Xoma Corp. and Ribi ImmunoChem Research Inc. on Mondaypresented data on two competing approaches to treating gram-negative sepsis.

Xoma's bactericidal/permeability increasing protein (BPI) killsmost gram-negative bacteria and inhibits the release of tumornecrosis factor and other cytokines in whole blood, according todata presented in Colorado on Monday at the KeystoneSymposium on Recognition of Endotoxin in Biologic Systems.

Pat Scannon, Xoma president, said BPI could worksynergistically with E5, the Berkeley, Calif., company'smonoclonal antibody treatment under FDA review. Scannontold BioWorld that BPI shares E5's ability to neutralizeendotoxin and "has the additional property of being able to killbacteria, which no other anti-sepsis drug under clinical trialcan now do. ... BPI neutralizes endotoxins, kills (gram-negative)bacteria and stops endotoxin-mediated cytokine production."

According to the paper, Xoma and New York University havecloned and expressed the biologically active portion of the BPImolecule. The researchers discovered that the recombinantlyproduced fragment retains its bactericidal properties in animalstudies.

Xoma plans to initiate human trials of BPI in the first quarterof 1993, Scannon said.

Ribi on Monday announced promising results from Phase I/IItrials of another treatment, monophosphoryl lipid A (MPL)immunostimulant. The trials demonstrated that MPLdiminishes the toxicity of endotoxin administered to humans,according to the company.

Healthy volunteers received either MPL or a placebo and thenwere challenged with a pharmacologically active but safe doseof endotoxin. All subjects in the control group had toxicreactions, while 50 percent of the MPL-treated group hadreactions.

In addition, cytokine levels associated with tissue damage andtoxic reactions were significantly reduced in the MPL-treatedgroup.

The Hamilton, Mont., company plans further Phase I/II trials inthe second half of this year. Its stock closed down 13 cents at$10.88 on Monday. -- SU

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