Document:

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                                                                   EXHIBIT 10.61

                                                                  EXECUTION COPY

                           RIGHTS REVERSION AGREEMENT

         This RIGHTS REVERSION AGREEMENT (the "Agreement") is dated as of
October 23, 2000, by and between AVENTIS PHARMACEUTICALS PRODUCTS INC., a
Delaware corporation with its principal office at Route 202-206, Bridgewater,
New Jersey 08807, formerly known as Rhone-Poulenc Rorer Pharmaceuticals Inc.
("APPI"), and RHONE-POULENC RORER INC., a Pennsylvania corporation with its
principal office at 500 Arcola Road, Collegeville, Pennsylvania 19426 ("RPR
Inc.") on the one hand, and GPI POLYMER HOLDINGS, INC. (formerly named GPI
Holdings, Inc.), a Delaware corporation with its principal office at 222
Delaware Avenue, P.O. Box 2306, Wilmington, Delaware 19899 ("GPI Holdings"), and
GUILFORD PHARMACEUTICALS INC., a Delaware corporation with its principal office
at 6611 Tributary Street, Baltimore, Maryland 21224 ("GPI"), on the other hand.

                                    RECITALS

         WHEREAS, APPI, GPI Holdings and GPI are parties to that certain
Marketing, Sales and Distribution Rights Agreement dated as of June 13, 1996, as
amended on September 25, 1998 (the "Marketing Rights Agreement"), pursuant to
which APPI, on the one hand, and GPI Holdings and GPI (collectively,
"Guilford"), on the other hand, entered into a strategic alliance whereby, among
other things:

                  (i)      GPI Holdings granted APPI the exclusive right
         throughout the Territory (as defined in the Marketing Rights Agreement)
         to market, advertise, promote, sell and distribute the Product (as
         defined in the Marketing Rights Agreement) for use in the Field (as
         defined in the Marketing Rights Agreement);

                  (ii)     GPI agreed to assign APPI the New Drug Application
         for the GLIADEL Product (as defined in the Marketing Rights Agreement)
         if and when approved by the FDA;

                  (iii)    APPI agreed to use commercially reasonable efforts to
         obtain Regulatory Approval (as defined in the Marketing Rights
         Agreement) for the GLIADEL Product throughout the Territory for use in
         the Field and if, as and when obtained, to market, advertise, sell and
         distribute the GLIADEL Product throughout the Territory for use in the
         Field;

                  (iv)     GPI agreed to manufacture and supply the Product (as
         defined in the Marketing Rights Agreement) to APPI pursuant to the 1996
         Manufacturing and Supply Agreement (as defined below);

                  (v)      Guilford and APPI agreed to collaborate on the
         development of certain further PCPP:SA/BCNU products for use in the
         Field, including products with BCNU doses higher than 3.85%, all of
         which were to be included within the grant of exclusive

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         marketing, advertising, promotion, sale and distribution rights in the
         Territory for use in the Field made by GPI Holdings to APPI under the
         Marketing Rights Agreement; and

                  (vi)     Guilford granted to APPI a right of first offer
         covering all future drug-polymer cancer chemotherapeutic products that
         are developed directly by Guilford (and not pursuant to any
         collaboration with another party) specifically for the indication of
         brain cancer and for which Guilford controls the intellectual property
         rights covering the active chemotherapeutic agent incorporated into the
         polymer; and

         WHEREAS, GPI Holdings and GPI desire to reacquire the rights they
granted to APPI under the Marketing Rights Agreement and related agreements on
the terms and conditions contained herein and APPI desires to assign its rights
in the Product under the Marketing Rights Agreement back to GPI Holdings and GPI
on the terms and conditions set forth herein, whereby, among other things:

         (i)      Guilford shall issue three hundred thousand (300,000) shares
                  of GPI Common Stock to APPI pursuant to the terms and
                  conditions of the Stock Purchase Agreement attached hereto;

         (ii)     Pursuant to the terms and conditions of the Registration
                  Rights Agreement attached hereto, APPI shall obtain certain
                  rights to require GPI to register the GPI Common Stock issued
                  to APPI pursuant to the Stock Purchase Agreement;

         (iii)    The parties shall cooperate during the Transition Period (as
                  defined below) to effect the transfer of all Regulatory
                  Filings (as defined below), Regulatory Approvals (as defined
                  below) and data generated to support the foregoing, as well as
                  all Know-How (as defined below) and marketing and sales data
                  that relate to the Product (as defined below), from APPI to
                  Guilford;

         (iv)     The parties shall continue to perform pursuant to the
                  Marketing Rights Agreement and related agreements contemplated
                  thereby through the Transition Period, except to the extent
                  provided otherwise by this Agreement; and

         (v)      Upon the completion of the Transition Period, the Marketing
                  Rights Agreement, the related agreements contemplated thereby,
                  and the parties' rights and obligations thereunder shall
                  terminate, except to the extent otherwise provided by this
                  Agreement;

         WHEREAS, RPR Inc. and GPI are parties to that certain Stock Purchase
Agreement dated as of June 13, 1996, (the "1996 Stock Purchase Agreement"),
pursuant to which RPR Inc. acquired shares of GPI's common stock, and RPR Inc.
and GPI desire to modify the terms of the 1996 Stock Purchase Agreement on the
terms and conditions set forth herein;

         WHEREAS, RPR Inc. and GPI are parties to that certain Loan Agreement
dated as of June 13, 1996, (the "1996 Loan Agreement"), pursuant to which RPR
Inc. extended a line of

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credit to GPI, and RPR Inc. and GPI desire to terminate the 1996 Loan Agreement
on the terms and conditions set forth herein;

         NOW THEREFORE, in consideration of the mutual covenants and
consideration set forth herein, the parties hereto, intending to be legally
bound, hereby agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

         1.1      "Act" shall mean the Federal Food, Drug and Cosmetic Act, as
amended, and the regulations promulgated under such Act.

         1.2      "Affiliate" shall mean, when used with respect to a Person,
any other Person directly or indirectly controlling, controlled by, or under
common control with the subject Person. For purposes of this Agreement,
"control" means the direct or indirect ownership of over 50% of the outstanding
voting securities of a Person, or the right to receive over 50% of the profits
or earnings of a Person, or the right to control the policy decisions of a
Person.

         1.3      "Agreement" shall have the meaning set forth in the
introductory paragraph of this agreement.

         1.4      "ANDA" shall mean an "Abbreviated New Drug Application," as
defined in the Act, and all supplements thereto.

         1.5      "APPI" shall have the meaning set forth in the introductory
paragraph of this Agreement.

         1.6      "Aventis" shall mean APPI and RPR Inc. collectively.

         1.7      "Closing" shall have the meaning set forth in Section 2.1.

         1.8      "Closing Date" shall have the meaning set forth in Section
2.1.

         1.9      "FDA" shall mean the Food and Drug Administration of the
United States Department of Health and Human Services, or any successor agency
thereto.

         1.10     "Field" shall mean the treatment of tumors of the central
nervous system and the treatment of cerebral edema.

         1.11     "First Amendment to the Marketing Rights Agreement" shall mean
that certain Amendment No. 1 to Marketing, Sale and Distribution Rights
Agreement by and among APPI and Guilford, dated as of September 25, 1998.

         1.12     "First Surgery Trial" has the meaning set forth in the First
Amendment to the Marketing Rights Agreement.

         1.13     "GLIADEL Product" shall mean Guilford's GLIADEL(R) wafer,
PCPP:SA with 3.85% BCNU, and any and all Improvements thereto.

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         1.14     "GPI" shall have the meaning set forth in the introductory
paragraph of this Agreement.

         1.15     "GPI Holdings" shall have the meaning set forth in the
introductory paragraph of this Agreement.

         1.16     "Guilford" shall have the meaning set forth in the first
recital of this Agreement.

         1.17     "High Dose GLIADEL Product" shall mean any PCPP:SA product
with a BCNU dose higher than 3.85% which is (i) reasonably expected to have a
more advantageous efficacy profile than the GLIADEL Product and (ii) now or
hereafter owned or controlled by Guilford, and all Improvements to any such
product.

         1.18     "Improvement" to a product shall mean any and all inventions,
discoveries, developments, modifications and improvements, whether or not
patented or patentable, to such product.

         1.19     "IND" shall mean an "Investigational New Drug Application," as
defined in the Act.

         1.20     "Interim Agreement" shall mean that certain Interim Agreement,
dated as of October 5, 2000, by and among APPI and Guilford.

         1.21     "Know-How" shall mean all scientific and technical data,
instructions, processes, formulae, specifications, ingredient sources,
manufacturing procedures, methods and other information relating to the design,
composition, formulation, pre-clinical evaluation, clinical evaluation,
manufacture, use, sale, packaging, formulation or administration of the Product,
including, but not limited to, NDAs (and similar applications filed in
jurisdictions other than the U.S.), pharmacological, toxicological, analytical,
stability and clinical data, specifications and drug master files and/or health
registration dossiers and any other premarket application or registration owned
or controlled at any time during the term hereof by either party.

         1.22     "Licensed Trademark" shall mean GPI Holdings' GLIADEL
trademark and all goodwill associated with such trademark.

         1.23     "Marketing Rights Agreement" shall have the meaning set forth
in the first recital of this Agreement.

         1.24     "NDA" shall mean a "New Drug Application," as defined in the
Act, and all supplements thereto.

         1.25     "1996 Loan Agreement" shall have the meaning set forth in the
fourth recital of this Agreement.

         1.26     "1996 Stock Purchase Agreement" shall have the meaning set
forth in the third recital of this Agreement.

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         1.27     "1996 Manufacturing and Supply Agreement" shall mean that
certain Manufacturing and Supply Agreement, dated as of June 13, 1996 between
GPI and APPI, as amended by Amendment No. 1 dated June 7, 1999 and Amendment No.
2 dated June 26, 2000.

         1.28     "Other PCPP:SA/BCNU Products" shall mean all PCPP:SA-based
polymer products containing BCNU, other than the GLIADEL Product, that are now
or hereafter during the term of this Agreement owned or controlled by Guilford,
including, without limitation, High Dose GLIADEL Product, and all Improvements
to any of the foregoing.

         1.29     "Person" shall mean any corporation, partnership, joint
venture, other entity or natural person.

         1.30     "Product" shall mean the GLIADEL Product and all Other
PCPP:SA/BCNU Products.

         1.31     "Registration Rights Agreement" shall mean a Registration
Rights Agreement between GPI and APPI dated as of the Closing Date in the form
attached hereto and made a part hereof as Exhibit A.

         1.32     "Regulatory Approval" shall mean, with respect to any country,
(i) filing for and receipt of all governmental and regulatory registrations and
approvals (including, but not limited to, approvals of all final Product
labeling) required for the marketing and sale of the Product for the indication
for which it is being marketed in such country, and (ii) the receipt of
reimbursement approvals and a reimbursement price acceptable to Guilford from
the national health system or other appropriate governmental or regulatory
authorities in such country, except in those countries where such reimbursement
approvals and reimbursement price are not granted by a government or regulatory
authority (such as the United States).

         1.33     "Regulatory Filings" shall mean all applications, filings,
materials, studies, data and documents of any nature whatsoever filed with,
prepared in connection with or necessary to support any Regulatory Approval
process in any country or territory.

         1.34     "Stock Purchase Agreement" shall mean the Stock Purchase
Agreement dated as of even date herewith between GPI and APPI, the form of which
is attached hereto and made a part hereof as Exhibit B.

         1.35     "Territory" shall mean the entire world, excluding Denmark,
Finland, Norway, Sweden and Japan.

         1.36     "Transaction Agreements" shall mean, collectively, this
Agreement, the Registration Rights Agreement and the Stock Purchase Agreement.

         1.37     "Transition Date" shall mean December 31, 2000.

         1.38     "Transition Period" shall mean the period commencing on
Closing Date and ending on the Transition Date.

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                                    ARTICLE 2
                                     CLOSING

         2.1      Time and Place of the Closing. Subject to the terms and upon
satisfaction or waiver of the conditions set forth herein, including the
conditions to Closing set forth in this Article 2, the closing of the
transactions contemplated herein (the "Closing") shall occur on October 23,
2000, or such other date as the parties may agree (the "Closing Date"). The
Closing shall take place at the offices of Wilmer, Cutler & Pickering, 2445 M
Street, N.W., Washington, D.C. 20037-1420, at 4:00 p.m. on the Closing Date.

         2.2      Conditions to Guilford's Obligations to Close. The obligations
of Guilford to carry out the terms of this Agreement are subject to the
fulfillment on or before the Closing Date of each of the following conditions,
any of which may be waived by Guilford:

                  2.2.1    Representations and Warranties. The representations
and warranties of Aventis contained in Article 3 shall be true, correct and
complete in all material respects on and as of the Closing Date with the same
effect as if made on and as of such Closing Date.

                  2.2.2    Simultaneous Closing. Contemporaneously with the
Closing hereof, the "Closing" of the Stock Purchase Agreement (as such term is
defined therein) shall take place.

                  2.2.3    Closing Deliveries by APPI. Contemporaneously with
the Closing hereof APPI shall tender its execution and delivery of the
Registration Rights Agreement.

         2.3      Conditions to Aventis' Obligations to Close. The obligations
of Aventis to carry out the terms of this Agreement are subject to the
fulfillment on or before the Closing Date of each of the following conditions,
any of which may be waived by Aventis:

                  2.3.1    Representations and Warranties. The representations
and warranties of Guilford contained in Article 3 shall be true, correct and
complete in all material respects on and as of the Closing Date with the same
effect as if made on and as of such Closing Date.

                  2.3.2    Simultaneous Closing. Contemporaneously with the
Closing hereof, the "Closing" of the Stock Purchase Agreement (as such term is
defined therein) shall take place.

                  2.3.3    Closing Deliveries by Guilford.  Contemporaneously
with the Closing hereof, Guilford shall tender its execution and delivery of the
Registration Rights Agreement.

                                   ARTICLE 3
                         REPRESENTATIONS AND WARRANTIES

         3.1      Aventis Representations and Warranties. APPI and RPR Inc.
hereby represent and warrant to Guilford that:

                  3.1.1    Corporate Power. Each of APPI and RPR Inc. has the
corporate power and authority to execute, deliver and perform the Transaction
Agreements. The execution,

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delivery and performance of the Transaction Agreements by APPI and RPR Inc. have
been duly authorized by all necessary corporate action of APPI and RPR Inc.,
respectively;

                  3.1.2    Validity. Each of the Transaction Agreements, when
executed and delivered by Aventis, shall be the legal, valid and binding
obligation of Aventis, enforceable against Aventis in accordance with its terms,
except as such enforceability may be limited by bankruptcy law and other similar
laws affecting creditors' rights generally and by general principles of equity;

                  3.1.3    Non-Contravention. The execution, delivery and
performance of the Transaction Agreements by Aventis do not and will not (i)
conflict with, or constitute a breach or default under, or require the consent
of any third party under, Aventis' charter documents or any material license,
loan or other agreement, contract, commitment or instrument to which Aventis is
a party or any of its assets are bound, (ii) violate any provision of law,
statute, rule or regulation or any ruling, writ, injunction, order, judgment or
decree of any court, administrative agency or other governmental body, or (iii)
require the consent, approval or authorization of, or notice, declaration,
filing or registration with, any third party or any governmental or regulatory
authority;

                  3.1.4    No Litigation. There is no action or proceeding
pending or, in so far as Aventis knows, threatened against Aventis or any of its
Affiliates before any court, administrative agency or other tribunal which could
impact upon Aventis' right, power and authority to enter into any of the
Transaction Agreements or to carry out its obligations under any of the
Transaction Agreements;

                  3.1.5    Joint Inventions. There are no Joint Inventions (as
such term is defined in Section IV(H)(3) of the Marketing Rights Agreements);

                  3.1.6    Licensed Trademark.

                           (a)      The only trademark that has been used by the
parties pursuant to the provisions of Section III(A)(2) of the Marketing Rights
Agreement is GPI Holdings' GLIADEL trademark;

                           (b)      APPI has not granted a sublicense to any
third party to use the Licensed Trademark;

                  3.1.7    Distribution Rights. APPI has not granted marketing,
sales, sales agency and/or distribution rights to any third party with respect
to any rights conferred upon APPI under the Marketing Rights Agreement;

                  3.1.8    Subcontractors. Except as set forth on Schedule 3.1.8
or Schedule 5.6.4, APPI has not subcontracted any third parties to seek
Regulatory Approvals or to conduct clinical trials or studies with respect to
the Product;

                  3.1.9    Liability to Third Party Agents. Except as set forth
in Sections 5.4 and 5.6.4, Guilford shall have no liability or obligation to any
of the parties set forth on Schedule 3.1.8 as a result of the transactions
contemplated by this Agreement; and

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                  3.1.10   Ownership Rights. APPI owns the Know-How, Regulatory
Filings, Regulatory Approvals and marketing and sales data to be transferred to
Guilford pursuant to Article 6 free and clear of any encumbrances, license or
security interest or other similar right of third parties.

         3.2      Guilford Representations and Warranties.  GPI and GPI Holdings
each hereby represents and warrants to Aventis that:

                  3.2.1    Corporate Power. Each of GPI and GPI Holdings has the
corporate power and authority to execute, deliver and perform each of the
Transaction Agreements. The execution, delivery and performance of each of the
Transaction Agreements by GPI and GPI Holdings have been duly authorized by all
necessary corporate action of GPI and GPI Holdings, respectively;

                  3.2.2    Validity. Each of the Transaction Agreements, when
executed and delivered by Guilford, shall be the legal, valid and binding
obligation of Guilford, enforceable against Guilford in accordance with its
terms, except as such enforceability may be limited by bankruptcy law and other
similar laws affecting creditors' rights generally and by general principles of
equity;

                  3.2.3    Non-Contravention. The execution, delivery and
performance of the Transaction Agreements by Guilford do not and will not (i)
conflict with, or constitute a breach or default under, or require the consent
of any third party under, Guilford's charter documents or any material license,
loan or other agreement, contract, commitment or instrument to which Guilford is
a party or any of its assets are bound, (ii) violate any provision of law,
statute, rule or regulation or any ruling, writ, injunction, order, judgment or
decree of any court, administrative agency or other governmental body, or (iii)
require the consent, approval or authorization of, or notice, declaration,
filing or registration with, any third party or any governmental or regulatory
authority; and

                  3.2.4    No Litigation. There is no action or proceeding
pending or, in so far as Guilford knows, threatened against Guilford or any of
its Affiliates before any court, administrative agency or other tribunal which
could impact upon Guilford's right, power and authority to enter into any of the
Transaction Agreements or to carry out its obligations under any of the
Transaction Agreements.

                  3.2.5    Joint Inventions. There are no Joint Inventions (as
such term is defined in Section IV(H)(3) of the Marketing Rights Agreements).

                  3.2.6    Licensed Trademark. The only trademark that has been
used by the parties pursuant to the provisions of Section III(A)(2) of the
Marketing Rights Agreement is GPI Holdings' GLIADEL trademark.

         3.3      Knowledge. Where a representation or warranty contained in
this Article 3 is stated to be to a party's knowledge, this shall mean to the
actual knowledge of all of the officers and appropriate key personnel of such
party, after reasonable inquiry.

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         3.4      No Other Warranties. EXCEPT FOR THE EXPRESS WARRANTIES
CONTAINED IN THIS AGREEMENT, NEITHER GUILFORD NOR AVENTIS MAKE ANY WARRANTIES OR
REPRESENTATIONS, EXPRESS OR IMPLIED, IN FACT OR IN LAW, INCLUDING ANY IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
NON-INFRINGEMENT.

         3.5      Survival of Warranties. The provisions of this Article 3 shall
survive the expiration or sooner termination of the term of this Agreement.

                                   ARTICLE 4
       MODIFICATION OF CERTAIN EXISTING OBLIGATIONS AS OF THE CLOSING DATE

         4.1      Marketing Rights Agreement. Unless expressly provided
otherwise by this Agreement, between the Closing Date and the Transition Date
all rights and obligations of any party under the Marketing Rights Agreement
shall remain in full force and effect. Effective upon the Closing Date, the
parties agree that the Marketing Rights Agreement shall be modified as follows:

                  4.1.1    Exclusive Right. For purposes of clarification, it is
understood that Section III(A)(1) shall not be interpreted to restrict Guilford
from exercising its rights or performing its obligations under Articles 4, 5 and
9 of this Agreement.

                  4.1.2    Licensed Trademark. Guilford shall no longer be
prohibited pursuant to Section III(A)(2) from using the Licensed Trademark
itself or from granting other Persons rights to use the Licensed Trademark.

                  4.1.3    Assignment of Rights. Notwithstanding Section
III(A)(3) of the Marketing Rights Agreement, APPI shall no longer have the right
to grant any exclusive or non-exclusive marketing, sales, sales agency and/or
distribution rights, with respect to any rights conferred upon APPI under the
Marketing Rights Agreement, to any non-Affiliated third party.

                  4.1.4    Studies and Regulatory Approvals. Except as
contemplated by Section 5.6.4 of this Agreement, APPI shall no longer be
obligated pursuant to Sections III(B)(1), (2) or (3) to conduct clinical trials
or studies or take other steps and actions regarding Regulatory Approval in the
U.S. of the Product, nor will APPI take such actions except in coordination
with, and, following transfer of the NDA and IND as contemplated by Section
5.1.2 of this Agreement, with the prior approval not to be unreasonably withheld
or delayed of, Guilford. APPI shall no longer be obligated pursuant to Section
III(C)(2) to pursue Regulatory Approval of the Product other than in support of
Regulatory Filings made prior to the date of this Agreement in Italy, Canada and
Australia, which support shall be conducted by APPI in accordance with Section
5.5 of this Agreement.

                  4.1.5    Right of Review. Following transfer of the NDA and
IND as contemplated by Section 5.1.2, APPI shall have no further right pursuant
to Section III(B)(4) to review and comment on strategies and protocols of the
clinical trials and studies and regulatory submissions made by Guilford related
to the GLIADEL Product for the indication of the treatment of form(s) of
malignant glioma in the United States.

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                  4.1.6    Milestone Payments. APPI shall no longer be obligated
pursuant to Section III(D) to make any further payments to GPI or GPI Holdings
in consideration of obtaining Regulatory Approvals relating to the GLIADEL
Product.

                  4.1.7    Governance and Operations Committees. The provisions
of Sections III(G) and (H) of the Marketing Rights Agreement with respect to the
establishment and meeting of the Governance Committee and Operations Committee
shall be of no further force and effect.

                  4.1.8    Joint Development Activities. APPI shall no longer be
obligated to sponsor and fund any development activities pursuant to Section
III(I).

                  4.1.9    Right of First Offer. The right of first offer
granted to APPI pursuant to Section III(J) shall be revoked and APPI shall have
no rights with respect to the any Qualifying Product Candidate (as such term is
defined in the First Amendment to the Marketing Rights Agreement).

                  4.1.10   Confidentiality. The second sentence of Section
IV(A)(1) shall be amended and restated to read as follows:

                  "The Receiving Party shall, during the term of this Agreement,
                  and for seven (7) years after the expiration or sooner
                  termination of the term of this Agreement, make no use of such
                  confidential information except (x) to advance the purposes of
                  this Agreement in accordance with its provisions or (y) to
                  advance the purposes of that certain Rights Reversion
                  Agreement between the parties dated as of October 23, 2000 in
                  accordance with its provisions, which purposes shall include
                  the transition of the development, commercialization and sale
                  of the Product to Guilford from APPI and Guilford's
                  corresponding disclosure of such confidential information to
                  potential distributors, vendors of regulatory services and
                  other third party agents of Guilford. Each party shall use the
                  same efforts to keep secret and prevent the disclosure of such
                  confidential information to third parties as it would use with
                  respect to its own confidential information."

                  4.1.11   Termination.

                           (a)      APPI shall no longer have the right pursuant
to Section IV(D)(2) to terminate the Marketing Rights Agreement in the event of
a Change of Control (as such term is defined in the Marketing Rights Agreement).

                           (b)      APPI shall no longer have the right pursuant
to Section IV(D)(5) or Section IV(F)(4) to sell out its stock of any Product it
possesses or has committed to purchase in the event of a termination of the
Marketing Rights Agreement, and the disposition of such Product upon termination
of the Marketing Rights Agreement shall instead be governed by Section 5.6.2 of
this Agreement.

                  4.1.12   Events of Default. A breach by either party of any
material provision of the 1996 Loan Agreement, or defaults in the performance or
observance of any material provision of such agreement, shall no longer
constitute an "Event of Default" under the Marketing Rights Agreement pursuant
to Section IV(E).

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                  4.1.13   Inventions. APPI shall no longer have the right
pursuant to Section IV(H)(1) to require Guilford (a) to file, prosecute or
maintain patents or patent applications on any GPI Inventions (as such term is
defined in the Marketing Rights Agreement) or (b) to cooperate with APPI to
prepare, review or execute any such patent applications or other papers as may
be necessary to enable the protection of the GPI Inventions (as such term is
defined in the Marketing Rights Agreement) by patent and, notwithstanding the
survival provisions in Section IV(H)(9) and Section IV(D)(4), such rights shall
terminate and be of no further force and effect as of the Closing Date.

                  4.1.14   Infringement.

                           (a)      If, as a result of the manufacture, use or
sale of the Product, Guilford is sued for patent infringement or threatened with
such a lawsuit or other action by a third party, Guilford shall no longer have
the obligation, pursuant to Section IV(I)(1), (x) to meet with APPI to analyze
the infringement claim and the avoidance of the same, or (y) to obtain the prior
written consent of APPI prior to the settlement of any such claim, suit,
threatened suit or action and, notwithstanding the survival provisions in
Section IV(I)(3) and Section IV(D)(4), such obligations shall terminate and be
of no further force and effect as of the Closing Date.

                           (b)      If, as a result of the manufacture, use or
sale of the Product, Guilford or APPI or any of its Affiliates is sued for
patent infringement or threatened with such a lawsuit or other action by a third
party, and as a result it is necessary to obtain a license from such third
party, Guilford shall no longer have the obligation, pursuant to Section
IV(I)(1), to involve APPI in efforts to obtain and negotiate a license from such
third party and, notwithstanding the survival provisions in Section IV(I)(3) and
Section IV(D)(4), such obligations shall terminate and be of no further force
and effect as of the Closing Date.

                           (c)      Notwithstanding the survival provisions in
Section IV(I)(3) and Section IV(D)(4), the provisions of Section (IV)(I)(2)
relating to infringement of a patent involving the Product by a third party
shall terminate and be of no further force and effect as of the Closing Date.

                  4.1.15   Certain Covenants of Guilford.

                           (a)      The obligations of Guilford and its
Affiliates pursuant to Section IV(J)(iv), which prohibit Guilford and its
Affiliates from appointing any distributor other than APPI in the Territory
during the term of the Marketing Rights Agreement, shall be deemed modified to
the extent necessary to permit Guilford and its Affiliates to solicit,
interview, appoint and contract with distributors and prepare them to begin
distribution of the Product in the Territory; provided, however, that any such
distributors shall not actually begin distribution of the Product in the
Territory until the Transition Date.

                           (b)      The obligations of Guilford and its
Affiliates pursuant to Section IV(J)(v), which require Guilford and its
Affiliates to refer to APPI any leads concerning prospective customers in the
Territory which come to the attention of GPI during the term of the Marketing
Rights Agreement, shall terminate and be of no further force and effect as of
the Closing Date.

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         4.2      Manufacturing and Supply Agreement. Unless expressly provided
otherwise by this Agreement, during the Transition Period all rights and
obligations of any party under the 1996 Manufacturing and Supply Agreement shall
remain in full force and effect. Effective upon the Closing Date, the parties
agree that the 1996 Manufacturing and Supply Agreement shall be modified as
follows:

                  4.2.1    Definition of Territory. The definition of
"Territory" shall be amended and restated to read as follows:

                  "Territory" shall mean the entire world, excluding Denmark,
                  Finland, Norway, Sweden and Japan.

                  4.2.2    Forecasts. APPI shall no longer be obligated to
provide forecasts or orders for Product pursuant to Sections II(B)(1) and
II(B)(2).

                  4.2.3    Ownership of Trademarks. Notwithstanding any
provision in Section II(D)(3) to the contrary, Guilford shall be the exclusive
owner of and have all rights to (i) the Licensed Trademark, together with the
goodwill symbolized by such trademark, and (ii) copyrights, plans, ideas, names,
slogans, artwork and all other intellectual property, if any, in each case
exclusive to the GLIADEL Product; provided, however, for clarification the
foregoing shall exclude any corporate or division name of Rhone-Poulenc Rorer
Pharmaceuticals Inc., Aventis or their respective Affiliates, any logos of
Rhone-Poulenc Rorer Pharmaceuticals Inc., Aventis or their respective
Affiliates, any trademark of Rhone-Poulenc Rorer Pharmaceuticals Inc., Aventis
or their respective Affiliates and all NDC numbers of Aventis or its Affiliates.

                  4.2.4    Termination. APPI shall no longer have the right
pursuant to Section III(D)(3) to terminate the 1996 Manufacturing and Supply
Agreement in the event of a Change of Control (as such term is defined in the
1996 Manufacturing and Supply Agreement).

                  4.2.5    Events of Default. A breach by either party of any
material provision of the 1996 Loan Agreement, or defaults in the performance or
observance of any material provision of such agreement, shall no longer
constitute an "Event of Default" under the 1996 Manufacturing and Supply
pursuant to Section III(E).

                  4.2.6    Remedies. APPI shall no longer have the right
pursuant to Section III(F)(4) to sell out its stock of any Product it possesses
or has committed to purchase in the event of a termination of the 1996
Manufacturing and Supply Agreement, and the disposition of such Product upon
termination of the 1996 Manufacturing and Supply shall instead be governed by
Section 5.6.2 of this Agreement.

                  4.2.7    Certain Covenants of GPI. The obligations of Guilford
and its Affiliates pursuant to Section III(I)(iv), which require Guilford and
its Affiliates to refer to APPI any leads concerning prospective customers in
the Territory which come to the attention of GPI during the term of the 1996
Manufacturing and Supply Agreement, shall terminate and be of no further force
and effect as of the Closing Date.

         4.3      1996 Stock Purchase Agreement. Unless expressly provided
otherwise by this Agreement, all rights and obligations of any party under the
1996 Stock Purchase Agreement

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<PAGE>   13

shall remain in full force and effect. Effective upon the Closing Date, the
parties agree that the 1996 Stock Purchase Agreement shall be modified as
follows:

                  4.3.1    Additional Shares. RPR Inc. shall no longer have any
right or obligation to purchase, and GPI shall no longer have any right or
obligation to sell, the Additional Shares (as defined in the 1996 Stock Purchase
Agreement) and as a result, there shall be no Second Closing Date (as defined in
the 1996 Stock Purchase Agreement).

                  4.3.2    Covenants to Perform. The respective covenants of
APPI and GPI to perform the agreements to be performed by them under the
Transaction Documents (as defined in the 1996 Stock Purchase Agreement) shall be
modified to include only those agreements to be performed by them under the
Transaction Documents as amended hereby or as may be amended by the parties in
the future.

                  4.3.3    Standstill. The standstill provisions set forth in
Section 7.01 of the 1996 Stock Purchase Agreement shall no longer be of any
force or effect, and such matters shall be governed by Section 7.01 of the Stock
Purchase Agreement.

                  4.3.4    Lock Up. The lock up provisions set forth in Section
7.02 of the 1996 Stock Purchase Agreement shall no longer be of any force or
effect.

         4.4      1996 Loan Agreement. Effective upon the Closing Date, the
parties agree that the 1996 Loan Agreement shall be terminated and be of no
further force and effect and as a result RPR Inc. shall have no further
obligation to advance any funds to GPI pursuant to the 1996 Loan Agreement.

         4.5      Interim Agreement. Effective upon the Closing Date, the
parties agree that the Interim Agreement shall no longer be of any force or
effect, and the matters contained therein shall be governed by this Agreement.

                                   ARTICLE 5
                      OBLIGATIONS DURING TRANSITION PERIOD

         Unless expressly provided otherwise by this Agreement, during the
Transition Period all rights and obligations of any party under the Marketing
Rights Agreement shall remain in full force and effect. In addition, during the
Transition Period:

         5.1      Cooperation.

                  5.1.1    General Access. APPI shall grant Guilford full access
to documents, meetings and any other communications (both internal and with any
third parties) regarding clinical trials, registration efforts, and marketing,
sales and distribution activities, each with respect to the Product. APPI shall
work jointly with Guilford with respect to the foregoing activities and will
cooperate with and reasonably assist Guilford in Guilford's efforts to build its
commercial operations with respect to the Product. Such assistance will include,
for example, promptly supplying Guilford with copies of marketing and sales
records, reports, plans and other

RIGHTS REVERSION AGREEMENT             13
<PAGE>   14

information that is related to the Product and that is in APPI's possession or
control. APPI shall deliver such information in electronic or hard copy
versions, as Guilford may reasonably request.

                  5.1.2    Transfer of NDA and IND. Immediately following the
Closing, the parties shall file with the FDA the information required pursuant
to 21 C.F.R. Section 314.72 for the transfer of the NDA and IND for the GLIADEL
Product from APPI to Guilford. APPI shall file the information required of a
former owner as set forth in Exhibit C hereto, and Guilford shall file the
information required of a new owner as set forth in Exhibit D hereto. APPI may
retain an archival copy of such NDA and IND, including information required to
be kept under applicable regulations.

                  5.1.3    Transition of NDA Activities. The parties will agree
upon procedures to ensure a smooth transition from APPI to Guilford on or before
the Transition Date of the activities required to be undertaken by the holder of
the NDA (and corresponding foreign Regulatory Filings) for the GLIADEL Product,
including, without limitation, adverse experience reporting, quarterly and
annual FDA reports, complaint and sample tracking, product recalls and
communication with health care professionals and customers.

         5.2      Communications with Regulatory Authorities.

                  5.2.1    FDA. Upon transfer of the NDA for the GLIADEL Product
to Guilford, Guilford shall assume all responsibility for communication with the
FDA that relates to the Product, except as contemplated by Section 5.6.5 hereof.
Guilford shall not purport to represent APPI in any such communication with the
FDA or attribute any statements to APPI or any of its Affiliates in any such
communication.

                  5.2.2    Foreign Regulatory Authorities. During the Transition
Period, APPI shall give Guilford reasonable prior written notice and the right
to attend any meeting between APPI and any foreign regulatory authority relating
to the Product and provide Guilford with a true and complete copy of each
communication that will be made during the Transition Period between APPI and
any foreign regulatory authority that relates to the Product, and the right to
review and participate in any response to any such communication. APPI shall be
responsible for making presentations to any foreign regulatory authority that
relate to the Product during any joint meetings and for responding to questions
and comments from such foreign regulatory authority with respect to its
Regulatory Filing, but shall solicit and reasonably consider the input of
Guilford prior to making such a presentation or response; provided, however,
that APPI shall not be required to take any action that APPI determines in good
faith would jeopardize its standing and reputation with any foreign regulatory
authority or violate any applicable provision of law, statute, rule or
regulation. APPI and Guilford shall promptly provide the other with notes from
any in-person or teleconference meeting with any foreign regulatory authority
related to the Product at which the other is not present. Notwithstanding the
foregoing, upon a transfer in accordance with Article 6 of a foreign Regulatory
Approval or Regulatory Filing prior to the Transition Date, (i) Guilford shall
assume all responsibility for presentations to and communications with the
relevant regulatory authority that relates to the Product and (ii) APPI shall be
relieved of any responsibility therefor, except as contemplated by Section 5.6.5
hereof. Guilford shall not purport to represent APPI in any meeting with any
foreign regulatory authority or attribute any statements to APPI or any of its
Affiliates in any such communication.

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<PAGE>   15

         5.3      Joint Transition Team. Upon the Closing Date, the parties
shall establish a Joint Transition Team which shall remain in place during the
Transition Period and which shall be responsible for the smooth and effective
implementation of the transition activities contemplated by this Agreement and
for developing and executing a plan to effect the transfers to take place
pursuant to Article 6. The members of the Joint Transition Team shall be as set
forth on Schedule 5.3. Any replacements or proxies for the foregoing persons
shall be equivalently senior personnel. The parties shall cause their respective
members of the Joint Transition Team to make themselves available as reasonably
necessary to carry out such implementation. Any impasse among the members of the
Joint Transition Team that is not resolved within seven (7) business days shall
be referred to dispute resolution pursuant to Section 12.14.2.

         5.4      First Surgery Trial. Guilford will have the right to direct,
and will be responsible for directing, the completion of the First Surgery Trial
data analysis and final study report, and APPI will instruct PPD Development to
follow Guilford's reasonable direction with respect thereto. APPI will not (i)
make any public statements, written or verbal or (ii) engage in any
communications with the FDA or any corresponding foreign regulatory authority,
in either case relating to the First Surgery Trial and its results, except (A)
pursuant to a request for information from such regulatory authority, (B) as
required under applicable law, statute, rule or regulation, or (C) as determined
in good faith by APPI to be necessary in order to not jeopardize APPI's standing
and reputation with any such regulatory authority; provided, however, that (1)
unless, with respect to clauses (A) and (B), it is not reasonably practicable,
APPI shall coordinate with Guilford with respect to any such communications,
including, providing to Guilford a reasonable prior opportunity to review and
comment on any such communications and considering in good faith the comments of
Guilford prior to dissemination of any such communications, and (2) in each
case, APPI shall provide Guilford with a copy of the final version of any such
communication made in writing or a written summary of any such communication
made verbally after dissemination of any such communication. The provisions
contained in the preceding sentence shall survive the termination or expiration
of this Agreement. APPI shall be liable for all bills of PPD Development and any
other creditors relating to the First Surgery Trial accrued for the completion
of the data analysis and final study report; provided, however, that Guilford
shall be responsible for any charges incurred by APPI relating to additional
work to or changes from the current plan for completion of the First Surgery
Trial that may be requested by Guilford of PPD Development or such other
creditors. Notwithstanding any provision in the Marketing Rights Agreement to
the contrary, Guilford shall have the right to direct the communication of the
data, analyses and results of the First Surgery Trial to its consultants and the
FDA and, in coordination with APPI, to investigators. Guilford will be
responsible for leading the Trial Executive Committee and will decide upon the
modalities of dissemination of the First Surgery Trial results (e.g.,
investigators, IDMC, Congresses, press releases and publications). Guilford will
provide to APPI a reasonable prior opportunity to review and comment on the
substance of any and all such communications, and Guilford shall consider in
good faith comments of APPI prior to such dissemination; provided, however, that
Guilford shall not have to provide APPI such opportunity to review and comment
on communications the substance of which has previously been provided to APPI
pursuant to the foregoing. Guilford shall not purport to represent APPI or
attribute any statements to APPI or any of its Affiliates in any of the
foregoing communications or other actions. If Guilford breaches its obligations
pursuant to the preceding sentence or if any third party refers to APPI or any
of its Affiliates in a public statement relating to the First Surgery Trial,
then APPI shall be entitled to make a clarifying disclosure; provided,

RIGHTS REVERSION AGREEMENT             15
<PAGE>   16

however, that any such clarifying disclosure made by APPI relating to the First
Surgery Trial and its results shall be subject to APPI's obligations in the
second sentence of this Section 5.4 to coordinate such communications with
Guilford.

         5.5      Registration Efforts. During the Transition Period, as
contemplated by Section 4.1.4 hereof, APPI shall continue to seek Regulatory
Approvals in accordance with the terms of the Marketing Rights Agreement for
recurrent indication in Italy, Canada and Australia, except to the extent that
Guilford assumes such responsibility in which event Guilford shall be
responsible for the conduct and cost of any such activities. In the event
Guilford assumes such responsibility, APPI shall assist Guilford in seeking such
Regulatory Approval by supplying Guilford with copies of relevant documents and
communications, informing Guilford of the status of the applicable Regulatory
Filings. Notwithstanding any provision in the Marketing Rights Agreement to the
contrary, the parties agree that during the Transition Period, or until such
earlier time as Guilford may assume responsibility for such activities, APPI's
activities with respect to seeking the foregoing Regulatory Approvals shall be
subject to reasonable coordination with Guilford; provided, however, that (i)
APPI shall not be required to take any action that APPI determines in good faith
would jeopardize its standing and reputation with any foreign regulatory
authority or violate any applicable provision of law, statute, rule or
regulation, and (ii) no request of Guilford shall increase any obligation or
cost to APPI beyond that required by the applicable terms of the Marketing
Rights Agreement. APPI shall have no other obligation (or right) to seek
Regulatory Approvals in accordance with the terms of the Marketing Rights
Agreement, including no obligation (or right) to prepare and file with the FDA
(and corresponding foreign regulatory authorities) the Supplemental NDA (and
corresponding foreign Regulatory Filings) with respect to the results of the
First Surgery Trial, and APPI may terminate internal efforts and arrangements
with third parties related to such activities. Any such Regulatory Filings, if
made, shall be the sole responsibility of Guilford, and all costs and expenses
related to preparation and filing of any such Regulatory Filings, including
without limitation the costs and expenses of third parties (such as Quintiles,
Inc.), which are incurred by Guilford shall be paid for by Guilford.

         5.6      Ongoing APPI Commercial Operations. APPI shall continue the
commercialization and sale of the Product in accordance with the terms of the
Marketing Rights Agreement and shall carry out its corresponding activities and
obligations, as follows:

                  5.6.1    No Purchase of Inventory. Notwithstanding its
obligation pursuant to Section III(A)(3) of the Marketing Rights Agreement to
maximize sales of the Product, and notwithstanding any purchase forecasts or
orders it has provided pursuant to the 1996 Manufacturing and Supply Agreement,
APPI shall not be required to purchase from Guilford any further Product.

                  5.6.2    Disposition of Unsold Inventory. Subject to Section
5.6.1, APPI shall use commercially reasonable efforts to market, sell and
distribute the Product and to maximize sales of the Product in accordance with
the terms of Section III(A)(3) of Marketing Rights Agreement; provided, however,
that to the extent that, in spite of such efforts, APPI is unable to sell all of
its inventory of Product during the Transition Period, promptly after the
Transition Date it shall destroy (and certify as so destroyed) any remaining
inventory, other than such inventory located at Dagenham or Frankfurt with a
remaining shelf life of at least six months at the Transition Date

RIGHTS REVERSION AGREEMENT             16
<PAGE>   17

which Guilford shall purchase on the Transition Date for $1000 per dose, with
shipment to a site within the European Union designated by Guilford at
Guilford's expense.

                  5.6.3    Packaging and Labeling. The parties acknowledge that
certain inventory of Product in the possession of Guilford existing as of the
date hereof may contain packaging and labeling with the names, logos, trademarks
and NDC numbers of APPI or any of its Affiliates. Guilford may distribute such
existing inventory until the end of the six-month period following the
Transition Date; provided, however, that Guilford (i) shall not distribute any
such Product that is within three months of its expiration date and (ii) shall
not, and shall have no right to, use such names, logos, trademarks or NDC
numbers for any other purpose and shall acquire no right, title or interest
therein.

                  5.6.4    Marketing and Sales Activities. Guilford shall direct
the planning and conduct or, if it shall so determine, the cancellation, of: (i)
the GLIADEL presentation at the Society for Neurooncology scheduled to start on
November 8, 2000 in Chicago, Illinois; and (ii) the November conference in
Puerto Rico to educate neurosurgeons about the results of the First Surgery
Trial. APPI shall use reasonable efforts to assist Guilford in the conduct of
such meetings. APPI will continue to support, or Guilford at its discretion may
assume, the existing Unrestricted Education Grants, media plan, public relations
plan and the GO Project Grant through the Transition Date (except to the extent
that Guilford may request APPI to cease any such activities). Guilford will
reimburse APPI promptly upon receipt of an invoice from APPI for its
out-of-pocket expenses incurred for each of the foregoing meetings, grants and
plans, including without limitation any such expenses related to canceled
meetings, grants or plans. For informational purposes, APPI's budget estimates
for the foregoing activities are as follows: Puerto Rico, $760,000; Unrestricted
Education Grants, $110,000; media plan, $33,575; public relations plan, $10,000;
and GO Project Grant, $132,375. Furthermore, Guilford shall assume the conduct
of the grant-in-aid studies set forth in Schedule 5.6.4 designated as committed
at its sole expense (but only to the extent of the total committed amount for
such studies as set forth in Schedule 5.6.4; provided, that, Guilford shall be
responsible for any additional costs resulting from changes to such studies
requested or directed by Guilford) and APPI shall be relieved of the obligation
to conduct any activities so assumed by Guilford and shall terminate any
grant-in-aid studies not set forth in Schedule 5.6.4; provided, however, that
with respect to any grant-in-aid studies not set forth in Schedule 5.6.4, APPI
shall refer to Guilford any inquiries from parties conducting those studies
concerning resumption of their work.

                  5.6.5    Regulatory Activities. During the Transition Period,
APPI shall, in consultation with and as reasonably requested by Guilford,
discharge all regulatory obligations relating to the Product, including
assisting Guilford in preparing NDA annual reports and other required
supplemental filings with the FDA and preparing such reports and filings with
corresponding foreign regulatory authorities, performing activities related to
European Union importation, and collecting and reporting adverse events.

         5.7      APPI Employees. APPI shall provide sufficient human and
corporate resources to fulfill its obligations under the Marketing Rights
Agreement and under this Agreement.

RIGHTS REVERSION AGREEMENT             17
<PAGE>   18

         5.8      Ordinary Course of Business. During the Transition Period,
APPI shall continue to act in the ordinary course of business, consistent with
its past practices, with respect to the sale of the Product, including, but not
limited to, the terms and conditions of sale of the Product.

                                   ARTICLE 6
                   TRANSFERS ON OR BEFORE THE TRANSITION DATE

         On or before the Transition Date, or with respect to any item below on
such earlier date as is reasonably practicable following notice by Guilford to
APPI, APPI shall transfer to Guilford the following:

         6.1      Know How and Clinical Data. All Know-How, including all
clinical and other data, analyses and reports (a) used, obtained or generated to
support APPI's pursuit of Regulatory Approvals (whether or not actually used) or
(b) that otherwise relates to the Product, provided to Guilford in the most
appropriate format available to support regulatory filings; provided, however,
that to the extent APPI requires access to such data to comply with applicable
legal requirements pertaining to APPI's performance under the Marketing Rights
Agreement or this Agreement, subject to Article 9, Guilford shall allow APPI a
right of access (including the right to take copies of records) and right of
reference to all such data;

         6.2      Other Regulatory Filings and Approvals. All Regulatory Filings
(for purposes of this Section 6.2, including both filed and draft versions)
(other than the NDA and IND filed with the FDA to be transferred in accordance
with Section 5.1.2 hereof) and Regulatory Approvals; provided, however, that if
legal requirements beyond APPI's control prevent APPI from transferring any
Regulatory Filing or Regulatory Approval to GPI Holdings, APPI shall allow
Guilford a right of reference to any such Regulatory Filing or Regulatory
Approval; provided, further, that Guilford shall take such action prior to the
Transition Date as is necessary to enable such transfer of all Regulatory
Filings and Regulatory Approvals and APPI shall close all Regulatory Filings and
Regulatory Approvals as of the Transition Date; provided, however, that if,
despite Guilford taking such action, the relevant regulatory authority has not
effectuated transfer of the relevant Regulatory Filing or Regulatory Approval as
of the Transition Date, then upon the written request of Guilford (including
reasonable evidence of Guilford having taken the necessary actions to enable
such transfer) APPI shall continue to support such Regulatory Filing or
Regulatory Approval in accordance with the terms of this Agreement for a
reasonable period of time after the Transition Date, not to exceed 45 days,
subject to prompt reimbursement by Guilford to APPI for any and all reasonable
costs or expenses (whether internal or out-of-pocket) related to such
continuation of support and to the continuation during such period of time of
the provisions of this Agreement related to Guilford's obligations to coordinate
with, and where applicable seek approval from, APPI with respect to
communications with the relevant regulatory authority and other disclosures and
provided that APPI shall have no further obligations with respect to the Product
in such country or countries, including sales, marketing or distribution; and

         6.3      Marketing and Sales Information. All marketing and sales data
in the possession or control of APPI that relate to the Product, including,
without limitation, customer lists,

RIGHTS REVERSION AGREEMENT             18
<PAGE>   19

marketing, distribution and sales plans, methods and systems, sales figures and
sales projections and training materials.

                                   ARTICLE 7
                     OBLIGATIONS AFTER THE TRANSITION PERIOD

         Effective as of the Transition Date, the Marketing Rights Agreement
shall terminate and, except for those rights and obligations of any party under
the Marketing Rights Agreement that expressly survive the termination of such
agreement pursuant to either the terms of the Marketing Rights Agreement (as
modified by this Agreement) or the terms of this Agreement, all rights and
obligations of any party under the Marketing Rights Agreement, including all
licenses granted to APPI by GPI or GPI Holdings thereunder, shall cease to be of
further effect. After the Transition Period, APPI shall, for a period of six
months:

         7.1      Regulatory Approval Information.  Provide to Guilford such
information in APPI's possession as may be reasonably requested by Guilford to
obtain Regulatory Approvals throughout the Territory for use in the Field.

         7.2      Adverse Event Reporting.  Continue to inform GPI of all
material written customer complaints, adverse reaction information or
notifications, correspondence, etc. with respect to the use of the Product that
may come to its attention;

         7.3      Infringement of Third Parties. Notify GPI should it become
aware of the Product infringing any patents, patent rights, patent applications,
inventions, trademarks, service marks or tradenames, copyrights, confidential
information, trade secrets or any other proprietary rights or processes of any
other Person; and

         7.4      Infringement by Third Parties.  Notify GPI should it become
aware that there is infringement of a patent involving the Product by any third
party.

                                   ARTICLE 8
     MODIFICATION OF CERTAIN OBLIGATIONS EFFECTIVE UPON THE TRANSITION DATE

         8.1      Marketing Rights Agreement. Effective as of the Transition
Date, the Marketing Rights Agreement shall terminate and, except for those
rights and obligations of any party under the Marketing Rights Agreement that
expressly survive the termination of such agreement pursuant to either the terms
of such agreement (as modified by this Agreement) or the terms of this
Agreement, all rights and obligations of any party under the Marketing Rights
Agreement shall cease to be of further effect. As to those rights and
obligations of any party under the Marketing Rights Agreement that do expressly
survive the termination thereof, the parties agree that effective as of the
Transition Date they shall be modified as follows:

                  8.1.1    Product Liability.  The first and second sentences of
Section IV(C)(2) shall be amended and restated to read as follows:

                  "The parties desire to separately allocate between themselves
                  the risks and costs of any product liability claims from third
                  parties with respect to the Product

RIGHTS REVERSION AGREEMENT             19
<PAGE>   20

                  (whether related to the safety or efficacy of the Product or
                  arising out of alleged defects in material, design or
                  workmanship of the Product or the use, marketing, advertising,
                  promotion, or distribution of the Product, but excluding those
                  claims (1) for which GPI and GPI Holdings are obligated to
                  defend, indemnify and hold the RPR Indemnitees harmless under
                  Section IV(C)(1)(a), and (2) for which RPR is obligated to
                  defend, indemnify and hold the GPI Indemnitees harmless under
                  Section IV(C)(1)(b)) (hereafter, a "Product Liability Claim").
                  Any losses, obligations, liabilities, penalties and damages
                  (including but not limited to compensatory and punitive
                  damages), costs and expenses (including reasonable attorneys'
                  fees), arising out of a Product Liability Claim (x) if related
                  to Product that is sold prior to the Transition Date (as
                  defined in the Rights Reversion Agreement between Aventis and
                  Guilford dated as of October 23, 2000), shall be shared
                  equally by APPI and Guilford and (y) if related to Product
                  that is sold on or after the Transition Date, shall be borne
                  by Guilford."

                  8.1.2    Confidentiality and Press Releases.

                           (a)      The third sentence of Section IV(A)(1) shall
be amended and replaced to read as follows:

                           "Information disclosed by the Disclosing Party shall
                           remain the sole and absolute property of the
                           Disclosing Party, subject to (x) the rights granted
                           in this Agreement and the transactions contemplated
                           herein and (y) the rights granted in that certain
                           Rights Reversion Agreement between Aventis and
                           Guilford dated as of October 23, 2000 and the
                           transactions contemplated therein, including the
                           transfer of certain information by APPI to Guilford
                           thereunder and the corresponding change in the nature
                           of such information from the proprietary and
                           confidential information of APPI to the proprietary
                           and confidential information of Guilford. Nothing in
                           this Agreement shall limit the use or disclosure by a
                           party of its own proprietary or confidential
                           information, including the information to be
                           transferred by APPI to Guilford under the Rights
                           Reversion Agreement which upon such transfer shall
                           become the confidential and proprietary information
                           of Guilford."

                           (b)      Notwithstanding the survival provisions in
Section IV(A)(5) and Section IV(D)(4), Section IV(A)(2) providing APPI with the
right to disclose information to its wholesalers and other direct customers as
necessary to effectively market and distribute the Product shall terminate and
be of no further force and effect as of the Transition Date.

                           (c)      Notwithstanding the survival provisions in
Section IV(A)(5) and Section IV(D)(4), Section IV(A)(3) relating to the
coordination of press releases and other public announcements by the parties
shall terminate and be of no further force and effect as of the Transition Date.

                  8.1.3    Joint Inventions.  Notwithstanding the survival
provisions in Section IV(H)(9) and Section IV(D)(4) of the Marketing Rights
Agreement, Sections IV(H)(3) through

RIGHTS REVERSION AGREEMENT             20
<PAGE>   21

IV(H)(8), regarding Joint Inventions, shall terminate and be of no further force
and effect as of the Transition Date.

         8.2      1996 Manufacturing and Supply Agreement. Effective as of the
Transition Date, the 1996 Manufacturing and Supply Agreement shall terminate
and, except for those rights and obligations of any party under the 1996
Manufacturing and Supply Agreement that expressly survive the termination of
such agreement pursuant to either the terms of such agreement (as modified by
this Agreement) or the terms of this Agreement, all rights and obligations of
any party under the 1996 Manufacturing and Supply Agreement shall cease to be of
further effect. As to those rights and obligations of any party under the 1996
Manufacturing and Supply Agreement that do expressly survive the termination
thereof, the parties agree that they shall be modified as follows:

                  8.2.1    Recalls.  The third to last sentence of Section II(G)
shall be amended and restated to read as follows:

                  "If neither party is responsible for such breach and the
                  Product subject to corrective or market action was sold prior
                  to the Transition Date (as defined in the Rights Reversion
                  Agreement between Aventis and Guilford dated as of October 23,
                  2000), then both parties will share equally the costs. If
                  neither party is responsible for such breach and the Product
                  subject to corrective or market action was sold after to the
                  Transition Date, then Guilford shall bear the costs."

                  8.2.2    Product Liability.  The first and second sentences of
Section III(C)(2) shall be amended and restated to read as follows:

                  "The parties desire to separately allocate between themselves
                  the risks and costs of any product liability claims from third
                  parties with respect to the Product (whether related to the
                  safety or efficacy of the Product or arising out of the
                  alleged defects in material, design or workmanship of the
                  Product or the use, marketing, advertising, promotion, or
                  distribution of the Product, but excluding those claims (1)
                  for which GPI and GPI Holdings are obligated to defend,
                  indemnify and hold the RPR Indemnitees harmless under Article
                  III.C.1.a., and (2) for which RPR is obligated to defend,
                  indemnify and hold the GPI Indemnitees harmless under Article
                  III.C.1.b) (hereafter, a "Product Liability Claim"). Any
                  losses, obligations, liabilities, penalties and damages
                  (including but not limited to compensatory and punitive
                  damages), costs and expenses (including reasonable attorneys'
                  fees), arising out of a Product Liability Claim (x) if related
                  to Product that is sold prior to the Transition Date (as
                  defined in the Rights Reversion Agreement between APPI and
                  Guilford dated as of October 23, 2000), shall be shared
                  equally by APPI and Guilford and (y) if related to Product
                  that is sold on or after the Transition Date, shall be borne
                  by Guilford."

         8.3      Returns. Effective as of the Transition Date, Guilford shall
be responsible for all obligations with respect to returned units of Product;
provided, that, until the end of the three-month period following the Transition
Date, APPI shall reimburse Guilford at the rate of $1,000

RIGHTS REVERSION AGREEMENT             21
<PAGE>   22

per box of Product for returned units of Product bearing lot numbers of Product
sold to APPI under the 1996 Manufacturing and Supply Agreement for up to 36
boxes of Product.

         8.4      Regulatory Responsibilities. Effective as of the Transition
Date, Guilford shall assume all regulatory responsibilities for the Product,
including, without limitation, adverse experience reporting, quarterly and
annual FDA reports, complaint and sample tracking, product recalls and
communication with health care professionals and customers, and assume all fee
obligations for holders of NDAs (and corresponding foreign Regulatory Filings)
for the GLIADEL Product.

                                   ARTICLE 9
                         CONFIDENTIALITY; PRESS RELEASES

         9.1      Confidentiality.

                  9.1.1    Pursuant to this Agreement, each of Aventis and
Guilford (in such capacity, the "Disclosing Party") have disclosed and will be
disclosing to the other party (in such capacity, the "Receiving Party") certain
proprietary information, technical data, trade secrets and know-how of the
Disclosing Party including, without limitation, Know-How, Product research and
plans, designs, methods, formulations, ingredients, samples, processes,
machines, processing and control information, Product performance data, manuals,
INDs, NDAs, Regulatory Filings, the content of any unpublished patent
applications, drawings, formulae, devices, structures, models, prototypes, data,
test results, photographs, film, techniques, apparatus, tapes, disks,
unpublished trademarks, trade names and copyrights, customer lists, supplier
lists, markets, operating methods and procedures, marketing distribution and
sales methods and systems, sales figures, projections, finances and other
business information.

                  9.1.2    The Receiving Party shall, during the term of this
Agreement, and for seven (7) years after the expiration or sooner termination of
the term of this Agreement, make no use of such confidential information except
(x) to advance the purposes of the Marketing Rights Agreement in accordance with
its provisions or (y) to advance the purposes of this Agreement in accordance
with its provisions, which purposes shall include the transition of the
development, commercialization and sale of the Product to Guilford from APPI and
Guilford's corresponding disclosure of such confidential information to
potential distributors, vendors of regulatory services and such other third
party agents as may be used by Guilford to develop, commercialize and sell the
Product. Each party shall use the same efforts to keep secret and prevent the
disclosure of such confidential information to third parties as it would use
with respect to its own confidential information.

                  9.1.3    Information disclosed by the Disclosing Party shall
remain the sole and absolute property of the Disclosing Party, subject to the
rights granted in this Agreement and the transactions contemplated herein,
including the transfer of certain information by APPI to Guilford hereunder and
the corresponding change in the nature of such information from the proprietary
and confidential information of APPI to the proprietary and confidential
information of Guilford. Nothing in this Agreement shall limit the use or
disclosure by a party of its own proprietary or confidential information,
including the information to be transferred by APPI to

RIGHTS REVERSION AGREEMENT             22
<PAGE>   23

Guilford hereunder which upon such transfer shall become the confidential and
proprietary information of Guilford.

                  9.1.4    The above restrictions on the use and disclosure of
information shall not apply to any information which: (a) is already known to
the Receiving Party at the time of disclosure, as demonstrated by competent
proof; (b) is or becomes generally available to the public other than through
any act or omission of the Receiving Party in breach of this Agreement; (c) is
acquired by the Receiving Party from a third party who is not, directly or
indirectly, under an obligation of confidentiality to the Disclosing Party with
respect to same; (d) is required to be disclosed pursuant to applicable law,
rule or regulation; (e) is required to be disclosed to government regulatory
authorities to obtain Regulatory Approval for the Product or to respond to a
regulatory or governmental inquiry concerning the Product; or (f) is developed
independently by the Receiving Party without use, direct or indirect, of
information that is required to be held confidential hereunder. In the event
that Confidential Information is required to be disclosed pursuant to subsection
(d) or (e) of this Section 9.1.4, the Receiving Party shall promptly inform the
Disclosing Party of the circumstances requiring disclosure of the information
prior to disclosure to afford the Disclosing Party an opportunity to seek an
appropriate protective order or other means of seeking confidential treatment
for such information.

         9.2      Permitted Disclosure. Notwithstanding the provisions of
Section 9.1 of this Agreement, APPI shall be permitted to disclose information
to its wholesalers and other direct customers as necessary to effectively market
and distribute the Product as provided in Section IV(A)2 of the Marketing Rights
Agreement until such provision is terminated pursuant to Section 8.1.2(b) of
this Agreement.

         9.3 Press Releases. Notwithstanding the provisions of Section 9.1 of
this Agreement, Section IV(A)(3) of the Marketing Rights Agreement relating to
the coordination of press releases and other public announcements by the parties
shall govern this Agreement and the Marketing Rights Agreement until such
provision is terminated pursuant to Section 8.1.2(c) of this Agreement. In
furtherance of the foregoing, APPI acknowledges that the transactions
contemplated by this Agreement are material to Guilford and Guilford has an
obligation to disclose such transactions, and that Guilford may in its sole
discretion issue a press release in the form set forth as Exhibit E hereto;
provided, however, that any other disclosure by any of the parties relating to
the transactions contemplated by this Agreement shall be subject to the prior
review and approval, not to be unreasonably withheld or delayed, of the other
parties. In addition, Guilford may issue press releases and make other public
statements with respect to the results of the First Surgery Trial, and
Guilford's analyses and conclusions with respect thereto, and Guilford's plans
for Regulatory Filings based thereon, subject to providing APPI a reasonable
prior opportunity to review and comment on any and all such releases and subject
to Guilford considering in good faith comments of APPI prior to such release;
provided, however, that Guilford's obligation to provide such opportunity to
APPI to review and comment shall terminate upon the termination of this
Agreement and, notwithstanding Section 9.5, shall not survive such termination.
In any such disclosures, Guilford will not purport to attribute any
interpretations of the First Surgery Trial to APPI or purport to represent APPI
or any of its Affiliates, without APPI's prior written consent. Either party may
use prior press releases issued

RIGHTS REVERSION AGREEMENT             23
<PAGE>   24

in accordance with this Section 9.3, or the content thereof, after the date of
such release without prior notice or approval from the other party.

         9.4      Use of Name. Neither party shall use the name of the other for
marketing, advertising, promotional claims without the prior written consent of
the other party. In communications with regulatory authorities, neither party
shall purport to attribute any statements to the other party or purport to
represent the other party without the prior written consent of the other party.

         9.5      Survival. The provisions of this Article 9 shall survive the
expiration or sooner termination of the term of this Agreement.

                                   ARTICLE 10
                                 INDEMNIFICATION

         In order to distribute among themselves the responsibility for claims
arising out of this Agreement, and except as otherwise specifically provided for
herein, the parties agree as follows:

         10.1     Guilford Indemnification Obligation. Each of GPI and GPI
Holdings, jointly and severally, shall defend, indemnify and hold Aventis, its
Affiliates, and their respective officers, directors, agents, employees and
shareholders (collectively, "Aventis Indemnitees") harmless, from and against,
any and all losses, obligations, liabilities, penalties and damages (including
but not limited to compensatory and punitive damages), costs and expenses
(including, reasonable attorneys' fees), which the Aventis Indemnitees may incur
or suffer, and all deficiencies, actions (including without limitation, any
proceedings to establish insurance coverage), claims, suits, legal,
administrative, arbitration, governmental or other proceedings or
investigations, and judgments, reasonable costs and expenses (including
reasonable legal fees) which any of them may face arising out of (i) any breach
by GPI or GPI Holdings of any representation or warranty made by GPI or GPI
Holdings in this Agreement or any breach by GPI or GPI Holdings in the
performance or observation of any covenant, agreement, obligation or provision
in this Agreement to be performed or observed by GPI or GPI Holdings; (ii) any
negligent or otherwise tortious act or omission by GPI or GPI Holdings in
connection with the performance or observation of any covenant, agreement,
obligation or provision in this Agreement to be performed or observed by GPI or
GPI Holdings; and (iii) the enforcement by the Aventis Indemnitees of their
rights under this Section 10.1.

         10.2     Aventis Indemnification Obligation. Aventis shall defend,
indemnify and hold each of GPI and GPI Holdings, its respective Affiliates, and
their respective officers, directors, agents, employees and shareholders
(collectively, "GPI Indemnitees") harmless, from and against, any and all
losses, obligations, liabilities, penalties, and damages (including but not
limited to compensatory and punitive damages), costs and expenses (including
reasonable attorneys' fees), which the GPI Indemnitees may incur or suffer, and
all deficiencies, actions (including, without limitation, any proceedings to
establish insurance coverage), claims, suits, legal, administrative,
arbitration, governmental or other proceedings or investigations, and judgments,
reasonable costs and expenses (including, reasonable legal fees) which any of
them may face arising out of (i) any breach by APPI or RPR Inc. of any
representation or warranty

RIGHTS REVERSION AGREEMENT             24
<PAGE>   25

made by APPI or RPR Inc. in this Agreement or any breach by APPI or RPR Inc. in
the performance or observation of any covenant, agreement, obligation or
provision in this Agreement to be performed or observed by APPI or RPR Inc.;
(ii) any negligent or otherwise tortious act or omission by APPI or RPR Inc. in
connection with the performance or observation of any covenant, agreement,
obligation or provision in this Agreement to be performed or observed by APPI or
RPR Inc.; (iii) the enforcement by the GPI Indemnitees of their rights under
this Section 10.2.

         10.3     General Provisions. If any action, claim, suit, proceeding or
investigation arises as to which a right of indemnification provided in this
Article 10 applies, the GPI Indemnitee or the Aventis Indemnitee, as the case
may be (the "Indemnified Party"), shall promptly notify the party obligated
under this Article 10 to indemnify the Indemnified Party (the "Indemnifying
Party") thereof in writing, and allow the Indemnifying Party and its insurers
the opportunity to assume direction and control of the defense against such
action, claim, suit, proceeding or investigation, at its sole expense, including
without limitation, the settlement thereof at the sole option of the
Indemnifying Party or its insurers to the extent that Indemnified Party's
liability is not thereby invoked. The Indemnified Party shall cooperate with the
Indemnifying Party and its insurer in the disposition of any such matter and the
Indemnified Party will have the right and option to participate in the defense
of any action, claim, suit, proceeding or investigation as to which this Article
10 applies, with separate counsel at its election and cost. If the Indemnifying
Party fails or declines to assume the defense of any such action, claim, suit,
proceeding or investigation within thirty (30) days after notice thereof, the
Indemnified Party may assume the defense thereof for the account and at the risk
of the Indemnifying Party. The Indemnifying Party shall pay promptly to the
Indemnified Party any losses, obligations, liabilities, penalties, damages,
judgments, reasonable costs and expenses (including reasonable legal fees) to
which the indemnity under this Article 10 relates, as incurred.

         10.4     Survival.  The provisions of this Article 10 shall survive the
expiration or sooner termination of the term of this Agreement.

                                   ARTICLE 11
                               TERM AND EXPIRATION

         11.1     Term. The term of this Agreement shall commence on the date
hereof and shall expire at the end of the six-month period following the
Transition Date. The expiration of this Agreement shall have no effect on any
transactions completed under this Agreement prior to such expiration and, for
example, any agreement terminated or amended by this Agreement shall remain so
amended or terminated upon the expiration of this Agreement.

         11.2     Survival. The following shall survive the expiration or sooner
termination of the term of this Agreement: (a) any payment obligations of the
parties under this Agreement accruing prior to the date of expiration or
termination, and (b) any other provision herein expressly surviving expiration
or termination or necessary to interpret the rights and obligations of the
parties in connection with the expiration or termination of the term of this
Agreement and those matters that expressly survive termination of the 1996 Stock
Purchase Agreement (as modified by this Agreement).

RIGHTS REVERSION AGREEMENT             25
<PAGE>   26

         11.3     Events of Default.

                  11.3.1   The occurrence of any one or more of the following
acts, events or occurrences shall constitute an "Event of Default" under this
Agreement: either party breaches any material provision of this Agreement, the
Marketing Rights Agreement, the Registration Rights Agreement, the 1996
Manufacturing and Supply Agreement or the 1996 Stock Purchase Agreement and
fails to remedy such breach or default within sixty (60) days after the receipt
of notice thereof.

                  11.3.2   Notwithstanding the foregoing Section 11.3.1, in the
event of a breach or default which cannot be remedied within such sixty (60) day
period (other than a failure to make payment as required herein), so long as the
breaching/defaulting party is using commercially reasonable efforts to remedy
such breach or default, an Event of Default shall not have occurred until four
(4) months after notice of such breach or default and only if such breach or
default is not cured during such period.

         11.4     Remedies.

                  11.4.1   Immediately upon the occurrence of any Event of
Default by Guilford pursuant to Section 11.3, Aventis shall have the right to
terminate this Agreement, exercisable by delivering written notice thereof to
Guilford, and to pursue any and all remedies available to it at law or in equity
including, without limitation, the right to seek to recover from Guilford any
and all damages and losses of any nature whatsoever (including, without
limitation, consequential damages, lost profits and direct damages).

                  11.4.2   Immediately upon the occurrence of any Event of
Default by Aventis pursuant to Section 11.3, Guilford shall have the right to
terminate this Agreement, exercisable by delivering written notice thereof to
Aventis, and to pursue any and all remedies available to it at law or in equity
including, without limitation, the right to seek to recover from Aventis any and
all damages and losses of any nature whatsoever (including, without limitation,
consequential damages, lost profits and direct damages).

         11.5     Force Majeure. The obligations of Guilford and Aventis
hereunder shall be subject to any delays or non-performance caused by: acts of
God, earthquakes, fires, floods, explosion, sabotage, riot, accidents;
regulatory, governmental or military action or inaction; strikes, lockouts or
labor trouble; perils of the sea; or failure or delay in performance by third
parties, including suppliers and service providers; or any other cause beyond
the reasonable control of either party. The party which is not performing its
obligations under this Agreement as a result of any such event of force majeure
shall use commercially reasonable efforts to resume compliance with this
Agreement as soon as possible.

                                   ARTICLE 12
                                  MISCELLANEOUS

         12.1     Further Assurances.  Guilford and Aventis will each, at and
after the Closing Date, without further consideration, do, execute, acknowledge,
deliver and file, or will cause to be done, executed, acknowledged, delivered
and filed, all such further acts, deeds, assignments,

RIGHTS REVERSION AGREEMENT             26
<PAGE>   27

transfers, conveyances, powers of attorney and assurances as may be reasonably
required (i) for transferring, conveying and assigning to Guilford, or to its
respective successors or assigns, the items to be transferred pursuant to
Article 6 hereof and (ii) to otherwise implement the transactions contemplated
by this Agreement.

         12.2     HSR Filings. Guilford and Aventis shall cooperate with one
another in (i) determining whether any filing of Notification and Report Forms
under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, is
required in connection with the consummation of the transactions contemplated by
the Transaction Agreements and (ii) preparing and making any such filing and
furnishing information required in connection therewith as soon as is reasonably
practicable, but in any event within five business days after the signing of
this Agreement. If such a filing is required, each party shall be responsible
for preparing and making its own filing and each party shall be responsible for
paying its own filing and other fees, costs and expenses associated with making
the filing.

         12.3     Independent Contractors. In making and performing this
Agreement, Guilford, on the one had, and Aventis, on the other hand, are acting
and shall act as independent contractors. Nothing in this Agreement shall be
deemed to create an agency, joint venture or partnership relationship between
Guilford, on the one hand, and Aventis, on the other hand. Neither Guilford nor
Aventis shall have the authority to obligate the other in any respect, and
neither Guilford nor Aventis shall hold itself out as having any such authority.
All personnel of GPI Holdings shall be solely employees of GPI Holdings and
shall not represent themselves as employees of GPI or Aventis. All personnel of
GPI shall be solely employees of GPI and shall not represent themselves as
employees of GPI Holdings or Aventis. All personnel of Aventis shall be solely
employees of Aventis and shall not represent themselves as employees of GPI or
GPI Holdings.

         12.4     Assignment. Neither Guilford nor Aventis may assign or
otherwise transfer any of its rights or obligations hereunder without the prior
written consent of the other parties hereto; provided, however, a party may
assign its rights and obligations hereunder to an Affiliate, provided that the
assigning party shall remain responsible for all obligations to the
non-assigning parties hereunder.

         12.5     Binding Effect; Benefits. This Agreement shall inure to the
benefit of and be binding upon the parties hereto and their respective permitted
successors and assigns. Nothing contained herein shall give to any other Person
any benefit of any legal or equitable right, remedy or claim.

         12.6     Amendments.  This Agreement may be modified, amended or
supplemented only by an instrument in writing executed by each of Guilford and
Aventis.

         12.7     Waivers. No term or provision hereof will be considered waived
by any party, and no breach excused by any party, unless such waiver or consent
is in writing signed on behalf of the party against whom the waiver is asserted.
No consent by any party to, or waiver of, a breach by any party, whether express
or implied will constitute a consent to, waiver of, or excuse of any other,
different or subsequent breach by any party.

RIGHTS REVERSION AGREEMENT             27
<PAGE>   28

         12.8     Notices. All notices, claims, certificates, requests, demands
and other communications hereunder shall be in writing and shall be delivered
personally or sent by facsimile transmission, nationally-recognized express
courier, or United States registered or certified mail, return receipt
requested, addressed as follows:

         If to GPI to:

         Guilford Pharmaceuticals Inc.
         6611 Tributary Street
         Baltimore, Maryland  21224
         Attention: Secretary
         Fax: 410-631-6819

         If to GPI Holdings to:

         GPI Holdings, Inc.
         222 Delaware Avenue
         P.O. Box 2306
         Wilmington, Delaware 19899
         Attention: President
         Fax: 302-888-6865

RIGHTS REVERSION AGREEMENT             28
<PAGE>   29

         If to APPI to:

         Aventis Pharmaceuticals Products Inc.
         Route 202-206
         Bridgewater, New Jersey 08807
         Attention:  Senior Vice President, Corporate Development
         Fax:  908-231-3619

         With a copy to:

         Aventis Pharmaceuticals Products Inc.
         Route 202-206
         Bridgewater, New Jersey 08807
         Attention:  Vice President, Legal Corporate Development
         Fax:  908-231-2243

         If to RPR Inc. to:

         Rhone-Poulenc Rorer Inc.
         C/o Aventis Pharmaceuticals Products Inc.
         Route 202-206
         Bridgewater, New Jersey 08807
         Attention:  Senior Vice President, Corporate Development
         Fax:  908-231-3619

         With a copy to:

         Aventis Pharmaceuticals Products Inc.
         Route 202-206
         Bridgewater, New Jersey 08807
         Attention:  Vice President, Legal Corporate Development
         Fax:  908-231-2243

or to such other address as the party to whom notice is to be given may have
furnished to the other parties in writing in accordance herewith. Any such
communication shall be deemed to have been received (i) when delivered, if
delivered personally, (ii) when sent (with confirmation received), if sent by
facsimile transmission prior to 5:00 p.m. on a business day, (iii) on the first
business day after dispatch (with confirmation received), if sent by facsimile
transmission on a day other than a business day or after 5:00 p.m. on a business
day; (iv) upon the date of delivery indicated in the records of such courier, if
sent by courier; or (v) upon the date of delivery indicated on the return
receipt, if sent by United States certified or registered mail.

         12.9     Counterparts.  This Agreement shall become binding when any
two or more counterparts hereof, individually or taken together, shall bear the
signatures of each of the parties hereto. This Agreement may be executed in any
number of counterparts, each of which shall be

RIGHTS REVERSION AGREEMENT             29
<PAGE>   30

deemed an original as against the party whose signature appears thereon, but all
of which taken together shall constitute but one and the same instrument.

         12.10    Headings. The article and section headings contained in this
Agreement are for reference purposes only and shall not affect in any way the
meaning or interpretation of this Agreement.

         12.11    Governing Law. This Agreement, and any claims, disputes or
causes of action relating to or arising out of this Agreement, shall be
construed in accordance with and governed by the laws of the State of Delaware,
without giving effect to the conflict of laws principles thereof.

         12.12    Severability. Any of the provisions of this Agreement which
are determined to be invalid or unenforceable in any jurisdiction shall be
ineffective to the extent of such invalidity or unenforceability in such
jurisdiction, without rendering invalid or unenforceable the remaining
provisions hereof or affecting the validity or enforceability of any of the
provisions of this Agreement in any other jurisdiction.

         12.13    Exhibits. The following Exhibits are attached to this
Agreement and made a part of this Agreement:

<TABLE>
<CAPTION>
         Exhibit           Description of Exhibit
         -------           ----------------------
<S>                        <C>
         A                 Registration Rights Agreement
         B                 Stock Purchase Agreement
         C                 APPI NDA and IND Transfer Information and Forms
         D                 Guilford NDA and IND Transfer Information and Forms
         E                 Guilford Press Release
</TABLE>

         12.14    Disputes.

                  12.14.1  Notwithstanding anything contained in this Agreement
to the contrary, if any dispute arises between the parties relating to or
arising out of this Agreement, appropriate representatives of the parties shall
first use commercially reasonable efforts to negotiate in good faith a
resolution of the dispute as expeditiously as is reasonably practicable.

                  12.14.2  If such representatives of the parties are unable to
resolve the dispute within seven (7) business days after each party has been
apprised of the dispute, any party shall have the right, exercisable by
delivering written notice thereof to the other parties, to refer the dispute to
the Chief Executive Officer of GPI and the Senior Vice President of Corporate
Development of Aventis. If any party exercises such right, such officers shall
use commercially reasonable efforts to negotiate in good faith a resolution of
the dispute as expeditiously as is reasonably practicable.

                  12.14.3  If the dispute is not resolved within 20 business
days after the date that a party referred the matter to the Chief Executive
Officer of GPI and the Senior Vice President of Corporate Development of Aventis
(or such other period of time as the parties may mutually agree), each party
shall have the right to initiate and pursue any remedy available to it

RIGHTS REVERSION AGREEMENT             30
<PAGE>   31

at law or in equity; provided, however, that all claims, disputes or causes of
action relating to or arising out of this Agreement shall be brought, heard and
resolved solely and exclusively by and in a federal or state court situated in
Wilmington, New Castle County, Delaware. Each of the parties hereto agrees to
submit to the jurisdiction of such courts and that such courts are a proper
venue for resolving all claims, disputes or causes of action relating to or
arising out of this Agreement.

         12.15    Entire Agreement. This Agreement, the Registration Rights
Agreement, the Marketing Rights Agreement, the Stock Purchase Agreement, the
1996 Manufacturing and Supply Agreement and the 1996 Stock Purchase Agreement,
constitute the entire agreement between the parties relating to the subject
matter of this Agreement and supersede all prior or simultaneous
representations, discussions, negotiations and agreements relating to such
subject matter, whether written or oral.

                           [Execution Page to Follow]

RIGHTS REVERSION AGREEMENT             31
<PAGE>   32

         IN WITNESS WHEREOF, duly authorized representatives of the parties
hereto have duly executed this Agreement as of the date hereof.

                                    AVENTIS PHARMACEUTICALS PRODUCTS INC.

                                    By:    /s/ Michael A. Yeomans
                                           -------------------------
                                    Name:  Michael A. Yeomans
                                    Title: Vice President

                                    RHONE-POULENC RORER INC.

                                    By:    /s/ Charles D. Dalton
                                           -------------------------
                                    Name:  Charles D. Dalton
                                    Title: Vice President

                                    GUILFORD PHARMACEUTICALS INC.

                                    By:    /s/ Craig R. Smith, M.D.
                                           ---------------------------
                                    Name:  Craig R. Smith, M.D.
                                    Title: Chairman of the Board, President and
                                            Chief Executive Officer

                                    GPI POLYMER HOLDINGS, INC.
                                    (formerly named GPI Holdings, Inc.)

                                    By:    /s/ Daniel P. McCollom
                                           -------------------------
                                    Name:  Daniel P. McCollom
                                    Title: Vice President

RIGHTS REVERSION AGREEMENT             32<PAGE>   1

                                                                   EXHIBIT 10.62

                                    AGREEMENT

         This AGREEMENT ("Agreement") is dated as of October 24, 2000 by and
between Cardinal Health Sales and Marketing Services ("Vendor"), a division of
RedKey, Inc., an Ohio corporation, with its principal place of business at 7000
Cardinal Place, Dublin, Ohio, and Guilford Pharmaceuticals Inc. ("Company"), a
Delaware corporation having a principal place of business at 6611 Tributary
Street, Baltimore MD 21224.

                             BACKGROUND INFORMATION
         Company develops, distributes and sells pharmaceutical products, and
Vendor provides medical representatives who Detail (as hereinafter defined)
pharmaceutical products for third parties. The Company desires Vendor to provide
representatives to Detail certain products as determined and directed by Company
in the Territory (as hereinafter defined), pursuant to the terms and conditions
of this Agreement, and Vendor desires to provide the Representatives and perform
such services pursuant to the terms and conditions set forth in this Agreement.

         The parties hereby agree as follows:

                                    ARTICLE I
                      DEFINITIONS AND REFERENCES TO VENDOR

         1.1.     Definitions.  The following terms when used in this Agreement
shall, except where the context otherwise requires, have the following meanings:

                  (a)      "Act" means the Federal Food, Drug and Cosmetic Act,
as amended, and the regulations promulgated thereunder from time to time.

                  (b)      "Affiliate" shall have the definition set forth in
Rule 405 promulgated under the Securities Act of 1933, as amended.

                  (c)      "Agency" means any governmental regulatory authority
in the Territory responsible for granting approvals for the sale or maintaining
regulatory oversight of the Products, including, without limitation, the FDA (as
hereinafter defined).

                  (d)      "Contract Year" means a period of twelve (12)
consecutive months during the term of this Agreement, beginning on the Effective
Date (as hereinafter defined).

                  (e)      "Detail" means an interactive, face-to-face visit by
a Representative with a Target Customer (as hereinafter defined) or his or her
legally empowered designee in the Territory, during which the FDA-approved
indicated uses, safety, effectiveness, contraindications, side effects, warnings
and other relevant characteristics of the Product (as hereinafter defined) is
described by the Representative in a fair and balanced manner consistent with
the requirements of the Act, and using, as necessary or desirable, the Product
Labeling (as hereinafter defined) and the Product Promotional Materials (as
hereinafter defined).

                                       1
<PAGE>   2

                  (f)      "Effective Date" means the date this Agreement is
fully executed by both parties.

                  (g)      "FDA" means the United States Food and Drug
Administration and any successor agency having substantially the same functions.

                  (h)      "Manager" means an individual hired by and retained
as an employee of Vendor to supervise activities of Representatives under this
Agreement, including district sales managers, regional sales directors, a
national sales director, and a project manager.

                  (i)      "PDMA" means the Prescription Drug Marketing Act of
1987, as amended, and the regulations promulgated thereunder from time to time.

                  (j)      "Product Detail" means Detail of a Product between
Target Customer and Representative. When used as a verb, "Detail" or "Detailing"
shall mean to engage in a Detail as defined in this Section 1.l(e).

                  (k)      "Product Labeling" means all labels and other
written, printed, or graphic matter provided by the Company including (i) any
container or wrapper utilized with a Product, or (ii) any written material
accompanying a Product, including, without limitation, Product package inserts.

                  (l)      "Product Launch Date" means the first Monday
following completion of the Training Program (as defined in Section 6.1).

                  (m)      "Product Promotional Materials" means all written,
printed or graphic material provided by the Company, including Product Labeling,
intended for use by Representatives during a Detail, including visual aids, file
cards, premium items, clinical studies, reprints, drug information updates and
any other promotional support items that Company deems necessary or appropriate
to conduct the Program. Product Promotional Materials shall include FDA approved
indicated uses, safety, effectiveness, contraindications, side effects, warnings
and other relevant characteristics of each of the Products.

                  (n)      "Products" means the pharmaceutical products to be
detailed by Representatives and marketed by Company as set forth on attached
Schedule 1.1(l) and such other products as may be mutually agreed between the
parties and added to Schedule 1.1(l).

                  (o)      "Program" means the program of Detailing to be
conducted by the Representatives pursuant to this Agreement and during the term
of this Agreement, as defined in Section 14.1.

                  (p)      "Representative" and "Representatives" mean an
individual hired by and retained as an employee of Vendor to conduct Detailing
of Products in connection with the Program. As sometimes used herein,
Representative shall also include Managers.

                                       2
<PAGE>   3

                  (q)      "Target" or "Target Customer" means a physician or
other specialist identified by Company.

                  (r)      "Territory" means the geographical area specified in
the attached Schedule 1.1(p).

                  (s)      "Vendor" means Cardinal Health Sales and Marketing
Services, a division of RedKey, Inc., an Ohio corporation. References herein to
Vendor shall be deemed to include the Representatives and Managers.

                                   ARTICLE II
               APPOINTMENT OF VENDOR; GENERAL SCOPE OF ACTIVITIES

         2.1.     Furnishing Representatives. Vendor shall recruit and hire,
within twelve (12) weeks after the Effective Date, at least twenty (20), or such
greater number of Representatives (not to exceed thirty (30)) as shall be
designated by Company within five (5) weeks of the Effective Date, to engage in
Product Detail activities in the Territory. Such Representatives shall conform
to the Representatives Profile set forth on Schedule 2.1. Vendor shall assign
Representatives for such Target Customers, in such numbers, and in such
Territories as shall be designated by Company (or recommended by Vendor pursuant
to Section 2.9) during the term of this Agreement. Each Representative shall
make Product Details on his or her assigned Target Customers based on the
general direction given by Company's designated management team and as mutually
agreed to by Vendor. The duties of such Representatives shall be exclusively to
Detail the Products and perform other related activities deemed necessary for
the establishment and maintenance of new and existing customers of the Products
in the Territory defined as set forth on Schedule 1.1(p). Company shall at all
times retain the right to promote the Products by whomever, wherever and to
whomever it chooses.

         2.2      Furnishing Managers. Vendor shall recruit and hire Managers to
supervise the activities of Representatives and to perform this Agreement in
such numbers and for such Territories (when relevant) as mutually agreed upon by
Vendor and Company.

         2.3.     Scope of Activities.  The parties shall perform the following
activities as applicable to each in connection with the Program:

                  (a)      Vendor will recruit, interview and hire as its
employees Representatives and Managers conforming to the Representatives Profile
set forth on Schedule 2.1. Vendor shall have the sole authority to reject any
applicant for employment as a Representative or Manager. Company may, at its
sole cost and expense, participate with Vendor in the interviewing of Managers,
and the Company shall have the right to approve the hire of Managers, and may
nominate acceptable Managers for consideration for the Vendor to hire; provided,
however, that in the event Vendor rejects an applicant for Manager and
thereafter hires such applicant at the request of Company, Company shall
indemnify for and hold Vendor harmless from any Damages (as defined in Section
16.1) arising as a result of such Manager's wrongful or negligent acts or
omissions.

                                       3
<PAGE>   4

                  (b)      Vendor shall have sole and exclusive authority to
discipline or terminate the employment of Representatives and the Managers.
Company may reasonably request that a Representative or Manager be terminated or
reassigned if such Representative's or Manager's activities or conduct are not
adequately achieving the performance goals of the Product, or if the
Representative or Manager fails to comply with all applicable laws, regulations,
and Company requirements for Detailing the Product. Reassignment in this context
under this Agreement may mean reassignment to another part of the Territory, or
reassignment to another contract sales force for another Vendor account. Vendor
shall use its best efforts to comply with such request; provided that such
action complies with applicable laws and is in accordance with Vendor's policies
and procedures as determined by Vendor. In the event Vendor determines that its
policies and procedures or applicable laws prohibit the termination or
reassignment of any Representative so requested by Company, it shall notify
Company of such determination and submit a corrective action plan for Company
approval.

                  (c)      Vendor shall cause each Representative to attend and
successfully complete the Training Program (as defined in Section 6.1) conducted
jointly by Company or its agents and Vendor for each of the Products prior to
participating in the Program. Any such Representative who shall not successfully
complete all such requirements shall be removed and replaced by another
Representative who shall comply with such requirements.

                  (d)      Vendor shall from time to time and in any case every
six (6) weeks if so requested by Company, beginning with the Product Launch Date
conduct random profiles of activities during the Program consisting of
satisfaction surveys sent to customers with whom Representatives have interacted
and share the results of such profiles with Company on a regular and prompt
basis. Vendor shall reasonably assist the Company should Company decide to
conduct such random profiles itself.

                  (e)      Vendor's District Managers shall, as part of their
activities under this Agreement, routinely accompany Representatives on Details,
conduct field evaluations of the Representatives and the Program, including time
supervision, territory management, and reporting, and be available to review
such evaluations with the Company's coordinator of the Program. At Company's
request, Vendor shall permit Company or its designated representative to review
Vendor's evaluations relating to the foregoing and to accompany the
Representatives on such Details.

                  (f)      Company shall provide Vendor, without cost,
sufficient quantities of the Product Promotional Materials and Product Labeling
for the performance and supervision of Detailing. Company shall be solely
responsible for the preparation, content, and method of distribution of the
Product Promotional Materials and the Product Labeling. In connection with the
Detailing of the Products, the Representatives shall use only the Product
Labeling and the Product Promotional Materials provided by Company; and under no
circumstances shall Vendor or the Representatives develop, create, or use any
other promotional material or literature for the Detailing of the Products.
Company shall advise Vendor immediately of any inaccuracy or incompleteness of
the Product Promotional Materials or the Product Labeling, and upon such notice
Vendor and the Representatives shall immediately cease the use of any portion or
all of the Product Promotional Materials or Product Labeling so identified by
Company.

                                       4
<PAGE>   5

                  (g)      Vendor shall instruct the Representatives to limit
their verbal statements and claims regarding the Products, including efficacy
and safety, to those that are consistent with the Product Labeling and the
Product Promotional Materials. The Representatives shall not add, delete, or
modify claims of efficacy or safety in the Detailing of the Products, nor make
any changes (including underlining or otherwise highlighting any language or
adding any notes thereto) in the Product Promotional Materials. Representatives
shall not make any disparaging, untrue, or misleading statements about any of
Company or its Affiliates, employees, competitors, or competing products.
Representatives shall Detail the Products in strict adherence to all applicable
laws, regulations, and professional requirements, including, but not limited to,
the Act, the Medicare and Medicaid Anti-Kickback Statute, and the American
Medical Association Gifts to Physicians from Industry Guidelines.

                  (h)      The Representatives shall remain under the direct
authority and control of Vendor, but shall cooperate with Company and shall
receive advice and direction related to Detail activities on the Products from
Company and Vendor mutually. Company shall make all decisions with respect to
the overall strategy in connection with the Detailing of the Products. Any
Company personnel interacting with Vendor Representatives shall not discipline
the Representatives or implement terms or conditions of employment or personnel
policies and/or practices with respect to the Representatives or otherwise
control the daily activities of Representatives. Company shall use commercially
reasonable efforts to advise Vendor, and to the extent necessary, to share with
Vendor copies of reports, memoranda, and other data relating to Company's
observations or assessment of the Representative's performance under this
Agreement.

                  (i)      Vendor shall supply Representatives and Managers with
fleet vehicles for their use in performing and supervising the Detailing, and
Company shall reimburse Vendor for all of its reasonable, budgeted, documented
out-of-pocket costs related to such vehicles, including but not limited to costs
related to owning, leasing, maintaining, insuring, and/or operating such
vehicles (including fuel costs). Company shall reimburse Vendor for all
reasonable, budgeted, documented out-of-pocket costs and expenses (i.e., airline
tickets and other travel expenses, hotel, rent-a-car, business meals, travel
meals, etc.) of Representatives and Managers in connection with performing
services pursuant to this Agreement. Company and Vendor shall establish a
mutually acceptable budget for the costs and expenses referenced in this
subparagraph for each Territory, and Vendor shall obtain prior approval for any
such costs or expenses that exceed the budget. All such costs and expenses in
excess of such budget shall be for the Vendor's account, unless Company agrees
otherwise.

                  (j)      Company and Vendor shall work together, using their
respective proprietary databases, to establish a database of Target Customers in
the Territory. Company and Vendor shall confer throughout the term of the
Agreement regarding additions to and deletions from the Target Customer
database. Company.

                  (k)      Representatives and Managers shall comply with
Vendor's drug policy, a copy of which is attached hereto and incorporated by
reference herein as Schedule 2.3(k).

                                       5
<PAGE>   6

         2.4.     Orders for Products. Company shall be solely responsible for
establishing the terms and conditions of the sale of the Products, including
without limitation, the price at which the Products will be sold, whether sales
of the Products will be subject to any discounts, the method of distribution of
the Products, and whether any credit will be granted or refused in connection
with the sale or return of any Product. Company shall be exclusively responsible
for accepting and filling all purchase orders for the Products, billing and
returns for the Products, and all other activities in connection with the sale
and delivery of the Products, other than Detailing. If Vendor or the
Representatives receive an order for the Products, they shall immediately
transmit such order to Company for further handling and communications with the
submitter of the order, including acceptance or rejection, which shall be in
Company's sole discretion.

         2.5.     Representatives' Activity. Subject to Company's obligations
and representations and warranties in this Agreement, any negligent or wrongful
act or omission on the part of the Representatives (both individually and as a
group) that occur during the term of this Agreement and that arise during the
course and within the scope of their employment with Vendor pursuant to this
Agreement shall be deemed to be negligent or wrongful acts or omissions of
Vendor; provided, however, that any acts or omissions of the Representatives
pursuant to the direction, control or supervision of Company or its employees or
agents shall not be deemed to be negligent or wrongful acts or omissions of
Vendor. Wrongful acts or omissions shall include in this context under this
Agreement failure to comply with applicable laws and regulations or Vendor's
policies and procedures or Companies policies and procedures that have been
communicated in writing to Vendor and the Representative. Each party shall
notify the other in writing as promptly as practicable of any such material
alleged negligent or wrongful acts or omissions on the part of the
Representatives of which it becomes aware along with a plan to remedy such acts
or omissions, and Company shall provide Vendor with a reasonable opportunity to
remedy such acts or omissions, and if indicated, to replace the involved
Representatives.

         2.6      Performance Appraisal. From time to time at Company's request
and in any case at 3 months and 6 months after the Product Launch Date, and
every six (6) months thereafter, Vendor and Company shall jointly conduct a
performance appraisal of each Representative. Without limiting its rights under
this Agreement, including Section 2.3(b) and Section 2.5, Company shall have the
right to request the reassignment of any Representative who is achieving less
than 80% of the sales targets established for that Representative for a given
quarter. From time to time at Company's request, Vendor shall make available to
Company for review the primary call data and records.

         2.7      Vacancies/Turnover. In the event of a Representative vacancy
due to resignation, reassignment, termination or hiring by the Company pursuant
to Section 3.3 of a Representative, Vendor shall, at Company's request, use its
best efforts to fill any such vacancy within a four (4) week period. All
recruiting and other related expenses for filling a vacancy shall be borne by
Vendor; provided, however, that Company shall reimburse Vendor all recruiting
and other related expenses for filling any vacancy occurring pursuant to
Company's request for reassignment or termination other than: (i) a request
pursuant to the last sentence of Section 2.5, the penultimate sentence of
Section 2.6, or Section 14.7; (ii) due to the Representative's failure

                                       6
<PAGE>   7

to conform (or to continue to conform) to the Representatives Profile set forth
in Schedule 2.1; or (iii) due to the failure of the Representative to Detail in
conformity with applicable law or regulations, or to follow Vendor's policies
and procedures. If Company desires to interview any candidates, Company shall
bear its own cost of attending any final interview conducted by Vendor or the
costs of any separate interview arranged for by Company.

         2.8      Adjustments to Number of Representatives. No more than every
six (6) months, Company may initiate a review by the parties of the adequacy or
appropriateness of the number of Representatives, and may designate plans, to be
instituted over a period of no longer than ninety (90) days, for an increase or
decrease in the number of Representatives based on the market performance of the
Product, the Detailing of the Product by Representatives who may be hired by
Company as contemplated in Section 3.3 or other parties, or other factors,
provided that Vendor may, upon thirty (30) days prior written notice, terminate
this Agreement in the event that the total number of Representatives under this
Agreement reaches ()twenty (20) Representatives, with no vacancies authorized to
be filled by Company.

         2.9      Territory Design. At the request of Company, Vendor shall
design and implement (or redesign and re-implement) a Territory design
(including sizing, deployment, alignment and mapping) of Representatives which
Vendor recommends as optimal for the Detailing of the Products (for the fee set
forth in Schedule 3.1. D, attached hereto).

                                   ARTICLE III
                                  COMPENSATION

         3.1.     Amount and Time of Payment.

                  (a)      For services hereunder, Company shall pay to Vendor
the fees set forth in Schedule 3.1 attached hereto and incorporated by reference
(the "Services Fee"), which shall be payable as follows:

<TABLE>
<CAPTION>
                  Time Period - Contract Year                         Payment Amount
                  ---------------------------                         --------------
<S>               <C>                                                 <C>
                  1st Contract Year                                   A total of $2,000,000.00,
                                                                      payable in twelve equal
                                                                      monthly installments of
                                                                      $166,666.66.

                  2nd Contract Year                                   Service Fees, plus the
                                                                      Deferred Fees (as hereinafter
                                                                      defined).

                  3rd Contract Year                                   Service Fees, plus the
                                                                      Deferred Fees (as hereinafter
                                                                      defined).
</TABLE>

                  At the conclusion of the first Contract Year, Vendor and
Company shall calculate the actual Service Fee for that first contract year. The
"Deferred Fees" shall be the amount of the first year Service Fee plus any other
amount due under this Agreement less the $2,000,000.00 payment

                                       7
<PAGE>   8

                           (i)      The Deferred Fees shall be repaid by Company
over the second (2nd) and third (3rd) Contract Years, provided Company is not in
breach of this Agreement and the Agreement remains in full force and effect.
Company shall pay the Deferred Fees in equal monthly installments of principal
plus accrued Interest, beginning on the first day of the thirteenth (13th) month
of the Agreement and continuing on the first (1st) day of each calendar month
thereafter until all outstanding principal and accrued interest has been paid in
full, which in no event shall exceed the first day of the thirty-sixth (36th)
month of this Agreement.

                           (ii)     The Deferred Fees shall accrue interest
beginning the first day of Contract Year two (2) at the rate of the 3-month
LIBOR plus 175 basis points, adjusted quarterly ("Interest").

                  (b)      Vendor shall submit monthly invoices to Company for
all Service Fees and any other amounts due under this Agreement and Company
shall pay such amounts within thirty (30) days of the invoice date.

                  (c)      Notwithstanding any other right or remedy, in the
event of Company's default or a breach of this Agreement and failure of Company
to cure same within fifteen (15) days of notice to such effect by Vendor, all
unpaid principal and accrued but unpaid interest shall be accelerated and
immediately due and payable by Company.

                  (d)      Without limiting Vendor's rights under law or equity,
Vendor and its Affiliates, parent or related entities, may exercise a right of
set off against Company for any and all amounts due under this Agreement
including, but not limited to, the Deferred Fees, against any amounts owed to
Company by Vendor, or its Affiliates, parent, or related entity, if , during the
term of this Agreement, Company defaults on any of its loan covenants with its
third party lenders, or their assignees, which default remains uncorrected for a
period of ten (10) days beyond any applicable cure period.

                  (e)      If this Agreement is terminated prior to expiration
of the Initial Term, all Deferred Fees shall become immediately due and payable
by Company.

                  (f)      In the event the duration of this Agreement is
extended for the Renewal Term, as defined in Section 14.1, Company shall pay
Vendor a Service Fee for the Renewal Term as further negotiated by the parties.

         3.2.     Early Termination Fee. If during the first 12 months following
the Effective Date, Vendor terminates this Agreement pursuant to Sections 2.8,
14.2, 14.3, 14.6 or 14.7, or Company terminates this Agreement pursuant to
Sections 14.4 or 14.7, Company shall pay Vendor, as reimbursement for Vendor's
expenses in preparing to perform and performing this Agreement, as well as for
Vendor's expectancy interest under this Agreement, a fee equal to the amount set
forth on Schedule 3.2 attached hereto (the "Early Termination Fee"). Company and
Vendor acknowledge that Vendor's damages upon termination of this Agreement
would be difficult to ascertain and not susceptible of ready proof, and that the
Early Termination Fee is

                                       8
<PAGE>   9

agreed to as a reasonable estimation of Vendor's damages upon early termination
of the Agreement, and not as a penalty.

         3.3.     Company's Hiring of Representatives or Managers.

                  (a)      Company acknowledges that Vendor has incurred or will
incur costs and expenses in connection with recruiting, hiring, and training the
Representatives and Managers. During the term of this Agreement, in the event
Company hires as its own employee or as an independent contractor or agent any
one or more of the Representatives, Company shall pay Vendor the fee(s) set
forth in the attached Schedule 3.3. The provisions of this Section 3.3(a) shall
not apply to any Representatives hired by Vendor who were employees of Company
as of the date of this Agreement.

                  (b)      Beginning twelve (12) months following the Effective
Date for Representatives and beginning six (6) months following the Effective
Date for Managers, Company shall have the right to identify those
Representatives or Managers, that Company desires to hire (collectively, the
"Targeted Employees") and to negotiate with any Targeted Employee concerning the
terms on which Company might hire that Targeted Employee. Vendor agrees not to
interfere with the Company's solicitation and hiring of the Targeted Employees ,
and Vendor will assist Company in the transition of Targeted Employees from
Vendor to Company, provided, however, that in the event such Targeted Employer
declines employment with Company, then Vendor shall have the right to discuss
other employment opportunities with such Targeted Employer that would commence
after expiration of the Term of the Agreement and any renewal. For a period of
twelve months after any termination of this Agreement, Vendor agrees not to
solicit for hire as an employee, agent or independent contractor any Targeted
Employee hired by Company during the term of this Agreement.

         3.4.     Reimbursement of Expenses. Except as provided in Section
3.1(a), all expenses of Vendor for which Company is obligated to reimburse
Vendor under this Agreement, including but not limited to travel expenses and
vehicle expenses under Section 2.2(i), shall be paid by Company within 30 days
after Vendor has submitted a statement itemizing such expenses. Vendor shall use
its best efforts to submit such expense statements to Company monthly.

         3.5      Past Due Amounts. Failure of the Company to timely make any
payment to Vendor under this Agreement within fifteen (15) days of the due date
will constitute a material breach of this Agreement by Company. All amounts
owing by Company to Vendor pursuant to this Agreement that are not timely paid
by Company will bear interest at the rate of 10% per annum from the due date.

         3.6      Bonus Potential.

                  (a)      Upon execution of this Agreement and no later than
each anniversary of the Effective Date, Company and Vendor shall use good faith
efforts to jointly determine or revise, as the case may be, unit sales forecast
(the "Unit Sales Forecast") for each year following the Product Launch Date
during the Initial Term and any Renewal Term (each such year, a "Detailing
Year") for the purpose of evaluating the Representatives and determining
eligibility

                                       9
<PAGE>   10

for a potential Bonus. The Bonus for a given Detailing Year will be based upon
Actual Unit Sales over the Forecasted Unit Sales, as further set forth on
Schedule 3.6 attached hereto, as the same may be amended by the written
agreement of the parties from time to time.

                  (b)      Company shall reimburse Vendor for the Bonus for any
Representative actually paid by Vendor to the Representative in accordance with
Schedule 3.6 no later than sixty (60) days following the close of a Detailing
Year relating to which such Bonus was paid.

                                   ARTICLE IV
                    REPRESENTATIONS, WARRANTIES AND COVENANTS

         4.1.     By Vendor. Vendor represents, warrants, and covenants to
Company, as of execution of this Agreement and during the term of this
Agreement, as follows:

                  (a)      that Vendor and the Representatives shall perform the
Detailing in a professional, timely, competent and efficient manner;

                  (b)      that Vendor shall comply with all laws, rules and
regulations that apply to the performance of services under this Agreement,
including but not limited to the PDMA, the Medicare and Medicaid Anti-Kickback
Act (42 U.S.C. Section 1320a-7b(a)), the Civil False Claims Act (31 U.S.C.
Section 3729(a)), Sections 1128A, 1128B, and 1877 of the Social Security Act (42
U.S.C. Sections 1320a-7a, -7b, and 1395nn), the Health Care Fraud Act (18 U.S.C.
Section 1347), and the Criminal False Claims Act (18 U.S.C. Section 287), as
amended from time to time, as well as similar applicable state laws;

                  (c)      when on Company's premises or on the premises of
Company's customers, Vendor and the Representatives shall comply with all of
Company's or Company's customer's policies regarding the conduct of visitors of
which Vendor and the Representatives are aware, a copy of which Vendor
acknowledges receiving;

                  (d)      that the Representatives and Managers shall be
exclusively assigned to Detailing and supervision of the Detailing of the
Products, and no other activities unrelated to the Program;

                  (e)      that Vendor is under no obligation to any third party
that would prevent the execution of this Agreement or interfere with its
performance under this Agreement;

                  (f)      That Vendor is a corporation duly incorporated,
validly existing and in good standing under the laws of the State of Ohio; and

                  (g)      That Vendor has the full right, power and authority
to execute, deliver and perform this Agreement and that this Agreement has been
duly executed and delivered by Vendor and constitutes its legal, valid and
binding obligation, enforceable in accordance with its terms.

                                       10
<PAGE>   11

         4.2.     By Company. Company represents, warrants, and covenants to
Vendor, as of execution of this Agreement and during the term of this Agreement,
as follows:

                  (a)      that Company is under no obligation to any third
party that would prevent the execution of this Agreement or interfere with its
performance under this Agreement;

                  (b)      that Company shall comply with all laws, rules and
regulations that apply to the Products and their sale, the Program, and this
Agreement, including but not limited to the Act, the PDMA, the Medicare and
Medicaid Anti-Kickback Act (42 U.S.C. Section 1320a-7b(a)), the Civil False
Claims Act (31 U.S.C. Section 3729(a)), Sections 1128A, 1128B, and 1877 of the
Social Security Act (42 U.S.C. Sections 1320a-7a, -7b, and 1395nn), the Health
Care Fraud Act (18 U.S.C. Section 1347), and the Criminal False Claims Act (18
U.S.C. Section 287), as amended from time to time, as well as similar applicable
state laws;

                  (c)      that the Product Labeling and Product Promotional
Materials are accurate, complete, and in compliance with the Act and all rules
and regulations of the FDA;

                  (d)      that, subject to FDA approval, the Products may be
lawfully Detailed and sold;

                  (e)      that Company is a corporation duly incorporated,
validly existing and in good standing under the laws of the State of Delaware;
and

                  (f)      that Company has the full right, power and authority
to execute, deliver and perform this Agreement and that this Agreement has been
duly executed and delivered by Company and constitutes its legal, valid and
binding obligation, enforceable in accordance with its terms.

                                    ARTICLE V
                    STATUS OF VENDOR AND THE REPRESENTATIVES

         5.1.     Vendor Independent Contractor. Vendor is being retained and
shall perform hereunder strictly as an independent contractor. Representatives
and Managers of Vendor performing services hereunder shall not be, and shall not
be considered to be, employees of Company for any purpose, and shall at all
times remain employees of Vendor, subject to Section 3.3. Neither party shall
have any responsibility for the hiring, termination, compensation, benefits or
other conditions of employment of the other party's employees, except as
otherwise provided in this Agreement.

         5.2.     No Company Benefits. While employees of Vendor, the Managers
and Representatives are not eligible to participate in any benefits programs or
sales bonuses offered by Company to its employees, or in any pension plans,
profit sharing plans, insurance plans or any other employee benefit plans
offered from time to time by Company to its employees, provided that the
Representatives shall be eligible to participate in Company sales contests if so
requested by Company and approved by Vendor, and former employees of Company
hired by Vendor shall not be required to forfeit any Company benefits. Vendor
acknowledges and agrees

                                       11
<PAGE>   12

that Company does not, and will not, maintain or procure any worker's
compensation or unemployment compensation insurance for or on behalf of the
Managers or Representatives while they are employees of Vendor. Vendor
acknowledges and agrees that it shall be solely responsible for paying all
salaries, wages, benefits and other compensation which its employees (including
Representatives and Managers) may be entitled to receive in connection with the
performance of the services hereunder. Notwithstanding the foregoing, Vendor
agrees that Company shall have the right to approve the initial salary payable
to any Representative hired by Vendor who is an employee of Company as of the
date of this Agreement.

         5.3      Sales, Use and Excise Taxes. If any state or local government
or other taxing authority determines that sales, use or excise Taxes ("Taxes")
are applicable to Vendor's services performed hereunder, Vendor shall promptly
accrue and Company shall pay such Taxes on behalf of Vendor to the appropriate
taxing authorities. In addition, Company shall be responsible for the payment of
any applicable Taxes related to Company's supply to Vendor of Product
Promotional Materials and Product Samples.

         5.4.     No Joint Venture. Nothing contained in this Agreement shall be
construed as creating a joint venture or, except as otherwise provided herein,
as granting to either party the authority to bind or contract any obligations in
the name of or on the account of the other party or to make any guarantees or
warranties on behalf of the other party.

                                   ARTICLE VI
                                    TRAINING

         6.1.     Training Programs.

                  (a)      Company and Vendor shall conduct a training program
(of approximately five (5) days duration) for the Representatives and Managers
prior to the commencement of the Program (but after Company makes pre-stocking
shipments of Products) (the "Training Program"). The Company shall prepare and
conduct its portion of the Training Program on such medical and technical
information about the Products. Vendor shall prepare and conduct its portion of
the Training Program on sales skills, data gathering, regulatory requirements
and applicable laws, recalls, electronic equipment, and Vendor's policies and
procedures. Except as provided in Schedule 3.1, each party shall be responsible
for its own costs in connection with the preparation and conducting its portion
of the Training Program.

                  (b)      In order to qualify for assignment in a Territory, a
Representative must demonstrate thorough knowledge of the Products by passing
Company approved Product tests at a level of proficiency agreed upon by Company
and Vendor.

         6.2.     Training Materials. With the advice and assistance of Company,
Vendor shall prepare written training materials for the Training Program and an
up-to-date programmed learning unit for the Products, to be sent to each
Representative for "at home" study a minimum of five (5) days prior to the
commencement of the Training Program. Company shall provide vendor with clinical
and other information about the Products in order to prepare such written
training materials and programmed learning unit.

                                       12
<PAGE>   13

         6.3.     Company Assistance. During the term of this Agreement Company
shall assist Vendor's Representatives and Managers with respect to the Training
Program and additional orientation and ongoing training for the Representatives.

                                   ARTICLE VII
                                     SAMPLES

         7.1.     Provision of Samples. Company shall provide samples of the
Products to the Representatives at Company's option and at its expense. Company
shall determine the quantity and types of samples to be provided to the
Representatives and the method of distribution of the samples. In the event
Company elects to have Vendor manage the storage and distribution of samples,
Vendor shall pass on to Company the actual invoice costs for storage,
distribution and other related costs and use prudent business sense in costs
incurred. All samples shall be stored and handled by Company and Vendor in
compliance with the PDMA and applicable law.

         7.2      Sample Accountability. Vendor shall prepare and provide to
Company for approval a sample accountability program applicable to the samples
provided by Company.

         7.3.     Return of Samples. Within 30 days following the termination or
expiration of this Agreement or within 30 days from the termination or removal
from the Program of a Representative (unless such Representative has been hired
or retained by Company), Vendor shall cause the Representatives to return to
Company all unused Product samples provided to Vendor or the Representatives by
Company. Company shall pay or reimburse Vendor for all costs and expenses in
connection with the storage and shipment of returned samples.

                                  ARTICLE VIII
                   TRADEMARKS AND INTELLECTUAL PROPERTY RIGHTS

         The Products shall be Detailed by Vendor's Representatives under
trademarks owned by Company or an Affiliate of Company. This Agreement does not
constitute a grant to Vendor of any property right or interest in the Products
or any trademarks which Company or an Affiliate of Company uses with respect to
the Products or to the name or business style of Company. Vendor and the
Representatives shall use the Product Promotional Materials only for the
purposes of this Agreement, and all copyright and other intellectual property
rights in the Product Promotional Materials shall remain with Company.

                                   ARTICLE IX
                     COMMUNICATIONS; MONITORING THE PROGRAM

         9.1.     Communications from Third Parties. Subject to Article XI,
Vendor and its Representatives shall use their best efforts to advise Company of
all comments, statements, requests and inquiries of the medical profession or
any other third parties relating to the Products that are not addressed by
either Product Labeling or the Product Promotional Materials, of which Vendor
becomes aware. All responses to such communications to the medical profession or
such other third parties shall be handled solely by Company. Vendor shall
provide reasonable

                                       13
<PAGE>   14

assistance to Company to the extent requested by Company, and at Company's cost
and expense, to fully respond to such communications.

         9.2.     Government Agencies. Subject to Article XI, all communications
with government agencies, including the FDA, concerning the Products shall be
the sole responsibility of Company. Vendor shall assist Company with respect to
such communications with government agencies to the extent requested by Company,
and at Company's cost and expense. Vendor shall use its best efforts to provide
Company with any documents or information reasonably requested by Company for
purposes of responding to any communications with government agencies within 24
hours of Company's request.

         9.3.     Customer Communications. In addition to Detailing, Vendor
shall assist Company with respect to customer communications (as reasonably
requested by Company and at Company's cost and expense) within the Territory and
shall regularly advise Company of market, economic, regulatory and other
developments of which Vendor may become aware which may affect the sale of the
Products in the Territory.

         9.4.     Appointment of Coordinators. The parties shall each appoint an
authorized coordinator of the Program ("Coordinators") between whom all
communications required or desired to be given will be sent and between whom
Detailing activities will be coordinated. Within 30 days of signing this
Agreement, each party will notify the other as to the name of its Coordinator.
Each party may replace its Coordinator at any time, upon notice to the other
party.

         9.5.     Review of Results. The parties shall confer periodically, but
at least once per month via telephone conference and once per calendar quarter
in person, if requested by either party, to review and discuss the actual
results compared to the marketing plans for Detailing of the Products, and share
data, reports and other documents relative to such results. A report similar to
the Form of Management Report set forth in Schedule 9.5 attached hereto, shall
be generated by Vendor and provided to Company. Vendor shall, upon Company's
request, include the participation of Representatives and/or Managers in such
review.

                                    ARTICLE X
                                    INSURANCE

         10.1.    Vendor Insurance Coverage. Vendor shall maintain insurance
coverage as follows:

                  (a)      Workers' Compensation insurance with statutory limits
of liability and Employer's Liability insurance with a limit of $500,000;

                  (b)      Commercial General Liability insurance, including
completed operations and products liability, with a combined single limit of
$2,500,000;

                  (c)      Automobile liability insurance with a combined single
limit of $1,000,000.

                                       14
<PAGE>   15

         10.2.    Company Insurance Coverage. Company shall maintain Commercial
General Liability insurance with a combined single limit of at least $6,000,000
and Products Liability insurance with a limit of at least $10,000,000.

         10.3     Certificates of Insurance.All of the foregoing insurance shall
be maintained with responsible carriers and such terms of coverage shall be
evidenced by certificates of insurance furnished by one party to the other. Such
certificates of insurance shall provide for at least 30 days' written notice to
the other party prior to cancellation or modification of any of the material
terms of such coverage, and include the other party as an additional insured.

                                   ARTICLE XI
                ADVERSE REACTION REPORTING AND REGULATORY MATTERS

         11.1.    Immediate Notification. Vendor and Company agree to notify the
other party as soon as reasonably practicable of any information that each may
obtain or learn concerning any Product or package complaint or any serious
unexpected side effect, injury, toxicity, or sensitivity reaction or any
unexpected incidence of severity thereof associated with the clinical uses,
studies, investigations, tests and marketing of the Products, whether or not
determined to be attributable to the Products. "Serious" and "unexpected," as
used herein, shall have the meanings set forth in 21 CFR 314.80(a).Each party
shall also notify the other in a timely manner of any other adverse experience,
i.e., any unfavorable and unintended change in the structure (signs), function
(symptoms) or chemistry (laboratory data) of the body temporally associated with
the use of the Products, whether or not considered related thereto.

         11.2.    Threatened Agency Action. Vendor and Company shall each
immediately notify the other party of any information that each may obtain or
learn regarding any threatened or pending action by an Agency which may affect
the Products. Vendor shall, at the request of Company and at the cost and
expense of Company, cooperate with Company in formulating a procedure for taking
appropriate action in response to such information. Unless compelled by law,
Vendor shall not respond to an Agency without the prior written consent of
Company.

         11.3.    Training. Vendor and Company shall develop appropriate
instructions in the Training Program for Representatives as to handling of
information received or obtained subject to Sections 11.1 and 11.2.

                                   ARTICLE XII
                                  RETURN/RECALL

         12.1.    Returned Products.

                  (a)      Company shall be responsible for handling all
returned Products, including shipment and compensation or credit for the
returned Products. Any Products inadvertently returned to Vendor shall be
shipped to Company or at its direction, in compliance with Company's returned
goods policy, and Vendor shall advise the customer who made the return that the
Products have been returned to Company. Company shall reimburse Vendor's
shipping and other costs in connection with the handling of such returned
Products within 30

                                       15
<PAGE>   16

days of delivery to Company of Vendor's statement for such costs. Upon request
Vendor shall provide Company with documentation relating to such costs.

                  (b)      At Company's request, Vendor shall assist Company in
obtaining and receiving any Products that have been recalled, and any costs
incurred by Vendor with respect to participating in any such recall shall be
reimbursed by Company within 30 days of delivery to Company of Vendor's
statement for such costs.

                                  ARTICLE XIII
                            CONFIDENTIAL INFORMATION

         13.1.    Confidential Information. Vendor acknowledges and agrees that
it will have access to, or become acquainted with, Confidential Information of
Company in the course of the performance of services under this Agreement. For
the purposes of this Agreement, "Confidential Information" shall mean any
information of Company or any Affiliate thereof, which gives Company an
advantage over its competitors who do not possess such information and
constitutes valuable trade secrets and/or proprietary data which was revealed to
Vendor as a result of entering into or performing its obligations under this
Agreement, including but not limited to, information which relates to Products,
the Program, Target Customers, designs, methods, discoveries, improvements,
documents, trade secrets, proprietary rights, business affairs, customer
information or employee information. Provided, however, that Confidential
Information shall not include any information that:

                  (a)      Was known to Vendor prior to execution of this
Agreement. without an obligation to keep it confidential;

                  (b)      Was lawfully obtained by Vendor from a third party
without any obligation of confidentiality;

                  (c)      Is, at the time of disclosure, in the public
knowledge;

                  (d)      Becomes part of the public knowledge after disclosure
by publication or otherwise, except by breach of this Agreement;

                  (e)      Is developed by Vendor independently and apart from
this Agreement; or

                  (f)      Is otherwise knowledge possessed by Vendor or its
employees as the result of their industry experience or education.

         13.2     Handling of Confidential Information. Except as otherwise
required by law, Vendor shall keep all Confidential Information in confidence
and shall not, at any time during or for a period of five (5) years from the
termination of this Agreement, without Company's prior written consent, disclose
or otherwise make available, directly or indirectly, any Confidential
Information to anyone other than Vendor employees and Representatives who need
to know the same in the performance of the services hereunder. Vendor shall use
the Confidential Information only in connection with the performance of the
services hereunder and for no other

                                       16
<PAGE>   17

purpose. Vendor shall inform its employees and Representatives of the trade
secret, proprietary and confidential nature of the Confidential Information.

         13.3     Prior Confidentiality Agreements. With respect to all
Confidential Information of Company which has previously been or which may be
disclosed to Vendor under the Confidentiality Agreement dated as of April 15,
2000 between the parties hereto or the letter agreement dated April 28, 2000
between Company and Cardinal Health (including the parties encompassed by said
term by footnote) (together, the "Prior Confidentiality Agreements") or this
Agreement, Company shall have the cumulative benefit of Vendor's confidentiality
covenants under the Prior Confidentiality Agreements and this Agreement, and
neither of the Prior Confidentiality Agreements nor this Agreement shall be
deemed to supersede or control over the other such agreements to the
disadvantage of Company with respect to its Confidential Information.

                                   ARTICLE XIV
                              TERM AND TERMINATION

         14.1.    Term. This Agreement shall take effect on the date on which
both parties execute this Agreement (the "Effective Date"), but the Program
shall continue in effect until the date thirty-six (36) months after the Product
Launch Date (the "Initial Term"), unless terminated earlier as set forth herein.
Notwithstanding the foregoing, Company may, at its option upon written notice to
Vendor at least 120 days prior to the expiration of the Initial Term, and with
the written consent of Vendor, extend the Initial Term for one additional year
(the "Renewal Term"). If Company desires to exercise renewal term, parties shall
negotiate in good faith provisions of Section 3.1(b) regarding compensation.
References in this Agreement to the term of this Agreement include both the
Initial Term and the Renewal Term, if applicable.

         14.2.    Bankruptcy: Insolvency. Either party may terminate this
Agreement upon notice to the other upon the occurrence of: (a) the entry of a
decree or order for relief by a court of proper jurisdiction in an involuntary
case of the other party under the Federal Bankruptcy Code, as now constituted or
hereafter amended, or any other applicable federal or state insolvency or other
similar laws, and the continuance of any such decree or order in effect for a
period of sixty (60) consecutive days; or (b) the filing by the other party of a
petition for relief under the Federal Bankruptcy Code, as now constituted or
hereafter amended, or any other applicable federal or state insolvency or
similar laws.

         14.3     Termination For Breach. Either party may terminate this
Agreement upon 30 days prior written notice if the other party breaches a
material provision of this Agreement and fails to cure the breach within 15 days
after written notice from the non-breaching party. Provided, however, that such
cure period shall be five (5) days in the case of material breach under Section
3.5.

         14.4     Termination Due To Delay in Product Launch. If the Product
Launch Date does not occur within 120 days after the Effective Date, either
party may terminate this Agreement upon 60 days written notice to the other.

                                       17
<PAGE>   18

         14.5     Termination Due To Regulatory And Other Problems. If the
Product is not being marketed due to regulatory problems, court or
administrative proceedings, product liability claims, recalls, raw materials
shortages, or similar factors beyond the control of Company, then either party
may terminate this Agreement upon 30 days written notice to the other. If the
Agreement is not terminated pursuant to this Section 14.5, (a) the provisions of
Sections 2.3, 2.4, 2.5, 2.6 and 2.7 shall be of no force or effect until the
Company recommences the marketing of the Product; and (b) Company shall not be
permitted to terminate this Agreement pursuant to Section 14.3 until the Company
recommences the marketing of the Product.

         14.6     Termination Due To Assignment or Change in Control. In the
event of a Change of Control (defined herein), the party that has had a Change
In Control (the "Affected Party") shall give Notice to the other party (the
"Non-Affected Party") within 30 days of the occurrence of such Change In
Control. If the Change In Control involves a material and direct competitor of
the Non-Affected Party, the Non-Affected Party may terminate this Agreement by
written notice to the Affected Party within 60 days after receipt of the Notice
of a Change In Control. If the Change In Control does not involve a material and
direct competitor of the Non-Affected Party, this Agreement may not be
terminated by the Non-Affected Party. For purposes of this Section, "Change In
Control" includes a purchase, assignment or transfer of a controlling interest
in the Affected Party or substantially all of its business and assets and any
merger or consolidation involving the Affected Party or any Affiliate of the
Affected Party that requires a vote of the stockholders of the Ultimate Parent
of the Affected Party. "Ultimate Parent" for Vendor is Cardinal Health, Inc. and
the Ultimate Parent for Company is its stockholders.

         14.7.    Termination Due to Discontinuation of Product. Company may
terminate this Agreement on 30 days' prior written notice if Company elects to
discontinue the promotion, sale or distribution of the Product from the
marketplace. This provision shall not be available if Company simply wants to
change the party or parties or means for Detailing the Product.

         14.8     Termination: Phase Out. In the event that this Agreement is
terminated pursuant to Sections 14.2 through 14.7 and at Company's request, the
parties shall discuss in good faith an appropriate phase-out of Vendor's
Detailing activities.

         14.9.    Termination: Continuing Rights. The termination or expiration
of this Agreement shall not affect Company's obligation to reimburse or pay
Vendor any amount then due and owing under this Agreement. Further, the
termination or expiration of this Agreement shall not affect any rights or
obligations of any party under this Agreement which are intended by the parties
to survive such termination. The Service Fee paid by Company for the month in
which this Agreement is terminated shall be prorated based on the number of days
in that month, and Vendor shall refund any overpayment to Company.

         14.10    Termination: Return of Materials. Within 60 days following the
termination or expiration of this Agreement, Vendor shall return to Company all
Confidential Information, Product Promotional Materials, marketing plans, forms,
territory lists, reports and any and all other tangible items provided to Vendor
by Company.

                                       18
<PAGE>   19

                                   ARTICLE XV
                           RECORDKEEPING; AUDIT RIGHTS

         15.1.    Vendor Record Keeping: Inspection by Company. Vendor shall
keep accurate records in sufficient detail as to: (i) Detailing activities by
Representatives; and (ii) costs and expenses for which Company must reimburse
Vendor under this Agreement. Upon Company's reasonable request made during or
within three (3) year after the term of this Agreement, and at Company's
expense, Vendor shall permit Company's designated employees or agents to have
access during ordinary business hours to records of such matters. Company and
its designated employees or agents shall maintain in confidence all such cost
and expense records of Vendor.

                                   ARTICLE XVI
                                 INDEMNIFICATION

         16.1     Definitions. As used in this Article 16 and this Agreement,
"Damages" shall mean all liabilities, damages, assessments, levies, losses,
fines, penalties, costs, and expenses, including, without limitation, reasonable
attorneys', accountants', investigators', and experts' fees and expenses,
sustained or incurred as a result of any claims, suits, liabilities, or actions
of any nature.

         16. 2.   Indemnification by Vendor. Subject to the extent of any
indemnification from Company pursuant to Section 16.3 hereof, Vendor shall
indemnify and hold Company, its Affiliates, directors, officers, employees and
agents harmless from and against any and all Damages, except to the extent such
damages arise from the negligence or intentional wrongful actions of Company,
arising directly or indirectly from:

                  (a)      Vendor's breach of or failure to comply with any of
its obligations under this Agreement;

                  (b)      any inaccuracy in or breach or failure of any
representation, warranty, or covenant made by Vendor in this Agreement;

                  (c)      any negligent or wrongful act or omission on the part
of Vendor or its employees or agents;

                  (d)      Vendor's violation of or failure to comply with all
applicable laws, including but not limited to the Act, the PDMA, the Medicare
and Medicaid Anti-Kickback Act (42 U.S.C. Section 1320a-7b(a)), the Civil False
Claims Act (31 U.S.C. Section 3729(a)), Sections 1128A, 1128B, and 1877 of the
Social Security Act (42 U.S.C. Sections 1320a-7a, -7b, and 1395nn), the Health
Care Fraud Act (18 U.S.C. Section 1347), and the Criminal False Claims Act (18
U.S.C. Section 287), as amended from time to time, as well as similar applicable
state laws;

                  (e)      Detailing of the Products, except to the extent such
Damages arise from a negligent or wrongful act or omission of Company; or

                                       19
<PAGE>   20

                  (f)      any federal or state claim or assessment for
nonpayment or late payment by Vendor of any tax or contribution based on the
status of any Representatives as employees of Vendor.

         16.3.    Indemnification by Company. Subject to the extent of any
indemnification from Vendor pursuant to Section 16.2 hereof, Company shall
indemnify and hold Vendor and its Affiliates, directors, officers, employees and
agents harmless from and against any and all Damages, except to the extent such
damages arise from the negligence or intentional wrongful actions of Vendor,
arising directly or indirectly from:

                  (a)      Company's breach of or failure to comply with any of
its obligations under this Agreement;

                  (b)      any inaccuracy in or breach or failure of any
representation, warranty, or covenant made by Company in this Agreement;

                  (c)      any negligent or wrongful act or omission on the part
of Company or its employees or agents;

                  (d)      Company's violation of or failure to comply with all
applicable laws, including but not limited to the Act, the PDMA, the Medicare
and Medicaid Anti-Kickback Act (42 U.S.C. Section 1320a-7b(a)), the Civil False
Claims Act (31 U.S.C. Section 3729(a)), Sections 1128A, 1128B, and 1877 of the
Social Security Act (42 U.S.C. Sections 1320a-7a, -7b, and 1395nn), the Health
Care Fraud Act (18 U.S.C. Section 1347), and the Criminal False Claims Act (18
U.S.C. Section 287), as amended from time to time, as well as similar applicable
state laws;

                  (e)      Detailing of the Products, except to the extent such
Damages arise from a negligent or wrongful act or omission of Vendor;

                  (f)      the accuracy or completeness of the Product Labels,
Product Promotional Materials, or the Training Program;

                  (g)      any claims or liabilities for injury to or death of
persons, regardless of when such claim or liability is asserted or incurred,
resulting from or arising out of the manufacture, use, sale of the Products, or
a manufacturing design or defect of the Products, or any failure to warn or
inadequacy of warning regarding the Products;

                  (h)      Company's failure to pay when due or to reimburse
Vendor for any Taxes (as defined in Section 5.3);

                  (i)      any negligent or wrongful acts or omissions on the
part of Company with respect to Vendor's employees or Representatives or those
individuals who have made application to be Representatives of Vendor; or

                                       20
<PAGE>   21

                  (j)      any federal or state claim or assessment for
nonpayment or late payment by Company of any tax or contribution based on the
status of any former Representatives as employees or agents of Company.

         16.4.    Indemnification Procedures. A party that intends to claim
indemnification under this Article 16 "(the "Indemnitee") shall promptly notify
the other party (the "Indemnitor") in writing of any action, claim or liability
in respect of which the Indemnitee or any of its employees or agents are
entitled to indemnification. The Indemnitee shall permit, and shall cause its
employees and agents to permit, the Indemnitor at its discretion, to settle any
such action, claim or liability and agrees to the complete control of such
defense or settlement by the Indemnitor. Provided, however, that such settlement
or defense does not adversely affect the Indemnitee's rights hereunder or impose
any obligations on the Indemnitee in addition to those set forth in this
Agreement. The Indemnitee, its employees, and agents, shall cooperate fully with
the Indemnitor and its legal representatives in the investigation and defense of
any action, claim or liability subject to indemnification. The Indemnitee shall
have the right, but not the obligation, to be represented by counsel of its own
selection and at its own expense in connection with any indemnified claim.

         16.5.    Limitation on Vendor Liability. It is understood that Vendor
is not an insurer and that the sums payable hereunder to Vendor by Company are
based upon the value of services offered and the scope of liability undertaken,
and such sums are not related to any potential liability of Company. Vendor
makes no warranty, expressed or implied, that the services it furnishes will
avert or prevent occurrences or the consequences therefrom which may result in
loss or damage to Company. In the event of any Damages of which Vendor is
liable, Company agrees that Vendor's liability to indemnify Company shall be
limited to the greater of: (i) Two Million Five Hundred Thousand and 00/100
Dollars ($2,500,000.00) or (ii) the total amount paid by Company to Vendor under
this Agreement. Each party hereby waives any and all rights to subrogation that
any insurer of such party may have against the other party. Except as
hereinabove provided, each party agrees that the other party shall not be liable
for any losses or damages, irrespective of origin, to person or property,
whether directly or indirectly caused by performance or non-performance of
obligations imposed by this Agreement or by the negligent acts or omissions of
the other party , its agents, employees or Representatives.

         16.6     No Consequential Damages. Notwithstanding any provision of
this Agreement to the contrary, neither party shall be liable to the other for
any consequential damages (other than liability for personal injury as provided
in this Article 16), including lost profits.

                                  ARTICLE XVII
                                  MISCELLANEOUS

         17.1.    No Waiver: Cumulative Remedies. No failure or delay on the
part of either party in exercising any right, power or remedy hereunder shall
operate as a waiver thereof; nor shall any single or partial exercise of any
such right, power or remedy preclude any other or further exercise thereof or
the exercise of any other right, power or remedy hereunder. No waiver of any
provision hereof shall be effective unless in writing and signed by the party
giving such waiver.

                                       21
<PAGE>   22

The remedies herein provided are cumulative and not exclusive of any remedies
provided by law.

         17.2.    Captions. Article and Section headings used in this Agreement
are for convenience only and shall not affect the construction of this
Agreement.

         17.3.    Governing Law. This Agreement shall be construed and the
respective rights of the parties hereto determined according to the substantive
laws of the State of Ohio, exclusive of conflict of laws principles.

         17.4.    Severability. If any provision of this Agreement or any other
document delivered under this Agreement is prohibited or unenforceable in any
jurisdiction, it shall be ineffective in such jurisdiction only to the extent of
such prohibition or unenforceability, and such prohibition or unenforceability
shall not invalidate the balance of such provision to the extent it is not
prohibited or enforceable nor the remaining provisions hereof, nor render
unenforceable such provision in any other jurisdiction. In the event any
provisions of this Agreement shall be held to be invalid, illegal or
unenforceable, the parties hereto shall use their best efforts to substitute a
valid, legal and enforceable provision which, insofar as practical, implements
the purposes hereof.

         17.5.    Entire Agreement: Modification. This Agreement contains the
entire and exclusive agreement between the parties in respect of the subject
matter hereof and supersedes and cancels all previous agreements, negotiations,
commitments and writings between the parties hereto in respect of the subject
matter hereof. Except as provided herein, this Agreement may not be changed or
modified in any manner or released, discharged, abandoned or otherwise
terminated unless in writing and signed by the duly authorized officers or
representatives of the parties.

         17.6.    Notices. Any notice or request required or desired to be given
in connection with this Agreement shall be deemed to have been sufficiently
given if sent by pre-paid registered or certified mail or national express
courier (such as Federal Express or UPS) or facsimile transmission to the
intended recipient at the address set forth below or such other address as may
have been furnished in writing by the intended recipient to the sender, and
carrier documentation evidencing delivery to the receiving party or facsimile
answerback is obtained. The date of mailing or facsimile transmission of a valid
notice as described above shall be deemed to be the effective date on which
notice was given.

         All notices shall be addressed to:

                  If to Company, to:
                  Guilford Pharmaceuticals, Inc.
                  6611 Tributary Street
                  Baltimore MD 21224
                  Fax: 410-631-6899

                                       22
<PAGE>   23

                  Attention:
                  General Counsel and
                  Chief Financial Officer

                  to Vendor, to:
                  Cardinal Health Sales and Marketing Services,
                  a division of RedKey, Inc.
                  7000 Cardinal Place
                  Dublin, Ohio 43017
                  Fax: (614) 757-6000

                  Attention:
                  President

         17.7.    Execution in Counterparts. This Agreement may be executed in
counterparts, each of which, when executed and delivered, shall be deemed to be
an original and all of which together shall constitute one and the same
document.

         17.8.    Assignment. This Agreement may not be assigned or transferred
by a party without the prior written consent of the other party hereto.

         17.9.    Public Announcements. Any public announcement, press release
or similar publicity with respect to this Agreement or the transaction
contemplated hereby shall be at such time and in such manner as the parties
shall mutually agree, provided that nothing herein shall prevent either party
from making such public announcements as it deems necessary in order to comply
with applicable laws and regulations, including disclosure requirements of
federal securities laws and requirements of federal food and drug laws.

         17.10.   Maintenance of Records. Vendor and Company each agree that
throughout the term of this Agreement and for a period of six years after the
termination of this Agreement, each will maintain records and otherwise
establish procedures to assure compliance with all regulatory, professional, and
other applicable legal requirements which relate to the Detailing and marketing
of the Products and if applicable, with the other services and activities to be
performed hereunder.

         17.11.   Force Majeure. Failure of either party hereto to fulfill or
perform its obligations under this Agreement shall not subject such party to any
liability if such failure is caused or occasioned by, without limitation, acts
of God, acts of the public enemy, fire, explosion, flood, drought, war, riot,
sabotage, embargo, strikes or other labor disputes (which strikes or disputes
need not be settled), compliance with any order, regulation, or request of
government, or by any other event or circumstance of like or different character
to the foregoing beyond the reasonable control and without the fault or
negligence of such party (a "Force Majeure Event") provided such party uses
reasonable efforts to remove such Force Majeure Event and gives the other party
prompt notice of the existence of such Force Majeure Event. Provided, further,
that

                                       23
<PAGE>   24

no Force Majeure Event shall serve to delay or excuse any payment by one party
to the other then due and owing.

         IN WITNESS WHEREOF, the parties have caused this Agreement to be
executed by their duly authorized officers.

CARDINAL HEALTH SALES                       GUILFORD PHARMACEUTICALS INC.
AND MARKETING SERVICES,
a division of RedKey, Inc.

By /s/ Don Wetherhold                       By /s/ John P. Brennan
   --------------------------                  ----------------------------

Name:  Don Wetherhold                       Name:  John P. Brennan
       ----------------------                      ------------------------

Title: President                            Title: Sr. Vice President
       ----------------------                      ------------------------

Date:  October 24, 2000                     Date:  October 25, 2000
       ----------------------                      ------------------------

                                       24

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