SENIOR CONVERTIBLE SECURED PROMISSORY NOTE

THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”), OR APPLICABLE STATE SECURITIES LAWS. IT MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT AND APPLICABLE STATE SECURITIES LAWS OR EVIDENCE REASONABLY SATISFACTORY TO THE BORROWER THAT SUCH REGISTRATION IS NOT REQUIRED. THE SECURITIES ISSUED UPON SUCH CONVERSION MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT OR APPLICABLE STATE SECURITIES LAWS OR EVIDENCE REASONABLY SATISFACTORY TO THE BORROWER THAT SUCH REGISTRATION IS NOT REQUIRED.

FOR VALUE RECEIVED, Alteon Inc., a Delaware corporation (the “ Borrower ”), located at 6 Campus Drive, Parsippany, NJ 07054, hereby promises to pay to _______________________ (the “ Lender ”), located at ____________________________________________, or at such other place as the Lender may from time to time reasonably designate, the principal sum of ______________________ ($___________) (the “ Principal Amount ”) in lawful money of the United States, in immediately available funds, ON DEMAND, on or after May 31, 2007 (the “ Maturity Date ”), together with any additional amounts as may be required to be paid under Section 9 of this Note, unless the Principal Amount is earlier converted as set forth herein. Interest shall accrue from the date hereof until maturity (whether by demand on or after the Maturity Date or by acceleration) on the principal at a rate per annum equal to eight percent (8%), and shall be payable at maturity or upon conversion. In no event shall the rate of interest hereunder exceed the maximum interest rate permitted by applicable law.

1.   This Note is one of several notes (the “ Notes ”) in the aggregate principal amount of up to $3,000,000 and of like tenor issued by the Borrower to the Lender and others (together, the “ Lenders ”) pursuant to the terms of a Convertible Note and Warrant Purchase Agreement, dated January 11, 2007 (the “ Bridge Loan Agreement ”). By acceptance of this Note, the Lender hereby agrees that each of the Notes issued pursuant to the Bridge Loan Agreement shall rank equally and ratably without priority over one another, and the Borrower agrees that, except as expressly provided by the terms of the Notes, none of the Notes shall be paid, in whole or in part, unless an equivalent, pro rata payment is made with respect to all other Notes.

2.   As security for the payment, performance and observance of the obligations set forth in the Notes, the Borrower has agreed to grant a security interest in its assets to the collateral agent named in, and pursuant to, that certain Security & Guaranty Agreement, dated January 11, 2007 (the “ Security Agreement ”).

3.   If this Note has not previously been converted, the Borrower may repay the principal balance of this Note plus accrued but unpaid interest, together with any additional amounts as may be required to be paid under Section 9 of this Note, without penalty, at any time prior to the Maturity Date.

4.   In the event that any principal or accrued interest on this Note remains outstanding at such time as the Borrower consummates a Preferred Financing (as defined below), the entire principal balance then outstanding plus accrued but unpaid interest shall automatically be converted into the securities of the Borrower issued in a Preferred Financing at a conversion rate equal to the price per security at which the securities are issued in a Preferred Financing and with the same terms and conditions as such securities (hereinafter, an “ Automatic Conversion ”). The Automatic Conversion will be effective upon the consummation of a Preferred Financing, and the Borrower shall be relieved of any continued obligation to repay the principal or unpaid interest on this Note thereafter. The Borrower shall promptly deliver to the Lender written notification of the consummation of a Preferred Financing, and the Lender shall deliver the original of this Note to the Borrower for cancellation. The Borrower shall have no obligation to deliver securities issuable upon a Preferred Financing until such time as it receives the original of this Note or an affidavit of lost security from the Lender.

For purposes of this Note, “ Preferred Financing ” shall mean that certain contemplated transaction or series of transactions prior to the Maturity Date in which the Borrower sells shares of its preferred capital stock and warrants to purchase preferred stock to the Lenders and other investors as the Lenders may approve, in an amount up to $20,000,000, as more particularly described in the Memorandum of Proposed Terms for Private Placement of Preferred Stock and Warrants dated as of January 4, 2007.

5.   In the event that any principal or accrued interest on this Note remains outstanding at such time as Borrower consummates an Equity Financing (as defined below), the principal balance then outstanding plus accrued but unpaid interest may be converted, in whole or in part, at the election of the Lender, into the securities of the Borrower issued in the Equity Financing at a conversion rate equal to the price per security at which the securities are issued in the Equity Financing (hereinafter, a “ Voluntary Conversion ”). The Borrower shall promptly deliver to the Lender written notification of the consummation of an Equity Financing, and the Lender shall have ten (10) business days from the date of such notice to elect, by written notice to the Borrower, to convert the Note. In the event the Lender elects to convert the Note into securities issued in the Equity Financing, the Lender shall deliver the original of this Note to the Borrower for cancellation together with the election notice. The Borrower shall have no obligation to deliver securities issuable upon a Voluntary Conversion until such time as it receives the original of this Note or an affidavit of lost security from the Lender. If this Note is converted in part, the Borrower shall reissue a Note in substantially the same form to the Lender reflecting the remaining principal balance.

For purposes of this Note, “ Equity Financing ” shall mean a transaction or series of transactions in which the Borrower sells its securities which occurs after the date hereof and prior to the Maturity Date and which does not constitute a Preferred Financing.

6.   In the event that any principal or accrued interest on this Note remains outstanding prior to the Maturity Date and no Automatic Conversion or Voluntary Conversion has taken place, the principal balance then outstanding plus accrued but unpaid interest may be converted, in whole or in part, at the election of the Lender, into shares of the Borrower’s common stock, $0.01 per value per share (“ Common Stock ”), at a conversion rate equal to the closing price on the American Stock Exchange or the Nasdaq Stock Market (as reported by Bloomberg L.P. at 4:15 PM New York time)) of a share of the Borrower&