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EXHIBIT 10.49

WELLS FARGO BANK                                   REVOLVING LINE OF CREDIT NOTE
--------------------------------------------------------------------------------
$10,000,000.00                                               OAKLAND, CALIFORNIA
                                                                    JUNE 1, 2002

        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.

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:

        a) "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.

        (b) "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.

        (c) "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.

            i. "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.

            ii. "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.

        (d) "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.

INTEREST:

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        (a) Interest. The outstanding principal balance of this Note shall bear
interest (computed on the basis of a 360-day year, actual days elapsed) either
(i) at a fluctuating rates per annum EQUAL TO the Prime Rate in effect from time
to time, or (ii) at a fixed rate per annum determined by Bank to be 1.50000%
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.

        (b) 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: (i) the
interest rate selected by Borrower; (ii) the principal amount subject to
thereto; and (iii) 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, (A)
if requested by Bank, Borrower provides to Bank written confirmation thereof not
later than three (3) Business Days after such notice is given, and (B) 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.

        (c) 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 (i) withholdings, interest equalization taxes, stamp taxes or other
taxes (except income and franchise taxes) imposed by any domestic or foreign
governmental authority and related in any manner to LIBOR, and (ii) future,
supplemental, emergency or other changes in the LIBOR Reserve Percentage,
assessment rates imposed by the Federal Deposit Insurance Corporation, or
similar requirements or costs imposed by any domestic or foreign governmental
authority or resulting from compliance by Bank with any requests or directive
(whether or not having the force of law) from any central bank or other
governmental authority and related in any manner to LIBOR to the extent they are
not included in the calculation of LIBOR. In determining which of the foregoing
are attributable to any LIBOR option available to Borrower hereunder, any
reasonable allocation made by Bank among its operations shall be conclusive and
binding upon Borrower.

        (d) Payment of Interest. Interest accrued on this Note shall be payable
on the LAST day of each MONTH, commencing JUNE 30, 2002.

        (e) Default Interest. From and after the maturity date of this Note, or
such earlier date as all principal owing hereunder becomes due and payable by
acceleration or otherwise, the outstanding principal balance of this Note shall
bear Interest until paid in full at an increased rate per annum (computed on the
basis of a 360-day year, actual days elapsed) equal to 4% above the rate of
interest from time to time applicable to this Note.

BORROWING AND REPAYMENT:

        (a) Borrowing and Repayment. Borrower may from time to time during the
term of this Note borrow, partially or wholly repay its outstanding borrowings,
and reborrow, subject to all of the limitations, terms and

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conditions of this Note and of any document executed in connection with or
governing this Note; provided however, that the total outstanding borrowings
under this Note shall not at any time exceed the principal amount stated above.
The unpaid principal balance of this obligation at any time shall be the total
amounts advanced hereunder by the holder hereof less the amount of principal
payments made hereon by or for any Borrower, which balance may be endorsed
hereon from time to time by the holder. The outstanding principal balance of
this Note shall be due and payable in full on JUNE 1, 2005.

        (b) Advances. Advances hereunder, to the total amount of the principal
sum available hereunder, may be made by the holder at the oral or written
request of (i) JOHN MONAHAN OR THOMAS J. PAULSON OR ANDREW A. SAUTER, any one
acting alone, who are authorized to request advances and direct the disposition
of any advances until written notice of the revocation of such authority is
received by the holder at the office designated above, or (ii) any person, with
respect to advances deposited to the credit of any account of any deposit
account of any Borrower, which advances, when so deposited, shall be
conclusively presumed to have been made to or for the benefit of each Borrower
regardless of the fact that persons other than those authorized to request
advances may have authority to draw against such account. The holder shall have
no obligation to determine whether any person requesting an advance is or has
been authorized by any Borrower.

        (c) Application of Payments. Each payment made on this Note shall be
credited first, to any interest then due and second, to the outstanding
principal balance hereof. All payments credited to principal shall be applied
first, to the outstanding principal balance of this Note which bears interest
determined in relation to the Prime Rate, if any, and second, to the outstanding
principal balance of this Note which bears interest determined in relation to
LIBOR, with such payments applied to the oldest Fixed Rate Term first.

PREPAYMENT:

        (a) Prime Rate. Borrower may prepay principal on any portion of this
Note which bears interest determined in relation to the Prime Rate at any time,
in any amount and without penalty.

        (b) LIBOR. Borrower may prepay principal on any portion of this Note
which bears interest determined in relation to LIBOR at any time and in the
minimum amount of $100,000.00; provided however, that if the outstanding
principal balance of such portion of this Note is less than said amount, the
minimum prepayment amount shall be the entire outstanding principal balance
thereof. In consideration of Bank providing this prepayment option to Borrower,
or if any such portion of this Note shall become due and payable at any time
prior to the last day of the Fixed Rate Term applicable thereto by acceleration
or otherwise, Borrower shall pay to Bank immediately upon demand a fee which is
the sum of the discounted monthly differences for each month from the month of
prepayment through the month in which such Fixed Rate Term matures, calculated
as follows for each such month:

        i. Determine the amount of interest which would have accrued each month
on the amount prepaid at the interest rate applicable to such amount had it
remained outstanding until the last day of the Fixed Rate Term applicable
thereto.

        ii.Subtract from the amount determined in (i) above the amount of
interest which would have accrued for the same month on the amount prepaid for
the remaining term of such Fixed Rate Term at LIBOR in effect on the date of the
prepayment for new loans made for such term and in a principal amount equal to
the amount prepaid.

        iii. If the result obtained in (ii) for any month is greater than zero,
discount that difference by LIBOR used in (ii) above.

Each Borrower acknowledges that prepayment of such amount may result in Bank
incurring additional costs, expenses and/or liabilities, and that it is
difficult to ascertain the full extent of such costs, expenses and/or
liabilities. Each Borrower, therefore, agrees to pay the above-described
prepayment fee and agrees that said amount represents a reasonable estimate of
the prepayment costs, expenses and/or liabilities of Bank. If Borrower fails to
pay any prepayment fee when due, the amount of such prepayment fee shall
thereafter bear interest until paid at the rate per annum 2.000% above the Prime
Rated in effect from time to time (computed on

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the basis of a 360-day year, actual days elapsed) Each change in the rate of
interest on any such past due prepayment fee shall become effective on the date
each Prime Rate change is announced within Bank.

EVENTS OF DEFAULT:

The occurrence of any of the following shall constitute an "Event of Default"
under this Note:

        (a) The failure to pay any principal, interest, fees or other charges
when due hereunder or under any contract, instrument or document executed in
connection with this Note.

        (b) The filing of a petition by or against any Borrower, any guarantor
of this Note or any general partner or joint venturer in any Borrower which is a
partnership or a joint venture (with each such guarantor, general partner and/or
joint venturer referred to herein as a "Third Party Obligator") under any
provisions of the Bankruptcy Reform Act, Title 11 of the United States Code, as
amended or recodified from time to time, or under any similar or other law
relating to bankruptcy, insolvency, reorganization or other relief for debtors;
the appointment of a receiver, trustee, custodian or liquidator of or for any
part of the assets or property of any Borrower or Third Party Obligor; any
Borrower or Third Party Obligor becomes insolvent, makes a general assignment
for the benefit of creditors or is generally not paying its debts as they become
due; or any attachment or like levy on any property of any Borrower or Third
Party Obligor.

        (c) The death or incapacity of any individual Borrower or Third Party
Obligor, or the dissolution or liquidation of any Borrower or Third Party
Obligor which is a corporation, partnership, joint venture or other type of
entity.

        (d) Any default in the payment or performance of any obligation, or any
defined event of default, under any provisions of any contract, instrument or
document pursuant to which any Borrower or Third Party Obligor has incurred any
obligation for borrowed money, any purchase obligation, or any other liability
of any kind to any person or entity, including the holder.

        (e) Any financial statement provided by any Borrower or Third Party
Obligor to Bank proves to be incorrect, false or misleading in any material
respect.

        (f) Any sale or transfer of all or a substantial or material part of the
assets of any Borrower or Third Party Obligor other than in the ordinary course
of its business.

        (g) Any violation or breach of any provision of, or any defined event of
default under, any addendum to this Note or any loan agreement, guaranty,
security agreement, deed of trust, mortgage or other document executed in
connection with or securing this Note.

MISCELLANEOUS:

        (a) Remedies. Upon the occurrence of any Event of Default, the holder of
this Note, at the holder's option, may declare all sums of principal and
interest outstanding hereunder to be immediately due and payable without
presentment, demand, notice of nonperformance, notice of protest, protest or
notice of dishonor, all of which are expressly waived by each Borrower, and the
obligation, if any, of the holder to extend any further credit hereunder shall
immediately cease and terminate. Each Borrower shall pay to the holder
immediately upon demand the full amount of all payments, advances, charges,
costs and expenses, including reasonable attorneys' fees (to include outside
counsel fees and all allocated costs of the holder's in-house counsel), expended
or Incurred by the holder in connection with the enforcement of the holder's
rights and/or the collection of any amounts which become due to the holder under
this Note, and the prosecution or defense of any action in any way related to
this Note, including without limitation, any action for declaratory relief,
whether incurred at the trial or appellate level, in an arbitration proceeding
or otherwise, and including any of the foregoing incurred in connection with any
bankruptcy proceeding (including without limitation, any adversary proceeding,
contested matter or motion brought by Bank or any other person) relating to any
Borrower or any other person or entity.

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        (b) Obligations Joint and Several. Should more than one person or entity
sign this Note as a Borrower, the obligations of each such Borrower shall be
joint and several.

        (c) Governing Law. This Note shall be governed by and construed in
accordance with the laws of the state of California.

IN WITNESS WHEREOF, the undersigned has executed this Note as of the date first
written above.

Avigen, Inc.

By:     /s/ THOMAS J. PAULSON
    ----------------------------------------
            Thomas J. Paulson,
            Vice President - Finance

By:     /s/ ANDREW A. SAUTER
    ----------------------------------------
            Andrew A. Sauter, Controller<PAGE>

                                                                  Exhibit 10.50

Wells Fargo
East Bay RCBO
One Kaiser Plaza, Suite 850
Oakland, CA  94612

                                  June 1, 2002

Mr. Thomas J. Paulson
Vice President - Finance
Andrew A. Sauter
Controller
Avigen, Inc.
1301 Harbor Bay Pkwy.
Alameda, CA  94502

Gentlemen:

        This letter amendment (this "Amendment") is to confirm the changes
agreed upon between WELLS FARGO BANK, NATIONAL ASSOCIATION ("Bank") and Avigen,
Inc. ("Borrower") to the terms and conditions of that certain letter agreement
between Bank and Borrower dated as of November 2, 2000, as amended from time to
time (the "Agreement"). For valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, Bank and Borrower hereby agree that the
Agreement shall be amended as follows to reflect said changes.

        1. The Agreement is hereby amended by deleting "June 1, 2002" as the
last day on which Bank will make advances under the Line of Credit, and by
substituting for said date "June 1, 2005," with such change to be effective upon
the execution and delivery to Bank of a promissory note substantially in the
form of Exhibit A attached hereto (which promissory note shall replace and be
deemed the Line of Credit Note defined in and made pursuant to the Agreement)
and al other contracts, instruments and documents required by Bank to evidence
such change. 2. Paragraph l. 1. (b) hereby deleted in its entirety, and the
following substituted therefore:

            "(b) Letter of Credit Subfeature. As a subfeature under the Line of
Credit, Bank agrees from time to time during the term thereof to issue or cause
an affiliate to issue standby letters of credit for the account of Borrower for
the account of Borrower for Financial support for the new facility at 1301
Harbor Bay Parkway, Alameda (each, a "Letter of Credit" and collectively,
"Letters of Credit"); provided however, that the aggregate undrawn amount of all
outstanding Letters of Credit shall not at any time exceed Two Million Dollars
($2,000,000.00). The form and substance for each Letter of Credit shall be
subject to approval by Bank, in its sole discretion. No Letter of Credit shall
have an expiration date subsequent to the maturity date of the Line of Credit.
The undrawn amount of all Letters of Credit shall be reserved under the Line of
Credit and shall not be available for borrowings thereunder. Each Letter of
Credit shall be subject to the additional terms and conditions of the Letter of
Credit agreements, applications and any related documents required by Bank in
connection with he issuance thereof. Each draft paid under a Letter of Credit
shall be deemed an advance under the Line of Credit and shall be repaid by
Borrower in accordance with the terms and conditions of this letter applicable
to such advances; provided however, that if advances under the Line of Credit
are not available, for any reason, at the time any draft is paid, then Borrower
shall

Avigen, Inc.
June 1, 2002
Page 2

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immediately pay to Bank the full amount of such draft, together with interest
thereon from the date such draft is paid to the date such amount is fully repaid
by Borrower, at the rate of interest applicable to advances under the Line of
Credit. In such event Borrower, at the rate of interest applicable to advances
under the Line of Credit. In such event Borrower agrees that Bank, in its amount
of any such draft."

        3. The first paragraph of Paragraph l.2.is hereby deleted in its
entirety, and the following substituted therefore:

        "As security for all indebtedness of Borrower to Bank subject hereto,
Borrower hereby grants to Bank security interests of first priority in all
Borrower's Investment Management Account #358-146238."

        4. Paragraph LL.4. is hereby deleted in its entirety, and the following
substituted therefore:

        "4. Letter of Credit Fees. Borrower shall pay to Bank (a) Fees upon the
        issuance of each Letter of Credit equal to one percent (1.0%) per annum
        (computed on the basis of a (360-day year, actual days elapsed) of the
        face amount thereof, and (b) fees upon the payment of negotiation of
        each draft under any Letter of Credit and fees upon the occurrence of
        any other activity with respect to any Letter of Credit (including
        without limitation, the transfer, amendment or cancellation of any
        Letter of Credit) determined in accordance with Bank's standard fees and
        charges then in effect for such activity."

        5. Paragraphs V.9, V.10 and V.14 are hereby deleted in their entirety,
without substitution.

        6. Paragraph V.11 is hereby deleted in its entirety, and the following
substituted therefore:

           "11. Other Indebtedness. Not create, incur, assume or permit to exist
any indebtedness or liabilities resulting from borrowings, loans or advances,
whether secured or unsecured, matured or unmatured, liquidated or unliquidated,
joint or severs, except (a) the liabilities of Borrower to Bank and (b) any
other liabilities of Borrower existing as of, and disclosed to Bank prior to,
the date hereof, in an amount not to exceed $2,000,000. in the aggregate at any
one time."

        7. Except as specifically provided herein, all terms and conditions of
the Agreement remain in full force and effect, without waiver or modification.
All terms defined in the Agreement shall have the same meaning when used herein.
This Amendment and the Agreement shall be read together, as one document.

        8. Borrower hereby remakes all representations and warranties contained
in the Agreement and reaffirms all covenants set forth therein. Borrower further
certifies that as of the date of Borrower's acknowledgement set forth below
there exists no default or defined event of default under the Agreement of any
promissory not or other contract, instrument or document executed in connection
therewith, nor any condition, act or event which with the giving of notice or
the passage of time or both would constitute such a default or defined event of
default.

Avigen, Inc.
June 1, 2002
Page 3

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        Your acknowledgment of this letter shall constitute acceptance of the
foregoing terms and conditions.

                                              Sincerely,
                                              WELLS FARGO BANK,
                                              NATIONAL ASSOCIATION

                                              By: /s/ JOSE B. HENRIQUEZ
                                                  -----------------------------
                                                  Jose B. Henriquez
                                                  Relationship Manager

Acknowledged and accepted as of     June 25, 2002       :
                               ------------------------

Avigen, Inc.

By: /s/ THOMAS J. PAULSON
    ------------------------------------------
    Thomas J. Paulson
    Vice President - Finance

By: /s/ ANDREW A. SAUTER
    ------------------------------------------
    Andrew A. Sauter
    Controller

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