CellPro Inc. said Wednesday that it started a clinical trial of aprocess that uses the company's Ceprate SC Stem CellConcentration System to collect stem cells from the peripheralblood of cancer patients who are about to undergochemotherapy.

If successful, the process could eliminate the more complicatedH and uncomfortable H procedure for extracting stem cellsfrom a patient's bone marrow through large-bore needlesinserted into the pelvis. This existing procedure, calledautologous bone marrow transplantation (ABMT), is performedprior to some high-dose chemotherapies, such as the in thetreatment of recurrent breast cancer. The stem cells are laterreinfused into patients following chemotherapy.

The study is to determine if the stem cells gathered with theCeprate SC Stem Cell Concentration System are at least aseffective in restoring a chemotherapy patient's blood andimmune system as those gathered with ABMT.

CellPro's ultimate aim is a bit more ambitious H replacing manybone marrow transplants. "We believe the future course oftreatment for many cancers is with stem cells isolated fromperipheral blood as an adjunct to aggressive chemotherapy,"said Ronald J. Berenson, CellPro's vice president of biologicalresearch and medical affairs.

"Our objective is to replace bone marrow transplantation withnon-invasive, peripheral-blood stem cell therapy for thesupport of high-dose chemotherapy in treating many cancers,"he said. Easier access to replacement stem cells may allowphysicians to prescribe stronger anti-cancer therapies.

Stem cells produce all other cells of the body's blood and

immune system. Although most stem cells are found in thebone marrow, a small number circulate in the peripheral blood.Because stem cells are destroyed in potent chemotherapies,some of the cells are removed from a patient's marrow beforechemotherapy for later reinfusion.

The trial announced Wednesday is to be conducted at fivemedical centers, including the University of Colorado HealthSciences Center where 10 chemotherapy patients

have already undergone similar treatment. About 50 patientswill be treated under the new study.

The earlier Colorado study showed that adding transplantedstem cells from peripheral blood to purified marrow stem cellsin combination with granulocyte-colony stimulating factor (G-CSF), actually speeded up engraftment of the reinfused towithin 10 days, compared to the 20 to 25 days with ABMT-sourced cells alone, according to CellPro.

The study also showed that the addition of peripheral-bloodstem cells reduced the time needed for the patient's marrow torecover the ability to produce platelets, the blood cellsresponsible for clotting. The 10 patients averaged just threesubsequent platelet transfusions compared with the 10normally required in a standard ABMT.

"Adding purified peripheral-blood stem cells to transplantedmarrow in this phase of the trial significantly reducedcomplications and shortened hospital stays by reducing thetime to engraftment," said CellPro's Berenson. Data from theColorado study were presented July 30 to a meeting of theInternational Society of Experimental Hematology.

"The next step," Berenson said, "is to test whether peripheral-blood stem cells transplanted without any bone marrow canlead to rapid and durable engraftment."

A final step in the company's quest is to culture a patient'sstem cells in vitro, which would greatly reduce the number ofstem cells to be removed from the patient.

-- Ray Potter Senior Editor

(c) 1997 American Health Consultants. All rights reserved.