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                                                                     EXHIBIT 3.1


                           SIXTH AMENDED AND RESTATED
                          CERTIFICATE OF INCORPORATION

                                       OF

                         NORTHWEST BIOTHERAPEUTICS INC.


      The undersigned, Daniel O. Wilds and Alton L. Boynton, hereby certify
that:

      1. They are the duly elected and acting President and Secretary,
respectively, of Northwest Biotherapeutics, Inc., a Delaware corporation.

      2. The Certificate of Incorporation of this corporation was originally
filed with the Secretary of State of Delaware on July 29, 1998.

      3. The First Amended and Restated Certificate of Incorporation of this
corporation was filed with the Secretary of State of Delaware on September 15,
1998.

      4. The Second Amended and Restated Certificate of Incorporation of this
corporation was filed with the Secretary of State of Delaware on March 26, 1999.

      5. The Third Amended and Restated Certificate of Incorporation of this
corporation was filed with the Secretary of State of Delaware on October 24,
2000.

      6. The Fourth Amended and Restated Certificate of Incorporation of this
corporation was filed with the Secretary of State of Delaware on June 1, 2001.

      7. The Fifth Amended and Restated Certificate of Incorporation of this
corporation was filed with the Secretary of State of Delaware on June 26, 2001.

      8. The Certificate of Incorporation of this corporation shall be amended
and restated to read in full as follows:

                                    ARTICLE I

      The name of the corporation is Northwest Biotherapeutics Inc. (the
"Corporation").

                                   ARTICLE II

      The address of the Corporation's registered office in the State of
Delaware is 2711 Centerville Road, Suite 400, Wilmington, Delaware 19808, County
of New Castle. The name of its registered agent at such address is Corporation
Service Company.


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                                   ARTICLE III

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

                                   ARTICLE IV

                                 CAPITALIZATION

      1. Authorized Capital.

            (a) The total number of shares of stock that the Corporation shall
have the authority to issue is one hundred forty million (140,000,000) shares of
capital stock, consisting of (i) fifteen million (15,000,000) shares of
preferred stock, par value $0.001 per share (the "Preferred Stock"), and (ii)
one hundred twenty-five million (125,000,000) shares of common stock, par value
$0.001 per share (the "Common Stock").

            (b) Subject to the provisions of this Certificate of Incorporation
and the Preferred Stock Designation (as defined below) creating any series of
Preferred Stock, the Corporation may issue shares of its capital stock from time
to time for such consideration (not less than the par value thereof) as may be
fixed by the Board of Directors of the Corporation (the "Board of Directors"),
which is expressly authorized to fix the same in its absolute discretion subject
to the foregoing conditions. Shares so issued for which the consideration shall
have been paid or delivered to the Corporation shall be deemed fully paid stock
and shall not be liable to any further call or assessment thereon, and the
holders of such shares shall not be liable for any further payments in respect
of such shares.

            (c) The right to cumulate votes for the election of directors as
provided in Section 214 of the DGCL shall not be granted and is hereby expressly
denied.

            (d) No stockholder of the Corporation shall by reason of his/her/its
holding shares of any class of capital stock of the Corporation have any
preemptive or preferential right to acquire or subscribe for any additional,
unissued or treasury shares (whether now or hereafter acquired) of any class of
capital stock of the Corporation now or hereafter to be authorized, or any
notes, debentures, bonds or other securities convertible into or carrying any
right, option or warrant to subscribe for or acquire shares of any class of
capital stock of the Corporation now or hereafter to be authorized, whether or
not the issuance of any such shares or such notes, debentures, bonds or other
securities would adversely affect the dividends or voting or other rights of
that stockholder.

2.  Preferred Stock.

            (a) The Preferred Stock may be issued from brae to time in one or
more series. Authority is hereby expressly granted to and vested in the Board of
Directors to authorize from time to time the issuance of Preferred Stock in one
or more series. With respect to each


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series of Preferred Stock authorized by it, the Board of Directors shall be
authorized to establish by resolution or resolutions, and by filing a
certificate pursuant to applicable law of the State of Delaware (the "Preferred
Stock Designation"), the following to the fullest extent now or hereafter
permitted by the DGCL:

                  (1) the designation of such series;

                  (2) the number of shares to constitute such series;

                  (3) whether such series is to have voting rights (full,
      special or limited) or is to be without voting rights;

                  (4) if such series is to have voting rights, whether or not
      such series is to be entitled to vote as a separate class either alone or
      together with the holders of the Common Stock or one or more other series
      of Preferred Stock;

                  (5) the preferences and relative, participating, optional,
      conversion or other special rights (if any) of such series and the
      qualifications, limitations or restrictions (if any) with respect to such
      series;

                  (6) the redemption rights and price(s), if any, of such
      series, and whether or not the shares of such series shall be subject to
      the operation of retirement or sinking funds to be applied to the purchase
      or redemption of such shares for retirement and, if such retirement or
      sinking funds or funds are to be established, the periodic amount thereof
      and the terms and provisions relative to the operation thereof,

                  (7) the dividend rights and preferences (if any) of such
      series, including, without limitation, (i) the rates of dividends payable
      thereon, (ii) the conditions upon which and the time when such dividends
      are payable, (iii) whether or not such dividends shall be cumulative or
      noncumulative and, if cumulative, the date or dates from which such
      dividends shall accumulate and (iv) whether or not the payment of such
      dividends shall be preferred to the payment of dividends payable on the
      Common Stock or any other series of Preferred Stock;

                  (8) the preferences (if any), and the amounts thereof, which
      the holders of such series shall be entitled to receive upon the voluntary
      or involuntary liquidation, dissolution or winding-up of, or upon any
      distribution of the assets of, the Corporation;

                  (9) whether or not the shares of such series, at the option of
      the Corporation or the holders thereof or upon the happening of any
      specified event, shall be convertible into or exchangeable for (i) shares
      of Common Stock, (ii) shares of any other series of Preferred Stock or
      (iii) any other stock or securities of the Corporation;

                  (10) if such series is to be convertible or exchangeable, the
      price or prices or ratio or ratios or rate or rates at which such
      conversion or exchange may be


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      made and the terms and conditions (if any) upon which such price or prices
      or ratio or ratios or rate or rates may be adjusted; and

                  (11) such other rights, powers and preferences with respect to
      such series as may to the Board of Directors seem advisable.

      Any series of Preferred Stock may vary from any other series of Preferred
Stock in any or all of the foregoing respects and in any other manner.

            (b) The Board of Directors may, with respect to any existing series
of Preferred Stock but subject to the Preferred Stock Designation creating such
series, (i) increase the number of shares of Preferred Stock designated for such
series by a resolution adding to such series authorized and unissued shares of
Preferred Stock not designated for any other series and (ii) decrease the number
of shares of Preferred Stock designated for such series by a resolution
subtracting from such series shares of Preferred Stock designated for such
series (but not below the number of shares of such series then outstanding), and
the shares so subtracted shall become authorized, unissued and undesignated
shares of Preferred Stock.

            (c) No vote of the holders of the Common Stock or the Preferred
Stock shall, unless otherwise expressly provided in a Preferred Stock
Designation creating any series of Preferred Stock, be a prerequisite to the
issuance of any shares of any series of the Preferred Stock authorized by and
complying with the conditions of this Certificate of Incorporation. Shares of
any series of Preferred Stock that have been authorized for issuance pursuant to
this Certificate of Incorporation and that have been issued and reacquired in
any manner by the Corporation (including upon conversion or exchange thereof)
shall be restored to the status of authorized and unissued shares of Preferred
Stock and may be reissued as part of a new series of Preferred Stock to be
created by resolution or resolutions of the Board of Directors and a Preferred
Stock Designation as set forth above.

      3. Common Stock.

            (a) The holders of shares of the Common Stock shall be entitled to
vote upon all matters submitted to a vote of the common stockholders of the
Corporation and shall be entitled to one vote for each share of the Common Stock
held.

            (b) Subject to the prior rights and preferences (if any) applicable
to shares of Preferred Stock of any series, the holders of shares of the Common
Stock shall be entitled to receive such dividends (payable in cash, stock or
otherwise) as may be declared thereon by the Board of Directors at any time and
from time to time out of any funds of the Corporation legally available
therefor.

            (c) In the event of any voluntary or involuntary liquidation,
dissolution or winding-up of the Corporation, after payment or provision for
payment of the debts and other liabilities of the Corporation and subject to the
preferential or other rights (if any) of the holders of shares of the Preferred
Stock in respect thereof, the holders of shares of the Common Stock shall be
entitled to receive all the remaining assets of the Corporation available for
distribution to


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its stockholders, ratably in proportion to the number of shares of the Common
Stock held by them. For purposes of this paragraph (c), a liquidation,
dissolution or winding-up of the Corporation shall not be deemed to be
occasioned by or to include (i) any consolidation or merger of the Corporation
with or into another corporation or other entity or (ii) a sale, lease, exchange
or conveyance of all or a part of the assets of the Corporation.

      4. Stock Options, Warrants, etc. Unless otherwise expressly prohibited in
the Preferred Stock Designation creating any series of Preferred Stock, the
Corporation shall have authority to create and issue warrants, rights and
options entitling the holders thereof to purchase from the Corporation shares of
the Corporation's capital stock of any class or series or other securities of
the Corporation for such consideration and to such persons, firms or
corporations as the Board of Directors, in its sole discretion, may determine,
setting aside from the authorized but unissued capital stock of the Corporation
the requisite number of shares for issuance upon the exercise of such warrants,
rights or options. Such warrants, rights and options shall be evidenced by one
or more instruments approved by the Board of Directors. The Board of Directors
shall be empowered to set the exercise price, duration, time for exercise and
other terms of such warrants, rights or options; provided, however, that the
consideration to be received for any shares of capital stock subject thereto
shall not be less than the par value thereof.

                                    ARTICLE V

      The Board of Directors of the Corporation is expressly authorized to
adopt, amend or repeal Bylaws or adopt new Bylaws; provided however, that the
Board of Directors may not repeal or amend any bylaw that stockholders have
expressly provided may not be amended or repealed by the Board of Directors. The
stockholders shall also have the power to adopt, amend or repeal the Bylaws of
this Corporation by the affirmative vote of the holders of not less than
two-thirds of the outstanding shares entitled to vote thereon and, to the
extent, if any, provided by resolution adopted by the Board of Directors
authorizing the issuance of a class of series of Common Stock or Preferred
Stock, by the affirmative vote of the holders of not less than two-thirds of the
outstanding shares of such class or series, voting as a separate group.

                                   ARTICLE VI

      (A) Board Of Directors. The business and affairs of the Corporation shall
be managed under the direction of a Board of Directors, the number of which
shall be fixed from time to time exclusively by the Board of Directors pursuant
to a resolution adopted by a majority of the total number of authorized
directors (whether or not there exist any vacancies in previously authorized
directorships at the time any such resolution is presented to the Board for
adoption) (the "Whole Board"). The Directors shall be classified with respect to
the time for which they shall severally hold office by dividing them into three
classes, Class I, Class II and Class III, each consisting as nearly as possible
of one-third of the Whole Board. All Directors shall hold office until their
successors are elected and qualified, or until their earlier death, resignation,
disqualification or removal. Class I Directors shall be elected for a term of
one year; Class II Directors shall be elected for a term of two years; and Class
III Directors shall be elected for a term of three years; and at each annual
stockholders' meeting thereafter, successors to the Directors whose terms


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shall expire that year shall be elected to hold office for a term of three
years, so that the term of office of one class of Directors shall expire in each
year. Any vacancy on the Board of Directors that results from an increase in the
number of Directors may be filled by the affirmative vote of a majority of the
Directors then in office and a majority of the Continuing Directors, voting
separately and as a subclass of Directors, and any other vacancy on the Board of
Directors may be filled by the affirmative vote of a majority of the Directors
then in office, although less than a quorum, or by a sole remaining Director.
Any Director elected to fill a vacancy not resulting from an increase in the
number of Directors shall serve for a term equivalent to the remaining unserved
portion of the term of such newly elected Director's predecessor.
Notwithstanding the foregoing, whenever the holders of any one or more classes
or series of preferred stock issued by the Corporation shall have the right,
voting separately by class or series, to elect Directors at an annual or special
meeting of stockholders, the election, term of office, filling of vacancies and
other features of such Directorships shall be governed by the terms of this
Amended and Restated Certificate of Incorporation applicable thereto, and such
Directors shall not be divided into classes pursuant to this Section (A) unless
expressly provided by such terms.

      (B) Removal of Directors by Stockholders. A Director may be removed from
office only for "cause" at a special meeting of stockholders called for that
purpose, by the affirmative vote of the holders of not less than two-thirds of
the shares entitled to elect the Director or Directors whose removal is being
sought. The vacancy created by the removal of any Director under this Section
(B) shall be filled only by the affirmative vote of the holders of at least
two-thirds of the shares entitled to elect the Director who was removed. As used
herein, "cause" shall mean (a) willful and continued material failure, refusal
or inability to perform the Director's duties to the corporation or the willful
engaging in gross misconduct that is materially and demonstrably damaging to the
corporation; or (b) conviction for any crime involving moral turpitude or any
other illegal act that materially and adversely reflects upon the business,
affairs or reputation of the corporation or on the Director's ability to perform
the Director's duties to the corporation.

                                   ARTICLE VII

      (A) To the fullest extent permitted by the Delaware General Corporation
Law, as the same exists or as may hereafter be amended, a director of the
Corporation shall not be personally liable to the Corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director.

      (B) The Corporation shall indemnify to the fullest extent permitted by law
any person made or threatened to be made a party to an action or proceeding,
whether criminal, civil, administrative or investigative, by reason of the fact
that he, his testator or intestate is or was a director or officer of the
Corporation or any predecessor of the Corporation, or serves or served at any
other enterprise as a director or officer at the request of the Corporation or
any predecessor to the Corporation.

      (C) Neither any amendment nor repeal of this Article VII, nor the adoption
of any provision of the Corporation's Certificate of Incorporation inconsistent
with this Article VII, shall eliminate or reduce the effect of this Article VII
in respect of any matter occurring, or any


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action or proceeding accruing or arising or that, but for this Article VII,
would accrue or arise, prior to such amendment, repeal or adoption of an
inconsistent provision

                                 ARTICLE VIII

      (A) Amendments to Restated Certificate of Incorporation. The following
Articles and Sections may be amended or repealed only upon the affirmative vote
of the holders of at least two-thirds of the outstanding shares and, to the
extent, if any, provided by resolution adopted by the Board of Directors
authorizing the issuance of a class or series of Common Stock or Preferred
Stock, by the affirmative vote of the holders of at least two-thirds of the
outstanding shares of such class or series, voting as a separate voting group:

      Article V ("Bylaws");

      Article VI ("Directors");

      Article VII ("Limitation of Director Liability");

      Article VIII ("Amendments to Restated Certificate of Incorporation");

      Article IX ("Business Combinations").

                                   ARTICLE IX

      (A) Business Combinations.

            1. Definitions. For the purposes of this Article IX:

                  a. "Business Combination" means (i) a merger, share exchange
or consolidation of this corporation or any of its Subsidiaries with any other
corporation; (ii) the sale, lease, exchange, mortgage, pledge, transfer or other
disposition or encumbrance, whether in one transaction or a series of
transactions, by this corporation or any of its Subsidiaries of all or a
substantial part of this corporation's assets otherwise than in the usual and
regular course of business; or (iii) any agreement, contract or other
arrangement providing for any of the foregoing transactions.

                  b. "Subsidiary" means a domestic or foreign corporation, a
majority of the outstanding voting shares of which are owned, directly or
indirectly, by this corporation.

            2. Information Considered by Board of Directors. In considering a
Business Combination, the Board of Directors may take into account factors in
addition to potential economic benefits to the stockholders, including without
limitation (i) comparison of the proposed consideration to be received by
stockholders in relation to the then current market price of the corporation's
capital stock, the estimated current value of the corporation in a freely
negotiated transaction and the estimated future value of the corporation as an
independent entity,


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and (ii) the impact of such a transaction on the employees, suppliers and
customers of the corporation and its effect on the communities in which the
corporation operates.

      The foregoing Fifth Amended and Restated Certificate of Incorporation has
been duly adopted by the Corporation's Board of Directors and stockholders in
accordance with the applicable provisions of Sections 228, 242 and 245 of the
General Corporation Law of the State of Delaware.

      Executed at Seattle, Washington, on June 21, 2001.


                                                   /s/ Daniel O. Wilds
                                        ----------------------------------------
                                        Daniel O. Wilds, President


                                                  /s/ Alton L. Boynton
                                        ----------------------------------------
                                        Alton L. Boynton, Secretary


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