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                                                                Exhibit 10.30

                         EXECUTIVE EMPLOYMENT AGREEMENT

     This Executive Employment Agreement (this "Agreement") is dated as of
February 9, 2002 by and between Genzyme Transgenics Corporation ("GTC", and
together with its controlled affiliates and subsidiaries, the "Company"), a
Massachusetts corporation with its principal executive offices at 175 Crossing
Boulevard, 4th Floor, Suite 410, Framingham, MA 01702-9322; and Paul K. Horan
("Executive").

                                    ARTICLE 1
                             EMPLOYMENT OF EXECUTIVE

     1.1    EMPLOYMENT. Subject to the terms and conditions of this Agreement,
the Company agrees to employ Executive in a full time capacity to serve as an
executive in the corporate development activities of GTC as Senior Vice
President of Corporate Development and to perform such specific duties as may
reasonably be assigned to Executive from time to time by the Chief Executive
Officer of GTC for the period commencing on March 11, 2002 (the "Effective
Date") and continuing until terminated as herein expressly provided. Executive
hereby accepts such employment for the term hereof.

     1.2    NO CONFLICTING COMMITMENTS. During the period of Executive's full
time employment with the Company, Executive will not undertake any commitments
which might materially impair Executive's performance of his duties as a full
time employee of the Company. Notwithstanding anything herein to the contrary
the Executive shall have the right to continue to serve on the Board of
Directors of GeneMatrix, Inc., and may from time to time serve on such other
boards of directors, or boards of trustees, of both for-profit and
not-for-profit organizations, provided that such organizations are not directly
competitive with the business of GTC and such service does not materially impair
Executive's performance of his duties hereunder.

                                    ARTICLE 2
                                  COMPENSATION

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

     2.1    BASE SALARY. From the Effective Date through December 31, 2002, the
Company shall pay to Executive a base salary (the "Base Salary") of $10,833.33
biweekly (equivalent to an annual rate of $260,000), prorated during the period
Executive is employed hereunder and payable in substantially equal installments
in accordance with GTC payroll practice as in effect from time to time. With
respect to subsequent periods during the term of this Agreement, the
Compensation Committee of the Board of Directors of GTC (the "Committee) will
review Executive's base salary and other compensation from time to time and may
make adjustments to such base salary and determine such bonus based upon, among
other factors: (a) Executive's performance, (b) GTC's performance, (c) changes
in costs of living, (d) changes in Executive's responsibilities, and (e) the
benefit to GTC of Executive's efforts on its behalf; provided that

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Executive's base salary shall not be less than $260,000 per year during the term
of this Agreement.

     2.2    SIGN-ON BONUS. Executive shall be entitled to receive a one-time
cash bonus (the "Sign-On Bonus") of $25,000 upon completion of thirty (30) days
of employment. The Sign-On Bonus shall be paid to Executive on the first pay
period following the Executive's completion of such 30-day period.

     2.3    ANNUAL BONUS. In addition to the Base Salary and Sign-On Bonus,
Executive shall be eligible to earn an annual cash incentive bonus of up to
twenty-five percent (25%) of Executive's then current Base Salary on an
annualized basis, based on (a) Executive's achievement of certain individual and
corporate objectives established jointly by the Chief Executive Officer and
Executive and (b) GTC's performance. Such cash bonus, if earned, will be payable
to Executive annually within one hundred twenty (120) days after the end of the
calendar year for which it is earned.

     2.4    STOCK OPTIONS. GTC will grant to Executive options (the "Options")
to purchase 50,000 shares of GTC's Common Stock, $0.01 par value per share,
under GTC's 1993 Equity Incentive Plan (the "Plan"), at a price per share equal
to the opening price of GTC's Common Stock on the later of February 14, 2002 or
the date Executive commences employment with GTC. The Options shall be
exercisable immediately as to 20% of the shares and as to an additional 20% on
each of the next four (4) anniversaries of the date Executive commences
employment with the Company. The Options shall have a term of ten (10) years
following the date of grant, subject to early termination in the event of
termination of Executive's employment in accordance with this Agreement and the
Plan, and such other terms and conditions consistent with the form of stock
option certificate most recently approved by the Board or any authorized
committee thereof for use under the Plan or as the Board or any such committee
may hereafter direct. The Options granted to Executive shall be incentive stock
options ("ISOs") under Section 422 of the federal Internal Revenue Code of 1986,
as amended from time to time (the "Code"), to the maximum extent permitted by
law. In the event that the Options granted to Executive are in an amount greater
than the maximum permitted by such Section 422 to obtain ISO treatment, the
Company will work in cooperation with Executive to designate a portion of the
Options as ISOs and the remainder as non-qualified stock options.

     2.5    PARTICIPATION IN FUTURE EQUITY INCENTIVE PLANS. Executive shall be
entitled to participate, to the extent and in the manner determined by GTC's
Board of Directors in its absolute discretion, in any stock option, stock
purchase or other equity incentive plan established by the Company from time to
time, it being the understanding of the Company and Executive that such
participation would be for the purpose of providing Executive additional
opportunities for equity participation in the Company.

     2.6    FRINGE BENEFITS. In addition to Executive's base salary and bonus,
Executive shall be entitled to participate in all employee benefit plans or
programs of GTC. GTC does not guarantee the adoption or continuance of any
particular employee benefit or stock plan or other program during the term of
this Agreement, and Executive's participation in any such plan or program shall
be subject to the provisions, rules and regulations applicable thereto.
Executive shall be entitled to four (4) weeks paid vacation each year in
accordance with applicable Company policy. Health and dental plans shall cover
Executive and his dependents as they do for

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other GTC executives. Such health and dental plans comply with ERISA and COBRA
to the extent applicable. Under current health insurance policies, such COBRA
rights will commence on termination of the period over which severance payments
are made under Section 3.2.

     2.7    RELOCATION AND OTHER EXPENSES.

            (a)     The Company shall reimburse Executive for actual
out-of-pocket expenses incurred in connection with Executive's relocation from
Pennsylvania to Massachusetts, including but not limited to travel costs to and
from Pennsylvania, costs of shipping household goods and two automobiles, and
real estate closing costs on the sale of Executive's home in Pennsylvania and
the purchase of a new home in Massachusetts; provided that (i) such expenses are
incurred not later than twelve (12) months after Executive's commencement of
employment with the Company and (ii) the Company shall have no obligation to
reimburse any such relocation expenses to the extent they exceed, in the
aggregate, $75,000. To the extent Executive incurs federal or state tax
liability in connection with his receipt of such relocation reimbursement, the
Company shall provide Executive with a "gross-up" payment to cover such tax
liability, but only to the extent that any such gross-up payment and relocation
expenses paid, in the aggregate, do not exceed $75,000.

            The Company shall reimburse Executive for up to an aggregate of
$30,000 of temporary living expenses, including, without limitation, (i)
reasonable temporary living costs for Executive within the twelve (12) month
period after the Effective Date, which costs may include hotel accommodations,
or a furnished apartment in Massachusetts and (ii) travel expenses incurred by
Executive for travel to and from his current home; provided that such costs are
incurred on or before twelve (12) months after the Effective Date or such
earlier date as Executive purchases a home in Massachusetts. To the extent
Executive incurs federal or state tax liability in connection with his receipt
of such temporary living reimbursement, the Company shall provide Executive with
a "gross-up" payment to cover such tax liability, but only to the extent that
any such gross-up payment and temporary living expenses paid, in the aggregate,
do not exceed $30,000.

            The Company shall reimburse Executive for the foregoing expenses and
all ordinary and necessary business expenses incurred in the performance of
Executive's duties under this Agreement, provided that Executive accounts
properly for such expenses to the Company in accordance with the general
corporate policies of the Company and in accordance with the requirements of the
Internal Revenue Service regulations under the Code relating to substantiation
of expenses.

                                    ARTICLE 3
                                   TERMINATION

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

            (a)     Executive's employment hereunder shall terminate upon
Executive's death or inability, by reason of physical or mental impairment, to
perform substantially all of Executive's duties as contemplated herein for a
continuous period of one hundred twenty (120) days or more;

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            (b)     The termination of Executive's employment hereunder for
Cause by the Chief Executive Officer of GTC, at his or her option, to be
exercised by delivery of written notice to Executive;

            (c)     The termination of Executive's employment hereunder by the
Chief Executive Officer of GTC, at his or her option, without Cause, to be
exercised by delivery of written notice to Executive; or

            (d)     The termination of Executive's employment hereunder by
Executive to be exercised by delivery of thirty (30) days prior written notice
from Executive to the Company, other than for Good Reason; or

            (e)     The termination of Executive's employment hereunder by
Executive, at his option, if the Company breaches any material duty or
obligation hereunder and such breach is continuing and has not been waived by
Executive (i) more than thirty (30) days after written notice of such breach has
been given by Executive to the Board of Directors of GTC and (ii) as of the date
notice of termination is given.

     For purposes of this Agreement, "Cause" shall mean (i) Executive's breach
of any material duty or obligation hereunder after written notice of such breach
has been given to the Executive by the Board of Directors and such breach shall
have continued for thirty (30) days after receipt of such notice, or intentional
or grossly negligent conduct that is materially injurious to GTC, as reasonably
determined by GTC's Board of Directors, or (ii) willful failure to follow the
reasonable directions of GTC's Board of Directors after written notice of such
failure has been given to the Executive by the Board of Directors and such
failure shall have continued for thirty (30) days after receipt of such notice.

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

            (a)     If Executive's employment with the Company or its successor
in interest terminates pursuant to Sections 3.1(a), 3.1(b), or 3.1(d): (i) all
payments and benefits provided to Executive under this Agreement shall cease as
of the date of termination of employment and Executive shall be entitled to
receive any unpaid Base Salary accrued through the date, plus credit for any
vacation earned but not taken and the amount, if any, and any bonus awarded for
the past fiscal year which has not yet been paid to Executive; and (ii) all
further vesting on all stock options to purchase Common Stock of GTC then held
by Executive on that date shall immediately cease as of the date of termination
of employment and thereafter such stock options shall be exercisable by
Executive in accordance with their respective terms.

            (b)     If Executive's employment with the Company or its successor
in interest terminates pursuant to Section 3.1(c) or 3.1(e), Executive shall be
entitled to the benefits provided in Section 4.2 hereof.

                                    ARTICLE 4
                     TERMINATION FOLLOWING CHANGE IN CONTROL

     4.1    TERMINATION OF EMPLOYMENT FOLLOWING CHANGE IN CONTROL. If a Change
in Control of the Company shall have occurred, Executive shall be entitled to
the benefits provided

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in Section 4.2 hereof upon the subsequent termination of Executive's employment
within twelve (12) months after the effective date of such Change in Control,
unless such termination is (a) because of Executive's death or Retirement,
(b) by the Company for Cause or (c) by Executive other than for Good Reason. For
purposes of this Agreement:

            (a)     "Change in Control of the Company" shall mean:

                    (i)     the acquisition (A) by any "person" (as such term is
defined in Section 3(a)(9) of the Securities Exchange Act of 1934) or (B) by
Genzyme Corporation, from any party of an amount of GTC's Common Stock so that
it holds or controls 50% or more of GTC's Common Stock;

                    (ii)    a merger or similar combination after which 49% or
more of the voting stock of the surviving corporation is held by persons who
were not stockholders of GTC immediately prior to such merger or combination;

                    (iii)   the election by the stockholders of GTC of 50% or
more of the directors of GTC other than pursuant to nomination by GTC's
management; or

                    (iv)    the sale by the Company of all or substantially all
of its assets or business.

            (b)     "Good Reason" shall mean termination by Executive after a
Change in Control upon:

                    (i)     the assignment of any duties to Executive
inconsistent with Executive's position, duties and responsibilities with the
Company immediately prior to the Change in Control, or any removal of Executive
from or any failure to re-elect Executive to any of such positions except in
connection with the termination of Executive's employment for Cause or
Retirement or as a result of Executive's death or by Executive other than for
Good Reason, each without Executive's express written consent;

                    (ii)    a reduction by the Company in Executive's Base
Salary as in effect on the date hereof or as the same may be increased from time
to time;

                    (iii)   the Company's requiring Executive to be based
anywhere other than within sixty (60) miles of Executive's office location
immediately prior to the Change in Control, except for required travel on the
Company's business to an extent substantially consistent with Executive's
business travel obligations in the twelve (12) months immediately prior to the
Change in Control without Executive's express written consent; or

                    (iv)    the failure by the Company to obtain the assumption
of the agreement to perform this Agreement by any successor as contemplated in
Section 6.3 hereof.

            (c)     "Retirement" shall mean termination of Executive's
employment in accordance with GTC's retirement policy, including early
retirement, generally applicable to its salaried employees.

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     4.2    PAYMENTS UPON TERMINATION WITHOUT CAUSE, FOR GOOD REASON, FOLLOWING
CHANGE IN CONTROL. In addition to, and not in limitation of, the provisions of
Article 3, if, within twelve (12) months after a Change in Control of the
Company, Executive's employment is terminated (a) by the Company or its
successor in interest other than for Cause or Retirement or (b) by Executive for
Good Reason, then Executive shall be entitled to the benefits provided below:

            (a)     BACK SALARY PAYMENT. The Company shall pay Executive any
unpaid Base Salary accrued through the date of termination at the rate in effect
at the time notice of termination is given, plus credit for any vacation earned
but not taken and the amount, if any, and any bonus awarded for the past fiscal
year which has not yet been paid to Executive;

            (b)     SEVERANCE PAYMENT. The Company shall pay Executive an
aggregate severance payment equal to (i) eighteen (18) months of Base Salary in
effect on the date of termination and (ii) an amount equal to Executive's
maximum incentive bonus that would next be payable to him and would otherwise be
due to Executive if such termination had not occurred and the maximum amount of
such bonus had been fully earned, pro rated on the basis of the number of days
that have elapsed between the beginning of the bonus period in which such
termination occurs and the date of termination (the "Severance Amount"), which
Severance Amount shall be payable in substantially equal monthly installments
over a 18-month period following the date of termination;

            (c)     CONTINUATION OF BENEFITS. The Company shall maintain in full
force and effect, for Executive's continued benefit until the earlier of (a) the
end of the 18th calendar month following the date of termination of employment
or (b) Executive's commencement of full time employment with a new employer, all
life insurance, medical, health and accident insurance, and disability plans,
programs or arrangements in which Executive was entitled to participate
immediately prior to the date of termination, provided that Executive's
continued participation is possible under the general terms and provisions of
such plans and programs. In the event that Executive's participation in any such
plan or program is barred, the Company shall arrange to provide Executive with
benefits substantially similar to those which Executive was entitled to receive
under such plans and programs at its expense; and

            (d)     ACCELERATED VESTING OF STOCK OPTIONS. Any stock options to
purchase Common Stock of GTC then held by Executive on the date of termination
which are then subject to vesting shall, notwithstanding any contrary provision
in this Agreement or the Plan pursuant to which such options had been granted,
become fully vested and exercisable on the date of termination, and such stock
options shall remain exercisable by Executive for a period of eighteen (18)
months after the date of termination. Executive acknowledges that any incentive
stock options exercised more than ninety days after the date of termination
shall no longer qualify as incentive stock options under the Code.

     4.3    LIMITATION ON BENEFIT PAYMENTS. The benefits payable under this
Agreement are subject to the limitation that, when added to the aggregate
present value of any other payments in the nature of compensation to Executive
which are contingent on a Change of Control within the meaning of Section
280G(b)(2)(A)(i) of the Code, they may not exceed 2.99 times the "base amount"
as defined in Section 280G(b)(3)(a) of the Code.

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                                    ARTICLE 5
                  CONFIDENTIAL INFORMATION AND NON-COMPETITION

     As a condition to the Company's obligations hereunder, Executive will
execute a confidentiality and non-competition agreement pertaining to the
intellectual property and confidential information of the Company and the
Company's standard form of non-competition provision for executive officers and
key employees. The obligations of Executive under this Article 5 and the
agreements referenced in this paragraph shall survive termination of this
Agreement for any reason.

                                    ARTICLE 6
                                  MISCELLANEOUS

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

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

     6.3    ASSIGNMENT. This Agreement may not be assigned, in whole or in part,
by any party without the prior written consent of the other party, except that
GTC may, without the consent of Executive, assign its rights and obligations
under this Agreement to any corporation, firm or other business entity with or
into which GTC may merge or consolidate, or to which GTC may sell or transfer
all or substantially all of its assets, or of which 50% or more of the equity
investment and of the voting control is owned, directly or indirectly, by, or is
under common ownership with, GTC. After any such assignment by GTC, GTC shall be
discharged from all further liability hereunder and such assignee shall have all
the rights and obligations of GTC under this Agreement.

     6.4    ENTIRE AGREEMENT. This Agreement is the entire agreement of the
parties with respect to the subject matter hereof and supersedes any prior
agreement or understanding relating to Executive's employment with or
compensation by the Company.

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

            If to the Company, to:

                    Genzyme Transgenics Corporation
                    175 Crossing Boulevard
                    4th Floor, Suite 410
                    Framingham, MA 01702-9322
                    Attention: Chief Executive Officer

                    with a copy to:

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                    Nathaniel S. Gardiner, Esq.
                    Palmer & Dodge LLP
                    111 Huntington Avenue at Prudential Center
                    Boston, Massachusetts 02199-7613

            If to Executive, to:

                    Paul K. Horan, Ph.D. at his then current address on the
                    payroll records of the Company;

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

     6.6    AMENDMENTS. This Agreement may be amended, supplemented or otherwise
modified at any time, but only by an instrument in writing signed by the parties
hereto.

     6.7    GOVERNING LAW. This Agreement and the legal relations among the
parties hereto shall be governed by and construed in accordance with the laws of
the Commonwealth of Massachusetts, without regard to its conflict of law
provisions.

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

     6.9    SURVIVAL. Articles 5 and 6 shall survive the termination of this
Agreement for the periods of time indicated therein or indefinitely if no period
of time is indicated.

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

                                 EXECUTIVE:


                                  /s/ Paul K. Horan
                                 ---------------------
                                 Paul K. Horan


                                 COMPANY:

                                 GENZYME TRANSGENICS CORPORATION


                                 By:  /s/ Geoffrey F. Cox
                                     -------------------------------------------
                                     Geoffrey F. Cox
                                     President and Chief Executive Officer

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