Document:

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                                                                   Exhibit 10.15

                                                     March 12, 2002

Mr. Jeffrey I. Landau
4624 Hillard Avenue
La Canada, CA 91011

Dear Jeff:

     I am pleased to offer you the position of Vice President of Administration
at BioMarin Pharmaceutical Inc., reporting directly to me. You will be
responsible for Information Systems, Human Resources, Real Estate, Facilities
and other duties as required.

     Your starting base salary will be $225,000 per year, payable bi-weekly.

     You will accrue vacation at the rate of four weeks per year and be eligible
to be covered by the Company's medical, dental, and group life insurance plans.

     In addition, the Company will grant you stock options to purchase 125,000
shares of the common stock of BioMarin Pharmaceutical Inc. The exercise price
will be equal to the NASDAQ closing price on your first day of employment. These
options will vest as follows: 6/48ths upon the completion of six months of
employment and 1/48 per month thereafter. The options will expire ten years
after the date of grant. You will receive a detailed Stock Option Agreement in
the coming month.

     Your employment is "at-will." As such, it is terminable by either party
with or without cause. This letter is not to be construed as creating a contract
of employment for any fixed period of time.

Severance Pay

     1.   Voluntary resignation - In the event that you resign or leave the
          Company for any other voluntary reason, or in the event that the
          Company terminates your employment for cause, you will not be eligible
          to receive severance pay under the Company's policy.

     2.   Change of control - In the event that the Company terminates your
          employment for reasons other than cause within one year after a change
          of control, you will be eligible to receive 6 months of base salary
          and immediate vesting of 50% of the then-unvested portion of your
          stock options. All definitions and detailed provisions shall be
          governed by the Company's Change of Control Plan document.

     3.   Termination not related to a Change of Control -

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          a.   Basic severance without a release: In the event that the Company
               terminates your employment for reasons other than cause, not
               change of control-related, you will be eligible to receive
               severance pay, in accordance with the Company's policy, in the
               form of base salary (not employee benefits) continuation for the
               greater of 2 weeks, or 0.5 weeks per full year of service.

          b.   Enhanced severance with a release: The Company will, at the time
               of such termination, offer you an enhanced severance pay package
               equal to 6 months of base salary continuation, as well as
               continue your participation in the Company's medical insurance
               plan for the lesser of 6 months, or upon your participation in
               another employer's plan, in lieu of the basic Company policy on
               severance pay, in consideration for your agreement, at the time
               of such termination, to release the Company from all claims. A
               copy of the release agreement that the Company uses is attached
               only as a sample.

Housing

     1.   For up to a maximum of the first three (3) months of employment, the
          Company will reimburse you for housing (i.e., rent) up to a maximum of
          $2,000 per month, plus airfare to and from Los Angeles up to a maximum
          of the Southwest Airlines rate, plus airport parking.

     2.   Beyond the first three (3) months, the Company will grant you annual
          loans of $24,000 at the approved Company interest rate, if you choose
          to rent. If you choose to purchase a home in the vicinity of Marin
          County, the Company will reimburse you for closing costs you incur on
          the home purchase, and grant you a single loan of up to 20% of the
          purchase price, to a maximum of $100,000, at the approved Company
          interest rate. In either event, repayment of principal and accrued
          interest is to be made by the employee from the profit on BioMarin
          stock options upon the exercise of such options. There is no provision
          for forgiveness, except, in the event of a change of control or an
          involuntary termination of your employment for reasons other than
          cause, in which cases principal and interest will be forgiven, after
          the unused portion of any annual loan for rent is repaid.

     3.   If you leave the Company for any reason, except as a result of a
          change of control or an involuntary termination of your employment for
          reasons other than cause, repayment of principal and accrued interest
          is to be made within 60 days under the rent option, or within 120 days
          under the home purchase option.

     It is an essential condition of this offer that you acknowledge that you
have received, understood and agree to the terms of the BioMarin Proprietary
Information and Inventions Agreement, a copy of which is appended hereto, and
which you agree to sign and execute upon acceptance of this offer.

     This offer of employment is contingent on your providing BioMarin with the
legally required proof of your identity and authorization to work in the United
States.

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     If you accept this offer, you can plan on starting no later than April 1,
2002.

     We are eagerly looking forward to working with you. As you know, this is an
exciting time at BioMarin, and I believe you will find this a challenging and
rewarding experience.

     Please confirm your acceptance of this offer by signing below and returning
to me by March 14, 2002, otherwise this offer will expire on that date.

                                            Sincerely,

                                            /s/ Fredric D. Price
                                            --------------------

                                            Fredric D. Price
                                            Chairman & Chief Executive Officer

Attachments:

     Sample Release Agreement

     BioMarin Proprietary Information and Inventions Agreement

I accept this offer and the conditions stated herein:

/s/ Jeffrey I. Landau
---------------------

Signature

Print Name:  Jeffrey I. Landau
             -----------------

Date: March 13, 2002
      --------------

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              AMENDMENT TO OFFER OF EMPLOYMENT DATED MARCH 12, 2002
              -----------------------------------------------------

This Amendment to the above-mentioned document is entered into as of May 31,
2002 by and between Jeffrey I. Landau and BioMarin Pharmaceutical Inc.

The document is amended as follows:

     1.   The first sentence of Paragraph #2 under "Housing" is amended to read:
          "Beyond the first three (3) months, the Company will grant you annual
          loans of $36,000 at the approved Company interest rate, if you choose
          to rent."

     2.   The following is added to the Offer of Employment: "For purposes of
          this document, 'cause' is defined as (i) any act of personal
          dishonesty taken in connection with a person's responsibilities as an
          employee, (ii) a conviction of or plea of nolo contendre to a felony,
          or (iii) a willful act that constitutes gross misconduct as an
          employee."

ACCEPTED:

/s/ Fredric D. Price                                 June 3, 2002
---------------------                                ------------
Fredric D. Price                                     Date
Chairman & Chief Executive Officer
BioMarin Pharmaceutical Inc.

/s/ Jeffrey I. Landau                                June 1, 2002
-------------------------------------                ------------
Jeffrey I. Landau                                    Date<PAGE>

                                                                   EXHIBIT 10.28

AMENDMENT TO LEASE AGREEMENT
DATED DECEMBER 23, 1996
BY AND BETWEEN
DOUGLAS KAYE, LESSOR
AND
GLYKO, INC., LESSEE
DATED MARCH 15, 2000

The above referenced lease agreement shall be amended as follows:

RENT
----
Commencing April 1, 2000 section 1, "Rent" of the lease agreement shall be
amended as follows:
Year 1: $12,100 per month
Year 2: $12,700 per month
Year 3: $13,300 per month

OPTION TO RENEW
---------------
In the event Lessee has not been in default under any of the terms and
conditions of this lease Lessee shall have two(2), two(2) year options to renew
upon the following term and conditions: Lessee shall give Lessor written notice
of Lessee's intent to exercise its option to renew no earlier than twelve(12)
months and no later than six(6) months prior to the lease expiration date, and
first option to renew period, if exercised.

First Option Period
Year 4: $13,850 per month
Year 5: $14,500 per month

Second Option Period, if exercised
Rent for the second option period shall be determined as follows:

Rent shall be adjusted to the then fair market value for the Premises (the "Fair
Market Value"). Fair Market Value is defined as the rent for Comparable Space
(office and R&D), in new leases signed directly with the respective lessors,
within the previous six(6) months of the exercise of any given option (the
"Comparable Leases"). If there have been no leases signed within such time
period, then Fair Market Value shall be defined as the rent quoted for
Comparable Space (the "Quoted Rent"). The definition of Fair Market Value shall
include annual rent adjustments in the Comparable Leases or Quoted Rent. In no
event shall the rent for any option period be less than the rent paid by Lessee
during the year immediately preceding such option period.

All other terms and conditions of the lease shall remain the same unless as
indicated herein.

Lessor: Glyko, Inc.                          Lessor: Douglas Kaye

By:    /s/ R. W. ANDERSON                    By:    /s/ DOUGLAS KAYE
       -------------------------                    --------------------------
Title: Vice President Finance and            Title:
       -------------------------                    --------------------------
       Administration
       -------------------------
Date:  March 17, 2000                        Date:  March 22, 2000
       -------------------------                    --------------------------

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