<PAGE>
                                                                    Exhbit 10.20

EXCEPT AS SET FORTH BELOW, BENEFICIAL OWNERSHIP INTERESTS IN THIS TEMPORARY
GLOBAL NOTE WILL NOT BE EXCHANGEABLE FOR ANY NOTE REPRESENTING AN INTEREST IN
THE NOTES REPRESENTED HEREBY WHICH DO NOT CONTAIN A LEGEND CONTAINING
RESTRICTIONS ON TRANSFER, UNTIL THE EXPIRATION OF THE "40-DAY DISTRIBUTION
COMPLIANCE PERIOD" (WITHIN THE MEANING OF RULE 903(B)(2) OF REGULATION S UNDER
THE SECURITIES ACT) AND THEN ONLY UPON CERTIFICATION IN FORM REASONABLY
SATISFACTORY TO THE COMPANY THAT SUCH BENEFICIAL INTERESTS ARE OWNED EITHER BY
NON-U.S. PERSONS OR U.S. PERSONS WHO PURCHASED SUCH INTERESTS IN A TRANSACTION
THAT DID NOT REQUIRE REGISTRATION UNDER THE SECURITIES ACT. DURING SUCH 40-DAY
DISTRIBUTION COMPLIANCE PERIOD, BENEFICIAL OWNERSHIP IN THIS TEMPORARY GLOBAL
NOTE MAY ONLY BE SOLD, PLEDGED OR TRANSFERRED (1) TO THE COMPANY, (2) WITHIN THE
UNITED STATES TO A PERSON WHOM THE SELLER REASONABLY BELIEVES IS A QUALIFIED
INSTITUTIONAL BUYER (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) IN A
TRANSACTION MEETING THE REQUIREMENTS OF RULE 144A, (3) OUTSIDE THE UNITED STATES
IN A TRANSACTION IN ACCORDANCE WITH RULE 904 UNDER THE SECURITIES ACT OR (4)
PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT, IN
EACH OF THE CASES (1) THROUGH (4) IN ACCORDANCE WITH ANY APPLICABLE SECURITIES
LAWS OF ANY STATE OF THE UNITED STATES AND OTHER JURISDICTIONS. HOLDERS OF
INTERESTS IN THIS TEMPORARY GLOBAL NOTE WILL NOTIFY ANY PURCHASER OF THIS NOTE
OF THE RESALE RESTRICTIONS REFERRED TO ABOVE, IF THEN APPLICABLE.

BENEFICIAL INTERESTS IN THIS TEMPORARY GLOBAL NOTE MAY BE EXCHANGED FOR
INTERESTS IN A RESTRICTED GLOBAL NOTE ONLY IF (1) SUCH EXCHANGE OCCURS IN
CONNECTION WITH A TRANSFER OF THE NOTES IN COMPLIANCE WITH RULE 144A, AND (2)
THE TRANSFEROR OF THE REGULATION S TEMPORARY GLOBAL NOTE FIRST DELIVERS TO THE
COMPANY A WRITTEN CERTIFICATE (IN THE FORM ATTACHED TO THIS CERTIFICATE) TO THE
EFFECT THAT THE REGULATION S GLOBAL NOTE IS BEING TRANSFERRED (A) TO A PERSON
WHO THE TRANSFEROR REASONABLY BELIEVES TO BE A QUALIFIED INSTITUTIONAL BUYER
WITHIN THE MEANING OF RULE 144A, (B) TO A PERSON WHO IS PURCHASING FOR ITS OWN
ACCOUNT OR THE ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER IN A TRANSACTION
MEETING THE REQUIREMENTS OF RULE 144A AND (C) IN ACCORDANCE WITH ALL APPLICABLE
SECURITIES LAWS OF THE STATES OF THE UNITED STATES AND OTHER JURISDICTIONS.

BENEFICIAL INTERESTS IN THIS TEMPORARY GLOBAL NOTE MAY BE TRANSFERRED TO A
PERSON WHO TAKES DELIVERY IN THE FORM
<PAGE>
OF AN INTEREST IN THIS TEMPORARY GLOBAL NOTE, WHETHER BEFORE OR AFTER THE
EXPIRATION OF THE 40-DAY DISTRIBUTION COMPLIANCE PERIOD, ONLY IF THE TRANSFEROR
FIRST DELIVERS TO THE COMPANY A WRITTEN CERTIFICATE TO THE EFFECT THAT IF SUCH
TRANSFER IS BEING MADE IN ACCORDANCE WITH RULE 903 OR 904 OF REGULATION S OR
RULE 144 (IF AVAILABLE) AND THAT, IF SUCH TRANSFER OCCURS PRIOR TO THE
EXPIRATION OF THE 40-DAY DISTRIBUTION COMPLIANCE PERIOD, THE INTEREST
TRANSFERRED WILL BE HELD IMMEDIATELY THEREAFTER BY A NON U.S. PERSON.

                  AMENDED AND RESTATED 8% SENIOR NOTE DUE 2006

No. 5                                                            August 26, 2005

$2,000,000.00

     FOR VALUE RECEIVED, EpiCept Corporation, a Delaware corporation (the
"COMPANY"), hereby promises to pay to the order of EPICEPT CORPORATION, ON
BEHALF OF THE REGULATION S PURCHASERS UNDER THE PURCHASE AGREEMENT (as defined
below) and its successors and assigns (the "Holder"), the principal sum of TWO
MILLION DOLLARS ($2,000,000.00) (the "PRINCIPAL AMOUNT"), on the terms and
conditions set forth in the Amended and Restated Note Purchase Agreement, dated
as of August 26, 2005 (the "PURCHASE AGREEMENT"), among the Company and the
Purchasers identified on Annex A and Annex B thereto (the "PURCHASERS"). Subject
to the conversion, prepayment and default provisions set forth in this Note and
the Purchase Agreement, all outstanding principal and accrued and unpaid
interest under this Note shall become due and payable on October 30, 2006.

     Payments of principal of, interest on and any premium with respect to this
Note are to be made in lawful money of the United States of America by check
mailed and addressed to the registered Holder hereof at the address shown in the
register maintained by the Company for such purpose, or, at the option of the
Holder, in such manner and at such other place in the United States of America
as the Holder hereof shall have designated to the Company in writing.

     Notwithstanding any provision to the contrary in this Note, the Purchase
Agreement or any other agreement, the Company shall not be required to pay, and
the Holder shall not be permitted to contract for, take, reserve, charge or
receive, any compensation which constitutes interest under applicable law in
excess of the maximum amount of interest permitted by law.

     This Note is one of a series of Amended and Restated 8% Senior Notes Due
2006 (herein called the "AMENDED AND RESTATED NOTES") issued pursuant to the
Purchase Agreement and the existing 8% Senior Notes Due 2006 (together with the
Amended and Restated Notes, the "NOTES") and is entitled to the benefits
thereof. All capitalized terms used herein but not otherwise defined shall have
the meanings ascribed to them in the Purchase Agreement. Each Holder of this
Note will be deemed, by its acceptance hereof, to have agreed to the provisions


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<PAGE>
and to have made the representations and warranties set forth in Article 6 of
the Purchase Agreement.

     This Note is transferable only by surrender hereof in accordance with
Article 7 of the Purchase Agreement, duly endorsed or accompanied by a written
instrument of transfer duly executed by the registered Holder of this Note.

     This Note is also subject to optional prepayment, in whole or in part, at
the times and on the terms specified in the Purchase Agreement.

     This Note is also subject to mandatory prepayment on the terms specified in
the Purchase Agreement.

     Immediately prior to the Effective Time (as defined in the Merger
Agreement) of the Merger, the outstanding principal of and accrued and unpaid
interest on the Amended and Restated Notes shall automatically convert, without
further act on the part of the Holder, into shares of Common Stock at a
conversion price of $0.71.

     If the Company fails to consummate an initial public offering (the "INITIAL
PUBLIC OFFERING") and thereafter consummates a debt or equity financing with
gross proceeds to the Company of at least $15,000,000 (a "QUALIFYING
FINANCING"), then, simultaneously with the closing of such Qualifying Financing,
the outstanding principal and accrued and unpaid interest on this Note shall, at
the Holder's option, be converted into the number of securities determined by
dividing the principal amount, plus accrued and unpaid interest, outstanding at
the conversion date by the purchase or issue price of the securities sold or
issued in the Qualifying Financing. Such conversion shall occur at the lowest
price paid by any purchaser in the Qualifying Financing. To effect such
conversion, the Payee shall on or before the closing of the Qualifying Financing
become a party to all agreements between the Company and the purchasers in the
Qualifying Financing which set forth the terms and conditions of such purchase
and the Payee shall be entitled to all the rights granted to the purchasers
thereunder and subject to any restrictions or obligations imposed generally on
such purchasers. The Company will mail or cause to be mailed to the Payee a
notice specifying the date on which such Qualifying Financing is scheduled to
close. Such notice will be mailed at least twenty (20) days prior to the date of
such closing.

     If an Event of Default as defined in the Purchase Agreement occurs and is
continuing, the unpaid principal and accrued and unpaid interest on this Note
may be declared or otherwise become due and payable in the manner, at the price
(including any applicable premium) and with the effect provided in the Purchase
Agreement.

     Time is of the essence of this Note. To the fullest extent permitted by
applicable law, the Company, for itself and its legal representatives,
successors and assigns, expressly waives presentment, demand, protest, notice of
dishonor, notice of maturity, notice of non-payment, notice of protest,
presentment for the purpose of accelerating maturity, diligence in collection,
and any exemption, each in respect of this Note.

     In no event, whether by reason of acceleration of the maturity of the
amounts due under the Note or otherwise, shall interest and fees contracted for,
charged, received, paid or agreed to


                                        3
<PAGE>
be paid to the Holder exceed the maximum amount permissible under applicable
Law. If, from any circumstance whatsoever, interest and fees would otherwise be
payable to the Holder in excess of the maximum amount permissible under
applicable Law, the interest and fees shall be reduced to the maximum amount
permitted under such Law. If from any circumstance, the Holder shall have
received anything of value deemed interest by applicable Law in excess of the
maximum lawful amount, an amount equal to any excess of interest shall be
applied to the reduction of the principal amount of the Notes, in such manner as
may be determined by the Holder, and not to the payment of fees or interest, or
if such excess interest exceeds the unpaid balance of the principal amount of
the Notes, such excess shall be refunded to the Company.

     Whenever possible, each provision of this Note shall be interpreted in such
manner as to be effective and valid under applicable Law, but if any provision
of this Note is held to be prohibited by or invalid under applicable Law in any
jurisdiction, such provision shall be ineffective only to the extent of such
prohibition or invalidity, without invalidating any other provision of this
Note.

     This Note and the rights and obligations of the parties hereto shall be
deemed to be contracts under the laws of the State of Delaware and for all
purposes shall be governed by and construed and enforced in accordance with the
laws of said State, except for its rules relating to the conflict of laws.

                                      * * *


                                        4
<PAGE>
     In witness whereof, the Company has caused this Amended and Restated Note
to be executed and delivered by its respective duly authorized officer as of the
day and year and at the place set forth above.

                                        EPICEPT CORPORATION


                                        By: /s/ John V. Talley
                                            ------------------------------------
                                        Name: John V. Talley
                                        Title: Chief Executive Officer


                                        5