The following items were disclosed at the International AIDS Society conference held July 22-25 in Sydney, Australia:
• Boehringer Ingelheim GmbH, of Ingelheim, Germany, presented new data from two new studies of Viramune, the first drug approved from the non-nucleoside reverse transcriptase inhibitor class. Results from an extended three-year follow-up analysis of the 2NN study demonstrated that HIV-positive patients taking Viramune (nevirapine) achieved a comparable virologic and immunologic response to patients taking efavirenz. The second study, NILE, examined the mechanism by which Viramune increases the level of high-density lipoprotein cholesterol, reconfirming that Viramune increases HDL cholesterol through 24 weeks. BI recently initiated the ArTEN trial, which will compare the efficacy and safety of Viramune dosed once or twice daily vs. atazanavir boosted with ritonavir in antiretroviral-naive HIV patients.
• GlaxoSmithKline plc, of London, said a new study comparing two protease inhibitors used in the treatment of HIV patients showed similar efficacy and lipid effects. The head-to-head study evaluated the use of GSK's approved agent Lexiva, developed with Cambridge, Mass.-based Vertex Pharmaceuticals Inc., vs. atazanavir (Reyataz, Bristol-Myers Squibb Co.). The randomized, open-label study in 106 patients compared efficacy and safety of the drugs, each in combination with tenofovir and emtricitabine. GSK said at 48 weeks, both treatment arms showed comparable viral suppression, changes in lipid levels, incidence of adverse effects and CD-4 cell count improvements. A separate study, also presented at the conference, provided additional information on the efficacy and impact on lipids of Lexiva with a lower dose of ritonavir in treatment-naive patients.
• Monogram Biosciences Inc., of South San Francisco, said collaborator Pfizer Inc., of New York, reported results of a Phase III MERIT trial of maraviroc for treatment-naive adult patients infected with CCR5-tropic HIV-1. Rates of virologic suppression in patients receiving Pfizer's CCR5 antagonist compared to efavirenz were 70.6 percent vs. 73.1 percent for less than 400 copies/ml, and 65.3 percent vs. 69.3 percent at less than 50 copies/ml in the full analysis set study population (n=360, maraviroc/n=361, efavirenz). Reduced adverse events were seen in the maraviroc arm. Pfizer already has received an approvable letter from the FDA for use of maraviroc in treatment-experienced patients. Monogram's Trofile Assay has been used to select patients for the clinical trials of the drug.
• Panacos Pharmaceuticals Inc., of Watertown, Mass., said its programs were the subject of five poster presentations. A safety analysis of the inhibitor bevirimat (PA-457), Panacos' lead HIV drug candidate, showed the HIV-1 maturation inhibitor was well tolerated and produced no clinically relevant laboratory test abnormalities. Another study concluded that co-administration of bevirimat with ritonavir was well tolerated and that bevirimat did not impact the pharmacokinetics of ritonavir. A third update was on Panacos' HIV fusion inhibitor program. It outlined the identification of three structurally distinct series of drug-like small molecules, which inhibit HIV fusion at a different site than the approved HIV fusion inhibitor Fuzeon.
• Polydex Pharmaceuticals Ltd., of Toronto, reported further analysis from the Phase III trial of Ushercell, a potential microbicide also known as cellulose sulfate. That CONRAD trial was halted in January due to possible issues related to women who tested positive for HIV during the course of the trials. The latest analysis showed there were more seroconversions in the Ushercell group than the placebo group, but not at a statistically significant level. Out of 1,425 women who were enrolled in the trial, 41 seroconverted: 25 using Ushercell and 16 using the placebo gel. The company plans to study the cause of those seroconversions, and to move forward in developing the product as a contraceptive.
• Progenics Pharmaceuticals Inc., of Tarrytown, N.Y., presented new findings from a Phase Ib trial of PRO 140 in HIV patients. In May, Progenics announced positive results from the study, showing dose-dependent and statistically significant viral load reductions. The new data included detailed kinetics of the antiviral effects of the CCR5 humanized monoclonal antibody. The company also reported positive preclinical findings for a subcutaneous form of PRO 140, which will be advanced into clinical trials later this year.