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Gilead’s research and development program identifies and evaluates investigational compounds that show potential to advance the treatment of life-threatening diseases in areas of unmet medical need. Safety and efficacy of the following compounds have not been established.
Gilead is working to develop next-generation HIV therapies for all individuals who live with the disease regardless of treatment status or age. Our focus on advancing treatment options resulted in the development of the investigational agent tenofovir alafenamide (TAF), a novel form of the active ingredient in Viread® (tenofovir disoproxil fumarate, or TDF). We believe that TAF-containing regimens have the potential to help appropriate HIV patients who face life-long antiretroviral therapy.
In 2014, encouraging results from Phase 3 clinical studies supported regulatory submissions in the United States and Europe for an investigational once-daily single tablet regimen (STR) containing elvitegravir, cobicistat, emtricitabine and TAF (E/C/F/TAF) for the treatment of HIV-1 infection in adults. These studies evaluated the use of E/C/F/TAF in diverse patient populations, including antiretroviral treatment-naïve adults, virologically suppressed adult patients who want to switch HIV treatment regimens, and adults with mild-to-moderate renal impairment. In these studies, E/C/F/TAF was shown to have similar efficacy in suppressing HIV, with an improved renal and bone safety profile compared to Stribild (E/C/F/TDF).
The regulatory filing timeline for an investigational combination of emtricitabine and TAF (F/TAF), a potential new HIV treatment “backbone” to be used in combination with other antiretroviral medicines, was also accelerated.
In addition, Gilead expanded its partnership with Janssen R&D Ireland to include the development and commercialization of R/F/TAF, which is an investigational STR combining F/TAF plus Janssen’s rilpivirine. Janssen is also developing D/C/F/TAF, an investigational STR containing Janssen’s darunavir in combination with cobicistat and F/TAF, which if approved would be the first protease inhibitor-containing STR.
More than half a billion people worldwide are infected with chronic hepatitis C virus (HCV) or hepatitis B virus (HBV), both of which over time play a primary role in the development of liver damage and liver failure.
Sovaldi® (sofosbuvir), a once-daily oral treatment used in combination with other antiviral medicines for treating chronic HCV infection, provides an important treatment option for many patients. In 2014, Harvoni® (ledipasvir/sofosbuvir) was approved, becoming the first once-daily single tablet regimen (STR) for the treatment of chronic hepatitis C (CHC) genotype 1 adult patients – the most prevalent genotype in the U.S. Harvoni represents a significant medical advancement because it is a simple regimen that eliminates the need for interferon and ribavirin while providing high cure rates in 12 weeks for most patients and as little as eight weeks for certain subgroups of treatment-naïve patients.
Gilead is also developing an investigational pan-genotypic STR that has the potential to effectively treat chronic HCV patients, regardless of HCV genotype. Investigational development programs are also underway that focus on other non-viral liver diseases such as nonalcoholic steatohepatitis, primary sclerosing cholangitis and liver fibrosis.
Viread® (tenofovir disoproxil fumarate), available for the treatment of chronic HBV infection, provides an option to help manage this chronic disease. For most patients, however, life-long therapy is required. Viread has demonstrated efficacy for chronic HBV sufferers, however, Gilead’s ultimate goal is to offer these patients a cure. Because the biology of HBV infection differs from that of HCV, developing a cure for HBV might require an approach that necessitates multiple drugs to inhibit viral replication and eliminate HBV DNA from all infected liver cells. Several clinical studies with differing approaches are ongoing to investigate this strategy.
Zydelig® (idelalisib), introduced in 2014, is a first-in-class PI3K delta inhibitor that offers appropriate patients with relapsed chronic lymphocytic leukemia (CLL), follicular lymphoma or small lymphocytic lymphoma, an important new option for managing their disease. In order to further characterize its potential clinical benefit, combination studies of Zydelig are being conducting in earlier stages of CLL and in indolent non-Hodgkin’s lymphoma. Zydelig provides Gilead a foundation on which to build a portfolio of novel cancer therapies, including regimens that have the potential to increase durable remission rates and survival for a variety of cancers.
Gilead’s portfolio of investigational targeted cancer therapies includes small molecules directed at multiple signaling pathways associated with B-cell malignancies, myelofibrosis and solid tumors – PI3K delta, Syk, JAK and BTK. In addition, an investigational anti-MMP9 antibody is under evaluation in gastric cancer and other solid tumors.
In the area of cardiovascular disease, Gilead is focused on further developing knowledge and use of Letairis® and Ranexa®, and developing novel compounds with the potential to impact patient populations with unmet medical needs.
Letairis, an endothelin receptor antagonist approved in 2007, is an important treatment option for patients with pulmonary arterial hypertension (PAH). The AMBITION study evaluated Letairis in combination with tadalafil as an initial treatment regimen for PAH patients with WHO Functional Class II and III symptoms. Based on results showing a significant reduction in the risk of clinical failure compared to either drug alone, a supplemental new drug application was filed with the U.S. Food and Drug Administration. If approved, Letairis may be indicated for use with tadalafil as an up-front combination therapeutic regimen for PAH. Additional efforts to support the goal of improving therapeutic options for patients with PAH are also underway – a clinical study of an ASK-1 inhibitor is being conducted in this patient population.
Building on the knowledge we have gained regarding the cardiac late sodium current, we are investigating new treatments that may benefit patients with cardiovascular conditions that currently lack effective therapies. An investigational compound that selectively inhibits the late sodium current is being evaluated for life-threatening heart diseases, including long QT-3 syndrome, hypertrophic cardiomyopathy and ventricular tachycardia/ventricular fibrillation.
In addition, we continue to build our knowledge of Ranexa, a drug approved for the treatment of chronic angina. Results from the RIVER-PCI study examining its potential impact on outcomes in patients who have undergone percutaneous coronary intervention (stenting) are expected later this year.
Cystic fibrosis (CF) is a life-threatening genetic condition that mainly affects the lungs and digestive track. Cayston®, an inhaled antibiotic approved in 2010, treats Pseudomonas aeruginosa, a bacterial lung infection that is a primary cause of sickness and hospitalizations in patients with CF. Cayston is included in CF treatment guidelines and provides patients with an effective option for managing their condition.
There is no effective therapy for respiratory syncytial virus (RSV), which accounts for more than 300,000 hospitalizations each year in the United States in infants and adults. In 2014, Gilead reported promising Phase 2a data from a clinical study for an investigational therapy to treat RSV infection, and based on these data in healthy adults, additional studies in a variety of RSV-infected populations are underway, including bone marrow transplant patients and hospitalized adults with upper or lower respiratory tract RSV infection.
In addition, the investigational monoclonal antibody simtuzumab is being evaluated as a potential treatment for idiopathic pulmonary fibrosis (IPF), a fatal disease that causes scarring and reduced function of the lungs. Our current clinical trial will determine if simtuzumab reduces the severity of lung damage in patients with IPF. If successful, simtuzumab may be studied in other fibrotic diseases such as scleroderma.
Patients with diabetes often develop injury to the kidney that can lead to loss of kidney function. GS-4997 is thought to block a pathway that causes inflammation and scarring, and the investigational agent is being studied in diabetics with kidney damage in hopes of slowing the progression of disease. Additionally, GS-5745 is an investigational agent being studied in inflammatory diseases that involve several different organ systems, including ulcerative colitis, Crohn’s disease, rheumatoid arthritis and lung diseases.