Document:

<PAGE>
                                                                 Exhibit 10.15.1

          Confidential Materials omitted and filed separately with the
              Securities and Exchange Commission. Asterisks denote
                                   omissions.

                    SECOND AMENDMENT TO COOPERATIVE AGREEMENT

         This SECOND AMENDMENT TO COOPERATIVE AGREEMENT is made and entered into
as of this 11th day of April, 2002, by and among Novirio SARL, a private
corporation located at Immeuble "La Vigie," 170 Rue Leon Blum, 34000 Montpellier
("Novirio"), Le Centre National de la Recherche Scientifique, located at 3 Rue
Michel-Ange 75794, Paris, Cedex 16 ("CNRS"), and L'Universite' Montpellier II,
located at 2 Place Eugene Bataillon 34095, Monpellier ("UMII") (together, the
"Parties").

         Whereas, Novirio, CNRS and UMII are parties to a certain Cooperative
Agreement dated as of January 4, 1999 ("the Cooperative Agreement"), pursuant to
which, inter alia, the parties have established a Cooperative Laboratory; and

         Whereas, Novirio, CNRS and UMII entered into a First Amendment
Agreement dated as of May 17, 2001 to amend and clarify certain terms of the
Cooperative Agreement; and

         Whereas, the parties now desire to further amend and clarify the
Cooperative Agreement as amended on May 17, 2001;

         NOW THEREFORE, for and in consideration of the foregoing, the mutual
covenants herein contained and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereby
agree as follows.

         1.       The reference to NOVIRIO Limited, in the first paragraph of
the Cooperative Agreement is understood and amended to refer to NOVIRIO
PHARMACEUTICALS Limited.

         2.        Article 9.1 is amended to read as follows.

         Results obtained by the COOPERATIVE LABORATORY, within the framework of
research carried out under this Agreement, are owned jointly by the Parties.
Results ("Results") include, but are not limited to, technical information,
laboratory notebooks, data, trade secrets, know how, proprietary information and
inventions, documents and materials arising out of such research.

         The parties further agree that any and all rights, title and interest
in the technology, inventions, and/or discoveries directly or indirectly
relating to the subject matter of the patent applications U.S. application
numbers [**] and all continuations, divisionals, continuations-in-part, foreign
counterparts, and all other U.S. and international patent filings that claim
priority to these applications or to which these applications claim priority are
deemed to be included in the results obtained by the COOPERATIVE LABORATORY
regardless of whether the work was carried out prior to the formation of the
COOPERATIVE LABORATORY and regardless of the

<PAGE>

person or institution that carried out the work. Such work specifically includes
compositions, use and manufacture of [**], and analogs thereof for the treatment
of [**], including humans.

         The rules of co-ownership are defined in Annex 3 and are an integral
part of this Agreement.

         3.       Article 9.2 is amended by adding the following paragraph as
the last paragraph of the Article.

         The parties agree that Results obtained outside of the Cooperative
Laboratory as defined in this Section do not include any and all rights, title
and interest in the technology, inventions, and/or discoveries directly or
indirectly relating to the subject matter of the patent applications U.S.
application numbers [**] and all continuations, divisionals,
continuations-in-part, foreign counterparts, and all other U.S. and
international patent filings that claim priority to these applications or to
which these applications claim priority, which, by agreement of Novirio and the
Organization, are specifically deemed to fall under Article 9.1 as Results of
the Cooperative Laboratory. The parties further agree that compositions, use and
manufacture of [**], and analogs thereof for the treatment of [**], including
humans fall under Article 9.1 and not Article 9.2.

         4.       Article 10.2.1a) is amended by replacing the existing
paragraph with the following paragraph.

         Novirio has the exclusive world-wide right to exploit, directly or
indirectly, the Results obtained in the Exploitation Field within the framework
of the Cooperative Laboratory, which includes, without limitation, the right to
make, have made, use, sell, offer for sale and import the Results of the
Cooperative Laboratory in the Exploitation Field, either directly or indirectly,
for all commercial purposes, and the right to enter into license agreements and
collaborations on its own or through its affiliates with third Parties to
authorize such third parties to make, use, sell, offer for sale and import said
Results for all commercial purposes, and Novirio agrees to provide a royalty to
the Organization under the conditions prescribed in Article 11.

         5.       Article 10.2.1c) is amended by replacing the existing
paragraph with the following paragraph.

         In the event of indirect exploitation by Novirio, Novirio is granted
have the unlimited right to act behalf of the Parties, and to sign all
agreements with any and all third parties in Novirio's sole discretion and
without the Organization's prior permission. Indirect exploitation shall include
a collaboration, nonexclusive or exclusive license agreement, option agreement,
or other relationship or agreement with another institution that passes any
right or partial right granted to Novirio under Article 10.2.1a) to that
institution. Novirio will advise the Organization of any such indirect
exploitation and will transmit a copy of the signed agreements to the
Organization.

<PAGE>
         6.       Article 12 is amended by adding the following paragraph.

In Article 12, the first clause of the first sentence of the last paragraph is
amended to read:

Notwithstanding the expiration or termination of the Agreement or its
anticipated cancellation:

         7.       Article 13 is amended by replacing the existing paragraph with
the following paragraph.

         The Parties agree that this contract will be construed and interpreted
under French law. The parties shall try to settle out of court litigation and
disputes that could arise from the interpretation of this Agreement. In the case
of persistent disagreement, any disputes among the parties will be heard in a
court of competent jurisdiction.

         8.       Annex 3, entitled "Co-ownership Settlement of Cooperative
Laboratory Results" is amended as follows.

The first paragraph is replaced with the following sentence.

         Any patent applications covering the Results obtained in the framework
of the COOPERATIVE LABORATORY will be filed in the names of the appropriate
parties under the law of the country of the patent filing, but will be exploited
according to the terms of this contract for the benefit of all of the Parties.
Novirio will [**] for submitting a patent, for the patent being granted, for
maintaining the patent, and for defending it.

         9.       Article 4.3 of Annex 3 is replaced with the following
paragraph.

         The parties hereby grant Novirio the first, full and sole right to
enforce or defend any patent obtained covering Results at Novirio's sole
expense, and the Organization agrees to cooperate, assist, and participate in
any litigation that Novirio deems necessary or desirable to defend such patents.
If Novirio elects in writing not to defend or enforce a patent being infringed,
then the Organization is granted the second, full and sole right to enforce or
defend any patent obtained covering Results at the Organization's sole expense,
and then Novirio agrees to cooperate, assist, and participate in any litigation
that the Organization deems necessary or desirable to defend such patents.

         10.      The first two sentences of Article 4.4 are deleted. In the
third sentence of Article 4.4, the word "them" is replaced with "the Parties."

         11.      Article 4.5 of Annex 3 is replaced with the following
paragraph.

         If the Organization does not want to exercise the second right to
enforce the patent, either CNRS or UMII may individually take legal action at
its own expense, wherein Novirio and the

<PAGE>

other party agree to cooperate, assist and participate in any such litigation.
In this case, all damages will be awarded to the litigating party in full.

         12.      Article 5 of Annex 3 is amended by adding the following
sentence to the end of the second paragraph.

         The right of notice and preemption prior to an assignment of patent or
technical rights does not apply in the case of the sale of all or substantially
all of the assets of the party, in which case the co-ownership right flows
automatically with the asset sale to the new owner of the assets. The new owner
of all or substantially all of the assets of the prior co-owner must confirm in
writing its agreement to the co-ownership provisions set forth in this
Agreement.

         13.      CNRS warrants and represents that it is the sole owner of all
inventions, conceptions, trade secrets, technical developments and patents of
Dr. Gilles Gosselin carried out or accomplished in the course of Dr. Gosselin's
research and Results in the Cooperative Laboratory. CNRS has not granted any
rights held by the Cooperative Laboratory to any other entity, and no government
entity or other entity holds such rights other than CNRS.

         14.      UMII warrants and represents that it is the sole owner of all
inventions, conceptions, trade secrets, technical developments and patents of
Dr. Jean-Louis Imbach carried out or accomplished in the course of Dr. Imbach's
research and Results in the Cooperative Laboratory. UMII has not granted any
rights held by the Cooperative Laboratory to any other entity, and no government
entity holds such rights other than UMII.

         15.      All other provisions of the Cooperative Agreement as amended
on May 17, 2001 remain unchanged.

         16.      This Amendment has been drafted in the English language and in
the French language. In case of contradiction between the two versions, the
French version shall prevail.

For the Director General of the CNRS and on his authority, the Regional Delegate

/s/  DANIELLE GRANGE                                       /d/ 4/11/2002
------------------------------------------------------     ---------------------
Name                                                       Date

For the President of the University of Montpellier II

/s/  ALAIN SZAFARCZYK                                      /d/ 4/11/2002
------------------------------------------------------     ---------------------
Name                                                       Date

Chairman and CEO of Novirio

/s/  JEAN-PIERRE SOMMADOSSI                                /d/ 4/11/2002
------------------------------------------------------     ---------------------
Name                                                       Date<PAGE>
                                                                   Exhibit 10.17

          Confidential Materials omitted and filed separately with the
        Securities and Exchange Commission. Asterisks denote omissions.

                                  CO-OPERATIVE

                      ANTIVIRAL RESEARCH ACTIVITY AGREEMENT

THIS AGREEMENT IS MADE BETWEEN:

-     NOVIRIO SARL, a French pharmaceutical company located 23 - 25 rue de
      Berri, 75008 Paris France, on behalf and for the benefit of NOVIRIO
      Pharmaceuticals Limited, a company organized in the Cayman Islands, and
      represented by Bruno Lucidi, President and CEO.

-     The Dipartimento di Biologia Sperimentale "Bernardo Loddo" dell'Universita
      di Cagliari, located Cittadella Universitaria, SS 554 KM 4.5, 09133
      Monserrato, Cagliari, represented by Prof. Giovanni Biggio, Director.

                                      -1-
<PAGE>

1.       PURPOSE

The purpose of this agreement is to define the terms of the co-operative
activity to be undertaken by or for the benefit of each of the parties hereto
and Novirio Pharmaceuticals Limited in connection with research in the field of
antiviral substances, hereafter referred to as `Co-operative activity.' This
agreement covers two entities and in no way creates a corporate, joint venture
or partnership structure or arrangement. It excludes the `affectio societatis'
and any other direct or indirect association with any corporation whatever its
structure may be. Specifically with regard to third parties, each of the parties
will act in its own name and on its own account and will have no authority to
bind the other party hereto.

2.       SCOPE

This agreement is applicable to research in the field of antiviral substances,
the main field of interest of the Section of Microbiology of Dipartimento di
Biologia Sperimentale dell'Universita di Cagliari, and includes without
limitation all research activities directly or indirectly related to the
development of antiviral substances, tests or analytic procedures relating
thereto and all other research activity made necessary by the main activity
which will constitute a part of the co-operative activity.

The initial research program which will constitute a part of the Co-operative
activity is attached (annex 1). In case of inconsistency between annex 1 and
present agreement, the latter shall prevail.

3.       CO-OPERATIVE ACTIVITIES

3.1      PERSONNEL

The Co-operative activity will be carried out by NOVIRIO SARL personnel with the
support of personnel of the Section of Microbiology of the Dipartimento di
Biologia Sperimentale. Temporary personnel may be hired, when necessary, with
funds provided by NOVIRIO SARL. Any employee assigned to the Co-operative
activity by a party hereto shall remain an employee of such party. Such party
shall be responsible for satisfaction of the obligations it owes to the
employees it has assigned to the Co-operative activity, including civil duties,
such as insurance, social security, taxes, accidents at work and illnesses due
to activity. Each party shall be responsible for its own staff administration
and shall be free to evaluate all needs related to its own staff. Each party is
responsible for acts committed by its staff assigned to the Co-operative
activity. It is understood and agreed that every staff member shall follow the
general rules of discipline and security of the Section of Microbiology of the
Dipartimento di Biologia Sperimentale. Each party shall inform its staff, at the
time of assignment to the Co-operative activity, of necessary measures as
regards to the terms of this agreement.

                                      -2-

<PAGE>

3.2      LOCATION / FACILITIES

The Co-operative activity will take place at and within the facilities of the
Section of Microbiology of the Dipartimento di Biologia Sperimentale. The
NOVIRIO SARL personnel assigned to the Co-operative activity will have access to
main services, such as documentation centre, general public services from the
Universita di Cagliari on the same conditions as the personnel of the
Dipartimento di Biologia Sperimentale, under the responsibility of the Director
of the Co-operative activity.

3.3      MEANS

Each party agrees to provide the resources to the Co-operative activity in
accordance with the plan attached hereto in annex 2.

NOVIRIO SARL will retain sole ownership of the basic means which it has supplied
to or paid for the Co-operative activity and shall have the right to remove such
means from the facilities of the Dipartimento di Biologia Sperimentale at the
termination of this agreement.

4.       PARTNERSHIPS AND OTHER AGREEMENTS

Public laboratories or third party entities may collaborate with the parties
hereto in connection with the Co-operative activity, provided, that such
collaboration is regulated by a written agreement with third parties signed by
NOVIRIO SARL and a representative of the Dipartimento di Biologia Sperimentale
specifying the purpose, the duration and the party's contributions and shall not
affect the rights and obligations of the parties arising in connection with or
pursuant to Articles 8, 9 and 10 of this agreement. The present agreement shall
prevail should inconsistencies occur between agreements.

5.       STEERING COMMITTEE

5.1      ESTABLISHMENT AND MEMBERS

         Pursuant to this agreement, a steering committee is hereby established
         for the purpose of determining the detailed objectives for and research
         programs to be undertaken by the Co-operative activity and for the
         other purposes set forth in Article 5.2 of this agreement. The Steering
         Committee will include at least one representative designated from time
         to time by each party hereto and will consist of not more than 5
         members. The members of the Steering Committee will appoint a chairman.
         The initial members of the Steering Committee are:

              Prof. Jean-Pierre Sommadossi, Chairman of the Board of Novirio
              Pharmaceuticals Limited;
              Mr. Bruno Lucidi, President and CEO of Novirio Pharmaceuticals
              Limited; and
              Prof. Paolo La Colla, Dipartimento di Biologia Sperimentale.

                                      -3-
<PAGE>
         The initial Chairman of the Steering Committee is Prof. Jean-Pierre
         Sommadossi.

5.2      MEETINGS AND RESPONSIBILITIES

The chairman of the Steering Committee shall call a meeting of such committee at
least once a year. Additional meetings of the Steering Committee may be called
by the Chairman as often as the Chairman deems necessary or appropriate. The
Steering Committee shall be responsible for the following matters:

         (i)      the annual determination and establishment of the detailed
                  objectives for and the research programs to be undertaken by
                  the Co-operative activity;
         (ii)     appointment of a Co-operative activity Director and the
                  Steering Committee Chairman;
         (iii)    approval, prior to implementation, of any material
                  modifications proposed by the Co-operative activity director
                  to previously established detailed objectives or research
                  programs;
         (iv)     oversight, monitoring and modification of the operations of
                  the Co-operative activity and the budget attached hereto as
                  annex 2, which oversight shall include but not be limited to
                  decisions regarding staffing, publications and communications
                  in accordance with Article 8 of this agreement and licensing
                  in accordance with Article 10 of this agreement.

5.3      CO-OPERATIVE ACTIVITY DIRECTOR

Subject to the authority vested in the Steering Committee, the operations of the
Co-operative activity will be managed by the Co-operative Director who will be a
member of Dipartimento di Biologia Sperimentale. In addition to general
management of the Co-operative activity and implementation of the decisions of
the Steering Committee, the Co-operative activity Director will prepare and
deliver to the Steering Committee research program proposals and co-operative
activity objectives and proposals for modification of any previously approved
detailed objectives and research programs. The initial Co-operative Activity
Director is Prof. Paolo La Colla.

6.     CONFIDENTIALITY

Each party agrees to keep confidential and not disclose or use, except for
purposes permitted for performance under the agreement, any information
whatsoever including without limitation proprietary or confidential business,
technical or scientific information owned by or related to either one of the
involved parties which has been obtained from or derived from information
provided by the other party in connection with the negotiation and execution of
this agreement or the Co-operative activity. Each party agrees to inform its
staff of the terms of this article and ensure that said staff respect these
terms.

This clause shall remain active for as long as the information is not of public
domain without violation of any duties whatsoever resulting from this article.
The information

                                      -4-
<PAGE>
subject to the obligation of confidential non-disclosure and non-use set forth
above does not include information which has been disclosed with a specific
authorization from the Steering Committee.

If one of the parties should find it necessary for the success of its mission to
disclose confidential information to a third party, this information may only be
disclosed after a prior written authorization from the Steering Committee
specifying the conditions of the disclosure.

7.       PUBLICATIONS AND COMMUNICATIONS

Publications and communications related to the Co-operative activity or the
results therefrom shall occur only after prior authorization from the Steering
Committee and shall specify each party's contribution unless one of the parties
specifically requests not to be mentioned.

To this end, the Director of the Co-operative activity shall request, in a
writing directed to the Steering Committee, authorization for publication. The
Steering Committee shall respond to such request within a maximum 2 months after
the date of receipt of such request. Absence of response within this time limit
shall be considered implied consent.

The Steering Committee shall have the right to review any disclosure prior to
its publication or communication and such publication or communication projects
may be modified or certain information suppressed by the Steering Committee if
the Steering Committee believes disclosure of such information might limit the
availability of patent protection or otherwise harm the industrial and/or
commercial operations that may result from the Co-operative activity.
Nevertheless, the Steering Committee may not refuse communication or publication
after 18 months of request unless the strategic importance of the information to
be disclosed can be reasonably proven. In this specific case, decisions related
to the nature and duration of confidentiality shall be made by the Steering
Committee and the researchers involved in the Co-operative activity who are
required to submit scientific reports, can inform the Dipartimento di Biologia
Sperimentale of the results in a confidential report.

8.       INTELLECTUAL PROPERTY - OWNERSHIP AND PROTECTION

8.1      RESULTS OBTAINED OUTSIDE OF THE CO-OPERATIVE ACTIVITY

Each party retains exclusive ownership of its intellectual property utilized in
and the results of the research and development activities it has carried out
before the date of this agreement. Each party will also retain exclusive
ownership of intellectual property it develops or acquires and results of
research and development activities it has undertaken outside of the
Co-operative activity.

Each party may gratuitously contribute the use of its intellectual property and
knowledge for the realization of work carried out within the scope of the
Co-operative activity.

                                      -5-
<PAGE>
8.2      RESULTS OBTAINED WITHIN THE CO-OPERATIVE ACTIVITY

Results obtained from the Co-operative activity remain the property of both
parties.

Should any party wish to protect results obtained within the Co-operative
activity, it must advise, in writing, the other party, which must inform whether
it wants to protect said results. Absence of response [**] after the date of
receipt of such notice is understood as refusal to participate in protection of
results, in which case the remaining party may deposit results for protection.

Notwithstanding anything to the contrary, Dipartimento di Biologia agrees and
does hereby grant to NOVIRIO Pharmaceuticals Limited the right of first patent
filing on results susceptible to patenting in its own and the Dipartimento di
Biologia Sperimentale name and at NOVIRIO Pharmaceuticals Limited own expenses,
allowing further investment needed to perform full development within the most
appropriate time frame and substantial additional investment necessary for
product to seek for approval with health registration.

In the event NOVIRIO Pharmaceuticals Limited elects not to: (i) file a first
patent and corresponding patents; (ii) continue procedures in view of obtaining
said patents; or (iii) maintain said patents in effect, NOVIRIO SARL agrees to
inform the Dipartimento di Biologia Sperimentale, as soon as practicable after
such election and in a time period reasonably believed to be sufficient, to
allow the latter to accomplish all necessary formalities for the filing and
maintaining, as the case may be, of patents in its own name, if it wishes to do
so.

Each party agrees to cause:

(i)      all patents to mention the name of the inventor (unless requested
         otherwise) in accordance with current legal dispositions regarding
         deposit of patents; and
(ii)     its staff, mentioned as inventors, to sign and accomplish all necessary
         formalities for the deposit, the maintaining and the defense of said
         patents.

Each party also agrees to cooperate with the other in connection with the
deposit and extensions of patents.

9.       INDUSTRIAL OPERATIONS - LICENSING

9.1      INDUSTRIAL OPERATIONS OF RESULTS OBTAINED WITHIN THE CO-OPERATIVE
         ACTIVITY

Dipartimento di Biologia Sperimentale hereby grants to NOVIRIO Pharmaceuticals
Limited the exclusive right to directly or indirectly use or license the results
obtained within or from the Co-operative activity. In case of rewarded
commercial use of such results, NOVIRIO SARL or NOVIRIO Pharmaceuticals Limited
shall pay to the Dipartimento di Biologia Sperimentale a fee as set forth below.
It is understood and agreed by the parties hereto that the assessment and
percentage of the fee have been

                                      -6-
<PAGE>
defined at a reasonable level with reference to similar processes/products
available on the market, and that such assessments and fees have taken into
account the intellectual and financial contributions of the parties with respect
to the invention, the development, the launch and protection of
processes/products. The fees payable by NOVIRIO SARL or NOVIRIO Pharmaceuticals
Limited to the Dipartimento di Biologia Sperimentale, and costs to be incurred
by NOVIRIO SARL or NOVIRIO Pharmaceuticals Limited in the case of rewarded
commercial use of results obtained within or from the Co-operative activity
which have been licensed to Novirio Pharmaceuticals Limited, are as follows:

-        the percentage will be [**]% of the world-wide net sales results;
-        terms of payment will be defined by an agreement signed by the parties
         before commercialization;

-        NOVIRIO SARL or NOVIRIO Pharmaceuticals Limited will incur all costs of
         development and if NOVIRIO Pharmaceuticals Limited licenses out the
         compound, it agrees to use reasonable efforts to cause the Dipartimento
         di Biologia Sperimentale to earn a percentage of the royalties it
         receives or a percentage of sub-licensing fees equivalent to the [**]%
         of the world-wide net sales.

If NOVIRIO Pharmaceuticals Limited elects not to further develop these results,
it could decide to allow the Dipartimento di Biologia Sperimentale to negotiate
with third parties non-exclusive licenses, for patent use or know-how obtained
within the Co-operative activity. In this case, the Dipartimento di Biologia
Sperimentale shall pay NOVIRIO Pharmaceuticals Limited a fee equivalent to [**]%
of world-wide net sales, in accordance with an agreement that will be signed by
the parties before commercialization.

9.2      INDUSTRIAL OPERATIONS OF RESULTS OBTAINED OUTSIDE THE CO-OPERATIVE
         ACTIVITY

9.2.1    RIGHT OF FIRST REFUSAL

Dipartimento di Biologia Sperimentale agrees, subject to confidentiality
obligations rightfully owed by it to third parties pursuant to enforceable
agreements, to provide written notification to either NOVIRIO Pharmaceuticals
Limited or NOVIRIO SARL of any developments and discoveries in the field of
antivirals of which Dipartimento di Biologia Sperimentale becomes aware as soon
as practicable after Dipartimento di Biologia Sperimentale acquires such
awareness.
Dipartimento di Biologia Sperimentale further agrees not to notify any other
third party of such developments or discoveries prior to notifying either
NOVIRIO Pharmaceuticals Limited or NOVIRIO SARL and thereafter for a minimum
period of [**] after delivery of notice to either NOVIRIO Pharmaceuticals
Limited or NOVIRIO SARL. In addition, subject only to the legally enforceable
rights of each of Ministero dell' Universita e della Ricerca Scientifica e
Tecnologica, Intitute Superiore di Sanita, and Regione Autonoma Sardegna,
Dipartimento di Biologia Sperimentale agrees not to enter into any agreements or
arrangements with any third party relating to the license, acquisition,
commercialization or other use of any results or discoveries in the field of
antivirals in

                                      -7-
<PAGE>
which Dipartimento di Biologia Sperimentale acquires or may acquire an interest
prior to offering the same to NOVIRIO Pharmaceuticals Limited. NOVIRIO
Pharmaceuticals Limited shall have a period of [**] after receipt of such notice
to evaluate the results or discoveries and Dipartimento di Biologia Sperimentale
shall, at NOVIRIO Pharmaceuticals Limited expense, cooperate with such
evaluation to the extent reasonably practicable. If, prior to the expiration of
such [**] period, either NOVIRIO Pharmaceuticals Limited or NOVIRIO SARL
notifies Dipartimento di Biologia Sperimentale of NOVIRIO Pharmaceuticals
Limited desire to license, acquire, commercialize or otherwise use such results
or discoveries, Dipartimento di Biologia Sperimentale agrees to execute such
agreements as may be necessary to permit NOVIRIO Pharmaceuticals Limited or its
assigns to license, acquire, commercialize or otherwise use such results or
discoveries on an exclusive basis. The obligation of Dipartimento di Biologia
Sperimentale to execute and deliver such agreements is conditioned upon the
right of Dipartimento di Biologia Sperimentale to receive a fee not lower than
the fee set forth in Article 9.1 in the case of paid commercial use of the
results or discoveries licensed, acquired, commercialized or otherwise used by
NOVIRIO Pharmaceuticals Limited pursuant to this Article 9.2.1. If NOVIRIO
Pharmaceuticals Limited does not notify Dipartimento di Biologia Sperimentale of
its desire to license, acquire, commercialize or otherwise use such results or
discoveries within [**] after receipt of the offer from Dipartimento di Biologia
Sperimentale, Dipartimento di Biologia Sperimentale shall have the right to
offer to other parties the non-exclusive right to license, acquire,
commercialize or otherwise use such results or discoveries.

9.2.2    REVOCATION OF RIGHTS

If, on the second anniversary of an agreement executed by or for the benefit of
NOVIRIO Pharmaceuticals Limited pursuant to Article 9.2.1, NOVIRIO
Pharmaceuticals Limited has not either developed or actively engaged in efforts
to cause the development of any rights or discoveries licensed, assigned or
otherwise acquired by NOVIRIO Pharmaceuticals Limited pursuant to Article 9.2.1,
Dipartimento di Biologia Sperimentale shall have the right to offer to third
parties a non-exclusive interest in such rights and discoveries. NOVIRIO
Pharmaceuticals Limited shall have no right to receive any fees or payments from
either Dipartimento di Biologia or such third parties if such third party
arrangements result in rewarded commercial use.

10.      LITIGATION AND DISPUTES

Parties shall try to settle out of court all litigation and disputes deriving
from the interpretation of this agreement. In case of persistent disagreement
settlement shall fall within the sole competence of the Paris (France) Court.

                                      -8-

<PAGE>

11.    DURATION - TERMINATION

This agreement shall be for the duration of 4 years from date of signature and
will be renewed for this same period by consent expressed in writing by the
parties at least 30 days prior to the expiration of the initial term. Each party
is entitled to terminate this agreement in case of non-respect of one or more
obligations mentioned in this agreement by the other party. Termination shall be
effective 3 months after reception of a registered letter sent by the aggrieved
party specifying the reasons for complaint, unless the defaulting party has
contracted its obligations or proven the fault was a case of `force majeure'
within this time frame.
The possibility of termination shall not exempt the defaulting party from
fulfilling its contracted obligations under this agreement prior to the
effective time of termination. In addition to any other damages suffered by the
non-defaulting party, the defaulting party shall be liable for any harm suffered
by the non-defaulting party due to the early termination of this agreement.

ANNEX 1:
Initial Research Program

ANNEX 2:
Resources and Budget

SIGNATURES:

Dipartimento Di Biologia Sperimentale

By: /s/ Giovanni Biggio
    ----------------------------------
Prof. Giovanni Biggio, Director

NOVIRIO SARL

By: /s/ Bruno Lucidi
    -----------------------------------
Bruno Lucidi, President and CEO

                                      -9-
<PAGE>
                                     ANNEX 1

                                RESEARCH PROGRAM

SCREENING OF CANDIDATE ENTITIES FOR ANTIVIRAL ACTIVITY [**].
       In the past years, the division of microbiology in the department of
       experimental biology has established several research collaborations
       which have resulted in a portfolio of 3,500 chemically synthesized
       compounds and a certain number of natural products. The division of
       microbiology will screen part of this pipeline for possible activity
       [**]. In addition, screening of compounds submitted directly by Novirio
       Pharmaceuticals will also be tested in the facility.
RATIONAL DRUG DISCOVERY [**].
       This research will entail structure activity relationship of selected
       compounds and molecular modelization of the complex 'enzyme-inhibitor' in
       order to rationalize drug synthesis. Pre-clinical studies of compounds
       will be performed [**]. The classes of possible chemical entities to be
       developed include:

                                   [**]

                                      -10-
<PAGE>
                                    ANNEX 2

                                     BUDGET

For the implementation of the Co-operative activity, NOVIRIO SARL commits to
allocate the financial resources detailed in the Table, while the Dipartimento
di Biologia Sperimentale agrees to provide the structures and the basic
equipment necessary for the research activities described in annex 1.
Expenses [**] concerning the [**], will be covered by NOVIRIO SARL directly.
As for the screening activity and the research & development activity, every
year NOVIRIO SARL will pay the Dipartimento de Biologia Sperimentale the sums
shown in the Table, pending continuation of the research program as defined in
the agreement. The use of these proceeds will be regulated by the administrative
rules of the University of Cagliari. The annual budget will be divided into [**]
payments at the beginning of each [**]. The surplus of each term can be used in
the next term. The related statements of an account will be submitted to NOVIRIO
SARL at the end of each term, within and not later than [**] after the end of
the term.
Expenses for the acquisition of the following goods are allowed:

  - Equipment costing not more than [**] Lira altogether; Maintenance of
    equipment;
  - Consumer goods;
  - [**] to be reimbursed by NOVIRIO SARL upon receipt of original invoice;
  - Publication of papers in scientific journals and acquisition of reprints
    which are associated to the study or NOVIRIO;
  - Fees given to temporary personnel (external consultants)

<PAGE>
                                     Annex 2

<TABLE>
<CAPTION>
                      BUDGET FROM DECEMBER 1998 UNTIL 2002 - COOPERATIVE LABORATORY - CAGLIARI (ITALY)
                      --------------------------------------------------------------------------------

---------------------------------------------------------------------------------------------------------------------------------
          (IT LIRA)                [**]           [**]           [**]             [**]               [**]              TOTAL
---------------------------------------------------------------------------------------------------------------------------------
<S>                                <C>            <C>            <C>             <C>                 <C>              <C>
Cost of personnel (loaded)              [**]           [**]           [**]               [**]               [**]             [**]
---------------------------------------------------------------------------------------------------------------------------------
Research scientist senior               [**]           [**]           [**]               [**]               [**]             [**]
---------------------------------------------------------------------------------------------------------------------------------
General expenses                                       [**]           [**]               [**]               [**]             [**]
---------------------------------------------------------------------------------------------------------------------------------
Research & Dvpt costs                                  [**]           [**]               [**]               [**]             [**]
---------------------------------------------------------------------------------------------------------------------------------
Screening costs                                        [**]           [**]               [**]               [**]             [**]
---------------------------------------------------------------------------------------------------------------------------------
Total                                   [**]           [**]           [**]               [**]               [**]             [**]
---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

Cost [**] will be handled directly by Novirio.
Other Costs should be wired by quarter in advance and consolidated yearly, last
quarter. Payments will be made in advance quarterly and expenses monitored and
reported to Novirio on a regular basis quarterly.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00039-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00039-of-00352.parquet"}]]