By Kim Coghill

Washington Editor

Isis Pharmaceuticals Inc. said Wednesday it is reinitiating development of ISIS 2302 in Crohn's disease, a drug that failed Phase IIb trials less than a year ago.

Officials from the Carlsbad, Calif.-based company said preparations are under way for Phase III trials to begin six to eight months down the road. In the meantime, Isis will conduct a small pilot study of the drug in order "to get more experience at different doses," said Karen Lundstedt, vice president of investor relations and corporate communications.

A recently completed analysis of the Phase IIb randomized trial indicates that patients who received higher exposure to ISIS 2302 were more likely to experience complete clinical remission, the primary endpoint of the study. Patients in total clinical remission were completely off steroids and symptom-free.

The analysis showed that patients' exposure to the drug varied based on gender and weight.

Lundstedt said Isis' further analysis of the trial data was to gain a better understanding of why the drug failed to perform when all preliminary data indicated that it would succeed. In December, Isis said the drug failed to demonstrate a statistically significant difference from placebo in 300 patients with Crohn's disease. (See BioWorld Today, Dec. 16, 1999, p. 1; and Jan. 19, 2000, p. 1.)

But the analysis reported Wednesday shows the response rate of patients exposed to higher levels of ISIS 2303 was 38 percent, compared to a 20 percent response rate for patients receiving placebo, Stanley Crooke, Isis chairman and CEO, said during a conference call. That difference is statistically significant (p<0.03), he said.

Even though all patients received a 2 mg/kg dose of ISIS 2302, the analysis showed that heavier people and females received higher exposure to ISIS 2302 than lighter people and males, Bruce Yacyshyn, associate professor, Division of Gastroenterology and Medical Microbiology and Immunology, University of Alberta, said during a conference telephone call.

The randomized trial was a 300-patient multicenter, double-blind trial that compared the effects of two weeks and four weeks of treatment with ISIS 2302 to placebo. Crohn's disease is a chronic inflammatory disease that can affect any part of the gastrointestinal tract but most commonly affects the ileum.

"We've now come up with the appropriate information that's going to allow us to design a trial that's going to produce the exposure levels in plasma which we've associated with higher response rates in this stage of the trial," said Arthur Levin, vice president of toxicology and pharmacokinetics for Isis.

Crooke said Isis will proceed with ISIS 2302 because there's an unmet medical need, the drug will provide significant relief for patients suffering with Crohn's, the expenses related to further development are modest and the company has a clear direction on how to proceed with development.

ISIS 2302 is an antisense inhibitor of intercellular adhesion molecule-1, a molecule that plays a central role in inflammation. Phase II trials of a topical formulation ISIS 2302 for psoriasis and an enema formulation for ulcerative colitis are ongoing.

Isis has 11 products in its development pipeline, six of which are in Phase II clinical trials

According to a statement released by Crooke, Isis had $126 million in cash at the end of the second quarter.

Isis' stock (NASDAQ:ISIP) closed at $10.875 Wednesday, up 37.5 cents.

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