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                                                                   Exhibit 10.33

Wells Fargo
East Bay RCBO
One Kaiser Plaza, Suite 850
Oakland, CA  94612
                                                             November 2, 2000

Avigen, Inc.
1201 Harbor Bay Pkwy., #1000
Alameda, CA  94501

Gentlemen:

        This letter is to confirm that WELLS FARGO BANK, NATIONAL ASSOCIATION
("Bank"), subject to all terms and conditions contained herein, has agreed to
make available the credit described below to Avigen, Inc. ("Borrower"):

        1. A revolving line of credit under which Bank will make advances to
Borrower from time to time up to and including June 1, 2003, not to exceed at
any time the maximum principal amount of Ten Million Dollars ($10,000,000.00)
("Line of Credit"), the proceeds of which shall be used for working capital
requirements.



I.      CREDIT TERMS:

        1.     LINE OF CREDIT:

        (a) Line of credit note. Borrower's obligation to repay advances under
the Line of Credit shall be evidenced by a promissory note substantially in the
form of Exhibit A attached hereto ("Line of Credit Note"), all terms of which
are incorporated herein by this reference.

        (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 standby
letters of credit for the account of Borrower for financial support fir the new
facility at 1301 Harbor Bay, Alameda (each, a "Letter of Credit" and
collectively, "Letters of Credit"); provided however, that the form and
substance of each Letter of Credit shall e subject to approval by Bank, in its
sole discretion; and provided further, that the aggregate undrawn amount of all
outstanding Letters of Credit shall not at ay time exceed Two Million Dollars
($2,000,000.00). No Letter of Credit shall have an expiration date more than
three hundred sixty-five (365) days beyond the maturity date of the Line of
Credit. The undrawn amount of all Letter of Credit shall be reserved under the
Line of Credit and the additional terms and conditions of the Letter of Credit
Agreement and related documents, if any, required by Bank in connection with the
issuance thereof. Each draft paid by Bank under a Letter of Credit shall be
deemed and 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 of any draft is paid by Bank, then
Borrower shall immediately pay to Bank the full amount of such draft, together
with interest thereon from the date such amount is paid by Bank to the date such


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amount is fully repaid by Borrower, at the rate of interest applicable to
advances under the Line of Credit. In such event Borrower agrees that Bank, in
its sole discretion, may debit any deposit account maintained by Borrower with
Bank for the amount of any such draft.

        (c) Borrowing and Repayment. Borrower may from time to time during the
term of the Line of Credit borrow, partially or wholly repay its outstanding
borrowings, and reborrow, subject to all of the limitations, terms and
conditions contained herein or in the Line of Credit Note; provided however,
that the total outstanding borrowings under the Line of Credit shall not at any
time exceed the maximum principal amount available thereunder, as set forth
above.


        2.     COLLATERAL:

        As security for all indebtedness of Borrower to Bank subject hereto,
Borrower hereby grants to Bank security interests of first priority in al
Borrower's Investment Management Account #324-146238.

        All of the foregoing shall be evidenced by and subject to the terms of
such security agreements, financing statements, deeds of trust and other
documents as Bank shall reasonably require, all in form an substance
satisfactory to Bank. Borrower shall reimburse Bank immediately upon demand for
all costs and expenses incurred by bank in connection with any of the foregoing
security, including without limitation, filing and recording fees and costs of
appraisals audits and title insurance.

II.     INTEREST/FEES:

        1. Interest. The outstanding principal balance of the Line of Credit
shall bear interest and the amount of each draft paid by Bank under the Standby
Letter of Credit shall bear interest from the date such draft is paid by Bank to
the date such amount is fully repaid by Borrower, at the rat of interest set
forth in the Line of Credit note.

        2. Computation and Payment. Interest shall be computed on the basis of a
360-day year, actual days elapsed. Interest shall be payable at the times and
place set forth in each promissory or other instrument required hereby.

        3. Unused Commitment Fee. Borrower shall pay to Bank a fee equal to
twenty-five hundredths percent (.250%) per annum (computed on the basis of a
360-day year, actual days elapsed) on the average daily unused amount of the
Line of Credit, which fee shall be calculated on a monthly basis by Bank and
shall be due and payable by Borrower in arrears on the last day of each month.

        4. Letter of Credit Fees. Borrower shall pay to Bank (a) fees upon th
issuance of each Letter of Credit equal to one and twenty-five hundredths
percent (1.250%) 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 or
negotiation by Bank of each draft under 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.


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Avigen, Inc.
November 2, 2000
Page 3

        5. Collection of Payments. Borrower authorized Bank to collect all
interest and fees due under the Line of Credit by charging Borrower's deposit
account number 4142-059070 with Bank, or any other deposit account maintained by
Borrower with Bank, for the full amount thereof. Should there be insufficient
funds in any such deposit account to pay all such sums when due the full amount
of such deficiency shall be immediately due and payable by Borrower.

III.    REPRESENTATION AND WARRANTIES:

        Borrower makes the following representations and warranties to Bank,
which representations and warranties shall survive the execution of this letter
and shall continue in full force and effect until the full and final payment,
and satisfaction and discharge, of all obligations of Borrower to Bank subject
to this letter.

        1. Legal Status. Borrower is a corporation, duly organized and existing
in good standing under the laws of the State of California, and is qualified or
licensed to do business in all jurisdictions in which such qualifications or
licensing is required or in which the failure to so qualify or to be so licensed
could have a material adverse effect on Borrower

        2. Authorization and Validity. This letter and each promissory note,
contract, instrument and other document deemed necessary by Bank to evidence any
extension of credit to Borrower pursuant to the terms and conditions hereof, or
now or at any time hereafter required by or delivered to Bank in connection with
this letter ("collectively, the "Loan Documents") have been duly authorized, and
upon their execution and delivered in accordance with the provisions hereof will
constitute legal, valid and binding agreements and obligations of Borrower or
the party which executes the same, enforceable in accordance with their
respective terms.

        3. No Violation. The execution, delivery and performance by Borrower of
each of the Loan Documents do not violate any provisions of any law or
regulation, or contravene any provisions of the Article of Incorporations, or
By-Laws of Borrower, or result in a breach of or constitute a default under any
contract, obligation, indenture or other instrument to which Borrower is a party
or by which Borrower may be bound.

        4. Litigation. There are no pending, or to the best of Borrower's
knowledge threatened, actions, claims, investigations, suits or proceedings by
or before any governmental authority, arbitrator, court or administrative agency
which could have a material adverse effect on the financial condition or
operation of Borrower other than those disclosed by Borrower to Bank in writing
prior to the date hereof.

        5. Correctness of Financial Statement. The financial statement of
Borrower dated March 31, 2000, a true copy of which has been delivered by
Borrower to Bank prior to the date hereof, (a) is complete and correct and
presents fairly the financial condition of Borrower, (b) discloses all
liabilities of Borrower that are required to be reflected or reserved against
under generally accepted accounting principles, whether liquidated , fixed or
contingent , and (c) has been prepared in accordance with generally accepted
accounting principles consistently applied. Since the date of such financial
statement there has been no material adverse change in the condition or
operation of Borrower, nor has Borrower


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Avigen, Inc.
November 2, 2000
Page 4

mortgaged, pledged, granted a security interest in or otherwise encumbered any
of its assets or properties except in favor of Bank or as otherwise permitted by
Bank in writing.

        6. Income Tax Returns. Borrower has no knowledge of any pending
assessments or adjustments of its income tax payable with respect to any year.

        7. No Subordination. There is no agreement, indenture, contract or
instrument to which Borrower is a party or by which Borrower may be bound that
requires the subordination in right of payment of any of Borrower's obligations
subject to this letter to any other obligation of Borrower.

        8. Permits, Franchises. Borrower possessed, and will hereafter possess,
all permits, consents, approvals, franchises and licenses required and all
rights to trademarks, trade names, patents and fictitious names, if any,
necessary to enable it to conduct the business in which it is now engaged in
compliance with applicable law.

        9. ERISA. Borrower is in compliance in all material respects with all
applicable provisions of the Employee Retirements Income Security Act of 1974,
as amended or recodified from time to time ("ERISA"); Borrower has not violated
any provision of any defined employee plan (as defined in ERISA, has occurred
and is continuing with respect to any Plan initiated by Borrower; Borrower has
met its minimum funding requirements under ERISA with respect to each Plan; and
each Plan will be able to fulfill its benefit obligations as they come due in
accordance with the Plan documents and under generally accepted accounting
principles.

        10. Other Obligations. Borrower is not in default on any obligation for
borrowed money, any purchase money obligation or any other material lease,
commitment, contract, instrument or obligation.

        11. Environmental Matters. Except as disclosed by Borrower to Bank in
writing prior to the date hereof, Borrower is in compliance in all material
respects with all applicable federal or state environmental, hazardous waste,
health and safety statutes, and any rules or regulations adopted pursuant
thereto, which govern or affect any of Borrower's operations and/or properties,
including without limitation, the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, the Superfund Amendments and
Reauthorization Act of 1986, the Federal Resource Conservation and Recovery Act
of 1976, and the Federal Toxic Substances Control Act, as any of the same may be
amended, modified or supplemented from investigation evaluating whether any
remedial action involving a material expenditure is needed to respond to a
release of any toxic or hazardous waste or substance into the environment.
Borrower has no material contingent liability in connection with any release of
any toxic or hazardous waste or substance into the environment.

IV.     CONDITIONS:

        1. Conditions of Initial Extension of Credit. The obligation of Bank to
extend any credit contemplated by this letter is subject to fulfillment of
Bank's satisfaction of all of the following conditions:


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Avigen, Inc.
November 2, 2000
Page 5

        (a) Documentation. Bank shall have received each of the Loan Documents,
duly executed and in form and substance satisfactory to Bank.

        (b) Financial Condition. There shall have been no material adverse
change, as determined by Bank, in the financial condition or business of
Borrower, nor any material decline, as determined by Bank, in the market value
of any collateral required hereunder or a substantial or material portion of the
assets of Borrower.

        2. Conditions of Each Extension of Credit. The obligation of Bank to
make each extension of credit requested by Borrower hereunder shall be subject
to the fulfillment to Bank's satisfaction of each of the following conditions:

        (a) Compliance. The representations and warranties contained herein and
in each of the other Loan Documents shall be true on and as of the date of the
signing of this letter and on the date of each extension credit by Bank pursuant
hereto, with the same effect as thought such representations and warranties had
been made on and as of each such date, and on each such date, no default
hereunder and no condition, event or act which with the giving of notice or the
passage of time or both would constitute such a default, shall have occurred and
be continuing or shall exist.

        (b) Documentation. Bank shall have received all additional documents
which may be required in connection with such extension of credit


V.      COVENANTS:

        Borrower covenants that so long Bank remains committed to extend credit
to Borrower pursuant hereto, or any liabilities (whether direct or contingent,
liquidated or unliquidated) of Borrower to Bank under any of the Loan Documents
remain outstanding, and until payment in full of all obligations of Borrower
subject hereto, Borrower shall, unless Bank otherwise consents in writing:

        1. Punctual Payment. Punctually pay all principal, interest, fees or
other liabilities due under any of the loan Documents at the times and place an
in the manner specified therein.

        2. Accounting Records. Maintain adequate books and records in accordance
with generally accepted accounting principles consistently applied, and permit
any representative of Bank, at any reasonable time, to inspect, audit and
examine such books and records, to make copies of the same and inspect the
properties of Borrower.

        3. Financial Statements. Provide to Bank all of the following, in form
and detail satisfactory to Bank:

        (a) not later than 120 days after and as of the end of each fiscal year,
a copy of 10K report filed with the Securities Exchange Commission, prepared by
a certified public accountant acceptable to Bank, to include balance sheet and
income statement;


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Avigen, Inc.
November 2, 2000
Page 6

        (b) not later than 60 days after and as of the end of each fiscal
quarter, a copy of 10Q report filed with the Securities Exchange Commission,
prepared by Borrower, to include balance sheet and income statement; and

        (c) from time to time such other information as Bank my reasonably
request.

        4. Compliance. Preserve and maintain all licenses, permits, governmental
approvals, rights, privileges and franchises necessary for the conduct of its
business; and comply with the provisions of all documents pursuant to which
Borrower is organized and/or which govern Borrower's continued existence and
with the requirements of all laws, rules, regulations and orders of a
governmental agency applicable to Borrower and/or its business.

        5. Insurance. Maintain and keep in force insurance of the types and in
amounts customarily carried in lines of business similar to that of Borrower,
including but not limited to fire, extended coverage, public liability, flood,
property damage and worker's compensation, with all such insurance carried with
companies and in amounts satisfactory to Bank, and deliver to Bank from time to
time at Bank's request schedules setting forth all insurance then in effect.

        6. Facilities. Keep all properties useful or necessary to Borrower's
business in good repair and condition, and from time to time make necessary
repairs, renewals and replacements thereto so that such properties shall be
fully and efficiently preserved and maintained.

        7. Taxes and Other Liabilities. Pay and discharge when due any and all
indebtedness, obligations, assessments and taxes, both real or personal,
including without limitation federal and state income taxes and state and local
property taxes and assessments, except (a) such as Borrower may in good faith
contest or as to which a bona fide dispute may arise, and (b) for which Borrower
had made provision, to Bank's satisfaction, for eventual payment thereof in the
event Borrower is obligated to make such payment.

        8. Litigation. Promptly give notice in writing to Bank of any litigation
pending or threatened against Borrower.

        9. Financial Condition Maintain Borrower's financial condition as
follows using generally accepted accounting principles consistently applied and
used consistently with prior practices (except to the extent modified by the
definitions herein):

        (a) Liquid Assets not at any time less than $4,000,000.00, with "Liquid
Assets" defined as Overland money market duns, plus market value of AP-P1
commercial paper, US government bonds, notes and bills and municipal and
corporate bonds rated BBB or better.

        10. Operating Account. Maintain at all times a minimum of $1,500,000.00
in Borrower's operating account at Bank, which operating account shall be linked
through Bank's credit sweep, to an Overland money market fund.

        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 several, except (a) the liabilities of


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Avigen, Inc.
November 2, 2000
Page 7

Borrower to Bank, and (b) any other liabilities of Borrower existing as of, and
disclosed to Bank prior to, the date hereof.

        12. Merger, Consolidation, Transfer of Assets. Not merge into or
consolidate with any other entity; nor make any substantial change in the nature
of Borrower's business as conducted as of the date hereof; nor acquire all or
substantially all of the assets of any other entity; nor sell, lease, transfer
or otherwise dispose of all or a substantial or material portion of Borrower as
security for, any liabilities or obligations of any other person or entity,
except any of the foregoing in favor of Bank.

        13. Guaranties. Not guarantee or become liable in any way as surety,
endorser (other than as endorser of negotiable instruments for deposit or
collection in the ordinary course of business), accommodation endorser or
otherwise for, nor pledge or hypothecate any assets of Borrower as security for,
any liabilities or obligations of any other person or entity, except any of the
foregoing in favor of Bank.

        14. Loans, Advances, Investments. Not make any loans or advances to or
investments in any person or entity, except any of the foregoing existing as of,
and disclosed to Bank prior to, the date thereof.

        15. Pledge of Assets. Not mortgage pledge, grant or permit to exist a
security interest in, or lien upon, all or any portion of Borrower's asset now
owned or hereafter acquired, except any of the foregoing in favor of Bank or
which are existing as of, and disclosed to Bank in writing prior to, the date
hereof.


VI.     DEFAULT, REMEDIES:

        1. Default, Remedies. Upon the violation of any term or condition of any
of the Loan Documents, or upon the occurrence of any default or defined event of
default under any of the Loan Documents: (a) all indebtedness of Borrower under
each of the Loan Documents, any term thereof to the contrary notwithstanding,
shall at Bank's option and without notice become immediately due and payable
without presentment, demand, protest or notice of dishonor, all of which are
expressly waive by Borrower; (b) the obligation, if any, of Bank to extend any
further credit under any of the Loan Documents shall immediately cease and
terminate; and (c) Bank shall have all rights, powers and remedies available
under each of the Loan Documents, or accorded by law, including without
limitation the right to resort to any or all security for any credit subject
hereto and to exercise any or all of the rights of a beneficiary or secured
party pursuant to applicable law. All rights, powers and remedies of Bank may be
exercised at any time by Bank and from time to time after the occurrence of any
such breach or default, are cumulative and not exclusive, and shall be in
addition to any other rights, powers or remedies provided by law or equity.

        2. No Waiver. No delay, failure or discontinuance of Bank in exercising
any right, power or remedy under any of the Loan Documents shall affect or
operate as a waiver os such right, power or remedy; nor shall any single or
partial exercise of any such right, power or remedy preclude, waive or otherwise
affect any other or further exercise thereof or the exercise of any other right,
power or remedy. Any waiver, permit, consent or approval of any


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Avigen, Inc.
November 2, 2000
Page 8

kind by Bank of any breach of or default under any of the Loan Documents must be
in writing and shall be effective only to the extend set forth in such writing.


VII.    MISCELLANEOUS:


        1. Notices. All notices, requests and demands which any party is
required or may desire to give to any other party under any provision of this
letter must e in writing delivered to each party at its address first set forth
above, or to such other address a any party may designate by written notice to
all other parties. Each such notice, request and demand shall be deemed given or
made as follows: (a) if sent by hand delivery, upon delivery; (b) if sent by
mail, upon the earlier of the date of receipt or three (3) days after deposit in
the U.S. mail, first class and postage prepaid; and (c) if sent by telecopy,
upon receipt.

        2. Costs, Expenses and Attorney's Fees. Borrower shall pay to Bank
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 Bank's in-house counsel), expended or incurred
by Bank in connection with (a) the negotiation and preparation of this letter
and the other Loan Documents, Bank's continued administration hereof and
thereof, and the preparation of amendments and waivers hereto and thereto, (b)
the enforcement of Bank's rights and/or the collection of any amounts which
become due to Bank under any of the Loan Documents, and (c) the prosecution or
defense of any action in any way related to any the Loan Documents, 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.

        3. Successors, Assignment. This letter shall be binding upon and insure
to the benefit of the heirs, executors, administrators, legal representatives,
successors and assigns of the parties; provided however, that Borrower may not
assign or transfer its interest hereunder without Bank's prior written consent.
Bank reserves the right to sell, assign, transfer, negotiate or grant
participation in all or any part of, or any interest in, Bank's rights and
benefits under each of the Loan Documents. In connection therewith Bank may
disclose all documents and information which Bank now has or hereafter may
acquire relating to any credit subject hereto, Borrower or its business, or any
collateral required hereunder.

        4. Entire Agreement; Amendment. This letter and the other Loan Documents
constitute the entire agreement between Borrower and Bank with respect to each
credit subject hereto and supersede all prior negotiations, communications,
discussions and correspondence concerning the subject matter hereof. This letter
may be amended or modified only in writing signed by each party hereto.

        5. No Third Party Beneficiaries. This letter is made and entered into
for the sole protection and benefit of the parties hereto and their respective
permitted successors and assigns, and no other person or entity shall be a third
party beneficiary of, or have any direct


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Avigen, Inc.
November 2, 2000
Page 9

or indirect cause of action or claim in connection with, this letter or any
other of the Loan Documents to which it is not a party.

        6. Severability of Provisions. If any provision of this letter shall be
prohibited or invalid under applicable law, such provision shall be ineffective
only to the extent of such prohibition or invalidity without invalidating the
remainder of such provision or any remaining provisions of this letter.

        7. Governing Law. This letter shall be governed by and construed in
accordance with the laws of the State of California.

        8. Arbitration.

        (a) Arbitration. Upon the demand of any party, any Dispute shall be
resolved by binding arbitration in accordance with the terms of this letter. A
"Dispute" shall mean any action, dispute, claim or controversy of any kind,
whether in contract or tort, statutory or common law, legal or equitable, now
existing or hereafter arising under or in connection with, or in any way
pertaining to, any of the Loan Documents or any past, present or future
extensions of credit and other activities, transactions or obligations of any
kind related directly or indirectly to any of the Loan Documents, including
without limitation, any of the foregoing arising in connection with the exercise
of any self-help, ancillary or other remedies pursuant to any of the Loan
Documents. Any party may by summary proceedings bring an action in court to
compel arbitration of a Dispute. Any party who fails or refuses to submit to
arbitration following a lawful demand by any other party shall bear all costs
and expenses incurred by such other party in compelling arbitration of any
Dispute.

        (b) Governing Rules. Arbitration proceedings shall be administered by
the American Arbitration Association ("AAA") or such other administrator as the
parties shall mutually agree upon in accordance with the AAA Commercial
Arbitration Rules. All Disputes submitted to arbitration shall be resolved in
accordance with the Federal Arbitration Act (Title 9 of the United States Code),
not withstanding any conflicting choice of law provision in any of the Loan
Documents. The arbitration shall be conducted at a location in California
selected by the AAA or other administrator. If there is any inconsistency
between the terms hereof and any such rules, the terms and procedures set forth
herein shall control. All discovery activities shall be expressly limited to
matters directly relevant tot the Dispute being arbitrated. Judgment upon any
award rendered in an arbitration may be entered in any court having
jurisdiction; provided however, that nothing contained herein shall be deemed to
be a waiver by any party that is a bank of the protections afforded to it under
12 U.S.C. Section 91 or similar applicable state law.

        (c) No Waiver, Provisional Remedies, Self-Help and Foreclosure. No
provision hereof shall limit the right of any party to exercise self-help
remedies such as setoff, foreclosure against or sale of any real or personal
property collateral or security, or to obtain provisional or ancillary remedies,
including without limitation injunctive relief, sequestration, attachment,
garnishment or the appointment of a receiver, from a court of competent
jurisdiction before, after or during the pendency of any arbitration or other
proceeding. The exercise of any such remedy shall not waive the right of any
party to compel arbitration or reference hereunder.


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Avigen, Inc.
November 2, 2000
Page 10

        (d) Arbitrator Qualifications and Powers; Awards. Arbitrators must be
active members of the California State Bar or retired judges of the state or
federal judiciary of California, with expertise in the substantive law
applicable to the subject matter of the Dispute. Arbitrators are empowered to
resolve Disputes by summary rulings in response to motions filed prior to the
final arbitration hearing. Arbitrators (i) shall resolve all Disputes in
accordance with the substantive law of the State of California, (ii) may grant
any remedy or relief that a court of the State of California could order or
grant within the scope hereof and such ancillary relief as is necessary to make
effective any award, and (iii) shall have the power to award recovery of all
costs and fees, to impose sanctions and to take sanctions and to take such other
actions as they deem necessary to Rules of Civil Procedure or other applicable
law. Any Dispute in which the amount in award of greater than $5,000,000 shall
be decided by majority vote of a panel of three arbitrators; provided however,
that all three arbitrators must actively participate in all hearings and
deliberations.

        (e) Real Property Collateral; Judicial Reference. Notwithstanding
anything herein to the contrary, no Dispute shall be submitted to arbitration if
the Dispute concerns indebtedness secured directly or indirectly, in whole or in
part, by any real property unless (i) the holder of the mortgage, lien or
security interest specifically elects in writing to proceed with the
arbitration, or (ii) all parties to the arbitration waive any rights or benefits
that might accrue to them by virtue of the single action rule statute of
California, thereby agreeing that all indebtedness and obligations of the
parties, and all mortgages, liens and security interests securing such
indebtedness and obligations, shall remain fully valid and enforceable. If any
such Dispute is not submitted to arbitration, the Dispute shall be referred to a
referee with the qualifications required herein for arbitrators shall be
selected pursuant to the AAA's selection procedures. Judgment upon the decision
rendered by a referee shall be entered in the court in which such proceeding was
commenced in accordance with California Code of Civil Procedure Sections 644 and
645.

        (f) Miscellaneous. To the maximum extent practicable, the AAA, the
arbitrators and the parties shall take all action required to conclude any
arbitration proceeding within 180 days of the filing of the Dispute with the
AAA. No arbitrator or other party to an arbitrator proceeding may disclose the
existence, content or results thereof, except for disclosures of information by
a party required in the ordinary course of its business, by applicable law or
regulation, or to the extent necessary to exercise any judicial review rights
set forth herein. If more than one agreement for arbitration by or between the
parties potentially applies to a Dispute, the arbitration provision most
directly related to the Loan Documents or the subject matter of the Dispute
shall control. This arbitration provision shall survive termination, amendment,
or expiration of any of the Loan Documents or any relationship between the
parties.

        Your acknowledgment of this letter shall constitute acceptance of the
foregoing terms and conditions. Bank's commitment to extend any credit to
Borrower pursuant to the terms of this letter shall terminate on November 30,
2000, unless this letter is acknowledges by Borrower and returned to Bank on or
before that date.

                                    Sincerely,
                                    WELLS FARGO BANK,
                                    NATIONAL ASSOCIATION

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Avigen, Inc.
November 2, 2000
Page 11



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

     Acknowledged and accepted as of 11/8/00.

Avigen, Inc.

By: /s/ THOMAS J. PAULSON
    ------------------------------------------
    Thomas J. Paulson, Chief Financial Officer

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