**Exhibit 10.32**

**Execution Copy**

*****Text Omitted and Filed Separately**

**with the Securities and Exchange Commission.**

**Confidential Treatment Requested**

**Under 17 C.F.R. Sections 200.80(b)(4)**

**and240.24b-2.**

**EXCLUSIVE LICENSE AND RESEARCH COLLABORATION AGREEMENT**

**between**

**IDENIX PHARMACEUTICALS, INC.**

**and**

**METABASIS THERAPEUTICS, INC.**

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EXCLUSIVELICENSE AND RESEARCH COLLABORATION AGREEMENT

**THIS EXCLUSIVE LICENSE ANDRESEARCH COLLABORATION AGREEMENT**  (the***“Agreement”***)is entered into as of October 24, 2006 (the ***“Effective Date”***) by and between **IDENIX PHARMACEUTICALS, INC.**,a Delaware corporation (***“Idenix”***),having an address of 60 Hampshire Street, Cambridge, Massachusetts 02139,and **METABASISTHERAPEUTICS, INC.**, aDelaware corporation (***“Metabasis”***),having an address of 11119 North Torrey Pines Road, La Jolla, California92037.  In this Agreement, Idenix andMetabasis are each referred to individually as a ***“Party”***and collectively as the***“Parties.”***

**RECITALS**

**WHEREAS**, Metabasis has developed MetabasisTechnology (as hereinafter defined) for the discovery and optimization of livertargeted compounds and Idenix owns Idenix Nucleosides (as hereinafter defined);

**WHEREAS**, Idenix and Metabasis desire to enter into abusiness relationship to identify and develop the Collaboration Compounds (ashereinafter defined) and sell Products upon the terms and conditions set forthherein; and

**WHEREAS**, Idenix desires to obtain licenses underMetabasis Technology and Metabasis’ interest in Collaboration Technology andJoint Technology (as each such term is hereinafter defined) to develop andcommercialize Products in the Field (as hereinafter defined), and Metabasisdesires to grant such licenses, in each case upon the terms and conditions setforth herein.

**AGREEMENT**

**NOW, THEREFORE****,**in consideration of the foregoing premisesand the mutual covenants herein contained, the Parties hereby agree as follows:

**1.****                                     ****DEFINITIONS**

Unless specifically set forth to the contraryherein, the following terms, whether used in the singular or plural, shall havethe respective meanings set forth below. References to “Articles”, “Sections”and “subsections” in this Agreement shall be to Articles, Sections andsubsections respectively, of this Agreement unless otherwise specificallyprovided:

**1.1         **[***] shall have the meaning provided inSection 12.6(a).

**1.2         ****“Affiliate”**shall mean any company or entitycontrolled by, controlling, or under common control with a Party.  For the purposes of this definition, the term“control” (including, with correlative meanings, the terms “controlled by” and “undercommon control with”) as used with respect to a Party means (a) in the case ofa corporate entity, direct or indirect ownership of voting securities entitledto cast more than fifty percent (50%) of the votes in the election of directorsor (ii) in the case of a non-corporate entity, direct or indirect ownership ofmore than fifty percent (50%) of the voting securities with the power to directthe management and policies of such entity.

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**1.3         ****“Collaboration Compound”** shall mean a chemical entity that issynthesized solely by a Party or jointly by the Parties (or on behalf of aParty or the Parties) in the course of the Research Program during the ResearchTerm that [***].

**1.4         ****“Collaboration Know-How”** shall mean any Information or Invention,to the extent directed  to aCollaboration Compound or a method of making or using a Collaboration Compound,generated or conceived solely by a Party (or on its behalf) or jointly by theParties (or on their behalf) in the course of the Research Program during theResearch Term.

**1.5         ****“Collaboration Patents”** shall mean Patents first filed after theEffective Date with claims or portions thereof, to the extent that theydescribe or claim a Collaboration Compound or a method of making or using aCollaboration Compound, where such Invention is conceived solely by a Party (oron its behalf) or jointly by the Parties (or on their behalf) in the course ofthe Research Program during the Research Term; provided that any Patent withthe same disclosure as an Idenix Patent described in Section 1.22(a) or aMetabasis Patent described in Section 1.38(a), such as a renewal, division,continuation (in whole), or request for continued examination (RCE), reissue,reexamination or the like, will be included in Section 1.22(a) or Section1.38(a), as applicable, rather than this Section 1.5.

**1.6         ****“Collaboration Technology”** shall mean Collaboration Know-How andCollaboration Patents.

**1.7         ****“Combination Therapy”** shall mean a fixed dose productcontaining more than one (1) active pharmaceutical ingredient.  [***]

**1.8         ****“Committee”** shall mean the joint research committeeestablished to facilitate the Research Program as more fully described inSection 2.1.

**1.9         ****“Confidential Information”** shall have the meaning given such termin Section 7.1.

**1.10       ****“Confidentiality Agreement”** shall mean the confidentialityagreement, dated March 29, 2006, by and between the Parties.

**1.11       ****“Control”**shall mean, with respect to anyInformation, Patent or other intellectual property right, possession by a Partyof the ability (whether by ownership, license or otherwise) to grant access, alicense or a sublicense to such Information or intellectual property rightwithout violating the terms of any agreement or other arrangement with anyThird Party (before taking into account the effect of any licenses granted bysuch Party to the other Party under this Agreement but after taking intoaccount the effect of Section 9.1(a)). For the avoidance of doubt, any Information, Patent or otherintellectual property right that a Party licenses under this Agreement to theother Party shall not be deemed to be under the “Control” of such other Party.

**1.12       ****“Development Candidate”** shall have the meaning provided inSection 4.1.

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**1.13       ****“Failed Development Candidate”** shall have the meaning provided inSection 5.4.

**1.14       ****“Field”** shall mean the treatment of chronichepatitis C viral infections in humans.

**1.15       ****“First Commercial Sale”**shall mean, with respect to any Product,the first sale in a country after the governing health regulatory authority ofsuch country has granted Regulatory Approval. For purposes of clarification, the first sale for end use or consumptionof a Product in a country after conditional approval has been granted willconstitute a First Commercial Sale for purposes of this Agreement.

**1.16       ****“FTE”** shall mean the equivalent of a full-time scientist’swork time over a [***] (including normal vacations, sick days and holidays).

**1.17       ****“HepDirect Technology”** shall mean (a) (i) any and all [***]and/or (ii) any method of making or using any of the foregoing (this clause(a), “HepDirect Base Technology”); which (b) [***].

**1.18       ****“Idenix Core Patent”** shall mean any Patent listed in ***Exhibit A***.

**1.19       ****“Idenix Indemnitee”** shall have the meaning provided inSection 11.2.

**1.20       ****“Idenix Know-How”** shall mean any (a) Information orInvention, to the extent directed to any Idenix Nucleoside or CollaborationCompound or a method of making or using an Idenix Nucleoside or CollaborationCompound, that is Controlled by Idenix as of the Effective Date,(b) Information or Invention, to the extent directed to any IdenixNucleoside or a method of making or using an Idenix Nucleoside, that firstbecomes Controlled by Idenix during the Research Term, and (c) Information orInvention, to the extent directed to a Collaboration Compound or a method ofmaking or using a Collaboration Compound, that first becomes Controlled byIdenix after the Research Term but prior to the First Commercial Sale of anyProduct that contains such Collaboration Compound.  Notwithstanding the foregoing,subsection (b) does not include any Information or Invention to the extentdirected to a Collaboration Compound or a method of making or using aCollaboration Compound.  For purposes ofclarity, Idenix Know-How does not include Metabasis Know-How.

**1.21       ****“Idenix Nucleoside”** shall mean either of the [***]nucleosides, the [***] is specifically identified on ***Schedule I*** tothe Research Plan as of the Effective Date and [***] shall be specified byIdenix in writing to Metabasis within [***] after the Effective Date, subjectto written approval by Metabasis, not to be unreasonably withheld or delayed,and ***Schedule I***to the Research Plan shall be automatically amended to include [***].

**1.22       ****“Idenix Patents”** shall mean (a) Patents with claims orportions thereof, to the extent directed to any Invention that is an IdenixNucleoside or Collaboration Compound or a

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method of making or using an Idenix Nucleoside or CollaborationCompound, where such Patents are Controlled by Idenix as of the Effective Date,(b) Patents with claims or portions thereof, to the extent directed to anyInvention that is an Idenix Nucleoside or a method of making or using an IdenixNucleoside, where such Invention first becomes Controlled by Idenix during theResearch Term (provided that any such Patent with the same disclosure as aPatent described in subsection (a), such as a renewal, division, continuation(in whole), or request for continued examination (RCE), reissue, reexaminationor the like, will be included in subsection (a) rather thansubsection (b)) and (c) Patents with claims or portions thereof, to theextent directed to any Invention that is a Collaboration Compound or a methodof making or using a Collaboration Compound, where such Invention first becomesControlled by Idenix after the Research Term but prior to the First CommercialSale of any Product that contains such Collaboration Compound.  Notwithstanding the foregoing,subsection (b), does not include any claims of such Patents or portionsthereof to the extent directed to any such Invention that is a CollaborationCompound or a method of making or using a Collaboration Compound.  For purposes of clarity, Idenix Patents donot include Metabasis Patents.  TheIdenix Patents existing on the Effective Date are listed on ***Exhibit C***.

**1.23       ****“Idenix Technology”** shall mean the Idenix Know-How andIdenix Patents.

**1.24       ****“IND”**shall mean an Investigational New Drug application,Clinical Study Application, Clinical Trial Exemption, or similar application orsubmission for approval to conduct human clinical investigations filed with orsubmitted to a Regulatory Authority in conformance with the requirements ofsuch Regulatory Authority.

**1.25       ****“Information”**shall mean all tangible and intangible(a) techniques, technology, practices, trade secrets, inventions (whetherpatentable or not), methods, processes of manufacture, intermediates, dosingregimens, formulations, knowledge, know-how, skill, experience, test data andresults (including pharmacological, toxicological and preclinical and clinicaltest data and results), analytical and quality control data, results ordescriptions, software and algorithms and (b) compositions of matter, cells,cell lines, assays, animal models and physical, biological or chemicalmaterial.

**1.26       ****“Invention”** shall mean any invention, conception,actual reduction to practice, constructive reduction to practice, process,method, use, composition of matter, article of manufacture, discovery orfinding, whether or not patentable.

**1.27       ****“Joint Invention”** shall mean any Invention conceivedjointly by the Parties (or on their behalf) in the course of the ResearchProgram during the Research Term; but excluding, in each case, CollaborationTechnology, Idenix Technology and Metabasis Technology.

**1.28       ****“Joint Patents”** shall mean Patents claiming any JointInvention.

**1.29       ****“Joint Patent Counsel”** shall have the meaning provided inSection 9.2(d)(i).

**1.30       ****“Joint Technology”**shall mean Joint Inventions and JointPatents.

**1.31       ****“Losses”** shall have the meaning provided inSection 11.1.

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**1.32       ****“Major European Market**” shall mean: (a) any [***] of thefollowing countries: [***]; or (b) [***].

**1.33       ****“Major Market”** shall mean the [***].

**1.34       ****“Materials”** shall have the meaning provided inSection 3.8.

**1.35       ****“Metabasis Core Patents”** shall mean any Patent listed in ***Exhibit B***.

**1.36       ****“Metabasis Indemnitee”** shall have the meaning provided inSection 11.1.

**1.37       ****“Metabasis Know-How”** shall mean any (a) Information orInvention, to the extent directed to HepDirect Technology or CollaborationCompound or a method of making or using HepDirect Technology or a CollaborationCompound, that is Controlled by Metabasis as of the Effective Date and(b) Information or Invention, to the extent directed to HepDirectTechnology or a method of making or using HepDirect Technology, that firstbecomes Controlled by Metabasis during the Research Term.  Notwithstanding the foregoing,subsection (b) does not include any Information or Invention to the extentdirected to a Collaboration Compound or a method of making or using aCollaboration Compound.  For purposes ofclarity, Metabasis Know-How does not include Idenix Know-How.

**1.38       ****“Metabasis Patents”** shall mean (a) Patents with claims orportions thereof, to the extent directed to any Invention that is HepDirectTechnology or Collaboration Compound or a method of making or using HepDirectTechnology or a Collaboration Compound, where such Patents are Controlled byMetabasis as of the Effective Date, and (b) Patents with claims or portionsthereof, to the extent directed to any Invention that is HepDirect Technologyor a method of making or using HepDirect Technology, where such Invention firstbecomes Controlled by Metabasis during the Research Term (provided that anysuch Patent with the same disclosure as a Patent described insubsection (a), such as a renewal, division, continuation (in whole), orrequest for continued examination (RCE), reissue, reexamination or the like,will be included in subsection (a) rather than subsection (b)).  Notwithstanding the foregoing,subsection (b) does not include any claims of such Patents or portionsthereof to the extent directed to any such Invention that is a CollaborationCompound or a method of making or using a Collaboration Compound.  For purposes of clarity, Metabasis Patents donot include Idenix Patents.  TheMetabasis Patents existing on the Effective Date are listed on ***Exhibit D***.

**1.39       ****“Metabasis Technology”** shall mean the Metabasis Know-How andMetabasis Patents.

**1.40       ****“NDA”** shall mean a New Drug Application (as more fullydefined in 21 C.F.R. 314.5 *et seq.*)and all amendments and supplements thereto filed with the FDA, or theequivalent application filed with any equivalent agency or governmentalauthority outside the United States of America (including any supra-nationalagency such as in the European Union), including all documents, data, and otherinformation concerning a pharmaceutical product which are necessary for gainingRegulatory Approval to market and sell such pharmaceutical product.

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**1.41       ****“Net Sales”** shall mean, with respect to any Product,the gross invoiced sales price of such Product by Idenix and Sublicensees toThird Parties which are not Sublicensees (provided that, if any Sublicensee isthe end user of such Product, the amount included in Net Sales shall be deemedto be the amount that would be billed to a Third Party end user in an arm’slength transaction), less the following deductions to the extent included inthe gross invoiced sales price for such Product or otherwise directly paid orincurred by Idenix or Sublicensees with respect to the sale of such Product:

**(a)          **normal and customary trade and quantity discounts, credits andallowances actually allowed and properly taken directly with respect to salesof such Product;

**(b)          **amounts repaid or credited by reason of rejections, recalls, returns,rebates, government mandated rebates, and allowances;

**(c)          **chargebacks and other amounts paid on sale or dispensing of suchProduct;

**(d)          **retroactive price reductions that are actually allowed or granted;

**(e)          **tariffs, duties, excise, sales, value-added or other taxes (other thantaxes based on income);

**(f)           **cash discounts for timely payment;

**(g)          **delayed ship order credits;

**(h)          **discounts pursuant to patient discount programs; and

**(i)           **freight, shipping and insurance charges.

Inthe event a Product (for purposes of this paragraph, the “relevant Product”)comprises a Development Candidate and an additional active pharmaceuticalingredient sold in a country in combination for use as a fixed-dose Product asa Combination Therapy, and both a Product comprising the Development Candidateas the sole active ingredient and a pharmaceutical product containing suchadditional active pharmaceutical ingredient as the sole active ingredient aresold separately in such country, the Net Sales for the relevant Product in suchcountry shall be calculated by multiplying Net Sales in such country (as wouldotherwise be determined in accordance with this definition of “Net Sales”(i.e., without giving effect to this paragraph or the immediately followingparagraph)) by the fraction A/(A+B), where A is the gross invoiced sales pricein such country of the Product comprising the Development Candidate as the soleactive ingredient (when sold separately from the Combination Therapy), and B isthe gross invoiced sales price in such country of the pharmaceutical productcomprising the additional active pharmaceutical ingredient as the sole activeingredient (when sold separately from the Combination Therapy). Notwithstandingthe foregoing, the fractional adjustment set forth in this paragraph shall notapply (and the fractional adjustment and procedures in the immediatelyfollowing paragraph shall apply instead) in the event actual sales of theseparate pharmaceutical product comprising the additional active pharmaceuticalingredient as the sole active ingredient are not more than incidental in suchcountry.

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Inthe event a Product (for purposes of this paragraph, the “relevant Product”)comprises a Development Candidate and an additional active pharmaceuticalingredient sold in a country in combination for use as a fixed-dose Product asa Combination Therapy, and either a Product comprising the DevelopmentCandidate as the sole active ingredient or the pharmaceutical productcomprising the additional active pharmaceutical ingredient as the sole activeingredient is not sold separately in such country, the Net Sales for therelevant Product in such country shall be calculated by multiplying Net Salesin such country (as would otherwise be determined in accordance with thisdefinition of “Net Sales” (i.e., without giving effect to this paragraph or theimmediately preceding paragraph)) by the fraction A/(A+B), where A is the fairmarket value in such country of the Product comprising the DevelopmentCandidate as the sole active ingredient (when or if it were (as applicable)sold separately from the Combination Therapy), and B is the fair market valuein such country of the pharmaceutical product comprising the additional activepharmaceutical ingredient as the sole active ingredient (when or if it were (asapplicable) sold separately from the Combination Therapy). For purposes ofcalculating the fraction specified in the immediately preceding sentence,Idenix shall make a written proposal to Metabasis, for its review and approval,of the fair market value of each component of such fraction, reasonably supportedby written documentation. If the Parties are unable to reach agreement on suchmatters, the provisions of Section 12.6 shall apply.

Forclarification purposes, there shall be no fractional adjustment in thecalculation of Net Sales (i.e., no effect shall be given to the immediatelypreceding two paragraphs) with respect to any Product comprising a DevelopmentCandidate that is sold together or promoted as a combination with a separatepharmaceutical product (including any interferon) for co-administration.

**1.42       ****“Notice Date”** shall have the meaning provided inSection 12.6(b).

**1.43       ****“Patents”**shall mean (a) all patents,certificates of invention, applications for certificates of invention, prioritypatent filings and patent applications, including without limitation patentapplications under the Patent Cooperation and the European Patent Convention,together with (b) any renewal, division, continuation (in whole or inpart), or request for continued examination (RCE) of any of such patents, certificatesof invention and patent applications, and any and all patents or certificatesof invention issuing thereon, and any and all reissues, reexaminations,extensions, divisions, renewals, substitutions, confirmations, registrations,revalidations, revisions, and additions of or to any of the foregoing, and anyforeign counterparts of any of the foregoing and any other patents and patentapplications claiming priority back to any of the foregoing.

**1.44       ****“Phase 1 Clinical Trial”**shall mean a human clinical trial in anycountry that is carried out to obtain data that can be submitted to the FDA insatisfaction of the requirements of 21 CFR 312.21(a).

**1.45       ****“Phase 2 Clinical Trial”** shall mean a human clinical trial in anycountry that is carried out to: (i) determine efficacy and dose range; and (ii)obtain data that can be submitted to the FDA in satisfaction of therequirements of 21 CFR 312.21(b). Notwithstanding the foregoing, Phase 2 Clinical Trial shall not includea phase 1b/2a clinical trial that includes a treatment period less than twelve(12) weeks in length.

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**1.46       ****“Phase 3 Clinical Trial”** shall mean a pivotal human clinicaltrial in any country that is carried out to obtain data that can be submittedto the FDA in satisfaction of the requirements of 21 CFR 312.21(c).

**1.47       ****“Process Chemistry Know-How”**shall mean any Information or Invention,to the extent directed to a process chemistry improvement to HepDirectTechnology, that first becomes Controlled by Idenix following receipt of theinformation with respect to a Development Candidate pursuant to Section 3.4 butprior to the First Commercial Sale of any Product that contains suchDevelopment Candidate.

**1.48       ****“Process Chemistry Patents”** shall mean Patents with claims orportions thereof, to the extent directed to any Invention that is a processchemistry improvement to HepDirect Technology, that first becomes Controlled byIdenix following receipt of the information with respect to a DevelopmentCandidate pursuant to Section 3.4 but prior to the First Commercial Sale of anyProduct that contains such Development Candidate.

**1.49       ****“Process Chemistry Technology”**shall mean Process Chemistry Know-How andProcess Chemistry Patents.

**1.50       ****“Product”** shall mean any preparation in final formcontaining a Development Candidate for sale by prescription, over-the-counteror any other method.

**1.51       ****“Project Leader”** shall have the meaning provided inSection 2.5.

**1.52       ****“Proof of Concept”** shall have the meaning provided in ***Schedule II*** tothe Research Plan.

**1.53       ****“Proposed Resolution Deadline”** shall have the meaning provided inSection 12.6(c).

**1.54       ****“Regulatory Approval”**shall mean any and all approvals(including price and reimbursement approvals, if required), licenses,registrations, or authorizations of any Regulatory Authority in a particularjurisdiction that are necessary for the manufacture, use, storage, import,transport and/or sale of a Product in such jurisdiction in accordance withapplicable laws.

**1.55       ****“Regulatory Authority”** shall mean any national or supranationalgovernmental authority, including, without limitation, the FDA and the EMEA,that has responsibility in any country or other regulatory jurisdiction overthe development and/or commercialization of Products.  For purposes of this Agreement, “FDA” shallmean the U.S. Food and Drug Administration or any successor agency, and “EMEA”shall mean the European Medicines Agency or any successor agency.

**1.56       ****“Research Plan”**means the plan (the initial form of whichhas been agreed upon in writing by the Parties as set forth in the letteragreement dated as of the Effective Date) that sets out the research work to beperformed by Metabasis and Idenix in conducting the Research Program, as suchplan may be amended or modified by the Committee or by mutual written agreementof the Parties as contemplated under this Agreement.

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**1.57       ****“Research Program”** shall mean the research activitiesundertaken by either or both of the Parties as set forth in Article 3 and the Research Plan.

**1.58       ****“Research Term”** shall mean the duration of the ResearchProgram, and **“Initial Research Term**”and **“Extended Research Term”** shallhave the respective meanings given such terms in Section 3.6(a).

**1.59       ****“Royalty-Extending Patent”** shall mean any Specific Claim if alicense to such Specific Claim granted pursuant to Section 4.2(a)(iii) providesIdenix or its Sublicensee with market exclusivity for the applicableDevelopment Candidate or Product and such market exclusivity is due solely tothe license granted to such Specific Claim.

**1.60       ****“Royalty Term”**shall mean, in the case of any Product inany country, the period of time commencing on the First Commercial Sale of suchProduct in such country and ending upon the later of (a) [***] after the dateof First Commercial Sale of such Product in such country, and (b) theexpiration of the last to expire of (i) the Metabasis Patents, Idenix Patents,Collaboration Patents, or Joint Patents containing a Valid Claim that would,absent ownership of or a license to such Patent, be infringed by the use orsale of such Product or the Development Candidate therein or by the manufactureof such Product or the Development Candidate therein (if ownership of or alicense to such a Patent containing a Valid Claim of method of manufacturingsuch Development Candidate or Product would provide market exclusivity for theapplicable Product) or (ii) any Royalty-Extending Patents.

**1.61       ****“Specific Claims”** shall have the meaning provided inSection 4.2(a)(iii).

**1.62       ****“Sublicensee”** shall mean an Affiliate or Third Partyto which Idenix has (a) sublicensed some or all of Metabasis Technology orCollaboration Technology or any Royalty-Extending Patent,**or (b) licensed some or all of IdenixTechnology or Joint Technology to develop, make, have made, use, sell, havesold, offer for sale or import Development Candidates and Products in the Fieldduring the Term.

**1.63       ****“Term”**shall have the meaning provided inSection 10.1.

**1.64       ****“Territory”** shall mean worldwide.

**1.65       ****“Third Party”** shall mean an entity other than Idenixand its Affiliates, and Metabasis and its Affiliates.

**1.66       ****“Third Party Patent”** shall have the meaning provided inSection 5.5(b)(iii).

**1.67       ****“Title 11”** shall have the meaning provided inSection 10.7.

**1.68       ****“Valid Claim”**shall mean a claim of (a) an issued andunexpired patent or a supplementary protection certificate, which claim has notbeen held invalid or unenforceable by a court or other government agency ofcompetent jurisdiction from which no appeal can be or has been taken and hasnot been held or admitted to be invalid or unenforceable through re-examinationor disclaimer, opposition procedure, nullity suit or otherwise, or (b) apending patent application; *provided,however*, that if a claim of a pending patent application shall not

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have issued within [***] (or in Japan, [***] after theearliest filing date from which such claim takes priority, such claim shall notconstitute a Valid Claim for the purposes of this Agreement unless and until apatent issues with such claim.

**2.****                                     ****RESEARCHPROGRAM GOVERNANCE**

**2.1         ****Joint Research Committee.** Promptly after the Effective Date, the Parties will form a JointResearch Committee (the ***“Committee”***)composed of an equal number of representatives of each of Idenix andMetabasis.  One member of the Committeeshall be selected to act as the chairperson of the Committee, with eachchairperson acting for a term of twelve (12) months.  The chairperson shall be selected alternatelyby Metabasis and Idenix, and [***] shall designate the first chairperson.  The purpose of the Committee is to ensurethat the goals and purpose of this Agreement are being carried out in a timelyand effective manner.

**2.2         ****Meetings.** The Committee shall meet at least [***] timesper year during the Research Term or at such greater frequency as the Committeeagrees.  Such meetings may be conductedby videoconference, teleconference or in person, as agreed by the Parties, andthe Parties shall agree upon the time of meetings.  In-person meetings shall alternate betweenthe facilities of Idenix in Cambridge, Massachusetts, and the facilities ofMetabasis in La Jolla, California.  No Committee meeting may be conducted unless atleast one representative of each Party is participating.  Each Party shall bear its own expensesrelated to the attendance of such meetings by its representatives.  A reasonable number of additionalrepresentatives of a Party may attend meetings of the Committee in a non-votingcapacity.

**2.3         ****Minutes. **The hosting Party shall have responsibility forpreparing definitive minutes of each Committee meeting, a draft of which shallbe circulated for comment to all members of the Committee within ten(10) business days after the relevant meeting.  Such minutes shall provide a description, inreasonable detail, of the Research Program progress to date, and of thediscussions at the meeting, a list of any actions or determination approved bythe Committee and any disagreements not resolved by the Committee.  The Project Leaders shall discuss any commentson such minutes and finalize the minutes by no later than 30 business daysafter the meeting.  Any disagreement onthe minutes shall be resolved in accordance with Section 2.4.

**2.4         ****Committee Decision-Making.** All decisions of the Committee shall be unanimous, with therepresentatives of each Party collectively having one (1) vote.  If the Committee is unable to decide orresolve unanimously any matter properly presented to it for action, then at thewritten request of either Party, the issue shall be referred to Metabasis’Executive Vice President of Research and Development and Idenix’s Senior VicePresident, Biology, who shall attempt in good faith to resolve such issue aspromptly as practicable.  If suchofficers are unable to resolve such issue within [***], then at the writtenrequest of either Party, the issue shall be referred to the Chief ExecutiveOfficer of Metabasis and the Chief Executive Officer of Idenix forresolution.  Such officers of the Partieswill meet promptly thereafter in order to resolve such issue as promptly as practicable.

**2.5         ****Project Leaders**. Idenix and Metabasis each shall appoint a person (a ***“Project Leader”***)from the Committee to coordinate its part of the Research Program.  The Project

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Leaders shall be the primary contact between theParties with respect to the Research Program. Each Party shall notify the other Party as soon as practicable uponchanging this appointment.

**3.****                                     ****RESEARCHPROGRAM**

**3.1         ****General. **Metabasis and Idenix shall engage in the ResearchProgram upon the terms and conditions set forth in this Agreement.  The activities to be undertaken in the courseof Research Program are set forth in the Research Plan which may be amendedfrom time to time upon the mutual written agreement of authorizedrepresentatives of the Parties.

**3.2         ****Conduct of Research. **Subject to the terms and conditions of this Agreement,each Party shall be responsible for managing and controlling its respectiveresearch obligations under the Research Plan. Each Party shall conduct the Research Program in good scientific manner,and in compliance in all material respects with all requirements of applicablelaws, rules and regulations.  Each Partyhereby certifies that it will not and has not employed or otherwise used in anycapacity the services of any person debarred under Section 21 USC 335a inperforming any services hereunder.  EachParty shall proceed diligently and in a timely manner with the work set out inthe Research Program by using commercially reasonable efforts to carry out theactivities assigned to such Party under the Research Program with sufficientskills and experience as are required to accomplish the Research Program inaccordance with the terms of this Agreement and Research Plan.

**3.3         ****Research Commitment; Metabasis FTEs.** Duringthe Research Term, each Party shall use its commercially reasonable efforts tocarry out the activities assigned to such Party under the Research Program inaccordance with such plan and the terms and conditions of this Agreement.  Without limiting the generality of theforegoing, Metabasis shall devote to the performance of its responsibilitiesunder the Research Plan [***] FTEs per year during the Research Term, all ofwhom shall be funded by Idenix in accordance with Section 5.2.  For purposes of clarification, in no eventshall Metabasis be obligated to devote to the Research Program more than thenumber of FTEs being funded by Idenix under this Agreement.

**3.4         ****Exchange of Information. **Upon execution of this Agreement, and from time totime as necessary during the Research Term, Metabasis shall disclose to Idenixall Collaboration Know-How not previously disclosed and such Metabasis Know-Howas is reasonably necessary, in Metabasis’ reasonable judgment, for theperformance by Idenix of its responsibilities under the Research Program.  Following designation of a DevelopmentCandidate pursuant to Section 4.1, Metabasis shall disclose to Idenix allCollaboration Know-How regarding such Development Candidate not previouslydisclosed and such Metabasis Know-How as is reasonably necessary for themanufacture, use (including use for development) or sale of DevelopmentCandidates and Products in the Field. Upon execution of this Agreement, and from time to time as necessaryduring the Research Term, Idenix shall disclose to Metabasis all CollaborationKnow-How not previously disclosed and such Idenix Know-How as is reasonablynecessary for the performance by Metabasis of its responsibilities under theResearch Program.  Nothing herein shallrequire either Party to disclose information that is subject to *bona fide* confidentiality obligations to aThird Party.

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**3.5         ****Records and Reports. **Metabasis and Idenix shall each maintain records, insufficient detail and in good scientific manner appropriate for patent andregulatory purposes, which shall fully and properly reflect all work done andresults achieved in the performance of the Research Program by such Party.  Within [***] during the Research Term, eachParty shall provide to the other Party a written progress report which shallsummarize (a) with respect to reports provided by Metabasis, data and resultsregarding the Collaboration Compound with respect to each Idenix Nucleosidethat Metabasis identifies as most likely to meet the Proof of Concept orDevelopment Candidate criteria and (b) with respect to reports provided byIdenix, test data and results regarding Collaboration Compounds tested byIdenix to determine whether or not such Collaboration Compounds meet the Proofof Concept or Development Candidate criteria. Without limiting the generality of the foregoing, each such progressreport will disclose any Collaboration Technology that such Party works onduring such calendar quarter.

**3.6         ****Research Term.**

**(a)          ****Research Term.** Except as otherwise provided in Article 10, the Research Term shallcommence on the Effective Date****andcontinue for a period of two (2) years (the ***“Initial Research Term”***).  Thereafter, the Parties may extend theResearch Term by mutual written agreement of the authorized representative ofthe Parties, and shall, in such case, amend the Research Plan as applicable.  Any such extension of the Research Term shallbe referred to herein as an ***“Extended Research Term.”***

**(b)          ****Early Termination.** Notwithstanding anything to the contrary in this Section 3.6,Idenix may, with or without cause and in its sole discretion, terminate theResearch Term:

**(i)           **effective as of the first anniversary of the EffectiveDate upon written notice to Metabasis given no later than [***] prior to thefirst anniversary of the Effective Date; or

**(ii)          **at any time after designation of the first DevelopmentCandidate in accordance with Section 4.1 and payment of the correspondingmilestone payment specified in Section 5.4, by providing Metabasis with[***] written notice to such effect.

**3.7         ****Use of Subcontractors. **Each Party shall be entitled to utilize the service ofThird Parties to perform their respective Research Program activities only uponthe prior written consent of the other Party (not to be unreasonably withheld)or as specifically set forth in the Research Plan.  Notwithstanding any such consent, each Partyshall remain at all times responsible for the performance of its respectiveresponsibilities under the Research Program and shall obtain the writtenagreement of each such Third Party, prior to the time such Third Partyinitiates work, to assign ownership of Inventions made in the course ofResearch Program activities to such Party, and such Party will make suchfurther assignment of such Inventions as provided under Article 9 hereof.

**3.8         ****Materials. **In order to facilitate the Research Program, eitherParty may provide to the other Party certain biological materials or chemicalcompounds Controlled by the

 

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supplying Party, including, but not limited to,Collaboration Compounds (collectively, ***“Materials”***) for use by the other Party infurtherance of the Research Program. Except as otherwise provided under this Agreement, all such Materialsdelivered to the other Party will remain the sole property of the supplyingParty, will be used only in furtherance of the conduct of the Research Programand, if applicable, the development, manufacture or commercialization ofProducts in accordance with this Agreement, will not be used or delivered to orfor the benefit of any Third Party without the prior written consent of thesupplying Party, and will be used in compliance with all applicable laws, rulesand regulations.  The Materials suppliedunder this Agreement must be used with prudence and appropriate caution in anyexperimental work because not all of their characteristics may be known.  Except as expressly set forth herein, THEMATERIALS ARE PROVIDED “AS IS” AND WITHOUT ANY REPRESENTATION OR WARRANTY,EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED WARRANTY OFMERCHANTABILITY OR OF FITNESS FOR ANY PARTICULAR PURPOSE OR ANY WARRANTY THATTHE USE OF THE MATERIALS WILL NOT INFRINGE OR VIOLATE ANY PATENT OR OTHERPROPRIETARY RIGHTS OF ANY THIRD PARTY.

**4.****                                     ****DESIGNATIONOF DEVELOPMENT CANDIDATES; LICENSE GRANTS; DEVELOPMENT AND COMMERCIALIZATION**

**4.1         ****Designation of Development Candidate.** At any time during the Research Term or within[***] after its expiration, Idenix may, by written notice to Metabasis,designate one (1) or more Collaboration Compounds that possess the propertiesspecified in ***Schedule III***to the Research Plan as ***“DevelopmentCandidates”*** for purposes of this Agreement.

**4.2         ****License Grants.**

**(a)          ****By Metabasis.**

**(i)           ****Collaboration Technology and JointTechnology.**  Subject to the terms and conditions of thisAgreement, Metabasis hereby grants to Idenix an exclusive (even as toMetabasis), royalty-bearing license in the Territory, with the right tosublicense through multiple tiers of sublicense, under Metabasis’ interest inCollaboration Technology and Joint Technology, solely (A) to performIdenix’s obligations under the Research Program during the Research Term and(B) to develop, make, have made, use, sell, have sold, offer for sale andimport Development Candidates and Products in the Field during the Term; *provided, however,* that Metabasis retainssuch rights under Metabasis’ interest in Collaboration Technology and JointTechnology solely as are necessary to perform its obligations under theResearch Program.

**(ii)          ****Metabasis Technology.** Subject to the terms and conditions of this Agreement,(A) Metabasis hereby grants to Idenix a non-exclusive,royalty-bearing license in the Territory, without the right to sublicense(except that Idenix may subcontract), under Metabasis Technology Controlled byMetabasis solely to perform Idenix’s obligations under the Research Program duringthe Research Term, and (B) Metabasis hereby grants to Idenix a non-exclusive,royalty-bearing license in the Territory, with the right to sublicense asdescribed below through multiple tiers of sublicense, under MetabasisTechnology Controlled by

 

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Metabasis solely to develop, make, have made, use,sell, have sold, offer for sale and import Development Candidates and Productsin the Field during the Term.  Idenixshall have the right to sublicense its rights under Section 4.2(a)(ii)(B)only in conjunction with a sublicense of its rights underSection 4.2(a)(i), and each such sublicense underSection 4.2(a)(ii)(B) shall have the same scope as the sublicense grantedto the same Sublicensee under Section 4.2(a)(i) (provided, however, that,if the sublicense granted to the same Sublicensee under Section 4.2(a)(i)were to expire solely due to expiration of the Collaboration Technology andJoint Technology with respect to the relevant Product and relevant countryprior to the expiration of the Metabasis Technology with respect to suchProduct and country, the sublicense under Section 4.2(a)(ii)(B) shall continuefor the remainder of the Royalty Term with respect to such Product andcountry).

**(iii)        ****Limited License Grant.** With respect to each Development Candidate, in the event that thedevelopment, making, having made, use or import of such Development Candidateor the development, making, having made, use, offer for sale, sale, having soldor import by Idenix or Sublicensees of such Development Candidate wouldinfringe during the Term a Valid Claim of any issued Patent with claims orportions thereof to the extent directed to any Invention that is HepDirect BaseTechnology, where such Invention first becomes Controlled by Metabasis afterthe Research Term but prior to the First Commercial Sale of such DevelopmentCandidate (provided that any such Patent with the same disclosure as a Patentincluded in Metabasis Patents, Collaboration Patents or Joint Patents, such asa renewal, division, continuation (in whole), or request for continuedexamination (RCE), reissue, reexamination or the like, will be included inMetabasis Patents, Collaboration Patents or Joint Patents, and not subject tothis Section 4.2(a)(iii)) (the ***“Specific Claims”***), which Patent is not aMetabasis Patent, Collaboration Patent or Joint Patent, then,  subject to the terms and conditions of thisAgreement, Metabasis hereby grants to Idenix, a non-exclusive, royalty-bearing(included within the royalties as set forth in Section 5.5) license in theTerritory, including the right to sublicense as described below throughmultiple tiers of sublicense, under such Specific Claims solely to develop,make, have made, use, sell, offer for sale, have sold or import such DevelopmentCandidate in the Field during the Term. Idenix shall have the right to sublicense its rights under this Section4.2(a)(iii) only in conjunction with a sublicense of its rights under Section4.2(a)(i), and each sublicense under this Section 4.2(a)(iii) shall have thesame scope as the sublicense granted to the same Sublicensee under Section4.2(a)(i) (provided, however, that, if the sublicense granted to the sameSublicensee under Section 4.2(a)(i) were to expire solely due toexpiration of the Collaboration Technology and Joint Technology with respect tothe relevant Development Candidate and relevant country prior to the expirationof the Specific Claims with respect to such Development Candidate and country,the sublicense under this Section 4.2(a)(iii) shall continue for the remainderof the Royalty Term with respect to such Development Candidate andcountry).  Following designation byIdenix of each Development Candidate and continuing until First Commercial Saleof such Development Candidate, Metabasis shall not grant to any Affiliate orThird Party any right or license under any applicable Specific Claim such thatMetabasis would no longer Control the Specific Claim.

**(b)          ****By Idenix.**Subject to the terms and conditions ofthis Agreement, Idenix hereby grants to Metabasis (i) a non-exclusive,royalty-free license in the Territory, without the right to sublicense, underIdenix Technology solely to perform Metabasis’ obligations under the ResearchProgram during the Research Term, and (ii) a non-exclusive, royalty-free,perpetual license, with the right to sublicense through multiple tiers ofsublicense, under Process

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Chemistry Technology to develop, make, have made, use, sell, have sold,offer for sale and import products other than Collaboration Compounds,Development Candidates and Product.

**4.3         ****Development and Commercialization.** Subject to the terms and conditions of thisAgreement, Idenix shall control, and be solely responsible for the costsassociated with, the worldwide preclinical and clinical development,registration and commercialization of Development Candidates and Products.  Without limiting the generality of theforegoing, Idenix shall be responsible for the worldwide supply of allDevelopment Candidates and Products necessary for the foregoing activities.

**4.4         ****Diligence Obligations.* ***Idenix agrees to use commerciallyreasonable efforts (directly and/or through one or more Sublicensees) todevelop for sale in the Major Markets and commercialize in each of the MajorMarkets at least [***] Development Candidate or Product in the Field.

**(a)          **In the event that Idenix: (i) is not developingfor sale in the Major Markets or commercializing in a particular Major Marketat least [***] Development Candidate or Product in the Field, or(ii) decides that it will not develop for sale in the Major Markets orcommercialize in a particular Major Market at least [***] Development Candidateor Product in the Field, then Idenix shall provide Metabasis with promptwritten notice thereof.

**(b)          **In addition, if Metabasis in good faith believes thatIdenix is not using its commercially reasonable efforts to develop for sale inthe Major Markets or commercialize in a particular Major Market at least [***]Development Candidate or Product in the Field, Metabasis may provide Idenixwith written notice thereof, in which event Idenix will have [***] after thedate of such notice in which to reasonably demonstrate to Metabasis that Idenixis meeting such diligence obligation.

**(c)          **If Idenix provides notice to Metabasis pursuant toSection 4.4(a) that it is not and will not meet its diligence obligation withrespect to one or more Major Markets, or fails to reasonably demonstrate toMetabasis pursuant to Section 4.4(b) that it is meeting its diligenceobligation with respect to [***] or more Major Markets within [***] afternotice from Metabasis of failure to meet such diligence obligation, then (i)this Agreement shall terminate with respect to such Major Market(s) in whichIdenix is not using its commercially reasonable efforts to develop orcommercialize at least [***] Development Candidate or Product in the Field, and(ii) ***“Territory”***shall be redefined to be [***].  Withrespect to Section 4.4(a), Idenix shall not be in breach of this Agreementunder Section 10.2(b) unless it provides notice to Metabasis pursuant toSection 4.4(a) that it is not and will not conduct development andcommercialization of at least [***] Development Candidate or Product in theField in at least one Major Market.  Withrespect to Section 4.4(b), Idenix shall not be in breach of this Agreementunder Section 10.2(b) unless Metabasis in good faith believes that Idenix isnot using its commercially reasonable efforts to develop or commercialize atleast [***] Development Candidate or Product in the Field in at least [***]Major Market, Metabasis provides Idenix with written notice thereof, and Idenixfails to reasonably demonstrate to Metabasis within [***] after the date ofsuch notice that Idenix is meeting such diligence obligation in at least [***]of the Major Markets.

 

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**4.5         ****Disclosure Regarding Idenix Efforts.** Idenix will keep Metabasis appropriately informed about Idenix’sresearch, development, clinical trial progress and commercialization effortswith respect to Development Candidates and Products.  Without limiting the generality of theforegoing, Idenix shall provide Metabasis with prompt written notice of thefollowing:

**(a)          **filing of any IND for a Development Candidate or Product;

**(b)          **initiation of a Phase 1 Clinical Trial, Phase 2 ClinicalTrial or Phase 3 Clinical Trial of a Development Candidate or Product;

**(c)          **filing of any application for Regulatory Approval with respect to anyProduct;

**(d)          **receipt of Regulatory Approval for any Product; and

**(e)          **any other significant development or commercialization plans,activities or results with respect to Development Candidates or Products.

In addition, Idenix shallprovide Metabasis with [***] written reports summarizing Idenix’s developmentand commercialization efforts with respect to Development Candidates andProducts during the applicable [***] period. The provisions of thisSection 4.5 shall survive expiration or termination of the Research Termfor so long as any license granted to Idenix under Section 4.2(a) remainsin effect.

**4.6         ****Negative Covenants; NoImplied Licenses.**

**(a)          **Idenix hereby covenants that it will not, directly orindirectly (including through any Sublicensee), conduct clinical development orcommercialization activities pursuant to this Agreement with respect to anyCollaboration Compound that has not been designated or deemed a DevelopmentCandidate pursuant to this Agreement during the Term and Idenix furtheracknowledges and agrees that it has no right or license under MetabasisTechnology, Collaboration Technology or Joint Technology to do any of theforegoing and will not practice any Idenix Technology Controlled by Idenix,which is directed to any Collaboration Compound, the method of manufacture ofany Collaboration Compound or method of use of any Collaboration Compound, todo any of the foregoing.  In addition,during the Term Idenix shall not use or practice any Metabasis Technology orSpecific Claims except as expressly permitted under this Article 4.  In no event shall Idenix (i) create orsynthesize, or attempt to create or synthesize (either itself or through anAffiliate or Third Party), outside of the Research Program during the ResearchTerm, any chemical entity that [***]; or (ii) create or synthesize, or attemptto create or synthesize (either itself or through an Affiliate or Third Party),after expiration or termination of the Research Term, any chemical entity that[***]; *provided, however,* thatthe restrictions set forth in Section 4.6(a)(i) and (ii) shall not apply to thesynthesis of Development Candidates or Products for so long as any licensegranted to Idenix under Section 4.2(a) remains in effect.  If Idenix creates or synthesizes (eitheritself or through an Affiliate or Third Party) any chemical entity that

 

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[***] in breach of this Section 4.6(a), such chemical entity shallautomatically be deemed to be a Collaboration Compound and DevelopmentCandidate subject to the terms of this Agreement.

**(b)          **Metabasis and its Affiliates shall not, and shall notgrant to any Third Party any rights to, use or practice Metabasis Technology orMetabasis’ interest in Collaboration Technology or Joint Technology withrespect to the Idenix Nucleosides, the Collaboration Compounds, DevelopmentCandidates or Products during the Term, other than solely as necessary tofulfill Metabasis’ obligations under the Research Plan during the ResearchTerm.  Notwithstanding any otherprovision of this Agreement to the contrary, but subject to the licensesgranted by Metabasis to Idenix under Section 4.2(a), Metabasis at all timesreserves the exclusive and unrestricted right to use or practice, and to grantits Affiliates and Third Parties the right to use or practice, MetabasisTechnology for any purpose other than the development, manufacture orcommercialization of the Idenix Nucleosides, the Collaboration Compounds,Development Candidates or Products.  Inaddition, during the Term Metabasis shall not use or practice any IdenixTechnology except as expressly permitted under this Article 4.  In no event shall Metabasis create orsynthesize, or attempt to create or synthesize (either itself or through anAffiliate or Third Party), outside of the Research Program during the ResearchTerm, any chemical entity that [***]; or (ii) create or synthesize, or attemptto create or synthesize (either itself or through an Affiliate or Third Party),after expiration or termination of the Research Term, any chemical entity that[***].

**(c)          **No right or license under any Patents or Informationof either Party is granted or shall be granted by implication.  All such rights or licenses are or shall begranted only as expressly provided in the terms of this Agreement.

**5.****                                     ****PAYMENTS**

**5.1         ****Upfront Fee.** Idenix shall make a one-time, non-refundable, non-creditablepayment to Metabasis of $2,000,000 within fifteen (15) days after theEffective Date.

**5.2         ****Research Program FTE Funding.** In consideration for Metabasis’ performance of its obligations under theResearch Program, upon the terms and conditions contained herein, Idenix shallfund each FTE provided by Metabasis pursuant to Section 3.3 at the rate of[***], which shall be subject to adjustment on an annual basis as of January 1of each year, beginning in 2007, by a factor which reflects any increase in theConsumer Price Index for San Diego County, California as reported as of January1 in each applicable year thereafter when compared to the comparable statisticfor January 1 of the preceding year. During the Research Period, the first payment under this Section 5.2shall be made within [***] after the receipt by Idenix of an invoice fromMetabasis for payment of FTE funding for the period from the Effective Date toDecember 31, 2006, and each subsequent payment shall be made on a quarterly basiswithin a period of [***] after the receipt by Idenix of an invoice fromMetabasis for payment of FTE funding for that quarterly

 

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period.  Eachinvoice shall set forth information regarding FTEs used by Metabasis on theResearch Program during the applicable quarter.

**5.3         ****Proof of Concept Milestone. **Within [***] after written notice by Metabasis toIdenix of the achievement of the first Proof of Concept, Idenix shall pay toMetabasis a one-time milestone payment of [***].  This one-time milestone payment shall be paidonly once regardless of the number of times that Proof of Concept is achievedby one or more Collaboration Compounds.

**5.4         ****Milestone Payments. **Idenix shall pay to Metabasis each of the milestonepayments set forth below (whether such milestone is achieved by Idenix or aSublicensee): 
| **Milestone  Event** | ** ** | **Milestone  Payment** |
|----------------------|------------|------------------------|
| [***]                |       |                   |
|                 |       |                   |
|                 |       |                   |
|                 |       |                   |
|                 |       |                   |
|                 |       |                   |
|                 |       |                   |

 

*              [***]

Each ofthe milestone payments described in this Section 5.4 shall be payable only[***] for each Idenix Nucleoside, [***] which are developed or the number ofindications for which Development Candidates or Products based on such IdenixNucleoside are developed or commercialized. Additionally, to the extent that any milestone payment has been made withrespect to a Development Candidate or Product based on a particular IdenixNucleoside that is subsequently deemed a Failed Development Candidate, [***] inconnection with the development or regulatory approval of a substitute orreplacement Development Candidate or Product based on such IdenixNucleoside.  A ***“Failed Development Candidate”***is deemed to mean a Development Candidate or Product based on a particularIdenix Nucleoside that either: (i) fails to meet regulatory criteria forfurther development or does not obtain approval for commercialization; or (ii)the Parties mutually agree does not meet commercial criteria for furtherdevelopment.

 

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Idenix shall notify Metabasis in writing within [***] after the achievementof each milestone, and shall make the appropriate milestone payment toMetabasis within such [***] period.  If,for any reason, a Development Candidate or Product based on a particular IdenixNucleoside reaches a particular milestone specified above without havingachieved [***] preceding milestones from among the [***] milestones listedabove, then upon the achievement of such milestone, both the milestone paymentapplicable to such milestone and the milestone payment(s) applicable to suchpreceding unachieved milestone(s) shall be due and payable within [***] afterthe achievement of such milestone.

**5.5         ****Royalties.**

**(a)          **Idenix shall pay to Metabasis royalties on worldwideannual Net Sales of Products by Idenix and Sublicensees at the following rates:
| **Annual Net  Sales**                     | ** ** | **Royalty Rate** |
|-------------------------------------------|------------|------------------|
| Portion of  annual Net Sales <[***]    |       | [***]            |
| Portion of  annual Net Sales ≥[***] |       | [***]            |
| Portion of  annual Net Sales ≥[***] |       | [***]            |
| Portion of  annual Net Sales ≥[***] |       | [***]            |

Royalties under thisSection 5.5 shall be payable on a Product-by-Product andcountry-by-country basis for a period equal to the Royalty Term for suchProduct in such country.

**(b)           Reductions.**

**(i)           ****Compulsory Licenses.** If any compulsory license is granted by Idenix or its Sublicensee to aThird Party with respect to a Product in any country through the order, decreeor grant of a Regulatory Authority in such country, authorizing such ThirdParty to manufacture, use, sell, offer for sale or import such Product in suchcountry, which compulsory license provides for a royalty rate lower than theapplicable royalty rate(s) set forth in Section 5.5(a), as adjusted pursuant toSections 5.5(b)(ii) and (iii), then the royalty rate to be paid by Idenix toMetabasis on Net Sales in that country for such Product pursuant to Section5.5(a) shall be reduced to that compulsory license rate for the period duringwhich such compulsory license is in effect. Idenix shall use commercially reasonable efforts to oppose the grantingof any such compulsory license, and, if any such compulsory license is granted,to limit such compulsory license to the extent possible. Further, no royaltyshall be paid on (i) Product that Idenix provides at or below cost to agovernment or institution to address a health crisis or emergency, or (ii) Productthat Idenix provides at cost or below on a humanitarian or charitable basis.

**(ii)          ****Expiration of Valid Claims.** On a Product-by-Product and country-by-country basis, royalty amountsotherwise payable by Idenix to Metabasis pursuant to Section 5.5(a), as may beadjusted pursuant to Section 5.5(b)(iii), on Net Sales of any Product duringany portion of the Royalty Term remaining after the expiration of the last toexpire of the applicable (A) Metabasis Patents, Idenix Patents, CollaborationPatents, Joint Patents and containing a Valid Claim that would, absentownership of or a license to such Patent, be infringed by the use or sale ofsuch Product or the Development Candidate therein or by the 

 

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manufacture of such Productor the Development Candidate therein (if ownership of or a license to such aPatent containing a Valid Claim of method of manufacturing such DevelopmentCandidate or Product provides market exclusivity for the applicable Product)and (B) any Royalty-Extending Patents, shall be reduced by [***]; *provided, however,* that in no event shallany royalty payment for any Product in any country in any calendar quarter bereduced to less than [***] of the royalty payment otherwise payable by Idenixto Metabasis pursuant to Section 5.5(a) (without taking into account anyadjustment pursuant to Sections 5.5(b)) as a result of the credits underthis Section 5.5(b)(ii) and Section 5.5(b)(iii).

**(iii)        ****Credit for Payment of Royalties forNecessary Third Party Issued Patents.**  On aProduct-by-Product and country-by-country basis, if Idenix or its Sublicenseedetermines that a license to any issued Patent of a Third Party (that is not aSublicensee of Idenix with respect to such Product in such country) (a ***“Third Party Patent”***)is necessary to allow Idenix and Sublicensees to practice Metabasis Technologypursuant to the licenses granted to Idenix under Section 4.2(a)(ii) ofthis Agreement, then Idenix may elect, after consultation with its * *outsidePatent counsel and Metabasis, to obtain a license to such Third Party Patent atits own expense.  If Idenix obtains sucha license, Idenix shall be entitled to credit [***] of the royalties paid tosuch Third Party for the license to such Third Party Patent from the royaltypayment otherwise payable by Idenix to Metabasis pursuant to Section 5.5(a), asmay be adjusted pursuant to Section 5.5(b)(ii); *provided, however,* that in no event shall any royaltypayment for any Product in any country in any calendar quarter be reduced to lessthan [***] of the royalty payment otherwise payable by Idenix to Metabasispursuant to Section 5.5(a) (without taking into account any adjustmentpursuant to Sections 5.5(b)) as a result of the credits under Section5.5(b)(ii) and this Section 5.5(b)(iii). For clarification, Idenix or its Sublicensee is responsible, at its ownexpense, for all other payments to Third Parties in connection with obtainingrights to intellectual property rights necessary or desirable for thedevelopment, manufacture or commercialization of any Development Candidate orProduct by Idenix or Sublicensees.

**6.****                                     ****PAYMENT;RECORDS; AUDITS**

**6.1         ****Payment; Reports. **Royalties shall be calculated and reported for eachcalendar quarter.  All payments due toMetabasis under this Agreement shall be paid within [***] after the end of eachcalendar quarter, unless otherwise specifically provided herein.  Each payment shall be accompanied by a reportof Net Sales of Products by Idenix and Sublicensees in sufficient detail topermit confirmation of the accuracy of the payment made, including, withoutlimitation and on a country-by-country basis, the number of Products sold, thegross sales and Net Sales of such Products, the royalties payable, the methodused to calculate the royalties, and the exchange rates used.

**6.2         ****Exchange Rate; Manner and Place ofPayment. **All payments hereunder shall be payable in U.S.dollars.  When conversion of paymentsfrom any foreign currency is required, such conversion shall be at the averageof the rates of exchange reported in *TheWall Street Journal*, Eastern U.S. Edition, for each business day ofthe applicable calendar quarter.  Allpayments owed under this Agreement shall be made by wire transfer inimmediately available funds to a bank and account designated in writing byMetabasis, unless otherwise specified in writing by Metabasis.

 

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**6.3         ****Income Tax Withholding. **Metabasis will pay any and all taxes levied on accountof any payments made to it under this Agreement.  If any taxes are required to be withheld byIdenix, Idenix will (a) deduct such taxes from the payment made toMetabasis, (b) timely pay the taxes to the proper taxing authority, and(c) send proof of payment to Metabasis and certify its receipt by thetaxing authority within [***] following such payment.

**6.4         ****Audits. **During the Term and for a period of [***] thereafter,Idenix shall keep complete and accurate records pertaining to the sale or otherdisposition of Products in sufficient detail to permit Metabasis to confirm theaccuracy of all royalties due hereunder and Idenix shall require itsSublicensees to provide such records to Idenix. Metabasis shall have the right not more than once a year to cause anindependent, certified public accountant reasonably acceptable to Idenix toaudit such records to confirm Net Sales, royalties and other payments for aperiod covering not more than the preceding [***].  Such audits may be exercised during normalbusiness hours upon reasonable prior written notice to Idenix.  Prompt adjustments shall be made by theParties to reflect the results of such audit. Metabasis shall bear the full cost of such audit unless such auditdiscloses an underpayment by Idenix of more than [***] of the amount ofroyalties or other payments due under this Agreement, in which case, Idenixshall [***] of such audit and shall promptly remit to Metabasis the amount ofany underpayment.

**6.5         ****Late Payments.** In the event that any payment due under this Agreement is not made whendue, the payment shall accrue interest from the date due at the rate of [***]; *provided, however*, that in no event shallsuch rate exceed the maximum legal annual interest rate.  The payment of such interest shall not limitMetabasis from exercising any other rights it may have as a consequence of thelateness of any payment.

**7.****                                     ****CONFIDENTIALITYAND PUBLICATION**

**7.1         ****Confidential Information. **Except to the extent expressly authorized by thisAgreement or otherwise agreed in writing by the Parties, the Parties agreethat, during the Term and for [***] thereafter, the receiving Party shall keepconfidential and shall not publish or otherwise disclose and shall not use forany purpose other than as expressly provided for in this Agreement anyInformation furnished to it by the other Party pursuant to this Agreement, oras provided below, owned by the other Party, and any Proprietary Information(as defined in the Confidentiality Agreement) furnished to it by the otherparty pursuant to the Confidentiality Agreement (collectively, ***“Confidential Information”***).  For the avoidance of doubt, and withoutlimiting the generality of the foregoing, Idenix Know-How is ConfidentialInformation of Idenix, Metabasis Know-How is Confidential Information ofMetabasis, and Collaboration Technology and Joint Technology shall be deemedConfidential Information of both Parties. Each Party may use Confidential Information of the other Party only aspermitted by this Agreement.  Each Partywill use at least the same standard of care, and in no event less than areasonable standard of care, as it uses to protect proprietary or confidentialinformation of its own to ensure that its employees, agents, consultants andother representatives do not disclose or make any unauthorized use of theConfidential Information.  Each Partywill promptly notify the other upon discovery of any unauthorized use ordisclosure of the Confidential Information.

 

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**7.2         ****Exceptions. **Confidential Information shall not include anyinformation which the receiving Party can prove by competent evidence:(a) is now, or hereafter becomes, through no act or failure to act on thepart of the receiving Party, generally known or available; (b) is known bythe receiving Party at the time of receiving such information, as evidenced bywritten documents or records; (c) is hereafter furnished to the receivingParty by a Third Party, as a matter of right and without restriction on disclosure;(d) is independently discovered or developed by the receiving Partywithout the use of Confidential Information belonging to the disclosing Party;or (e) is the subject of a written permission to disclose provided to thereceiving Party by the disclosing Party.

**7.3         ****Authorized Disclosure. **Each Party may disclose Confidential Informationbelonging to the other Party as expressly permitted by this Agreement or if andto the extent such disclosure is reasonably necessary in the followinginstances:

**(a)          **filing or prosecuting Patents as permitted by this Agreement (only withwritten permission of the other Party);

**(b)          **regulatory filings for Products such Party has a license or right todevelop hereunder;

**(c)          **prosecuting or defending litigation as permitted by this Agreement;

**(d)          **complying with applicable court orders or governmental regulations;

**(e)          **in the case of Idenix, conducting development and/or commercializationactivities in accordance with a license granted under Section 4.2(a);

**(f)           **disclosure to Affiliates, licensees, sublicensees, employees,consultants or agents of the receiving Party who have a need to know suchinformation in order for the receiving Party to exercise its rights or fulfillits obligations under this Agreement, provided, in each case, that any suchAffiliate, licensee, sublicensee, employee, consultant or agent agrees to bebound by similar terms of confidentiality and non-use comparable in scope tothose set forth in this Article 7; and

**(g)          **disclosure to Third Parties in connection with due diligence or similarinvestigations by such Third Parties, and disclosure to potential Third Partyinvestors in confidential financing documents, provided, in each case, that anysuch Third Party agrees to be bound by similar terms of confidentiality andnon-use comparable in scope to those set forth in this Article 7; andprovided further that Metabasis may not, without Idenix’ prior written consent(such consent not to be unreasonably withheld), disclose to any Third Partypharmaceutical or biotechnology company that is a competitor of Idenix in theField any data provided to Metabasis by Idenix with respect to theCollaboration Compounds, Development Candidates or Products.

Notwithstanding the foregoing, in the event a Party isrequired to make a disclosure of the other Party’s Confidential Informationpursuant to Section 7.3(b) through (d), it will, except whereimpracticable, give reasonable advance notice to the other Party of suchdisclosure and use efforts to secure confidential treatment of such informationat least as diligent as such Party

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would use to protect its own confidential information,but in no event less than reasonable efforts. In any event, each Party agrees to take all reasonable action to avoiddisclosure of the other Party’s Confidential Information hereunder.  The Parties will consult with each other onthe provisions of this Agreement to be redacted in any filings made by theParties with the Securities and Exchange Commission or as otherwise required bylaw.

**7.4         ****Publication. **The Parties acknowledge their mutual interest inpublishing the results of Product development efforts in order to obtainrecognition within the scientific and investment communities and agree thatclinical trial results regarding Products may be published via press releaseand at investor conferences and presented at appropriate scientific conferencesin a timely fashion.  Each Party alsorecognizes the mutual interest in obtaining valid patent protection and inprotecting business interests and trade secret information and, in particular,it is the intent of each Party to maintain the confidentiality of the otherParty’s Confidential Information included in any patent application until suchtime as such patent application has been published.  Accordingly, a Party shall have the right toreview and comment on any material proposed for disclosure or publication bythe other Party, such as by oral presentation, manuscript or abstract, whichutilizes data generated from the development, manufacture or commercializationof Development Candidates or Products and/or includes Confidential Informationof the other Party.  Before any suchmaterial is submitted for publication, the Party proposing publication shalldeliver a complete copy to the other Party at least [***] prior to submittingthe material to a publisher or initiating any other disclosure.  Such other Party shall review any suchmaterial and give its comments to the Party proposing publication within [***]after the delivery of such material to such other Party.  With respect to oral presentation materialsand abstracts, such other Party shall make reasonable efforts to expeditereview of such materials and abstracts, and shall return such items as soon as practicableto the Party proposing publication with appropriate comments, if any, but in noevent later than [***] from the date of delivery to the non-publishingParty.  The publishing Party shall complywith the other Party’s request to delete references to the other Party’sConfidential Information in any such material and agrees to delay anysubmission for publication or other public disclosure for a period of up to anadditional [***] for the purpose of preparing and filing appropriate patentapplications.

**7.5         ****Publicity. **Each Party acknowledges and agrees that the otherParty intends, and shall be entitled, to****issuea press release announcing that the Parties have entered into this Agreementon, or as soon as practicable following, the Effective Date.  It is understood that each Party may desireor be required to issue subsequent press releases or make disclosures (pursuantto filings with the Securities and Exchange Commission or otherwise) relatingto the Agreement or activities thereunder. The Parties agree to consult with each other reasonably and in goodfaith with respect to the text and timing of all such press releases or otherdisclosures prior to the issuance thereof, provided that a Party may notunreasonably withhold consent to such releases or disclosures, and that eitherParty may issue such press releases or make such disclosures as it determines,based on advice of counsel, are reasonably necessary to comply with laws orregulations or for appropriate market disclosure.  In addition, following the initial pressreleases announcing this Agreement, either Party shall be free to disclose,without the other Party’s prior written consent, the existence of thisAgreement, the identity of the other Party and those terms of the Agreementwhich have already been publicly disclosed in accordance herewith.

 

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**8.****                                     ****REPRESENTATIONSAND WARRANTIES; LIMITATIONS OF LIABILITY**

**8.1         ****Mutual Representations andWarranties. **Each Party represents and warrants to theother that: (a) it is duly organized and validly existing under the lawsof its jurisdiction of incorporation and has full corporate or other power andauthority to enter into this Agreement and to carry out the provisions hereof;(b) it is duly authorized to execute and deliver this Agreement and to performits obligations hereunder, and the person or persons executing this Agreementon its behalf has been duly authorized to do so by all requisite corporateaction; (c) this Agreement is legally binding upon it, enforceable inaccordance with its terms, except as enforcement may be limited by (i)applicable bankruptcy or other laws affecting creditors generally or (ii)equitable principles including the availability of specific performance orinjunctive relief; and (d) this Agreement, and such Party’s performance of itsobligations hereunder, does not conflict with any material agreement,instrument or understanding, oral or written, to which it is a party or bywhich it may be bound, nor violate any law or regulation of any court,governmental body or administrative or other agency having jurisdiction overit.

**8.2         ****Metabasis Representations, Warrantiesand Covenants.**  Metabasis represents, warrants and covenantsto Idenix that:

**(a)          **as of the Effective Date, Metabasis Controls the Metabasis CorePatents;

**(b)          **as of the Effective Date, there are no pending legal actions of whichMetabasis has received written notice with respect to Metabasis Technology, andMetabasis has not received written notice of any pending or threatened claimsor litigation seeking to invalidate any Metabasis Patents or claiming that thepractice of Metabasis Technology infringes the intellectual property rights ofany Third Party;

**(c)          **to Metabasis’ knowledge, as of the Effective Date, the use of MetabasisTechnology does not infringe any valid Third Party Patent rights;

**(d)          **Metabasis will not knowingly use any know-how that is not Controlled byMetabasis, other than Idenix Know-How, in the Research Program, and, toMetabasis’ knowledge, no use of any know-how that is not Controlled byMetabasis, other than Idenix Know-How, is necessary for the conduct ofthe Research Program;

**(e)          **as of the Effective Date, to Metabasis’ knowledge, the issued U.S.claims of Metabasis Patents covering the use of HepDirect Technology are validand enforceable; and

**(f)           **as of the Effective Date, Metabasis is not aware (without any specificinvestigation) of any issued Patents (other than those rights licensed or to belicensed to Idenix pursuant to Section 4.2(a)) to which Idenix would require alicense in order to practice the Metabasis Technology to develop, make, havemade, use, sell, have sold, offer for sale and import Development Candidatesand Products in the Field.

**8.3         ****Idenix Representations andWarranties.**  Idenix represents and warrants to Metabasisthat:

**(a)          **as of the Effective Date, Idenix Controls the Idenix Nucleosides;

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**(b)          **as of the Effective Date, there are no pending legal actions of whichIdenix has received written notice with respect to Idenix Technology, andIdenix has not received written notice of any pending or threatened claims orlitigation seeking to invalidate any Idenix Patents or claiming that thepractice of Idenix Technology infringes the intellectual property rights of anyThird Party;

**(c)          **to Idenix’s knowledge, as of the Effective Date, the use of IdenixTechnology does not infringe any valid Third Party Patent rights;

**(d)          **as of the Effective Date, to Idenix’s knowledge, issued U.S. claims ofIdenix Patents covering the use of Idenix Nucleosides are valid andenforceable; and

**(e)          **as of the Effective Date, Idenix is not aware (without any specificinvestigation) of any issued Patents (other than those rights licensed or to belicensed to Idenix pursuant to Section 4.2(a)) to which Idenix would require alicense in order to practice the Idenix Technology to develop, make, have made,use, sell, have sold, offer for sale and import Development Candidates andProducts in the Field.

**8.4         ****Disclaimer. **Except as expressly set forth herein, THE TECHNOLOGYAND INTELLECTUAL PROPERTY RIGHTS PROVIDED BY EACH PARTY HEREUNDER ARE PROVIDED “ASIS” AND EACH PARTY EXPRESSLY DISCLAIMS ANY AND ALL WARRANTIES OF ANY KIND,EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE WARRANTIES OF DESIGN,MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT OF THEINTELLECTUAL PROPERTY RIGHTS OF THIRD PARTIES, OR ARISING FROM A COURSE OFDEALING, USAGE OR TRADE PRACTICES, IN ALL CASES WITH RESPECT THERETO.  Without limiting the generality of theforegoing, each Party expressly does not warrant (a) the success of anystudy or test commenced under the Research Program or (b) the safety orusefulness for any purpose of the technology it provides hereunder.

**8.5         ****Limitation of Liability. **EXCEPT FOR LIABILITY FOR BREACH OF ARTICLE 7,NEITHER PARTY SHALL BE ENTITLED TO RECOVER FROM THE OTHER PARTY ANY SPECIAL,INCIDENTAL, CONSEQUENTIAL OR PUNITIVE DAMAGES IN CONNECTION WITH THIS AGREEMENTOR ANY LICENSE GRANTED HEREUNDER; *provided,however,* that this Section 8.5 shall not be construed to limiteither Party’s indemnification obligations under Article 11.

**9.****                                     ****INTELLECTUALPROPERTY**

**9.1         ****Ownership.**

**(a)          ****Inventions.**  Inventorshipof Inventions made pursuant to this Agreement shall be determined in accordancewith the rules of inventorship under United States patent laws.  Except as expressly set forth below, a Partyshall own all such Inventions invented solely by one (1) or more employees orcontractors of such Party, and the Parties shall jointly own all JointTechnology.  Notwithstanding theforegoing:

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**(i)           **All right, title and interest in and to any Inventionconceived solely by a Party (or on its behalf) or jointly by the Parties (or ontheir behalf) after the Effective Date that is Collaboration Technology shallbe jointly owned by Idenix and Metabasis. Each Party hereby assigns to the other a joint ownership interest in andto its interest in Collaboration Technology.

**(ii)          **Each Party agrees to fully cooperate with the otherParty in protecting, maintaining and defending Collaboration Patents and JointPatents.

Inventions assigned underthis Sections 9.1(a) are assigned only to the extent that such Inventions aredirected and specific to such Invention of the applicable section.

**(b)          ****Disclosure.**  Each Partyshall promptly disclose to the other inventions within Collaboration Technologyor Joint Technology made in connection with this Agreement.  Each Party shall promptly execute all papersand instruments, and/or require its employees or contractors to execute suchpapers and instruments, as applicable, so as to effectuate the ownership oftechnology set forth in Section 9.1(a)(i) and to enable the other Party toapply for and to prosecute Patents as contemplated by Section 9.2. Idenixshall promptly disclose any Process Chemistry Technology to Metabasis.

**(c)          ****Limitations.**  Subject to the terms of this Agreement,including, without limitation, the license grants set forth in Section 4.2 andthe negative covenants set forth in Section 4.6 and subject to the provisionsof Section 12.2 regarding assignment, each Party shall have (1) the rightto practice under, and sell, license or otherwise transfer to its Affiliates orany Third Party, its right in Collaboration Technology only with the priorwritten consent of the other Party, and (2) the right to practice under, andsell, license or otherwise transfer to its Affiliates or any Third Party, itsright in Joint Technology without the consent of, and without duty to accountto, the other Party.

**9.2         ****Patent Prosecution.**

**(a)          ****Idenix Patents.** Idenix shall have the sole right to control thepreparation, filing, prosecution and maintenance of Idenix Patents andother patents that cover technology and inventions owned solely by Idenix.

**(b)          ****Metabasis Patents.** Metabasis shall have the sole right to control thepreparation, filing, prosecution and maintenance of Metabasis Patents andother patents that cover technology and inventions owned solely Metabasis.

**(c)          ****Joint Patents.**

**(i)           ****PrimaryResponsibility.**  Idenix shall beprimarily responsible for the preparation, filing, prosecution and maintenanceof Joint Patents, using patent counsel reasonably acceptable to Metabasis.  Idenix shall consult with Metabasis as to thepreparation, filing, prosecution and maintenance of each Joint Patentreasonably prior to any deadline or action with the U.S. Patent & TrademarkOffice or any foreign patent office, and shall furnish to Metabasis copies ofall relevant documents reasonably in advance of such consultation; *provided, however*, that any patentsubmission (including the filing of patent applications) with

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respect to any Joint Patent, to theextent that it either distinguishes or could reasonably be expected todisparage any claimed subject matter of a Metabasis Core Patent, shall requireMetabasis’ prior written consent (such consent not to be unreasonably withheldand such consent to be negotiated in good faith with all due consideration toany deadlines) except as required by law. The Parties shall mutually agree which jurisdictions to make JointPatent filings in, how to prosecute Joint Patents in such jurisdictions, andhow to proceed in response to any request for, or filing or declaration of, anyinterference, opposition or reexamination relating to any Joint Patent.

**(ii)          ****Metabasis Option toProsecute and Maintain Joint Patents.**  Idenix shall give timely notice to Metabasis of anydecision not to file applications for, or to cease prosecution and/ormaintenance of, or not to continue to pay the expenses of prosecution and/ormaintenance of, any Joint Patents on a country-by-country and patent-by-patent basisand, in such case, shall permit Metabasis, at its sole discretion and expense,to file or to continue prosecution or maintenance of such Joint Patents, inwhich event Idenix shall execute such documents and perform such acts at itsexpense as may be reasonably necessary to effect an assignment of such JointPatents to Metabasis  in a timelymanner.  Notwithstanding the foregoing,any patent submission with respect to any Joint Patent, to the extent that itcould reasonably be expected to either distinguish or disparage any claimedsubject matter of an Idenix Core Patent, shall require Idenix’ prior writtenconsent (such consent not to be unreasonably withheld and such consent to benegotiated in good faith with all due consideration to any deadlines) except asrequired by law.

**(iii)        ****Limitation.** Neither Party shall file any Joint Patent that claims Idenix Know-How orMetabasis Know-How, except upon the other Party’s prior written consent.

**(d)          ****Collaboration Patents.**  Allpreparation, filing, prosecution and maintenance of Collaboration Patents shallbe governed by this Section 9.2(d).

**(i)           ****Joint Patent Counsel.** Idenix and Metabasis will select patent counsel mutually agreeable toboth Parties (***“JointPatent Counsel”***) to prepare, file, prosecute, and maintain theCollaboration Patents.  Idenix will havethe first right to control the preparation, prosecution and maintenance of theCollaboration Patents, with Metabasis having the right to review and comment ondrafts of patent submissions.  Idenix shall give full consideration to Metabasis’position on prosecution and will work closely with Metabasis counsel to achievethe best Patent coverage on Collaboration Technology without adverselyaffecting either Party’s interests; *provided,however*, that any patent submission (including the filing of patentapplications) with respect to any Collaboration Patent, to the extent that iteither distinguishes or could reasonably be expected to disparage any claimedsubject matter of a Metabasis Core Patent, shall require Metabasis’ priorwritten consent (such consent not to be unreasonably withheld and such consentto be negotiated in good faith with all due consideration to any deadlines)except as required by law. As used herein, “prosecution” shall includeinterferences, reexaminations, reissues, oppositions, and the like.

**(ii)          ****Option to Prosecute and MaintainCollaboration Patents.**  Idenix shall give timely noticeto Metabasis of any decision not to file applications for, or to ceaseprosecution and/or maintenance of, or not to continue to pay the expenses ofprosecution

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and/or maintenance of, any Collaboration Patents on acountry-by-country and Patent-by-Patent basis and, in such case, shall permitMetabasis, at its sole discretion and expense, to file or to continue prosecutionor maintenance of such Collaboration Patents, in which event Idenix shallexecute such documents and perform such acts at its expense as may bereasonably necessary to effect an assignment of such Collaboration Patents toMetabasis in a timely manner. Notwithstanding the foregoing, any patent submission (including the filing of patent applications)with respect to any Collaboration Patent, to the extent that it couldreasonably be expected to either distinguish or disparage any claimed subject matter of an Idenix Core Patent,shall require Idenix’ prior written consent (such consent not to beunreasonably withheld and such consent to be negotiated in good faith with alldue consideration to any deadlines) except as required by law. Any patents orpatent applications so assigned shall not be considered part of CollaborationTechnology and the claims of such Patents shall not be subject to the licenseprovisions of Section 4.2.

**(iii)        ****Interference, Opposition,Reexamination and Reissue.**  Idenix and Metabasisshall inform the other of any request for, or filing or declaration of, anyinterference, opposition, or reexamination relating to the CollaborationPatents within [***] after learning of such event.  Idenix shall be the lead Party in any such interference,opposition, or reexamination relating to the Collaboration Patents, subject tothe provisions of this Section 9.2(d)(iii).  Metabasis shall have the right to review andconsult with Idenix regarding any submission to be made in connection with suchproceeding.  Notwithstanding theforegoing or any other provision of this Agreement to the contrary:

**(1)          **In any interference, opposition, or reexaminationrelating to any Collaboration Patent, Idenix shall not (and it will directJoint Patent Counsel and its witnesses and experts not to) distinguish ordisparage any * *claimed subject matter of aMetabasis Core Patent, without Metabasis’ prior written consent (such consentnot to be unreasonably withheld and such consent to be negotiated in good faithwith all due consideration to any deadlines) except as required by law;

**(2)          **Idenix shall give Metabasis timely notice of anyproposed settlement of an interference relating to a Collaboration Patent andshall not enter into such settlement without Metabasis’ prior written consent(such consent not to be unreasonably withheld);

**(3)          **Idenix shall give Metabasis timely notice of anydecision not to initiate or continue an interference relating to aCollaboration Patent, and in such case, so long as such interference does notinvolve a Collaboration Patent that claims the composition or method ofmanufacture or use of a Development Candidate or Product then under developmentor commercialization by Idenix, shall permit Metabasis, at its sole discretionand expense, to initiate or continue such interference in Metabasis’ name; inany interference, opposition, or reexamination relating to any CollaborationPatent, Metabasis shall not (and it will direct Joint Patent Counsel and itswitnesses and experts not to) distinguish or disparage any claimed subjectmatter of an Idenix Core Patent without Idenix’ prior written consent (suchconsent not to be unreasonably withheld and such consent to be negotiated ingood faith with all due consideration to any deadlines) except as required bylaw; and

 

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**(4)          **In connection with any interference, opposition,reissue or reexamination proceeding relating to the Collaboration Patents,Idenix and Metabasis will cooperate fully and will provide each other with anyinformation or assistance that either reasonably requests.  Each Party shall keep the other informed ofdevelopments in any such action or proceeding, including, to the extentpermissible by law, consultation and approval of any settlement.

**(iv)         ****Limitation.** Notwithstanding the foregoing provisions of this Section 9.2(d),neither Party shall file any Collaboration Patent that claims Idenix Know-Howor Metabasis Know-How, except upon the other Party’s prior written consent.

**(e)          ****Patent Fees.**

**(i)           **All costs associated with filing, prosecuting, issuingand maintaining Idenix Patents and other Patents described inSection 9.2(a), including interference, opposition, reexamination andreissue actions, shall be borne by Idenix.

**(ii)          **All costs associated with filing, prosecuting, issuingand maintaining Metabasis Patents and other Patents described inSection 9.2(b), including interference, opposition, reexamination andreissue actions, shall be borne by Metabasis.

**(iii)        **All costs associated with filing, prosecuting, issuingand maintaining Joint Patents, including interference, opposition,reexamination and reissue actions, shall be [***].

**(iv)         **All costs associated with filing, prosecuting, issuingand maintaining Collaboration Patents, including interference, opposition,reexamination and reissue actions within, [***].

**(f)           ****Cooperation Regarding Patents Claiming DifferentInventions.**  The Parties understand that certain Patentsfiled by the Parties after the Effective Date may claim different types ofInventions made pursuant to this Agreement, and this Section 9.2(f)describes how the Parties will address that situation.

**(i)           **In the event that a particular Patent filed after theEffective Date (provided that it is not the same disclosure of a Patent filedprior to the Effective Date, such as a renewal, division, continuation (inwhole), or request for continued examination (RCE), reissue, reexamination andthe like, which will remain subject to Section 9.2(a) or (b), asapplicable) includes both claims directed to Collaboration Know-How and claimsdirected to Idenix Know-How, a Joint Invention, Metabasis Know-How and/or otherInvention described in Section 9.2(a) or (b), the Parties will, ifrequested by either Party, work in good faith to separate such claims intoseparate Patent filings if feasible.  Ifthe Parties are legally unable to separate, or agree not to separate, suchclaims, then the applicable Patent shall be treated as a Collaboration Patentfor purposes of this Section 9.2. Each Party will promptly provide to the other Party informationreasonably requested by other Party that is necessary for the prosecutionactivities pursuant to this Section 9.2 with respect to such Patent.

 

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**(ii)          **In the event that a particular Patent filed after theEffective Date (provided that it is not the same disclosure of a Patent filedprior to the Effective Date, such as a renewal, division, continuation (inwhole), or request for continued examination (RCE), reissue, reexamination andthe like, which will remain subject to Section 9.2(a) or (b), asapplicable) includes both claims directed to a Joint Invention and claimsdirected to Idenix Know-How, Metabasis Know-How and/or other Inventiondescribed in Section 9.2(a) or (b), the Parties will, if requested byeither Party, work in good faith to separate such claims into separate Patentfilings if feasible.  If the Parties arelegally unable to separate, or agree not to separate, such claims, then theapplicable Patent shall be treated as (A) a Patent Controlled by Metabasisunder Section 9.2(b) if it includes both claims directed to a JointInvention and claims directed to Metabasis Know-How and/or otherInvention described in Section 9.2(b), or (B) Controlled by Idenixunder Section 9.2(a) if it includes both claims directed to a JointInvention and claims directed to Idenix Know-How and/or other Inventiondescribed in Section 9.2(a), for purposes of this Article 9.  If the applicable Patent is treated as aPatent Controlled by Metabasis under Section 9.2(b), and Metabasisdetermines to cease prosecution and or maintenance of, or not to continue topay the expenses of prosecution and/or maintenance of, such Patent on a country-by-countrybasis, Idenix may, at its sole discretion,continue prosecution or maintenance of such Patent to the extent directed  to Joint Inventions claimed therein and suchPatent shall then be treated as a Joint Patent. If the applicable Patent is treated as a Patent Controlled byIdenix under Section 9.2(a), and Idenix determines to cease prosecutionand or maintenance of, or not to continue to pay the expenses of prosecutionand/or maintenance of, such Patent on a country-by-country basis, Metabasis may, at its sole discretion, continueprosecution or maintenance of such Patent to the extent directed  to Joint Inventions claimed therein and suchPatent shall then be treated as a Joint Patent. Each Party will promptly provide to the other Party informationreasonably requested by other Party that is necessary for the prosecutionactivities pursuant to this Section 9.2 with respect to such Patent.

**(iii)        **In the event that a particular Patent filed after theEffective Date (provided that it is not the same disclosure of a Patent filedprior to the Effective Date, such as a renewal, division, continuation (inwhole), or request for continued examination (RCE), reissue, reexamination andthe like, which will remain subject to Section 9.2(a) or (b), asapplicable) includes both claims directed to Metabasis Know-How and/orother Invention described in Section 9.2(b) and claims directed to IdenixKnow-How and/or other Invention described in Section 9.2(a), the Partieswill, if requested by either Party, work in good faith to separate such claimsinto separate Patent filings if feasible. If the Parties are legally unable to separate, or agree not to separate,such claims, then the applicable Patent shall be treated as a Patent Controlledby Idenix under Section 9.2(a) for purposes of this Article 9.  Each Party will promptly provide to the otherParty information reasonably requested by other Party that is necessary for theprosecution activities pursuant to this Section 9.2 with respect to suchPatent

**(iv)         **The provisions for handling of patent applications inthis Section 9.2(f) do not affect ownership of claims, which is governed bySection 9.1.

**9.3         ****Enforcement and Defense.**

**(a)          **If either Party learns of any infringement of Idenix Patents or otherPatents described in Section 9.2(a), Metabasis Patents or other Patentsdescribed in Section 9.2(b), or

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Joint Patents, orany misappropriation or misuse of Idenix Know-How, Metabasis Know-How or JointInventions, such Party shall promptly notify the other Party of suchinfringement, misappropriation or misuse. Idenix shall have the sole right to initiate and prosecute any legalaction to enforce Idenix Technology and other Patents described inSection 9.2(a), at its own expense and in the name of Idenix, to retainany recovery obtained by it as a result of such legal action or settlementthereof, and to control the defense of any declaratory judgment or comparableaction relating to Idenix Technology or Patents described inSection 9.2(a) and to retain any recovery obtained by it as a result ofsuch action or settlement thereof.  Metabasisshall have the sole right to initiate and prosecute any legal action to enforceMetabasis Technology and other Patents described in Section 9.2(b), at itsown expense and in the name of Metabasis, to retain any recovery obtained by itas a result of such legal action or settlement thereof, and to control thedefense of any declaratory judgment or comparable action relating to MetabasisTechnology or Patents described in Section 9.2(b) and to retain anyrecovery obtained by it as a result of such action or settlement thereof.  Except as otherwise mutually agreed by theParties on a case-by-case basis, Idenix shallhave the first right to initiate and prosecute any legal action to enforceJoint Technology, at its own expense and in the name of Idenix, and, ifnecessary, Metabasis, or to control the defense of any declaratoryjudgment or comparable action relating to JointTechnology. If, within [***] following a request by Metabasis to Idenix toinitiate and prosecute such legal action or [***] before the time limit, ifany, set forth in the appropriate laws and regulations for the filing of suchactions, whichever comes first, Idenix fails to take such action, or if Idenixinforms Metabasis that it elects not to exercise such first right, Metabasis(or its designee) thereafter shall have the right either to initiate andprosecute such action or to control the defense of such declaratoryjudgment or comparable action in the name ofMetabasis and, if necessary, Idenix, at Metabasis’ expense.  Except as otherwise agreed by theParties as part of a cost-sharing arrangement, any recovery obtained by eitheror both Idenix and Metabasis in connection with or as a result of any action toenforce Joint Technology, whether by settlement or otherwise, shall first be appliedto reimburse the costs and expenses of the Party that brought and controlledsuch action and then to reimburse the costs and expenses of the other Party inconnection with such action, and any amounts remaining after such reimbursementshall be [***].  Neither Party shallsettle any action regarding Joint Technology without the prior written consentof the other Party (which shall not be unreasonably withheld).

**(b)          **If either Party learns of any infringement of Collaboration Patents, orany misappropriation or misuse of Collaboration Know-How, such Party shallpromptly notify the other Party of such infringement, misappropriation ormisuse.  Idenix and Metabasis thereaftershall promptly consult and cooperate fully to determine a course of action, including,without limitation, the commencement of legal action by either or both ofMetabasis and Idenix, to terminate any infringement of such CollaborationPatent or any misappropriation or misuse of Collaboration Know-How.  Idenix shall have the first right to initiateand prosecute such legal action at its own expense and in the name of Idenixand, if necessary, Metabasis, or to control the defense of any declaratoryjudgment or comparable action relating to Collaboration Patents orCollaboration Know-How. Metabasis’ shall pay its own attorneys fees and costsassociated with such action.  If, within[***] following a written request by Metabasis to Idenix to initiate andprosecute such legal action or [***] beforethe time limit, if any, set forth in the appropriate laws and regulations forthe filing of such actions, whichever comes first, Idenix fails to takesuch action, or if Idenix informs Metabasis that it elects not to exercise suchfirst

 

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right, Metabasis(or its designee) thereafter shall have the right either to initiate andprosecute such action or to control the defense of such  action in the name of Metabasis and, ifnecessary, Idenix. If Idenix elects not to initiate and prosecute aninfringement action as provided in this Section 9.3(b), and Metabasiselects to do so, the costs incurred by Metabasis in such course of action,including the costs of any legal action commenced or the defense of any  judgment, shall be borne solely by Metabasis.

**(c)          **In any infringement action relating to any Collaboration Patent orJoint Patent, Idenix shall not (and it will direct its attorneys, witnesses andexperts not to) distinguish or disparage any claimed subject matter of aMetabasis Core Patent, without Metabasis’ prior written consent (such consentnot to be unreasonably withheld and such consent to be negotiated in good faithwith all due consideration to any deadlines), except as required by law.

**(d)          **In any infringement action relating to any Collaboration Patent or JointPatent, Metabasis shall not (and it will direct its attorneys, witnesses andexperts not to) distinguish or disparage any claimed subject matter of anIdenix Core Patent without Idenix’ prior written consent (such consent not tobe unreasonably withheld and such consent to be negotiated in good faith withall due consideration to any deadlines), except as required by law.

**(e)          **For any action to terminate any infringement of Collaboration or JointPatents or any misappropriation or misuse of Collaboration or Joint Know-How,if either Party is unable to initiate or prosecute such action solely in itsown name, the other Party shall join such action voluntarily and shall executeall documents necessary to initiate litigation to prosecute and maintain such action.  In connection with any such action, Idenixand Metabasis shall cooperate fully and will provide each other with anyinformation or assistance that either reasonably requests.  Each Party shall keep the other informed ofdevelopments in any such action or proceeding, including, to the extentpermissible by law, the consultation and approval of any offer related thereto.

**(f)           **Except as otherwise agreed by the Parties as part of a cost-sharingarrangement, any recovery obtained by either or both Idenix and Metabasis inconnection with or as a result of any action contemplated bySections 9.3(b) through 9.3(e), whether by settlement or otherwise, shallbe shared in order as follows:

**(i)           **The Party which initiated and prosecuted the actionshall recoup all of its costs and expenses incurred in connection with theaction;

**(ii)          **The other Party shall then, to the extent possible,recover its costs and expenses incurred in connection with the action;

**(iii)        **Any remaining amounts after such reimbursement of theParties costs and expenses shall be retained by the Party that initiated andprosecuted the action; [***].

**(g)          **Each Party shall inform the other Party of any certification regardingany Collaboration Patents or Joint Patents it has received pursuant to either21 U.S.C. §§ 355(b)(2)(A)(iv) or (j)(2)(A)(vii)(IV) or its successorprovisions, or Canada’s Patented

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Medicines (Noticeof Compliance) Regulations Article 5, or any similar provisions in acountry other than the United States and Canada, and shall provide the otherParty with a copy of such certification within [***] of receipt by suchParty.  Metabasis’ and Idenix’s rightswith respect to the initiation and prosecution of any legal action as a resultof such certification or any recovery obtained as a result of such legal actionshall be as defined in Sections 9.3(b) through 9.3(f).

**(h)          **For any action under Section 9.3(b) through (e), the Party that iscontrolling such action shall continue to consult with the other Party on allmajor strategy decisions.

**(i)           **For any action under Section 9.3(b) through (e), the Party that iscontrolling such action shall give the other Party timely written notice of theproposed settlement of any such action, shall take full consideration of itsviews and shall not enter into any such settlement without the prior writtenconsent of such other Party, not to be unreasonably withheld.

**9.4         ****Limitation of Obligation.** For the sake of clarity, neither Party shallhave any limitation with regard to preparation, filing, prosecution,maintenance, interference, opposition, reexamination or infringement action ofany Patent controlled by such Party, except as expressly provided in thisArticle 9.

**9.5         ****Patent Term Restoration.** The Parties shall cooperate in obtaining patent term restoration orsupplemental protection certificates or their equivalents in any country whereapplicable to Collaboration Patents.  Ifelections with respect to obtaining such patent term restoration for aCollaboration Patent are to be made, Idenix shall have the right to make theelection to seek patent term restoration or supplemental protection andMetabasis shall abide by such election. For the purposes of clarity, the decision of whether to seek patent termrestoration or supplemental protection for any Metabasis Patent, regardless ofwhether the claims cover a Collaboration Compound, shall be made solely byMetabasis at Metabasis’ sole discretion. For the purposes of clarity, the decision of whether to seek patent termrestoration or supplemental protection for any Idenix Patent, regardless ofwhether the claims cover a Collaboration Compound, shall be made solely byIdenix at Idenix’ sole discretion.

**9.6         ****Infringement of Third PartyRights. **Each Party shall promptly notify the other in writingof any allegation by a Third Party that the activity of either of the Partiespursuant to this Agreement infringes or may infringe the intellectual propertyrights of such Third Party.  Idenix shallhave the sole right to control any defense of any such claim involving allegedinfringement of Third Party rights by Idenix’s activities at its own expenseand by counsel of its own choice, and Metabasis shall have the right, at itsown expense, to be represented in any such action by counsel of its ownchoice.  Metabasis shall have the soleright to control any defense of any such claim involving alleged infringementof Third Party rights by Metabasis’ activities at its own expense and bycounsel of its own choice, and Idenix shall have the right, at its own expense,to be represented in any such action by counsel of its own choice.

 

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**10.****                              ****TERM;TERMINATION**

**10.1       ****Term. **The term of the Research Program shall commence on theEffective Date and continue until expiration of the Research Term, unless thisAgreement is earlier terminated pursuant to Section 10.2 or 10.3.  The term of this Agreement (the ***“Term”***) shallcommence on the Effective Date and continue until the expiration of the lastRoyalty Term for any Product with respect to which Idenix has a license underthis Agreement, unless earlier terminated pursuant to Section 10.2 or10.3; *provided, however,* that[***], then this Agreement shall expire at such time.  Upon expiration (but not early termination)of the Royalty Term, on a Product-by-Product and country-by-country basis, thelicenses granted by Metabasis to Idenix under Section 4.2(a) with respect tosuch Product and country shall remain in effect on a perpetual, non-exclusive,sublicenseable and royalty-free basis; *provided,however,* that if Idenix does not make any payment owed pursuant toSection 5 with respect to such Product and country within the time relevanttimeframe for such payment, then such license shall lapse until such payment ismade.

**10.2       ****Termination for Cause. **Each Party shall have the right to terminate theResearch Program and/or this Agreement upon [***] prior written notice to theother upon the occurrence of any of the following:

**(a)          **Upon or after the bankruptcy, insolvency, dissolution or winding up ofthe other Party (other than a dissolution or winding up for the purpose ofreconstruction or amalgamation); or

**(b)          **Upon or after the breach of any material provision of this Agreement bythe other Party if the breaching Party has not cured such breach within the[***] following written notice of termination by the non-breaching Party.

**10.3       ****Termination by Idenix.** Idenix shall have the right to terminate this Agreement for any reasonor for no reason at any time after the expiration of the Research Term, orafter termination of the Research Term pursuant to Section 3.6(b), upon [***]prior written notice to Metabasis.

**10.4        Effectof Termination or Expiration; Surviving Obligations.**

**(a)          **Upon termination of this Agreement by Idenix pursuant toSection 10.2:

**(i)           **the license granted under Sections 4.2(b)(i), ifthen in effect, shall automatically terminate and revert to Idenix; and

**(ii)          **the licenses granted by Metabasis to Idenix underSection 4.2(a) shall remain in effect in accordance with their respectiveterms, subject to compliance by Idenix with all applicable provisions of thisAgreement, including, without limitation, Sections 4.1, 4.3, 4.4, 4.5,4.6, 5.4, 5.5 and 6.

**(b)          **Upon termination of this Agreement (i) by Idenix pursuant toSection 10.3, (ii) termination of this Agreement by Metabasis pursuant toSection 10.2 or (iii) pursuant to Section 4.4(c) with respect to one ormore but not all Major Markets, the licenses

 

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granted underSections 4.2(a) and (b)(i), if then in effect, shall automaticallyterminate and revert to the granting Party; which termination shall be worldwide,with respect to terminations described in clause (i) or (ii), and in therelevant Major Market(s), with respect to a termination described in clause(iii).

**(c)          **Effective upon termination of this Agreement (i) by Idenix pursuant toSection 10.3 for any reason [***], (ii) by Metabasis pursuant toSection 10.2 or (iii) pursuant to Section 4.4(c) with respect to one ormore but not all Major Markets, [***], Idenix shall, and it hereby does, grantto Metabasis an [***], to develop, make, have made, use, sell, offer for sale,have sold and import [***], and Idenix shall assign to Metabasis all of itsright, title and interest in and to all clinical, technical and other relevantreports, records, data, information and materials, regulatory filings andRegulatory Approvals with respect to the Development Candidates and Products inthe Field with respect to the relevant countries and Idenix shall deliver toMetabasis [***] of each physical embodiment of the aforementioned items within[***] after such termination and sell to Metabasis any then existing inventoryof Development Candidates and Products at Idenix’ cost.

**(d)          **Expiration or termination of this Agreement shall not relieve theParties of any obligation accruing prior to such expiration ortermination.  Except as set forth belowor elsewhere in this Agreement, the obligations and rights of the Parties underthe following provisions of this Agreement shall survive expiration ortermination of this Agreement:

Section 3.8 —Materials Transfer (last sentence only)

Section 4.2(b)(ii).

Section 4.6 — NegativeCovenants; No Implied Licenses

Section 6.4 — Audits

Section 6.5 — LatePayments

Section 7.1 —Confidential Information

 

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Section 7.2 —Exceptions

Section 7.3 —Authorized Disclosure

Section 7.4 —Publications

Section 8.4 —Disclaimer

Section 8.5 —Limitation of Liability

Section 9.1 —Ownership

Section 9.2 — PatentProsecution (for so long as (a) Idenix retains a license from Metabasis or (b)if applicable, Metabasis retains a license from Idenix, as contemplated bySection 10.4, with the rights and obligations of the Parties with respectto the prosecution of the Collaboration Patents and Joint Patents switched)

Section 9.3 —Enforcement and Defense (for so long as (a) Idenix retains a license fromMetabasis or (b) if applicable, Metabasis retains a license from Idenix, ascontemplated by Section 10.4, with the rights and obligations of theParties with respect to the enforcement and defense of the CollaborationPatents and Joint Patents switched)

Section 9.4 —Limitationof Obligation

Section 9.5 — PatentTerm Restoration (for so long as Idenix retains a license from Metabasis or, ifapplicable, Metabasis retains a license from Idenix, as contemplated bySection 10.4)

Section 9.6 —Infringement of Third Party Rights (for so long as (a) Idenix retains a licensefrom Metabasis or (b) if applicable, Metabasis retains a license from Idenix,as contemplated by Section 10.4, with the rights and obligations of theParties switched)

Section 10.4 —Effect of Termination or Expiration; Surviving Obligations

Section 10.5 —Exercise of Right to Terminate

Section 10.6 —Damages; Relief

Section 10.7 —Rights in Bankruptcy (for so long as (a) Idenix retains a license fromMetabasis or (b) if applicable, Metabasis retains a license from Idenix, ascontemplated by Section 10.4)

Article 11 —Indemnification

Article 12 —Miscellaneous

**(e)          **Within [***] following the expiration or termination of this Agreement,except to the extent and for so long as a Party retains license rights underSections 10.4(a) or (c), each Party shall deliver to the other Party anyand all Confidential Information of the other Party in its possession.

**10.5       ****Exercise of Right to Terminate. **The exercise by either Party of a termination rightprovided for under this Agreement shall not give rise to the payment of damagesor any other form of compensation or relief to the other Party with respectthereto, unless the termination itself is a breach of contract.

**10.6       ****Damages; Relief.  **Subject to Section 10.5 above, termination ofthis Agreement shall not preclude either Party from claiming any other damages,compensation or relief that it may be entitled to upon such termination.

**10.7       ****Rights in Bankruptcy. **The Parties agree that in the event a Party becomes adebtor under Title 11 of the U.S. Code (***“Title 11”***), this Agreement shall be deemedto be, for purposes of Section 365(n) of Title 11, a license to rights to “intellectualproperty” as defined

 

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therein.  Each Party as alicensee hereunder shall have the rights and elections as specified inTitle 11.  Any agreementssupplemental hereto shall be deemed to be “agreements supplementary to” thisAgreement for purposes of Section 365(n) of Title 11.

**11.****                              ****INDEMNIFICATION**

**11.1       ****Indemnification by Idenix. **Idenix hereby agrees to save, defend and holdMetabasis and its Affiliates and their respective directors, officers,employees and agents (each, a ***“Metabasis Indemnitee”***) harmless from and against anyand all claims, suits, actions, demands, liabilities, expenses and/or loss,including reasonable legal expense and attorneys’ fees (collectively, ***“Losses”***), to whichany Metabasis Indemnitee may become subject as a result of any claim, demand,action or other proceeding by any person or entity other than a Party or itsAffiliates to the extent such Losses arise directly or indirectly out of:(i) the practice by Idenix or any Sublicensee of any license granted to ithereunder, (ii) the manufacture, use, handling, storage, sale or otherdisposition of any Development Candidate or Product by Idenix or anySublicensee, or (iii) the breach by Idenix of any warranty,representation, covenant or agreement made by Idenix in this Agreement; except,in each case, to the extent such Losses result from the negligence or willfulmisconduct of any Metabasis Indemnitee or the breach by Metabasis of anywarranty, representation, covenant or agreement made by Metabasis in thisAgreement.

**11.2       ****Indemnification by Metabasis. **Metabasis hereby agrees to save, defend and holdIdenix and its Affiliates and their respective directors, officers, employeesand agents (each, an ***“IdenixIndemnitee”***) harmless from and against any and all Losses towhich any Idenix Indemnitee may become subject as a result of any claim,demand, action or other proceeding by any person or entity other than a Partyor its Affiliates to the extent such Losses arise directly or indirectly outof: (i) the practice by Metabasis, its Affiliates or sublicensees (excludingIdenix and Sublicensees) of any license granted to it hereunder, (ii) themanufacture, use, handling, storage, sale or other disposition of any productby Metabasis, its Affiliates or sublicensees (excluding Idenix andSublicensees) pursuant to rights granted under this Agreement, or(iii) the breach by Metabasis of any warranty, representation, covenant oragreement made by Metabasis in this Agreement; except, in each case, to theextent such Losses result from the negligence or willful misconduct of anyIdenix Indemnitee or the breach by Idenix of any warranty, representation,covenant or agreement made by Idenix in this Agreement.

**11.3       ****Control of Defense.** Any entity entitled to indemnification under this Article 11 shallgive notice to the indemnifying Party of any Losses that may be subject toindemnification, promptly after learning of such Losses, and the indemnifyingParty shall assume the defense of such Losses with counsel reasonablysatisfactory to the indemnified Party. The failure of the indemnified Party to promptly give notice to theindemnifying Party shall, to the extent the indemnifying Party is actually andmaterially prejudiced by such delay, relieve the indemnifying Party of itsobligations to the extent of the harm suffered by such delay.  If such defense is assumed by theindemnifying Party with counsel so selected, the indemnifying Party will not besubject to any liability for any settlement of such Losses made by theindemnified Party without the indemnifying Party’s prior consent (but suchconsent will not be unreasonably withheld or delayed), and will not beobligated to pay the fees and expenses of any separate counsel retained by theindemnified Party with respect to such Losses. The indemnified Party shall provide the indemnifying Party with allinformation in its possession and all assistance reasonably necessary

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to enable the indemnifying Party to carry on thedefense of any such Losses.  Without theprior written consent of the other Party, neither the indemnified Party nor theindemnifying Party shall agree to any settlement that does not include acomplete release of such other Party from all liability with respect thereto orthat imposes any liability, obligation or restriction on such other Party.

**11.4       ****Insurance. **At their own expense, each Party shall maintainproduct liability insurance (or self-insure) in an amount consistent withindustry standards during the Term.

**12.****                              ****MISCELLANEOUS**

**12.1       ****Force Majeure. **Neither Party shall be held liable to the other Partynor be deemed to have defaulted under or breached this Agreement for failure ordelay in performing any obligation under this Agreement (other than failure tomake payment when due) when such failure or delay is caused by or results fromcauses beyond the reasonable control of the affected Party including, but notlimited to, embargoes, war, acts of war (whether war be declared or not),insurrections, riots, civil commotions, strikes, lockouts or other labordisturbances, fire, floods, or other acts of God, or acts, omissions or delaysin acting by any governmental authority or the other Party.  The affected Party shall notify the otherParty of such force majeure circumstances as soon as reasonably practical, andshall promptly undertake all reasonable efforts necessary to cure such forcemajeure circumstances.  Such excuse fromliability shall be effective only to the extent and duration of the event(s)causing the failure or delay in performance and provided that the Party has notcaused such event(s) to occur.

**12.2       ****Assignment. **Except as expressly provided hereunder, neither thisAgreement nor any rights or obligations hereunder may be assigned or otherwisetransferred by either Party without the prior written consent of the otherParty (which consent shall not be unreasonably withheld); *provided, however*, that either Party mayassign this Agreement and its rights and obligations hereunder without theother Party’s consent: (a) in connection with the transfer or sale of allor substantially all of the business of such Party to which this Agreementrelates to a Third Party, whether by merger, sale of stock, sale of assets orotherwise, provided that in the event of a transaction (whether this Agreementis actually assigned or is assumed by the acquiring Party by operation of law (*e.g.*, in the context of a reversetriangular merger)), intellectual property rights of the acquiring Party tosuch transaction (if other than one of the Parties to this Agreement) shall notbe included in the technology licensed hereunder; or (b) to an Affiliate,provided that (x) the assigning Party shall remain liable and responsible tothe non-assigning Party  for theperformance and observance of all such duties and obligations by such Affiliateand (y) the assignee shall assume the rights and obligations of the assigningParty under this Agreement in a signed, written document.  The rights and obligations of the Partiesunder this Agreement shall be binding upon and inure to the benefit of thesuccessors and permitted assigns of the Parties.  Any assignment not in accordance with thisAgreement shall be void.

**12.3       ****Severability **If any one or more of the provisions contained in thisAgreement is held invalid, illegal or unenforceable in any respect, thevalidity, legality and enforceability of the remaining provisions containedherein shall not in any way be affected or impaired thereby, unless the absenceof the invalidated provision(s) adversely affects the substantive rights of the

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Parties.  The Parties shall insuch an instance use their best efforts to replace the invalid, illegal orunenforceable provision(s) with valid, legal and enforceable provision(s)which, insofar as practical, implement the purposes of this Agreement.

**12.4       ****Notices. **All notices which are required or permitted hereundershall be in writing and sufficient if delivered personally, sent by facsimile(and promptly confirmed by personal delivery, registered or certified mail orovernight courier), sent by nationally-recognized overnight courier or sent byregistered or certified mail, postage prepaid, return receipt requested,addressed as follows:
|        | if to Metabasis, to: | Metabasis Therapeutics, Inc.11119 North Torrey Pines Road  La Jolla, CA 92037  Attention: Chief Executive Officer  Facsimile No.: (858) 587-2770 |   |
|--------|----------------------|--------------------------------------------------------------------------------------------------------------------------------------------------|--------|
|   |                 |
|   | if to Idenix, to:    | Idenix Pharmaceuticals, Inc.  60 Hampshire Street  Cambridge, MA 02139  Attention: Chief Executive Officer  Facsimile No.: (617) 995-9801        |   |
|   |                 |
|        |                      |                                                                                                                                                  |        |  |

orto such other address as the Party to whom notice is to be given may have furnishedto the other Party in writing in accordance herewith.  Any such notice shall be deemed to have beengiven: (a) when delivered if personally delivered or sent by facsimile on abusiness day; (b) on the business day after dispatch if sent by nationally-recognizedovernight courier; and/or (c) on the fifth business day following the date ofmailing if sent by mail.

**12.5       ****Applicable Law. **This Agreement shall be governed by and construed inaccordance with the laws of the State of New York, and the patent laws of theUnited States without reference to any rules of conflict of laws.  The United Nations Convention on the Sale ofGoods shall not apply.

**12.6       ****Dispute Resolution.**

**(a)          **The Parties shall negotiate in good faith and use reasonable efforts tosettle any dispute, controversy or claim arising from or related to thisAgreement or the breach thereof.  If theParties cannot resolve the dispute, controversy or claim (other than any suchmatter to be resolved by the Committee, which shall not be subject to thisSection 12.6 but shall be resolved solely pursuant to the procedures setforth in Section 2.4) within [***] after a written request by either Partyto the other Party, the Parties agree to hold a meeting, attended by the ChiefExecutive Officer of Metabasis and the Chief Executive Officer of Idenix (ortheir equivalents), as appropriate in light of the subject matter of thedispute, to attempt in good faith to negotiate a resolution of the disputeprior to pursuing other available remedies. If, within [***] after such written request, the Parties have notsucceeded in negotiating a resolution of the dispute, and a Party wishes topursue the matter, each such dispute, controversy

 

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or claim that isnot an Excluded Claim shall be resolved by binding arbitration in accordancewith the [***] as then in effect, and judgment on the arbitration award may beentered in any court having jurisdiction thereof.  The decision rendered in any such arbitrationwill be final and not appealable.  Ifeither Party intends to commence binding arbitration of such dispute,controversy or claim, such Party will provide written notice to the other Partyinforming the other Party of such intention and the issues to be resolved.  Within [***] after the receipt of suchnotice, the other Party may by written notice to the Party initiating bindingarbitration, add additional issues to be resolved.

**(b)          **The arbitration shall be conducted by a panel of three (3) personsexperienced in the pharmaceutical business, none of whom shall be a current orformer employee or director, or a then-current stockholder, of either Party,their respective Affiliates or any sublicensee of a Party.  Within [***] after receipt of the originalnotice of binding arbitration (the ***“Notice Date”***), each Party shall select one(1) person to act as arbitrator and the two (2) Party-selected arbitratorsshall select a third arbitrator within [***] of their appointment.  If the arbitrators selected by the Partiesare unable or fail to agree upon the third arbitrator, the third arbitratorshall be appointed by the [***].  Theplace of arbitration shall be [***] and all proceedings and communicationsshall be in English.

**(c)          **Within [***] after the designation of the arbitrators pursuant toSection 12.6(b) (the ***“ProposedResolution Deadline”***), each Party shall submit to thearbitrators and to the other Party a statement of all disputed issues and aproposed ruling on the merits of each such issue together with a brief or otherwritten memorandum supporting the merits of its resolution.

**(d)          **The arbitrators and the Parties shall then meet within [***] after theProposed Resolution Deadline, at which time each Party shall have [***] toargue in support of its proposed resolution. The Parties shall not call any witnesses in support of theirarguments.  The Parties shall have theright to be represented by counsel.

**(e)          **The arbitrators shall use their best efforts to rule on the disputewithin [***] thereafter.  The arbitratorsshall resolve the dispute by a vote of the majority of the arbitratorsselecting one of the two (2) proposed resolutions in its entirety, withoutsubstitution, deletion, addition or amendment. Such selected resolution shall be binding and conclusive upon theParties.  All rulings of the arbitratorsshall be in writing and shall be delivered to the Parties.

**(f)           **The arbitrators will, in rendering their decision, apply thesubstantive law of the State of New York, without giving effect to itsprinciples of conflicts of law, and without giving effect to any rules or lawsrelating to arbitration.

**(g)          **The arbitrators, in rendering their decision, shall not modify or amendthe terms and conditions of this Agreement or determine any issue in a mannerthat would conflict with the express terms and conditions of this Agreement.

 

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**(h)          **Either Party may apply to the arbitrators for interim injunctive reliefuntil the arbitration award is rendered or the controversy is otherwiseresolved.  Either Party also may, withoutwaiving any remedy under this Agreement, seek from any court havingjurisdiction any injunctive or provisional relief necessary to protect therights or property of that Party pending the arbitration award.  The arbitrators shall have no authority toaward punitive or any other non-compensatory damages, except as may be providedin Section 8.5.  The Party whoseproposed resolution was not selected by the majority vote of the arbitratorsshall pay the full costs of the arbitration and the reasonable costs andexpenses of the prevailing Party, including, without limitation, reasonableattorneys’ fees and travel and lodging costs.

**(i)           **Except to the extent necessary to confirm or enforce an award or as maybe required by law, neither a Party nor an arbitrator may disclose theexistence, content, or results of an arbitration without the prior writtenconsent of both Parties.  In no eventshall an arbitration be initiated after the date when commencement of a legalor equitable proceeding based on the dispute, controversy or claim would bebarred by the applicable New York statute of limitations.

**(j)           **As used in this Section, the term ***“Excluded Claim”*** shall mean a dispute,controversy or claim that concerns (i) the validity, enforceability or infringementof a patent, trademark or copyright; or (ii) any antitrust, anti-monopoly orcompetition law or regulation, whether or not statutory.

**(k)          **In no event shall an arbitration be initiated after the date whencommencement of a legal or equitable proceeding based on the dispute,controversy or claim would be barred by the applicable New York statute oflimitations.

**12.7       ****Entire Agreement; Amendments. **This Agreement, together with the letter agreementbetween the Parties dated as of the Effective Date regarding the Research Plan,contains the entire understanding of the Parties with respect to the subjectmatter hereof and thereof and supersedes and cancels all previous express orimplied agreements and understandings, negotiations, writings and commitments,either oral or written, in respect to the subject matter hereof and thereof,including, without limitation, the Confidentiality Agreement.  This Agreement and the Research Plan may beamended, or any term hereof modified, only by a written instrument dulyexecuted by authorized representatives of both Parties.

**12.8       ****Headings. **The captions to the several Articles and Sectionshereof are not a part of this Agreement, but are merely for convenience toassist in locating and reading the several Articles and Sections hereof.

**12.9       ****Independent Contractors. **It is expressly agreed that Metabasis and Idenix shallbe independent contractors and that the relationship between the two Partiesshall not constitute a partnership, joint venture or agency.  Neither Metabasis nor Idenix shall have theauthority to make any statements, representations or commitments of any kind,or to take any action, which shall be binding on the other Party, without theprior written consent of the other Party.

**12.10     ****Waiver. **The waiver by either Party of any right hereunder, orthe failure of the other Party to perform, or a breach by the other Party,shall not be deemed a waiver of any other

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right hereunder or of any other breach or failure bysuch other Party whether of a similar nature or otherwise.

**12.11     ****Cumulative Remedies. **No remedy referred to in this Agreement is intended tobe exclusive, but each shall be cumulative and in addition to any other remedyreferred to in this Agreement or otherwise available under law.

**12.12     ****Waiver of Rule of Construction. **Each Party has had the opportunity to consult withcounsel in connection with the review, drafting and negotiation of thisAgreement.  Accordingly, the rule ofconstruction that any ambiguity in this Agreement shall be construed againstthe drafting Party shall not apply.

**12.13     ****Counterparts. **This Agreement may be executed in multiplecounterparts, each of which shall be deemed an original, but all of whichtogether shall constitute one and the same instrument.

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**IN WITNESS WHEREOF,** theParties  have duly executed this **EXCLUSIVE LICENSE AND RESEARCHCOLLABORATION AGREEMENT** as of the Effective Date.
| **IDENIX PHARMACEUTICALS, INC.** | ** **                | **METABASIS THERAPEUTICS, INC.** |
|----------------------------------|---------------------------|----------------------------------|
| ** **                       | ** **                |                             |
| ** **                       | ** **                |                             |
| By:                              | /s/ Jean-Pierre Somadossi | ** **                       | By: | /s / Paul Laikind |
| Name:                            | Dr. Jean-Pierre Somadossi | ** **                       | Name: | Paul Laikind |   |
| Title:                           | Vice President            | ** **                       | Title: | President and CEO |   |
|                                  |                           |                                  |  |  |  |  |

 

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**EXHIBIT A**

IDENIX CORE PATENTS

| [***]      |
|------------|
| ** ** |

 

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A-1

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[***]

 

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A-2

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[***]
| [***] |
|-------|

 
| Country | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
|---------|------------|------------------|------------|---------------------|------------|----------------|
| [***]   |       |             |       |                |       |           |

 

***ConfidentialTreatment Requested

A-3

----

 
| [***] |
|-------|

 
| [***] |
|-------|

 
| Country | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
|---------|------------|------------------|------------|---------------------|------------|----------------|
| [***]   |       |             |       |                |       |           |

 

 

***ConfidentialTreatment Requested

A-4

----

[***]

 

***ConfidentialTreatment Requested

A-5

----

[***]
| [***] |
|-------|

 
| Country | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
|---------|------------|------------------|------------|---------------------|------------|----------------|
| [***]   |       |             |       |                |       |           |

 

***ConfidentialTreatment Requested

A-6

----

[***]

 

***ConfidentialTreatment Requested

A-7

----

[***]
| [***] |
|-------|

 
| Country | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
|---------|------------|------------------|------------|---------------------|------------|----------------|
| [***]   |       |             |       |                |       |           |

 

***ConfidentialTreatment Requested

A-8

----

[***]

***ConfidentialTreatment Requested

A-9

----

 
| [***] |
|-------|

 
| Country | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
|---------|------------|------------------|------------|---------------------|------------|----------------|
| [***]   |       |             |       |                |       |           |

 

***ConfidentialTreatment Requested

A-10

----

[***]

***ConfidentialTreatment Requested

A-11

----

 

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

 

***ConfidentialTreatment Requested

A-12

----

[***]

***ConfidentialTreatment Requested

A-13

----

 

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

 

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

 

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A-14

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[***]

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

 

***ConfidentialTreatment Requested

A-15

----

 

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

 

***ConfidentialTreatment Requested

A-16

----

 

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

 

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

 

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

 

***ConfidentialTreatment Requested

A-17

----

[***]

 

***ConfidentialTreatment Requested

A-18

----

[***]

| [***]       | ** ** | ** **       | ** ** | ** **               | ** ** | ** **          | ** ** |
|-------------|------------|------------------|------------|--------------------------|------------|---------------------|------------|
| **Country** | ** ** | **Filing  Date** | ** ** | **Application No.** | ** ** | **Patent No.** | ** ** |
| [***]       |       |             |       |                     |       |                |       |

                                              

***ConfidentialTreatment Requested

A-19

----

[***]

 

***ConfidentialTreatment Requested

 

A-20

----

**EXHIBIT B**

METABASIS CORE PATENTS

 
| **Exhibit B** |       |            |       |            |       |           |
|---------------|------------|-----------------|------------|-----------------|------------|----------------|
|          |       |            |       |            |       |           |
| [***]         |       |            |       |            |       |           |
|          |       |            |       |            |       |           |
|          |       |            |       |            |       |           |
| **Country**   | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
| [***]         |       |            |       |            |       |           |

 
| [***]       |       |            |       |            |       |           |
|-------------|------------|-----------------|------------|-----------------|------------|----------------|
|        |       |            |       |            |       |           |
|        |       |            |       |            |       |           |
| **Country** | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
| [***]       |       |            |       |            |       |           |

 

 

***Confidential TreatmentRequested

 

B-1

----

 

[***]

 

 

***ConfidentialTreatment Requested

B-2

----

 

| [***]  |   |   |   |   |   |   |
|--------|--------|--------|--------|--------|--------|--------|
|   |   |   |   |   |   |   |
| [***]  |   |   |   |   |   |   |

 

|             |
|-------------|
| **Country** | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
| [***]       |   |   |   |   |   |   |

 

 

***Confidential TreatmentRequested

B-3

----

EXHIBIT C

IDENIX PATENTS

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
|        |       |            |       |                |       |           |
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-1

----

[***]

 

***ConfidentialTreatment Requested

C-2

----

[***]

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
|        |       |            |       |                |       |           |
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-3

----

[***]

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
|        |       |            |       |                |       |           |
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-4

----

[***]

 

 

***ConfidentialTreatment Requested

C-5

----

[***]

 

| [***]       | ** ** | ** **      | ** ** | ** **          | ** ** | ** **     |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
|        | ** ** | ** **      | ** ** | ** **          | ** ** | ** **     |
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-6

----

[***]

 

 

***ConfidentialTreatment Requested

C-7

----

[***]

 

| **[***]**   | ** ** | ** **      | ** ** | ** **          | ** ** | ** **     |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| ** **  | ** ** | ** **      | ** ** | ** **          | ** ** | ** **     |
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-8

----

[***]

 

 

***ConfidentialTreatment Requested

C-9

----

[***]

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
|        |       |            |       |                |       |           |
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

| **[***]**   |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| ** **  |       |            |       |                |       |           |
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-10

----

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
|        |       |            |       |                |       |           |
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-11

----

[***]

 

 

***ConfidentialTreatment Requested

C-12

----

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-13

----

[***]

 

***ConfidentialTreatment Requested

C-14

----

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

***ConfidentialTreatment Requested

C-15

----

 

[***]

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-16

----

 

[***]

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-17

----

[***]

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

***ConfidentialTreatment Requested

C-18

----

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-19

----

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

| [***]       |       |            |       |                |       |           |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-20

----

[***]

| [***]       | ** ** | ** **      | ** ** | ** **          | ** ** | ** **     |
|-------------|------------|-----------------|------------|---------------------|------------|----------------|
| **Country** | ** ** | **Filing Date** | ** ** | **Application No.** | ** ** | **Patent No.** |
| [***]       |       |            |       |                |       |           |

 

 

***ConfidentialTreatment Requested

C-21

----

**EXHIBIT D**

METABASIS PATENTS

| Exhibit D  | ** ** | ** ** | ** ** | ** ** | ** ** | ** ** |
|------------|------------|------------|------------|------------|------------|------------|
| ** ** |       |       |       |       |       |       |
| [***]      |       |       |       |       |       |       |

 

| Country | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
|---------|------------|-----------------|------------|-----------------|------------|----------------|
| [***]   |       |            |       |            |       |           |
|    |       |            |       |            |       |           |
| [***]   |       |            |       |            |       |           |

 

| Country | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
|---------|------------|-----------------|------------|-----------------|------------|----------------|
| [***]   |       |            |       |            |       |           |

 

***ConfidentialTreatment Requested

D-1

----

 

[***]

 

***ConfidentialTreatment Requested

 

D-2

----

 

| [***]  |   |   |   |   |   |   |
|--------|--------|--------|--------|--------|--------|--------|
|   |   |   |   |   |   |   |

 

| Country | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
|---------|------------|-----------------|------------|-----------------|------------|----------------|
| [***]   |       |            |       |            |       |           |

 

| [***]  |   |   |   |   |   |   |
|--------|--------|--------|--------|--------|--------|--------|
|   |   |   |   |   |   |   |

 

| Country | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
|---------|------------|-----------------|------------|-----------------|------------|----------------|
| [***]   |       |            |       |            |       |           |

 

| [***]  |   |   |   |   |   |   |
|--------|--------|--------|--------|--------|--------|--------|
|   |   |   |   |   |   |   |

 

| Country | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
|---------|------------|-----------------|------------|-----------------|------------|----------------|
| [***]   |       |            |       |            |       |           |

 

***ConfidentialTreatment Requested

D-3

----

 

| [***]  |   |   |   |
|--------|--------|--------|--------|
|   |   |   |   |
| [***]  |   |   |   |

 

| Country | ** ** | **Applic. No.** | ** ** | **Filing Date** | ** ** | **Patent No.** |
|---------|------------|-----------------|------------|-----------------|------------|----------------|
| [***]   |       |            |       |            |       |           |

 

***ConfidentialTreatment Requested

D-4

----