Genzyme diarrhea drug fails in phase 3

CAMBRIDGE, Mass., July 6 (UPI) -- U.S. biotech firm Genzyme said Friday its tolevamer liquid failed in phase 3 to beat vancomycin in patients with C. difficile-associated diarrhea.

The company said the investigational liquid therapy being tested in more than 1,100 patients failed to meet its primary endpoint of non-inferiority to the standard oral dose of the antibiotic vancomycin, as measured by the percent of patients with resolution of CDAD.

Genzyme said these findings directly contradict its earlier phase 2 study of tolevamer in a solid oral dosage formulation, which successfully demonstrated non-inferiority to vancomycin.

"These are disappointing results that alter our expectations about the potential for commercializing tolevamer in the near future," said Henri Termeer, chairman and CEO of Genzyme. "The results of our second Phase 3 study will be available later this year and will help us determine what contribution tolevamer might be able to make in addressing this serious unmet medical need."

Genzyme noted that, in the phase 3 study, high rates of CDAD recurrences were seen in patients treated with either vancomycin or metronidazole but were not observed in patients treated with tolevamer liquid.

The treatment was generally well tolerated with no unanticipated safety issues, the company added.

Genzyme said it would present the results of its first phase 3 study -- which took place at about 300 sites in North America, Europe and Australia -- at an upcoming medical conference.

C. difficile usually takes hold in the colon when the use of broad-spectrum antibiotics has killed off the normal bacterial flora that typically reside there. The bacteria then produce toxins that disrupt the intestinal lining, causing cell death and inflammation that result in diarrhea and colitis.