The following items were released from the International AIDS Society conference held July 22-25 in Sydney, Australia:

• Boehringer Ingelheim GmbH, of Ingelheim, Germany, said it will begin enrolling patients next month in its POTENT (PrOspecTive EvaluatioN of Tipranavir vs. Darunavir in Treatment-Experienced Patients) study to compare Aptivus (tipranavir) vs. darunavir (Prezista), both with ritonavir as part of combination antiretroviral therapy. The study is expected to include 800 patients, with the primary endpoint of time to virologic failure and a secondary endpoint of virologic response at 48 weeks of treatment. The company said the POTENT study is the first head-to-head study comparing Aptivus, a nonpeptidic protease inhibitor, to another protease inhibitor developed specifically for treatment-experienced patients with HIV resistance to multiple agents in the protease inhibitor class.

• Incyte Corp., of Wilmington, Del., said results from a 14-day Phase IIa study demonstrated that INCB9471 provided a significant decline in viral load when used as a monotherapy in 19 HIV-infected patients, comprised of 10 treatment-naïve patients and nine treatment-experienced patients currently not on antiviral therapies. Patients receiving the drug achieved a mean 1.72 log10 viral load drop at day 14, and the nadir in mean viral load decline was 1.81 log10 and occurred at day 16. Two weeks after their last dose, patients continued to show evidence of viral suppression with a mean 0.81 log10 reduction relative to baseline. INCB9471 is an oral CCR5 antagonist designed to block the virus from entering uninfected cells.

• Merck & Co. Inc., of Whitehouse Station, N.J., reported results from an ongoing 198-patient Phase II study of Isentress (raltegravir), an investigational oral HIV integrase inhibitor, in combination with tenofovir (Viread, Gilead Sciences Inc.) and lamivudine (Epivir, GlaxoSmithKline plc) showing that Isentress provided reductions in HIV RNA to undetectable levels of less than 50 copies/mL (83 percent to 88 percent of patients), which was comparable to efavirenz (Sustiva, Bristol-Myers Squibb Co.) combined with the same agents (87 percent of patients). Those results were observed with all four doses studies, ranging from 100 mg to 600 mg twice daily, in treatment-naïve HIV patients. Isentress showed minimal impact on total and low-density lipoprotein serum cholesterol, serum triglycerides and the ratio of total cholesterol to HDL cholesterol.

• Schering-Plough Corp., of Kenilworth, N.J., said results from a 118-patient Phase II trial showed vicriviroc, its investigational CCR5 antagonist, demonstrated potent and sustained viral suppression through 48 weeks of therapy in treatment-experienced HIV patients when administered in once-daily doses in combination with an optimized ritonavir-boosted protease inhibitor-containing antiretroviral regimen. Patients in the 10 mg and 15 mg treatment groups achieved a median decrease in viral load of 1.92 log10 and 1.44 log10 and a median increase in CD4 cell count of 130 and 96 from baseline, respectively. More patients in the vicriviroc groups had undetectable virus at 48 weeks compared to those in the placebo group. Vicriviroc is an extracellular inhibitor of HIV infection designed to block entry of infectious virions into uninfected CD4 cells via antagonist of the CCR5 co-receptor.

• Starpharma Holdings Ltd., of Melbourne, Australia, reported results showing that VivaGel (3 percent SPL7013 gel) was well-tolerated in men when applied topically once daily for seven days and left in place for nine hours. As seen in a previous completed trial in women, there was no evidence of absorption of the active ingredient into the blood after topical application. The company said those data indicated that VivaGel is suitable for further development as a topical microbicide for the prevention of HIV and genital herpes.