Phase I/II tests of CellPro Inc.'s stem cell concentrator showedthat the method was successful in cancer patients, with relatedtests suggesting that stem cells someday might be collectedfrom blood instead of bone marrow, and multiplied with colonystimulating factor.
Available processes to repair immune function afterchemotherapy purge a patient's marrow of tumor cells, but canalso damage the precursor cells needed to reconstitute theimmune system.
CellPro's Ceprate SC Stem Cell Concentrator pulls stem cellsfrom marrow by collecting the cells that bear the CD34 markermolecule on their surface. These CD34-bearing stem cells cangenerate the entire set of blood cells.
The study of Ceprate in 24 cancer patients at the University ofColorado Health Sciences Center in Denver showed thatreinfusion of CD34-bearing marrow cells after chemotherapyprovided patients with normal cell counts and immunefunction, and all grafts of the enriched marrow succeeded. TheBothell, Wash., company (NASDAQ:CPRO) reported the resultslast week at a scientific conference.
The patients had backup marrow banked in case theexperimental treatment failed, said Dr. Ronald J. Berenson, vicepresident for research. He told Bioworld that a Phase III trialwill start this spring.
CellPro also will start clinical trials of stem cells harvested fromblood "within the next couple of months," Berenson said.
The Denver study also compared recovery of patients whoreceived the colony stimulating factor G-CSF, which didaccelerate replenishment of the granulocytes, the study'sinvestigator reported.
A separate study, conducted with the University of Coloradoand the Fred Hutchinson Cancer Research Center in Seattle,reported that G-CSF increased colony-forming progenitor cellsthat could be purified and recovered by the Ceprate system.
The study raises the possibility that marrow transplants maynot be necessary. By using CSFs, stem cells can be increasedfrom their usually minute amounts in blood, separated by thecompany's system, then increased in lab culture by 50 to 100fold. Stem cells typically comprise 1 percent of marrow, butonly one-tenth of a percent of circulating blood cells.
The Denver investigator is now studying the effect of addingstem cells, collected from blood of patients given Amgen Inc.'sG-CSF, to CD34-positive cells concentrated from marrow.
CellPro shares gained 25 cents to $17.
-- Roberta Friedman, Ph.D. Special to BioWorld
(c) 1997 American Health Consultants. All rights reserved.