REVOLVING LINE OF CREDIT NOTE

Exhibit 10.53

     FOR VALUE RECEIVED, the undersigned AVIGEN, INC. (“Borrower”) promises to pay to the order of WELLS FARGO BANK, NATIONAL ASSOCIATION (“Bank”) at its office at EAST BAY RCBO, ONE KAISER PLAZA SUITE 850, OAKLAND, CA 94612, or at such other place as the holder hereof may designate, in lawful money of the United States of America and in immediately available funds, the principal sum of $10,000,000.00, or so much thereof as may be advanced and be outstanding, with interest thereon, to be computed on each advance from the date of its disbursement as set forth herein.

1. DEFINITIONS:

     As used herein, the following terms shall have the meanings set forth after each, and any other term defined in this Note shall have the meaning set forth at the place defined:

1.1 “Business Day” means any day except a Saturday, Sunday or any other day on which commercial banks in California are authorized or required by law to close.

1.2 “Fixed Rate Term” means a period commencing on a Business Day and continuing for 1, 2, 3 OR 6 months, as designated by Borrower, during which all or a portion of the outstanding principal balance of this Note bears interest determined in relation to LIBOR; provided however, that no Fixed Rate Term may be selected for a principal amount less than $100,000.00; and provided further, that no Fixed Rate Term shall extend beyond the scheduled maturity date hereof. If any Fixed Rate Term would end on a day which is not a Business Day, then such Fixed Rate Term shall be extended to the next succeeding Business Day.

1.3 “LIBOR” means the rate per annum (rounded upward, if necessary, to the nearest whole 1/8 of 1%) determined by dividing Base LIBOR by a percentage equal to 100% less any LIBOR Reserve Percentage.

          (a) “Base LIBOR” means the rate per annum for United States dollar deposits quoted by Bank as the Inter-Bank Market Offered Rate, with the understanding that such rate is quoted by Bank for the purpose of calculating effective rates of interest for loans making reference thereto, on the first day of a Fixed Rate Term For delivery of funds on said date for a period of time approximately equal to the principal amount to which such Fixed Rate Term applies. Borrower understands and agrees that Bank may base its quotation of the Inter-Bank Market Offered Rate upon such offers or other market indicators of the Inter-Bank Market as Bank in its discretion deems appropriate including, but not limited to, the rate offered for U.S. dollar deposits on the London Inter-Bank Market.

          (b) “LIBOR Reserve Percentage” means the reserve percentage prescribed by the Board of Governors of the Federal Reserve System (or any successor) for “Eurocurrency Liabilities” (as defined in Regulation D of the Federal Reserve Board, as amended), adjusted by Bank for expected changes in such reserve percentage during the applicable Fixed Rate Term.

1.4 “Prime Rate” means at any time the rate of interest most recently announced within Bank at its principal office as its Prime Rate, with the understanding that the Prime Rate is one of Bank’s base rates and serves as the basis upon which effective rates of interest are calculated for those loans making reference thereto, and is evidenced by the recording thereof after its announcement in such internal publication or publications as Bank may designate.

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2. INTEREST:

2.1 Interest. The outstanding principal balance of this Note shall bear interest (computed on the basis of a 360-day year, actual days elapsed) either (a) at a fluctuating rates per annum . 75000% below the Prime Rate in effect from time to time, or (b) at a fixed rate per annum determined by Bank to be . 50000% above LIBOR in effect on the first day of the applicable Fixed Rate Term. When interest is determined in relation to the Prime Rate, each change in the rate of interest hereunder shall become effective on the date each Prime Rate change is announced within the Bank. With respect to each LIBOR selection option selected hereunder, Bank is hereby authorized to note the date, principal amount, interest rate and Fixed Rate Term applicable thereto and any payments made thereon on Bank’s books and records (either manually or by electronic entry) and/or on any schedule attached to this Note, which notations shall be prima facie evidence of the accuracy of the information noted.

2.2 Selection of Interest Rate Options. At any time any portion of this Note bears interest determined in relation to LIBOR, it may be continued by Borrower at the end of the Fixed Rate Term applicable thereto so that all or a portion thereof bears interest determined in relation to the Prime Rate or to LIBOR for a new Fixed Rate Term designated by Borrower. At any time any portion of this Note bears interest determined in relation to the Prime Rate, Borrower may convert all or a portion thereof so that it bears interest determined in relation to LIBOR for a Fixed Rate Term designated by Borrower. At such time as Borrower requests an advance hereunder or wishes to select a LIBOR option for all or a portion of the outstanding principal balance hereof, and at the end of each Fixed Rate Term, Borrower shall give Bank notice specifying: (a) the interest rate option selected by Borrower; (b) the principal amount subject thereto; and (c) for each LIBOR selection, the length of the applicable Fixed Rate Term. Any such notice may be given by telephone (or such other electronic method as Bank may permit) so long as, with respect to each LIBOR selection, (i) if requested by Bank, Borrower provides to Bank written confirmation thereof not later than 3 Business Days after such notice is given, and (ii) such notice is given to Bank prior to 10:00 a.m. on the first day of the Fixed Rate Term, or at a later time during any Business Day if Bank, at it’s sole option but without obligation to do so, accepts Borrower’s notice and quotes a fixed rate to Borrower. If Borrower does not immediately accept a fixed rate when quoted by Bank, the quoted rate shall expire and any subsequent LIBOR request from Borrower shall be subject to a redetermination by Bank of the applicable fixed rate. If no specific designation of interest is made at the time any advance is requested hereunder or at the end of any Fixed Rate Term, Borrower shall be deemed to have made a Prime Rate interest selection for such advance or the principal amount to which such Fixed Rate Term applied.

2.3 Taxes and Regulatory Costs. Borrower shall pay to Bank immediately upon demand, in addition to any other amounts due or to become due hereunder, any and all (a) withholdings, interest equalization taxes, stamp taxes or other taxes (except income and franchise taxes) imposed by ay domestic or foreign governmental authority and related in any manner to LIBOR, and (b) future, supplemental, emergency or other changes in the LIBOR Reserve Percentage, assessment rates