EXHIBIT 4.4

                               STOCK PURCHASE AGREEMENT

               THIS STOCK PURCHASE AGREEMENT (the "Agreement") is made as of the
22nd day of January, 1999, by and between VICAL INCORPORATED, a Delaware
corporation (the "Company"), and PFIZER INC, a Delaware corporation
("Investor").

               THE PARTIES HEREBY AGREE AS FOLLOWS:

               1.   PURCHASE AND SALE OF STOCK.

               1.1  SALE AND ISSUANCE OF COMMON STOCK.  Subject to the terms 
and conditions of this Agreement, Investor hereby purchases and the Company 
hereby sells and issues to Investor 317,969 shares (the "Shares") of Common 
Stock for the purchase price per share equal to 125% of the average of the 
closing prices reported by the Nasdaq National Market System for the fifteen 
(15) consecutive trading days prior to, but not including, the Closing Date, 
for an aggregate purchase price of $6,000,000 (the "Purchase Price").

               1.2  CLOSING.  The purchase and sale of the Common Stock shall 
take place at the offices of the Company, 9373 Towne Centre Drive, San Diego, 
California, at 10 A.M., on the date that the Collaborative Research and 
Option Agreement between the Company and Investor, dated the date hereof, 
becomes effective, or at such other times and places as the Company and 
Investor mutually agree upon, verbally or in writing (which times and places 
are designated as the "Closing"). At the Closing, the Company shall instruct 
its transfer agent, ChaseMellon Shareholder Services L.L.C., to deliver 
promptly to Investor a certificate representing the Common Stock which such 
Investor is purchasing against delivery to the Company by such Investor of a 
bank wire in same day funds in the amount of the Purchase Price therefor 
payable to the Company's order.

               1.3  DEFINITIONS.

               (a)  The following terms, as used herein, have the following
meanings:

               "Closing Date" means the date of the Closing.

               "Common Stock" means the Common Stock, par value $0.01 per 
share of the Company, together with the associated preferred stock purchase 
rights established pursuant to the Rights Agreement dated March 20, 1995 
between the Company and ChaseMellon Shareholder Services L.L.C. as rights 
agent.

               "Material Adverse Effect" means a material adverse 


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effect on the condition (financial or otherwise), business,assets, results of 
operations of a corporation and its subsidiaries taken as a whole.

               "1934 Act" means the Securities Exchange Act of 1934, as 
amended, and the rules and regulations promulgated thereunder.

               "1933 Act" means the Securities Act of 1933, as amended, and 
the rules and regulations promulgated thereunder.

               "Person" shall mean an individual, corporation, partnership, 
trust, business trust, association, joint stock company, joint venture, pool, 
syndicate, sole proprietorship, unincorporated organization, governmental 
authority or any other form of entity not specifically listed herein.

               "SEC" shall mean the U.S. Securities and Exchange Commission.

               2.   REPRESENTATIONS AND WARRANTIES OF THE COMPANY.  The 
Company hereby represents and warrants to Investor that:

               2.1  ORGANIZATION, GOOD STANDING AND QUALIFICATION.  The 
Company is a corporation duly organized, validly existing and in good 
standing under the laws of the State of Delaware and has all requisite 
corporate power and authority to carry on its business as now conducted. The 
Company is duly qualified to transact business and is in good standing in 
each jurisdiction in which the failure so to qualify would have a Material 
Adverse Effect.

               2.2  CAPITALIZATION.  The authorized capital of the Company 
consists of:

               (a)  PREFERRED STOCK.  5,000,000 shares of Preferred Stock, of 
which 40,000 shares have been designated Series A Participating Preferred 
Stock, par value $.01 per share. There are no shares of Series A 
Participating Preferred Stock issued and outstanding.

               (b)  COMMON STOCK.  40,000,000 shares of Common Stock, of 
which 15,836,028 shares were issued and outstanding on December 4, 1998.

               2.3  AUTHORIZATION.  All corporate action on the part of the 
Company, its officers, directors and stockholders necessary for (i) the 
authorization, execution and delivery of this Agreement, (ii) the performance 
of all obligations of the Company hereunder and (iii) the authorization, 
issuance (or reservation for issuance) and delivery of the Common Stock being 
sold hereunder, to the extent that the foregoing requires performance on or 
prior to the Closing, has been taken and this Agreement constitutes the valid 
and legally binding obligation


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of the Company, enforceable against the Company in accordance with its terms.

               2.4  VALID ISSUANCE OF COMMON STOCK.  The Common Stock 
purchased by the Investor hereunder has been duly and validly issued and is 
fully paid and nonassessable and, based in part upon the representations of 
the Investor in this Agreement, was issued in compliance with all applicable 
federal and state securities laws.

               2.5  SEC FILINGS.  The Company has registered its Common Stock 
pursuant to Section 12 of the 1934 Act, and the Common Stock is quoted on the 
Nasdaq National Market. The Company has filed all forms, reports and 
documents required to be filed pursuant to the federal securities laws and 
the rules and regulations promulgated thereunder for a period of at least 
twelve (12) months immediately preceding the offer or sale of the Shares. The 
Company's filings with the SEC complied as of their respective filing dates, 
or in the case of registration statements, their respective effective dates, 
in all material respects with all applicable requirements of the 1933 Act and 
the 1934 Act and the rules and regulations promulgated thereunder. None of 
such filings, including, without limitation, any exhibits, financial 
statements or schedules included therein, at the time filed, or in the case 
of registration statements, at their respective filing dates, contained any 
untrue statement of a material fact or omitted to state a material fact 
required to be stated therein or necessary to make the statements therein, in 
light of the circumstances under which they were made, not misleading.

               2.6  LITIGATION.  Except as disclosed in the Company's filings 
with the SEC, there is no action, suit or proceeding before or by any court 
or governmental agency or body, domestic or foreign, now pending or, to the 
knowledge of the Company, threatened, against or affecting the Company, or 
any of its properties, which might result in any material adverse change in 
the condition (financial or otherwise) or in the earnings, business affairs 
or business prospects of the Company, or which might materially and adversely 
affect the properties or assets thereof.

               2.7  NO DEFAULT.  Except as disclosed in the Company's filings 
with the SEC, the Company is not in default in the performance or observance 
of any material obligation, agreement, covenant or condition contained in any 
indenture, mortgage, deed of trust or other material agreement or instrument 
to which it is a party or by which it or its property may be bound, except 
for defaults that have not had and would not reasonably be expected to have, 
individually or in the aggregate, a Material Adverse Effect.

               2.8  SUBSEQUENT EVENTS.  Since September, 1998, (i) the 
Company has incurred no liability or obligation, contingent 


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or otherwise, that taken as a whole, is material in the aggregate to the 
Company, except in the ordinary course of business, and (ii) there has been 
no material adverse change in the condition or results of operations, 
financial or otherwise, of the Company, taken as a whole.

               2.9  CONSENTS AND APPROVALS.   No consent, approval, 
qualification, order or authorization of, or filing with, any local, state or 
federal governmental authority or any third party is required on the part of 
the Company in connection with the Company's valid execution, delivery or 
performance of this Agreement, or the offer, sale or issuance of the Shares 
by the Company, other than the filings that have been made prior to the 
Closing, except that any notices of sale required to be filed by the Company 
with the SEC under Regulation D of the 1933 Act, or such post-closing filings 
as may be required under applicable state securities laws, which will be 
timely filed within the applicable periods therefor.

               2.10 COMPLIANCE WITH LAWS AND COURT ORDERS.  The Company is 
not in violation of any applicable law, rule, regulation, judgment, 
injunction, order or decree except for violations that have not had and would 
not reasonably be expected to have, individually or in the aggregate, a 
Material Adverse Effect.

               3.   REPRESENTATIONS AND WARRANTIES OF INVESTOR.  This 
Agreement is made with Investor in reliance upon the Investor's 
representation and warranties to the Company, which by such Investor's 
execution of this Agreement the Investor hereby confirms, that:

               3.1  ORGANIZATION AND EXISTENCE.  Investor is a corporation 
duly incorporated, validly existing and in good standing under the laws of 
Delaware and has all corporate powers and all material governmental licenses, 
authorizations, permits, consents and approvals required to carry on its 
business as now conducted, except for those licenses, authorizations, 
permits, consents and approvals the absence of which would not, individually 
or in the aggregate, have a Material Adverse Effect.

               3.2  CORPORATE AUTHORIZATION.  The execution, delivery and 
performance by Investor of this Agreement are within the corporate powers of 
Investor and have been duly authorized by all necessary corporate action on 
the part of Investor. This Agreement constitutes its valid and legally 
binding obligation, enforceable in accordance with its terms.

               3.3  PURCHASE ENTIRELY FOR OWN ACCOUNT.  The Common Stock to 
be received by Investor will be acquired for investment for Investor's own 
account, not as a nominee or agent, and not with a view to the resale or 
distribution of any part thereof, and that Investor has no present intention 
of selling, granting


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any participation in, or otherwise distributing the same. By executing this 
Agreement, Investor further represents that Investor does not have any 
contract, undertaking, agreement or arrangement with any person to sell, 
transfer or grant participation to such person or to any third person, with 
respect to any of the Common Stock.

               3.4  CONFIDENTIALITY.  Investor hereby represents, warrants 
and covenants that it shall maintain as confidential all information provided 
to it by the Company hereunder.

               3.5  RESTRICTED SECURITIES.  Investor understands that the 
shares of Common Stock it is purchasing are characterized as "restricted 
securities" under the federal securities laws inasmuch as they are being 
acquired from the Company in a transaction not involving a public offering 
and that under such laws and applicable regulations such securities may be 
resold without registration under the 1933 Act only under certain limited 
circumstances. In this connection Investor represents that it is familiar 
with SEC Rule 144, as presently in effect, and understands the resale 
limitations imposed thereby and by the 1933 Act.

               3.6  LEGENDS.  It is understood that the certificates 
evidencing the Common Stock may bear one or all of the following legends:

               (a)  "These securities have not been registered under the 
Securities Act of 1933. They may not be sold, offered for sale, pledged or 
hypothecated in the absence of a registration statement in effect with 
respect to the securities under such Act or an opinion of counsel 
satisfactory to Vical Incorporated that such registration is not required or 
unless sold pursuant to Rule 144 of such Act."

               (b)  If required by the authorities of any state in connection 
with the issuance or sale of the Common Stock the legend required by such 
state authority.

               3.7  REMOVAL OF LEGENDS.

               (a)  Any legend endorsed on a certificate pursuant to 
Subsection 3.6(a) shall be removed (i) if the shares of Common Stock 
represented by such certificate shall have been resold under an effective 
registration statement under the 1933 Act or otherwise lawfully sold in a 
public transaction, (ii) if such shares may be transferred in compliance with 
Rule 144(k) promulgated under the 1933 Act, or (iii) if the holder of such 
shares shall have provided the Company with an opinion of counsel, in form 
and substance acceptable to the Company and its counsel, stating that a 
public sale, transfer or assignment of such shares may be made without 
registration.


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               (b)  Any legend endorsed on a certificate pursuant to 
Subsection 3.6(b) shall be removed if the Company receives an order of the 
appropriate state authority authorizing such removal or if the holder of such 
shares provides the Company with an opinion of counsel, in form and substance 
acceptable to the Company and its counsel, stating that such state legend may 
be removed.

               4.   ADDITIONAL DELIVERIES TO INVESTOR AT CLOSING.  The 
obligations of Investor under Subsection 1.1 of this Agreement are subject to 
the fulfillment on or before the Closing of each of the following conditions, 
the waiver of which shall not be effective if such Investor does not consent 
in writing thereto:

               4.1  COMPLIANCE CERTIFICATE.  The President or a Vice 
President of the Company shall deliver to Investor at the Closing a 
certificate stating that there has been no material adverse change in the 
business, affairs, prospects, operations, properties, assets or condition of 
the Company since September 30, 1998 other than because of operating losses 
and changes in the ordinary course of business.

               4.2  SECRETARY'S CERTIFICATE.  The Secretary of the Company 
shall deliver to Investor at the Closing a certificate certifying that 
attached thereto are true and complete copies of each of the following 
documents:

               (a)  Restated Certificate of Incorporation as in effect on the 
Closing Date, of the Company;

               (b)  Bylaws, as amended as in effect on the Closing Date, of 
the Company; and

               (c)  Copies of the resolutions of the Company's Board of 
Directors authorizing the execution and delivery of this Agreement and the 
performance by the Company of the transactions contemplated herein.

               4.3  HSR ACT.  If applicable, the waiting period under the 
Hart-Scott-Rodino Antitrust Improvements Act of 1976, including any 
extensions of said waiting period, shall have expired and any investigations 
relating to the transactions contemplated herein that may have been opened by 
either the Department of Justice or the Federal Trade Commission (by means of 
a request for additional information or otherwise) shall have been terminated.

               5.   REGISTRATION RIGHTS.  The Company covenants and agrees as 
follows:

               5.1  CERTAIN ADDITIONAL DEFINITIONS.  As used in this 
Agreement, the following capitalized terms shall have the following meanings:


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               "PROSPECTUS" shall mean the prospectus included in any 
Registration Statement, as amended or supplemented by any prospectus 
supplement with respect to the terms of the offering of any portion of the 
Registrable Securities covered by such Registration Statement and by all 
other amendments and supplements to the prospectus, including post-effective 
amendments and all material incorporated by reference in such prospectus.

               "REGISTER," "REGISTERED" and "REGISTRATION" refer to a 
registration effected by preparing and filing a registration statement or 
similar document in compliance with the 1933 Act, and such registration 
statement or document becoming effective under the 1933 Act.

               "REGISTRABLE SECURITIES" shall mean (i) the Common Stock 
purchased by the Investor pursuant to this Agreement; and (ii) any Common 
Stock issued as (or issuable upon the conversion or exercise of any warrant, 
right or other security which is issued as) a dividend or other distribution 
with respect to, or in exchange for or in replacement of, such Common Stock.

               "REGISTRATION STATEMENT" shall mean any registration statement 
of the Company that covers any of the Registrable Securities pursuant to the 
provisions of this Agreement, including the Prospectus, amendments and 
supplements to such Registration Statement, including post-effective 
amendments, all exhibits and all material incorporated by reference in such 
Registration Statement.

               5.2  REGISTRATION.  The Company will use its reasonable best 
efforts to effect a registration to permit the sale of the Registrable 
Securities as described below, and pursuant thereto the Company will:

               (a)  prepare and file at such time as is mutually agreed upon 
by the Company and Investor, and use its reasonable best efforts to 
thereafter have declared effective by the SEC, a Registration Statement on 
Form S-3 (or if the use of Form S-3 or any successor form is unavailable, on 
another appropriate form, including but not limited to, Forms S-1, S-2 or 
their successor forms) relating to resale of all of the shares of the 
Registrable Securities and use its reasonable best efforts to cause such 
Registration Statement to remain continuously effective for a period which 
will terminate when all Registrable Securities covered by such Registration 
Statement, as amended from time to time, have been sold or when the 
Registrable Securities may be sold under Rule 144(k) under the 1933 Act;

               (b)  prepare and file with the SEC such amendments and 
post-effective amendments to the Registration Statement and the Prospectus 
and supplements to the Prospectus as may be necessary to keep such 
Registration Statement effective for the period specified in 
Subsection 5.2(a) and to comply with the provisions 


                                - 7 -


of the 1933 Act and the 1934 Act with respect to the distribution of all 
Registrable Securities; provided, however, that with respect to 
Subsections 5.2(a) and 5.2(b), before filing a Registration Statement or 
Prospectus or any amendments or supplements thereto, the Company will 
furnish to the Investor copies of all such documents proposed to be filed, 
which documents will be subject to the review and comment of Investor's 
counsel;

               (c)  notify Investor promptly, and confirm such notice in 
writing, (i) when the Prospectus or any supplement or post-effective 
amendment has been filed, and, with respect to the Registration Statement or 
any post-effective amendment, when the same has become effective, (ii) of any 
request by the SEC for amendments or supplements to the Registration 
Statement or Prospectus or for additional information, (iii) of the issuance 
by the SEC of any stop order suspending the effectiveness of the Registration 
Statement or the initiation of any proceedings for that purpose, and (iv) of 
the receipt by the Company of any notification with respect to the suspension 
of the qualification of the Registrable Securities for sale in any 
jurisdiction or the initiation or threatening of any proceeding for such 
purpose;

               (d)  make every reasonable effort to obtain the withdrawal of 
any order suspending the effectiveness of the Registration Statement at the 
earliest possible moment;

               (e)  furnish to the Investor, without charge, at least one 
copy of the Registration Statement and any post-effective amendment thereto, 
including financial statements and schedules, all, upon a Investor's request, 
documents incorporated therein by reference and all exhibits thereto 
(including those incorporated by reference);

               (f)  deliver to the Investor, without charge, as many copies 
of the Prospectus (including each preliminary prospectus) and any amendment 
or supplement thereto as it may reasonably request in order to facilitate the 
disposition of the Registrable Securities;

               (g)  cause all Registrable Securities covered by the 
Registration Statement to be listed on each securities exchange or market on 
which similar securities issued by the Company are then listed, and if the 
securities are not so listed to use its reasonable best efforts promptly to 
cause all such securities to be listed on either the New York Stock Exchange, 
the American Stock Exchange or the Nasdaq National Market;

               (h)  use reasonable best efforts to qualify or register the 
Registrable Securities for sale under (or obtain exemptions from the 
application of) the Blue Sky laws of such jurisdictions as are applicable. 
The Company shall not be required to qualify as a foreign corporation or to 
file a 

                                - 8 -


general consent to service of process in any such jurisdiction where it is 
not presently qualified or where it would be subject to general service of 
process or taxation as a foreign corporation in any jurisdiction where it is 
not now so subject;

               (i)  otherwise use its reasonable best efforts to comply with 
all applicable rules and regulations of the SEC under the 1933 Act and the 
1934 Act and take such other actions as may be reasonably necessary to 
facilitate the registration of the Registrable Securities hereunder and make 
available to its security holders, as soon as reasonably practicable, an 
earnings statement covering the period of at least twelve months beginning 
with the first day of the Company's first full calendar quarter after the 
effective date of the Registration Statement, which earnings statement will 
satisfy the provisions of Section 11(a) of the 1933 Act and Rule 158 
thereunder;

               (j)  notify the Investor, at any time when a Prospectus 
relating thereto is required to be delivered under the 1933 Act, of the 
happening of any event as a result of which the Prospectus included in such 
Registration Statement contains an untrue statement of a material fact or 
omits any fact necessary to make the statements therein not misleading, and, 
at the request of the Investor, the Company will prepare a supplement or 
amendment to such Prospectus so that, as thereafter delivered to the 
purchasers of such Registrable Securities, such Prospectus will not contain 
an untrue statement of a material fact or omit to state any fact necessary to 
make the statements therein not misleading;

               (k)  provide a transfer agent and registrar for all such 
Registrable Securities not later than the effective date of such Registration 
Statement;

               (l)  enter into such customary agreements (including 
underwriting agreements in customary form) and take all such other actions as 
the Investor, or the underwriter(s) or other Person(s) administering the 
offering, if any, reasonably request in order to expedite or facilitate the 
disposition of such Registrable Securities;

               (m)  make available for inspection by the Investor, any 
underwriter or other Person participating in any disposition pursuant to such 
Registration Statement and any attorney, accountant or other agent retained 
by the Investor or underwriter, financial and other records, pertinent 
corporate documents and properties of the Company, and cause the Company's 
officers, directors, employees and independent accountants to supply all 
information reasonably requested by the Investor, underwriter, attorney, 
accountant or agent in connection with such Registration Statement;

               (n)  if any such registration or comparable statement refers 
to the Investor by name or otherwise as the holder of any 


                                - 9 -


securities of the Company and if in its sole and exclusive judgment, the 
Investor is or might be deemed to be an underwriter or a controlling person 
of the Company, the Investor will have the right to require (i) the insertion 
therein of language, in form and substance satisfactory to the Investor and 
presented to the Company in writing, to the effect that the holding by the 
Investor of such securities is not to be construed as a recommendation by the 
Investor of the investment quality of the Company's securities covered 
thereby and that such holding does not imply that Investor will assist in 
meeting any future financial requirements of the Company, or (ii) in the 
event that such reference to the Investor by name or otherwise is not 
required by the 1933 Act or any similar federal statute then in force, the 
deletion of the reference to the Investor;

               (o)  use its best efforts to cause such Registrable Securities 
covered by such Registration Statement to be registered with or approved by 
such other United States governmental agencies or authorities as may be 
necessary to enable the sellers thereof to consummate the disposition of such 
Registrable Securities; provided, however, that the Company shall not be 
required for any such purpose to qualify generally to do business as a 
foreign corporation in any jurisdiction where, but for the requirements of 
this Subsection 5.2(o), it would not be obligated to qualify or to consent to 
general service of process in any such jurisdiction;

               (p)  furnish the Investor with a cold comfort letter from the 
Company's independent public accountants in customary form and covering such 
matters of the type customarily covered by cold comfort letters; and

               (q)  furnish the Investor with opinions of counsel covering 
all such matters customarily covered regarding the registration of the 
Company's securities.

               Investor shall furnish to the Company such information 
regarding the distribution of such securities as the Company may from time to 
time reasonably request in writing.

               If at any time, the Company delivers a certificate in writing 
to the Investor, to the effect that a delay in the sale of Registrable 
Securities by the Investor under the Registration Statement is necessary 
because a sale pursuant to such Registration Statement in its then current 
form would reasonably be expected to constitute a violation of the federal 
securities laws the Investor shall agree not to sell or otherwise transfer 
such Registrable Securities for the period of time specified by the Company 
in its certificate. In no event shall such delay exceed ten (10) business 
days; PROVIDED, HOWEVER, that if, prior to the expiration of such ten (10) 
business day period, the Company delivers a certificate in writing to the 
Investor to the effect that a further delay in such sale beyond such ten (10) 
business day period is necessary because a sale pursuant to such 


                                - 10 -


Registration Statement in its then current form would reasonably be expected 
to constitute a violation of the federal securities laws, the Company may 
refuse to permit the Investor to resell any Registrable Securities pursuant 
to such Registration Statement for an additional period not to exceed 
five (5) business days.

               5.3  REGISTRATION EXPENSES.  All expenses incident to the 
Company's performance of or compliance with this Agreement, including without 
limitation all registration and filing fees, fees with respect to the filings 
required to be made with the National Association of Securities Dealers, 
Inc., fees and expenses of compliance with the securities or blue sky laws, 
printing expenses, messenger, telephone and delivery expenses, fees and 
disbursements of counsel for the Company, fees and disbursements of all 
independent certified public accountants of the Company, fees and expenses 
incurred in connection with the listing of the securities, rating agency fees 
and the fees and expenses of any person, including special experts, retained 
by the Company, will be borne by the Company, regardless of whether the 
Registration Statement becomes effective; provided, however, that the Company 
will not be required to pay discounts or commissions of underwriters, selling 
brokers, dealer managers or similar securities industry professionals 
relating to the distribution of the Registrable Securities or fees or 
disbursements of any counsel to the Investor.

               5.4  RULE 144.  The Company covenants that it will file the 
reports required to be filed by it under the 1933 Act and the 1934 Act and 
the rules and regulations thereunder, and it will take such further action as 
the Investor may reasonably request, all to the extent required to enable 
Investor to sell Registrable Securities without registration under the 1933 
Act in reliance on the exemption provided by Rule 144 or Rule 144A under the 
1933 Act or any successor or similar rules or statues. Upon the request of 
the Investor, the Company will deliver to the Investor a written statement as 
to whether the Company has complied with such information and requirements.

               5.5  SELECTION OF UNDERWRITER.  If the registration is for a 
registered public offering involving an underwriting, the Investor and the 
Company shall enter into an underwriting agreement in customary form with an 
underwriter or underwriters mutually agreed upon by the Investor and the 
Company; provided however, that the Investor will not be required to make any 
representations or warranties to the Company or to the underwriter(s) (other 
than representations and warranties regarding the Investor's intended method 
of distribution) or to undertake any indemnification obligations to the 
Company or the underwriter(s) with respect thereto except as otherwise 
provided in the Agreement.


                                - 11 -


               5.6  INDEMNIFICATION.

               (a)  The Company will indemnify and hold harmless the Investor 
and each of its officers, directors and partners, and each person controlling 
such Investor, with respect to which such registration, qualification or 
compliance has been effected pursuant to this Agreement, and each 
underwriter, if any, and each person who controls any underwriter of the 
Registrable Securities held by or issuable to such Investor, against all 
claims, losses, expenses, damages and liabilities (or actions in respect 
thereto) arising out of or based on any untrue statement (or alleged untrue 
statement) of a material fact contained in any Prospectus, offering circular 
or other document (including any related Registration Statement, notification 
or the like) incident to any such registration, qualification or compliance, 
or based on any omission (or alleged omission) to state therein a material 
fact required to be stated therein or necessary to make the statement therein 
not misleading, or any violation or alleged violation by the Company of the 
1933 Act, the 1934 Act and any state securities law or any rule or regulation 
promulgated under the 1933 Act, the 1934 Act or any state securities law and 
relating to action or inaction required of the Company in connection with any 
such registration, qualification or compliance, and will reimburse such 
Investor, each of its officers, directors and partners, and each person 
controlling such Investor, each such underwriter and each person who controls 
any such underwriter, within a reasonable amount of time after incurred, for 
any reasonable legal and any other expenses incurred by them in connection 
with investigating, defending or settling any such claim, loss, damage, 
liability or action; provided, however, that the indemnity agreement 
contained in this Subsection 5.6(a) shall not apply to amounts paid in 
settlement of any such claim, loss, damage, liability, or action if such 
settlement is effected without the consent of the Company (which consent 
shall not be unreasonably withheld); and provided further, that the Company 
will not be liable in any such case to the extent that any such claim, loss, 
damages or liability arises out of or is based on any untrue statement or 
omission based upon written information furnished to the Company by such 
Investor, controlling person or underwriter specifically for use therein.

               (b)  The Investor will, if Registrable Securities held by or 
issuable to such Investor are included in the securities as to which such 
registration, qualification or compliance is being effected, indemnify and 
hold harmless the Company, each of its directors and officers, each 
underwriter, if any, of the Company's securities covered by such a 
Registration Statement, and each person who controls the Company within the 
meaning of the 1933 Act, against all claims, losses, expenses, damages and 
liabilities (or actions in respect thereof) arising out of or based on any 
untrue statement (or alleged untrue statement) of a material fact contained 
in any such Registration Statement, Prospectus, offering circular or other 
document, or any omission 


                                - 12 -


(or alleged omission) to state therein a material fact required to be stated 
therein or necessary to make the statement therein not misleading, and will 
reimburse the Company, such director, officers, partners, persons or 
underwriters for any reasonable legal or any other expenses incurred in 
connection with investigating, defending or settling any such claim, loss, 
damages, liability or action, in each case to the extent, but only to the 
extent, that such untrue statement (or alleged untrue statement) or omission 
(or alleged omission) is made in such Registration Statement, Prospectus, 
offering circular or other document in reliance upon and in conformity with 
written information furnished to the Company by the Investor specifically for 
use therein; provided, however, that the indemnity agreement contained in 
this Subsection 5.6(b) shall not apply to amounts paid in settlement of any 
such claim, loss, damage, liability or action if such settlement is effected 
without the consent of the Investor (which consent shall not be unreasonably 
withheld); and provided further, that the total amount for which the Investor 
shall be liable under this Subsection 5.6(b) shall not in any event exceed 
the aggregate proceeds received by the Investor from the sale of Registrable 
Securities held by such Investor in such registration.

               (c)  Each party entitled to indemnification under this 
Subsection 5.6 (the "Indemnified Party") shall give notice to the party 
required to provide indemnification (the "Indemnifying Party") promptly after 
such Indemnified Party has actual knowledge of any claim as to which 
indemnity may be sought, and shall permit the Indemnifying Party to assume 
the defense of any such claim or any litigation resulting therefrom; provided 
that counsel for the Indemnifying Party, who shall conduct the defense of 
such claim or litigation, shall be approved by the Indemnified Party (whose 
approval shall not be unreasonably withheld), and the Indemnified Party may 
participate in such defense at such party's expense; and provided further, 
that the failure of any Indemnified Party to give notice as provided herein 
shall not relieve the Indemnifying party of its obligations hereunder, unless 
such failure resulted in prejudice to the Indemnifying Party; and provided 
further, that an Indemnified Party shall have the right to retain separate 
counsel, with the fees and expenses to be paid by the Indemnifying Party, if 
representation of such Indemnified Party by the counsel retained by the 
Indemnifying Party would be inappropriate due to actual or potential 
differing interests between such Indemnified Party and any other party 
represented by such counsel in such proceeding. No Indemnifying Party, in the 
defense of any such claim or litigation, shall, except with the consent of 
each Indemnified Party, consent to entry of any judgment or enter into any 
settlement which does not include as an unconditional term thereof the giving 
by the claimant or plaintiff to such Indemnified Party of a release from all 
liability in respect to such claim or litigation.


                                - 13 -


               (d)  The obligations of the Company and Investor under this 
Subsection 5.6 shall survive the completion of any offering of Registrable 
Securities in a Registration Statement under Section 5, and otherwise and 
will survive the transfer of the Registrable Securities.

               6.   MISCELLANEOUS.

               6.1  SUCCESSORS AND ASSIGNS.  The terms and conditions of this 
Agreement shall inure to the benefit of and be binding upon the respective 
permitted successors and assigns of the parties. Nothing in this Agreement, 
express or implied, is intended to confer upon any party other than the 
parties hereto or their respective successors and assigns any rights, 
remedies, obligations, or liabilities under or by reason of this Agreement, 
except as expressly provided in this Agreement.

               6.2  GOVERNING LAW.  This Agreement shall be governed by and 
construed under the laws of the State of California (irrespective of its 
choice of law principles).

               6.3  COUNTERPARTS.  This Agreement may be executed in two or 
more counterparts, each of which shall be deemed an original, but all of 
which together shall constitute one and the same instrument.

               6.4  TITLES AND SUBTITLES.  The titles and subtitles used in 
this Agreement are used for convenience only and are not to be considered in 
construing or interpreting this Agreement.

               6.5  NOTICES.  Unless otherwise provided, any notice required 
or permitted under this Agreement shall be given in writing and shall be 
deemed effectively given upon personal delivery to the party to be notified, 
or if sent by telex or telecopier, upon receipt of the correct answerback, or 
upon deposit with the United States Post Office, by registered or certified 
mail, or upon deposit with an overnight air courier, in each case postage 
prepaid and addressed to the party to be notified at the address as follows, 
or at such other address as such party may designate by ten days' advance 
written notice to the other party:

                      If to the Company:

                      Vical Incorporated
                      9373 Towne Centre Drive
                      Suite 100
                      San Diego, CA 92121
                      Attn: Secretary
                      Fax:  (619) 646-1150
                      Phone:  (619) 453-9900


                                - 14 -


                           with a copy to:

                      Pillsbury Madison & Sutro LLP
                      P.O. Box 7880
                      San Francisco, CA 94104
                      Attn:  Thomas E. Sparks, Jr.
                      Fax:  (415) 983-1200
                      Phone:  (415) 983-1000

                      If to the Investor:

                      Pfizer Inc
                      Groton Plant and Research Center
                      Eastern Point Road
                      Groton, CT 06340-5146
                      Attn: Mark DellaPorta
                      Fax:  (860) 441-1738
                      Phone:  (860) 441-1991

               6.6  FINDERS' FEE.  Each party represents that it neither is 
nor will be obligated for any finders' fee or commission in connection with 
this transaction. Investor agrees to indemnify and hold harmless the Company 
from any liability for any commission or compensation in the nature of a 
finders' fee (and the costs and expenses of defending against such liability 
or asserted liability) for which the Investor or any of its officers, 
partners, employees or representatives is responsible.

               The Company agrees to indemnify and hold harmless Investor 
from any liability for any commission or compensation in the nature of a 
finders' fee (and the costs and expenses of defending against such liability 
or asserted liability) for which the Company or any of its officers, 
employees or representatives is responsible.

               6.7  EXPENSES.  The Company and the Investor shall pay their 
respective costs and expenses incurred with respect to the negotiation, 
execution, delivery and performance of this Agreement.

               6.8  AMENDMENTS AND WAIVERS.  Any term of this Agreement may 
be amended and the observance of any term of this Agreement may be waived 
(either generally or in a particular instance and either retroactively or 
prospectively), only with the written consent of the Company and the 
Investor. Any amendment or waiver effected in accordance with this paragraph 
shall be binding upon each holder of any securities purchased under this 
Agreement at the time outstanding, each future holder of all such securities, 
and the Company.

               6.9  SEVERABILITY.  If one or more provisions of this 
Agreement are held to be unenforceable under applicable law, such provision 
shall be excluded from this Agreement and the balance of this Agreement shall 
be interpreted as if such 


                                - 15 -


provision were so excluded and shall be enforceable in accordance with its 
terms.

               6.10  ENTIRE AGREEMENT.  This Agreement constitutes the entire 
agreement between the parties with respect to the subject matter hereof and 
supersedes all prior agreements and understandings, both oral and written, 
between the parties with respect to the subject matter hereof. No 
representation, inducement, promise, understanding, condition or warranty not 
set forth herein has been made or relied upon by either party hereto. Neither 
this Agreement nor any provision hereof is intended to confer upon any Person 
other than the parties hereto any rights or remedies hereunder.

               6.11  OTHER AGREEMENTS.  The Company will not enter into any 
other agreement with respect to its securities which violates the rights 
granted to the Investor in this Agreement.

               IN WITNESS WHEREOF, the parties have executed this Agreement 
as of the date first above written.

                                        VICAL INCORPORATED

                                        By /s/ ALAIN B. SCHREIBER            
                                           ----------------------------------
                                               Alain B. Schreiber, M.D.

                                        Title  President & C.E.O.
                                               ------------------------------


                                        PFIZER INC

                                        By /s/ GEORGE A. MILNE               
                                           ----------------------------------
                                               George A. Milne, Ph.D.

                                        Title  President, Central Research
                                               ------------------------------



                                    - 16 -