It's not always immediately obvious why a product appears to work in one indication but not another. Cytel Corp. will spend the next few weeks pondering that question with regard to its Cylexin compound, a complex carbohydrate to block selectin.

CYTL halted its Phase II study of Cylexin after a scheduled interim analysis showed that the drug was safe, but had no benefit over placebo. The compound was being evaluated for myocardial salvage (saving heart tissue) in patients with acute myocardial infarction treated with angioplasty.