In 2006, nearly 500,000 patients in the United States were receiving antiretroviral therapy for HIV infection. Of these, approximately half were taking one or more Gilead HIV medications. However, the potential for growth remains. Approximately 400,000 people have been diagnosed with HIV but have not yet started treatment, and another 250,000 are estimated to be HIV-infected but are unaware of their status.
In addition, strong market growth was seen for Tamiflu, a product we invented and co-developed with our partner F. Hoffmann-La Roche Ltd (Roche) and one that is now sold worldwide by Roche. Tamiflu was initially developed for the treatment and prevention of seasonal flu but is now also seen as a key component in pandemic planning to prepare for the potential spread of the avian flu virus. Largely due to corporate planning and government stockpiling, Roche generated record sales of Tamiflu, resulting in royalty revenue recognized by Gilead of more than $364 million in 2006.
ENHANCED PRODUCT PIPELINE
We have several drugs in development that could further enhance our HIV and hepatitis franchises. Currently, we have a novel integrase inhibitor, GS 9137, in development for the treatment of HIV. Integrase inhibitors target a different stage in the HIV replication cycle than other currently marketed classes of drugs, and may, in combination with other antiretrovirals, effectively prevent the replication of the virus in the body, particularly resistant virus. We also have a novel compound in early clinical development, GS 9190, to treat hepatitis C.
Currently, treatment of HIV-positive patients is recommended when plasma HIV viral load exceeds 10,000 copies/mL and CD4 cell counts are between 200 and 350 cells/mm3. Many physicians and virologists now believe that earlier diagnosis and initiation of treatment may improve outcomes and also significantly reduce the spread of the disease. In September 2006, the U.S. Centers for Disease Control and Prevention (CDC) took the first step along this path and recommended routine, voluntary HIV screening in healthcare settings for all individuals ages 13 to 64. Improving HIV testing and diagnosis may help raise awareness of the disease, bring more people into care and potentially reduce the rate of new infections.
We have also continued to grow our hepatitis franchise, where Hepsera remains the most-prescribed antiviral treatment for chronic hepatitis B in the United States, despite increased competition in this market. Tenofovir disoproxil fumarate, the active agent in Viread, is in Phase III clinical trials for the treatment of chronic hepatitis B. This compound has the potential to be the growth driver for our hepatitis franchise, much in the same way it has been for our HIV portfolio.
