DNX Corp. has developed three transgenic pigs that producerecombinant human hemoglobin, putting it among a group ofbiotechnology companies pursuing widely varying strategies totap the $8 billion to $10 billion world market for bloodsubstitutes.

DNX inserts the gene for human hemoglobin into single-cell pigembryos. About 15 percent of the hemoglobin produced by thepigs is human. The company described its technology Sunday atthe 1991 World Congress on Cell and Tissue Culture inAnaheim, Calif.

"The real scientific achievement, which we're even moreexcited about, is the ease of separation (of human and porcinehemoglobin) using routine anion exchange chromatography,"Paul Schmitt, president and chief executive officer of thePrinceton, N.J., company, told BioWorld.

The production technology will keep product costs low, he said.DNX predicts that it will be able to produce hemoglobin for 60cents to 70 cents a gram and will sell it for $250 to $300 aunit, said Schmitt.

The privately held company said it hopes to begin clinicaltrials by late 1992 or early 1993.

Other companies developing hemoglobin products includeSomatogen Inc., Biopure Corp., Enzon Inc. and BiosourceGenetics Corp.

Biopure's partner, The Upjohn Co., in April suspended Phase Iclinical trials of Hemopure, a reconstituted hemoglobinpreparation from bovine blood, due to "transient" medicaleffects.

Somatogen of Boulder, Colo., plans to begin Phase I clinicaltrials this year of its hemoglobin, which is produced in E. colibacteria.

Enzon's PEG-hemoglobin links bovine hemoglobin withpolyethylene glycol to avoid the kidney toxicity associatedwith administration of hemoglobin and to minimize theimmune response caused by the foreign (bovine) protein. Thatproduct is in preclinical trials.

DNX will avoid kidney toxicity by utilizing cross-linking, amethod of holding the hemoglobin molecule together thatenables the kidney to excrete rather than accumulate it.Somatogen uses a genetic stabilization technology to keep themolecule together.

Biosource Genetics Corp. is field-testing tobacco thatexpresses components of human hemoglobin. The company's aimis to use plants as a factor for a number of compounds,including hemoglobin. -- Karen Bernstein

(c) 1997 American Health Consultants. All rights reserved.