ActivBiotics announces disappointing results for PAD drug

LEXINGTON, Mass. ActivBiotics recently announced the results of its Providence-1 clinical trial, which evaluated the effect of rifalazil in the treatment of intermittent claudication, associated with peripheral arterial disease, at the Scientific Session at the American Heart Association’s 2007 annual meeting.

The results showed that treatment for two months with the experimental antibiotic rifalazil did not result in a significant improvement in walking distance, claudication onset times, or other clinically-relevant parameters of PAD.

The study enrolled 297 consenting men and women (40-80 years old) with diagnosis of intermittent claudication due to PAD who also had high levels of antibodies to C. pneumonia. Chlamydia pneumonia infection of the vascular system has long been thought to play a role in accelerating the course of vascular disease potentially by increasing inflammation in the arterial wall thus leading to exacerbation of atherosclerosis, which could reduce blood supply to target limbs and organs.

“We are clearly disappointed with the low efficacy signal seen in rifalazil-treated patients which was only 4 percent greater than placebo, a difference which was not statistically significant. On the other hand, we are pleased that the population demographics, low placebo response and overall low variability in this study provided a very clear cut answer,” said Steven Gilman, chairman and chief executive officer of ActivBiotics.