Diapositive 1

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Table Ronde C.U.R.I.E. - RETIS Partie 2
Retours dexpériences MERCREDI 17 JUIN
Dr. Jean-Marc ALLAIRE, VP Europe Laboratoires
Idenix sarl Cap Gamma, Montpellier
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Safe Harbor

• This presentation includes forward-looking
  statements about Idenix and its business,
  including without limitation, statements
  regarding drug discovery, research and clinical
  development, regulatory approval processes and
  commercialization activities. These
  forward-looking statements are subject to risks
  and uncertainties that may cause actual events or
  results to differ materially from our current
  expectations. These risks and uncertainties are
  detailed in our filings with the Securities and
  Exchange Commission. All forward-looking
  statements speak only as of the date of this
  presentation and, except as required by law, we
  undertake no obligation to update such
  statements.

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Idenix - Building a Leading Antiviral Franchise
Mission
Discover and develop innovative antiviral drugs
addressing unmet medical needs in large and
growing markets
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Idenixs Global Structure
Idenix Pharmaceuticals Inc, Cambridge, MA
Laboratoires Idenix sarl Montpellier, Fr
RD France Italy
RD Cambridge, MA

• 170 Employees (55 in Montpellier)

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Idenix RD Structure and Organization

• In house Discovery
• Medicinal chemistry, nucleoside and heterocyclic
  analogues (EU)
• Anti-viral screening platform and mutated virus
  libraries (US, EU)
• MOA, molecular virology and pharmacology (US)
• External collaborations
• Academic medicinal chemistry teams, academic and
  private chemical libraries (EU, US)
• Pre-clinical development
• Full in-house IND and NDA pre-clinical dossier
  (US)
• Pharmaceutical development
• In house scale-up capabilities (US)
• Full in-house IND and NDA dossier (US)
• External collaboration for drug manufacturing and
  supply

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Idenix RD Structures and Organization

• Clinical development
• Full in-house clinical research expertise for
  antiviral clinical development in HCV, HIV (US,
  FR)
• In-house and subcontracted clinical operations
  world-wide (NA, EU, Asia)
• Regulatory affairs
• In-house world wide application with ICH common
  technical document expertise (US)

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Antiviral Drug Candidates with Best-in-Class
Potential
Tyzeka/Sebivo was co-developed by Idenix and
Novartis Pharma AG. Novartis has exclusive
worldwide commercialization rights to
Tyzeka/Sebivo. Idenix licensed its NNRTI
program, including IDX899, for the treatment of
HIV to GlaxoSmithKline in February 2009.
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Idenix Combination strategy
Comprehensive HCV Pipeline

• Nucleoside/tide Polymerase Inhibitor IDX184
• Potent antiviral activity in vitro and in vivo
• Liver-targeted with low systemic exposure
• Phase I/II in HCV-1 patients ongoing (QD)

• Protease inhibitor IDX316
• Single nanomolar potency
• Favorable early PK profile (BID, QD)
• IND planned for 2009

• Non-Nucleoside Polymerase Inhibitor IDX375
• Low nanomolar potency
• Favorable early PK profile (BID, QD)
• IND planned for 2009

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Idenix - Primary Objectives

• Solely focus the company on the discovery and
  development of direct-acting HCV antivirals
• Become the first biopharmaceutical company with
  direct-acting HCV antivirals in clinical
  development from three different drug classes
• Become the first biopharmaceutical company with a
  combination treatment of several direct-acting
  HCV antivirals