By Mary Welch

Synsorb Biotech Inc. enrolled its first patient in a Phase III trial of Synsorb Cd, which is designed to prevent recurrent Clostridium difficile antibiotic-associated diarrhea (CDAD).

The company, based in Calgary, Alberta, is conducting two identical Phase III trials, each with 60 sites. The first will take place only in the U.S.; the second will have sites in the U.S., Canada and possibly Europe. About 450 patients will be involved. Two different doses ¿ 16g per day and 24g per day ¿ will be co-administered with metronidazole and tested against a placebo. An antibiotic, metronidazole is the first-line treatment for the condition.

The primary endpoint is a clinically significant reduction in the rate of recurrent CDAD.

¿There is no specific percentage of outcome,¿ said David Cox, the company¿s president and CEO. ¿There is no treatment for this, so it¿s not really a matter of 40 percent or 60 percent. It¿s a statistically significant difference between the placebo and Synsorb Cd.¿

Among the criteria to be judged are the occurrence and frequency of diarrhea and the presence of the Clostridium difficule antigen in the stool, along with toxin A.

The company anticipates the trial will be completed within 24 months and a new drug application (NDA) filed in 2002.

Recurrent CDAD is a common hospital-acquired infection, usually associated with antibiotic use, AIDS and chemotherapy. The most severe form affects more than 800,000 patients per year worldwide.

Interim results from a Phase II trial of Synsorb Cd were so statistically impressive that Synsorb stopped the trial in order to proceed to the Phase III stage. (See BioWorld Today, Sept. 14, 1999, p. 1.)

This is the second drug Synsorb has in pivotal trials. Synsorb Pk is ¿well into its Phase III trials with more than 500 patients enrolled,¿ Cox said. Synsorb Pk is being tested to prevent the progression to hemolytic uremic syndrome in children who have contracted verotoxigenic Escherichia coli infections.

¿We¿ll have the interim results at the end of the second quarter, in which case we either file the NDA, stop the trial completely or recognize a trend but keep on with the trial,¿ he said

Both drugs are partnered in Canada, and Synsorb Pk also has marketing deals for Japan, Holland, Belgium and Luxembourg. ¿Pharmaceutical companies are waiting for the interim trials before really getting into serious discussions with us, and I don¿t blame them,¿ Cox said.

However, the company is in mid- to late-stage negotiations with at least two pharmaceutical companies over the marketing rights to Synsorb Cd, he said. ¿We can expect to make an announcement by the end of the year.¿

With its two drugs in Phase III trials, Synsorb is experiencing the corporate version of ¿empty nest syndrome.¿

¿Over the last years we have systematically and deliberately developed a focus on getting these products across the finish line, and in doing so, we have divested ourselves of all outside interests that we had a toe in,¿ Cox said. ¿We have done nothing but focus, focus, focus. We are interested now in acquisitions as a strategy, as well as internal research and development efforts. We are already embarking on a course of identifying products and companies that will fill in the gaps of our pipeline.¿

Synsorb¿s stock (NASDAQ:SYBB) closed unchanged Monday at $5.