Peripheral Blood Stem Cell (PBSC) Mobilization in Patients With Relapsed Lymphoma Treated With Bendamustine

Patients with certain types of cancer require treatment with very high doses of chemotherapy. A side effect of high chemotherapy doses is damage to the bone marrow where our blood and immune system cells are produced. Stem cells (or progenitor cells) are the source of all blood cells. They are formed in the bone marrow (the spongy cavity in the center of large bones). The stem cells receive signals that direct them to become red cells, white cells or platelets. This happens before they are released into the blood stream. Stem cells circulating in the blood stream can be collected through a process called "apheresis" or "stem cell collection". The cells are then processed and frozen to preserve them. After chemotherapy has been given the stem cells are thawed and given back intravenously (IV: into the vein), like a blood transfusion. The stem cells in the collection will find their way back into the bone marrow space and, after a few days, will start to produce the blood and immune cells as they normally would. Having your own stem cells collected and returned to you later is called an "autologous transplant." Non-Hodgkin's lymphoma is a disease in which malignant cancer cells form in the lymph system. Autologous stem cell transplantation is the standard of care for a chemo-sensitive relapse in patients with large cell lymphoma that has spread. Bendamustine works by blocking the growth of cancer cells. It is used for the management of chronic lymphocytic leukemia and follicular lymphoma. Bendamustine in addition to rituximab (BR) is used in several trials in patients with lymphoma with encouraging results. Adequate peripheral blood stem cell (PBSC) collection is a pre-requisite for high dose therapy followed by cell transplantation in patients with relapsed lymphoma. Exposure to previous multiple chemotherapy and radiation treatment may lead to poor mobilization of PBSC. It is not known whether pre-treatment with bendamustine will adversely affect the process of PBSC mobilization and harvest. On the other hand, it is assumed that high dose alkylating agents like cyclophosphamide may actually help in breaking the bond between stem cells and the stromal cells in the marrow cavity and hence may lead to a better mobilization of PBSC.