Because of their effectiveness, safety profiles and convenience, single tablet regimens have become a standard of care for HIV. A single tablet regimen combining the multiple drugs required for HIV treatment helps ensure patients take all of their medicine, avoiding partial doses which can lead to resistance to therapy. To this end, in 2012 we achieved a significant milestone: the approval by the U.S. Food and Drug Administration (FDA) of Stribild, a fixed-dose formulation of four Gilead medicines in a once-daily pill for treatment-naïve patients. It’s our third single tablet regimen for HIV, joining Atripla® and Complera®, which are among the most-prescribed antiretroviral regimens in the United States and Europe.
In July 2012, Truvada® became the first product approved by FDA in combination with safer sex practices to reduce the risk of HIV in uninfected adults at high risk, a strategy called pre-exposure prophylaxis (PrEP). At the 2012 International AIDS Conference—the largest gathering of scientists, clinicians, public health experts and advocates committed to eradicating the disease—a sense of growing optimism prevailed. The approval of Truvada for PrEP was noted as a milestone that could help slow the spread of HIV in communities at greatest risk, offering new hope for bringing the epidemic under control. While great progress in diagnosis and linkage to care for individuals with HIV has occurred in the last several years, HIV prevention remains a challenge around the world.
Current interferon-based regimens available for treating hepatitis C remain a challenge for patients due to safety issues, side effects, variable response rates and burdensome injections. Because of this, Gilead is advancing the development of all-oral hepatitis C medicines with the goal of improving tolerability and convenience and increasing cure rates. In November 2012, we reported a 100 percent sustained virologic response rate (SVR4*) for treatment-naïve genotype 1 hepatitis C patients enrolled in a Phase 2 trial evaluating an all-oral combination of sofosbuvir (GS-7977) and ledipasvir (GS-5885) with ribavirin. Based on these data, sofosbuvir and ledipasvir have been co-formulated into a single pill, which is now being studied in Phase 3 trials.
Following the acquisition of Pharmasset in January 2012, we moved quickly to expand clinical testing of hepatitis C therapies. Phase 3 trials exploring sofosbuvir in various combinations with other agents in genotype 1-6 patient populations are ongoing. In 2012, there were 21 new studies initiated, enrolling more than 2,680 participants, and because of patient and provider interest, we were able to complete enrollment of some of these trials within weeks. In addition to evaluating multiple hepatitis C drug combinations in diverse genotypes and patient populations, we are investigating ways to shorten therapy from one year to a matter of weeks.
*HCV RNA undetectable four weeks after completing therapy.
Scientific understanding of the biological mechanisms underlying cancer is rapidly increasing—and this understanding is leading to potential breakthroughs in therapy. One area of focus at Gilead involves investigational new agents that specifically target intracellular signaling pathways responsible for tumor growth. Another approach involves targeting the extracellular matrix, which supports the system that helps enable solid tumor growth. Importantly, certain targeted agents may have fewer side effects than conventional treatments, such as chemotherapy.
At Gilead, we are developing new treatment options that may target a range of cancers. We are also exploring the utility of medications used as combination therapy for diseases that are among the most difficult to treat. Our work is informed by a robust understanding of biology and focuses on interrupting key pathways involved in the formation and replication of cancerous cells.