THIS AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT (the "Agreement") is entered into as of the 17th day of April, 2006, by and between NORTHWEST BIOTHERAPEUTICS, INC., a Delaware corporation (the "Company") and TOUCAN CAPITAL FUND II, L.P. (the "Investor")

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                                                                    Exhibit 10.4

                         NORTHWEST BIOTHERAPEUTICS, INC.
                              AMENDED AND RESTATED
                            INVESTOR RIGHTS AGREEMENT

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                         NORTHWEST BIOTHERAPEUTICS, INC.

                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

     THIS AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT (the "Agreement") is
entered into as of the 17th day of April, 2006, by and between NORTHWEST
BIOTHERAPEUTICS, INC., a Delaware corporation (the "Company") and TOUCAN CAPITAL
FUND II, L.P. (the "Investor").

                                    RECITALS

     WHEREAS, the Investor purchased shares of the Company's Series A Preferred
Stock (the "Series A Stock") pursuant to that certain Securities Purchase
Agreement (the "Purchase Agreement") dated as of January 26, 2005 and the
Investor is acquiring shares of the Company's Series A-1 Preferred Stock (the
"Series A-1 Stock" and together with Series A Stock, the "Preferred Stock")
pursuant to that certain Note Conversion Agreement (the "Conversion Agreement")
dated of even date herewith;

     WHEREAS, pursuant to the Purchase Agreement the Company and the Investor
entered into that certain Investor Rights Agreement (the "ORIGINAL AGREEMENT");

     WHEREAS, the Conversion Agreement is conditioned upon the execution and
delivery of this Agreement; and

     WHEREAS, in connection with the consummation of the Conversion Agreement,
the parties desire to enter into this Agreement in order to amend and restate
the Original Agreement and to provide Investor with the registration and other
rights as set forth below.

     NOW, THEREFORE, in consideration of these premises and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

SECTION 1. GENERAL.

     1.1 DEFINITIONS. As used in this Agreement the following terms shall have
the following respective meanings:

          (A) "EXCHANGE ACT" means the Securities Exchange Act of 1934, as
amended.

          (B) "FORM S-3" means such form under the Securities Act as in effect
on the date hereof or any successor or similar registration form under the
Securities Act subsequently adopted by the SEC which permits inclusion or
incorporation of substantial information by reference to other documents filed
by the Company with the SEC.

          (C) "HOLDER" means any person owning of record Registrable Securities
that have not been sold to the public or any assignee of record of such
Registrable Securities in accordance with Section 2.11 hereof.

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          (D) "REGISTER," "REGISTERED," and "REGISTRATION" refer to a
registration effected by preparing and filing a registration statement in
compliance with the Securities Act, and the declaration or ordering of
effectiveness of such registration statement or document.

          (E) "REGISTRABLE SECURITIES" means (a) Common Stock of the Company
issuable or issued upon conversion of the Shares and (b) any Common Stock of the
Company issued as (or issuable upon the conversion or exercise of any warrant,
right or other security which is issued as) a dividend or other distribution
with respect to, or in exchange for or in replacement of, such above-described
securities. Notwithstanding the foregoing, Registrable Securities shall not
include any securities (i) sold by a person to the public either pursuant to a
registration statement or Rule 144, (ii) sold in a private transaction in which
the transferor's rights under Section 2 of this Agreement are not assigned or
(iii) held by a Holder (together with its affiliates) if, as reflected on the
Company's list of stockholders, such Holder (together with its affiliates) holds
less than 1% of the Company's outstanding Common Stock (treating all shares of
Preferred Stock on an as converted basis), the Company has completed its Initial
Offering and all shares of Common Stock of the Company issuable or issued upon
conversion of the Shares held by and issuable to such Holder (and its
affiliates) may be sold pursuant to Rule 144 during any ninety (90) day period.

          (F) "REGISTRABLE SECURITIES THEN OUTSTANDING" shall be the number of
shares of the Company's Common Stock that are Registrable Securities and either
(a) are then issued and outstanding or (b) are issuable pursuant to then
exercisable or convertible securities.

          (G) "REGISTRATION EXPENSES" shall mean all expenses incurred by the
Company in complying with Sections 2.2, 2.4 and 2.6 hereof, including, without
limitation, all registration and filing fees, printing expenses, fees and
disbursements of counsel for the Company, reasonable fees and disbursements not
to exceed one hundred thousand dollars ($100,000) of a single special counsel
for the Holders, blue sky fees and expenses and the expense of any special
audits incident to or required by any such registration (but excluding the
compensation of regular employees of the Company which shall be paid in any
event by the Company).

          (H) "SEC" or "COMMISSION" means the Securities and Exchange
Commission.

          (I) "SECURITIES ACT" shall mean the Securities Act of 1933, as
amended.

          (J) "SELLING EXPENSES" shall mean all underwriting discounts and
selling commissions applicable to the sale.

          (K) "SHARES" shall mean the Company's Series A Stock issued pursuant
to the Purchase Agreement and Series A-1 Stock issued pursuant to the Conversion
Agreement held from time to time by the Investor and its permitted assigns and
the Capital Stock issuable upon exercise of the Warrants.

          (L) "SPECIAL REGISTRATION STATEMENT" shall mean (i) a registration
statement relating to any employee benefit plan or (ii) with respect to any
corporate reorganization or transaction under Rule 145 of the Securities Act,
any registration statements related to the

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                                                                    EXHIBIT 10.4


issuance or resale of securities issued in such a transaction or (iii) a
registration related to stock issued upon conversion of debt securities.

          (M) "WARRANTS" shall mean those certain warrants to purchase capital
stock held by the Investor dated April 26, 2004, June 11, 2004, July 30, 2004,
October 22, 2004, November 10, 2004, December 27, 2004, January 26, 2005, April
12, 2005, May 13, 2005, June 16, 2005, July 26, 2005 and September 7, 2005.

SECTION 2. REGISTRATION; RESTRICTIONS ON TRANSFER.

     2.1 RESTRICTIONS ON TRANSFER.

          (A) Each Holder agrees not to make any disposition of all or any
portion of the Shares or Registrable Securities unless and until:

               (I) there is then in effect a registration statement under the
Securities Act covering such proposed disposition and such disposition is made
in accordance with such registration statement; or

               (II) (A) The transferee has agreed in writing to be bound by the
terms of this Agreement, (B) such Holder shall have notified the Company of the
proposed disposition and shall have furnished the Company with a detailed
statement of the circumstances surrounding the proposed disposition, and (C) if
reasonably requested by the Company, such Holder shall have furnished the
Company with an opinion of counsel, reasonably satisfactory to the Company, that
such disposition will not require registration of such shares under the
Securities Act. The Company will not require any transferee pursuant to Rule 144
to be bound by the terms of this Agreement if the shares so transferred do not
remain Registrable Securities hereunder following such transfer.

          (B) Notwithstanding the provisions of subsection (a) above, no such
restriction shall apply to a transfer by a Holder that is (A) a partnership
transferring to its partners or former partners in accordance with partnership
interests, (B) a corporation transferring to an affiliate, (C) a limited
liability company transferring to its members or former members in accordance
with their interest in the limited liability company, (D) an individual
transferring to the Holder's family member or trust for the benefit of an
individual Holder; (E) any other party permitted under applicable federal and
state securities laws, provided that in each case the transferee will agree in
writing to be subject to the terms of this Agreement to the same extent as if he
were an original Holder hereunder.

          (C) Each certificate representing Shares or Registrable Securities
shall be stamped or otherwise imprinted with legends substantially similar to
the following (in addition to any legend required under applicable state
securities laws):

          THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
          SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE OFFERED, SOLD OR
          OTHERWISE TRANSFERRED, ASSIGNED, PLEDGED OR HYPOTHECATED UNLESS AND
          UNTIL REGISTERED

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          UNDER THE ACT OR UNLESS THE COMPANY HAS RECEIVED AN OPINION OF COUNSEL
          SATISFACTORY TO THE COMPANY AND ITS COUNSEL THAT SUCH REGISTRATION IS
          NOT REQUIRED.

          THE SALE, PLEDGE, HYPOTHECATION OR TRANSFER OF THE SECURITIES
          REPRESENTED BY THIS CERTIFICATE IS SUBJECT TO THE TERMS AND CONDITIONS
          OF A CERTAIN INVESTOR RIGHTS AGREEMENT BY AND BETWEEN THE STOCKHOLDER
          AND THE COMPANY. COPIES OF SUCH AGREEMENT MAY BE OBTAINED UPON WRITTEN
          REQUEST TO THE SECRETARY OF THE COMPANY.

          (D) The Company shall be obligated to reissue promptly unlegended
certificates at the request of any Holder thereof if the Company has completed
its Initial Offering and the Holder shall have obtained an opinion of counsel
(which counsel may be counsel to the Company) reasonably acceptable to the
Company to the effect that the securities proposed to be disposed of may
lawfully be so disposed of without registration, qualification and legend,
provided that the second legend listed above shall be removed only at such time
as the Holder of such certificate is no longer subject to any restrictions
hereunder.

          (E) Any legend endorsed on an instrument pursuant to applicable state
securities laws and the stop-transfer instructions with respect to such
securities shall be removed upon receipt by the Company of an order of the
appropriate blue sky authority authorizing such removal.

     2.2 DEMAND REGISTRATION.

          (A) If, at any time after the initial purchase of the Preferred Stock,
holders of at least 20% of the Registrable Securities issued or issuable upon
conversion of the Preferred Stock (the "INITIATING HOLDERS") request that the
Company file a registration statement on Form SB-2 or Form S-1 (the
"REGISTRATION STATEMENT") covering at least 10% of the Registrable Securities
issued or issuable upon conversion of the Preferred Stock (or any lesser
percentage if the anticipated aggregate offering price would exceed $2,000,000),
the Company shall cause the Registrable Securities attributable to the Preferred
Stock to be registered.

          (B) If the Investor intends to distribute the Registrable Securities
covered by their request by means of an underwriting, it shall so advise the
Company as a part of its request made pursuant to this Section 2.2 or any
request pursuant to Section 2.4 and the Company shall include such information
in the written notice referred to in Section 2.2(a) or Section 2.4(a), as
applicable. In such event, the right of any Holder to include its Registrable
Securities in such registration shall be conditioned upon such Holder's
participation in such underwriting and the inclusion of such Holder's
Registrable Securities in the underwriting to the extent provided herein. All
Holders proposing to distribute their securities through such underwriting shall
enter into an underwriting agreement in customary form with the underwriter or
underwriters selected for such underwriting by the Holders of a majority of the
Registrable Securities held by all

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Initiating Holders (which underwriter or underwriters shall be reasonably
acceptable to the Company). Notwithstanding any other provision of this Section
2.2 or Section 2.4, if the underwriter advises the Company that marketing
factors require a limitation of the number of securities to be underwritten
(including Registrable Securities) then the Company shall so advise all Holders
of Registrable Securities that would otherwise be underwritten pursuant hereto,
and the number of shares that may be included in the underwriting shall be
allocated to the Holders of such Registrable Securities on a pro rata basis
based on the number of Registrable Securities held by all such Holders
(including the Initiating Holders); provided, however, that the number of shares
of Registrable Securities to be included in such underwriting and registration
shall not be reduced unless all other securities of the Company are first
entirely excluded from the underwriting and registration. Any Registrable
Securities excluded or withdrawn from such underwriting shall be withdrawn from
the registration.

          (C) The Company shall not be required to effect a registration
pursuant to this Section 2.2:

               (I) if the Company has effected two (2) registrations pursuant to
this Section 2.2 in the preceding twelve (12) months, and such registrations
have been declared or ordered effective;

               (IV) if the Initiating Holders propose to dispose of shares of
Registrable Securities that may be immediately registered on Form S-3 pursuant
to a request made pursuant to Section 2.4 below and the Company undertakes
promptly to file such Form S-3; or

     2.3 PIGGYBACK REGISTRATIONS. The Company shall notify all Holders of
Registrable Securities in writing at least fifteen (15) days prior to the filing
of any registration statement under the Securities Act for purposes of a public
offering of securities of the Company (including, but not limited to,
registration statements relating to secondary offerings of securities of the
Company, but excluding Special Registration Statements) and will afford each
such

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Holder an opportunity to include in such registration statement all or part of
such Registrable Securities held by such Holder. Each Holder desiring to include
in any such registration statement all or any part of the Registrable Securities
held by it shall, within fifteen (15) days after the above-described notice from
the Company, so notify the Company in writing. Such notice shall state the
intended method of disposition of the Registrable Securities by such Holder. If
a Holder decides not to include all of its Registrable Securities in any
registration statement thereafter filed by the Company, such Holder shall
nevertheless continue to have the right to include any Registrable Securities in
any subsequent registration statement or registration statements as may be filed
by the Company with respect to offerings of its securities, all upon the terms
and conditions set forth herein.

          (A) UNDERWRITING. If the registration statement of which the Company
gives notice under this Section 2.3 is for an underwritten offering, the Company
shall so advise the Holders of Registrable Securities. In such event, the right
of any such Holder to include Registrable Securities in a registration pursuant
to this Section 2.3 shall be conditioned upon such Holder's participation in
such underwriting and the inclusion of such Holder's Registrable Securities in
the underwriting to the extent provided herein. All Holders proposing to
distribute their Registrable Securities through such underwriting shall enter
into an underwriting agreement in customary form with the underwriter or
underwriters selected for such underwriting by the Company. Notwithstanding any
other provision of this Agreement, if the underwriter reasonably determines, in
good faith, that marketing factors require a limitation of the number of shares
to be underwritten, the number of shares that may be included in the
underwriting shall be allocated, first, to the Company; second, to the Holders
on a pro rata basis based on the total number of Registrable Securities held by
the Holders; and third, to any stockholder of the Company (other than a Holder)
on a pro rata basis; provided, however, that no such reduction shall reduce the
amount of securities of the selling Holders included in the registration below
thirty percent (30%) of the total amount of securities included in such
registration in accordance with the immediately preceding clause. In no event
will shares of any other selling stockholder be included in such registration
that would reduce the number of shares which may be included by Holders without
the written consent of Holders of not less than a majority of the Registrable
Securities proposed to be sold in the offering. If any Holder disapproves of the
terms of any such underwriting, such Holder may elect to withdraw therefrom by
written notice to the Company and the underwriter, delivered at least ten (10)
days prior to the effective date of the registration statement. Any Registrable
Securities excluded or withdrawn from such underwriting shall be excluded and
withdrawn from the registration. For any Holder which is a partnership, limited
liability company or corporation, the partners, retired partners, members,
retired members and stockholders of such Holder, or the estates and family
members of any such partners, retired partners, members and retired members and
any trusts for the benefit of any of the foregoing person shall be deemed to be
a single "Holder," and any pro rata reduction with respect to such "Holder"
shall be based upon the aggregate amount of shares carrying registration rights
owned by all entities and individuals included in such "Holder," as defined in
this sentence.


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     2.4 FORM S-3 REGISTRATION. In case the Company shall receive from any
Holder or Holders of Registrable Securities a written request or requests that
the Company effect a registration on Form S-3 (or any successor to Form S-3) or
any similar short-form registration statement and any related qualification or
compliance with respect to all or a part of the Registrable Securities owned by
such Holder or Holders, the Company will:

          (A) promptly give written notice of the proposed registration, and any
related qualification or compliance, to all other Holders of Registrable
Securities; and

          (B) as soon as practicable, effect such registration and all such
qualifications and compliances as may be so requested and as would permit or
facilitate the sale and distribution of all or such portion of such Holder's or
Holders' Registrable Securities as are specified in such request, together with
all or such portion of the Registrable Securities of any other Holder or Holders
joining in such request as are specified in a written request given within
fifteen (15) days after receipt of such written notice from the Company;
provided, however, that the Company shall not be obligated to effect any such
registration, qualification or compliance pursuant to this Section 2.4:

               (I) if Form S-3 is not available for such offering by the
Holders, or

                (II) if the Holders, together with the holders of any other
securities of the Company entitled to inclusion in such registration, propose to
sell Registrable Securities and such other securities (if any) at an aggregate
price to the public of less than one million dollars ($1,000,000), or

          (C) Subject to the foregoing, the Company shall file a Form S-3
registration statement covering the Registrable Securities and other securities
so requested to be registered as

<PAGE>

soon as practicable after receipt of the requests of the Holders. Registrations
effected pursuant to this Section 2.4 shall not be counted as demands for
registration or registrations effected pursuant to Section 2.2.

     2.5 EXPENSES OF REGISTRATION. Except as specifically provided herein, all
Registration Expenses incurred in connection with any registration,
qualification or compliance pursuant to Section 2.2, 2.3 or 2.4 herein shall be
borne by the Company. All Selling Expenses incurred in connection with any
registrations hereunder, shall be borne by the holders of the securities so
registered pro rata on the basis of the number of shares so registered. The
Company shall not, however, be required to pay for expenses of any registration
proceeding begun pursuant to Section 2.2 or 2.3, the request of which has been
subsequently withdrawn by the Initiating Holders unless (a) the withdrawal is
based upon material adverse information concerning the Company of which the
Initiating Holders were not aware at the time of such request or (b) the Holders
of a majority of Registrable Securities agree to deem such registration to have
been effected as of the date of such withdrawal for purposes of determining
whether the Company shall be obligated pursuant to Section 2.2(c) to undertake
any subsequent registration, in which event such right shall be forfeited by all
Holders). If the Holders are required to pay the Registration Expenses, such
expenses shall be borne by the holders of securities (including Registrable
Securities) requesting such registration in proportion to the number of shares
for which registration was requested. If the Company is required to pay the
Registration Expenses of a withdrawn offering pursuant to clause (a) above, then
such registration shall not be deemed to have been effected for purposes of
determining whether the Company shall be obligated pursuant to Section 2.2 to
undertake any subsequent registration.

     2.6 OBLIGATIONS OF THE COMPANY. Whenever required to effect the
registration of any Registrable Securities, the Company shall, as expeditiously
as reasonably possible:

          (A) prepare and file within sixty (60) days of the receipt of a
request for registration of Registrable Securities with the SEC a registration
statement with respect to such Registrable Securities and use all reasonable
efforts to cause such registration statement to become effective within one
hundred twenty (120) days of such request, and keep such registration statement
effective until the Holder or Holders have completed the distribution related
thereto;

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          (B) Prepare and file with the SEC such amendments and supplements to
such registration statement and the prospectus used in connection with such
registration statement as may be necessary to comply with the provisions of the
Securities Act with respect to the disposition of all securities covered by such
registration statement for the period set forth in subsection (a) above.

          (C) Furnish to the Holders such number of copies of a prospectus,
including a preliminary prospectus, in conformity with the requirements of the
Securities Act, and such other documents as they may reasonably request in order
to facilitate the disposition of Registrable Securities owned by them.

          (D) Use its best efforts to register and qualify the securities
covered by such registration statement under such other securities or Blue Sky
laws of such jurisdictions as shall be reasonably requested by the Holders;
provided that the Company shall not be required in connection therewith or as a
condition thereto to qualify to do business or to file a general consent to
service of process in any such states or jurisdictions.

          (E) In the event of any underwritten public offering, enter into and
perform its obligations under an underwriting agreement, in usual and customary
form, with the managing underwriter(s) of such offering. Each Holder
participating in such underwriting shall also enter into and perform its
o