September 30, 2008

Once-Daily Prezista as Good as Twice-Daily Dose for Some

Once-daily Norvir (ritonavir)-boosted Prezista (darunavir) is as effective as standard twice-daily dosing for some treatment-experienced patients, according to a study published in the October issue of the Journal of Acquired Immune Deficiency Syndromes.

Although Tibotec’s Prezista is currently being studied as an 800 mg once-daily option in people who’ve never started antiretroviral (ARV) therapy, the U.S. Food and Drug Administration (FDA) has approved it only for HIV-positive people who have used other ARVs in the past, at a dose of 600 mg twice daily combined with 100 mg Norvir.

To determine whether once-daily administration may be just as safe and effective as twice-daily Prezista in treatment-experienced patients, Sandra De Meyer, PhD, from Tibotec and her colleagues conducted a clinical trial involving 162 HIV-positive volunteers. The patients, all of whom had failed several different ARV combinations in the past but didn’t have evidence of HIV mutations known to confer resistance to Prezista, were allotted to one of three groups. The first group took 800 mg Prezista plus 100 mg Norvir once daily; the second group took 600 mg Prezista plus 100 mg Norvir twice a day; and the third group took other currently available protease inhibitors.

De Meyer’s team found that 67 percent of those taking Prezista once daily achieved and maintained a viral load of less than 50 copies for 24 weeks, compared with 62 percent of those taking Prezista twice daily. Only 11 percent of those taking another protease inhibitor achieved an undetectable viral load. CD4 cell increases were similar between the once- and twice-daily Prezista groups.

Although once-daily Prezista appears safe and effective in treatment-experienced patients with no Prezista resistance, the authors conclude, patients and their providers should wait for the results of a larger and longer trial, called ODIN, before trying this dosing strategy.

Search: Prezista, darunavir, Norvir, ritonavir, once-daily, Sandra De Meyer, Tibotec

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