EXHIBIT 3.18

    CONFIDENTIAL TREATMENT HAS BEEN REQUESTED FOR PORTIONS OF THIS DOCUMENT.
                  CONFIDENTIAL PROVISIONS HAVE BEEN OBSCURED.

                         NON-EXCLUSIVE LICENSE AGREEMENT

     This Non-exclusive License Agreement (the "Agreement"), effective as of
November 30, 2001 (the "Effective Date"), is entered into by and between XOMA
Ireland Limited ("XOMA"), an Irish company having offices located at Shannon
Airport House, Shannon, County Clare, Ireland, and Viventia Biotech Inc.
("VIVENTIA"), a Canadian corporation having offices located at 10 Four Seasons
Place, Suite 510, Toronto, Ontario, Canada M9B 6H7.

                                   BACKGROUND

     A. XOMA is the owner of certain Patent Rights and Know-How (as such terms
are defined below) and VIVENTIA wishes to acquire a non-exclusive license under
the Patent Rights and Know-How; and

     B. XOMA is willing to grant VIVENTIA such a non-exclusive license, on the
terms and conditions set forth below.

     NOW, THEREFORE, in consideration of the promises and the mutual covenants
hereinafter recited, the parties agree as follows:


ARTICLE 1 -- DEFINITIONS

     In this Agreement, the following terms shall have the meanings set forth in
this Article.

     1.1 "Affiliate" means any corporation or other entity which is directly or
indirectly controlling, controlled by or under common control with a party
hereto. For the purpose of this Agreement, "control" shall mean the direct or
indirect ownership of at least fifty percent (50%) of the outstanding shares or
other voting rights of the subject entity to elect directors.

     1.2 "BLA" means a Biologics License Application (or, if applicable, a
Product License Application), as defined in the U.S. Food, Drug and Cosmetic Act
and the regulations promulgated thereunder, and any corresponding U.S. or
foreign application, registration or certification.

     1.3. "Confidential Information" shall mean (i) any proprietary or
confidential information or material in tangible form disclosed hereunder that
is designated as "Confidential" at the time it is delivered to the receiving
party, or (ii) proprietary or confidential information disclosed orally
hereunder which is identified as confidential or proprietary when disclosed and
such disclosure of confidential information is confirmed in writing within
thirty (30) days by the disclosing party.

                                       1




     1.4 "Field" shall mean the treatment or prophylaxis of a human or animal
disease state or condition and shall exclude Phage Display.

     1.5 "Immunoglobulin" means any molecule that has an amino acid sequence by
virtue of which it specifically interacts with an antigen and wherein any chains
of the molecule contain a functionally operating region of an antibody variable
region including, without limitation, any naturally occurring or recombinant
form of such a molecule.

     1.6 "IND" shall mean an Investigational New Drug application, as defined in
the U.S. Food, Drug and Cosmetic Act and the regulations promulgated thereunder
for initiating clinical trials in the United States, or any corresponding
foreign application, registration or certification.

     1.7 "Know-How" means unpatented and/or unpatentable technical information,
including ideas, concepts, inventions, discoveries, data, designs, formulas,
specifications, procedures for experiments and tests and other protocols,
results of experimentation and testing, fermentation and purification
techniques, and assay protocols owned by XOMA as of the Effective Date which may
be necessary for the practice of the Patent Rights, which XOMA has the right to
license, and which have been transmitted to VIVENTIA. Know-How shall not include
the Patent Rights. All Know-How shall be Confidential Information of XOMA.

     1.8 "Licensed Product" will mean any product within the scope of a Valid
Claim or produced using any method within the scope of a Valid Claim, or which
incorporates or is made using any Know-How, provided however, that the term
Licensed Product shall not include Phage Display Materials or any Product which
is discovered, isolated, characterized or produced by the use of Phage Display.

     1.9 "Licensed Technology" means the Patent Rights and Know-How.

     1.10 "NDA" shall mean a New Drug Application, as defined in the U.S. Food,
Drug and Cosmetic Act and the regulations promulgated thereunder, or any
corresponding U.S. or foreign application, registration or certification.

     1.11 "Net Sales" shall mean revenues received by VIVENTIA or its
Affiliates, as follows: the invoice price of Licensed Products sold by VIVENTIA
or its marketing partner(s) to third parties, less, to the extent included in
such invoice price the total of: (1) ordinary and customary trade discounts
actually allowed; (2) credits, rebates and returns (including, but not limited
to, wholesaler and retailer returns); (3) freight, postage, insurance and duties
paid for and separately identified on the invoice or other documentation
maintained in the ordinary course of business, and (4) excise taxes, other
consumption taxes, customs duties and compulsory payments to governmental
authorities actually paid and separately identified on the invoice or other
documentation maintained in the ordinary course of business. Net Sales shall
also include the fair market value of all other consideration received by
VIVENTIA or its marketing partner(s) in respect of Licensed Products, whether
such consideration is in cash,

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payment in kind, exchange or another form, but shall not include any payments
received for reimbursement of research expenses, including but not limited to
the conduct of clinical trials, or for the purchase of debt or equity of
VIVENTIA. In the case of pharmacy incentive programs, hospital performance
incentive program chargebacks and/or similar programs or discounts on "bundles"
of products, VIVENTIA may, with notice to XOMA, discount the bona fide list
price of a Licensed Product by the average percentage discount of all VIVENTIA
products in a particular "bundle," calculated as follows:

        
                                                         
        [          ]                             [   ]
        [     ]                         [   ]    [   ]     [   ]     [         ]
        [             ]
        

[



              ] If a Licensed Product is not sold separately and no bona fide
list price exists for such Licensed Product, the parties shall negotiate in good
faith an imputed bona fide list price for such Licensed Product.

     1.12 "Patent Rights" shall mean the patent applications and patents listed
on Exhibit A hereto and all divisions, continuations, continuations-in-part, and
substitutions thereof; all foreign patent applications corresponding to the
preceding applications or directly or indirectly claiming priority to or from
any of the forgoing; and all U.S. and foreign patents issuing on any of the
preceding applications, including extensions, reissues, and re-examinations.

     1.13 "Phage Display" means the use of Phage Display Materials.

     1.14 "Phage Display Materials" means (i) any collection or library of
polynucleotide sequences which encodes at least one polypeptide and which is
contained in filamentous bacteriophage and/or bacteriophage or phagmid cloning
vectors capable of propagation in bacteria; or (ii) any collection of library of
bacteriophage wherein a polypeptide is expressed as a fusion protein comprising
the polypeptide and an outer surface polypeptide of a bacteriophage. For the
avoidance of doubt, Phage Display Materials shall include any such materials
wherein the polypeptide in an Immunoglobulin.

     1.15 "Phase II" or "Phase III" shall mean a Phase II or Phase III clinical
trial as prescribed by applicable FDA regulations, or corresponding regulations
of any comparable entity.

     1.16 "Product" means any composition of matter or article of manufacture,
including, without limitation any diagnostic, prophylactic or therapeutic
product, which was discovered

                                        3



or created by or arose out of or is related to use of Licensed Materials, and is
made or sold under conditions which, if unlicensed, would constitute
infringement of the XOMA Patent Rights.

     1.17 "Third Party" means any person or entity other than VIVENTIA or XOMA.

     1.18 "Valid Claim" means (i) a claim of an issued and unexpired patent
included within the Patent Rights which claim has not been held invalid in a
final decision of a court of competent jurisdiction from which no appeal may be
taken, and which has not been disclaimed or admitted to be invalid or
unenforceable through reissue or otherwise, or (ii) a claim of a published
patent application within the Patent Rights.


ARTICLE 2 -- LICENSE

     2.1 Grant. Subject to the terms and conditions of this Agreement, XOMA
hereby grants to VIVENTIA a non-exclusive, non-transferable, worldwide license
under the Licensed Technology, without the right to grant sublicenses, to make,
have made, use, import, offer for sale and sell Licensed Products for use in the
Field, provided that VIVENTIA shall have the right to grant one sublicense in
each country to a marketing partner for sale of Licensed Products for use in the
field.

     2.2 No Implied Rights. Only the rights and licenses granted pursuant to the
express terms of this Agreement shall be of any legal force or effect. No
license or other rights shall be deemed to have been granted to VIVENTIA other
than as expressly provided for in this Agreement. For the avoidance of doubt,
the license grants pursuant to Section 2.1 do not include, and expressly
exclude, the following:

     (a) any right or license to engage in or cause any Third Party to engage in
Phage Display or to use any Phage Display Materials to identify, select,
characterize, study or test a polypeptide, including but not limited to an
Immunoglobulin;

     (b) any right or license to engage in any Phage Display activities on
behalf of or in collaboration with any Third Party;

     (c) any right or license under the XOMA Patent Rights to commercialize any
Product based upon or derived from use of Phage Display Materials or Phage
Display;

     (d) any right or license under the XOMA Patent Rights to sell, lease,
license, transfer or dispose of the ownership or possession of any Phage Display
Materials; and

     (e) any right to release any Third Party from any claim of infringement
under the XOMA Patent Rights.


                                        4


     2.3 Delivery of Know-How. Within thirty (30) days following receipt by XOMA
of VIVENTIA's payment of the access fee under Section 3.1 of this Agreement,
XOMA shall deliver to VIVENTIA the Know-How listed on Exhibit B hereto.

     2.4 Ownership; Enforcement. At all times XOMA will retain ownership of the
[ OMA Patent Rights and may use and commercialize the [ OMA Patent Rights itself
or with any Third Party for any purpose whatsoever. XOMA retains the right, at
its sole discretion, to enforce, maintain and otherwise protect the XOMA Patent
Rights. Within thirty (30) days of the Effective Date, and at all times
thereafter during the term of this Agreement, VIVENTIA shall give XOMA prompt
notice in writing of all information or facts in its possession which identify
or are reasonably likely to lead to the identification of any unauthorized use
of the XOMA Patent Rights, including without limitation the conduct of any
activities outside of the scope of the license grants pursuant to Section 2.1.
VIVENTIA, at XOMA's expense, shall cooperate with XOMA's reasonable written
demands to VIVENTIA with respect to any actions XOMA may choose to take related
to the enforcement, maintenance or protection of the XOMA Patent Rights.

     2.5 Oppositions and/or Appeals. VIVENTIA hereby agrees not to enter into
any opposition to and/or appeal from any decision by the patent authorities of
any country on the XOMA Patent Rights, and shall not assist or otherwise
cooperate with another party in any such opposition or appeal.


ARTICLE 3 -- CONSIDERATION

     3.1 Access Fee. VIVENTIA shall pay XOMA by wire transfer a technology
access fee of [
            ] in two (2) payments as follows: [
                       ] will be paid to XOMA within ten (10) days after
the receipt by VIVENTIA of one fully executed copy of this Agreement, and [
                                         ] will be paid to XOMA on or
before the first anniversary of the receipt by VIVENTIA of the copy of the
Agreement. Technology transfer is included in the access fee and includes up to
two person-days of XOMA scientific staff time during the first twelve months of
the term of this Agreement. Thereafter, VIVENTIA will be able to consult with
XOMA scientific staff at $[    ]/person-day (based on an eight hour day) beyond
the two person-days. The cost of all reasonable travel-related expenses,
including travel-related expenses for the first two person-days, will be fully
reimbursed to XOMA by VIVENTIA.

     3.2 Milestone Payments. Within thirty (30) days following the achievement
by VIVENTIA of the following milestones with respect to each Licensed Product,
VIVENTIA shall pay to XOMA the applicable payments below:


                                        5


        
        
        Event                                                                  Payment
        -----                                                                  -------
                                                                            
        Initiation of a first [                   ]                            [             ]
        Initiation of a first [                          ]                     [           ]
        Regulatory approval [          ] for marketing                         [           ]
        




     3.3 Royalties.

     (a) VIVENTIA shall pay to XOMA a royalty of [             ] percent
([  ]%) on all Net Sales of Licensed Products.

     (b) VIVENTIA shall receive a credit for royalties it pays to third parties
on account of Licensed Products on a country-by-country basis against royalties
due to XOMA pursuant to this Agreement; provided, however, that in no event
shall royalties due to XOMA with respect to Licensed Products be reduced to less
than [                ] percent ([  ]%) in any country.

     (c) The foregoing royalty rates shall be reduced by [    ] percent ([  ]%)
with respect to Licensed Products which are not within the scope of a Valid
Claim in the country of sale.

     3.4 One Royalty. No more than one royalty payment shall be due hereunder
with respect to a sale of a particular Licensed Product. No multiple royalties
shall be payable because any Licensed Product or its manufacture, sale or use is
covered by more than one Valid Claim.

     3.5 Royalty Term. Royalties due under this Article 3 shall be payable on a
country-by-country and Licensed Product-by-Licensed Product basis from the first
commercial sale of such Licensed Product until the expiration of the
last-to-expire Patent Right in such country with respect to which a Valid Claim
covers the manufacture, use, sale, offer for sale, import or export of such
Licensed Product, or until the tenth anniversary of the first commercial sale of
a particular Licensed Product in such country, whichever is later.


ARTICLE 4 -- PAYMENTS; REPORTS AND RECORDS

     4.1 Payments; Currency. All payments due hereunder shall be paid by wire
transfer in United States dollars in immediately available funds to an account
designated by XOMA. If any currency conversion shall be required in connection
with the payment of any royalties hereunder, such conversion shall be made by
using the exchange rate for the purchase of U.S. dollars quoted in the U.S.
version of the Wall Street Journal on the last business day of the calendar
quarter to which such royalty payments relate.

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     4.2 Royalty Reports and Payments. After the first commercial sale of a
Licensed Product on which royalties are required to be paid hereunder, VIVENTIA
shall make quarterly written reports to XOMA within sixty (60) days after the
end of each calendar quarter, stating in each such report, by country, the
number, description, and aggregate Net Sales of each Licensed Product sold
during the calendar quarter. XOMA shall treat all such reports as Confidential
Information of VIVENTIA. Concurrently with the making of such reports, VIVENTIA
shall pay XOMA the royalties specified in Section 3.3 hereof.

     4.3 Records; Inspection. VIVENTIA shall keep complete, true and accurate
books of account and records for the purpose of determining the royalty amounts
payable under this Agreement. Such books and records shall be kept at the
principal place of business of VIVENTIA for at least three (3) years following
the end of the calendar quarter to which they pertain and will be available for
inspection during such period by a representative of XOMA for the purpose of
verifying the royalty reports and payments. Such inspections shall be made
during ordinary business hours. The representative may be obliged to execute a
reasonable confidentiality agreement prior to commencing any such inspection.
Inspections conducted under this Section 4.3 shall be at the expense of XOMA,
unless an underpayment exceeding [ ] percent ([ ]%) of the amount stated for
the full period covered by the inspection is identified, in which case all
out-of-pocket costs relating to the inspection will be paid immediately by
VIVENTIA. Any underpayments or unpaid amounts discovered by such inspections or
otherwise will be paid immediately by VIVENTIA, with interest from the date(s)
such amount(s) were due at the prime rate reported by the Bank of America plus
two percent (2%).


ARTICLE 5 -- DILIGENCE

     5.1 Reasonable Efforts. VIVENTIA agrees to use reasonable efforts
consistent with its prudent business judgment to diligently develop and
commercialize the Patent Rights and obtain such approvals as may be necessary
for the sale of the Licensed Products in the United States and such other
worldwide markets as VIVENTIA elects to commercialize the Licensed Products.

     5.2 Reports to XOMA. During the term of this Agreement, VIVENTIA shall keep
XOMA reasonably informed of its activities subject to this Agreement, including
without limitation, the achievement of the milestones set forth in Section 3.2
for the commercialization of each Licensed Product, and within thirty (30) days
following November 30 of each year shall provide XOMA with a written report
indicating the current status of each program involving a Licensed Product. When
the registration package requesting approval for commercial sale of each
Licensed Product is first filed in each of the U.S., Europe and Japan, and in
each case when approval is received therefor, VIVENTIA will promptly notify
XOMA. VIVENTIA shall notify XOMA within thirty (30) days after the first
commercial sale of each Licensed Product.


                                        7



ARTICLE 6 -- CONFIDENTIALITY

     6.1 Confidential Information. Except as expressly provided herein, the
parties agree that, for the term of this Agreement and for five (5) years
thereafter, the receiving party shall keep completely confidential and shall not
publish or otherwise disclose and shall not use for any purpose except for the
purposes contemplated by this Agreement any Confidential Information furnished
to it by the disclosing party hereto, except that to the extent that it can be
established by the receiving party by written proof that such Confidential
Information:

     (a) was already known to the receiving party, other than under an
obligation of confidentiality, at the time of disclosure;

     (b) was generally available to the public or otherwise part of the public
domain at the time of its disclosure to the receiving party;

     (c) became generally available to the public or otherwise part of the
public domain after its disclosure and other than through any act or omission of
the receiving party in breach of this Agreement; or

     (d) was subsequently lawfully disclosed to the receiving party by a person
other than a party hereto.

     6.2 Permitted Use and Disclosures. Each party hereto may use or disclose
information disclosed to it by the other party to the extent such use or
disclosure is reasonably necessary in complying with applicable law or
governmental regulations or conducting clinical trials; provided that if a party
is required to make any such disclosure of another party's Confidential
Information, other than pursuant to a confidentiality agreement, it will give
reasonable advance notice to the latter party of such disclosure and will use
its reasonable best efforts to secure confidential treatment of such information
prior to its disclosure (whether through protective orders or otherwise).

     6.3 Confidential Terms. Except as expressly provided herein, each party
agrees not to disclose any terms of this Agreement to any third party without
the consent of the other party; provided, disclosures may be made as required by
securities or other applicable laws, or to actual or prospective corporate
partners, or to a party's accountants, attorneys and other professional
advisors.

     6.4 Agreement Announcement. The parties hereby agree that the consummation
of this Agreement shall be deemed to be in the public domain and may be
announced or otherwise referred to by the parties as they deem appropriate.


                                        8


ARTICLE 7 -- REPRESENTATIONS AND WARRANTIES

     7.1 Representations and Warranties. XOMA represents and warrants that: (a)
it is the sole and exclusive owner of all right, title and interest in the
Patent Rights; and (b) it has the right to grant the license granted herein.

     7.2 Disclaimer. Nothing in this Agreement is or shall be construed as:

     (a) A warranty or representation by XOMA as to the validity or scope of any
claim or patent within the Patent Rights;

     (b) A warranty or representation that anything made, used, sold, or
otherwise disposed of under any license granted in this Agreement is or will be
free from infringement of any patent rights or other intellectual property right
of any third party;

     (c) An obligation to bring or prosecute actions or suits against third
parties for infringement of any of the Patent Rights or misappropriation of any
Know-How; or

     (d) Granting by implication, estoppel, or otherwise (except as expressly
set forth herein) any licenses or rights under patents or other rights of XOMA
or third parties, regardless of whether such patents or other rights are
dominant or subordinate to any patent within the Patent Rights.

     7.3 No Warranties. EXCEPT AS PROVIDED IN SECTION 7.1 ABOVE XOMA GRANTS NO
WARRANTIES WITH RESPECT TO THE LICENSED TECHNOLOGY, EXPRESS OR IMPLIED, EITHER
IN FACT OR BY OPERATION OF LAW, BY STATUTE OR OTHERWISE, AND XOMA SPECIFICALLY
DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE, VALIDITY OF THE PATENT RIGHTS OR NON-INFRINGEMENT OF THE
INTELLECTUAL PROPERTY RIGHTS OF ANY THIRD PARTY.


ARTICLE 8 -- INDEMNIFICATION

     VIVENTIA agrees to indemnify, defend and hold XOMA and its directors,
officers, employees and agents harmless from and against any and all third party
liabilities, claims, demands, expenses (including, without limitation, attorneys
and professional fees and other costs of litigation), losses or causes of action
(each, a "Liability") arising out of or relating in any way to (i) the
possession, manufacture, use, sale or other disposition of Licensed Products,
whether based on breach of warranty, negligence, product liability or otherwise,
(ii) the exercise of any right granted to VIVENTIA pursuant to this Agreement,
or (iii) any breach of this Agreement by VIVENTIA, except to the extent, in each
case, that such Liability is caused by the negligence or willful misconduct of
XOMA, or (b) breach by XOMA as determined by a court of competent jurisdiction.


                                        9


ARTICLE 9 -- TERM AND TERMINATION

     9.1 Term. The term of this Agreement will commence on the Effective Date
and remain in full force and effect until the expiration of the last patent
within the Patent Rights, or the tenth anniversary of the first commercial sale
of a Licensed Product, whichever is later, unless earlier terminated in
accordance with this Article 9.

     9.2 Termination for Cause. Either party may terminate this Agreement in the
event the other party has materially breached or defaulted in the performance of
any of its obligations hereunder, and such default has continued for sixty (60)
days after written notice thereof was provided to the breaching party by the
nonbreaching party. The parties hereby agree that a breach of Section 2.5 is
considered to be a material breach of this Agreement. Any termination shall
become effective at the end of such sixty (60) day period unless the breaching
party has cured any such breach or default prior to the expiration of such
period. Notwithstanding the above, in the case of a failure to pay any amount
due hereunder the period for cure of any such default following notice thereof
shall be ten (10) days and, unless payment is made within such period, the
termination shall become effective at the end of such period.

     9.3 Termination for Insolvency. If voluntary or involuntary proceedings by
or against a party are instituted in bankruptcy under any insolvency law, or a
receiver or custodian is appointed for such party, or proceedings are instituted
by or against such party for corporate reorganization or the dissolution of such
party, which proceedings, if involuntary, shall not have been dismissed within
sixty (60) days after the date of filing, or if such party makes an assignment
for the benefit of creditors, or substantially all of the assets of such party
are seized or attached and not released within sixty (60) days thereafter, the
other party may immediately terminate this Agreement effective upon notice of
such termination.

     9.4 Effect of Termination.

     (a) Accrued Rights and Obligations. Termination of this Agreement for any
reason shall not release any party hereto from any liability which, at the time
of such termination, has already accrued to the other party or which is
attributable to a period prior to such termination nor preclude either party
from pursuing any rights and remedies it may have hereunder or at law or in
equity with respect to any breach of this Agreement. It is understood and agreed
that monetary damages may not be a sufficient remedy for any breach of this
Agreement and that the non-breaching party may be entitled to injunctive relief
as a remedy for any such breach. Such remedy shall not be deemed to be the
exclusive remedy for any such breach of this Agreement, but shall be in addition
to all other remedies available at law or in equity.

     (b) Return of Confidential Information. Upon any termination of this
Agreement, VIVENTIA and XOMA shall promptly return to the other party all
Confidential Information, including without limitation, any Know-How received
from the other party (except XOMA may retain copies of any reports or records
referred to in Article 4 or 5).


                                       10


     (c) Stock on Hand. In the event this Agreement is terminated for any
reason, VIVENTIA shall have the right to sell or otherwise dispose of the stock
of any Licensed Product then on hand until six (6) months after such
termination, subject to Articles 3 and 4 and the other applicable terms of this
Agreement.

     (d) Licenses. All licenses granted hereunder shall terminate upon the
termination of this Agreement.

     9.5 Survival. Sections 9.4 and 9.5, and Articles 4, 6, 7, 8 and 10 of this
Agreement shall survive the expiration or termination of this Agreement for any
reason.

     9.6 Contested Validity. If VIVENTIA or any of its Affiliates attacks,
contests or otherwise disparages or assists another in attacking, contesting or
otherwise disparaging the validity of any of the Patent Rights licensed
hereunder in any proceeding in any court of competent jurisdiction, including
any patent opposition or appeal proceeding involving or relating to the Patent
Rights, XOMA shall have the right to terminate this Agreement by written notice.


ARTICLE 10 -- MISCELLANEOUS PROVISIONS

     10.1 Governing Law. This Agreement shall be construed in accordance with
the laws of Canada, the State of California and/or the United States of America
which are applicable to contracts negotiated, executed and performed within the
State of California in the United States of America. In addition, the parties
agree to comply with all applicable laws, rules and regulations of Canada,
California and the United States of America, including all export and import
laws, and to do nothing to cause XOMA or VIVENTIA to violate any such laws,
rules and/or regulations.


     10.2 Assignment. VIVENTIA may not transfer or assign this Agreement or any
of VIVENTIA's rights hereunder without the prior written consent of XOMA, such
consent not to be unreasonably withheld, provided that VIVENTIA may assign this
Agreement to an Affiliate or a purchaser of VIVENTIA or the business unit of
VIVENTIA to which this Agreement pertains without consent of XOMA, which consent
will not be unreasonably withheld. Any such attempted transfer or assignment
shall be void. This Agreement shall be binding upon and inure to the benefit of
the parties and their permitted successors and assigns.

     10.3 Waiver. No waiver of any rights shall be effective unless consented to
in writing by the party to be charged and the waiver of any breach or default
shall not constitute a waiver of any other right hereunder or any subsequent
breach or default.

     10.4 Severability. In the event that any provisions of this Agreement are
determined to be invalid or unenforceable by a court of competent jurisdiction,
the remainder of the Agreement shall remain in full force and effect without
said provision.


                                       11


         10.5 Notices. All notices, requests and other communications hereunder
shall be in writing and shall be personally delivered or sent by telecopy or
other electronic facsimile transmission or by registered or certified mail, and
shall be effective upon receipt at the respective address specified below, or
such other address as may be specified in writing to the other parties hereto:


                
                                     
                LICENSEE:               Vice President, Corporate Development
                                        Viventia Biotech Inc.
                                        10 Four Seasons Place, Suite 501
                                        Toronto, Ontario
                                        Canada M9B 6H7

                With a copy to:         Chief Financial Officer

                XOMA:                   XOMA Ireland Limited
                                        Shannon Airport House
                                        Shannon, County Clare
                                        Ireland

                With a copy to:         Christopher J. Margolin
                                        Vice President, General Counsel
                                        and Secretary
                                        XOMA (US) LLC
                                        2910 Seventh Street
                                        Berkeley, CA  94710
                  

     10.6 Independent Contractors. Both parties are independent contractors
under this Agreement. Nothing contained in this Agreement is intended nor is to
be construed so as to constitute XOMA or VIVENTIA as partners or joint venturers
with respect to this Agreement. Neither party shall have any express or implied
right or authority to assume or create any obligations on behalf of or in the
name of the other party or to bind the other party to any other contract,
agreement, or undertaking with any third party.

     10.7 Patent Marking. VIVENTIA agrees to mark all Licensed Products sold
pursuant to this Agreement in accordance with the applicable statute or
regulations relating to patent marking in the country or countries of
manufacture and sale thereof.

     10.8 Compliance with Laws. In exercising their rights under this license,
the parties shall fully comply in all material respects with the requirements of
any and all applicable laws, regulations, rules and orders of any governmental
body having jurisdiction over the exercise of rights under this Agreement.
VIVENTIA shall be responsible, at its expense, for making any



                                       12


required registrations or filings with respect to this Agreement and obtaining
any necessary governmental approvals with respect hereto.


     10.9 Use of Name. Except as provided in Section 6.4, neither party shall
use the name or trademarks of the other party without the prior written consent
of such other party.

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

     10.11 Entire Agreement; Amendment. This Agreement constitutes the entire
and exclusive Agreement between the parties with respect to the subject matter
hereof and supersedes and cancels all previous discussions, agreements,
commitments and writings in respect thereof. No amendment or addition to this
Agreement shall be effective unless reduced to writing and executed by the
authorized representatives of the parties.

     IN WITNESS WHEREOF, XOMA and VIVENTIA have executed this Agreement in
duplicate originals by duly authorized officers.



VIVENTIA BIOTECH INC.                                XOMA IRELAND LIMITED

                                                  
By:    /s/ Anthony Schincariol                       By:    /s/ Alan Kane
       -------------------------------------                -------------------------------------
       Anthony Schincariol, Ph.D.                           Alan Kane, Director
       President & CEO                                      duly authorized on behalf of
       Viventia Biotech Inc.                                XOMA Ireland Limited in the
                                                            presence of the following witness:

Date:  November 26, 2001
       -------------------------------------

       /s/ Nick Glover                                      /s/ Brian Cunnea
       -------------------------------------                -------------------------------------
       Nick Glover, Ph.D.                                   Solicitor
       Vice-President, Corporate Development
       Viventia Biotech Inc.

Date:  November 26, 2001                             Date:  November 29, 2001
       -------------------------------------                -------------------------------------


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    CONFIDENTIAL TREATMENT HAS BEEN REQUESTED FOR PORTIONS OF THIS DOCUMENT.
                  CONFIDENTIAL PROVISIONS HAVE BEEN OBSCURED.

                                    EXHIBIT A
                                  Patent Rights

Title:      Modular Assembly of Antibody Genes, Antibodies Prepared Thereby and
            Use

Inventors:  Robinson, Liu, Horwitz, Wall, Better


1)       Based on PCT/US86/02269, which is a continuation-in-part of U.S. Serial
         No. 06/793,980 filed November 1, 1985 (abandoned).

         
         
         COUNTRY                          SERIAL NO.                 PATENT NO.
         -------                          ----------                 ----------
                                                               
         *United States                   06/793,980
         Australia                        65981/86                   Issued  606,320
         Canada                           521,909                    Abandoned
         Denmark                          3385/87                    Pending
         Taiwan                           75105650                   Issued  51922
         *United States                   06/086,266
         

2)      Based on PCT/US88/02514, which corresponds to U.S. Serial
        No. 07/077,528, which is a continuation-in-part of 06/086,266
        (abandoned), which is a continuation-in-part of U.S. Serial
        No. 06/793,980 (abandoned).

        
        
        COUNTRY                              SERIAL NO.                         PATENT NO.
        -------                              ----------                         ----------
                                                                          
        Australia                            23244/88                           Issued   632,462
        Austria                              EP 88907510.7                      Granted EP/0371998
        Belgium                              EP 88907510.7                      Granted EP/0371998
        Canada                               572,398                            Pending
        Denmark                              192/90                             Pending
        Europe                               EP 88907510.7                      Granted EP/0371998
        Europe                               EP 95119798.7                      Allowed (divisional)
        France                               EP 88907510.7                      Granted EP/0371998
        Germany                              EP 88907510.7                      Granted EP/0371998
        Italy                                EP 88907510.7                      Granted EP/0371998
        Japan                                506481/88                          Granted 2991720
        Luxembourg                           EP 88907510.7                      Granted EP/0371998
        Netherlands                          EP 88907510.7                      Granted EP/0371998
        Sweden                               EP 88907510.7                      Granted EP/0371998
        Switzerland/
        Liechtenstein                        EP 88907510.7                      Granted EP/0371998
        United Kingdom                       EP 88907510.7                      Granted EP/0371998
        Europe                               EP 93100041.8                      Granted EP/0550400
        Austria                              EP 93100041.8                      Granted EP/0550400
        Belgium                              EP 93100041.8                      Granted EP/0550400
        France                               EP 93100041.8                      Granted EP/0550400
        Germany                              EP 93100041.8                      Granted EP/0550400
        Italy                                EP 93100041.8                      Granted EP/0550400
        Luxembourg                           EP 93100041.8                      Granted EP/0550400
        Netherlands                          EP 93100041.8                      Granted EP/0550400
        Sweden                               EP 93100041.8                      Granted EP/0550400
        Switzerland/
        Liechtenstein                        EP 93100041.8                      Granted EP/0550400

       
                                        1


        
        
        COUNTRY                              SERIAL NO.                         PATENT NO.
        -------                              ----------                         ----------
                                                                          
        United Kingdom                       EP 93100041.8                      Granted EP/0550400
        *United States                       07/077,528
        

*Cases abandoned in favor of a continuing application.

3)      Based on U.S. Serial No. 07/501,092 filed March 29, 1990, which is a
        continuation-in-part of U.S. Serial No. 07/077,528 (Modular Assembly of
        Antibody Genes, Antibodies Prepared Thereby and Use; Robinson, Liu,
        Horwitz, Wall, Better) and of U.S. Serial No. 07/142,039 (Novel Plasmid
        Vector with Pectate Lyase Signal Sequence; Lei, Wilcox).

        
        
        COUNTRY                              SERIAL NO.                         PATENT NO.
        -------                              ----------                         ----------
                                                                          
        *United States                       07/501,092
        *United States                       07/987,555
        *United States                       07/870,404
        *United States                       08/020,671
        United States                        08/235,225                         5,618,920
        United States                        08/299,085                         5,595,898
        United States                        08/357,234                         5,576,195
        United States                        08/472,696                         5,846,818
        United States                        08/472,691                         Allowed
        United States                        08/467,140                         5,698,435
        United States                        08/450,731                         5,693,493
        United States                        08/466,203                         5,698,417
        


Title:      AraB Promoters and Method of Producing Polypeptides, Including
            Cecropins, by Microbiological Techniques

Inventors:  Lai, Lee, Lin, Ray, Wilcox

         Based on PCT/US86/00131, which is a continuation-in-part of U.S.
         Serial No. 06/695,309 filed January 28, 1985 (abandoned).

         
         
         COUNTRY                              SERIAL NO.                        PATENT NO.
         -------                              ----------                        ----------
                                                                          
         Austria                              EP 86900983.7                     Granted EP/0211047
         Belgium                              EP 86900983.7                     Granted EP/0211047
         Europe                               EP 86900983.7                     Granted EP/0211047
         Finland                              863891                            Granted 94774
         France                               EP 86900983.7                     Granted EP/0211047
         Germany                              EP 86900983.7                     Granted P3689598.9-08
         Italy                                EP 86900983.7                     Granted EP/0211047
         Japan                                500818/86                         Granted 2095930
         Japan                                094753/94                         Granted 2121896
         Luxembourg                           EP 86900983.7                     Granted EP/0211047
         Netherlands                          EP 86900983.7                     Granted EP/0211047
         Norway                               863806                            Granted 175870
         Sweden                               EP 86900983.7                     Granted EP/0211047
         Switzerland/
         Liechtenstein                        EP 86900983.7                     Granted EP/0211047
         United Kingdom                       EP 86900983.7                     Granted EP/0211047
         

                                        2


         
         
         COUNTRY                              SERIAL NO.                        PATENT NO.
         -------                              ----------                        ----------
                                                                          
         *United States                       06/695,309
         *United States                       06/797,472
         United States                        07/474,304                        Granted 5,028,530
         

*Cases abandoned in favor of a continuing application.


Title:      Novel Plasmid Vector with Pectate Lyase Signal Sequence

Inventors:  Lei, Wilcox

        Based on U.S. Serial No. 07/142,039 filed January 11, 1988 and
        PCT/US89/00077.

        
        
        COUNTRY                              SERIAL NO.                         PATENT NO.
        -------                              ----------                         ----------
                                                                          
        Australia                            29377/89                           Issued/627443
        Canada                               587,885                            1,338,807
        Europe                               EP 89901763.6                      Granted EP/0396 612
        Austria                              EP 89901763.6                      Granted EP/0396 612
        Belgium                              EP 89901763.6                      Granted EP/0396 612
        France                               EP 89901763.6                      Granted EP/0396 612
        Germany                              EP 89901763.6                      Granted EP/0396 612
        Italy                                EP 89901763.6                      Granted EP/0396 612
        Luxembourg                           EP 89901763.6                      Granted EP/0396 612
        Netherlands                          EP 89901763.6                      Granted EP/0396 612
        Sweden                               EP 89901763.6                      Granted EP/0396 612
        Switzerland/
        Liechtenstein                        EP 89901763.6                      Granted EP/0396 612
        United Kingdom                       EP 89901763.6                      Granted EP/0396 612
        Japan                                501661/89                          Granted 2980626
        *United States                       07/142,039
        
 *Cases abandoned in favor of a continuing application.


                                       3



                                    EXHIBIT B

                           Delivery of Know-How (2.3)



1.   Plasmid DNA

2.   Plasmid Maps

3.   Expression Strain

4.   Lab-Scale Production (including, but not limited to, recombinant
     immunotoxin production Know-How)

5.   Fermentation Production (including, but not limited to, recombinant
     immunotoxin production Know-How)


                                       4