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                                                                   EXHIBIT 10.1

                          ESPERION THERAPEUTICS, INC.

                            1998 STOCK OPTION PLAN
                            ----------------------


1.   PURPOSE.
     -------

          The purpose of the Esperion Therapeutics, Inc. 1998 Stock Option Plan
(the "Plan') is to further the growth and success of Esperion Therapeutics, Inc.
(the "Company") by attracting and retaining the services of directors, officers,
selected employees, consultants and advisors by enabling them to acquire shares
of the Company's Common Stock, par value $.001 per share (the "Common Stock").
Except where the context otherwise requires, the term "Company" shall include
the parent corporation and all subsidiary corporations, if any, of the Company
as defined in Sections 424(e) and 424(f) of the Internal Revenue Code of 1996,
as amended (the "Code").
                 ----

2.   TYPES OF OPTIONS.
     ----------------

          Options granted under the Plan may be either "incentive stock options"
("ISOs"), intended to qualify as such under the provisions of Section 422 of the
  ----
Code, or "non-qualified stock options" not intended to qualify as ISOs under
Section 422 of the Code.

3.   ADMINISTRATION:
     --------------

          (a)  Board of Directors/Committee.
               ----------------------------

          Options under the Plan shall be granted, and the Plan shall be
initially administered, by the Board of Directors of the Company (the "Board")
                                                                       -----
and, upon designation by the Board, by a committee (the "Committee") consisting
                                                         ---------
of two or more members of the Board. The members of the Committee shall be
appointed, and may be removed it any time with or without cause, by resolution
adopted by the Board. Any vacancy on the Committee, whether due to action of the
Board or any other cause, shall be filled by resolution adopted by the Board.
Any reference hereinafter to the "Committee" shall be deemed to be a reference
                                  ---------
to the Board until the Committee shall have been designated by the Board.

          (b)  Procedures.
               ----------

          The Committee shall select from among its members a Chairman and may
adopt such rules and regulations as it shall deem appropriate concerning the
holding of meetings and the administration of the Plan. A majority of the entire
Committee shall constitute a quorum and the action of a majority of the members
of the Committee present at a meeting at which a quorum is present, or an action
approved in writing by all of the members of the Committee, shall be the act of
the Committee.

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          (c)  Interpretation.
               --------------

          The Committee shall have full power and authority to interpret the
provisions of the Plan and any Option Agreement (as defined in Section 6(c)
below), to prescribe, amend and rescind rules and regulations relating to the
Plan and to resolve all questions arising under the Plan. All decisions of the
Committee shall be conclusive and binding on all participants in the Plan.

4.   SHARES OF STOCK SUBJECT TO THE PLAN.
     -----------------------------------

          (a)  Numbers of Shares.
               -----------------

          Subject to the provisions of Section 11 below (relating to adjustments
upon changes in capital structure), the number of shares of Common Stock
available for sale upon exercise of options granted under the Plan shall not
exceed 1,320,000 shares. If and to the extent that options granted under the
Plan terminate, expire or are cancelled without having been fully exercised, new
options may be granted under the Plan with respect to the shares of Common Stock
covered by the unexercised portion of such terminated, expired or cancelled
options, all of which may be granted as ISOS.

          (b)  Character of Shares.
               -------------------

The shares of Common Stock issuable upon exercise of an option granted under the
Plan may be (i) authorized but unissued shares of Common Stock, (ii) shares of
Common Stock held in the Company's treasury, or (iii) a combination of both.

          (c)  Reservation of Shares.
               ---------------------

          The number of shares of Common Stock reserved by the Company for
issuance under the Plan shall at no time be less than the maximum number of
shares which may be purchased at any time pursuant to outstanding options.

5.   ELIGIBILITY.
     -----------

Options may be granted under the Plan only to Persons Who are directors,
officers, employees or advisors to the Company at the time of grant options
granted to officers and employees of the Company shall be, in the discretion of
the Committee, either ISOs or NSOs, and options granted to directors who are not
employees of the Company and to consultants and advisors shall be NSOs.
Notwithstanding anything herein to the contrary, ISOs shall only be granted to
those persons who qualify as an employee under Section 3401(c) of the Code.

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6.   GRANT OF OPTIONS.
     ----------------

          (a)  General.
               -------

          Options may be granted under the Plan at any time and from time to
time on or prior to the Expiration Date (as defined in Section 15 below).
Subject to the provisions of the Plan, the Committee may, in its discretion,
determine.

               (i)   the persons (from among the class of persons eligible under
               Section 5 above to receive options under the Plan) to whom
               options shall be granted (the "Optionees");
                                              ---------

               (ii)  the time or times at which options shall be granted;

               (iii) the number of shares subject to each option;

               (iv)  the Option Price (as defined in Section 7 below) of the
               shares subject to each option, which price, in the case of ISO's,
               shall be not less than the minimum specified in Section 7 below;

               (v)   the time or times when each option shall become exercisable
               and the duration of the exercise period; and

               (vi)  any restrictions on the sale of, and any repurchase rights
               with respect to, shares purchased upon exercise of an option, as
               contemplated by Section 13 below,

          (b)  Date of Grant.
               -------------

          The date of grant of an option under the Plan shall be the date on
which the Committee approves the grant.

          (c)  Option Agreements.
               -----------------

          Each option granted under the Plan shall be designated as an ISO or an
NSO and shall be subject to the and conditions applicable to ISOs or NSOs (as
the case may be) set forth in the Plan, and each option shall be evidenced by a
written agreement (an "Option Agreement"), containing such terms and conditions,
                       ----------------
not inconsistent with the Plan, as the Committee may, in its discretion,
determine. Each Option Agreement shall be executed by the Company and the
Optionee. Option Agreements may differ among Optionees.

          (d)  No Evidence of Employment.
               -------------------------

          Neither the grant of an option nor any provision of the Plan or any
Option Agreement shall confer upon any (Optionee any right with respect to the
continuation of

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his or her employment by, or his or her consulting or advisory relationship to,
the Company or interfere in any way with the right of the Company at any time to
terminate such employment or relationship or, in the case of employees
(including officers), to increase or decrease the compensation of the Optionee
from the rate in existence at the time of the grant of an option.

7.   OPTION PRICE.
     ------------

The price (the "Option Price") at which each share of Common Stock subject to an
                ------------
option granted under the Plan may be purchased shall be determined by the
Committee at the time the option is granted; provided, however, that in the case
of an ISO, such Option Price shall in no event be less than one hundred percent
(100%) of the fair market value of such share of Common Stock at the time of
grant, as determined by the Committee and, in the case of a ten percent (10%)
owner (see Section g(c) below, such Option Price shall be at least one hundred
ten percent (110%) of the fair market value of the stock subject to such
options.

8.   EXERCISE OF OPTIONS.
     -------------------

          (a)  General.
               -------

          Each option shall be exercisable, in whole or in part, at such time or
times, or within such period or periods, or upon the occurrence of such event or
events, as shall be determined by the Committee and set forth in the Option
Agreement evidencing such option. If an option is not at the time of grant
immediately exercisable full, the Committee may (i) in the Option Agreement
evidencing such option provide for the acceleration of the exercise date or
dates of such option, in whole or in part, upon the occurrence of specified
events, or (ii) at any time prior to the complete expiration of an option,
accelerate, in whole or in part, the exercise date or dates of such option.

          (b)  Restrictions on Exercise.
               ------------------------

               (i)   No option by its terms shall be exercisable after the
               expiration of ten years from the date such option is granted.

               (ii)  No option may be exercised at a time when the exercise
               thereof or the issuance or transfer of shares upon such exercise
               would, in the opinion of the Committee, constitute a violation of
               any law, federal, state, local or foreign, or any regulations
               thereunder, or the requirements of the New York Stock Exchange or
               any other national securities exchange or market.

               (iii) The Committee, in its discretion, may require an Optionee
               to (A) represent in writing that the shares of Common Stock to be
               received upon exercise of an option are being acquired for his or
               her own account for investment and not with a view to
               distribution
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               thereof, nor with any present intention of distributing the same,
               and (B) make such other representations and warranties as are
               deemed necessary by counsel to the Company. Stock certificates
               representing shares of Common Stock not registered under the
               Securities Act of 1933, as amended (the "1933 Act"), acquired
                                                        --------
               upon the exercise of options shall bear the following legend:

"THESE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR
INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, OR ANY STATE SECURITIES LAW. THESE SECURITIES MAY NOT BE SOLD OR
TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR ANY EXEMPTION THEREFROM UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE SECURITIES LAW."

               (iv)  No option may be exercised for any fractional share.

          (c)  Limitation of Exercise of ISOs.
               ------------------------------

To the extent that the aggregate fair market value (as determined by the
Committee as of the time the options with respect to such stock were granted) of
stock with respect to which options intended to be ISOs are exercisable for the
first time by an Optionee during any calendar year (under all plans of the
Company) exceeds $100,000, such options shall be treated as NSOs. An ISO may not
be granted to an individual who at the time an option is granted, owns stock
that has more than ten percent (10%) of the voting power of all classes of stock
of the Company ("ten percent (10%) owner"). An individual is considered as
                 -----------------------
owning stock, for purposes of the previous sentence, owned directly or
indirectly by or for his brothers, sisters, spouse, ancestors and lineal
descendants. An individual is also deemed to own stock held by a foreign or
domestic corporation, partnership, trust or estate for which the individual is a
shareholder, partner or beneficiary proportionately to his interest in the
corporation, partnership, trust or estate as a shareholder, partner or
beneficiary. Notwithstanding the foregoing prohibition on a "ten percent (10%)
owner," an ISO may be granted to a "ten percent (10%) owner" if (i) the ISO so
granted is not exercisable after the expiration of five (5) years from the date
of grant and (ii) the Option Price of such ISO is at least one hundred ten
percent (110%) of the fair market value of the stock subject to the ISO (as
provided in Section 7 hereof).

9.   PROCEDURE FOR EXERCISE.
     ----------------------

          (a)  Payment.
               -------

          At the time an option is granted, the Committee shall, in its
discretion, specify one or more of the following forms of payment which may be
used by an Optionee upon exercise of his or her option:

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               (i)   cash or personal or certified check payable to the Company
               in an amount equal to the aggregate Option Price of the shares
               with respect to which the option is being exercised;

               (ii)  stock certificates (in negotiable form) representing shares
               of Common Stock having a fair market value (as determined by the
               Committee, which determination, if the Common Stock is publicly
               traded, shall be based upon market prices) equal to the aggregate
               Option Price of the shares with respect to which the option is
               being exercised; provided, however, that this method of payment
               may only be implemented if the Optionee has owned such shares of
               Common Stock, beneficially and of record, for a period of at
               least six (6) consecutive months immediately prior to exercise of
               his or her Option;

               (iii) cash proceeds equal to the aggregate Option Price of the
               shares with respect to which the option is being exercised
               derived from the simultaneous exercise of the option and sale of
               the underlying shares; or

               (iv)  a combination of any of such methods,

          (b)  Notice.
               ------

          An Optionee (or other person, as provided in Section 13(a) below) may
exercise an option, in whole or in part as provided in the Option Agreement
evidencing such option, by delivering a written notice (the "Notice") to the
Secretary of the Company. The Notice shall:

               (i)   state that the Optionee elects to exercise the option and
               whether the option being exercised is an ISO or an NSO;

               (ii)  state the number of shares with respect to which the option
               is being exercised (the "Optioned Shares");

               (iii) state the method of payment for the Optioned Shares (which
               method must be available to the Optionee under the terms of his
               or her Option Agreement) and, if applicable, that cash, a check
               and stock certificates (as the case may be) are enclosed
               representing all or part of the aggregate Option Price of such
               Optioned Shares;

               (iv)  state the date upon which the Optionee desires to
               consummate the purchase of the Optioned Shares (which date must
               be prior to termination of such option under Section 10 below);

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               (v)   include any representation of the Optionee required
               pursuant to Section 8(b)(iii) above,

               (vi)  in the event the option is exercised pursuant to Section
               13(a) below by any person other than the Optionee, include
               evidence to the satisfaction of the Committee of the right of
               such person to exercise the option; and

               (vii) include such further provisions consistent with the Plan as
               the Committee may from time to time require.

Within 30 days from the exercise date of any option, the Optionee shall deliver
to the Company a copy of any election filed by the Optionee with the Internal
Revenue Service under Section 83(b) of the Code.

          (c)  Issuance of Certificates.
               ------------------------

The Company shall issue a stock certificate in the name of the Optionee (or such
other person exercising the Option in accordance with the provisions of Section
13(a) below) for the Optioned Shares as soon as practicable after receipt of the
notice and payment of the aggregate Option Price for such shares. All such
certificates, if so provided in the Option Agreement of such Optionee, shall
bear a legend in substantially the form set forth in Section 13(b) below, and
all certificates representing shares of Common Stock not registered under the
1933 Act shall bear the legend set forth in Section 8(b)(iii) above. Neither the
Optionee nor any person exercising an option in accordance with the provisions
of Section 13(a) below shall have any privileges as a stockholder of the Company
with respect to any shares of stock subject to an option until such shares shall
be registered on the books of the Company in the name of such person.

10.  TERMINATION OF EMPLOYMENT; DISABILITY AND DEATH.
     -----------------------------------------------

          (a)  General.
               -------

          Subject to the provisions of Section 8(b) above, the Committee may
determine the period or periods of time during which an Optionee may exercise an
option following (i) the termination by the Company, with or without cause, of
the Optionee's employment or other relationship with the Company, (ii) the
termination by the Optionee of any such relationship with the Company, or (iii)
the death or permanent and total disability of the Optionee (within the meaning
of Section 22(e)(3) of the Code). Such period or periods shall be set forth in
the Option Agreement evidencing each such option.

          (b)  Incentive Stock Options
               -----------------------

          No ISO may be exercised unless, at the time of exercise, the Optionee
is, and has continuously since the date of the grant of such ISO been, employed
by the Company, and, subject to the provisions of Section 8(b) above, the right
to exercise the

                                       7
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unexercised portion of any ISO shall forthwith terminate upon the first to occur
of the following:

               (i)   the expiration of not more than three months from the date
               of termination of the Optionee's employment (other than a
               termination described in subparagraph (ii) or (iii) below);
               provided, however that if the Optionee shall die or become
               --------  -------
               permanently and totally disabled (within the meaning of Section
               22(e)(3) of the Code) during such three-month period, the time of
               termination of the unexercised portion of such option shall be
               determined in accordance with subparagraph (ii) below;

               (ii)  the expiration of not more than 12 months from the date of
               termination of the Optionee's employment if such termination is
               due to such Optionee's death or permanent and total disability
               (within the meaning of Section 22(e)(3) of the Code);

               (iii) immediately upon the termination by the Company of the
               Optionee's employment if such termination is for cause, as
               determined by the Committee, or is otherwise attributable to a
               breach, as determined by the Committee, by the Optionee of an
               employment agreement with the Company; or

               (iv)  the expiration of such period of time or the occurrence of
               such event as the Committee in its discretion may provide in the
               Option Agreement evidencing such option.

11.  ANTIDILUTION.
     ------------

          In the event the Common Stock is changed by reason of a stock split,
reverse stock split, stock dividend or recapitalization (exclusive of any future
public or private sales of Common Stock), or is converted into or exchanged for
other securities as a result of a merger, consolidation or reorganization in
which the Company is the surviving corporation, appropriate adjustments shall be
made, as determined by the Committee, in the terms of the outstanding options,
or additional options may be granted under the Plan as shall be equitable and
appropriate, in order to make such outstanding options, as nearly as may be
practicable, equivalent to such options immediately prior to such change. A
corresponding adjustment changing the number and class of shares allocated to,
and the Option Price of, each option or portion thereof outstanding at the time
shall likewise be made. In the case of ISOS, no such adjustment shall be made
which would constitute a modification, extension or renewal of such ISOs within
the meaning of Section 424 of the Code.

                                       8
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12.  CORPORATE TRANSACTIONS.
     ----------------------

          In the event the Common Stock is exchanged for securities, cash or
other property of any other corporation or entity as the result of a
reorganization, merger or consolidation in which the Company is not the
surviving corporation, the dissolution or liquidation of the Company, or the
sale of all or substantially all the assets of the Company, the Committee or
the, Board of Directors of the Company may, in its discretion, as to outstanding
options (a) accelerate the exercise date or dates of such options pursuant to
Section 8(a) above, (b) upon written notice to the holders thereof, provided the
options have been accelerated pursuant to clause (a) above, terminate all such
options prior to the consummation of the transaction unless exercised within a
prescribed period, (c) provide for payment of an amount equal to the excess of
the fair market value, as determined by the Committee or such board, over the
Option Price of such shares as of the date of the transaction, in exchange for
the surrender of the right to exercise such options, or (d) provide for the
assumption of such options, or the substitution therefor of new options, by the
successor corporation or entity; provided, however, that with respect to ISOs
                                 --------  -------
the requirements of Section 424 of the Code shall be met.

13.  RESTRICTIONS ON OPTIONS AND OPTIONED SHARES.
     -------------------------------------------

          (a)  Nonassignability of Option Rights.
               ---------------------------------

          No option granted under this Plan shall be assignable or otherwise
transferable by the Optionee otherwise than by will or the laws of descent and
distribution, and shall be exercisable during the lifetime of the Optionee only
by him or her. In the event of the death of an Optionee, any option held by such
Optionee may thereafter be exercised by his or her representatives, executors or
administrators to the full extent to which such option was exercisable by the
Optionee at the time of his or her death.

          (b)  Right of First Refusal; Right of First Offer.
               --------------------------------------------

          The Committee, in its discretion, may provide in any Option Agreement
that the Company or its designee shall have a right of first refusal or right of
first offer on the sale or transfer of any shares of Common Stock issued upon
exercise of the option subject to such Option Agreement, in the manner provided
therein, such right of first refusal or right of first offer to expire upon the
consummation of the initial Public offering of the Common Stock pursuant to the
1933 Act. Any certificate representing shares of Common Stock issued pursuant to
an Option Agreement containing a right of first refusal or right of first offer
shall bear a legend in substantially the following form:

"THE TRANSFER OF THESE SECURITIES IS SUBJECT TO THE TERMS AND CONDITIONS OF A
STOCK OPTION AGREEMENT DATED AS OF ______________ AMONG ESPIRION THERAPEUTICS,
INC., AND THE HOLDER OF RECORD OF THIS CERTIFICATE, AND NO SALE, ASSIGNMENT,

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TRANSFER, PLEDGE, HYPOTHECATION OR OTHER DISPOSITION OF SUCH SECURITIES SHALL BE
VALID OR EFFECTIVE EXCEPT IN ACCORDANCE WITH SUCH AGREEMENT AND UNTIL SUCH TERMS
AND CONDITIONS HAVE BEEN FULFILLED. COPIES OF SUCH AGREEMENT MAY BE OBTAINED AT
NO COST BY WRITTEN REQUEST MADE BY THE HOLDER OF RECORD OF THIS CERTIFICATE TO
THE SECRETARY OF ESPERION THERAPEUTICS, INC."

14.  EFFECTIVE DATE.
     --------------

          The Plan shall become effective on the date (the "Effective Date") of
its adoption by the Board; provided, however, that no option intended to be an
                           --------  -------
ISO shall be exercisable by an Optionee unless and until the Plan shall have
been approved by the stockholders, of the Company with before or after the date
of adoption of the Plan by the Board.

15.  EXPIRATION AND TERMINATION.
     --------------------------

          Except with respect to options then outstanding, the Plan shall expire
on the earliest to occur of (a) the tenth anniversary of the date on which the
Plan was adopted by the Board, (b) the tenth anniversary of the date on which
the Plan is approved by the stockholders of the Company, or (c) the date as of
which the Board, in its sole discretion, determines to terminate the Plan (the
"Date"). Any options outstanding as of the Expiration Date shall remain in
effect until they have been exercised or have terminated or expired by their
respective terms.

16.  AMENDMENT.
     ---------

          The Board may at any time terminate, modify or amend the Plan;
provided, however, that if the approval of the stockholders of the Company shall
--------  -------
be required for any modification or amendment under Section 422 of the Code,
with respect to ISOS, or under Rule 16b-3 under the Securities Exchange Act of
1934, as amended with respect to shares of Common Stock registered under such
Act, such approval shall be obtained before such modification or amendment shall
become effective. No termination, modification or amendment of the Plan may,
without the consent of an Optionee adversely affect his or her rights under an
option previously granted to such Optionee.

17.  DISQUALIFYING DISPOSITIONS.
     --------------------------

          If stock acquired upon exercise of an ISO granted under the Plan is
disposed of by the Optionee within two years from the date of grant of the ISO
or within one year after the transfer of the Optioned Shares to such Optionee (a
"disqualifying disposition"), such Optionee shall, immediately prior to such
 -------------------------
disqualifying disposition, notify the Company in writing of the date and terms
of such disposition and provide such other information regarding the disposition
as the Company may reasonably require.

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18.  TAXES.
     -----

The Company may deduct from any cash payments due to an Optionee upon exercise
of an option any federal, state or local withholding taxes and employment taxes
relating thereto or, as a condition of delivery of any Optioned Shares due upon
such exercise, require the Optionee to remit, or, in appropriate cases, agree to
remit when due, an amount sufficient to satisfy such taxes; provided, however,
                                                            --------  -------
that, subject to the prior approval of the Committee, the Optionee may, in whole
or in part, satisfy such obligations (a) by permitting the Company to withhold
some or all of such Optioned Shares, or (b) by delivering shares of Common Stock
already owned by him or her. Shares so withheld or delivered shall have a fair
market value, as determined by the Committee, equal to such obligations as of
the date or dates the amounts of such taxes are required to be determined. At
the time of any disqualifying disposition, the Optionee shall remit to the
Company in cash the amount of any such taxes relating to such disposition.

19.  CAPTIONS.
     --------

          The use of captions in the Plan or any Option Agreement is for the
convenience of reference only and shall not affect the meaning of any provision
of the Plan or such Option Agreement.

20.  GOVERNING LAW.
     -------------

The validity and construction of the Plan and the Option Agreements shall be
construed in accordance with and governed by the law of the State of Delaware.

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