July 26, 2010

Gregg AltonExecutive Vice President

Corporate and Medical Affairs

AAAS Science and Human Rights Coalition

About Gilead Sciences

Worldwide presence

– 4,000 employees

– 25 offices on 4 continents

13 marketed drugs

– Primary therapeutic focus in HIV/AIDS, liver disease and serious cardiovascular and respiratory conditions

Eight successful acquisitions

– Expanding company’s therapeutic reach

Strong Geographical Presence

Australia

Ireland

U.K.

Portugal

Germany

Switzerland

Austria

ItalyGreece

TurkeyBranford, CT

San Dimas, CA

Foster City, CAPalo Alto, CA

Edmonton, Alberta

Seattle, WA

LEGEND

Research and Development Locations

Manufacturing Operations

China

France

Spain

Belgium

Sweden

Denmark

Norway

Finland

The Netherlands

Gilead Locations

New Zealand

Mississauga, ON

Durham, NC

Sales and Marketing Operations

Regional Partners to Support Registrations, Product Distribution and Medical Education

Aspen*Stendhal

Puerto RicoPharma

Delta

IDS

Anspec

Traphaco

Medicopharmacia

Nicholas Piramal

11 Distributors and 48 Sub-Distributors Reaching 130 Countries

Gador

Quadri

*Manufacturing and Distribution for Africa, in Africa

Our Therapeutic Areas

AtriplaAtriplaTruvadaTruvadaVireadViread

EmtrivaEmtrivaTruvada/rilpivirine FDR Truvada/rilpivirine FDR

(Ph III)(Ph III)Quad Quad (Ph III)(Ph III)

Elvitegravir Elvitegravir (Ph III)(Ph III)Cobicistat Cobicistat (Ph III)(Ph III)

Heart DiseaseHeart DiseaseRanexaRanexa

LexiscanLexiscanRegadenoson Regadenoson (filed (filed

with EMEA)with EMEA)Ranolazine Ranolazine (Ph II)(Ph II)

PAHPAHLetairisLetairis

Cicletanine Cicletanine (Ph II)(Ph II)

MetabolicMetabolicGS 9667 GS 9667 (Ph I)(Ph I)

InfluenzaInfluenzaTamifluTamiflu

CFCFCaystonCayston

Aztreonam Aztreonam (Ph III)(Ph III)

BronchiectasisBronchiectasisAztreonam Aztreonam (Ph II)(Ph II)

IPFIPFAmbrisentan Ambrisentan (Ph III)(Ph III)

PulmonaryPulmonary GS 6201 GS 6201 (Ph I)(Ph I)

HBVHBVHepseraHepseraVireadViread

HCVHCVGS 9190 GS 9190 (Ph II)(Ph II)

GS 9256/GS 9190 GS 9256/GS 9190 (Ph I)(Ph I)

NASHNASHGS 9450 GS 9450 (Ph II)(Ph II)

HIV/AIDSHIV/AIDS CardiovascularCardiovascular RespiratoryRespiratoryLiver DiseaseLiver Disease

Evolution of Fixed-Dose Combinations

Lamivudine (3TC; 1995)Lamivudine (3TC; 1995)

Zidovudine (AZT; 1987) Zidovudine (AZT; 1987) Combivir® (AZT/3TC;1997)Combivir® (AZT/3TC;1997) Trizivir® (ABC/AZT/3TC; 2000)Trizivir® (ABC/AZT/3TC; 2000)

Abacavir (ABC; 1998)Abacavir (ABC; 1998) Epzicom® (3TC/ABC; 2004)Epzicom® (3TC/ABC; 2004)

Tenofovir (TDF; 2001)Tenofovir (TDF; 2001) Truvada® (FTC/TDF; 2004)Truvada® (FTC/TDF; 2004) Atripla® (EFV/FTC/TDF; 2006)Atripla® (EFV/FTC/TDF; 2006)

Emtricitabine (FTC; 2003)Emtricitabine (FTC; 2003)

Efavirenz (EFV; 1998)Efavirenz (EFV; 1998)

GlaxoSmithKlineGlaxoSmithKline

Gilead / Bristol-Myers Squibb / MerckGilead / Bristol-Myers Squibb / Merck

2006: Single Tablet Regimen Approved

199630+ Pills a day

2006Introduction of Atripla®

HIV Pipeline – Addressing Unmet Needs

Truvada/rilpivirine fixed-dose regimen– Would be only second single-tablet regimen for HIV– Safer for use in pregnant women– Fewer CNS side effects

Cobicistat (novel PK enhancer) – No HIV activity – Good chemical stability (heat stable)– Enabling once-daily dosing of elvitegravir (integrase

inhibitor)– Broader role with protease inhibitors for tolerable and safe

combination therapy

HIV Research – New Targets

Active early-stage, preclinical research program identifying compounds that may inhibit HIV at newer targets in the virus’ life cycle– LEDGF Inhibitors

– Capsid Assembly Inhibitors

Exploring strategies and compounds to eradicate HIV in latently infected cells– Eliminate cells actively replicating HIV

– Infection by newly produced virus particles blocked by ARVs

D. D. Richman et al., Science 323, 1304 -1307 (2009)

Worldwide Impact of HIV/AIDS

DEVELOPING WORLD

~33 million infected

2.7 million new infections per year

Life expectancy in sub-Saharan Africa: 51

Without AIDS, life expectancy would be

62

UNITED STATES

~1 million infected

56,300 new infections per year

3 million years of human life saved

Life expectancy upon entering care:

24+

Gilead Access Program

Particular focus on countries hardest hit by the HIV/AIDS epidemic– 130 countries

– Including all of Africa

Pricing tiers– Based on a country’s economic

status and HIV prevalence

Support for:– Regional distributors

– Supply chain tools

– Medical education

– Product registrations

Access Initiatives – Generic Partnerships

Goal: Achieve the lowest pricefor least developed countries

Rationale: Indian manufacturershave proven track record in deliveringhigh volume/low margin qualityproducts

Parameters:– Full technology transfer to speed production and ensure quality– Develop any tenofovir-based FDC or pediatric formulation– Free to sell API within India with no royalty payment to Gilead– Free to set own price for finished product– Distribute within India and 94 other countries, pay 5% royalty to

Gilead– Seek WHO or tentative FDA approval

Expanding Access to HIV Treatment: Lower Prices, More Patients

$7.25

$8.25

$12.42

$12.00

$17.00702,911

31,000

508,103

129,279

$4

$6

$8

$10

$12

$14

$16

$18

2006 2007 2008 2009 2010

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

# pa

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Price

Patients

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Case Study: Matrix

55 Countries covered by Matrix – 58% of licensed territory

The Cost of Viread

U.S. W

AC

$21.43

~U.S.

Governm

ent

Mexic

o

Manufa

cturin

g Cost

$0.57

15% Dist. Margin

$1.00

Cost of manufacturing,

pre-distribution,

pharmacovigilance,

medical education

+ 5% royalty

Intellectual Property

Return on investment,

incentive for innovation

Canada

$17.13$4.00

LMI (

China, P

eru, T

hailand)

Brazil

$1.75

Access Pric

e

COST OF VIREAD TABLET (PER

DAY)

Model is Financially Self-Sustaining

FY 2009 FY 2008

Total Revenue

(in $,000)33,117 19,365

Total COGS

(in $,000)25,959 16,809

Operating Expenses

(in $,000)3,556 4,243

Total Contribution Margin

(in $,000)3,601 (1,688)

Total Contribution Margin

(as % of Total Revenue)10.9% -8.7%

Full Year 2010 GuidanceFull Year 2010 Guidance

* Non-GAAP product gross margin and expenses are non-GAAP and exclude the impact of acquisition, restructuring and stock-based compensation expenses, where applicable.  Management believes this non-GAAP information is useful for investors, taken in conjunction with Gilead’s GAAP financial statements, because management currently uses such information internally for its operating, budgeting and financial planning purposes. Non-GAAP information is not prepared under a comprehensive set of accounting rules and should only be used to supplement an understanding of Gilead’s operating results as reported under U.S. GAAP.

($ in millions, except percentages and per share amounts)

Net Product Sales

Non-GAAP Product Gross Margin*

Non-GAAP Expenses

R & D*

S G & A*

Effective Tax Rate

Diluted EPS Impact of Acquisition, Restructuring and Stock-Based Compensation Expenses

$ 7,400 – 7,500

$ 0.27 – 0.30

$ 900 – 920

$ 850 – 870

25% – 26%

75% – 77%

Provided on 4/20/10

$ 7,300 – 7,400^

$ 0.25 – 0.28^^^

$ 900 – 920

$ 850 – 870

26.5% – 27.5%^^

75% – 77%

Updated on 7/20/10

^ Reduction in net product sales guidance for full year 2010 was driven by the impact of foreign currency fluctuations.

^^ Increase in effective tax rate for full year 2010 was driven by higher U.S. revenue growth and lower revenues in Europe.

^^^ Decreases in diluted EPS impact of acquisition, restructuring and stock-based compensation expenses for full year 2010 was driven by lower projections of stock-based compensation expenses, partially offset by higher restructuring expenses related to our decision to close operations in Durham, North Carolina.

Looking Ahead

Continued commitment to R&D – new targets, new treatments for HIV

Expand Gilead Access Program

– Build on existing generic partnerships

– As approved, introduce new products into program (e.g., TMC278 fixed-dose regimen)

UNITAID Patent Pool

– Gilead is actively participating in discussions to move this important initiative forward

– Like partnerships with generic manufacturers, a patent pool could increase access by lowering prices, while respecting IP

Evaluate participation in new efforts for expanding access while encouraging innovation

Thank You