SAN FRANCISCO – Those desperate for new treatments for Clostridium difficile infection may want to keep an eye on the experimental oral antibiotic cadazolid, which looked promising in an early-phase trial, according to Daniela Baldoni, Pharm.D.
Cadazolid is in the oxazolidinone class of antibiotics. Its mechanism of action consists mainly of bacterial protein-synthesis inhibition.
Cadazolid produced low systemic exposure with high concentrations at the desired site – the colon – and was well tolerated in 64 healthy men who received up to 3,000 mg b.i.d. for 10 days, she reported in a poster presentation at the conference. Dr. Baldoni is employed by Actelion Pharmaceuticals, the company that is developing cadazolid.
The study randomized nonsmoking men aged 45-60 years and a body mass index of 18-32 kg/m2 to single or multiple doses of cadazolid or placebo.
In the single-dose group, 30 fasting subjects received a single dose of 30, 100, 300, 1,000, or 3,000 mg cadazolid and 10 subjects received matching placebo. After a wash-out period of 8-15 days, the six subjects who had taken 300 mg received a second dose of 300 mg after eating instead of after fasting. In the multiple-dose group, 18 subjects took 300, 1,000, or 3,000 mg of cadazolid twice a day and 6 received matching placebo for 10 days.
Taking cadazolid with food appeared to increase the rate and extent of drug absorption by two- to fivefold. Blood samples showed low systemic exposure after single or multiple doses, with a minor, twofold increase in cadazolid in plasma after 10 days for all doses in the twice-a-day group, Dr. Baldoni reported at the meeting, sponsored by the American Society for Microbiology.
The dose or duration of treatment did not seem to affect the number of adverse events (none of which were serious). They occurred in 27%-39% of cadazolid-treated subjects and in 17%-40% taking placebo and were mostly headache or diarrhea.
All subjects completed the study except one man in the 100-mg single-dose subgroup who withdrew consent for reasons unrelated to adverse events.
