Exhibit 3.1 

AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION

OF

FLEXION THERAPEUTICS, INC.

1.            Name. The name of the corporation is Flexion Therapeutics, Inc. (the “Corporation”).

2.            Registered Office. The registered office of the Corporation in the State of Delaware is located at 1209 Orange Street in the City of Wilmington 19801, County of New Castle. The name of its registered agent at such address is The Corporation Trust Company.

3.            Purpose. The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware.

4.            Stock. The total number of shares of stock the Corporation shall have authority to issue is one thousand (1,000) shares of Common Stock, $0.001 par value per share. Each share of Common Stock shall be entitled to one vote.

5.            Change in Number of Shares Authorized. Except as otherwise provided in the provisions establishing a class of stock, the number of authorized shares of any class or series of stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the voting power of the Corporation entitled to vote irrespective of the provisions of Section 242(b)(2) of the General Corporation Law of the State of Delaware.

6.            Election of Directors. The election of directors need not be by written ballot unless the bylaws shall so require.

7.            Authority of Directors. In furtherance of and not in limitation of the power conferred upon the board of directors by law, the board of directors shall have the power to make, adopt, alter, amend and repeal from time to time bylaws of the Corporation, subject to the right of the stockholders entitled to vote with respect thereto to alter and repeal bylaws made by the board of directors.

8.            Liability of Directors. A director of the Corporation shall not be liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except to the extent that exculpation from liability is not permitted under the General Corporation Law of the State of Delaware as in effect at the time such liability is determined. No amendment or repeal of this paragraph 8 shall apply to or have any effect on the liability or alleged liability of any director of the Corporation for or with respect to any acts or omissions of such director occurring prior to such amendment or repeal.

9.            Indemnification. The Corporation shall, to the maximum extent permitted from time to time under the law of the State of Delaware, indemnify and upon request advance expenses to any person who is or was a party or is threatened to be made a party to any threatened, pending or completed action, suit, proceeding or claim, whether civil, criminal, administrative or investigative, by reason of the fact that such person is or was or has agreed to be a director or officer of the Corporation or while a director or officer is or was serving at the request of the Corporation as a director, officer, partner, trustee, employee or agent of any corporation, partnership, joint venture, trust or other enterprise, including service with respect to employee benefit plans, against expenses (including attorney’s fees and expenses), judgments, fines, penalties and amounts paid in settlement incurred (and not otherwise recovered) in connection with the investigation, preparation to defend or defense of such action, suit, proceeding or claim; provided, however, that the foregoing shall not require the Corporation to indemnify or advance expenses to any person in connection with any action, suit, proceeding, claim or counterclaim initiated by or on behalf of such person. Such indemnification shall not be exclusive of other indemnification rights arising under any by-law, agreement, vote of directors or stockholders or otherwise and shall inure to the benefit of the heirs and legal representatives of such person. If applicable law is amended after approval by the stockholders of this Article 9 to authorize corporate action further eliminating or limiting the personal liability of directors or officers, then the liability of a director to the Corporation shall be eliminated or limited to the fullest extent permitted by applicable law as so amended. Any repeal or modification of the foregoing provisions of this paragraph 9 shall only be prospective and shall not adversely affect any right or protection of a director or officer of the Corporation with respect to any acts or omissions of such director or officer of the Corporation occurring prior to such repeal or modification.

10.            Records. The books of the Corporation may (subject to any statutory requirements) be kept outside the State of Delaware as may be designated by the board of directors or in the bylaws of the Corporation.