Dismutec, a drug intended to reduce the damage of closedhead trauma, failed to produce statistically significantimprovement in patients over controls in its second PhaseIII trial, the company said Friday.

Sanofi Winthrop Inc., of New York _ which waslicensed by the product's inventor, Enzon Inc., tomanufacture Dismutec and bring it to market _conducted both Phase III trials. The first trial involved460 subjects; the second was much larger, with 1,600subjects.

When Sanofi Winthrop broke the code and examined thedata collected in the latest trial, it found that the drug "didnot show any statistically significant difference betweenthe treatment group and the control group," companyspokesman Terry Kelley told BioWorld Today.

Kelley said although the company has not yet made anyfinal decision on whether or how to proceed, Dismutec'sfuture as a treatment for head trauma looks bleak.

Enzon, of Piscataway, N.J., and Portland-based OxisInternational Inc., which makes a key enzyme used inDismutec, hastened to assure the public that the drug'sfailure would have little immediate impact on earnings,cash flow or the future prospects of their other products.

Oxis (NASDAQ:OXIS) closed down 31 cents Friday to$1.94. Enzon (NASDAQ ENZN) lost 13 cents to finishthe day at $3.06.

The enzyme is called bovine superoxide dismutase(SOD). In Dismutec, it is attached to a polyethyleneglycol base. Researchers had theorized that SOD, a freeradical scavenger, would reduce brain damage by soppingup the wildly destructive free radicals that are acomplication of severe head injury.

But SOD, viewed as a promising treatment for a range ofailments from heart attacks to osteoarthritis, has proven tobe a risky approach to therapy.

Its half life is so short, and its potential for triggering animmune response so great, that a therapeutic dose can behighly toxic.

In an effort to reduce the drug's toxicity, Enzondeveloped a polyethylene glycol (PEG) base. The PEGtechnology works in two ways, said Enzon representativeKenneth Zuerblis.

It extends the enzyme's half-life so that doctors canadminister a therapeutic dose gradually, and it reducesSOD's ability to trigger a harmful immune response.

Zuerblis said that Enzon's patented technology worked tosome extent _ Dismutec performed well in Phase IIsafety trials. "Unfortunately," he said, "the Phase III trialproved that the doses given did not have a statisticallysignificant therapeutic effect." n

-- Steve Sternberg Special To BioWorld Today

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