RESTRICTED STOCK PURCHASE AGREEMENT

Exhibit 10.10

RESTRICTED STOCK PURCHASE AGREEMENT

THIS RESTRICTED STOCK PURCHASE AGREEMENT (this “ Agreement ”) is entered into as of the 29 ^th day of April, 2005, by and between Aegerion Pharmaceuticals, Inc., a Delaware corporation (the “ Corporation ”), and William H. Lewis (the “ Equity Participant ”).

W I T N E S S E T H:

WHEREAS, the Corporation desires to issue to the Equity Participant, and the Equity Participant desires to purchase from the Corporation, shares of the Corporation’s Common Stock, $0.001 par value per share (the “ Common Stock ”).

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties do hereby agree as follows:

SECTION 1. Definitions .

As used in this Agreement, the following terms shall have the following respective meanings:

“ Bridge Financing ” shall have the meaning set forth in the Term Sheet.

“ Cause ” shall have the meaning set forth in the Consulting Agreement or Employment Agreement, as applicable.

“ Code ” shall mean the Internal Revenue Code of 1986, as amended, and the regulations promulgated thereunder.

“ Commission ” shall mean the Securities and Exchange Commission or any other Federal agency administering the Securities Act at the applicable time.

“ Consideration ” shall have the meaning set forth in Section 2.1 .

“ Consulting Agreement ” shall mean the Consulting Agreement proposed to be entered into by and between the Corporation and the Equity Participant.

“ Employment Agreement ” shall mean the Employment Agreement proposed to be entered into by and between the Corporation and the Equity Participant pursuant to which the Equity Participant will be employed as the full-time Chief Financial Officer of the Corporation.

“ Equity Stock ” shall have the meaning set forth in Rule 3a11-1 under the Securities Exchange Act of 1934, as amended, and any successor statute and the rules and regulations thereunder, as shall be in effect from time to time.

“ Executive Commencement Date ” shall have the meaning set forth in the Term Sheet.

“ Fair Market Value ” shall mean the fair market value, with respect to any Share, as determined by the Board of Directors of the Corporation.

“ Family ” shall mean any spouse, lineal ancestor or descendant, or sibling or any trust for the exclusive benefit of any of the foregoing and/or the Equity Participant.

“ Group ” shall mean as to (a) a partnership, any or all of its general or limited partners or any “affiliate” thereof (as defined by Rule 405 promulgated under the Securities Act), (b) a trust, any of the beneficiaries, settlers or grantors now existing or hereafter arising of, or any Person under common control with, such trust, (c) a corporation, any of its stockholders, any subsidiary of such corporation or any corporation which is under common control with such corporation, or any directors, officers or employees of such corporation, and (d) a limited liability company, any of its members.

“ Initial Public Offering ” shall mean the Corporation’s initial distribution of New Securities in an underwritten Public Offering to the general public pursuant to a registration statement filed with and declared effective by the Commission pursuant to the Securities Act at a price per New Security of not less than the product of three (3) and the original purchase price per share for the Corporation’s initial round of Series A Preferred Stock (as adjusted for stock splits, stock dividends or similar recapitalizations) and resulting in net proceeds to the Corporation of not less than $40 million.

“ IRS ” shall mean the Internal Revenue Service.

“ New Securities ” shall mean any Equity Stock, including, but not limited to, shares of Common Stock, any security which is convertible into or exercisable or exchangeable for Common Stock, or any right, option or warrant to acquire any Common Stock.

“ Original Cost Per Share ” shall have the meaning set forth in Section 2.1 .

“ Person ” shall mean and include a natural person, a corporation, a partnership, a limited liability company, a trust, an unincorporated organization, an educational institution, a government or any department, agency or political subdivision thereof, or any other entity.

“ Preferred Shares ” shall mean, at the applicable time, all issued and outstanding shares, if any, of the Corporation’s preferred stock.

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“ Public Offering ” shall mean a distribution of New Securities in a firm commitment underwritten public offering to the general public pursuant to a registration statement filed with and declared effective by the Commission pursuant to the Securities Act.

“ Released Shares ” shall mean Shares that, in accordance with Sections 3.1 and 3.2 are no longer subject to repurchase by the Corporation pursuant to Section 4 .

“ Securities Act ” shall mean the Securities Act of 1933, as amended, and any successor statute and the rules and regulations of the Commission thereunder, as shall be in effect at the applicable time.

“ Shares ” shall have the meaning set forth in Section 2.1 .

“ Term Sheet ” shall mean the term sheet, dated as of April 25 ^th , 2005, by and between the Corporation and the Equity Participant.

“ Transfer ” shall include any direct or indirect sale, assignment, transfer, pledge (but not including a pledge in favor of the Corporation), hypothecation or other disposition of any Shares or of any legal or beneficial interest therein.

“ Unreleased Shares ” means Shares that are not Released Shares.

SECTION 2. Issuance of Common Stock .

2.1 Subject to the terms and conditions contained herein, the Corporation hereby sells to the Equity Participant, and the Equity Participant hereby purchases from the Corporation, 700,000 shares of Common Stock (the “ Shares ”) for a purchase price of $.001 per share (the “ Original Cost Per Share ”) or the aggregate purchase price of $700.00 (the “Consideration”). Simultaneously with execution and delivery hereof, the Equity Participant is delivering to the Corporation a check or wire transfer of funds in the aggregate amount of the Consideration.

2.2 The Equity Participant, in his sole discretion, may make an effective election with the IRS under Section 83(b) of the Code and the regulations promulgated thereunder in the form of Exhibit A attached hereto. The Equity Participant understands that under applicable law such election must be filed with the IRS no later than thirty (30) days after any acquisition of the Shares to be effective. If the Equity Participant files an effective election, the excess of the fair value of the Shares (which the IRS may assert is different from the fair value determined by the Equity Participant) covered by such election over the amount paid by the Equity Participant for the Shares shall be treated as ordinary income received by the Equity Participant. If the Equity Participant does not file an effective election, future appreciation on the Shares will generally be taxable as ordinary income when the right of repurchase lapses as to such Shares pursuant to this Agreement. The foregoing is merely a brief summary of complex tax regulations, and therefore, the Equity Participant is strongly advised to consult with his own tax advisors.

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2.3 In the event that the Equity Participant files the election referred to in Section 2.2 above, the Equity Participant will provide the Corporation with a copy of such election as filed.

SECTION 3. Repurchase Rights related to Common Stock .

3.1 From the date of execution of this Agreement until the execution of the Employment Agreement, the Shares shall be released in a series of successive equal daily installments of 479 shares.

3.2 Upon the execution of the Employment Agreement by the Equity Participant and the Corporation, the Shares which remain unreleased after the release of those Shares pursuant to Section 3.1 shall be released in accordance with the following table:

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3.3 In the event that the Equity Participant does not execute the Employment Agreement prior to or in connection with the closing of the Bridge Financing or the Consulting Agreement with the Equity Participant is terminated by the Corporation for any reason (with or without Cause) other than the commencement of his full time employment with the Corporation pursuant to the Employment Agreement, the Shares which remain unreleased at such time, after the release of those Shares pursuant to Section 3.1 , shall cease being released on the earlier of the date of the closing of such Bridge Financing or the date of termination of the consulting arrangement, as applicable, and remain Unreleased Shares.

3.4 Notwithstanding the foregoing, in the event the Equity Participant’s employment is terminated without Cause in relation to the sale or other disposition of all or substantially all of the Corporation’s assets or a change in ownership in a single transaction or series of related transactions of fifty percent (50%) or more of the Corporation’s stock, the Shares which remain unreleased at the time of termination, after the release of those Shares pursuant to Section 3.2 , shall-be released on the date of such termination and become Released Shares; provided, however that this provision shall not apply in the event of any equity financings of the Corporation.

3.5 Except as provided for in Section 3.4 , above, in the event the Equity Participant’s employment is terminated without Cause, twenty-five percent (25%) of the Unreleased Shares on the date of such termination shall be released on the date of such termination and become Released Shares.

SECTION 4. Termination of Relationship .

4.1    (a) In the event that the Equity Participant’s consulting is terminated for Cause prior to the execution of the Employment Agreement, the Corporation shall have the right to purchase from the Equity Participant, and if the Corporation exercises its option pursuant to this Section 4 , the Equity Participant shall sell to the Corporation upon the exercise of such right, all of the Equity Participant’s Unreleased Shares (rounded up to the nearest whole Share) at the Original Cost Per Share.

(b) In the event that the Equity Participant executes the Employment Agreement prior to or in connection with the closing of the Bridge Financing, and his employment is subsequently terminated for any reason (with or without Cause), the Corporation shall have the right to purchase from the Equity Participant, and if the Corporation exercises its option pursuant to this Section 4 , the Equity Participant shall sell to the Corporation upon the exercise of such right, (1) all of the Equity Participant’s Unreleased Shares (rounded up to the nearest whole Share) at the Original Cost Per Share, and (2) all of the Equity Participant’s Released Shares (rounded up to the nearest whole Share) at the Fair Market Value per Share; provided, however, that if, after the Executive Commencement Date, the Equity Participant’s employment is terminated by the Corporation for Cause pursuant to the terms and conditions of the Employment Agreement, the purchase price for any Released Shares shall be the Original Cost Per Share.

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(c) For purposes of clause (b) above, Released Shares shall not include those shares that were released during the consulting period.

4.2 The number of Shares subject to purchase pursuant to Section 4.1 shall be adjusted to give effect to any stock dividend, or other distribution of stock made on or in respect of such Shares, or any subdivision, combination or reclassification of the outstanding capital stock of the Corporation or received in exchange for the Shares.

4.3 In order to exercise the option to purchase the Equity Participant’s Shares under this Section 4 , the Corporation shall deliver a written notice to the Equity Participant (the “ Share Repurchase Notice ”), indicating its election to purchase any or all of the Shares and specifying the number of Unreleased Shares and Released Shares, if applicable, which the Corporation elects to purchase and the purchase price therefor, within ninety (90) days after the Equity Participant’s termination.

4.4 The repurchase of Shares hereunder shall be made on a date within sixty (60) days of the delivery of the Share Repurchase Notice, by delivery of payment to the Equity Participant, by check or wire transfer, against receipt of one or more certificates, properly endorsed, evidencing the Equity Participant’s Unreleased and/or Released Shares, if applicable, to be so purchased. If the repurchase is not consummated by such date, the Corporation may deliver to the Equity Participant by check or wire transfer the applicable repurchase price for the Unreleased Shares and/or Released Shares, if applicable, to be repurchased and may cancel the certificates evidencing such Unreleased Shares and/or Released Shares, if applicable, on the books and records of the Corporation.

4.5 Notwithstanding anything to the contrary contained in this Agreement, all repurchases of Shares by the Corporation shall be subject to applicable restrictions contained in federal law; the Delaware General Corporation Law and in the Corporation’s debt and equity financing agreements. Notwithstanding anything to the contrary contained in this Agreement, if any such restrictions prohibit or otherwise delay the repurchase of any Shares thereunder which the Corporation is otherwise entitled to make, the Corporation may make such repurchases within sixty (60) days of the date that it is permitted to do so under such restrictions.

4.6 In the event that any Shares are the subject of repurchase by the Corporation pursuant to this Section 4 , the Equity Participant and his successors, assigns or representatives will take all steps necessary and desirable to obtain all required third-party, governmental and regulatory consents and approvals and take all other actions necessary and desirable to facilitate consummation of such repurchase(s) in a timely manner as are requested by the Corporation.

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SECTION 5. Legend on Shares and Notice of Transfer .

5.1 Restrictive Legends .

(a) Each certificate evidencing Shares, and each certificate evidencing Shares held by subsequent transferees of any such certificate, shall (unless otherwise permitted by the provisions of Section 5.2 hereof) be stamped or otherwise imprinted with a legend in substantially the following form:

THE 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.

(b) Each certificate evidencing Shares, and each certificate evidencing Shares held by subsequent transferees of any such certificate, shall also be stamped or otherwise imprinted with a legend in substantially the following form:

ADDITIONALLY, THE TRANSFER OF THESE SECURITIES IS SUBJECT TO THE TERMS AND CONDITIONS OF A RESTRICTED STOCK PURCHASE AGREEMENT EFFECTIVE AS OF APRIL 29, 2005, BETWEEN AEGERION PHARMACEUTICALS, INC. AND THE HOLDER OF RECORD OF THIS CERTIFICATE AND NO SALE, ASSIGNMENT, 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 AEGERION PHARMACEUTICALS, INC.

5.2 Notice of Transfer .

(a) The Equity Participant, and any other holder of any Shares by acceptance thereof, agrees that, prior to any Transfer of any Shares, such holder will give written notice to

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the Corporation of such holder’s intention to effect such Transfer and to comply in all other respects with the provisions of this Section 5.2 . Each such notice shall contain (i) a statement setting forth the intention of said holder’s prospective transferee with respect to its retention or disposition of said Shares; and (ii) unless waived by the Corporation, an opinion of counsel for said holder as to the necessity or non-necessity for registration under the Securities Act and applicable state securities laws in connection with such Transfer and stating the factual and statutory basis relied upon by counsel. The following provisions shall then apply:

(i) If the proposed Transfer of Shares may be effected without registration or qualification under the Securities Act and any applicable state securities laws, then the registered holder of such Shares shall be entitled to Transfer such Shares in accordance with Section 5 hereof and the intended method of disposition specified in the statement delivered by said holder to the Corporation.

(ii) If the proposed Transfer of such Shares may not be effected without registration under the Securities Act or registration or qualification under any applicable state securities laws, the registered holder of such Shares shall not be entitled to Transfer such Shares pursuant to Section 6 until the requisite registration or qualification is effective.

(b) Notwithstanding the provisions of Section 5.2(a) , in the case of a Transfer by a holder to a member of such holder’s Family or Group, no such opinion of counsel shall be necessary; provided, that the transferee agrees in writing to be subject to Section 5 hereof t