EXECUTION VERSION

EXHIBIT 10.4

                FOURTH AMENDMENT TO AMENDED AND RESTATED BINDING

                                   TERM SHEET

            This FOURTH AMENDMENT TO AMENDED AND RESTATED BINDING TERM SHEET
(this "AMENDMENT") is made effective as of May 13, 2005 by and between NORTHWEST
BIOTHERAPEUTICS, INC., a Delaware corporation (the "COMPANY"), and TOUCAN
CAPITAL FUND II, L.P., a Delaware limited partnership ("TOUCAN").

                                    RECITALS

            WHEREAS, the Company and Toucan are party to that certain Binding
Convertible Preferred Stock Term Sheet originally dated April 26, 2004 and
amended and restated on October 22, 2004 as further amended on December 27,
2004, January 26, 2005 and April 12, 2005 (the "CONVERTIBLE PREFERRED STOCK TERM
SHEET").

            WHEREAS, concurrently herewith, the Company and its affiliates, if
any, and Toucan and its designees, are entering into Amendment No. 6 (the "SIXTH
AMENDMENT") to that certain Amended and Restated Recapitalization Agreement by
and between the parties thereto; and

            WHEREAS, in connection with the Sixth Amendment, the Company and
Toucan desire to amend the Convertible Preferred Stock Term Sheet as provided
herein.

                                    AGREEMENT

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

            1. The paragraph of the Convertible Preferred Stock Term Sheet
entitled "Warrants:" is hereby amended and restated in its entirety as follows:

           "The Company shall issue $5.85 million in warrant coverage on the
           first $5.85 million Convertible Preferred Stock purchased for cash
           (the "Preferred Stock Warrants"). Preferred Stock Warrants shall not
           be issued upon conversion of notes, exercise of warrants, or other
           conversion or exercise. The number of warrants to be so issued shall
           be determined on the basis of $0.10 per share. If the total of $5.85
           million is invested in Convertible Preferred Stock, the number of
           warrants issued shall be exercisable for 58.5 million shares of
           Convertible Preferred Stock. The exercise price of such Preferred
           Stock Warrants shall be $.04 per share (subject to adjustment for
           stock splits, stock dividends and the like). The exercise period
           shall commence upon issuance of the Preferred Stock Warrants, and
           shall continue for a period of seven (7) years after their respective
           issuance dates."

            2. Unless specifically modified or changed by the terms of this
Amendment, all terms and conditions of the Convertible Preferred Stock Term
Sheet shall remain in effect and shall apply fully as described and set forth in
the Convertible Preferred Stock Term Sheet.

            3. This Amendment may be executed in two or more counterparts, each
of which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

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                                                               EXECUTION VERSION

            The Company and Toucan have executed this FOURTH AMENDMENT TO
AMENDED AND RESTATED BINDING TERM SHEET as of the day and year first written
above.

TOUCAN CAPITAL FUND II, L.P.             NORTHWEST BIOTHERAPEUTICS, INC.



By:                                      By:
   ---------------------------------        ----------------------------------
Name:      Linda Powers                  Name:  Alton L. Boynton
Title:     Managing Director             Title:  President