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.