The following is a summary of data from the 47th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), which is being held through today in Chicago.

• Ardea Biosciences Inc., of Carlsbad, Calif., said results from two Phase I studies of RDEA806, an HIV non-nucleoside reverse transcriptase inhibitor, demonstrated the drug was safe and well tolerated at all doses evaluated, with no serious adverse events or clinically significant or ECG abnormalities. The studies involved 92 healthy adult male volunteers, dosed for up to 14 days at up to 1,000 mg/day. The systemic exposure of RDEA806 increased linearly from 50 mg to 600 mg under fasted or fed conditions, and the terminal half-life of the drug was up to 11 hours after single doses and up to 13 hours following multiple doses. The company reported additional drug-drug interaction liability data showing that, in vitro and in vivo, RDEA806 appeared unlikely to be an inducer or inhibitor of major P450 enzymes or be affected by CYP3A4.

• Arpida Ltd., of Basel, Switzerland, reported data from its first Phase III study showing that its antibiotic, iclaprim, demonstrated high microbiological eradication rates against major complicated skin and skin structure infection pathogens, comparable with linezolid. Eradication rates for methicillin-resistant Staphylococcus aureus were 84.7 percent and 85.3 percent, respectively. Results from additional studies showed that the drug was active against community-acquired and nosocomial staph infections, and exhibited rapid bactericidal activity against several clones of MRSA.

• Cel-Sci Corp., of Vienna, Va., reported that its CEL-1000 immunomodulator was shown in a mouse model to be able to jump-start the immune response against the recombinant hepatitis B virus protein more quickly than other vaccine adjuvants. The effect was seen within 14 days, and resulted in up to a 40 percent increase in antibody signal at day 28. CEL-1000, derived from the beta chain of human MHC-II, is a modified version of a human immune-based protein known to bind to both human and mouse immune cells and appears to act by enhancing the host's protective immune response.

• Dynavax Technologies Corp., of Berkeley, Calif., reported that the seroprotection of Heplisav at 50 weeks after the first vaccination remained at 100 percent, while Engerix-B, a competitor vaccine marketed by London-based GlaxoSmithKline plc, declined in seroprotection. Data from the 400-patient Phase III trial showed that after three doses, Heplisav provided seroprotection, meaning anti-HBsAg antibodies greater than or equal to 10 mIU/mL, to all subjects vs. 68.6 percent for those treated with Engerix-B. Dynavax plans a biologics license application submission for Heplisav in 2008.

• FermaVir Pharmaceuticals Inc., of New York, and academic collaborators from the Rega Institute for Medical Research and Cardiff University reported preclinical data for FV-100, an oral, bicyclic nucleoside analogue for herpes zoster infections. Data demonstrated favorable antiviral and pharmacokinetic properties, including the compound's bioavailability and activity against varicella zoster virus. Results also showed that the active component of FV-100 required only a two-hour exposure time on infected cells, compared to one day and three days for brivudin and acyclovir, respectively, to completely exert anti-VZV activity.

• GlaxoSmithKline plc, of London, said new study results indicated that Rotarix, an oral candidate vaccine to prevent rotavirus gastroenteritis in infants, could be co-administered with routine infant vaccines recommended in the U.S. at the two- and four-month immunization visits, pending FDA approval. Data from a Phase III study showed that co-administration does not impair the immune responses to vaccines included in the schedule of recommended immunizations. GSK licensed rights to Rotarix from Needham, Mass.-based Avant Immunotherapeutics Inc.

• Iomai Corp., of Gaithersburg, Md., said study data showed that travelers to Mexico and Guatemala who received the company's patch-based travelers' diarrhea vaccine were significantly less likely to be sickened as compared with those who received placebo. The study met its primary endpoint and showed that, of the 59 subjects who received Iomai's patch, only three suffered moderate or severe diarrhea, compared to 23 of the 111 who received placebo, representing a 75 percent reduction. The company plans to begin a Phase III program for the patch vaccine in 2008.

• MethylGene Inc., of Montreal, reported preclinical results showing that its histone deacetylase (HDAC) inhibitor, MGCD290, appeared to have synergistic in vitro activity against human fungal clinical isolates of Candida and Aspergillus species when administered with the antifungal agents voriconazole, fluconazole and itraconazole. It demonstrated synergy against 37 of the 45 (82 percent) isolates of Candida when combined with voriconazole and 34 of 45 (76 percent) when combined with fluconazole. Of the 16 Aspergillus species tested, MGCD290 demonstrated synergy with both voriconazole and itraconazole against 11 isolates.

• Monogram Biosciences Inc., of South San Francisco, reported data showing the superior ability of its Trofile assay to identify HIV patients who are most likely to respond to co-receptor inhibitors, compared to genotypic approaches. The company also reported technical advances that will allow improvements for a tenfold increase in Trofile's ability to identify patients with virus populations that harbor rare variants that are unlikely to be inhibited by specific drugs in the co-receptor inhibitor class. Trofile is a cell-based infectivity assay for determining whether HIV is able to gain entry into cells via the CCR5 or CXCR4 co-receptor, or both.

• Replidyne Inc., of Louisville, Colo., reported preclinical data showing that REP3123, a narrow-spectrum antibacterial agent, stopped the production of intestinal toxins caused by Clostridium difficile bacteria. Data suggested that the drug inhibits growth and blocks the production of those toxins to potentially reduce the severity of or even prevent C. difficile-associated disease. Preclinical data also showed that REP3123 inhibits growth and prevents spore forming of the C. difficile bacterium without inhibiting other key organisms that are essential for normal intestinal functioning.

• Targanta Therapeutics Corp., of Cambridge, Mass., reported in vitro data from its lead antibiotic drug candidate, oritavancin, showing the drug was more active than either metronidazole or vancomycin against Clostridium difficile bacteria. Oritavancin also was more active than vancomycin against 94 percent of the C. difficile strains tested by the broth macrodilution method. A separate in vitro study showed that oritavancin interacts with and disrupts the transition from dormant C. difficile spores to vegetative cells to a greater extent than existing antimicrobial agents. Additional in vitro studies demonstrated the drug's activity against Staphylococcus aureus infections. Oritavancin is a semi-synthetic lipoglycopeptide antibiotic candidate that successfully completed Phase III testing in Gram-positive complicated skin and skin structure infections.

• Theravance Inc., of South San Francisco, and Astellas Pharma US Inc., of Deerfield, Ill., said Phase III results of telavancin in the 200-patient subset of surgical-site-associated, Gram-positive complicated skin and skin structure infections (cSSSI) showed that the telavancin-treated patients had higher clinical cure, bacterial eradication and overall response rates than those given vancomycin. The product is under review by regulatory authorities in the U.S. and Europe in cSSSIs and is in Phase III testing in hospital-acquired pneumonia.