Gilead initiates HIV integrase inhibitor trial
trial evaluating its latest HIV drug treatment that represents a
promising novel class of agents with the potential to inhibit HIV
replication, particularly for patients whose HIV has developed
resistance to other agents.
There is a certain degree of expectation attached to this latest treatment as scientists have intentionally targeted an enzyme that means chances of resistance to the treatment are reduced.
The development of resistance is a major problem with all currently available HIV/AIDS treatments. HIV's high degree of variability and adaptability means that the virus is able to change rapidly and usually develops resistance to treatments very quickly, rendering them ineffective.
HIV/AIDS drug resistance can be considered as a natural response to the selective pressure of drug treatments. However, it is exacerbated by several factors, including abuse, underuse or misuse of antimicrobials, poor patient compliance, and poor quality of available drugs.
At the last count in 2003, the World Health Organisation (WHO), estimated between 35-42 million people were living with HIV. In the same year, AIDS killed almost three million; over 20 million have died since the first cases of AIDS were identified in 1981.
The double-blind, randomised, placebo-controlled Phase I/II dose-escalation study will evaluate the tolerability, safety and antiviral activity of GS 9137 in HIV-positive patients.
GS 9137 is a novel HIV integrase inhibitor discovered by Japan Tobacco, Inc (JT) and licensed to Gilead in March 2005. The license granted Gilead exclusive rights to develop and commercialize GS 9137 in all countries of the world, excluding Japan where JT will retain rights. GS 9137 has been previously evaluated in a Phase I study in Japan to assess pharmacokinetics and safety in healthy volunteers.
Gilead has made quite a name for themselves in the field of HIV and AIDS research. Its nucleoside analog, Viread is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in adults. This indication is based on analyses of plasma HIV-1 RNA levels and CD4 cell counts in controlled studies of Viread in treatment-naïve and treatment-experienced adults.
On October 26, 2001, the US. Food and Drug Administration approved Viread for the treatment of HIV infection. In May 2003, the EMEA expanded the indication of Viread to include the product's use in antiretroviral-naïve HIV infected patients in all 15-member states of the European Union.
With the extension of this indication, Viread is now approved in Europe for broad use in combination with other antiretrovirals for the treatment of HIV-1 infected adults over 18 years of age, including patients initiating antiretroviral therapy as well as previously treated patients.
Its other HIV treatment, Emtriva (emtricitabine) is indicated in combination with other antiretroviral agents for the treatment of HIV infection in adults. This indication is based on the analyses of plasma HIV RNA levels and CD4 cell counts in two Phase III clinical trials of Emtriva of 48 weeks duration.
In July 2003, Emtriva was cleared for marketing in the United States by the Food and Drug Administration (FDA). An application for marketing approval of Emtriva for the treatment of HIV was filed with the European regulatory authorities in December 2002.
On July 24, 2003 the Committee for Proprietary Medicinal Products (CPMP), the scientific committee of the European Medicines Evaluation Agency (EMEA), issued a positive opinion on Emtriva. And in October 2003, the European Commission granted Marketing Authorisation for Emtriva in all 15-member states of the European Union.
The drug also currently being evaluated as a potential treatment for chronic hepatitis B.
According to a report by the financial services firm Griffin Securities, the worldwide HIV market is expected to triple in size by 2007, growing from a $5 billion (€4.1 billion) in sales to over $13 billion in sales by 2007. Growth in the HIV market will continue to be driven by a rapidly growing HIV and AIDS population.
In the absence of therapeutic intervention, the vast majority of individuals infected with HIV will ultimately develop AIDS, on average in about 10 years, which has a mortality rate approaching 100 per cent. Experts say that the drugs currently available only extend life, on average, 1.8 years
