Publication of a multicenter trial of Xoma Corp.'s E5 antibodyto endotoxin has shown positive but limited effects for thedrug in patients with gram-negative sepsis.

Berkeley, Calif.-based Xoma's stock (NASDAQ:XOMA) jumped 50cents on the report Tuesday, to $19.25. Rival Centocor Inc.(NASDAQ:CNTO) fell $1.25 to $33.75.

But an editorial accompanying the report in the Journal of theAmerican Medical Association suggested that doctors shouldremain cautious about using the drug if it is approved by theFood and Drug Administration.

In the study of 468 patients, E5 failed to increase survivalfollowing gram-negative sepsis. But for the subgroup ofpatients who received the drug before they had developedcirculatory shock, survival rates increased by a factor of 2.3.

In addition, reversal of organ failures in the antibody-treatedpatients did occur significantly more frequently than in aplacebo-treated group.

A study published last February in the New England Journal ofMedicine suggested that E5 would be the less effective thanCentocor's Centoxin. The Malvern, Pa.-based company's antibodyimproved sepsis outcome regardless of whether shock waspresent. However, letters appearing in the NEJM'scorrespondence section last month roundly criticized theCentocor study.

An FDA advisory panel is scheduled to review both drugs nextweek. If the drugs are approved, "physicians will be faced withseveral dilemmas," according to the JAMA editorial by Roger C.Bone, a sepsis expert at Rush-Presbyterian-St. Luke's MedicalCenter in Chicago.

Bone said no patient should be given the drugs unless gram-negative sepsis is strongly suspected. Given the lack of aclinically useful test that can report that sepsis is indeedpresent, Bone said, doc-tors should use the drugs only if theirpatients' conditions match the clinical definitions of sepsis inthe Centocor and Xoma trials.

"Neither product decreased mortality in the entire populationof patients studied," Bone stated. "Therefore, treatment witheither agent is a matter of clinical judgment."

Bone added, "The experimental data are sufficiently equivocalthat I do not believe a physician could be held negligent for notusing these products at the present time."

More studies will be needed, preferably a head-to-headcomparison of the two antibodies, to recommend theirunrestrained use, Bone concluded.

-- Roberta Friedman, Ph.D. Special to BioWorld

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