HIV Health News October 2006

One-Pill, Once-Daily HAART Regimen

On July 12, the Food and Drug Administration (FDA) announced the approval of Atripla, the first single-pill, once-daily antiretroviral regimen to treat HIV infection. The fixed-dose pill combines Gilead's tenofovir (Viread) and emtricitabine (Emtriva)--already available together as Truvada--with Bristol-Myers Squibb's efavirenz (Sustiva).

The co-formulation was approved for both treatment-naive and treatment-experienced individuals. It can be taken alone or in combination with other anti-HIV drugs. The convenience of this simplified regimen may substantially impact adherence to HIV treatment--increasing control of the virus and of disease progression.

Atripla is the first multi-class antiretroviral co-formulation available in the United States and marks the first joint venture by two U.S. pharmaceutical companies to combine their patented anti-HIV drugs in a single product.

Darunavir for Adults with PI-Resistant HIV

Tibotec's protease inhibitor (PI), darunavir, formerly known as TMC114, received approval from the FDA on June 23. The new drug, marketed as Prezista, was approved for treatment-experienced individuals with HIV resistant to treatment with PIs. It must be taken with a low dose of ritonavir (Norvir).

At the 16th International AIDS Conference, held in August, researchers presented data from studies pitting ritonavir-boosted darunavir against other PIs in treatment­experienced individuals. The new drug was easily tolerated and showed sustained and superior virological suppression, even in participants with PI-resistant HIV. Darunavir appears to represent a strong new option for individuals on failing antiretroviral regimens.

Integrase Inhibitor Progresses in the Pipeline

Also presented at the conference were results from a clinical trial of MK-0518, Merck's experimental integrase inhibitor. In this Phase II dose-ranging study, 198 treatment-naive participants received tenofovir and lamivudine (Epivir), plus either 600 mg efavirenz (Sustiva) or 100 mg--600 mg MK-0518. Viral load reductions were similar among all participants. However, those taking the integrase inhibitor achieved viral loads of less than 50 copies/mL more rapidly than did those receiving efavirenz.

Integrase inhibitors represent an entirely new class of antiretroviral drugs--good news for individuals who have failed on currently available classes of HIV medications. MK-0518 is the most advanced candidate in this new class, with Phase III trials underway.

Merck announced on August 17 that a global expanded access program will make the experimental drug available to people who are unable to participate in clinical trials. Enrollment in the program is expected to begin within the next few months.