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                                                                    EXHIBIT 10.7

CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY WITH
THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO THE
OMITTED PORTION.

July 26, 1993

                           EXCLUSIVE LICENSE AGREEMENT
               GOPAL M. NAIR AND BIONUMERIK PHARMACEUTICALS, INC.
                                       FOR
                            MDAM, MEDAM, AND ANALOGS

         WHEREAS, Gopal M. Nair, Ph.D. ("Nair") has invented, patented, and owns
the exclusive proprietary rights to the compounds MEDAM, MDAM, and certain
related anti-folate compounds, identified by United States Patent Office Numbers
4,996,207; 5,073,554, serial # 07/882,484; Japan 4-505932; Europe 91902932-2
(PCT/US/00220) (collectively, the "Compounds"); and

         WHEREAS, Nair desires to grant an exclusive, world-wide license to
BioNumerik Pharmaceuticals, Inc. ("BNP") to formulate, market, manufacture and
use the Compounds and all patent rights, technology and know-how related to the
Compounds in all therapeutic areas of potential use in consideration of the
receipt by Nair of options to purchase Common Stock of BNP and certain royalty
payments in the manner provided herein. In addition, BNP wishes to provide
certain specified funding for continued research and development of the
Compounds by Nair and the conduct by BNP of pre-clinical experimentation and
development of the Compounds with a view to the filing of applications to
initiate human clinical trials thereof in the United States;

         NOW, THEREFORE, in consideration of the premises and the mutual
obligations of the parties, Nair and BNP hereby agree as follows:

         1.       Grant of License

         Nair, for good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, hereby grants to BNP an exclusive world-wide
license to formulate, market, manufacture and use the Compounds (and all
products containing the Compounds) and all patent rights, technology, know how
and other proprietary rights to the Compounds or any such products in all
therapeutic areas of potential use. The foregoing license by Nair is made in
consideration of (i) the issuance to Nair of options to purchase [**] shares of
common stock, par value 0.01 per share ("Common Stock") of BNP upon the
execution hereof and BNP's agreement to issue Stock Options to purchase an
additional [**] shares of such Common Stock on each of the three anniversary
dates hereof thereafter such that the total number of shares for which Nair
shall be issued Stock Options to acquire is equal to 212,948 shares of Common
Stock ([**]) and (ii) the retention of a royalty by Nair in the manner set forth
below on all of BNP's world-wide commercial sales of the Compounds, or of any
proprietary pharmaceutical products that contain any of the Compounds (the
"Products") until the expiration of all U.S. and foreign patents on the
Compounds. The amount of such royalty will be based on annual sales world-wide
from such Product(s) expressed in U.S. dollars, in accordance with the following
schedule:

[**] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

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<TABLE>
<CAPTION>
         Annual Products Sales                 Royalty in Percent
         in U.S. Dollars                       of Annual Sales
<S>                                            <C>
         [**]                                  [**]
         [**]                                  [**]
         [**]                                  [**]
</TABLE>

         Higher royalty percentages in the above schedule will only be paid on
that portion of sales which exceeds the threshold amount. For Products which are
covered by more than one patent, only a single royalty will apply with respect
to annual sales of such Product. In countries or territories where Patent Rights
(patent applications or patents) exist, the earned royalty shall be payable
until expiration of such Patent Rights. In those countries or territories where
there are no patent rights in existence regarding the technology the earned
royalty shall be payable for ten (10) years after the first commercial sale or
other disposal for profit. In the event BNP sub licenses the Compounds (or
Products) to a third party, BNP shall pay Nair [**] of any initial or one-time
assignment or licensing fee and up front payments actually received by BNP
during the first year following the execution of this Agreement or [**] thereof
during the second year thereafter or [**] thereof during the third year
thereafter or [**] thereof during the fourth or subsequent years, as long as
this agreement remains in effect. These benefits are in addition to the royalty
payments to Nair according to the above schedule. The exercise price of the
Stock Options granted to Nair pursuant to this Section I is [**] per share of
Common Stock and all options shall vest upon their issuance and be exercisable
for a period of [**] years after the date of their issuance.

         2.       Pre-clinical Experimentation.

         BNP will provide certain funding and resources with respect to the
Compounds pursuant to that certain Consulting and Research Agreement (the
"Research Agreement") between BNP and Nair attached hereto as Exhibit A. The
goal of the work conducted under the Research Agreement will be to obtain
sufficient data embodied in a Master Drug File to permit the filing of one or
more Investigational New Drug ("IND") applications with the Food and Drug
Administration to commence human clinical trials on one or more of the Compounds
in the United States. BNP and Nair further agree that certain laboratory
experiments will be conducted from time to time as BNP sees fit in Nair's
laboratory under separate special contract with BNP or in BNP laboratories in
accordance with FDA Good Laboratory Practices (GLP) standards when necessary.
BNP and Nair also agree that in certain instances it may be necessary to
contract with third parties, using BNP funds, for specialized experimentation
from time to time as BNP sees fit, for the purpose of obtaining information
relevant to filing an IND application with the FDA. During the course of any
such pre-clinical experimentation in his laboratory, Nair is expected to
continue independent research activities at his own expense and the generation
of new intellectual property in the anti-folate area with the agreement that
during the term of the Research Agreement or any other research contracts in
effect between BNP and Nair, BNP will receive an exclusive first right to
license any new intellectual property that is not already covered by this
Agreement, the terms of which license will be negotiated in good faith by both
parties at an appropriate time in the future.

[**] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

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         3.       Clinical Trials and Marketing.

         Following the submission of one or more IND applications to the United
States FDA with respect to any of the Compounds or their congeners, BNP will be
responsible for endeavoring to establish a means to conduct human clinical
trials in accordance with applicable FDA requirements under Good Clinical
Practices (GCP) guidelines. Nair and BNP agree that BNP will be responsible for
the determination of the starting dose of the drug in humans, based on pre
clinical pharmacology studies, and further that BNP will be responsible for the
writing of two or more Phase I protocols for human testing which will involve at
least 25 patients and two different schedules of drug administration. Nair and
BNP agree further that BNP will, if BNP sees fit, pursue relevant Phase II
clinical trials in humans based on observations made from data accrual from the
Phase I studies and additional pre clinical data in order to perform Phase II
trials in certain of the human cancer areas in which the Compound appears to
have the most efficacy. Funding for the Phase I, Phase II, or Phase III clinical
trials may be provided by BNP, if BNP's financial condition permits and with
explicit approval by the Board of Directors of BNP for each Phase of clinical
testing. In the event approval by the Board of Directors does not occur, BNP
will seek to enter into a cross-licensing agreement with another pharmaceutical
company who is capable of completing clinical trials of the Compound. In the
event of FDA approval of a New Drug Application (NDA) covering one or more of
the Compounds, BNP, in accordance with the exclusive license granted in Section
1, will have the exclusive right to formulate, market, manufacture, and use any
NDA approved pharmaceutical products relating to such Compounds on a world-wide
basis. It is understood that the conduct of clinical trials and marketing
activities may occur either independently by BNP or pursuant to a licensing
agreement between BNP and a pharmaceutical industry partner.

         4.       Additional Consideration.

         In addition to the consideration provided to Nair pursuant to Section
1, upon the approval of an IND covering one or more of the Compounds, Nair will
receive a one-time grant of Stock Options to purchase an additional [**] shares
of Common Stock of BNP. The exercise price of such Stock Options shall be [**]
per share of Common Stock and such options shall vest upon their issuance and be
exercisable for a period of [**] years after the date of their issuance. BNP
shall also hire Dr. Nair to provide consulting services to BNP pursuant to the
Research Agreement, a copy of which is attached hereto as Exhibit A.

         5.       BNP Funded Contract Research in Nair's Laboratory.

         BNP and Nair have agreed to enter into the Research Agreement in order
to provide for pre clinical development and discovery of the Compounds, with BNP
funding the actual research costs plus not more than 25% overhead to Nair's
laboratory pursuant to an agreed upon written plan for the purpose of completing
necessary studies pertaining to the continued discovery, reduction to practice,
patent filing and maintenance, for the development of these and other discovered
Compounds.

         6.       Confidentiality.

         Nair and BNP agree to maintain the confidentiality of all research
results and any new unpatented intellectual property relating to the Compounds
or Products and to use any such research results and intellectual property in
accordance with the terms of this Agreement.

         7.       Reporting of Research Results and Publication Rights.

                  a. To keep BNP informed on the progress of the funded contract
         research under the Research Agreement, Nair shall submit brief written
         progress reports to BNP on a quarterly basis. In addition, BNP
         scientists will be given reasonable access to Nair and his technical
         laboratory scientists on an informal basis to discuss the progress made
         in any given research project or program conducted pursuant to the
         Research Agreement.

[**] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

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                  b. Nair and BNP scientists shall have rights to publish the
         results of the research conducted pursuant to the Research Agreement
         (the "Funded Research") equivalent to rights normally associated with
         academic research, subject, in all cases, to prepublication review and
         consent (which consent will not be unreasonably withheld) by BNP; and
         Nair and BNP agree further to delay in publication when necessary to
         permit patent applications to be filed where potentially patentable
         inventions are identified.

         8.       Patents and Inventions

                  a. The parties shall work together to identify additional
         discoveries and inventions ("New Inventions") that both (i) result from
         the research conducted under the Research Agreement and (ii) are in
         addition to the Compounds (and all Products, patent rights, technology,
         and know-how related thereto). The inventors of any New Invention shall
         be responsible for drafting, filing, and prosecuting all patent
         applications relating to New Inventions with the assistance from a
         patent attorney or patent agent as appropriate (US and foreign), where
         such New Inventions result from the Funded Research and inventorship
         resides either solely with Nair or employees of Nair or solely with BNP
         or employees of BNP. In the event New Inventions arise from the Funded
         Research where employees of BNP and employees of Nair are jointly named
         as inventors, the parties shall agree on which of the parties will
         handle the drafting, filing, and prosecution activities. In cases where
         Nair handles the patent drafting, filing, and prosecution activities,
         BNP shall be given an opportunity to review and provide input into the
         content of the first filed application and shall be kept informed as to
         the progress of the patenting activity (provided BNP exercises its
         option for an exclusive license as set forth in Section 10 below).

                  b. BNP shall receive exclusive assignment and be the owner of
         all patent applications, patents, and other intellectual property
         rights with respect to New Inventions where inventorship of a New
         Invention resides solely in BNP or employees of BNP. Patents, patent
         applications and other intellectual property rights relating to New
         Inventions which name, as joint inventors, one or more employees of BNP
         with one or more employees of Nair or Nair shall be jointly assigned to
         BNP and Nair with each party taking a one half undivided ownership
         interest in such patents, patent applications, and other intellectual
         property rights relating thereto. Neither party will use or license
         patents or other intellectual property rights which are jointly
         assigned to Nair and BNP without first entering into an agreement with
         the other party. The parties agree that all patents, patent
         applications and other intellectual property rights relating to New
         Inventions that are owned by Nair or jointly owned by Nair and BNP
         shall be subject to the exclusive option in Section 10 hereof.

         9.       Representation and Warranties.

         Nair hereby represents and warrants to BNP that (i) Nair is the
exclusive owner of the Compounds and all patent rights, trade secrets and other
proprietary rights relating to the Compounds as of the date of this Agreement,
(ii) that Nair has the right to license to BNP the Compounds and all patent
rights, trade secrets and other proprietary rights relating thereto on a sole
and exclusive basis and (iii) the use by BNP of the Compounds and the patent
rights, trade secrets and other proprietary rights relating thereto will not
violate the rights of any third parties. Nair further represents and warrants
that, immediately prior to the execution of this Agreement, Nair had good and
indefeasible title to the Compounds and the patent rights, technology, and
know-how related thereto free and clear of all liens, mortgages, pledges,
claims, charges, options, defects, requirements for consent to assignment or
other encumbrance of any kind. Nair shall indemnify and hold BNP harmless from
and against any costs, losses, damages, or other liabilities suffered or
incurred by BNP with respect to or as a result of the breach of any of the
foregoing representations and warranties of Nair contained herein. In addition,
to the extent Nair does not indemnify BNP for any such costs, losses, damages,
or other liabilities, BNP shall be entitled to offset such costs, losses,
damages or other liabilities against any royalties or other amounts to be paid
to Nair pursuant to this Agreement.

         10.      Exclusive Option

                  a. BNP is hereby granted a limited term, exclusive option to
         obtain an exclusive license for any New Inventions owned by Nair or
         owned jointly by BNP and Nair which result from the Funded Research
         under the Research Agreement. The exclusive license would include the
         right to sub license as

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         well as the right to make, have made, use and sell the New Inventions
         and any products relating thereto and would extend world-wide, provided
         certain diligence requirements are met as described in (e) below. The
         exclusive option shall include the right to exclusively license both
         New Inventions owned solely by Nair as well as Nair's interest in any
         New Inventions resulting from joint inventions of BNP and Nair.
         Further, the technology covered by the exclusive option also includes
         all technology derived from all ongoing discovery research in Nair's
         Laboratory at the time of execution of this Agreement provided BNP's
         base funding commitment covers any continuation of the research project
         or program in question and the research project or program in question
         is not the subject of a pre-existing commitment to a third party (other
         than governmental commitments which results from government grants).

                  b. In the case where the New Invention in question involves
         patent rights (patent applications or patents) then all know how, trade
         secrets and proprietary data and information associated with the patent
         rights would be included with the patent rights under a single exercise
         of the exclusive option. Where the option is for New Inventions that do
         not involve patent rights, the option would be available only to the
         extent a trade secret or know how license providing commercial
         exclusivity to the holder of the option could be granted while
         preserving the scientist's right to publish the results of the research
         work.

                  c. The term of the exclusive option granted to BNP pursuant to
         this Section 10 shall extend from the time the first patent application
         describing and claiming the product or technology in question is filed
         (or any unpatentable New Invention is otherwise first identified as
         such in writing to BNP) until the end of Phase I Trials on the product
         or technology in question ["Phase I Trials" being defined as clinical
         trials based on an IND (or equivalent) filing involving at least 25
         patients], provided BNP commits to fund and carry out the development
         work (toxicology, GMP manufacturing, etc.) reasonably necessary to
         progress the product or technology in question through Phase I Trials
         in accordance with a development plan which is acceptable to Nair
         (which acceptance shall not be unreasonably withheld). To the extent
         possible, the development work shall be carried out by Nair under
         contract with BNP and the costs for such development work shall not be
         part of, or offset against, BNP's obligations for Research Funding
         under the Research Agreement. In addition, as part of the development
         cost funding commitment, BNP shall pay all of Nair's documented and
         reasonable patent filing and prosecution costs for any patent
         application covering the new product or technology in question, as such
         costs are incurred by Nair. In the event BNP elects not to continue
         funding of the development work or patent costs on a particular product
         or technology subject to the exclusive option granted pursuant to this
         Section 10 of the Agreement, BNP's exclusive option for an exclusive
         license to such particular product or technology shall expire and Nair
         shall have the right to exploit those commercial rights owned by Nair
         to the specific product or technology, itself, or through one or more
         commercial partners. BNP, however, shall retain an exclusive option on
         all other products and technology subject to the exclusive option.

                  d. Upon exercise of the exclusive option BNP shall have the
         right to designate those foreign countries in which patent filings are
         desired and Nair shall effect such filings provided BNP gives Nair its
         foreign filing instructions at least 3 months before the end of the
         Convention Year and agrees to pay all patent prosecution costs (see
         below).

                  e.       Diligence

                           BNP shall use reasonable efforts to diligently
                  proceed with the development, manufacture and
                  commercialization of products, processes, methods, and/or
                  technologies exclusively licensed from Nair pursuant to
                  exercise of the option and shall endeavor to market the same
                  within a reasonable time after the execution date of the
                  exclusive license in question in amounts sufficient to meet
                  the market demand thereof. In this regard BNP shall commit to
                  develop the licensed product or technology in accordance with
                  a development plan which is submitted to BNP's Board of
                  Directors for approval (which approval shall not be
                  unreasonably withheld) and Nair and BNP shall reciprocally
                  provide each other with annual written reports demonstrating
                  good faith efforts to meet the requirements of the development
                  plan as well as the above general diligence requirement
                  beginning with the year in which the exclusive license is
                  executed. In addition to the

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                  above general diligence requirement, BNP shall meet the
                  following benchmarks to maintain the exclusive license granted
                  by Nair:

         1) BNP and/or its sub licensees shall submit a request to initiate
clinical trials necessary for government approval of a product, process, method
or technology exclusively licensed from Nair within 4 years after the execution
date of the license in at least one country in each of the Major Marketing
Regions of the world (defined as North America, Europe and the Pacific Basin).

         2) BNP and/or its sub licensees shall submit a request for government
approval (equivalent to a U.S. NDA or PLA) to initiate commercial sales of a
product, process, method or technology exclusively licensed from Nair within 8
years after the execution date of the license in at least one country in any one
of the Major Marketing Regions of the world.

         3) BNP and/or its sub licensees shall initiate commercial sales of any
product, process, method, or technology for which government marketing approval
is obtained pursuant to 1) or 2) above within [**] of obtaining such approval
and, following such initiation of commercial sales will continuously attempt to
commercially market such product, process, method, or technology during the
remaining term of the license.

         Failure to meet the diligence benchmarks set forth in subparagraphs 2
and 3 will result in termination of the license on a world-wide basis with
respect to each product for which such benchmarks have not been met, whereas
failure to meet the diligence benchmarks set forth in subparagraph 1) above will
result in termination of the license in those Major Marketing Regions of the
world where the benchmark is not met.

         (i)      product liability

         BNP shall indemnify, defend and hold Nair harmless against any claim or
liability resulting from BNP's use of the Compounds. Further, at the time of
marketing any Compounds or Products, BNP shall carry product liability insurance
consistent with industry standards and Nair shall have the right to be named as
a co-insured under any such insurance policy.

         (ii)     payment of patent prosecution costs

         BNP shall reimburse Nair for any of its reasonable and documented costs
in drafting, filing, and prosecution of new US patent application(s) not
previously paid by Nair at the time the exclusive license is granted pursuant to
exercise of the exclusive option and shall reimburse Nair for all additional
foreign filing and prosecution costs and any additional US patent prosecution
costs as such costs are incurred during the terms of the license. Patent
maintenance fees shall be part of reimbursable patent prosecution costs. All
cost reimbursements shall be fully creditable against future earned royalties,
and BNP shall have the right to recover all such cost reimbursements out of (and
to deduct all such cost reimbursements from) the amount of any royalties to be
paid to Nair.

         (iii)    right of first refusal for product manufacture

         BNP shall have the right of first refusal to manufacture up to 100% of
any product containing the Compounds exclusively licensed pursuant to Section 1
hereof, and any exclusive license granted pursuant to the exclusive option
provided by this Section 10, provided that the price quoted for such
manufactured product is reasonable and competitive in the marketplace.

[**] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

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         (iv)     other provisions

         Any exclusive license agreement granted pursuant to exercise of the
exclusive option provided by this Section 10 shall include other customary and
standard provisions including Accounting and Reports of Royalty, Waiver,
Infringement, Termination, Force Majeure, Assignability, Notices, Governing Laws
(State of Texas) and the like.

         11.      Term and Terminations.

         Unless earlier terminated as herein provided, the license granted to
BNP hereunder and the other rights and obligations of this Agreement shall
extend until the later to occur of (a) the expiration of the last to expire
patent issued on any Compound and (b) seventeen years after the date of this
Agreement. BNP's obligation to fund research to be conducted by Nair under the
Research Agreement, shall extend for a term of four (4) years after the date
hereof provided that it may be extended for additional one year terms thereafter
by the mutual agreement of the parties. This Agreement may be terminated by BNP
at any time prior to the expiration of its term upon notice in writing to Nair
not less than one year prior to the date of such proposed termination. In the
event of termination of this Agreement by BNP prior to the expiration of its
term, BNP shall have no further obligations to Nair hereunder, and unless the
rights to such Compounds, and other proprietary rights related thereto have
already been conveyed to BNP, in accordance herewith, the proprietary rights to
the Compounds, and other proprietary rights licensed to BNP pursuant to Section
1 hereof, shall revert to Nair. Notwithstanding the foregoing, in the event the
Compounds and related proprietary rights are conveyed to BNP in accordance with
Section 14 hereof, BNP shall continue to own such Compounds and related
proprietary rights whether or not this Agreement is terminated.

         12.      GOVERNING LAW:

         THIS AGREEMENT IS ENTERED INTO AND SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS, WITHOUT REGARD TO THE
CONFLICT OF LAW PRINCIPLES THEREOF.

         13.      BNP Business Information:

         Nair recognizes and agrees that the options to purchase Common Stock
issued and to be issued to Nair in connection with this Agreement (and the
Common Stock to be issued upon the exercise of such options) are restricted and
have not been registered under the Securities Act of 1933 or any other state or
federal securities laws and that the stock to be received by Nair upon exercise
of such options must be held for an indefinite period of time unless the sale or
transfer of such stock is registered under the applicable securities laws or
transferred pursuant to an exemption therefrom. Nair recognizes and agrees that
the success of BNP's business is speculative and depends upon a number of
factors beyond the control of BNP. BNP makes no representation or warranty as to
the potential success of its business. Nair acknowledges that he has entered
into this Agreement after making an independent investigation of BNP's
operations, and not upon any representations with respect to future sales or
royalties or any other representation which is not expressly set forth herein.
No warranties, express or implied are made by BNP in connection with this
Agreement.

         14.      Conveyance of Compounds

         In the event that (i) this Agreement is still in effect on the fourth
anniversary hereof and (ii) BNP has complied with all of its obligations under
the Research Agreement, then Nair shall within 5 days of such anniversary,
without receipt of any additional consideration from BNP, convey to BNP the
entire and exclusive worldwide right, title and interest in and to the Compounds
and also convey to BNP all patent rights, technology and know-how related to the
Compounds in all therapeutic areas of potential use. The conveyance of the
Compounds and other rights as provided above shall be subject only to the
existing rights if any, of any United States governmental entity to use the
compounds or related technology for the limited purposes to which such entity
may be entitled. Nair agrees to take any and all actions in connection with such
conveyance as may be necessary to more fully vest in BNP the exclusive rights to
all such Compounds and technology. Following the conveyance of such

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Compounds and technology, BNP shall indemnify Nair from and against any claims
by any U.S. governmental entity with respect to BNP's use of such Compounds and
technology. In addition, Nair shall indemnify BNP from and against any claims by
any other party with respect to BNP's ownership of and right to use any such
Compounds or technology.

         15.      Further Assurances.

         Nair hereby covenants and agrees with BNP, and its successors and
assigns, that Nair and his executors and administrators, shall and will do all
lawful acts and things, and make, execute and deliver any and all other
instruments in writing, and any and all further applications, papers,
affidavits, assignments, and other documents, in the United States and all
foreign countries, which, in the opinion of counsel for BNP, may be required or
necessary more effectively to secure to and vest in BNP, its successors and
assigns, the rights granted hereunder.

         Each party to this Agreement has had the opportunity to review this
Agreement with its legal counsel. This Agreement shall not be construed or
interpreted against any party on the basis that such party drafted or authored a
particular provision, parts of or the entirety of this Agreement.

         IN WITNESS WHEREOF, the parties have executed this Agreement on this
third of August, 1993.

                                             /s/ Madhavan G. Nair
                                             Gopal M. Nair, Ph.D.

                           BIONUMERIK PHARMACEUTICALS, INC.

                                             By: /s/ Frederick H. Hausheer
                                                 Frederick H. Hausheer, M.D.
                                                 Chief Executive Officer

                                       8<PAGE>   1
                                                                   EXHIBIT 10.8

CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY WITH
THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO THE
OMITTED PORTION.

                                                                    Confidential

                    Amendment to Exclusive License Agreement

This letter agreement is being entered into for the purpose of amending that
certain Exclusive License Agreement ( the "License Agreement"), executed as of
August 3, 1993, between Gopal M. Nair, Ph.D. and BioNumerik Pharmaceuticals,
Inc. ("BNP").

In consideration of the foregoing and for other good and valuable consideration,
the receipt and sufficiency of which is hereby acknowledged, the parties hereby
agree as follows:

         1. Section 10.e.1) of the License Agreement is hereby amended so that
such section, as amended, will read in its entirety as follows:

         "BNP and/or its sublicensee(s) shall submit a request to initiate
         clinical trials (i.e. a U.S. IND application) necessary for government
         approval of a product, process, method or technology exclusively
         licensed from Nair within [**] after the execution date of the license
         in at least one country in North America."

         2. Section 1 of the License Agreement is hereby amended by (A) deleting
the fifth and sixth sentences of the third paragraph of Section 1 of the License
Agreement (which sentences begin with the language "In the event BNP sub
licenses..." and end with the language " .... to Nair according to the above
schedule") and (B) replacing such fifth and sixth sentences with new language
which shall read in its entirety as follows:

         "BNP shall have the right, following notice to Nair, to sublicense all
         or part of its rights to the Compounds (and/or all or part of its
         rights to products containing the Compounds and all other patent rights
         and other proprietary rights licensed under this Agreement ) to a third
         party or parties. In such event, BNP shall pay Nair [**]% of any
         up-front sublicensing payment amount that BNP receives from such
         sublicensee(s) and [**]% of all royalty and other payments that BNP
         receives from such sublicensee(s). Any sublicenses granted by BNP shall
         continue in full force and effect so long as Nair receives the
         sublicense payment amounts provided for above. Sales of Compounds
         and/or Products or other technology by sublicensees of BNP will not be
         subject to the royalty amounts on annual sales referred to in the first
         two paragraphs of this Section l ."

         [**] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED
SEPARATELY WITH THE COMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH
RESPECT TO THE OMITTED PORTIONS.

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         3. All capitalized terms used in this letter agreement shall have the
same meaning as assigned to such terms in the License Agreement. Each party
hereto agrees to take such further actions and to sign such additional documents
as may be requested by the other party in order to further evidence or reflect
the intent of this agreement.

Except as amended hereby, all other terms and provisions of the License
Agreement will remain in full force and effect and continue in accordance with
their terms.

In Witness Whereof, the parties have executed this agreement as of August 23,
1996.

                                    BioNumerik Pharmaceuticals, Inc.

/s/ Madhavan G. Nair                By:      /s/ Frederick H. Hausheer
Gopal M. Nair, Ph.D.                         Frederick H. Hausheer M.D.
                                             Chairman and
                                             Chief Executive Officer

                                       2
<PAGE>   3
                                                                    CONFIDENTIAL

                    AMENDMENT TO EXCLUSIVE LICENSE AGREEMENT

This amendment is being entered into for the purpose of amending that certain
Exclusive License Agreement between Gopal M. Nair, Ph.D. and BioNumerik
Pharmaceuticals, Inc. ("BNP"), executed as of August 3, 1993 and amended as of
August 23, 1996 (the "License Agreement").

In consideration of the foregoing and for other good and valuable consideration,
the receipt and sufficiency of which are hereby acknowledged, the parties hereby
agree as follows:

         1. Section 10.e.2) of the License Agreement is hereby amended so that
such section, as amended, will read in its entirety as follows:

                  "BNP and/or its sublicensee(s) shall submit a request for
                  government approval (equivalent to a U.S. NDA or PLA) to
                  initiate commercial sales of a product, process, method or
                  technology exclusively licensed from Nair within 10 years
                  after the execution date of the license in at least one
                  country in any one of the Major Marketing Regions of the
                  World."

         2. All capitalized terms used in this amendment shall have the same
meaning as assigned to such terms in the License Agreement. Each party hereto
agrees to take such further actions and to sign such additional documents as may
be requested by the other party in order to further evidence or reflect the
intent of this agreement.

Except as amended hereby, all other terms and provisions of the License
Agreement will remain in full force and effect and continue in accordance with
their terms.

In Witness Whereof, the parties have executed this amendment as of the dates
indicated below.

                                            BioNumerik Pharmaceuticals, Inc.

/s/ Madhavan G. Nair                        /s/ Frederick H. Hausheer
Gopal M. Nair, Ph.D.                        Frederick H. Hausheer, M.D.
                                            Chairman and Chief Executive Officer

Nov. 19, 1998                               11/23/98
Date                                        Date

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