ActivBiotics Announces Completion Of Patient Enrollment In Phase III Clinical Trial In Peripheral Arterial Disease

LEXINGTON, Mass., Sept. 26 /PRNewswire/ -- ActivBiotics, Inc. today announced that it has completed enrollment in PROVIDENCE-1, the first of two planned Phase III clinical trials designed to study the effect of Rifalazil in the treatment of intermittent claudication associated with peripheral arterial disease or PAD. The double-blind, randomized, placebo-controlled trial will evaluate the efficacy and safety of Rifalazil in approximately 274 patients in the United States, Russia and Brazil. The FDA has granted Fast Track designation for the development of Rifalazil for this indication.

PROVIDENCE-1 (Prospective Evaluation of Rifalazil Effect on Vascular Symptoms of Intermittent Claudication and Other Endpoints in Chlamydia Seropositive Patients) is designed to study the effect of Rifalazil in the treatment of intermittent claudication associated with PAD.

"We are extremely pleased with the timely completion of patient enrollment for PROVIDENCE-1 and we are looking forward to reporting our results in the second half of 2007," stated Steven C. Gilman, Ph.D., President and Chief Executive Officer. "We appreciate the hard work and dedication of our clinical development team, the investigators and the research coordinators, as well as the support we received from our steering committee."

About ActivBiotics, Inc.

ActivBiotics, Inc. is a biopharmaceutical company focused on the discovery, development and commercialization of therapies for the treatment of inflammatory diseases and bacterial infections. For more information on ActivBiotics, Inc., please visit our web site at: http://www.activbiotics.com.

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This press release may contain or incorporate by reference certain statements that are not historical facts, including statements preceded by, followed by or that include the words "may," "believes," "will", "expects," "anticipates" or the negation thereof, or similar expressions, which constitute "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 (the "Reform Act"). All statements that address events, transactions or developments that are expected or anticipated to occur in the future are forward-looking statements within the meaning of the Reform Act. Such forward-looking statements involve risks, uncertainties and other factors that may cause the actual performance or achievements of ActivBiotics, Inc. to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. For those statements, ActivBiotics, Inc. claims the protection of the safe harbor for forward-looking statements contained in the Reform Act. ActivBiotics, Inc. will not undertake and specifically declines any obligation to publicly release the result of any revisions that may be made to any forward-looking statements to reflect events or circumstances after the date of such statements or to reflect the occurrence of anticipated or unanticipated events.

CONTACT: Glenn Kazo, Chief Business Officer, +1-781-372-4864,gkazo@activbiotics.com, or Christina DiCarlo, Manager, CorporateCommunications, +1-781-372-4807, cdicarlo@activbiotics.com, both ofActivBiotics, Inc.

Web site: http://www.activbiotics.com//