Somatogen Inc. has published preclinical research showing thatits modified, mutated hemoglobin has promise as a bloodsubstitute.

Human hemoglobin itself is unsuitable as an oxygen carrier inblood because it holds onto oxygen too tightly in thebloodstream and disintegrates too readily into its constituentparts. Scientists at the Denver company and colleagues at theLaboratory of Molecular Biology in Cambridge, England,reported today in Nature that they have corrected theseproblems.

The human hemoglobin, produced in E. coli bacteria, is mutatedto decrease its oxygen affinity, allowing release of oxygen tothe tissues. Also, it is fused by a linking amino acid to preventbreakdown into the dimers that have caused kidney damage inprevious attempts at using hemoglobin as a blood substitute.

The Somatogen hemoglobin showed appropriate properties invitro and in rats and dogs, and did not appear to cause kidneyproblems, the researchers said. The team concluded that theengineered hemoglobin "is therefore a strong candidate for asafe blood substitute."

Somatogen (NASDAQ:SMTG) has started Phase I testing of thegenetically engineered product, said Charles Scoggins, presidentand chief executive officer. He told BioWorld that clinical datashould be available by early summer.

The blood substitutes market is estimated at $3 billionworldwide. Other companies pursuing blood substitutes includeBaxter Health Care Corp., Alliance Pharmaceutical Corp., TheUpjohn Co. (with BioPure Corp.), DNX Inc. and Enzon Inc.

Somatogen shares closed at $30, up 25 cents, on Wednesday. --Roberta Friedman, Ph.D.

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