Sep 20, 2010
4 drug anti-HIV pill shows promise
A single pill containing 4 drugs to treat HIV infection has achieved promising results during trials, according to data presented at the 50th Interscience Conference on Antimicrobial Agents and Chemotherapy and reported in the Medscape HIV/AIDS journal.
Quad by Gilead Sciences contains elvitegravir, cobicistat, emtricitabine and tenofovir disoproxil fumarate and was highly effective in suppressing HIV and in helping patients boost their CD4 T cell counts. CD4 T cells are important in the body's response to HIV and tend to be targeted by the HIV virus itself. Boosting CD4 T cell counts is protective against many HIV related cancers and infections. Quad also apparently had better tolerance than the popular single pill 3 drug formulation Atripla.
Atripla has been a very effective and also very convenient way of delivering anti-HIV medications.
The study was carried out over 48 weeks. 71 patients were recruited, 48 given Quad and 23 were given Atripla. All the patients were new to HIV treatment with a HIV viral load of more than 5,000 and CD4 counts greater than 50. (HIV viral load is the amount of free HIV virus circulating in the blood and a normal CD4 count is between 400 and 1200)
At the end of the trial 90% of those taking Quad had HIV viral loads of less than 50compared to 83% of the Atripla group. Those taking Quad also experienced a rise in CD4 cells averaging 240 compared to 162 in those given Atripla.
The incidence of adverse reactions was similar in both groups but those taking Quad experienced fewer problems of the central nervous system.
Doctors welcomed the results of the trials. “These results suggest that Quad could be an important new option for people with HIV,” said lead author Dr Richard Elion from the Whitman Walker Clinic in Washington, DC. “The challenge is to make treatment simple and compress the number of pills that need to be taken. The bottom line is that our study showed that use of an experimental booster [cobicistat] in this regimen that includes an experiment integrase inhibitor [elivitegravir] achieved similar results to Atripla with improved tolerability.”
Dr Elion went on to explain that the experimenta1 booster cobicistat, unlike ritonavir, was amenable to coformulation with other antiretroviral drugs.
A further study on cobicistat involved giving 50 patients cobicistat-boosted atazanavir, emtricitabine, and tenofovir and comparing results to 29 patients who were given the same combination with cobicistat replaced with ritonavir.
The study again showed promise with patients in the cobicistat group experiencing an average rise in CD4 cell counts of around 230 compared to 206 in the ritonavir group. 82% of those taking cobicistat met the primary objective of an HIV viral load less than 50, compared to 86% of the ritonavir group.