The following data were presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in San Francisco.

• PolyMedix Inc., of Radnor, Pa., presented data on its defensin-mimetic antimicrobial compounds, including results of the first Phase II study of lead compound, brilacidin (PMX-30063). In the study, 215 patients with acute bacterial skin and skin structure infections (abSSSI) and evidence of Staphylococcus aureus were randomized into three treatment groups and given a low (0.40 mg/kg day 1 + 0.30 mg/kg days 2-5), medium (0.75 mg/kg day 1 + 0.35 mg/kg days 2-5) or high (1.0 mg/kg day 1 + 0.35 mg/kg days 2-5) dose of brilacidin for five days followed by two days of placebo, or Cubicin (daptomycin, Cubist Pharmaceuticals Inc.) for seven days. Clinical response rates were high across all treatment groups and similar to daptomycin. Brilacidin was safely administered and adverse events appeared to be exposure-related, with overall adverse event rates under 10 percent in each dose group.

• Rib-X Pharmaceuticals Inc., of New Haven, Conn., reported positive findings from a Phase I intravenous (I.V.) dosing study in healthy subjects and an in vivo long-term safety study vs. linezolid for its next-generation oxazolidinone, radezolid. In addition, third-party presentations highlighted radezolid as a promising next-generation oxazolidinone with a favorable long-term safety profile, I.V. and oral dosing potential and potent activity against multiple Zyvox- (linezolid, Pfizer Inc.) resistant Gram-positive strains. In the Phase I dosing study, I.V. radezolid administered once daily for up to 14 days was well tolerated and approximately dose proportional in single or multiple daily doses up to 14 days. The three-month in vivo toxicology study showed radezolid to be well tolerated at all dose levels. Separately, the company presented efficacy and safety findings from its Phase IIb study of delafloxacin in acute bacterial skin and skin structure infections (abSSSI), including those caused by methicillin- and quinolone- resistant Staphylococcus aureus. As initially reported in December 2011, delafloxacin met or exceeded primary and secondary efficacy endpoints evaluated in comparison to linezolid, with and without aztreonam, and vancomycin, with and without aztreonam, including endpoints based on the new draft guidance from the FDA on abSSSI.

• Trius Therapeutics Inc., of San Diego, reported detailed findings from ESTABLISH 1, its first Phase III study of tedizolid phosphate in acute bacterial skin and skin structure infections. Results for the first of two registration studies showed tedizolid achieved primary and secondary efficacy outcomes after a short course of therapy and suggested improvements in key safety and tolerability measurements in the study population vs. comparator Zyvox (linezolid, Pfizer Inc.). In a late-breaking poster session, Trius also presented early stage tedizolid data from two Phase I crossover studies and from an animal study, demonstrating tedizolid does not appear to interact with monoamine oxidase type A.