March 2, 2011
From CROI, March 2011: The HIV drug tenofovir (Viread, Truvada) has become a preferred therapy in the US Guidelines for people going on HIV treatment for the first time. Gilead, who makes that drug, is now studying a new “prodrug” version of tenofovir currently called GS7340 with hopes that it provides better control of HIV. So far in the lab it provides a higher concentration of drug inside cells at perhaps a lower dose than the current tenofovir, and may even permeate lymph cells.
In this 14-day study, two doses of GS7340 (50 and 150mg) were given once and twice a day to 30 people who had never been on HIV treatment. These doses were compared to current dose of tenofovir, for a total of 10 people in each of three groups. Everyone had CD4 counts above 200 (average 424) and viral loads above 15,000. Of those who participated, 90% were male, 43% were white, and were 23-54 years of age.
The results showed an average 1.71 log decrease in viral load in people on the 150mg dose, and an average 1.57 log decrease on 50mg. (The minimum desired change is a 1.0 log decrease.) No serious side effects or lab abnormalities were reported, and headaches and nausea were mild to moderate. No resistance was seen. The company believes that this new version can be developed as single pill regimens with other drugs, something that isn’t possible with the current formulation of tenofovir.
Due to the short length of this study, it’s unknown how GS7340 impacts kidney or bone health, as is seen with the current form of tenofovir. This will need to be addressed as it moves through further study. Data is also not yet available of how GS7340 performs against hepatitis B disease.
RESEARCH STUDY:
GS-7340 Demonstrates Greater Declines in HIV-1 RNA than TDF during 14 Days of Monotherapy in HIV-1-infected Subjects. Markowitz M, et al. Poster #152LB.