By Mary Welch

Interim results in a Phase II trial of Synsorb Cd for recurrent Clostridium difficle associated diarrhea (CDAD) were so statistically impressive that Synsorb Biotech Inc. stopped the trial and will start a Phase III trial within the next six to nine months.

"They were the most phenomenal results," said David Cox, Synsorb's president and CEO. "I believe we could even use the 'breakthrough' word."

The Calgary, Alberta, company reported on 103 patients, all of whom had already suffered one recurrence of CDAD, a common disease that can affect people undergoing antibiotic therapy, hospitalized patients or those other-wise immunocompromised. The trial was expected to enroll 375 patients. Some 3.5 million North Americans are afflicted annually and it is not uncommon for the disease to recur even after it has been successfully treated.

Synsorb Cd is designed to remove the bacterial toxin that causes the symptoms of CDAD.

In the study, all patients were given the antibiotic metronidazole, the first-line treatment, for 10 days and were randomized to receive either placebo, a low dose (8 grams per day) or a high dose (16 grams per day) of Synsorb Cd. The carbohydrate-based drug was administered orally in a powder form.

Patients received Synsorb Cd from days one through 25 and were monitored for 67 days. The trial's endpoint was a 50 percent reduction in recurrence. Of the 103 patients enrolled in the trial, the rate of recurrence was 48.3 percent in placebo patients, 31.6 percent for those getting the low dose, and 9.1 percent for those taking the high dose.

For those patients who completed an adequate course of metronidazole for 10 days, as co-therapy to Synsorb Cd, the recurrence rate was 63.6 percent in those receiving placebo, 48 percent for those on the low dose and 13 percent for those receiving the high dose.

"It's the same study but a different way of looking at the data," Cox said of the two results. "In the second case, it involved about 70 patients from the 103. Those 30 patients or so dropped out of the trial for various reasons, either they got better, withdrew consent - whatever. It's a more structured way of looking at the data. The point is that either trial shows results that are just so statistically compelling that there was no sense carrying on the trial."

Cox envisions that two Phase III trials will start within six to nine months and will involve between 400 and 500 patients. One trial will take place in North America, the second possibly in Europe. The higher dose will be used.

"Because the data was so compelling, there is a probability of a power trial with relatively small numbers," Cox said.

In other news, the company decided not to start a small supplementary trial of Synsorb Pk in treating verotoxigenic Escherichia coli (VTEC) gastroenteritis (diarrhea). Synsorb had considered doing this supplemental trial while the main Phase III trial for hemolytic uremic syndrome (HUS) is ongoing.

"In talking with the FDA they said we could do the short trial but that before starting, we should look at the ongoing trial's data on diarrhea and see if there were any evidence that Synsorb Pk helped," Cox said. "The FDA also said that this mini-trial would not be sufficient to support an NDA [new drug application] filing and should be supported by further evidence. We did that - looked back at the data - and could find no corraborative evidence."

Not starting the mini-trial does not reflect upon the drug's possible results with the larger, more important indication, Cox said. "What we had hoped was that by completing a quick trial we could have filed for an accelerated NDA on this minor indication as early as the first quarter of next year. As a result, we won't be doing that, and in fact several potential partners were concerned that if Synsorb Pk were approved for the diarrhea indication before the prevention of HUS indication it would compromise the drug's pricing.

"So we anticipate releasing data on the Phase III trial in December and filing for the larger indication later."

Synsorb's stock (NASDAQ:SYBB) closed Monday at $2.187, down 18.75 cents.

Cox was surprised that the stock didn't reflect the company's Phase II results.

"We were a company with one Phase III drug and one Phase II drug," he said. "Now we are a company with two Phase III drugs. It's a complex story but I think once the investment market understands it, they'll wake up. Right now it looks like selling into strength."