CELLPRO TECHNOLOGY USED IN NOVEL GENE THERAPY TRIAL; Multidrug Resistance Gene May Permit More Aggressive Taxol Therapy For Ovarian Cancer.

SEATTLE--(BUSINESS WIRE)--Feb. 1, 1995--CellPro, Inc. (Nasdaq: CPRO) announced today that the company's CEPRATE SC Stem Cell Selection System is being used to purify CD34 antigen-expressing stem and blood progenitor cells from the bone marrow of advanced ovarian cancer patients in a Phase I/II clinical trial. The trial is under way at The University of Texas M.D. Anderson Cancer Center in Houston. Primary endpoints of the trial are to test the safety and feasibility of using a multidrug resistance gene to protect normal bone marrow cells against toxic anticancer drugs.

"Animal studies have demonstrated that this multidrug resistance gene provides cells with the ability to pump toxic drugs out of the cell," said Albert Deisseroth, MD, chairman of the Department of Hematology at M.D. Anderson Cancer Center and principal investigator for the trial. "The intended clinical result is to chemoprotect healthy cells, specifically bone marrow stem cells, from larger doses of anticancer agents, while allowing the higher levels of chemotherapeutics to more effectively attack tumor cells."

The trial is expected to accrue 10 patients who have been unsuccessfully treated with conventional chemotherapy. The protocol calls for CD34+ stem and progenitor cells to be purified from the bone marrow of patients using CellPro's CEPRATE SC System. Stem and early progenitor cells are among the most chemo-sensitive cells in the body and are responsible for the important function of producing all the new cells of the blood and immune systems. Once purified using CellPro's CEPRATE system, these specialized bone marrow cells will be genetically modified in the laboratory to express MDR-1, a multidrug resistance gene known to produce a cellular anti-toxin pump. The genetically altered cells (equipped with this new pumping mechanism) are then infused into patients who subsequently receive aggressive doses of taxol, one of the more promising new drugs emerging for treating selected cancers. "Our strategy in this trial is to give patients increasingly larger doses of taxol every three to four weeks with the expectation that the genetically altered bone marrow cells, and the progeny of those cells, will get stronger with each cycle of chemotherapy," explained Dr. Deisseroth.

Although they are leading therapies for cancer, chemotherapeutic drugs are highly toxic and can produce life-threatening side effects. Besides actively dividing cancer cells, cells of the intestinal and hematopoietic (blood forming) systems are also particularly sensitive to these drugs. This can result in serious side effects including hemorrhaging, anemia and infections. Dr. Deisseroth's team of investigators aims to enhance chemotherapy tolerance through insertion of the MDR-1 gene into stem and progenitor bone marrow cells, which can pass the protection mechanism afforded by the gene to newly formed blood cells. "Our first trial is focused on advanced ovarian cancer patients who do not exhibit cancer cells in bone marrow, but we intend to investigate this experimental gene therapy in other diseases, including breast cancer," added Dr. Deisseroth. "We are pleased to expand our relationship with M.D. Anderson Cancer Center, an institution at the forefront of cancer treatment," said Ronald J. Berenson, MD, CellPro's executive vice president and chief medical and science officer. "Our CEPRATE SC System's ability to purify CD34+ stem cells is an integral part of many of the most innovative cancer treatments under development where specific, reliable cell selection and purification is a critical step in the treatment protocol."

The University of Texas M.D. Anderson Cancer Center in Houston ranks as one of the world's most respected and productive Comprehensive Cancer Centers as designated by specific federal criteria. The Center is devoted exclusively to cancer patient care, research, education and prevention. The CEPRATE SC Stem Cell System is designed to isolate and purify stem cells from patients' peripheral blood or bone marrow. The system uses a patented avidin-biotin binding system to obtain sufficient quantities of stem cells for use in reconstituting bone marrow cells following cancer chemotherapy and in other stem cell-related therapies affecting the blood and immune systems. Additionally, the CEPRATE SC System is valuable as a cell-separation tool for research in gene therapy. The System first became commercially available in Europe, in September 1993, and is currently being tested in over 60 clinical trials in the US, Canada, Europe and Australia for various applications including various gene therapy applications. More than 1,000 patients at over 100 hospitals in 20 countries have been treated in protocols requiring cell separation with the CEPRATE SC System.

Located in Bothell, Washington, CellPro Inc. is a biotechnology company specializing in the development, manufacturing and marketing of proprietary continuous-flow, cell-selection systems for use in a variety of therapeutic, diagnostic and research applications.

CONTACT: CellPro, Incorporated

Lee M. Parker, 206/485-7644

OR

M D Anderson Cancer Center

Jane Brust, 713/792-0655