---

---

---

ITEM  1.	BUSINESS

---

•

Stribild (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) is a complete once-daily single tablet regimen for HIV-1 infection for treatment-naive adults. Stribild combines four compounds in one daily tablet and was approved by the FDA in August 2012. We filed a marketing authorization application for Stribild with the European Medicines Agency (EMA) in December 2011. We expect to receive approval from the European Commission in the second quarter of 2013.

---

•

Complera/Eviplera is an oral formulation dosed once a day for the treatment of HIV-1 infection in treatment-naïve adults. The product, marketed in the United States as Complera and in Europe as Eviplera, is the second complete single tablet regimen for the treatment of HIV and is a fixed-dose combination of our antiretroviral medications, Viread (tenofovir disoproxil fumarate) and Emtriva (emtricitabine), and Janssen's non-nucleoside reverse transcriptase inhibitor, Edurant (rilpivirine).

•

Atripla (efavirenz 600 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) is an oral formulation dosed once a day for the treatment of HIV infection in adults. Atripla is the first once-daily single tablet regimen for HIV intended as a stand alone therapy or in combination with other antiretrovirals. It is a fixed-dose combination of our antiretroviral medications, Viread and Emtriva and Bristol Myers-Squibb Company's non-nucleoside reverse transcriptase inhibitor, Sustiva (efavirenz).

•

Truvada (emtricitabine and tenofovir disoproxil fumarate) is an oral formulation dosed once a day as part of combination therapy to treat HIV infection in adults. It is a fixed-dose combination of our antiretroviral medications, Viread and Emtriva. In 2012, the FDA also approved Truvada, in combination with safer sex practices, to reduce the risk of sexually acquired HIV-1 infection in adults at high risk, a strategy called pre-exposure prophylaxis (PrEP).

•

Viread is an oral formulation of a nucleotide analog reverse transcriptase inhibitor, dosed once a day as part of combination therapy to treat HIV infection in patients 2 years of age and older. In 2012, the European Commission also approved the use of Viread in combination with other antiretroviral agents for the treatment of HIV-1 infected pediatric patients aged 2 to less than 18 years with nucleoside reverse transcriptase inhibitor resistance or toxicities precluding the use of first line pediatric agents. Viread is also approved for the treatment of chronic HBV in adults.

•	Emtriva is an oral formulation of a nucleoside analog reverse transcriptase inhibitor, dosed once a day as part of combination therapy to treat HIV infection in adults. In the United States and Europe, Emtriva is also available as an oral solution approved as part of combination therapy to treat HIV infection in children.

•

Viread is an oral formulation of a nucleotide analog reverse transcriptase inhibitor, dosed once a day for the treatment of chronic HBV in adults with compensated and decompensated liver disease. We licensed to GlaxoSmithKline Inc. (GSK) the rights to commercialize Viread for the treatment of chronic HBV in China, Japan and Saudi Arabia. In 2012, the European Commission approved the use of Viread for the treatment of chronic HBV infection in adolescent patients aged 12 to less than 18 years with compensated liver disease and evidence of immune active disease. Viread is also approved for the treatment of HIV infection in patients 2 years of age and older in combination with other antiretroviral agents.

•	Hepsera (adefovir dipivoxil) is an oral formulation of a nucleotide analog polymerase inhibitor, dosed once a day to treat chronic HBV in patients 12 years of age and older. We licensed to GSK the rights to commercialize Hepsera for the treatment of chronic HBV in Asia, Latin America and certain other territories.

•

Letairis (ambrisentan) is an oral formulation of an endothelin receptor antagonist (ERA) indicated for the treatment of pulmonary arterial hypertension (PAH) (WHO Group 1) in patients with WHO Class II or III symptoms to improve exercise capacity and delay clinical worsening. We sublicensed to GSK the rights to ambrisentan, marketed by GSK as Volibris (ambrisentan), for PAH in territories outside of the United States.

•	Ranexa (ranolazine) is an extended-release tablet for the treatment of chronic angina. We have licensed to Menarini International Operations Luxembourg SA the rights to Ranexa in territories outside of the United States.

•

Lexiscan/Rapiscan (regadenoson) injection is indicated for use as a pharmacologic stress agent in radionuclide myocardial perfusion imaging (MPI), a test that detects and characterizes coronary artery disease, in patients unable to undergo adequate exercise stress. Astellas US LLC has exclusive rights to manufacture and sell regadenoson under the name Lexiscan in the United States, subject to its obligations to pay us royalties based on sales of Lexiscan in the U.S. Rapidscan Pharma Solutions, Inc. (RPS) holds the exclusive right to manufacture and sell regadenoson under the name Rapiscan in Europe and certain territories outside the United States. We receive royalties from Astellas and RPS for sales in these territories.

---

•	Cayston (aztreonam for inhalation solution) is an inhaled antibiotic for the treatment of respiratory systems in cystic fibrosis (CF) patients 7 years of age and older with Pseudomonas aeruginosa (P. aeruginosa).

•

Tamiflu (oseltamivir phosphate) is an oral antiviral available in capsule form for the treatment and prevention of influenza A and B. Tamiflu is approved for the treatment of influenza in children and adults in more than 60 countries, including the United States, Japan and the European Union. Tamiflu is also approved for the prevention of influenza in children and adults in the United States, Japan and the European Union. We developed Tamiflu with F. Hoffmann-La Roche Ltd (together with Hoffmann-La Roche Inc., Roche). Roche has the exclusive right to manufacture and sell Tamiflu worldwide, subject to its obligation to pay us royalties based on a percentage of the net sales of Tamiflu.

•	AmBisome (amphotericin B liposome for injection) is a proprietary liposomal formulation of amphotericin B, an antifungal agent to treat serious invasive fungal infections caused by various fungal species in adults. Our corporate partner, Astellas Pharma US, Inc., promotes and sells AmBisome in the United States and Canada, and we promote and sell AmBisome in Europe, Australia and New Zealand.

•	Vistide (cidofovir injection) is an antiviral injection for the treatment of cytomegalovirus retinitis in adult patients with AIDS.

•

Macugen (pegaptanib sodium injection) is an intravitreal injection of an anti-angiogenic oligonucleotide for the treatment of neovascular age-related macular degeneration. Macugen was developed by Eyetech Inc. (Eyetech) using technology licensed from us and is now promoted in the United States by Valeant Pharmaceuticals, Inc. (Valeant), which acquired Eyetech in 2012. Valeant holds the exclusive rights to manufacture and sell Macugen in the United States, and Pfizer Inc. (Pfizer) holds the exclusive right to manufacture and sell Macugen in the rest of the world. We receive royalties from Valeant and Pfizer based on sales of Macugen worldwide.

---

•

PharmaChem Technologies (Grand Bahama), Ltd (PharmaChem). In 2005, PharmaChem, one of our commercial manufacturing partners, established a facility in The Bahamas to manufacture tenofovir disoproxil fumarate, the active pharmaceutical ingredient in Viread and one of the active pharmaceutical ingredients in Atripla and Truvada, for resource limited countries through a cooperative effort with PharmaChem and the Grand Bahama Port Authority.

•

Aspen Pharmacare Holdings Ltd (Aspen). In 2005, we entered into a non-exclusive manufacturing and distribution agreement with Aspen, providing for the manufacture and distribution of Viread and Truvada for the treatment of HIV infection to certain developing world countries included in our Gilead Access Program. In 2007, we amended our agreement with Aspen. Under the amended agreement, Aspen retained the right to manufacture and distribute Viread and Truvada for the treatment of HIV infection in these developing world countries. Aspen has the right to purchase Viread and Truvada in unlabeled bottles from us for distribution in such countries, and also has the right to manufacture Viread and Truvada using active pharmaceutical ingredient that has been purchased by Aspen from suppliers approved by us. Aspen was also granted the right to manufacture and distribute generic versions of emtricitabine and tenofovir disoproxil fumarate, including versions of tenofovir disoproxil fumarate in combination with emtricitabine for the treatment of HIV infection. Aspen is required to pay us royalties on net sales of Viread and Truvada, as well as royalties on net sales of generic versions of tenofovir disoproxil fumarate, including versions of tenofovir disoproxil fumarate in combination with generic versions of emtricitabine that are manufactured and distributed by Aspen.

---

•

Licenses with Generic Manufacturers. We have entered into non-exclusive license agreements with Indian generic manufacturers, granting them rights to produce and distribute generic versions of tenofovir disoproxil fumarate for the treatment of HIV infection to low income countries around the world, which includes India and many of the low income countries in our Gilead Access Program. The agreements require that the generic manufacturers meet certain national and international regulatory and quality standards and include technology transfers to enable expeditious production of large volumes of high quality generic versions of tenofovir disoproxil fumarate. In addition, these agreements allow for the manufacture of commercial quantities of both active pharmaceutical ingredient and finished product. In 2011, we expanded these non-exclusive license agreements to increase the number of countries included in the license, and also to include rights to Stribild and our future product candidates, elvitegravir, an investigational integrase inhibitor; and cobicistat, a pharmacoenhancing or "boosting" agent that increases blood levels to allow once-daily dosing of certain HIV medicines. To expand access to Viread for the treatment of HBV treatment in developing countries, we also included in these non-exclusive license agreements the ability to manufacture and distribute generic versions of tenofovir disoproxil fumarate for the treatment of HBV in the same countries where they are authorized to sell generic versions of tenofovir disoproxil fumarate for HIV. In August 2012, we announced new collaborations with Indian partners to produce and distribute generic emtricitabine in the developing world, including single tablet regimens containing emtricitabine and fixed-dose combinations of emtricitabine co-formulated with other Gilead HIV medicines.

•

Merck. In 2006, we entered into an agreement with an affiliate of Merck pursuant to which Gilead and Merck provide Atripla at substantially reduced prices to HIV infected patients in developing countries in Africa, the Caribbean, Latin America and Southeast Asia. Under the agreement, we manufacture Atripla using efavirenz supplied by Merck, and Merck handles distribution of the product in the countries covered by the agreement.

•

International Partnership for Microbicides (IPM) and CONRAD. In 2006, we entered into an agreement under which we granted rights to IPM and CONRAD, a cooperating agency of the U.S. Agency for International Development committed to improving reproductive health by expanding the contraceptive choices of women and men, to develop, manufacture, and, if proven efficacious, arrange for the distribution in resource limited countries of certain formulations of tenofovir for use as a topical microbicide to prevent HIV infection.

•

Medicines Patent Pool (the Pool). In 2011, we entered into an agreement with the Pool, an organization that was established by the United Nations to increase global access to high-quality, low-cost antiretroviral therapy through the sharing of patents. We granted the Pool a non-exclusive license to identify generic pharmaceutical manufacturers in India who specialize in high-quality production of generic medicines and granted sublicenses to those Indian manufacturers to manufacture and distribute generic versions of our antiretrovirals in the developing world. Sublicensees through the Pool will be free to develop combination products and pediatric formulations of our HIV medicines. We also granted the Pool the right to grant sublicenses to generic versions of Stribild and to our product candidates, elvitegravir and cobicistat, to those same generic pharmaceutical manufacturers in India for distribution in the developing world.

•	Janssen. In 2011, we expanded our agreement with Janssen, formerly Tibotec Pharmaceuticals, to provide for distribution of Complera/Eviplera for the treatment of HIV in less developed countries and to enable the commercialization of generic versions of the product.

---

•	efficacy;

•	safety;

•	tolerability;

•	acceptance by doctors;

•	ease of patient compliance;

•	patent protection;

•	ease of use;

•	price;

•	insurance and other reimbursement coverage;

•	distribution; and

•	marketing.

---

---

•

BMS. In 2004, we entered into a collaboration arrangement with BMS to develop and commercialize the single tablet regimen of our Truvada and BMS's Sustiva in the United States. This combination was approved for use in the United States in 2006 and is sold under the brand name Atripla. We and BMS structured this collaboration as a joint venture and operate as a limited liability company named Bristol-Myers Squibb & Gilead Sciences, LLC, which we consolidate. We and BMS granted royalty free sublicenses to the joint venture for the use of our respective company owned technologies and, in return, were granted a license by the joint venture to use any intellectual property that results from the collaboration. In 2006, the joint venture's collaboration agreement was amended to allow the joint venture to sell Atripla into Canada. The economic interests of the joint venture held by us and BMS (including share of revenues and out-of-pocket expenses) are based on the portion of the net selling price of Atripla attributable to efavirenz and Truvada. Since the net selling price for Truvada may change over time relative to the net selling price of efavirenz, both our and BMS's respective economic interests in the joint venture may vary annually. Since the second quarter of 2011, except for a limited number of activities that will be jointly managed, the parties no longer coordinate detailing and promotional activities in the United States, and the parties have reduced their joint promotional efforts since we launched Complera in August 2011 and Stribild in August 2012. The agreement will continue until terminated by the mutual agreement of the parties. In addition, either party may terminate the other party's participation in the collaboration within 30 days after the launch of at least one generic version of such other party's single agent products (or the double agent products). The non-terminating party then has the right to continue to sell Atripla, but will be obligated to pay the terminating party certain royalties for a three-year period following the effective date of the termination.

•

GSK. As a result of our acquisition of Myogen, Inc. (Myogen) in 2006, we assumed all rights to the March 2006 license and distribution and supply agreements between Myogen and GSK. Under the terms of the license agreement, GSK has exclusive rights to market ambrisentan (the active pharmaceutical ingredient in Letairis) under the name Volibris for pulmonary arterial hypertension in territories outside of the United States. Under the license agreement, we received an up-front payment of $20.0 million and, subject to the achievement of specific milestones, we are eligible to receive total additional milestone payments of $80.0 million. Through December 31, 2012, we have received $55.0 million of such potential milestone payments. In addition, we receive royalties based on net sales of Volibris in the GSK territories. GSK has an option to negotiate from us an

---

•

Janssen. In 2009, we entered into a collaboration agreement with Janssen to develop and commercialize a fixed-dose combination of our Truvada and Janssen's rilpivirine. This combination was approved in the United States and European Union in 2011 and is sold under the brand name Complera in the United States and Eviplera in the European Union. Under the agreement, Janssen granted us an exclusive license to Complera/Eviplera worldwide excluding certain middle income and developing world countries and Japan. Neither party is restricted from combining its drugs with any other drugs.

---

•

Japan Tobacco. In 2005, we entered into a licensing agreement with Japan Tobacco, under which Japan Tobacco granted us exclusive rights to develop and commercialize elvitegravir, a novel HIV integrase inhibitor, in all countries of the world, excluding Japan, where Japan Tobacco would retain such rights. Under the agreement, we are responsible for seeking regulatory approval in our territories and are required to use diligent efforts to commercialize a product for the treatment of HIV infection. We will bear all costs and expenses associated with such commercialization efforts. Under the terms of the agreement, we paid an up-front license fee of $15.0 million and are obligated to make total potential milestone payments of up to $90.0 million upon the achievement of certain clinical, regulatory and commercial objectives. Additionally, we are obligated to pay royalties based on any net sales in the territories where we market the product. Through December 31, 2012, we have made total milestone payments of $48.0 million. The agreement and our obligation to pay royalties to Japan Tobacco will terminate on a product-by-product basis as patents providing exclusivity for the product expire or, if later, on the tenth anniversary of commercial launch for such product. We may terminate the agreement for any reason in which case the license granted by Japan Tobacco to us would terminate. Either party may terminate the agreement in response to a material breach by the other party.

---

---

---

---

---

*

In February 2013, Gilead and Teva reached an agreement in principle to settle the ongoing patent litigation concerning the four patents that protect tenofovir disoproxil fumarate in our Viread, Truvada and Atripla products. Under the agreement, Teva will be allowed to launch a generic version of Viread on December 15, 2017. The settlement agreement must be filed with the Federal Trade Commission and Department of Justice for their review before it is final.

---

---

---

---

---

---

---

•	Phase 1. The drug candidate is given to a small number of healthy human control subjects or patients suffering from the indicated disease, to test for safety, dose tolerance, pharmacokinetics, metabolism, distribution and excretion.

•	Phase 2. The drug candidate is given to a limited patient population to determine the effect of the drug candidate in treating the disease, the best dose of the drug candidate, and the possible side effects and safety risks of the drug candidate. It is not uncommon for a drug candidate that appears promising in Phase 1 clinical trials to fail in the more rigorous Phase 2 clinical trials.

•

Phase 3. If a drug candidate appears to be effective and safe in Phase 2 clinical trials, Phase 3 clinical trials are commenced to confirm those results. Phase 3 clinical trials are conducted over a longer term, involve a significantly larger population, are conducted at numerous sites in different geographic regions and are carefully designed to provide reliable and conclusive data regarding the safety and benefits of a drug candidate. It is not uncommon for a drug candidate that appears promising in Phase 2 clinical trials to fail in the more rigorous and extensive Phase 3 clinical trials.

---

---

---

•	our minimum base rebate amount owed to Medicaid on products reimbursed by Medicaid increased by 8%, and the discounts or rebates we owe to ADAPs and other Public Health Service entities which reimburse or purchase our products also increased by 8%;

•	we are required to extend rebates to patients receiving our products through Medicaid managed care organizations;

•	we are required to provide a 50% discount on products sold to patients while they are in the Medicare Part D “donut hole;” and

•	we, along with other pharmaceutical manufacturers of branded drug products, were required to pay a portion of a new industry fee (also known as the pharmaceutical excise tax), of $2.8 billion for 2012, calculated based on select government sales during the 2010 calendar year as a percentage of total industry government sales.

---

---

---

ITEM 1A.	RISK FACTORS

---

•

As our HIV products are used over a longer period of time in many patients and in combination with other products, and additional studies are conducted, new issues with respect to safety, resistance and interactions with other drugs may arise, which could cause us to provide additional warnings or contraindications on our labels, narrow our approved indications or halt sales of a product, each of which could reduce our revenues.

•	As our HIV products mature, private insurers and government payers often reduce the amount they will reimburse patients for these products, which increases pressure on us to reduce prices.

•	A large part of the market for our HIV products consists of patients who are already taking other HIV drugs. If we are not successful in encouraging physicians to change patients' regimens to include our HIV products, the sales of our HIV products will be limited.

•	As generic HIV products are introduced into major markets, our ability to maintain pricing and market share may be affected.

---

•	our minimum base rebate amount owed to Medicaid on products reimbursed by Medicaid increased by 8%, and the discounts or rebates we owe to ADAPs and other Public Health Service entities which reimburse or purchase our products also increased by 8%;

•	we are required to extend rebates to patients receiving our products through Medicaid managed care organizations;

•	we are required to provide a 50% discount on products sold to patients while they are in the Medicare Part D “donut hole;” and

•	we, along with other pharmaceutical manufacturers of branded drug products, were required to pay a portion of a new industry fee (also known as the pharmaceutical excise tax) of $2.8 billion for 2012, calculated based on select government sales during the 2010 calendar year as a percentage of total industry government sales.

---

---

---

---

•	we are unable to control the resources our corporate partners devote to our programs or products;

•	disputes may arise with respect to the ownership of rights to technology developed with our corporate partners;

•	disagreements with our corporate partners could cause delays in, or termination of, the research, development or commercialization of product candidates or result in litigation or arbitration;

•	contracts with our corporate partners may fail to provide significant protection or may fail to be effectively enforced if one of these partners fails to perform;

•	our corporate partners have considerable discretion in electing whether to pursue the development of any additional products and may pursue alternative technologies or products either on their own or in collaboration with our competitors;

•	our corporate partners with marketing rights may choose to pursue competing technologies or to devote fewer resources to the marketing of our products than they do to products of their own development; and

•	our distributors and our corporate partners may be unable to pay us, particularly in light of current economic conditions.

---

•	not provide us with accurate or timely information regarding their inventories, patient data or safety complaints;

•	not effectively sell or support Cayston or Letairis;

•	not devote the resources necessary to sell Cayston or Letairis in the volumes and within the time frames that we expect;

•	not be able to satisfy their financial obligations to us or others; or

•	cease operations.

---

•	obtain patents and licenses to patent rights;

•	preserve trade secrets;

•	defend against infringement and efforts to invalidate our patents; and

•	operate without infringing on the property of others.

---

---

---

---

---

---

ITEM  1B.	UNRESOLVED STAFF COMMENTS

ITEM 2.	PROPERTIES

---

ITEM  3.	LEGAL PROCEEDINGS

---

---

---

ITEM  4.	MINE SAFETY DISCLOSURES

---

ITEM  5.	MARKET FOR REGISTRANT'S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES

---

(1)	This section is not “soliciting material,” is not deemed “filed” with the SEC and is not to be incorporated by reference in any of our filings under the Securities Act or the Exchange Act whether made before or after the date hereof and irrespective of any general incorporation language in any such filing.

(2)	Shows the cumulative return on investment assuming an investment of $100 in our common stock, the NBI Index and the S&P500 Index on December 31, 2007.

(1)	In January 2011, we announced that our Board authorized a three-year, $5.00 billion stock repurchase program, which expires in January 2014.

(2)	The difference between the total number of shares purchased and the total number of shares purchased as part of publicly announced programs is due to shares of common stock withheld by us from employee restricted stock awards in order to satisfy our applicable tax withholding obligations.

---

ITEM 6.	SELECTED FINANCIAL DATA

(1)	During 2012, we recorded $100.1 million and $93.8 million of stock-based compensation in research and development (R&D) expenses and selling, general and administrative expenses, respectively, related to the acquisition of Pharmasset.

(2)	Net income per share and the number of shares used in the per share calculations for all periods presented reflect the two-for-one stock split in the form of a stock dividend effective on January 25, 2013.

(3)	During 2012, we completed the acquisition of Pharmasset and we recognized consideration transferred of $11.05 billion which was primarily recorded in intangible assets. We financed the transaction with approximately $5.20 billion in cash on hand, $2.15 billion in bank debt issued in January 2012 and $3.70 billion in senior unsecured notes issued in December 2011.

(4)	During 2012, we borrowed $750.0 million under our five-year revolving credit facility credit agreement.

---

ITEM 7.	MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

•	completed the $11.05 billion acquisition of Pharmasset, Inc. (Pharmasset), acquired the lead compound now known as sofosbuvir, a nucleotide analog being evaluated for the treatment of HCV infection and accelerated our timeline to develop the first all-oral HCV regimen as a result of the acquisition;

•	expanded worldwide access to Complera/Eviplera, now available in 21 countries;

•	expanded our research and development (R&D) pipeline with over 50 active Phase 3 clinical studies at the end of 2012;

•

submitted marketing applications in the United States and European Union for elvitegravir, an integrase inhibitor for the treatment of HIV-1 infection in treatment-experienced adults, and cobicistat, a pharmacoenhancing or "boosting" agent that increases blood levels to allow once-daily dosing of certain HIV medicines. The U.S. Food and Drug Administration (FDA) has set target review dates of April 2013 under the Prescription Drug User Fee Act;

•	obtained FDA approval for and launched Stribild, our third single tablet regimen for the treatment of HIV in the United States;

•	announced the acquisition of YM Biosciences (YM), which closed in February 2013, and will expand our growing oncology/inflammation pipeline; and

•	obtained FDA approval for once-daily oral Truvada, in combination with safer sex practices, for pre-exposure prophylaxis (PrEP) to reduce the risk of HIV-1 infection among uninfected adults.

---

---

---

•	Atripla

•	Truvada

•	Complera/Eviplera

•	Stribild

---

---

---

---

---

---

---

•	the commercial performance of our current and future products;

•	the progress and scope of our R&D efforts, including preclinical studies and clinical trials;

•	the cost, timing and outcome of regulatory reviews;

•	the expansion of our sales and marketing capabilities;

•	administrative expenses;

•	the possibility of acquiring additional manufacturing capabilities or office facilities;

•	the possibility of acquiring other companies or new products;

•	costs associated with the settlement and conversion of our convertible senior notes and related warrants;

•	the establishment of additional collaborative relationships with other companies; and

•	costs associated with the defense, settlement and adverse results of litigation and government investigations.

---

---

•	estimates of revenues and operating profits related to the products or product candidates;

•	the probability of success for unapproved product candidates considering their stages of development;

•	the time and resources needed to complete the development and approval of product candidates;

•	the life of the potential commercialized products and associated risks, including the inherent difficulties and uncertainties in developing a product candidate such as obtaining FDA and other regulatory approvals; and

•	risks related to the viability of and potential alternative treatments in any future target markets.

---

---