Number of blood substitute options may shrink
by Thomas A. McCalden, Ph.D.
HCNS Contributing Editor
Wednesday, June 25, 1997
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It seems increasingly clear that one kind of hemoglobin will NOT be available on pharmacy shelves as an alternative to transfused whole blood. The product which may not make it is the recombinant hemoglobin Optro which is being developed by Somatogen of Boulder, Colo. Somatogen was in collaboration with pharmaceutical giant Eli Lilly for final clinical trials, manufacture and marketing of the blood substitute. However, the March 1997 announcement from Lilly that they were terminating the joint development agreement seems to have doomed the further development of Optro in the view of many financial industry analysts.
This bump in the road for Optro has been produced not as a result of a failure in the progress of scientific development. A Phase 1 clinical trial had been completed and a Phase 2 trial is in progress. However, it seems that Eli Lilly decided that the estimated market of $1 billion simply did not exist. Indeed, since the safety of the whole blood supply has been vastly improved, many analysts also estimate that the market may indeed not be as large as originally estimated. However, Optro is one of the most financially vulnerable of the various artificial blood products being developed. The recombinant technologies required to produce Somatogen's product are more expensive than for other artificial blood products such as HemeAssist being developed by Baxter Healthcare Inc.
Despite this setback for Somatogen, they are moving along -- alone. On April 29 1997, they announced they would begin enrollment of patients for a Phase 2 study of the use of Optro in coronary bypass surgery. The goals of this Phase 2 trial seem limited. Somatogen will determine if Optro administration before surgery can enhance the amount of autologus blood that may be removed from the patient before the surgery commences. In this way more autologus blood will be available to the patient during and after the surgery.
Despite these setbacks for Optro, it still remains to be seen which hemoglobin products succeed in reaching the artificial blood market. Other major products could be:
Modified outdated human blood (Baxter Health Care)
Modified outdated human blood (Northfield Laboratories)
Bovine derived hemoglobin (Biopure)
Perflurocarbons (Alliance Pharmaceutical Corp.)
The hemoglobin extracted from human or bovine blood may suffer from the perception that it may be capable of transmission of an infectious agent from donor to human host. The likelihood of this is probably low. However, Genentech's recombinant growth hormone was catapulted to instant commercial success by the discovery of a slow virus contaminating the cadavers used for production of natural growth hormone. So, while it appears that modified human hemoglobin is ahead in the race to market, anything can still happen!
Prof. McCalden is associate professor of pharmacology in the College of Veterinary Medicine and Biomedical Science at Colorado State University. He has been active in academic and industrial biomedical research for 25 years.
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