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Reyataz In Review: Part 1 – Simplified Reyataz-Based Regimens May Effectively Control HIV

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Published: Dec 15, 2011 12:21 pm
Reyataz In Review: Part 1 – Simplified Reyataz-Based Regimens May Effectively Control HIV

This article is the first of a two-part series on a review of Reyataz-related treatments and side effects. The first part discusses recent results on simplified Reyataz-based antiretroviral regimens; the second part discusses side effects associated with Reyataz.

A review of Reyataz-related studies at a recent conference suggests that simplified two-drug regimens using Norvir-boosted Reyataz may be as effective as three-drug regimens in patients with well-controlled HIV infection.

According to the review authors, the findings are exciting since treatment simplification and fewer side effects are likely to improve adherence to antiretroviral therapy.

However, Dr. Eric Daar, Division Chief of HIV Medicine at the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, who was not affiliated with the studies or the review, warned that the results should be interpreted with caution.

“Based upon the results discussed here, and other data, I would suggest that such a [simplified two-drug] strategy is viable, but not necessarily supported by sufficient data to make it the standard of care,” said Dr. Daar. He added that this data could be used to justify larger randomized-controlled clinical trials to test the two-drug strategy further.

Reyataz (atazanavir) is a relatively new, once-daily protease inhibitor approved for HIV treatment by the U.S. Food and Drug Administration (FDA) in 2003. The U.S. Department of Health and Human Services treatment guidelines list Norvir (ritonavir)-boosted Reyataz plus Truvada (emtricitabine/tenofovir) as a preferred antiretroviral regimen for HIV-positive adults beginning treatment for the first time.

In this review, the authors discussed some of the most relevant recent findings related to Reyataz treatment that were presented at the 6th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention, held in Rome this past July (see related AIDS Beacon news).

Simplified Two-Drug Regimens Based On Norvir-Boosted Reyataz May Be As Effective As Three-Drug Regimens In Some Cases

Results from several studies showed that simplified two-drug regimens based on Norvir-boosted Reyataz were as safe and effective as three-drug regimens.

One small study evaluated the effect of simplifying antiretroviral regimens for HIV-positive adults with well-controlled viral load (amount of virus in the blood). Forty HIV-positive individuals with undetectable viral loads, and no known resistance to protease inhibitors or Epivir (lamivudine), participated in the study.

Participants switched from a regimen of Norvir-boosted Reyataz plus two nucleoside reverse transcriptase inhibitors (NRTIs) to a simplified regimen of Norvir-boosted Reyataz plus the NRTI Epivir. Results from the study suggested that the simplified treatment was safe, rarely resulted in virologic failure, and did not result in the development of drug resistance.

“The results are interesting but limited by the fact that it was a very select patient population, included relatively small [participant] numbers (n=40), and there was no control group,” said Dr. Daar.

“Nevertheless, the results are not surprising in light of other data showing that even Reyataz/Norvir alone in a related patient population was associated with low risk of virologic failure and lack of protease inhibitor resistance,” he added.

Another study showed that Reyataz plus Selzentry (maraviroc), a two-drug regimen, was as effective as Reyataz plus Truvada, which is a three-drug regimen.

Selzentry is a new type of antiretroviral drug approved for HIV treatment by the FDA in 2007. HIV requires the CCR5 protein, which is located on the surface of white blood cells, in order to attach to and infect these cells. Selzentry blocks CCR5, preventing HIV’s entry into the cells.

According to the review, a 48-week Phase 2 study compared the effectiveness of Selzentry plus Reyataz with Truvada plus Reyataz, both in treatment-naïve HIV-positive adults. Results from the study indicated that Selzentry-based treatment achieved viral suppression in a high proportion of patients (75 percent), with a comparable rate of side effects.

Reyataz May Suppress Viral Loads Better Than Prezista

Another study showed that Reyataz is as effective as Prezista (darunavir), another relatively new and commonly prescribed protease inhibitor.

Prezista was approved for by the FDA in 2006. Previous studies have shown that Prezista may have higher antiviral activity than Reyataz in the laboratory. According to the review, one study examined if this increased antiviral activity was associated with better viral suppression in previously untreated people with HIV.

Results showed that after a year of treatment, both regimens resulted in well-controlled viral loads, with all participants achieving viral loads of 200 copies per milliliter or less. However, Reyataz-treated individuals reached undetectable viral levels earlier and in greater proportion that people treated with Prezista.

The study authors concluded that the increased antiviral activity of Prezista did not result in a better clinical outcome than treatment with Reyataz.

For more information, please refer to the article in HIV and AIDS Review (abstract).

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