to Incentive Stock
Options. Nonstatutory Stock Options may be granted at such prices as the
Committee may determine.

         (c) Each Option shall be exercisable at such times and subject to such
terms and conditions as the Committee may specify in the applicable Award or
thereafter. The Committee may impose such conditions with respect to the
exercise of Options, including conditions relating to applicable federal or
state securities laws, as it considers necessary or advisable.

         (d) No shares shall be delivered pursuant to any exercise of an Option
until payment in full of the option price therefor is received by the Company.
Such payment may be made in whole or in part in cash or, to the extent permitted
by the Committee at or after the award of the Option, by delivery of a note or
shares of Common Stock owned by the optionee, including Restricted Stock, or by
retaining shares otherwise issuable pursuant to the Option, in each case valued
at their Fair Market Value on the date of delivery or retention, or such other
lawful consideration as the Committee may determine.


                                      B-4





         (e) The Committee may provide that, subject to such conditions as it
considers appropriate, upon the delivery or retention of shares to the Company
in payment of an Option, the Participant automatically be awarded an Option for
up to the number of shares so delivered.

Section 7.  STOCK APPRECIATION RIGHTS

         (a) Subject to the provisions of the Plan, the Committee may award SARs
in tandem with an Option (at or after the award of the Option), or alone and
unrelated to an Option. SARs in tandem with an Option shall terminate to the
extent that the related Option is exercised, and the related Option shall
terminate to the extent that the tandem SARs are exercised. SARs granted in
tandem with Options shall have an exercise price not less than the exercise
price of the related Option. SARs granted alone and unrelated to an Option may
be granted at such exercise prices as the Committee may determine.

         (b) An SAR related to an Option, which SAR can only be exercised upon
or during limited periods following a change in control of the Company, may
entitle the Participant to receive an amount based upon the highest price paid
or offered for Common Stock in any transaction relating to the change in control
or paid during the thirty-day period immediately preceding the occurrence of the
change in control in any transaction reported in any stock market in which the
Common Stock is usually traded.

Section 8.  PERFORMANCE SHARES

         (a) Subject to the provisions of the Plan, the Committee may award
Performance Shares and determine the number of such shares for each Performance
Cycle and the duration of each Performance Cycle. There may be more than one
Performance Cycle in existence at any one time, and the duration of Performance
Cycles may differ from each other. The payment value of Performance Shares shall
be equal to the Fair Market Value of the Common Stock on the date the
Performance Shares are earned or, in the discretion of the Committee, on the
date the Committee determines that the Performance Shares have been earned.

         (b) The Committee shall establish performance goals for each Cycle, for
the purpose of determining the extent to which Performance Shares awarded for
such Cycle are earned, on the basis of such criteria and to accomplish such
objectives as the Committee may from time to time select. During any Cycle, the
Committee may adjust the performance goals for such Cycle as it deems equitable
in recognition of unusual or non-recurring events affecting the Company, changes
in applicable tax laws or accounting principles, or such other factors as the
Committee may determine.

         (c) As soon as practicable after the end of a Performance Cycle, the
Committee shall determine the number of Performance Shares that have been earned
on the basis of performance in relation to the established performance goals.
The payment values of earned Performance Shares shall be distributed to the
Participant or, if the Participant has died, to the Participant's Designated
Beneficiary, as soon as practicable thereafter. The Committee shall determine,
at or after the time of award, whether payment values will be settled in whole
or in part in cash or other property, including Common Stock or Awards.


                                      B-5





Section 9.  RESTRICTED STOCK

         (a) Subject to the provisions of the Plan, the Committee may award
shares of Restricted Stock and determine the duration of the Restricted Period
during which, and the conditions under which, the shares may be forfeited to the
Company and the other terms and conditions of such Awards. Shares of Restricted
Stock may be issued for no cash consideration or such minimum consideration as
may be required by applicable law.

         (b) Shares of Restricted Stock may not be sold, assigned, transferred,
pledged or otherwise encumbered, except as permitted by the Committee, during
the Restricted Period. Shares of Restricted Stock shall be evidenced in such
manner as the Committee may determine. Any certificates issued in respect of
shares of Restricted Stock shall be registered in the name of the Participant
and unless otherwise determined by the Committee, deposited by the Participant,
together with a stock power endorsed in blank, with the Company. At the
expiration of the Restricted Period, the Company shall deliver such certificates
to the Participant or if the Participant has died, to the Participant's
Designated Beneficiary.

Section 10.  STOCK UNITS

         (a) Subject to the provisions of the Plan, the Committee may award
Stock Units subject to such terms, restrictions, conditions, performance
criteria, vesting requirements and payment rules as the Committee shall
determine.

         (b) Shares of Common Stock awarded in connection with a Stock Unit
Award shall be issued for no cash consideration or such minimum consideration as
may be required by applicable law.

Section 11.  OTHER STOCK-BASED AWARDS

         (a) Subject to the provisions of the Plan, the Committee may make other
awards of Common Stock and other awards that are valued in whole or in part by
reference to, or are otherwise based on, Common Stock, including without
limitation convertible preferred stock, convertible debentures, exchangeable
securities and Common Stock awards or options. Other Stock-Based Awards may be
granted either alone or in tandem with other Awards granted under the Plan
and/or cash awards made outside of the Plan.

         (b) The Committee may establish performance goals, which may be based
on performance goals related to book value, subsidiary performance or such other
criteria as the Committee may determine, Restricted Periods, Performance Cycles,
conversion prices, maturities and security, if any, for any Other Stock-Based
Award. Other Stock-Based Awards may be sold to Participants at the face value
thereof or any discount therefrom or awarded for no consideration or such
minimum consideration as may be required by applicable law.

Section 12.  GENERAL PROVISIONS APPLICABLE TO AWARDS

         (a) DOCUMENTATION. Each Award under the Plan shall be evidenced by a
writing delivered to the Participant specifying the terms and conditions thereof
and containing such other terms and conditions not inconsistent with the
provisions of the Plan as the Committee considers


                                      B-6





necessary or advisable to achieve the purposes of the Plan or to comply with
applicable tax and regulatory laws and accounting principles.

         (b) COMMITTEE DISCRETION. Each type of Award may be made alone, in
addition to or in relation to any other type of Award. The terms of each type of
Award need not be identical, and the Committee need not treat Participants
uniformly. Except as otherwise provided by the Plan or a particular Award, any
determination with respect to an Award may be made by the Committee at the time
of award or at any time thereafter.

         (c) SETTLEMENT. The Committee shall determine whether Awards are
settled in whole or in part in cash, Common Stock, other securities of the
Company, Awards or other property. The Committee may permit a Participant to
defer all or any portion of a payment under the Plan, including the crediting of
interest on deferred amounts denominated in cash and dividend equivalents on
amounts denominated in Common Stock.

         (d) DIVIDENDS AND CASH AWARDS. In the discretion of the Committee, any
Award under the Plan may provide the Participant with (i) dividends or dividend
equivalents payable currently or deferred with or without interest, and (ii)
cash payments in lieu of or in addition to an Award.

         (e) TERMINATION OF EMPLOYMENT. The Committee shall determine the effect
on an Award of the disability, death, retirement or other termination of
employment of a Participant and the extent to which, and the period during
which, the Participant's legal representative, guardian or Designated
Beneficiary may receive payment of an Award or exercise rights thereunder.

         (f) CHANGE IN CONTROL. In order to preserve a Participant's rights
under an Award in the event of a change in control of the Company (as defined by
the Committee), the Committee in its discretion may, at the time an Award is
made or at any time thereafter, take one or more of the following actions: (i)
provide for the acceleration of any time period relating to the exercise or
realization of the Award, (ii) provide for the purchase of the Award upon the
Participant's request for an amount of cash or other property that could have
been received upon the exercise or realization of the Award had the Award been
currently exercisable or payable, (iii) adjust the terms of the Award in a
manner determined by the Committee to reflect the change in control, (iv) cause
the Award to be assumed, or new rights substituted therefor, by another entity,
or (v) make such other provision as the Committee may consider equitable and in
the best interests of the Company.

         (g) LOANS. The Committee may authorize the making of loans or cash
payments to Participants in connection with any Award under the Plan, which
loans may be secured by any security, including Common Stock, underlying or
related to such Award (provided that such Loan shall not exceed the Fair Market
Value of the security subject to such Award), and which may be forgiven upon
such terms and conditions as the Committee may establish at the time of such
loan or at any time thereafter.

         (h) WITHHOLDING TAXES. The Participant 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


                                      B-7





of Awards under the Plan 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 shares retained from the
Award creating the tax obligation, valued at their 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
the Participant.

         (i) FOREIGN NATIONALS. Awards may be made to Participants who are
foreign nationals or employed outside the United States on such terms and
conditions different from those specified in the Plan as the Committee considers
necessary or advisable to achieve the purposes of the Plan or to comply with
applicable laws.

         (j) AMENDMENT OF AWARD. The Committee may amend, modify or terminate
any outstanding Award, including substituting therefor another Award of the same
or a different type, changing the date of exercise or realization and converting
an Incentive Stock Option to a Nonstatutory Stock Option, provided that the
Participant's consent to such action shall be required unless the Committee
determines that the action, taking into account any related action, would not
materially and adversely affect the Participant.

Section 13.  MISCELLANEOUS

         (a) NO RIGHT TO EMPLOYMENT. No person shall have any claim or right to
be granted an Award, and the grant of an Award shall not be construed as giving
a Participant the right to continued employment. The Company expressly reserves
the right at any time to dismiss a Participant free from any liability or claim
under the Plan, except as expressly provided in the applicable Award.

         (b) NO RIGHTS AS STOCKHOLDER. Subject to the provisions of the
applicable Award, no Participant or Designated Beneficiary shall have any rights
as a stockholder with respect to any shares of Common Stock to be distributed
under the Plan until he or she becomes the holder thereof. A Participant to whom
Common Stock is awarded shall be considered the holder of the Stock at the time
of the Award except as otherwise provided in the applicable Award.

         (c) EFFECTIVE DATE. Subject to the approval of the stockholders of the
Company, the Plan shall be effective on the Effective Date. Before such
approval, Awards may be made under the Plan expressly subject to such approval.

         (d) AMENDMENT OF PLAN. The Committee may amend, suspend or terminate
the Plan or any portion thereof at any time, subject to any stockholder approval
that the Committee determines to be necessary or advisable.

         (e) GOVERNING LAW. The provisions of the Plan shall be governed by and
interpreted in accordance with the laws of the State of Delaware.

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

THIS PLAN WAS APPROVED BY THE BOARD OF DIRECTORS ON JULY 13, 1995.


                                      B-8





THIS PLAN WAS APPROVED BY THE STOCKHOLDERS ON AUGUST 8, 1995.

THIS PLAN WAS AMENDED BY THE BOARD OF DIRECTORS ON OCTOBER 17, 1996, AND SUCH
AMENDMENT WAS APPROVED BY THE STOCKHOLDERS EFFECTIVE AS OF OCTOBER 23, 1996.

THIS PLAN WAS FURTHER AMENDED BY THE BOARD OF DIRECTORS ON OCTOBER 22, 1997 AND
ON JANUARY 28, 1998, AND SUCH AMENDMENTS WERE APPROVED BY THE STOCKHOLDERS
EFFECTIVE AS OF MARCH 23, 1998.

THIS PLAN WAS FURTHER AMENDED BY THE BOARD OF DIRECTORS ON AUGUST 13, 1998, AND
SUCH AMENDMENT WAS APPROVED BY THE STOCKHOLDERS EFFECTIVE AS OF AUGUST 28, 1998.

THIS PLAN WAS FURTHER AMENDED BY THE BOARD OF DIRECTORS ON AUGUST 5, 1999, AND
SUCH AMENDMENT WAS APPROVED BY THE STOCKHOLDERS EFFECTIVE AS OF OCTOBER 29,
1999.

THIS PLAN WAS FURTHER AMENDED BY THE BOARD OF DIRECTORS ON MARCH 16, 2000, AND
SUCH AMENDMENT WAS APPROVED BY THE STOCKHOLDERS EFFECTIVE AS OF MARCH 20, 2000.

THIS PLAN WAS FURTHER AMENDED BY THE BOARD OF DIRECTORS ON OCTOBER 26, 2001.

THIS PLAN WAS FURTHER AMENDED BY THE BOARD OF DIRECTORS ON FEBRUARY 7, 2002, AND
SUCH AMENDMENT WAS APPROVED BY THE STOCKHOLDERS EFFECTIVE AS OF _______________.







                                      B-9





                                                                      APPENDIX C

                                   DYAX CORP.

                        1998 EMPLOYEE STOCK PURCHASE PLAN
                       (AS AMENDED THROUGH FEBRUARY 2002)

         1.       PURPOSE.

         The purpose of this 1998 Employee Stock Purchase Plan (the "Plan") is
to provide employees of Dyax Corp. (the "Company"), who wish to become
shareholders of the Company, an opportunity to purchase Common Stock of the
Company (the "Shares"). The Plan is intended to qualify as an "employee stock
purchase plan" within the meaning of Section 423 of the Internal Revenue Code of
1986, as amended (the "Code").

         2.       ELIGIBLE EMPLOYEES.

         Subject to the provisions of Sections 7, 8 and 9 below, any individual
who is a full-time employee (as defined below) of the Company, or any of its
subsidiaries (as defined in Section 424(f) of the Code) the employees of which
are designated by the Board of Directors as eligible to participate in the Plan,
is eligible to participate in any Offering of Shares (as defined in Section 3
below) made by the Company hereunder. Full-time employees shall include all
employees whose customary employment is:

                  (a)  20 hours or more per week and

                  (b)  more than five months

in the calendar year during which said Offering Date occurs or in the calendar
year immediately preceding such year.

         3.       OFFERING DATES.

         From time to time, the Company, by action of the Board of Directors,
will grant rights to purchase Shares to employees eligible to participate in the
Plan pursuant to one or more offerings (each of which is an "Offering" on a date
or series of dates (each of which is an "Offering Date") designated for this
purpose by the Board of Directors.

         4.       PRICES.

         The price per share for each grant of rights hereunder shall be the
lesser of:

                  (a) eighty-five percent (85%) of the fair market value of a
                  Share on the Offering Date on which such right was granted;
                  or

                  (b) eighty-five percent (85%) of the fair market value of a
                  Share on the date such right is exercised.


                                      C-1





         At its discretion, the Board of Directors may determine a higher price
for a grant of rights.

         5.       EXERCISE OF RIGHTS AND METHOD OF PAYMENT.

                  (a) Rights granted under the Plan will be exercisable
periodically on specified dates as determined by the Board of Directors.

                  (b) The method of payment for Shares purchased upon exercise
of rights granted hereunder shall be through regular payroll deductions or by
lump sum cash payment or both, as determined by the Board of Directors. No
interest shall be paid upon payroll deductions unless specifically provided for
by the Board of Directors.

                  (c) Any payments received by the Company from a participating
employee and not utilized for the purchase of Shares upon exercise of a right
granted hereunder shall be promptly returned to such employee by the Company
after termination of the right to which the payment relates.

         6.       TERM OF RIGHTS.

         The total period from an Offering Date to the last date on which rights
granted on that Offering Date are exercisable (the "Offering Period") shall in
no event be longer than twenty-seven (27) months. The Board of Directors when it
authorizes an Offering may designate one or more exercise periods during the
Offering Period. Rights granted on an Offering Date shall be exercisable in full
on the Offering Date or in such proportion on the last day of each exercise
period as the Board of Directors determines.

         7.       SHARES SUBJECT TO THE PLAN.

         No more than 200,000 Shares may be sold pursuant to rights granted
under the Plan. Appropriate adjustments in the above figure, in the number of
Shares covered by outstanding rights granted hereunder, in the exercise price of
the rights and in the maximum number of Shares which an employee may purchase
(pursuant to Section 9 below) shall be made to give effect to any mergers,
consolidations, reorganizations, recapitalizations, stock splits, stock
dividends or other relevant changes in the capitalization of the Company
occurring after the effective date of the Plan, provided that no fractional
Shares shall be subject to a right and each right shall be adjusted downward to
the nearest full Share. Any agreement of merger or consolidation will include
provisions for protection of the then existing rights of participating employees
under the Plan. Either authorized and unissued Shares or issued Shares
heretofore or hereafter reacquired by the Company may be made subject to rights
under the Plan. If for any reason any right under the Plan terminates in whole
or in part, Shares subject to such terminated right may again be subjected to a
right under the Plan.

         8.       LIMITATIONS ON GRANTS.

                  (a) No employee shall be granted a right hereunder if such
employee, immediately after the right is granted, would own stock or rights to
purchase stock possessing


                                      C-2





five percent (5%) or more of the total combined voting power or value of all
classes of stock of the Company, or of any subsidiary, computed in accordance
with Section 423(b)(3) of the Code.

                  (b) No employee shall be granted a right which permits his
right to purchase shares under all employee stock purchase plans of the Company
and its subsidiaries to accrue at a rate which exceeds twenty-five thousand
dollars ($25,000) (or such other maximum as may be prescribed from time to time
by the Code) of the fair market value of such Shares (determined at the time
such right is granted) for each calendar year in which such right is outstanding
at any time in accordance with the provisions of Section 423(b)(8) of the Code.

                  (c) No right granted to any participating employee under an
Offering, when aggregated with rights granted under any other Offering still
exercisable by the participating employee, shall cover more shares than may be
purchased at an exercise price equal to fifteen percent (15%) of the employee's
annual rate of compensation on the date the employee elects to participate in
the Offering or such lesser percentage as the Board of Directors may determine.

         9.       LIMIT ON PARTICIPATION.

         Participation in an Offering shall be limited to eligible employees who
elect to participate in such Offering in the manner, and within the time
limitations, established by the Board of Directors when it authorizes the
Offering.

         10.      CANCELLATION OF ELECTION TO PARTICIPATE.

         An employee who has elected to participate in an Offering may cancel
such election as to all (but not part) of the unexercised rights granted under
such Offering by giving written notice of such cancellation to the Company
before the expiration of any exercise period. Any amounts paid by the employee
for the Shares or withheld for the purchase of Shares from the employee's
compensation through payroll deductions shall be paid to the employee, without
interest, unless otherwise determined by the Board of Directors, upon such
cancellation.

         11.      TERMINATION OF EMPLOYMENT.

         Upon the termination of employment for any reason, including the death
of the employee, before the date on which any rights granted under the Plan are
exercisable, all such rights shall immediately terminate and amounts paid by the
employee for the Shares or withheld for the purchase of Shares from the
employee's compensation through payroll deductions shall be paid to the employee
or to the employee's estate, without interest unless otherwise determined by the
Board of Directors.

         12.      EMPLOYEES' RIGHTS AS SHAREHOLDERS.

         No participating employee shall have any rights as a shareholder in the
Shares covered by a right granted hereunder until such right has been exercised,
full payment has been made for the corresponding Shares and the Share
certificate is actually issued.


                                      C-3





         13.      RIGHTS NOT TRANSFERABLE.

         Rights under the Plan are not assignable or transferable by a
participating employee and are exercisable only by the employee.

         14.      AMENDMENTS TO OR DISCONTINUATION OF THE PLAN.

         The Board of Directors of the Company shall have the right to amend,
modify or terminate the Plan at any time without notice; provided, however, that
the then existing rights of all participating employees shall not be adversely
affected thereby, and provided further that, subject to the provisions of
Section 7 above, no such amendment to the Plan shall, without the approval of
the shareholders of the Company, increase the total number of Shares which may
be offered under the Plan.

         15.      EFFECTIVE DATE AND APPROVALS.

         This Plan became effective on January 31, 1998, the date it was adopted
by the Board of Directors, provided that it is approved by the shareholders of
the Company within twelve (12) months before or after the date of adoption.

         The Company's obligation to offer, sell and deliver its Shares under
the Plan is subject to (i) the approval of any governmental authority required
in connection with the authorized issuance or sale of such Shares, (ii)
satisfaction of the listing requirements of any national securities exchange on
which the Shares are then listed and (iii) compliance, in the opinion of the
Company's counsel with, all applicable federal and state securities and other
laws.

         16.      TERM OF PLAN.

         No rights shall be granted under the Plan after January 30, 2008.

         17.      ADMINISTRATION OF THE PLAN.

         The Board of Directors or any committee or person(s) to whom it
delegates its authority (the "Administrator") shall administer, interpret and
apply all provisions of the Plan as it deems necessary to meet special
circumstances not anticipated or covered expressly by the Plan. Nothing
contained in this Section shall be deemed to authorize the Administrator to
alter or administer the provisions of the Plan in a manner inconsistent with the
provisions of Section 423 of the Code.








                                      C-4



                              (FRONT OF PROXY CARD)

                                   DYAX CORP.

                         ANNUAL MEETING OF STOCKHOLDERS

           THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS

The undersigned stockholder of Dyax Corp. hereby appoints Henry E. Blair,
Stephen S. Galliker and Nathaniel S. Gardiner, or any of them, with full power
of substitution in each, as proxies to cast all votes which the undersigned
stockholder is entitled to cast at the annual meeting of stockholders (the
"Annual Meeting") to be held at 2:00 p.m., local time, on Thursday, May 16,
2002, at the offices of Dyax Corp., 300 Technology Square, Cambridge,
Massachusetts 02139, and at any adjournments of the meeting, upon the following
matters. The undersigned stockholder hereby revokes any proxy or proxies
heretofore given.

This proxy will be voted as directed by the undersigned stockholder. Unless
contrary direction is given, this proxy will be voted FOR the election of the
nominees listed in Proposal 1, FOR the amendment as described in Proposal 2 and
FOR the amendment as described in Proposal 3, and in accordance with the
determination of a majority of the board of directors as to any other matters.
The undersigned stockholder may revoke this proxy at any time before it is voted
by delivering either a written notice of revocation of the proxy or a duly
executed proxy bearing a later date to the Secretary, or by attending the Annual
Meeting and voting in person. The undersigned stockholder hereby acknowledges
receipt of the Notice of Annual Meeting and Proxy Statement.

If you receive more than one proxy card, please sign and return all cards in the
accompanying envelope.

             (CONTINUED AND TO BE DATED AND SIGNED ON REVERSE SIDE.)

                             (REVERSE OF PROXY CARD)

       PLEASE DATE, SIGN AND MAIL YOUR PROXY CARD BACK AS SOON AS POSSIBLE

                         ANNUAL MEETING OF STOCKHOLDERS

                                   DYAX CORP.

                                  MAY 16, 2002

[X] PLEASE MARK YOUR VOTES AS IN THIS EXAMPLE.


1.    To elect three directors to serve for three year terms (Class II)

                              WITHHOLD                NOMINEES
          FOR                AUTHORITY            James W. Fordyce
      all nominees        to vote for all        Thomas L. Kempner
         listed           nominees listed           Alix Marduel
          [ ]                  [ ]

        FOR, EXCEPT WITHHOLD AUTHORITY
        to vote for the following nominees only:
        (write the name of the nominee(s) in the space below),


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


2.    To amend the Amended and Restated 1995 Equity Plan to, among other things,
      increase the number of shares issued and issuable under the plan.

      FOR               AGAINST           ABSTAIN

      [ ]                  [ ]               [ ]







3.    To amend the 1998 Employee Stock Purchase Plan to increase the number of
      shares of Common Stock issued and issuable under the plan.

      FOR               AGAINST           ABSTAIN

      [ ]                  [ ]               [ ]


SIGNATURE(S) OF STOCKHOLDER(S) OR AUTHORIZED REPRESENTATIVE(S)

NOTE:    Please date and sign exactly as your name(s) appear(s) hereon. Each
         executor, administrator, trustee, guardian, attorney-in-fact and other
         fiduciary should sign and indicate his or her full title. When stock
         has been issued in the name of two or more persons, all should sign.



         ________________________________________________________
         Signature(s) of Stockholder(s) or Authorized Representative(s)


         Date:  ____________________, 2002