By Mary Welch

Cell Pathways Inc. said Prevatac (exisulind), its compound for adenomatous polyposis coli (APC), did not achieve statistical significance in a Phase III study, forcing the company to delay filing a new drug application (NDA).

Robert Towarnicki, CEO of Horsham, Pa.-based Cell Pathways, told BioWorld Today he was "surprised" by the data, which the company discovered to be "totally inconsistent with previous data, both clinical and preclinical. We saw unexpected responses in the placebo that hurt statistical significance. It didn't make sense."

Cell Pathways' stock (NASDAQ:CLPA) plummeted 66 percent to close Tuesday at $9, down $18.25.

Towarnicki said it will take at least at month to go over the data, checking quality control as well as distribution issues. After that, the company will decide what to do next.

"We have not given up on the APC indication," Towarnicki said. "We have about four theories, but I don't want to speculate. I don't expect it to be the drug."

But he did not hold out hope the company can "salvage anything from this trial." If Cell Pathways goes ahead with the APC indication, filing an NDA could take another year to 18 months, he added.

Interim Data From Prostate Cancer Trial Due Soon

Prevatac, designed to cause apoptosis (programmed cell death) in cancerous and precancerous cells, inhibits a cyclic GMP phosphodiesterase and cell growth, without inhibiting COX pathways.

Cell Pathways hopes to generate more data, as soon as possible, that will validate the drug, Towarnicki said. Interim data are expected in March or April from a Phase II/III prostate-cancer trial with the compound. The double-blind, placebo-controlled study enrolled 90 patients, whose prostate specific antigen levels were rising following radical prostatectomy, indicating heightened risk of metastatic disease. If Prevatac succeeds in slowing or halting the spread of prostate cancer, the need for hormonal treatments will be delayed or eliminated, thus allowing men to retain their post-surgical sexual function.

Cell Pathways intended to conduct three more trials for prostate cancer.

"We have no plan, as yet, on how the prostate-cancer indication could get us [to FDA approval]," Towarnicki said. "We have to look at the other studies we had planned."

The company has an open-label Phase II trial with nine patients for lung cancer, and has started a pilot study in advanced lung-cancer patients. A Phase II/III trial is under way in sporadic adenomatous colonic polyps, and a pivotal Phase II/III study is ongoing for the prevention of disease recurrence in breast cancer patients. A Phase II study in Barrett's esophagus syndrome is also under way.

Cell Pathways intended to start a Phase I trial early this year with a compound, CP461, that appears stronger for cancer indications.

"It may be safer, and may be 10 to 100 times more potent [than Prevatac]," Towarnicki said. "But we're going to have to review and prioritize our efforts. It's just too early to tell."

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