HIV Treatment Clinical Study Results Presented at European AIDS Conference

The results of several clinical studies of AIDS drugs were presented this week at the European AIDS Clinical Society's 8th European Conference on Clinical Aspects and Treatment of HIV Infection in Athens, Greece. Study findings include those listed below:

• Atazanavir: Bristol-Myers Squibb announced that its protease inhibitor atazanavir, an experimental once-a-day drug currently in Phase III clinical trials, controls HIV without highly elevating blood fat levels. In the study of 467 patients, those receiving atazanavir experienced a "clinically insignificant 5%-6% increase in cholesterol levels," compared to 25% for those taking twice-a-day nelfinavir in combination with stavudine and lamivudine (Reuters, 10/29). Further, 74% of patients who took atazanavir had an HIV RNA level of less than 400 copies/mL at the end of 48 weeks, compared to 60% of those taking the nelfinavir combination (Bristol Myers-Squibb release, 10/29).
• Efavirenz: Bristol-Myers Squibb reported that treatment-naive patients taking combination therapy that included its once-daily non-nucleoside reverse transcriptase inhibitor efavirenz, sold under the brand name Sustiva, had lower rates of treatment failure -- defined as a viral load greater than 400 copies/mL -- than those taking regimens that included nevirapine. A study of 1,078 patients (555 patients on combination therapy including efavirenz; 523 patients on combination therapy including nevirapine) showed that 37.1% of patients taking efavirenz experienced treatment failure versus 59.4% of patients taking nevirapine. After one year of treatment, 51% of patients taking efavirenz maintained a viral load of less than 400 copies/mL compared to 45% of patients receiving nevirapine (Bristol Myers-Squibb release, 10/29). Another study presented by Bristol Myers-Squibb showed that patients who switch to efavirenz from a protease inhibitor-containing regimen maintain viral load levels below 400 copies/mL longer than those who do not switch (Bristol Myers-Squibb release, 10/29).
• Emtricitabine: Bristol-Myers Squibb presented data showing that a once-daily protease inhibitor sparing regimen of efavirenz, didanosine and the investigational new drug emtricitabine, or FTC, suppressed HIV viral load levels in 40 treatment-naive patients through 96 weeks. The single-arm pilot study showed that 85% of patients achieved and maintained a viral load below 400 copies/mL after 96 weeks of treatment, with 80% maintaining a viral load less than 50 copies/mL (Bristol-Myers Squibb release, 10/29).
• Nevirapine: Boehringer Ingelheim presented two studies of its non-nucleoside reverse transcriptase inhibitor nevirapine, sold under the brand name Viramune, that showed the drug improved patients' lipoprotein profile when taking as part of a regimen. Patients taking nevirapine experienced a 40% increase in HDL cholesterol and a reduction in the total cholesterol/HDL-cholesterol ratio after 96 weeks. Patients taking the protease inhibitor indinavir experienced increases in total and LDL-cholesterol, as well as an increase in the total/HDL-cholesterol ratio (Boehringer Ingelheim release, 10/29).
• Saquinavir: Roche presented study results showing that a once-daily regimen of its protease inhibitor saquinavir, marketed under the brand name Fortovase, administered with a "mini-dose" of ritonavir to patients co-infected with HIV and hepatitis C who received methadone helped "simplify the HIV treatment schedule." Nearly 90% of the 18 HIV-positive patients on methadone who received saquinavir plus ritonavir for an average of 10 months achieved a viral load under 400 copies/mL, and 44% achieved viral loads under 50 copies/mL. In a comparison group of five HIV-positive patients who received indinavir, 80% achieved a viral load under 400 copies/mL and two patients achieved a viral load under 50 copies/mL (Roche release, 10/29).
• Stavudine: Bristol-Myers Squibb presented a study that showed a new once-daily extended release stavudine can be safely and effectively used in combination highly active antiretroviral therapy. In the study of 150 patients, 78% of those who took the extended release stavudine achieved viral loads of less than 400 copies/mL in 48 weeks, compared to 67% of patients who took the older twice-daily stavudine (Bristol-Myers Squibb release, 10/31).
• TMC125: Tibotec-Virco revealed that its non-nucleoside reverse transcriptase inhibitor TMC125 reduced the HIV viral load in 12 patients by an average of 99% in one week. Eight of the 12 subjects experienced a viral load reduction to less than 400 copies/mL, and viral load in two patients fell to less than 50 copies/mL (Tibotec-Virco release, 10/29).
• T-20 and T-1249: Roche and Trimeris presented a study showing that the fusion inhibitors T-20 and T-1249 fight HIV infection by "completely blocking the ability of HIV to enter the host cell," a new approach to combating the virus. T-20 lowered viral load tenfold in 56% of study participants, with about 39% of patients attaining viral loads below 400 copies/mL. Tests of T-1249 are less advanced, but "promising." The drugs may be an effective alternative for patients who have developed resistance to other AIDS drugs and have limited treatment options (BBC News, 10/31).