Mobilization of peripheral blood progenitor cells with paclitaxel-based chemotherapy

An essential component of combination high-dose chemotherapy and irradiation for the treatment of a variety of solid and hematologic malignancies is the ability to collect and reinfuse large numbers of peripheral blood progenitor cells (PBPCs). The reinfused PBPCs are used to replace pluripotent hematopoietic stem cells after marrow ablative therapy and to potentiate earlier blood cell count recovery after myelosuppressive (but not truly ablative) treatment. The PBPCs are mobilized from the marrow compartment into the peripheral bloodstream after treatment with chemotherapy, granulocyte colony-stimulating factor, or both. A number of single and combination chemotherapeutic agents have been used to mobilize PBPCs. In administering these agents, a balance must be found in all cases between effective PBPC mobilization and possible damage to the hematopoietic stem cell pool and overall patient tolerance. Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) causes no thrombocytopenia or cumulative hematopoietic toxicity and was found to effectively mobilize PBPCs without damaging the stem cell pool. Paclitaxel has the additional advantage of not causing the bladder toxicity seen with cyclophosphamide. Its antitumor effectiveness in breast and ovarian cancer makes it an especially useful component of therapy for both pretreatment cytoreduction as well as PBPC mobilization in these patients.