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                                                                   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

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                                       - 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
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Timothy M. Mayleben                            Date