<PAGE>

                                                                   EXHIBIT 10.22


[CONFIDENTIAL TREATMENT REQUESTED. CONFIDENTIAL PORTIONS OF THIS AGREEMENT HAVE
BEEN REDACTED AND HAVE BEEN SEPARATELY FILED WITH THE COMMISSION.]






                                LICENSE AGREEMENT
                                     BETWEEN
                             VASCULAR GENETICS INC.
                                       AND
                               VICAL INCORPORATED

                                FEBRUARY 24, 2000


<PAGE>

                                TABLE OF CONTENTS

<TABLE>

<S>                                                                                                     <C>
1.    BACKGROUND.........................................................................................1
2.    DEFINITIONS........................................................................................2
3.    LICENSE GRANT......................................................................................6
4.    PAYMENTS AND ROYALTIES.............................................................................7
5.    TECHNOLOGY TRANSFER................................................................................8
6.    PRODUCT DEVELOPMENT................................................................................9
7.    CONFIDENTIALITY...................................................................................10
8.    PATENT PROSECUTION AND LITIGATION.................................................................12
9.    STATEMENTS AND REMITTANCES........................................................................13
10.   TERM AND TERMINATION..............................................................................15
11.   WARRANTIES AND REPRESENTATIONS....................................................................16
12.   INDEMNIFICATION...................................................................................17
13.   ***.................................................................................................
14.   FORCE MAJEURE.....................................................................................19
15.   DISPUTE RESOLUTION................................................................................20
16.   ENTIRE AGREEMENT..................................................................................21
17.   NOTICES...........................................................................................21
18.   ASSIGNMENT AND CHANGE OF CONTROL..................................................................22
19.   COUNTERPARTS......................................................................................22
20.   WAIVER............................................................................................23
21.   INDEPENDENT RELATIONSHIP..........................................................................23
22.   FURTHER ACTIONS...................................................................................23
</TABLE>


                                        i
<PAGE>

                                LICENSE AGREEMENT

         This Agreement ("Agreement") dated as of the 24th day of February 2000
("Effective Date") is entered into by Vascular Genetics Inc. ("VGI"), a Delaware
corporation, having a place of business at Suite 201, 4364 S. Alston Avenue,
Durham, North Carolina 27713, and Vical Incorporated, a Delaware corporation,
having a place of business at 9373 Towne Center Drive, San Diego, California
92121 ("VICAL").

1.       BACKGROUND.

1.1      VGI has an exclusive license from Human Genome Sciences, Inc. ("HGS")
         for the use of the gene Vascular Endothelial Growth Factor-2 ("VEGF-2")
         in the gene therapy treatment of vascular diseases.

1.2      VICAL is in possession of certain gene therapy delivery methods, and is
         willing to grant a license to VGI for the use of those methods in
         conjunction with VEGF-2.

1.3      Therefore to facilitate this transaction, VGI, VICAL and HGS have
         agreed in an Investment Agreement dated of same date herewith (the
         "Investment Agreement") to undertake a series of transactions in which
         (1) VGI will receive a license from VICAL for the use of VICAL's
         current and future gene therapy delivery methods in conjunction with
         VEGF-2; (2) HGS will receive a license from VICAL for the use of
         VICAL's technology with certain genes; (3) VICAL will receive a license
         from HGS for the use of certain genes as gene therapy products; (4)
         VICAL will receive an equity interest in VGI, which VGI will have
         certain rights to redeem as set forth in the Investment Agreement; and
         (5) HGS will receive additional equity in VGI and will have returned to
         it by VGI rights to certain genes licensed to VGI by HGS.

1.4      To effect this series of transactions pursuant to the terms and
         conditions of the Investment Agreement, this Agreement is being
         simultaneously executed with (1) a license agreement between VICAL and
         HGS; and (2) a second amendment to the license agreement between HGS
         and VGI; and (3) certain other agreements, all as set forth in the
         Investment Agreement.


                                        1
<PAGE>

2.       DEFINITIONS.

2.1      "AFFILIATE" shall mean any individual or entity directly or indirectly
         controlling, controlled by or under common control with, the specified
         individual or entity. For purposes of this Agreement, the direct or
         indirect ownership of fifty percent (50%) or more of the outstanding
         voting securities of an entity, or the right to receive fifty (50%) or
         more of the profits or earnings of an entity shall be deemed to
         constitute control. Such other relationship as in fact gives such
         individual or entity the power or ability to control the management,
         business and affairs of an entity shall also constitute control.

2.2      "CONFIDENTIAL INFORMATION" shall mean, with respect to a party, all
         information (and all tangible and intangible embodiments thereof),
         which is owned or controlled by such party, is disclosed by such party
         to the other party pursuant to this Agreement, and (if disclosed in
         writing or other tangible medium) is marked or identified as
         confidential at the time of disclosure to the receiving party or (if
         otherwise disclosed) is identified as confidential at the time of
         disclosure to the receiving party and described as such in writing
         within thirty (30) days after such disclosure. The Financial Details
         (as hereinafter defined) shall be deemed to be marked as confidential
         without further action on the part of either party. Notwithstanding the
         foregoing, CONFIDENTIAL INFORMATION of a party shall not include
         information which, and only to the extent, the receiving party can
         establish by written documentation (a) has been publicly known prior to
         disclosure of such information by the disclosing party to the receiving
         party, (b) has become publicly known, without fault on the part of the
         receiving party, subsequent to disclosure of such information by the
         disclosing party to the receiving party, (c) has been received by the
         receiving party at any time from a source, other than the disclosing
         party, rightfully having possession of and the right to disclose such
         information free of confidentiality obligations, (d) has been otherwise
         known by the receiving party free of confidentiality obligations prior
         to disclosure of such information by the disclosing party to the
         receiving party, or (e) has been independently developed by employees
         or others on behalf of the receiving party without access to or use of
         such information disclosed by the disclosing party to the receiving
         party.


                                        2
<PAGE>

2.3      "CYTOFECTIN DELIVERY TECHNOLOGY" shall mean all patentable or
         unpatentable inventions, discoveries, technology and information of any
         type whatsoever, including without limitation compositions, methods,
         processes, confidential information, technical information, knowledge,
         experience and know-how, regarding the use of cytofectins in the
         delivery of genes into a patient for the treatment or prevention of one
         or more diseases or conditions; in each case which is owned by or
         licensed to VICAL on the Effective Date or during the term of this
         Agreement, all to the extent and only to the extent that VICAL now has
         or hereafter will have the right to grant licenses, immunities or other
         rights thereunder.

2.4      "DIRECT INJECTION TECHNOLOGY" shall mean all patentable or unpatentable
         inventions, discoveries, technology and information of any type
         whatsoever, including without limitation compositions, methods,
         processes, confidential information, technical information, knowledge,
         experience and know-how, regarding the direct injection of genes
         (including plasmid DNA-based delivery technology) into a patient to
         cause the IN VIVO expression of a desired protein, thereby effecting
         delivery of such protein to a patient for the treatment or prevention
         of one or more diseases or conditions; in each case which is owned by
         or licensed to VICAL on the Effective Date or during the term of this
         Agreement, all to the extent and only to the extent that VICAL now has
         or will have during the term of this Agreement the right to grant
         licenses, immunities or other rights thereunder.

2.5      "DNA PROCESS TECHNOLOGY" shall mean all patentable or unpatentable
         inventions, discoveries, technology and information of any type
         whatsoever, including without limitation compositions, methods,
         processes, confidential information, technical information, knowledge,
         experience and know-how regarding technologies related to the
         manufacture and processing of plasmid DNA for human use; in each case,
         which is owned by or licensed to VICAL on the Effective Date or during
         the term of this Agreement, all to the extent and only to the extent
         that VICAL now has or will have during the term of this Agreement the
         right to grant licenses, immunities or other rights thereunder.


                                        3
<PAGE>

2.6      "FIELD" shall mean the intervention, treatment and/or prevention of a
         disease or disorder in humans by GENE THERAPY.

2.7      "GENE THERAPY" shall mean the treatment or prevention of a disease, or
         remedying a gene deficiency of humans by genetic modification of
         somatic cells (IN VIVO or EX VIVO) with DNA whereby an active
         transcription process results in the expression of a protein or
         oligo(poly)nucleotide encoded by said DNA in a human.

2.8      "IND" shall mean an Investigational New Drug application filed with the
         Food and Drug Administration in the United States, or any similar
         filing with any foreign regulatory authority, to commence human
         clinical testing of a PRODUCT in any country.

2.9      "LICENSED INTELLECTUAL PROPERTY" shall mean VICAL's rights in the VICAL
         PATENTS and VICAL KNOW-HOW.

2.10     "LICENSED PRODUCT(S)" means a PRODUCT for use in the FIELD, one of
         whose active components is the gene, a portion of the gene, or a
         derivative of the gene, Vascular Endothelial Growth Factor-2
         ("VEGF-2"), as described and disclosed in U.S. Patent Nos. 5,935,820
         and 5,932,540.

2.11     "NET SALES" shall mean, with respect to a LICENSED PRODUCT, the gross
         sales price invoiced by the seller (calculated on a LICENSED PRODUCT by
         LICENSED PRODUCT basis) to THIRD PARTIES that are not (sub)licensees
         (except as set forth below), less normal and customary deductions
         actually paid or accrued by the seller for (i) normal and customary
         trade, cash and quality credits, discounts, refunds or government
         rebates; (ii) credits for claims, allowances or returns; retroactive
         price reductions; chargebacks or the like; and (iii) sales taxes,
         duties and other governmental charges (including value added tax), but
         excluding what is commonly known as income taxes. NET SALES shall not
         include sales among the seller, its (sub)licensees and their respective
         AFFILIATES for resale, provided that NET SALES shall include the
         amounts invoiced by the seller and its AFFILIATES to THIRD PARTIES on
         the resale of such LICENSED PRODUCT. Sales between or among a party,
         its (sub)licensees and their


                                        4
<PAGE>

         respective AFFILIATES shall be included within NET SALES only if such
         purchaser is an end-user of such LICENSED PRODUCT.

2.12     "PRODUCT" shall mean any product or part thereof, the manufacture, use
         or sale of which is covered in whole or in part by a VALID CLAIM.

2.13     "SPC" shall mean a right based upon an underlying patent such as a
         Supplementary Protection Certificate.

2.14     "THIRD PARTY" shall mean any party other than VICAL or VGI or an
         AFFILIATE of VICAL or VGI.

2.15     "VALID CLAIM" shall mean either (a) a claim of an issued and unexpired
         patent included within the VICAL PATENTS, which has not been held
         unenforceable, unpatentable or invalid by a court or other governmental
         agency of competent jurisdiction, and which has not been admitted to be
         invalid or unenforceable through reissue, disclaimer or otherwise, or
         (b) a claim in a hypothetical issued patent corresponding to a pending
         claim in a patent application within the VICAL PATENTS, provided that
         if such pending claim has not issued as a claim of an issued patent
         within the VICAL PATENTS, within six (6) years after the filing date
         from which such patent application takes priority, such pending claim
         shall not be a VALID CLAIM for purposes of this Agreement. In the event
         that a claim of an issued patent within the VICAL PATENTS is held by a
         court or other governmental agency of competent jurisdiction to be
         unenforceable, unpatentable or invalid, and such holding is reversed on
         appeal by a higher court or agency of competition jurisdiction, such
         claim shall be reinstated as a VALID CLAIM hereunder.

2.16     "VICAL IMPROVEMENTS" shall mean all patentable or unpatentable
         inventions, discoveries or other technology regarding VICAL TECHNOLOGY,
         but expressly excluding a formulation or combination of the VEGF-2 gene
         and the delivery vehicle therefor, made or conceived by VGI solely or
         jointly with others during the term of this Agreement, and which
         resulted from the use of VICAL TECHNOLOGY.


                                        5
<PAGE>

2.17     "VICAL KNOW-HOW" shall mean collectively, all inventions, discoveries,
         data, information, methods, techniques, technology and other results
         regarding VICAL TECHNOLOGY, whether or not patentable, which during the
         term of this Agreement are owned by VICAL or to which VICAL otherwise
         has the right to grant licenses, and which are not generally known. All
         VICAL KNOW-HOW shall be CONFIDENTIAL INFORMATION of VICAL.

2.18     "VICAL LICENSED INTELLECTUAL PROPERTY" shall mean VICAL's rights in the
         VICAL PATENTS and VICAL KNOW-HOW.

2.19     "VICAL PATENT(S)" shall mean, collectively, (a) all patent applications
         filed in any country before or after the Effective Date; (b) all
         patents that have issued or in the future issue from any of the
         foregoing patent applications, including without limitation, utility
         and design patents and certificates of invention, further including but
         not limited to those patents listed in Appendix A; and (c) all
         continuations, continuations-in-part, divisional, additions, reissues,
         renewals, re-examinations or extensions, or SPCs to any such patents
         and patent applications; in each case which during the term of this
         Agreement are or become owned by VICAL or to which VICAL otherwise has,
         now or in the future, the right to grant licenses and which claim in
         whole or in part VICAL TECHNOLOGY or the use thereof in the FIELD.

2.20     "VICAL TECHNOLOGY" shall mean CYTOFECTIN DELIVERY TECHNOLOGY, DIRECT
         INJECTION TECHNOLOGY and DNA PROCESS TECHNOLOGY.

3.       LICENSE GRANT.

3.1      Subject to the terms and conditions of this Agreement, VICAL grants to
         VGI an exclusive worldwide license (with the right to grant
         sublicenses) under VICAL LICENSED INTELLECTUAL PROPERTY to research,
         develop, make, have made, use, import, export, offer to sell and sell
         LICENSED PRODUCTS in the FIELD.

3.2      Notwithstanding anything to the contrary herein, VICAL shall own all
         right, title and interest in and to the VICAL IMPROVEMENTS and all
         intellectual property rights


                                        6
<PAGE>

         therein and thereto. VGI hereby irrevocably assigns, transfers and
         conveys to VICAL all right, title and interest in and to the VICAL
         IMPROVEMENTS and all intellectual property rights therein and thereto.
         VGI shall take, and shall cause its AFFILIATES to take any and all
         actions and execute and deliver (or cause to be executed or delivered)
         any and all documents reasonably requested by VICAL, at VICAL's
         expense, in order to effect the foregoing assignment.

3.3      VICAL hereby grants VGI a non-exclusive, royalty-free, perpetual,
         worldwide, sublicensable license to VICAL IMPROVEMENTS and the claims
         of any VICAL PATENT covering such VICAL IMPROVEMENTS, but only to the
         extent that such claims cover VICAL IMPROVEMENTS.

3.4      No rights, other than those expressly set forth in this Agreement, are
         granted to VGI hereunder, and no additional rights shall be granted to
         VGI by implication, estoppel or otherwise.

4.       PAYMENTS AND ROYALTIES.

4.1      On the Effective Date, VGI will issue to VICAL shares of VGI's Series B
         Preferred Stock in such amount, and subject to the terms, as described
         in the Investment Agreement.

4.2      Subject to Section 4.3, for each LICENSED PRODUCT, VGI shall pay to
         VICAL a royalty of *** of NET SALES of the LICENSED PRODUCT sold by
         VGI, its (sub)licensees and their respective AFFILIATES.

4.3      VGI acknowledges that the LICENSED INTELLECTUAL PROPERTY hereunder is a
         mix of various types of intellectual property, including patent rights
         and know-how. Accordingly, even in the event one or more VICAL PATENTS
         or other LICENSED INTELLECTUAL PROPERTY is declared void or not
         enforceable, or otherwise expires

         ____________

*** Confidential material redacted and separately filed with the Commission.


                                        7
<PAGE>

         VGI shall continue to have royalty obligations under the terms of this
         Agreement; provided, however, in such case, and except as otherwise set
         forth below in this Section 4.3, such royalty obligations will cease in
         the event all information transferred hereunder is finally determined
         by a court of competent jurisdiction after exhaustion of all appeals to
         be dedicated to the public domain. Notwithstanding the foregoing
         provisions, however, all royalty obligations under Section 4.2, with
         respect to a LICENSED PRODUCT, shall terminate on a country-by-country
         basis and on a LICENSED PRODUCT by LICENSED PRODUCT basis on the later
         of (i) *** after first country-wide launch of such LICENSED PRODUCT in
         such country or (ii) expiration of the last to expire VICAL PATENT
         licensed to VGI under this Agreement which covers the making, having
         made, importing, exporting, offering to sell or using or selling of
         such LICENSED PRODUCT in such country.

4.4      The manner in which statements and remittances of royalty and other
         payments are handled is as set forth in Article 9 hereof.

4.5      All payments to be made hereunder shall be by wire transfer of
         immediately available funds to an account designated by VICAL.

5.       TECHNOLOGY TRANSFER

5.1      To assist VGI in the utilization of VICAL TECHNOLOGY, VICAL scientists
         will meet with VGI scientists to discuss the application of VICAL
         TECHNOLOGY to VEGF-2 and will provide to VGI any know-how or
         proprietary materials necessary for VGI to use the VICAL TECHNOLOGY
         with respect to VEGF-2 in accordance with the license granted under
         Section 3.1.

         ____________

*** Confidential material redacted and separately filed with the Commission.

                                        8
<PAGE>

6.       PRODUCT DEVELOPMENT

6.1      VGI shall use its commercially reasonable efforts to actively research,
         develop, obtain regulatory approvals and commercialize in at least one
         major market (U.S., Japan or the European Community) at least one
         LICENSED PRODUCT for at least one indication.

6.2      If the diligence requirements set forth in Paragraph 6.1 are not met,
         Vical shall have the right to terminate this Agreement pursuant to
         Paragraph 10.2. Notwithstanding the foregoing if VGI is pursuing
         development and commercialization of a product (a "NON-VICAL PRODUCT")
         for use in the FIELD, one of whose active components is VEGF-2, a
         portion of VEGF-2, or a derivative of VEGF-2 and which was not derived
         from VICAL TECHNOLOGY, VGI shall have the option, exercisable by
         written notice to VICAL within thirty (30) days after the date of such
         termination by VICAL, at its sole discretion to retain the relevant
         VICAL licenses under this Agreement for any or all indications where
         the NON-VICAL PRODUCT is applied, provided that VGI pays to VICAL the
         royalties set forth in Paragraph 4.2 on the NET SALES of such NON-VICAL
         PRODUCT for the indication or indications intended to be retained by
         VGI and delivers all reports described in this Agreement, regarding
         such NON-VICAL PRODUCT in the desired indication to the same extent it
         would if such NON-VICAL PRODUCT were a LICENSED PRODUCT.

6.3      During the term of this Agreement and for a period of five (5) years
         thereafter, VGI shall keep complete and accurate records of its
         activities conducted under this Agreement regarding the development and
         commercialization of LICENSED PRODUCTS and the results thereof. Within
         twenty (20) days after the end of each May and September during the
         term of this Agreement, VGI shall prepare and provide VICAL with a
         reasonably detailed written report of such activities and results,
         through such date.


                                     9
<PAGE>

7.       CONFIDENTIALITY

7.1      During the term of this Agreement and for a period of *** following the
         expiration or earlier termination hereof, each party shall maintain in
         confidence the CONFIDENTIAL INFORMATION of the other party, and shall
         not disclose, use or grant the use of the CONFIDENTIAL INFORMATION of
         the other party except on a need-to-know basis to such party's
         AFFILIATES, directors, officers, employees, agents, independent
         contractors and such party's THIRD PARTY licensors of intellectual
         property rights (sub)licensed hereunder, and such party's consultants,
         to the extent such disclosure is reasonably necessary in connection
         with such party's activities as expressly authorized by this Agreement
         or the Investment Agreement. To the extent that disclosure to any
         person is authorized by this Agreement, prior to disclosure, a party
         shall obtain written agreement of such person to hold in confidence and
         not disclose, use or grant the use of the CONFIDENTIAL INFORMATION of
         the other party except as expressly permitted under this Agreement.
         Each party shall notify the other party promptly upon discovery of any
         unauthorized use or disclosure of the other party's CONFIDENTIAL
         INFORMATION. Upon the expiration or earlier termination of this
         Agreement, each party shall return to the other party all tangible
         items regarding the CONFIDENTIAL INFORMATION of the other party and all
         copies thereof; PROVIDED, HOWEVER, that each party shall have the right
         to retain one (1) copy for its legal files for the sole purpose of
         determining its obligations hereunder.

7.2      No public announcement or public disclosure concerning (i) the
         existence or terms of this Agreement or the Investment Agreement,
         including without limitation, the number of shares of Series B
         Preferred Shares or Common Stock which is issuable upon conversion
         thereof, the number of Additional Common Shares or the percentage any
         of such represent of the outstanding equity of VGI or the terms of the
         royalties set forth in this Agreement (collectively, the "Financial
         Details") or (ii) exercise by one party of rights

         ____________
*** Confidential material redacted and separately filed with the Commission.


                                    10
<PAGE>

         and options granted under this Agreement or the Investment Agreement,
         shall be made, either directly or indirectly, by any party to this
         Agreement without prior written notice and, except as may be legally
         required, or as may be legally required for a public offering of
         securities, or as may be required for recording purposes, without first
         obtaining the approval of the other party and agreement upon the nature
         and text of such announcement, such agreement and/or approval not to be
         unreasonably withheld. In complying with any legal requirement for
         public announcement or public disclosure, the party having the
         obligation to so announce or disclose shall use reasonable efforts to
         summarize or redact information containing the Financial Details as
         reasonably requested by the other party. Except as otherwise required
         by law, the party desiring to make any such public announcement or
         public disclosure shall inform the other party of the proposed
         announcement or disclosure at least five (5) business days prior to
         public release, and shall provide the other party with a written copy
         thereof, in order to allow such other party to comment upon such
         announcement or disclosure. This Section 7.2 shall not apply to any
         information in a public announcement or public disclosure that is
         information essentially identical to that contained in a previous
         public announcement or public disclosure agreed to pursuant to this
         Section 7.2.

7.3      The confidentiality obligations under Section 7.1 shall not apply to
         the extent that a party is required to disclose information by
         applicable law, regulation or order of a governmental agency or a court
         of competent jurisdiction; PROVIDED, HOWEVER, that (a) to the extent
         commercially practicable, such party shall provide written notice
         thereof to the other party and consult with the other party prior to
         such disclosure with respect thereto, (b) shall provide the other party
         sufficient opportunity to object to any such disclosure or to request
         confidential treatment thereof, and provide reasonable assistance as
         requested in connection therewith and (c) in the event that the
         disclosure is a public disclosure or public announcement, the
         disclosing party shall also comply with Section 7.2.

7.4      Each party hereto acknowledges that the remedy at law for breach by any
         party of its obligations under this Section 7 is inadequate and that
         each party shall be entitled to equitable remedies, including
         injunctive relief, in the event of a breach by the other party.


                                       11
<PAGE>

7.5      The provisions of this Section 7 are in addition to and do not
         supercede and are not superceded by similar provisions in any other
         agreements.

8.       PATENT PROSECUTION AND LITIGATION.

8.1      All right, title and interest to the VICAL TECHNOLOGY and all patent
         rights and other intellectual property rights therein shall belong
         solely to VICAL. VICAL shall have the sole right and responsibility for
         the filing, prosecution and maintenance of patents and patent
         applications directed thereto.

8.2      In the event that VGI or VICAL becomes aware of actual or threatened
         infringement of a VICAL PATENT that claims a LICENSED PRODUCT or the
         use thereof, that party shall promptly notify the other party in
         writing. VICAL shall have the first right but not the obligation to
         bring, at its own expense, an infringement action against any THIRD
         PARTY and to use VGI's name in connection therewith. If VICAL does not
         commence a particular infringement action within ninety (90) days, VGI,
         after notifying VICAL in writing, shall be entitled to bring such
         infringement action, in its own name and/or in the name of VICAL, at
         its own expense to the extent that such party is licensed thereunder.
         The foregoing notwithstanding, in the event that an alleged infringer
         certifies pursuant to 21 U.S.C. Section 355(b)(2)(A)(iv) against an
         issued VICAL PATENT covering a LICENSED PRODUCT, as between VICAL AND
         VGI, the party receiving notice of such certification shall immediately
         notify the other party of such certification, and if fourteen (14) days
         prior to expiration of the forty five (45) day period set forth in 21
         U.S.C. Section 355(c)(3)(C), VICAL fails to commence an infringement
         action, the party receiving notice, in its sole discretion, at its own
         expense and to the extent that it is licensed under the patent, shall
         be entitled to bring such infringement action in its own name and/or in
         the name of the patent owner. The party conducting an action under this
         Section 8.2 shall have full control over its conduct, including
         settlement thereof provided such settlement shall not be made without
         the prior written consent of the other party if it would adversely
         affect the patent rights of such party licensed hereunder. VICAL and
         VGI shall reasonably assist one another and cooperate in any such
         litigation at the other's request.


                                    12
<PAGE>

         The party conducting the litigation shall reimburse the other party
         for its reasonable and actual out-of-pocket expenses incurred at the
         request of the party conducting the litigation for assisting in the
         litigation, which reimbursement shall be made within thirty (30)
         days of receipt by the party conducting the litigation of itemized
         invoices from the assisting party documenting such expenses.

8.3      Any recovery made by a party as the result of an action for patent
         infringement it has conducted under Section 8.2 shall be distributed as
         follows:

         (a)      The party conducting the action shall recover its actual out
                  -of-pocket expenses, and then shall reimburse the other party
                  for any unreimbursed actual and out-of-pocket expenses.

         (b)      To the extent that the recovery exceeds the total of item (a),
                  the excess shall be kept by the party conducting the action,
                  provided, however, that to the extent that the recovery is
                  based on an award of lost sales/profits, VICAL shall receive a
                  proportion of the excess recovery corresponding to the royalty
                  percentage it would have otherwise been due on those lost
                  sales/profits and VGI shall receive the proportion of the
                  excess recovery corresponding to the lost sales/profits.

8.4      The parties shall periodically keep one another reasonably informed of
         the status of their respective activities regarding any such litigation
         or settlement thereof.

9.       STATEMENTS AND REMITTANCES.

9.1      VGI shall keep and require its AFFILIATES and (sub)licensees to keep
         complete and accurate records of all sales and calculations for NET
         SALES of LICENSED PRODUCTS. Each party shall have the right, at its
         expense, through an independent certified public accounting firm of
         nationally recognized standing reasonably acceptable to the other
         party, to examine pertinent financial records during regular business
         hours


                                 13
<PAGE>

         upon advance written notice during the life of this Agreement and for
         *** after its termination for the purpose of verifying and reporting to
         VICAL as to the computation of the payments made hereunder during the
         preceding *** prior to the date of such examination; provided, however,
         that such examination shall not take place more often than once a year;
         provided further that such accountant shall report only as to the
         accuracy of the royalty statements and payments, including the
         magnitude and source of any discrepancy. VGI, its AFFILIATES and
         (sub)licensees shall be required to maintain such sales and royalty
         calculation records for ***. The accountant shall execute customary
         confidentiality agreements prior to any examination, reasonably
         satisfactory in form and substance to both parties, to maintain in
         confidence all information obtained during the course of any such
         examination, except for disclosure to the parties, as necessary for the
         above purpose.

9.2      Within sixty (60) days after the close of each calendar quarter, VGI
         shall deliver to VICAL a true accounting of amounts owing hereunder
         sold by it and its licensees and distributors during such calendar
         quarter and shall at the same time pay all amounts due.

9.3      All royalties and other payments due under this Agreement shall be
         payable in U.S. dollars.

9.4      Royalties payable on sales in countries other than the United States
         shall be calculated by multiplying the appropriate royalty rate times
         the sales in each currency in which they are made and converting the
         resulting amount into United States dollars, at the rates of exchange
         as reported in THE WALL STREET JOURNAL as published under the caption
         "Currency Trading"), on the last business day in New York, New York of
         each royalty period. If THE WALL STREET JOURNAL ceases to be published,
         then the rate of exchange to be used shall be that reported in such
         other business publication of national circulation in the United States
         as all parties reasonably agree. Such payments shall be without
         deduction of exchange, collection, or other charges. If, due to
         restrictions or prohibitions imposed

         ____________

*** Confidential material redacted and separately filed with the Commission.


                                    14
<PAGE>

         by a national or international authority, payments cannot be made as
         aforesaid, the parties shall consult with a view to finding a prompt
         and acceptable solution, and the parties will deal with such monies as
         the other party may lawfully direct at no additional out-of-pocket
         expense to the party owed the royalty. Notwithstanding the foregoing,
         if royalties cannot be remitted for any reason within six (6) months
         after the end of the calendar quarter during which they are earned,
         then the party owing the royalty shall be obligated to deposit the
         royalties in a bank account in the country of sale in the name of the
         other party. Each party shall deduct any taxes which the party is
         obligated to pay and/or withhold in a country based on royalties due to
         the other based on sales in such country from royalty payments due for
         such country under this Agreement and pay them to the proper
         authorities as required by applicable laws. Each party shall maintain
         official receipts of payment of any such taxes and forward these
         receipts to the other within sixty (60) days.

10.      TERM AND TERMINATION.

10.1     This Agreement shall come into effect as of the Effective Date, and
         unless earlier terminated as provided in this Article 10, shall remain
         in full force and effect in a country-by-country basis until the
         expiration of VGI's royalty obligations for such LICENSED PRODUCT in
         such country.

10.2     A party shall have the right to terminate this Agreement in its
         entirety (a) upon the breach by the other party of such other party's
         obligations to pay any amounts owing hereunder, if such breach is not
         cured within thirty (30) days after receipt of written notice from such
         party thereof, or (b) upon the breach by the other party of such other
         party's obligations (other than to pay any amounts owing) hereunder, if
         such breach is not cured within sixty (60) days after receipt of
         written notice from such party thereof.

10.3     Notwithstanding termination of this Agreement, the rights and
         obligations of the parties under Sections 3.2 and 3.3 and Articles 7,
         9, 10, 11, 12 and 15 shall survive such


                                   15
<PAGE>

         termination, as well as any provision not specified in this
         paragraph which is clearly meant to survive termination of this
         Agreement.

10.4     Termination of the Agreement in accordance with the provisions hereof
         shall not limit remedies that may be otherwise available in law or
         equity.

11.      WARRANTIES AND REPRESENTATIONS.

11.1     Each of VGI and VICAL hereby represents, warrants and covenants to the
         other, as of the date of this Agreement, as follows:

         (a)      it is a corporation duly organized and validity existing under
                  the laws of the state of its incorporation;

         (b)      the execution, delivery and performance of this Agreement by
                  such party has been duly authorized by all requisite corporate
                  action;

         (c)      it has the power and authority to execute and deliver this
                  Agreement and to perform its obligations hereunder, including,
                  without limitation, in the case of VICAL, the right, power and
                  authority to grant the licenses under Article 3;

         (d)      the execution, delivery and performance by such party of this
                  Agreement and its compliance with the terms and provisions
                  hereof to such party's best knowledge does not conflict with
                  or result in a breach of any of the terms and provisions of or
                  constitute a default under (i) a loan agreement, guaranty,
                  financing agreement, agreement affecting a product or other
                  agreement or instrument binding or affecting it or its
                  property; (ii) the provisions of its charter documents or
                  bylaws; or (iii) any order, writ, injunction or decree of any
                  court or governmental authority entered against it or by which
                  any of its property is bound; and

         (e)      this Agreement constitutes such party's legal, valid and
                  binding obligation enforceable against it in accordance with
                  its terms subject, as to enforcement, to bankruptcy,
                  insolvency, reorganization and other laws of general
                  applicability


                                    16
<PAGE>

                  relating to or affecting creditors' rights and to the
                  availability of particular remedies under general equity
                  principles.

11.2     NOTHING IN THIS AGREEMENT SHALL BE CONSTRUED AS A WARRANTY THAT VICAL
         PATENTS ARE VALID OR ENFORCEABLE OR THAT THEIR EXERCISE OR THE EXERCISE
         OF VICAL TECHNOLOGY DOES NOT INFRINGE ANY PATENT RIGHTS OF THIRD
         PARTIES. A HOLDING OF INVALIDITY OR UNENFORCEABILITY OF ANY SUCH
         PATENT, FROM WHICH NO FURTHER APPEAL IS OR CAN BE TAKEN, SHALL NOT
         AFFECT ANY OBLIGATION HEREUNDER, BUT SHALL ONLY ELIMINATE ROYALTIES
         OTHERWISE DUE UNDER SUCH PATENT FROM THE DATE SUCH HOLDING BECOMES
         FINAL.

11.3     EXCEPT AS OTHERWISE EXPRESSLY SET FORTH HEREIN VGI AND VICAL MAKE NO
         REPRESENTATIONS OR EXTEND ANY WARRANTIES OF ANY KIND, EITHER EXPRESS OR
         IMPLIED, INCLUDING, BUT NOT LIMITED TO, WARRANTIES OF MERCHANTABILITY
         OR FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT.

11.4     Each party shall use any materials provided by the other party under
         this Agreement in compliance with all applicable laws and regulations.

12.      INDEMNIFICATION

12.1     VGI shall defend, indemnify and hold harmless VICAL, its AFFILIATES
         licensors of VICAL and each of their respective directors, officers,
         shareholders, agents and employees, from and against any and all
         liability, loss, damages and expenses (including reasonable attorneys'
         fees) as the result of claims, demands, actions or proceedings by any
         THIRD PARTY which are made or instituted against any of them arising
         out of the development, manufacture, possession, distribution, use,
         testing, sale or other disposition of LICENSED PRODUCT by or through
         VGI, its AFFILIATES or any THIRD PARTY granted rights by VGI under this
         Agreement. VGI's obligation to defend, indemnify and hold harmless
         shall include claims, demands, actions or proceedings, whether for
         money


                                   17
<PAGE>

         damages or equitable relief by reason of alleged personal injury
         (including death) to any person or alleged property damage, provided,
         however, the indemnity shall not extend to any claims against an
         indemnified party which result from the gross negligence or willful
         misconduct of an indemnified party. VGI shall have the exclusive right
         to control the defense of any action which is to be indemnified in
         whole by VGI hereunder, including the right to select counsel
         reasonably acceptable to VICAL to defend VICAL and the indemnified
         parties hereunder and to settle any claim, demand, action or
         proceeding, provided that, without the prior written consent of VICAL
         (which shall not be unreasonably withheld or delayed), VGI shall not
         agree to settle any claim, demand, action or proceeding against VICAL
         to the extent such claim has a material adverse effect on VICAL. The
         provisions of this paragraph shall survive and remain in full force and
         effect after any termination, expiration or cancellation of this
         Agreement and VGI's obligation hereunder shall apply whether or not
         such claims are rightfully brought. VGI shall require each
         (sub)licensee hereunder to agree to indemnify VICAL in a manner
         consistent with this Section 12.1.

12.2     If VICAL intends to claim indemnification under this Article 12, VICAL
         shall promptly notify VGI of any claim, demand, action or proceeding
         for which VICAL intends to claim such indemnification, and VGI, after
         it determines that indemnification is required of it, shall assume the
         defense thereof with counsel selected by VGI and reasonably acceptable
         to the other party; provided, however, that VICAL shall have the right
         to retain its own counsel, with the fees and expenses to be paid by VGI
         if VGI does not assume the defense; or, if representation of VICAL by
         the counsel retained by VGI would be inappropriate due to actual or
         potential conflicts of interest between VICAL and any other party
         represented by such counsel in such proceedings. The indemnity
         agreement in this Article 12 shall not apply to amounts paid in
         settlement of any claim, demand, action or proceeding if such
         settlement is effected without the consent of VGI, which consent shall
         not be unreasonably withheld or delayed. The failure to deliver notice
         to VGI within a reasonable time after the commencement of any such
         action, if prejudicial to its ability to defend such action, shall
         relieve VGI of any liability to VICAL under this Article 12, but
         failure to deliver notice to VGI will not relieve it of any liability
         that it may have to VICAL otherwise than under this Article 12. VICAL
         under this


                                   18
<PAGE>

         Article 12, its employees and agents, shall reasonably cooperate
         with VGI and its legal representatives in the investigations of any
         claim, demand, action or proceeding covered by this indemnification.
         In the event that each party claims indemnity from the other and one
         party is finally held liable to indemnify the other, VGI shall
         additionally be liable to pay the reasonable legal costs and
         attorneys' fees incurred by VICAL in establishing its claim for
         indemnity.

13.      ***

13.1     ***

14.      FORCE MAJEURE

14.1     If the performance by a party of any obligation under this Agreement
         (other than an obligation for a payment of money), is prevented,
         restricted, interfered with or delayed by reason of any reasonable
         unforeseeable cause beyond the reasonable control of the party liable
         to perform, the party so affected shall, upon giving written notice to
         the other party, be excused from such performance to the extent of such
         prevention, restriction, interference or delay, provided that the
         affected party shall use its commercially reasonable efforts to avoid
         or remove such causes of non-performance and shall continue performance
         with the utmost dispatch whenever such causes are removed. When such
         circumstances arise, the parties shall discuss what, if any,
         modification of the terms of this Agreement may be required in order to
         arrive at an equitable solution.

         ____________

*** Confidential material redacted and separately filed with the Commission.


                                   19
<PAGE>

15.      DISPUTE RESOLUTION

15.1     This Agreement shall be construed and enforced in accordance with the
         laws of the State of Delaware (without reference to the conflicts of
         law principles thereof).

15.2     In the event of any controversy, dispute or claim arising out of or
         relating to any provision of this Agreement or the breach thereof, the
         parties shall use good faith efforts to settle such controversy,
         dispute or claim amicably between themselves.

15.3     Should the parties fail to reach mutually acceptable settlement of any
         controversy, dispute or claim which may arise out of or in connection
         with this Agreement, or the breach, termination or validity thereof
         (other than with respect to patent validity) shall be settled by final
         and binding arbitration pursuant to the Commercial Arbitration Rules of
         the American Arbitration Association ("AAA") as herein provided.

         (a)      The Arbitration Tribunal shall consist of three arbitrators.
                  Each party shall nominate in the request for arbitration and
                  the answer thereto one arbitrator and the two arbitrators so
                  named will then jointly appoint the third arbitrator as
                  chairman of the Arbitration Tribunal. If one party fails to
                  nominate its arbitrator or, if the parties' arbitrators cannot
                  agree on the person to be named as chairman within sixty (60)
                  days, the necessary appointments shall be made under the rules
                  of the AAA.

         (b)      The place of arbitration shall be in Chicago, Illinois and the
                  arbitration proceedings shall be held in English. The
                  procedural law of the State of Illinois shall apply where the
                  AAA Rules are silent.

         (c)      The award of the Arbitration Tribunal shall be final and
                  judgment upon such an award may be entered in any competent
                  court or application may be made to any competent court for
                  judicial acceptance of such an award and order of enforcement.
                  Notwithstanding the foregoing, nothing contained herein shall
                  prevent either party from seeking interim relief from a court
                  of competent jurisdiction pending the establishment of or a
                  decision by a panel of arbitrators.


                                      20
<PAGE>

16.      ENTIRE AGREEMENT.

16.1     This Agreement, and the Appendices hereto, entered into as of the date
         written above together with the Investment Agreement and each of the
         documents referenced in such Investment Agreement, constitute the
         entire agreement between the parties relating to the subject matter
         hereof and supersedes all previous writings and understandings. No
         terms or provisions of this Agreement shall be varied or modified by
         any prior or subsequent statement, conduct or act of either of the
         parties, except that the parties may amend this Agreement by written
         instruments specifically referring to and executed in the same manner
         as this Agreement.

17.      NOTICES.

17.1     Any notice required or permitted under this Agreement shall be
         hand-delivered or sent by express delivery service or certified or
         registered mail, postage prepaid, or by fax with written confirmation
         by mail, to the following addresses of the parties:

                           VASCULAR GENETICS INC.
                           Suite 201
                           4364 S. Alston Avenue
                           Durham, North Carolina  27713
                           Attn: John W. Cumming
                           Fax:  (843) 342-3701

                           copy to:

                           Long Aldridge & Norman LLP
                           One Peachtree Center, Suite 5300
                           303 Peachtree Street, N.W.
                           Atlanta, GA  30308
                           Attn: Mark S. Lange, Esq.
                           Fax:  (404) 527-3808

                           VICAL INCORPORATED
                           9373 Towne Center Drive
                           San Diego, California  92121
                           Attn:  President
                           Fax:   (858) 646-1150


                                      21
<PAGE>

                           copy to:

                           Pillsbury Madison & Sutro LLP
                           50 Fremont Street
                           San Francisco, California 94105
                           Attn:  Thomas E. Sparks, Jr., Esq.
                           Fax:   (415) 983-1200

17.2     Any notice required or permitted to be given concerning this Agreement
         shall be effective upon receipt by the party to whom it is addressed.

18.      ASSIGNMENT AND CHANGE OF CONTROL.

18.1     This Agreement and the licenses herein granted shall be binding upon
         and inure to the benefit of the parties and their respective permitted
         assignees and successors in interest. Neither this Agreement nor any
         interest hereunder shall be assignable by a party without the prior
         written consent of the other party and any attempted assignment
         contrary to this Section 18.1 shall be void and without force and
         effect. Notwithstanding the foregoing; a party may assign this
         Agreement and all of its rights and obligations hereunder to any
         AFFILIATE or to any THIRD PARTY in connection with the transfer or sale
         of all or substantially all of its business or all or substantially all
         of its assets to which this Agreement relates, or in the event of its
         merger, consolidation, change in control or similar transaction,
         without obtaining the consent of the other party, provided that the
         assigning party remains liable under this Agreement and that the THIRD
         PARTY assignee or surviving entity assumes in writing all of its
         obligations under this Agreement.

19.      COUNTERPARTS.

19.1     This Agreement may be executed in any number of counterparts, and each
         such counterpart shall be deemed an original instrument, but all such
         counterparts together shall constitute but one agreement.


                                      22
<PAGE>

20.      WAIVER.

20.1     Any delay or failure in enforcing a party's rights under this Agreement
         or any waiver as to a particular default or other matter shall not
         constitute a waiver of such party's rights to the future enforcement of
         its rights under this Agreement, nor operate to bar the exercise or
         enforcement thereof at any time or times thereafter, excepting only as
         to an express written and signed waiver as to a particular matter for a
         particular period of time.

20.2     Notwithstanding the foregoing, in the event VGI challenges whether any
         payments contemplated hereunder (including, without limitation
         royalties or milestones) are due, it shall have the right, but not the
         obligation, to make such payments under protest (reserving all rights
         hereunder) pending resolution of such dispute.

21.      INDEPENDENT RELATIONSHIP.

21.1     Nothing herein contained shall be deemed to create an employment,
         agency, joint venture or partnership relationship between the parties
         hereto or any of their agents or employees, or any other legal
         arrangement that would impose liability upon one party for the act or
         failure to act of the other party. No party shall have any power to
         enter into any contracts or commitments or to incur any liabilities in
         the name of, or on behalf of, the other party, or to bind the other
         party in any respect whatsoever.

22.      FURTHER ACTIONS.

22.1     Each party agrees to execute, acknowledge and deliver such further
         instruments and to do all such other acts, as may be necessary or
         appropriate in order to carry out the purposes and intent of this
         Agreement.


                                      23
<PAGE>

         IN WITNESS WHEREOF, the parties, through their authorized officers,
have executed this Agreement as of the Effective Date.



VICAL INCORPORATED



By:  /s/ Alain B. Shreiber, M.D.
   -----------------------------
     Alain B. Schreiber, M.D.
     President and Chief Executive Officer



VASCULAR GENETICS INC.



By:  /s/ John W. Cumming
   -----------------------------
     John W. Cumming
     President




                                      24
<PAGE>

                                 APPENDIX A ***





























         ____________

*** Confidential material redacted and separately filed with the Commission.


                                      1