July 22, 2014
An analysis of 120 Australians who are taking two or more of four older antiretrovirals -- called RATE drugs -- concluded that the vast majority could switch to drug regimens with newer medications that are better tolerated.
The study, published in PLOS ONE, looked at the treatment history and drug resistance profile of participants, as well as tropism testing for maraviroc (Selzentry, Celsentri) where possible (only available for 38% of people studied). The RATE drugs in question are ritonavir (Norvir), abacavir (Ziagen), tenofovir (Viread) and efavirenz (Sustiva, Stocrin), one or more of which is prescribed to the majority of patients on antiretroviral therapy. Side effects that may be avoided with a RATE-sparing drug regimen include problems with drug interactions, allergic reactions, lower effectiveness at higher viral loads, higher risk for cardiovascular disease, reduced bone density, kidney dysfunction, neuropsychiatric disturbances and an increase in lipid levels.
Novel drug regimens that the researchers considered viable used rilpivirine (Edurant), etravirine (Intelence), atazanavir (Reyataz), raltegravir (Isentress) and maraviroc, as well as the older lamivudine (3TC, Epivir). Depending on susceptibility to maraviroc, 98% of study participants (if all are susceptible to maraviroc, 94% given unknown susceptibility) could switch to a regimen with at least two safer active drugs and 89% (if everyone is susceptible to maraviroc, 87% for unknown susceptibility) could switch to one with three safer medications.
The study also found that 57% of Australians on antiretroviral medications are taking two or more RATE drugs and may benefit from switching to these novel regimens. The study authors did caution, however, that "most of the regimens considered as 'viable' in this study have not been rigorously tested in clinical trials and might be regarded as unconventional." The authors concluded that randomized, controlled trials would be necessary to determine the advantages and disadvantages of switching stable patients to newer RATE-sparing medication regimens.
Barbara Jungwirth is a freelance writer and translator based in New York.
Follow Barbara on Twitter: @reliabletran.
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