A Phase IIa study of Sheffield Medical's red blood cell (RBC)-CD4 Complex for use as an AIDS therapeutic will be conductedat Johns Hopkins University, the company announced Monday.

Twelve patients will participate in the double-blind study,which will evaluate the anti-viral activity of the RBC-CD4complex on HIV viral load as measured by plasma p24 antigen,as well as the safety and tolerability of the product.

The complex is formed by electrically inserting HIV-bindingreceptor CD4 onto the surface of red blood cells. The resultingRBC-CD4 complex "acts like a sponge for free-floating HIV andforms aggregates with HIV-infected cells," Sheffield said. "Oncebound and internalized in the RBC-CD4, HIV disintegrates andis no longer infective."

Sheffield (NASDAQ:SHEF) of Houston expects to launch the trialin January after obtaining sufficient quantities of recombinantpurified CD4. In July, the company signed an agreement withCBR Laboratories Inc. (CBRL) for production and purification offull-length recombinant CD4. CBRL is a subsidiary of the Centerfor Blood Research Inc., an affiliate of Harvard Medical School.

CBRL developed the electroinsertion technology used toproduce the RBC-CD4 complex from Phase I. The technologyoriginated in an undisclosed private partnership; Sheffield hasan exclusive, worldwide sublicense to the technology.

In April, Sheffield reported that laboratory tests conducted byCBRL and St. Luke's Roosevelt Hospital in New York showedthat HIV from AIDS patients was not transmitted to new whiteblood cells in peripheral blood containing CD4 attached to redblood cells and the HIV did not infect macrophages. A Phase Itrial conducted at the Veterans Affairs Medical Center inHouston found that a "significant fraction" of the full-lengthCD4 protein remains on the red blood cell for its entire lifespan.

Sheffield was founded in 1991 through a reverse merger withan inactive existing company, Sheffield Strategic Metals. Thecompany finances the development of biomedical researchbeing conducted at universities and other research institutionsin return for licenses to commercialize the technology.

Of the three technologies Sheffield has licensed to date, RBC-CD4 is the first to reach clinicals. The other two technologies, anovarian cancer diagnostic and a prostate cancer diagnostic andtherapeutic, are licensed from Baylor College of Medicine.

The ovarian cancer diagnostic is based on an antigen believedto be produced in large quantities by ovarian cancers, and thuscould be used as an early marker of cancer. The prostatetechnology consists of a tumor growth-inhibitory factor, whichis lacking in people with prostate cancer. Baylor is conductingresearch to identify the gene that expresses the factor in orderto develop a therapeutic.

Sheffield's president and chief executive officer, Douglas Eger,told BioWorld the company is not focusing on particulartechnologies but instead looking to develop any products that"will fill a market need" and have a clear pathway tocommercialization. Sheffield will seek agreements with majorpharmaceutical companies instead of marketing products itself.

Sheffield's stock was down 88 cents a share on Monday, closingat $4.63.

-- Brenda Sandburg News Editor

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