October 10, 2006 (AIDSmeds)—Norvir® (ritonavir)-boosted Reyataz® (atazanavir) and Lexiva® (fosamprenavir) are comparable to Kaletra® (lopinavir/ritonavir) as “preferred” protease inhibitor (PI) options for HIV-positive people starting therapy for the first time, according to new federal treatment guidelines issued by the U.S. Department of Health and Human Services (DHHS). The October 10th publication of the Guidelines for the Use of Antiretroviral Agents in HIV-1-infected Adults and Adolescents replace the last version published on May 4th and contain a number of notable revisions.

The treatment of HIV infection has improved steadily since combination therapy became the standard-of-care ten years ago. More recently, new drugs have been approved and research has been conducted to explore the uncharted potential of older medications. Such developments have helped to improve the effectiveness of HIV treatment, along with the added benefits of dosing simplification and improved side effect profiles.

To ensure that these research advances do not go unnoticed by busy healthcare providers involved in the management of HIV infection, the DHHS has long maintained an independent blue-ribbon group of HIV experts – the Panel on Antiretroviral Guidelines for Adults and Adolescents – to regularly come up with balanced and informative medical management guidelines. The Panel considers new evidence and adjusts recommendations accordingly. The primary areas of attention and revision have included when to initiate therapy, which drug combinations are preferred and which drugs or combinations should be avoided, and ways to utilize treatment to combat drug-resistant HIV.

Revisions to the guidelines are issued roughly once a year. While updates to previous versions of the guidelines are often minimal, some revisions – such as the most recent publication – reflect more substantive changes.

Of particular interest in the October 10th publication of theguidelines are major revisions to key tables summarizing therecommended HIV drugs for HIV-positive people beginning therapy for thefirst time.

For several years, the DHHS has designated select HIV drugs as “preferred” options, based on study results indicating powerful and long-lasting effectiveness, acceptable tolerability, and ease of use. “Alternative” HIV drug options are those that have been proven useful in clinical trials, but may have disadvantages, perhaps decreased effectiveness or more side effects when compared to a preferred option.

Shortly after it was approved in 2000, Kaletra – containing lopinavir plus a low boosting dose of ritonavir – was designated as the sole preferred PI option, based on its strong performance in clinical trials. Capitalizing on the ritonavir-boosting principle that contributed to Kaletra’s success, two other PIs were awarded the coveted preferred title in the most recent guidelines: Reyataz and Lexiva, both taken with low-dose Norvir to boost their effectiveness against HIV.

The promotion of Norvir-boosted Lexiva, from an alternative PI option in the May 2006 guidelines, was based largely on its comparable efficacy and side effects in the KLEAN study, a head-to-head comparison of Norvir-boosted Lexiva and Kaletra. While Reyataz combined with low-dose Norvir has not yet been compared to Kaletra in clinical trials involving HIV-positive people starting therapy for the first time, its efficacy as a boosted PI, once-daily dosing, and proven benefit in treatment-experienced patients has made it a reliable treatment option.

As for the other available PIs, both Viracept® (nelfinavir) and Norvir-boosted Invirase® (saquinavir) have been demoted. Once classified as alternative PI options, they are now listed as “possible” options – a new category listing specific HIV agents that can be used in first-time treatment regimens, but generally considered to be inferior to preferred or alternative options recommended by the DHHS. Crixivan® (indinavir), used with or without a Norvir boost, is classified as an HIV drug that simply shouldn’t be taken by those starting HIV treatment for the first time.

As for the selection of non-nucleoside reverse transcriptase inhibitors (NNRTIs), Sustiva® (efavirenz) remains the preferred choice. Viramune® (nevirapine) holds its place as the alternative NNRTI option, with Rescriptor® (delavirdine) listed as an inappropriate NNRTI for first-time treatment takers.

There are also a few notable revisions to the preferred and alternative nucleoside reverse transcriptase inhibitor (NRTI) listings, with emphasis now being placed on available fixed-dose combination (FDC) tablets. The FDCs Truvada® (containing tenofovir and emtricitabine) and Combivir® (zidovudine/lamivudine) are now preferred NRTIs for use in combination with NNRTIs and PIs; in the past these FDCs were not specified and tenofovir plus emtricitabine or Epivir® (lamivudine) was only preferred if used in combination with Sustiva. Another FDC, listed as an alternative option, is Epzicom® (abacavir/lamivudine).

The complete October 10th version of the DHHS treatment guidelines is available through the DHHS’s AIDSinfo website. Changes to the document are highlighted in yellow. A hardcopy version of the guidelines, shipped by mail, can also be requested through AIDSinfo.