The US Food and Drug Administration (FDA) has approved Gilead Sciences' Stribild  (elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg), a complete once-daily single tablet regimen for HIV-1 infection for treatment-naïve adults.

Stribild, referred to as “Quad” prior to FDA approval, combines four compounds in one daily tablet: elvitegravir, an integrase inhibitor; cobicistat, a pharmacoenhancing agent; emtricitabine and tenofovir disoproxil fumarate.

“Over the past decade, co-formulated HIV medicines have simplified therapy for many patients and have become standard of care,” said Paul Sax, MD, clinical director of the division of Infectious Diseases at Brigham and Women’s Hospital, Boston, Professor of Medicine at Harvard Medical School, and principal investigator of one of the Stribild pivotal studies. “Today’s approval of Stribild will provide physicians and their patients an effective new single tablet treatment option for individuals starting HIV therapy for the first time.”

The approval of Stribild is supported by 48-week data from two pivotal phase 3 studies in which the single tablet regimen met its primary objective of non-inferiority compared to Atripla (efavirenz 600 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) (Study 102) and to a regimen containing ritonavir-boosted atazanavir plus Truvada (emtricitabine/tenofovir disoproxil fumarate) (Study 103). Today’s approval is also supported by Chemistry, Manufacturing and Controls (CMC) information on the individual components of Stribild and the co-formulated single tablet regimen.

“For much of the company’s 25-year history, Gilead has focused on the development of improved treatments and simplified regimens for HIV,” said John C. Martin, PhD, chairman and chief executive officer, Gilead Sciences. “Therapies that address the individual needs of patients are critical to enhancing adherence and increasing the potential for treatment success, and we are proud to introduce a new single tablet regimen for the healthcare and patient communities.”

Stribild is the third single tablet HIV regimen developed by Gilead. The first, Atripla, was approved in 2006 and is marketed by Gilead and Bristol-Myers Squibb in the United States. The second single tablet regimen, Complera (emtricitabine/rilpivirine/tenofovir disoproxil fumarate), which combines Gilead’s Truvada and Janssen R&D Ireland’s rilpivirine, was approved in 2011.

In all studies of Stribild, most adverse events were mild to moderate. Stribild has Boxed Warnings of lactic acidosis/severe hepatomegaly with steatosis and post treatment acute exacerbation of hepatitis B; see below for important safety information.

Applications for marketing approval of Stribild are also pending in Australia, Canada and the European Union. In the developing world, Gilead has granted multiple Indian manufacturing partners and the Medicines Patent Pool the right to develop generic versions of Stribild and distribute them to 100 developing countries. These agreements include a complete technology transfer of the manufacturing process for the single tablet regimen.

Stribild contains four Gilead compounds in a complete once-daily, single tablet regimen: elvitegravir 150 mg; cobicistat 150 mg; emtricitabine 200 mg; and tenofovir disoproxil fumarate 300 mg. Stribild is indicated as a complete regimen for the treatment of HIV-1 infection in adults who are antiretroviral treatment-naïve. Stribild does not cure HIV-1 infection.

Elvitegravir is a member of the integrase inhibitor class of antiretroviral compounds. Integrase inhibitors interfere with HIV replication by blocking the ability of the virus to integrate into the genetic material of human cells. Elvitegravir was licensed by Gilead from Japan Tobacco Inc. (JT) in March 2005. Under the terms of Gilead’s agreement with JT, Gilead has exclusive rights to develop and commercialize elvitegravir in all countries of the world, excluding Japan, where JT retains rights. Gilead submitted a New Drug Application (NDA) to FDA for elvitegravir on June 27, 2012.

Cobicistat is a pharmacoenhancing or “boosting” agent that enables elvitegravir once-daily dosing. It is a potent mechanism-based inhibitor of cytochrome P450 3A (CYP3A), an enzyme that metabolizes drugs in the body. Cobicistat acts only as a pharmacoenhancer and has no antiviral activity. Gilead submitted an NDA to FDA for cobicistat on June 28, 2012.

Elvitegravir and cobicistat as standalone agents are investigational products and their safety and efficacy have not yet been established.

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need.