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                                                                   EXHIBIT 10.11


               ENGLISH TRANSLATION (the French text shall prevail)



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                            PATENT LICENSE AGREEMENT

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                                     BETWEEN

THE REGION WALLONNE

Represented by Mr. Jean-Pierre GRAFE Secretary of Research, Technological
development, Sport and International relations, Rue de la Loi, 38 - 1040-
BRUSSELS,

Hereafter the "REGION",

THE UNIVERSITE CATHOLOIQUE DE LOUVAIN

Represented by Mr. Marcel CROCHET, Rector and by the Lecturer Andre TROUET,
Place de l'Universite, 1 - 1348 - LOUVAIN-LA-NEUVE,

Hereafter the "UNIVERSITY",

                                       AND

The societe anonyme COULTER PHARMACEUTICAL BELGIUM to be incorporated

Represented by Dr. Arnold L. ORONSKY, President and Chief executive Officer of
the American company COULTER PHARMACEUTICAL, 550, California Avenue, suite 200,
PALO ALTO, CA 94306-1440, future member of the board of directors of the societe
anonyme COULTER PHARMACEUTICAL BELGIUM to be incorporated and which shall have
its registered office, Carnoy Building C 461, place Croix du Sud, 5 - 1538 -
LOUVAIN-LA-NEUVE.

Hereafter the "COMPANY",

                                    WHEREAS:

1.       The REGION has filed a belgian patent application n(Degree) 09400752 on
         August 19, 1994.

2.       The UNIVERSITY has filed a Belgian patent application n(Degree)
         09400751 on August 19, 1994.

3.       The REGION and UNIVERSITY have filed a P.C.T. patent application
         n(Degree) PCT/BE95/00076, on August 21, 1995, for the above mentioned
         patents and for the following countries: Kenya, Malawi, Soudan,
         Swaziland et Ouganda, Autriche, Belgique, Suisse + Liechtenstein,
         Allemagne, Danemark, Espagne, France, Grande-Bretagne, Grece, 

                                       1.
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         Irlande, Italie, Luxembourg, Monaco, Pays-Bas, Portugal, Suede,
         Burkina-Faso, Benin, Republique Centrafricaine, Congo, Cote d'Ivoire,
         Cameroun, Gabon, Guinee, Mali, Mauritanie, Niger, Senegal, Tchad, Togo,
         Armenie, Australie, Barbade, Bulgarie, Bresil, Belarus, Canada, Chine,
         Republique Tcheque, Estonie, Finlande, Georgie, Hongrie, Islande,
         Japon, Kenya Kirghizistan, Republique Populaire Democratique de Coree,
         Republique de Coree, Kazakhstan, Sri-Lanka, Liberia, Lituanie,
         Lettonie, Republique de Moldova, Madagascar, Mongolie, Mexique,
         Norvege, Nouvelle-Zelande, Pologne, Roumanie, Federation de Russie,
         Singapour, slovenie, Slovaquie, Tadjikistan, Turkmenistan, Trinite et
         Tobago, Ukraine, Etats-Unis d'Amerique, Ouzbekistan, Viet-nam et
         Republique de Macedoine.

4.       The COMPANY wishes to establish itself on the territory of the REGION
         WALLONNE to undertake the research and the manufacturing of SUPERLEUDOX
         and other products.

                  CONSEQUENTLY IT IS HEREBY AGREED AS FOLLOWS:

ARTICLE 1:        DEFINITIONS

In this agreement, the following words shall bear the following meanings:

1.1.     PATENTS:                   The patents applications n(Degree) 09400751
                                    and n(Degree) 09400752, filed respectively
                                    by the UNIVERSITY and the REGION.

1.2.     THE EXTENSION:             The PCT extension application for Belgian 
                                    patents n(Degree) 09400751 and 09400752,
                                    filed on August 21, 1995, with n(Degree)
                                    PCT/BE95/00076 for the countries mentioned
                                    in the 3rd point of the preamble of the
                                    present agreement.

1.3.     SUPERLEUDOX:               A "prodrogue" of the DOXORUBICINE which 
                                    requires, for a therapeutic and/or
                                    diagnostic application, the implementation
                                    of the PATENTS and the EXTENSION.

1.4.     OTHER PRODUCTS:            All antitumour "prodrogues", which 
                                    properties are initiated by cancerous cells
                                    and which requires, for therapeutic and/or
                                    diagnostic application, the implementation
                                    of the PATENTS and the EXTENSION.

1.5.     TURNOVER:                  Any gross receipt received by the COMPANY or
                                    by a sub-licensee less the reimbursements
                                    for returned goods, commercial discount, VAT
                                    and other taxes on sale and less
                                    commissions, insurance costs, freight 



                                       2.
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                                    and clearance charges, or any other costs
                                    directly linked to the sales taken into
                                    account.

1.6.     TRADE SECRETS:             All trade secrets, commercial know how and 
                                    similar information owned or controlled by
                                    the UNIVERSITY or the REGION pertaining to
                                    the PATENTS or to the EXTENSION or the
                                    production or sale of SUPERLEUDOX or the
                                    other PRODUCTS.

1.7.     PRE COMMERCIALIZATION:     Stage preceeding the commercialization of 
                                    SUPERLEUDOX and/or of the other products
                                    after release from laboratory and enabling
                                    to define the parameters to be taken into
                                    consideration for the manufacturing and
                                    commercialization of these products on a
                                    wide scale.

ARTICLE 2:  OWNERSHIP OF THE PATENTS

The REGION and the UNIVERSITY are the owners of the PATENTS and the EXTENSION
defined in articles 1.1 and 1.2..

No license has yet been granted on these PATENTS which are clear of any
security, pledge or charge whatsoever.

ARTICLE 3:  LICENSE

The REGION and the UNIVERSITY grant the company an exclusive world license to
produce, have produced, use and sell SUPERLEUDOX and other products.

This exclusivity can be opposed to the REGION and the UNIVERSITY.

The license applies to all the applications of the invention described in the
PATENTS and the EXTENSION which on the object of this contract and to the
applications implicitly connected with the PATENTS and the EXTENSION, on a
therapeutic as well as on a diagnostic level.

The REGION and the UNIVERSITY grant the COMPANY the exclusive use of the rights
deriving form the PATENTS and the EXTENSION, i.e., among others, trade secrets
mentioned in article 1.6, manufacturing secrets and results of the experiences
made during the elaboration of the PATENTS and the know-how related to them.

ARTICLE 4:  CONTRIBUTION, ASSIGNMENT AND SUBLICENSE

4.1.     The COMPANY shall refrain from bringing the license to a company or to
         substitute a third party in its rights and obligations or to undertake
         any assignment which would have the 

                                       3.
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         effect of transferring the whole of its rights and obligations to a
         third party, without previous consent of the REGION and the UNIVERSITY.

4.2.     The COMPANY is authorised to grant sub-licenses limited to the
         commercialization or pre-commercialization of SUPERLEUDOX and OTHER
         PRODUCTS.

4.3.     In the same way, the COMPANY shall be authorized to grant sub-licenses
         to subsidiaries or its parent company as long as this granting of
         sub-licenses does not infringe any provision of the present contract
         and that the company, benefiting from the sub-license, undertakes, in
         writing, to respect the entirety of the commitments contained in the
         present contract.

ARTICLE 5:  OBLIGATIONS OF THE COMPANY TOWARDS THE REGION

The COMPANY undertakes, towards the region, to respect the following
obligations:

5.1.     Operate or have operated, exclusively on the territory of the Region
         Wallonne (provinces du Brabant wallon, du Hainaut, de Liege, de
         Luxembourg et de Namur), the pre-clinical research and the clinical
         research related to SUPERLEUDOX and OTHER PRODUCTS, except if the
         company proves it impossible for technical and/or scientific reasons.

         Operate or have operated, exclusively on the territory of the REGION
         WALLONNE, the manufacturing of SUPERLEUDOX and other products.

         Within the limits here above described, the COMPANY undertakes to
         operate, on this territory, activities of a high technological level
         and to employ to this effect local workforce.

         The breach of these obligations entails the immediate payment, by the
         company to the region, of an amount equal to the difference between
         [     *    ] BEF and the total of the amounts already paid in 
         accordance with articles 5.2 or 5.3.

         The obligations described here above and at article 4, will come to an
         end as soon as the company pays the REGION an overall amount of
         [     *    ], as provided in articles 5.2 and 5.3.

5.2.     If the clinical tests on SUPERLEUDOX are positive, that is if a
         medicine for human use can be finalized, the COMPANY undertakes:

         5.2.1      to pay to the REGION the amount of [    *    ] BEF, after a
                    delay of five years calculated from the date the present
                    agreement becomes effective.

         5.2.2      to pay to the REGION annual royalties amounting to [ * ] of
                    the worldwide turnover pertaining to SUPERLEUDOX and other
                    PRODUCTS. These royalties are limited to a global amount of
                    [    *    ] BEF.

       * Certain confidential information contained in this document, marked by
         brackets, has been omitted and filed with the Securities and Exchange
         Commission pursuant to Rule 406 of the Securities Act of 1933, as
         amended.


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5.3.     If the clinical tests of SUPERLEUDOX cannot be realized or are
         negative, which means that a medicine for human use cannot be
         finalized, the COMPANY undertakes:

         5.3.1.     to pay to the REGION the amount of [     *    ] BEF, after 
                    a delay of five years calculated from the date the present
                    contract becomes effective.

         5.3.2.     to pay to the REGION annual royalties amounting to [*] of
                    the worldwide turnover pertaining to OTHER PRODUCTS. These
                    royalties are limited to a global amount of [     *     ] 
                    BEF.

5.4.     The COMPANY shall make the payment mentioned in articles 5.2.2. and
         5.3.2. after having received from the "Receveur Regional de la Region
         wallonne" an "invitation to pay".

         The latter is sent each year, two months after the end of the financial
         year of the COMPANY.

         The COMPANY has to pay within a delay of fifteen days after the sending
         by registered mail of the invitation to pay.

         Any delay in payment renders automatically the COMPANY debtor of an
         interest calculated on the legal rate increased by [ * ] per year, the
         maturity of payment constituting notice.

ARTICLE 6:  OBLIGATIONS OF THE COMPANY TOWARDS THE UNIVERSITY

The COMPANY undertakes, towards the UNIVERSITY, to respect the following
obligations:

6.1.     to finance the future pharmacological research and future pre-clinical
         tests pertaining to SUPERLEUDOX an OTHER PRODUCTS which should be
         realized by Lecturer A. TROUET.

         This obligation is submitted to the condition that a public aid on
         these activities be granted to the UNIVERSITY. Nevertheless, the
         present agreement does not form, in any way, a right to a public aid of
         the REGION towards the UNIVERSITY or towards the COMPANY.

6.2.     To pay to the UNIVERSITY annual royalties calculated on the turnover
         pertaining to SUPERLEUDOX and OTHER PRODUCTS:

         -        [ * ] on the turnover realized in Europe;

         -        [ * ] on the turnover realized in United States, Canada and 
                  Japan;

         -        a percentage to be defined in an agreement to be concluded
                  between the COMPANY and the UNIVERSITY for the turnover
                  realized elsewhere and which cannot exceed [ * ].

       * Certain confidential information contained in this document, marked by
         brackets, has been omitted and filed with the Securities and Exchange
         Commission pursuant to Rule 406 of the Securities Act of 1933, as
         amended.

                                       5.
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These royalties have to be paid on the following bank account: [*].

The UNIVERSITY and the COMPANY shall precise their contractual relations in a
separate document.

Nevertheless, the clauses of the present agreement shall prevail on any other
stipulation if there is no written agreement on an eventual derogation.

ARTICLE 7: MAINTENANCE OF THE PATENT

The COMPANY undertakes towards the REGION and the UNIVERSITY to respect the
following obligations:

7.1.     pay the annuities on the patents pertaining to SUPERLEUDOX and other
         PRODUCTS;

7.2.     pay the expenses related to the EXTENSION;

7.3.     do the necessary formalities for the maintenance of the patents and
         completion of the EXTENSION;

ARTICLE 8: PROTECTION OF THE PATENT

8.1      Each party will immediately inform the other parties of any
         infringement or breach by third parties to the PATENTS or the EXTENSION
         of which it would be informed.

         The REGION, the UNIVERSITY and the COMPANY will decide together of the
         judicial or extra judicial measures to be taken.

         In case of inaction of the REGION or the UNIVERSITY, the COMPANY may
         bring an action against the counterfeiter or any other proceeding
         judged necessary.

8.2      The UNIVERSITY and the REGION undertake to assist the COMPANY, among
         others, by informing the COMPANY of any element or information useful
         to reinforce its means of defense. They shall join, by way of voluntary
         intervention, the action brought by the COMPANY or shall take part in
         the negotiation if the COMPANY asks them to do so.

8.3      Any costs or fees payed during a procedure against the COMPANY or a
         negotiation, aiming to protect the PATENTS or the EXTENSION against any
         breach whatsoever, shall be borne by the COMPANY.

         The same shall apply to the costs linked to an eventual procedure of
         voluntary intervention requested by the COMPANY.

         Any damages obtained shall only benefit to the COMPANY.

         Any damages to be paid shall entirely be paid by the COMPANY.

* Certain confidential information contained in this document, marked by
  brackets, has been omitted and filed with the Securities and Exchange
  Commission pursuant to Rule 406 of the Securities Act of 1933, as amended.

                                       6.
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ARTICLE 9: GUARANTEE AGAINST THIRD PARTIES

9.1      The REGION and the UNIVERSITY guarantee the COMPANY that no
         counterfeiting action against the EXTENSION and the PATENTS is
         currently pending.

9.2      If the use of the PATENTS or the EXTENSION should lead the COMPANY or
         the sub-licencees to be sued as counterfeiters, the costs and fees
         exposed for their defense and the payment of eventual damages shall be
         borne by the COMPANY and the sub-licencees.

         The same shall apply to costs and fees linked to a counterclaim or a
         compromise, the sums eventually obtained in these last two cases shall
         only benefit to the COMPANY and the sub-licencees.

9.3      The COMPANY shall immediately inform the REGION and the UNIVERSITY of
         any lawsuit or notice filed against it and shall then give them the
         possibility to intervene in the dispute and/or in the lawsuit in which
         it would be implied for whatever reason.

9.4      The COMPANY shall be free - if no amicable settlement is found between
         the parties - to put an end to the contract if no judicial decision is
         rendered as long as two patent attorneys - one being chosen by the
         COMPANY and the other by the REGION and the UNIVERSITY - give a joint
         advice according to which the use of the PATENTS or the EXTENSION
         constitutes an infringement of the patent rights of a third party.

ARTICLE 10: IMPROVEMENTS

10.1.    The REGION and the UNIVERSITY undertake to communicate to the COMPANY
         and to put at its disposal any modification or improvement brought to
         the PATENTS or the EXTENSION during the length of the present
         agreement, without it resulting, for the COMPANY in an increase of the
         royalties and to grant, if need be, a license free of charge to the
         COMPANY.

10.2.    The modifications and improvements brought by the COMPANY do not
         require any authorization. The company shall, however, inform the
         UNIVERSITY and the REGION.

         If inventions of applications or improvements realised by the COMPANY
         are patentable and are, according to the applicable law, likely to be
         patented because they are sufficiently different from the PATENTS, the
         COMPANY shall patent them in accordance with the international
         conventions applicable in the field of patents.

         The COMPANY is under no obligation whatsoever to assign, neither in
         whole nor in part, to the UNIVERSITY or the REGION neither its rights
         pertaining to patents mentioned in the previous paragraph, nor its
         right to such patents.

         The COMPANY shall nevertheless grant the UNIVERSITY a non-exclusive
         licence on these patents, free of charge, in order to enable the latter
         to carry on its scientific research. 


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         The UNIVERSITY shall however refrain from publishing or evaluating the
         patents in a way that could harm the patents filed by the COMPANY.

10.3.    The parties will exchange the experience acquired through the research
         and the exploitation linked to the license and shall grant each other
         licenses for the inventions resulting from the improvements or from the
         application of the patents and the EXTENSION.

ARTICLE 11:  VERIFICATION OF THE ACCOUNTS

The COMPANY undertakes to keep special account books on which it mentions the
number and the prices of the sales linked to SUPERLEUDOX and OTHER PRODUCTS, as
well as any other indication of interest for the calculation of the royalties.

The REGION and the UNIVERSITY are authorized to have these account books
verified by a chartered accountant of their choice, approved by the COMPANY.

The detailed account of the royalties shall be drawn up yearly.

ARTICLE 12; REGISTRATION OF THE LICENSE

The REGION and the UNIVERSITY shall register the license and pay the costs
resulting form this registration.

ARTICLE 13: OBLIGATIONS OF THE REGION AND THE UNIVERSITY

13.1.    The REGION and the UNIVERSITY garantee:

         -        that the result of the PATENTS and the EXTENSION can be
                  obtained with the means and process described;

         -        the COMPANY against conception defects of the invention that
                  would make the PATENTS and the EXTENSION impossible to use;

         On the contrary, the REGION and the UNIVERSITY guarantee neither the
         result of the pre-clinical and clinical research nor the technical and
         commercial value of the PATENTS and the EXTENSION.

         The results and risks of the industrial and commercial exploitation of
         the results of the research are exclusively borne by the COMPANY.

13.2.    The REGION and the UNIVERSITY shall provide the COMPANY with any
         document and information necessary to use the PATENTS and the
         EXTENSION.

         They shall also provide the COMPANY with the technical assistance
         requested, the necessary and useful advise and shall transfer to it the
         know how linked to the PATENTS and the EXTENSION.

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ARTICLE 14:  LENGTH OF THE AGREEMENT

The present agreement shall only come into force when the suspensive condition
mentioned in article 15 is completed.

The agreement shall terminate after the expiration of the protection of the
PATENTS, the EXTENSION and the patents filed in application of article 10 of the
present contract.

ARTICLE 15:  SUSPENSIVE CONDITION

The present agreement is submitted to the following suspensive condition:

         - incorporation of a Belgian societe anonyme, subsidiary of the
         American company COULTER PHARMACEUTICAL. This incorporation depends on
         investments to be made by third parties to COULTER PHARMACEUTICAL.

If this condition is not fulfilled within three months of the signature of the
present agreement, the latter shall be considered as void and non existent,
without any costs for the parties.

ARTICLE 16:  TERMINATION

16.1.    The present agreement is automatically terminated and without prior
         notice in case of bankruptcy, liquidation or bankrupt's certificate.

16.2.    The present agreement can also be terminated by the REGION or the
         UNIVERSITY in case of non commercialization of the licence by the
         COMPANY or insufficient commercialization, after a first
         commercialization.

         By non commercialization of the license is meant: stoppage of all
         pre-clinical or clinical research related to SUPERLEUDOX and other
         products except if this research has been brought to an end and that
         the commercialization of the products is about to be set up.

         By insufficient commercialization is meant: a commercialisation which,
         during the first five years following the beginning of the
         commercialization of SUPERLEUDOX or other products, would give rise to
         payments of amounts inferior to [    *    ] BEF, for the royalties
         provided for in points 5.2 and 5.3 to be paid to the REGION and to the
         payment of amounts inferior to [    *    ] BEF for royalties provided 
         for in point 6.2, to be paid to the UNIVERSITY. This termination does
         not give, in any case, a right to reimbursement of the amounts already
         paid by the COMPANY.

16.3.    The COMPANY can terminate the present agreement by sending a registered
         mail if the PATENT or the EXTENSION are not granted, are declared void
         or depend on a previous invention already patented.

         The royalties already paid nevertheless remain the property of the
         REGION and the UNIVERSITY.

       * Certain confidential information contained in this document, marked by
         brackets, has been omitted and filed with the Securities and Exchange
         Commission pursuant to Rule 406 of the Securities Act of 1933, as
         amended.

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16.4.    After an end has been put to the present agreement, the REGION and the
         UNIVERSITY are free to grant to anyone a license relating to the
         PATENTS and the EXTENSION.

ARTICLE 17:  NOTICES

Any mail exchanged within the framework of the present agreement is to be sent:

         -        For the REGION:

DIRECTION GENERALE DES TECHNOLOGIES, DE LA RECHERCHE ET DE L'ENERGIE
Avenue Prince de LIEGE, 7,
5100              JAMBES.

         -        For the UNIVERSITY:

UNIVERSITE CATHOLIQUE DE LOUVAIN
Place de l'Universite, 1,
1348              LOUVAIN-LA-NEUVE.

         -        For the COMPANY:

COULTER PHARMACEUTICAL, 550 California Avenue, suite 200, PALO ALTO-CA
94306-1440 and as soon as the company is incorporated, to its registered office.

ARTICLE 18:  CONFIDENTIALITY

The parties undertake to maintain confidential any information or document
exchanged during the present agreement and this for the whole duration of the
agreement.

ARTICLE 19:  ENTIRE AGREEMENT

The present agreement constitutes the entire agreement between the parties.

It supersedes and cancels all previous undertakings, written or verbal
agreements having the same object.

It cannot be modified except by a written agreement signed by the parties.

ARTICLE 20:  INVALIDITY

Any article of the present agreement that threatens public order or infringes a
mandatory statute or regulation shall be considered as non written. Its nullity
shall however not affect the validity of the agreement as a whole.

On the contrary, the parties shall endeavour to replace the void article by a
clause with equivalent economical effect.

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ARTICLE 21:  DISPUTES

This agreement shall be governed by the laws of Belgium.

Any claim arising from or in connection with this agreement shall be submitted
to the exclusive jurisdiction of the Courts of Brussels.



Signed on ... (date), in ... (place), in six copies.



                                 POUR LA REGION

                           Menslem Jean-Pierre GRAFE,
            Ministre de la Recherche, du Developpement technologique,
                    du Sport et des Relations internationales



                                POUR L'UNIVERSITE



Monsieur Marcel CROCHET                                    Monsieur Andre TROUET
Recteur                                                               Professeur


                                POUR L'ENTREPRISE

                              Dr. Arnold L. ORONSKY
             future member of the board of directors of the company

       * Signatures are found on the French version of this Agreement,
         dated March 15, 1996.

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I, William G. Harris, hereby certify that the above Exhibit is a fair and
accurate French to English translation.



                                              /s/ WILLIAM G. HARRIS
                                     ------------------------------------------
                                                  William G. Harris
                                     Vice President and Chief Financial Officer



December 23, 1996



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