CellPro Inc. announced Wednesday that it is ready to go aheadwith clinical trials on its Ceprate SC stem-cell concentrationsystem for allogeneic bone marrow transplants in patients withleukemia, lymphoma, severe aplastic anemia ormyelodysplastic syndrome.

The trials, to be held at the University of Utah Health SciencesCenter in Salt Lake City by principal investigator PatrickBeatty, are being conducted under a CellPro-sponsoredinvestigational device exemption (IDE).

The protocol involves using CellPro's cell concentration systemto purify stem cells (which express CD34 antigen) from themarrow and peripheral blood of donors who are either relatedto the patients but whose immune systems are not closelymatched, or donors whose immune systems are matched butwho are not related.

The purified stem cells will then be used to repopulate patientmarrow that has been destroyed by chemo- or radiotherapy.CellPro of Bothell, Wash., hopes to enroll 30 patients in the trial.

One patient has already been treated under this protocol, a 10-year-old boy with massive chest lymphoma who had relapsedinto acute lymphocytic leukemia (ALL) in the bone marrowfollowing whole-body radiation as well as chemotherapy,explained Lee Parker, CellPro's director of communications.

FDA approved that trial, which took place May 28, under acompassionate use exemption, Parker told BioWorld. In thiscase, the closest immunologically compatible donor availablewas the boy's father. The boy received a bone marrowtransplant and is well enough 82 days later to be close todischarge from the hospital. "The operation was a success, andhe doesn't have graft-versus-host (GVH) disease," Parker said.

The point of conducting these trials is to determine whether itis possible to reduce the incidence of GVH disease, which canlead to severe morbidity and mortality that occurs when thereis immunological incompatibility between an organ donor (inthis case bone marrow) and its recipient. The disease is causedby donor T-lymphocytes attacking tissues of the patient and isrelated to the degree of immunological incompatibility.

The ideal match would be twins, the second-in-line would besiblings, and parents rank third. After that comeimmunohistochemically matched but unrelated donors; herethe incidence of GVH can run as high as 30 percent.

In the trials about to begin at the University of Utah, theinvestigators will use CellPro's device to deplete the Tlymphocytes from donor bone marrow and peripheral blood.

Clinical trials on allogeneic bone marrow transplantation usingCellPro's system are already under way at the Johns HopkinsOncology Center in Baltimore. So far, 12 patients have beentreated, and CellPro has been "very pleased with the reductionin GVH," Parker told BioWorld.

"If this trial (in Utah) also demonstrates that the concomitantdepletion of T lymphocytes reduces the incidence and severityof GVH disease, it could lead to significant advances inallogeneic transplantation and greatly expand the pool ofpotential donors," said Ronald Berenson, vice president ofbiological research and medical affairs at CellPro.

-- Jennifer Van Brunt Senior Editor

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