Document:

<PAGE>
                                                                   Exhibit 10.48

[CAYMAN CHEMICAL LOGO]                      LEASE EXTENSION - Third Renewal Term

      THIS LEASE EXTENSION is entered into this _21__ day of September, 2002,
between MAXEY, LLC, a Michigan limited liability company, whose address is 1180
East Ellsworth, Ann Arbor, Michigan 48108 ("Landlord"), and ESPERION
THERAPEUTICS, INC., a Delaware corporation, whose address is 3621 South State
Street, 695 KMS Place, Ann Arbor, Michigan 48108 ("Tenant").

                             W I T N E S S E T H:

      WHEREAS, the parties hereto have entered into a certain lease dated
January 4, 1999 for the vivarium annex to the building owned by Landlord at 1180
East Ellsworth Road, Pittsfield Township, Washtenaw County, Michigan, containing
approximately 5,150 square feet of space (the "Lease").

      NOW, THEREFORE, in consideration of the terms, conditions and covenants
hereinafter set forth to be paid, kept and performed by Landlord and Tenant, the
parties hereto agree as follows:

      Pursuant to Section 2, it is mutually agreed that the lease is hereby
extended for an additional one (1) year period (the second "Renewal Term").
Tenant will pay to the Landlord rent at the rate of Sixteen thousand, two
hundred and fifty ($16,250.00) dollars commencing on January 1, 2003 and
continuing on the first day of each and every month thereafter for the next
succeeding twelve (12) months.

      All other terms and conditions of the Lease remain in full force and
effect.

LANDLORD * * *                                  TENANT * * *

MAXEY, LLC                                      ESPERION THERAPEUTICS, INC.

By: /s/ Kirk M. Maxey, M.D.                     By: /s/ Roger S. Newton
   ---------------------------------                ----------------------------
       Kirk M. Maxey, M.D.                            Roger S. Newton, Ph.D.
       Its President                                  Its President

Date:  10-22-02                                 Date:   10-23-02
     -------------------------------                  --------------------------<PAGE>
                                                                   EXHIBIT 10.49

                                                                   June 26, 1998

Roger Newton, Ph.D.
1425 Bardstown Trail
Ann Arbor, MI 48105

                                    Re:  "Esperion Therapeutics, Inc."

Dear Roger,

On behalf of the founders and prospective venture investors of Esperion
Therapeutics, Inc. (hereinafter, "Esperion" or "The Company"), I am very pleased
to propose a means of working with you in the organization of the Company and
for recruiting you to be the CEO. The following represent a series of proposed
terms:

     1.  The position is President, Chief Executive Officer, and a member of the
         Board of Directors of the Company.

     2.  Cash compensation will consist of a base salary of $200,000 per year
         plus a bonus of up to 30% of the base salary. The magnitude of the
         bonus, if any, will be determined by the Company's Board of Directors,
         based upon achievement of a series of mutually agreed upon performance
         milestones. A proposed series of milestones is contained in Exhibit A
         to this letter.

     3.  A benefits package will be provided to you which is equivalent to that
         offered to any other member of the senior management team of the
         Company, including health benefits. The details of the benefits package
         will be worked out between you, other members of the startup management
         team, and the Company's Board of Directors.

     4.  A performance review will be conducted on an annual basis, which will
         include a determination of potential adjustment of base salary, along
         with bonus. Also to be considered by the Board of Directors on an
         annual basis will be the grant of incentive stock options, in
         recognition of your performance for the preceding year.

     5.  You will be provided 800,000 shares of common stock, representing 20%
         of the Company's outstanding stock prior to the infusion of venture
         capital (i.e., 4 million shares) inclusive of a pool of as yet
         unallocated shares (i.e., management pool) which is satisfactory in
         magnitude to the Company's prospective investors. You will acquire
         these shares in the form of founder's stock, purchased at $0.001 per
         share. These shares will be subject to a repurchase agreement between
         you and the Company, which provides for the functional equivalent of a
         four-year vesting schedule. These shares will be subject to repurchase
         by the Company at your cost, with such right lapsing ratably on a
         quarterly basis over four years (i.e., at a rate of 50,000 shares per
         quarter).

     6.  As a means of assisting you in your tax liability associated with the
         exercise of your WLA options, the Company will provide you with a one
         time signing bonus of 25% of the value of your tax liability in cash,
         and a loan in the amount of 25% of the value of your tax liability. The
         remaining 50% of the tax obligation, in any event, will be your
         responsibility. The loan will be for four years, bearing an interest
         rate of 1% over prime, with one fourth of the aggregate principal and
         interest payments forgiven on each anniversary of your employment
         subject to your continued employment with the Company. If your
         employment with the Company is terminated, all of the remaining
         principal and accrued interest on the outstanding balance will be
         due immediately.

<PAGE>

     7.  In the event that your employment with the Company is terminated by the
         Company for reasons other than cause, you will be provided a severance
         package of 6 months of salary, with continuation of benefits during
         this period, and the Company will provide accelerated vesting such that
         25% of your as yet unvested founders' stock and options will
         immediately vest. In the event that you become disabled with a
         catastrophic illness, or decease while a full-time employee of the
         Company, you will receive the same continuation of salary and benefits
         for your family, along with the accelerated vesting of the 25% of the
         aggregate of your then unvested founders' stock and options. If you
         terminate your employment with the Company voluntarily, you will
         forfeit the severance package, as well as any of your unvested stock,
         or stock options. With respect to any vested options, in the event that
         you voluntarily terminate your employment with the Company, you will
         have 90 days to exercise these options, or otherwise they will be
         forfeited.

     8.  You will be asked to execute a standard confidentiality and patent
         assignment agreements. You will also agree that in the event that you
         sever your relationship with the Company, for a period of 12 months,
         you will not engage in professional activity which will be directly
         competitive with the business of the Company (anti-atherosclerosis drug
         discovery and development). In the event of involuntary termination for
         other than cause, your non-compete obligation will be waived.

If the terms of this proposal are acceptable, please so indicate by executing on
the line provided below.

I look forward to working with you on building a successful venture which will
be a dominant player in the development of therapeutic agents which can safely
and effectively intervene in atherosclerosis, and related metabolic diseases.

                                   Sincerely,

                                   David I. Scheer

cc:  Annie Lamont/Oak Investment Partners
     Christopher Moller/TL Ventures

ACCEPTED AND AGREED TO:

/s/ Roger S. Newton             7/6/98
--------------------------------------
Roger Newton, Ph.D.               Date
<PAGE>

                             Appendix A. Milestones

 1.     Complete an updated business plan.

 2.     Complete the recruitment of key members of the startup management team.

 3.     Identify and secure in the form of lease and improvements, facilities
        for the Company.

 4.     Complete the initial financing of the Company.

 5.     Recruit a finance and administration resource, and install financial
        controls and reporting system.

 6.     Demonstrate diligence on the development plan of the Company's lead
        product.

 7.     Identify and integrate other desirable projects which are of value
        either in product, technology, or business development.

 8.     Prepare and achieve ratification of a business development strategy.

 9.     Secure a corporate partner for one or more projects.

10.     Identify and recruit members of the Company's Scientific Advisory Board.

11.     Identify and recruit (if needed) additional outside Board members.<PAGE>
                                                                   EXHIBIT 10.50

                                                               November 24, 1998

Timothy M. Mayleben
1728 Snowberry Ridge Rd.
Ann Arbor, MI 48103

Dear Tim,

On behalf of Esperion Therapeutics, Inc. (hereinafter "Esperion" or "The
Company"), I am pleased to offer you a position in the Company. The following
represents a series of proposed terms:

     1.  The position is Vice President, Finance and Administration and Chief
         Financial Officer.

     2.  Cash compensation will consist of a base salary of $130,000 per year
         plus a bonus of up to 20%. Bonus eligibility begins only after one year
         of satisfactory employment. The magnitude of the bonus, if any, will be
         determined by the Company's Board of Directors, based upon achievement
         of a series of mutually agreed upon performance milestones. A proposed
         series of milestones will be developed between you and the
         President/CEO.

     3.  A benefit package will be provided to you which is equivalent to that
         offered to other staff members employed by the company, including
         health benefits.

     4.  A performance review will be conducted on an annual basis, which will
         include a determination of potential adjustment of base salary, along
         with bonus when eligible. Also to be considered on an annual basis will
         be the grant of incentive stock options, in recognition of your
         performance for the preceding year.

     5.  As an incentive, you will be granted an option to purchase 90,000
         shares of the Company's common stock, exercisable at a price per share
         equivalent to the fair market value of common stock ($0.15 per share).
         These options will vest quarterly over a four-year period of time from
         the date of issuance, and be exercisable for 4 years.

     6.  In the event that your employment with the Company is terminated by the
         Company for reasons other than cause (cause shall be defined as (i) any
         action by Employee involving willful gross misconduct having a material
         adverse effect on the Company; (ii) Employee being convicted of a
         felony under the laws of the US or any state or under the laws of any
         other country or political subdivision thereof), you will be provided a
         severance package of 6 months of salary, with continuation of benefits
         during this period, and the Company will provide accelerated vesting
         such that 25% of

<PAGE>

                                       - 2 -                   November 24, 1998

         your as yet unvested stock options will immediately vest. In the event
         that your employment with the Company is terminated due to death or
         "permanent and total disability" (as such term may be defined by the
         Company's insurer) the company will provide accelerated vesting such
         that 25% of your yet unvested stock options will immediately vest. If
         you terminate your employment with the Company voluntarily, you will
         forfeit the severance package, as well as any of your unvested stock
         options. With respect to any vested options, in the event that you
         voluntarily terminate your employment with the company, you will have
         90 days to exercise these options, or otherwise they will be forfeited.

     7.  You will be asked to execute a standard confidentiality and assignment
         agreement, as well as a standard non-compete agreement. The non-compete
         agreement will provide that in the event that you sever your
         relationship with the Company, for a period of 12 months, you will not
         engage in professional activity which will be directly competitive with
         the business of the Company (anti-atherosclerosis drug discovery and
         development). In the event of involuntary termination for other than
         cause, your non-compete obligation will be waived.

     8.  If the above terms are agreeable, your start date will be January 11,
         1999.

If the terms of this proposal are acceptable, please so indicate by executing on
the line provided below, and Fax as well as mail (an original copy) to Esperion.
Please respond to this proposal within two weeks from the date of this offer.
After this date (i.e. after 12/09/98), this offer may be withdrawn at the
discretion of Esperion Therapeutics. I look forward to working with you.

                                   Sincerely,

                                   Roger S. Newton, Ph. D.
                                   President/CEO

cc:  Annie Lamont, Christopher Moller,
     David  Scheer, Anders Wiklund

ACCEPTED AND AGREED TO:

 /s/ Timothy M. Mayleben                   11-25-98
---------------------------------------------------
Timothy M. Mayleben                            Date

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00048-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00048-of-00352.parquet"}], [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00048-of-00352.parquet"}]]