Thalassemia is considered the most common genetic disorder worldwide, occurring with high frequency in Mediterranean areas, the Middle East, Southeast Asia, and the Pacific Islands. Currently, the only cure for thalassemia is bone marrow transplantation from a related, compatible donor. Gene transfer, achieved by transplantation of the patient's own blood stem cells that have been genetically-modified with the corrected gene, could potentially cure thalassemia. The first step in developing gene transfer for treatment of thalassemia is to develop a safe and effective method to obtain blood stem cells from thalassemia patients. Eventually, high numbers of genetically modified cells will need to be infused into the patient for clinical gene transfer to be effective. The blood stem cells are obtained by giving a "mobilization" agent to the patients. This causes the stem cells to leave the bone marrow and go into the blood. The purpose of this study is to test the safety and effectiveness of the new mobilization agent, Mozobil, in causing mobilization of blood stem cells for patients with beta-thalassemia major.
The purpose of this study is to optimize blood stem cell mobilization in adults with beta thalassemia major. We seek a method of mobilization that will be safe, with minimum side effects, and that will yield high numbers of blood stem cells. For successful gene therapy of thalassemia, high numbers of genetically modified stem cells will need to be introduced into the patient. Participants will include beta-thalassemia patients who failed to mobilize sufficiently with G-CSF (in our previous protocol) and new patients. In this study we will focus on the safety and effectiveness of mobilization with Mozobil or with Mozobil plus G-CSF. Following mobilization, blood stem cells will be recovered using leukapheresis, a procedure similar to a blood donation, in which mobilized white blood cells are collected from the blood of the patient. During drug administration and leukapheresis, patients will be hospitalized at George Papanicolaou Hospital in Thessaloniki, Greece. Patients who failed to mobilize in the previous protocol will receive Mozobil and G-CSF and will be hospitalized for 5-8 days for the duration of drug administration and leukapheresis. They will receive G-CSF for several days; Mozobil will be added on the last few days of G-CSF. New patients will receive Mozobil only and will be hospitalized for 2-3 days for drug administration and leukapheresis. Mozobil is administered at 240µg/kg, under the skin. Participants will undergo two or three leukapheresis procedures in a row if low numbers of blood stem cells were recovered in the first (and possibly second) leukapheresis. Participants will be discharged from the hospital the day following the last leukapheresis procedure. Weekly follow-up visits will occur for the next month, either at G. Papanicolaou Hospital, or at the participant's local doctor's office. The total period of study participation is approximately 5 weeks. In the event that Mozobil alone does not cause mobilization of high levels of blood cells, patients will be invited to repeat the protocol three months later, receiving Mozobil and G-CSF.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
20
Previously mobilized splenectomized patients who failed to yield sufficient numbers of cells with Mozobil alone will receive low doses G-CSF subcutaneously (starting at 2.5µg/kg/day and adjusted to the degree of leukocytosis), and Mozobil at 240µg/kg starting on the 4th or 5th day of G-CSF, followed by one to three leukaphereses. Previously non-splenectomized patients who failed to yield sufficient numbers of cells with Mozobil alone will receive G-CSF at 10µg/kg/day subcutaneously for 4-7 days, and Mozobil at 240µg/kg starting on the 4th or 5th day of G-CSF, followed by one to three leukaphereses.
Previously mobilized splenectomized patients who failed to yield sufficient numbers of cells with G-CSF in the previous study will receive low doses G-CSF subcutaneously (starting at 2.5µg/kg/day and adjusted to the degree of leukocytosis), and Mozobil at 240µg/kg starting on the 4th or 5th day of G-CSF, followed by one to three leukaphereses. Previously non-splenectomized patients who failed to yield sufficient numbers of cells with G-CSF in the previous study will receive G-CSF at 10µg/kg/day subcutaneously for 4-7 days, and Mozobil at 240µg/kg starting on the 4th or 5th day of G-CSF, followed by one to three leukaphereses.
Up to sixteen patients (splenectomized and non-splenectomized) who were not previously mobilized will receive Mozobil at 240µg/kg for one to three days, followed by one to three leukaphereses.
George Papanicolaou Hospital
Thessaloniki, Greece
Safety and effectiveness of Mozobil for mobilization of patients with beta thalassemia major
i) To determine the safety of peripheral blood stem cell (PBSC) mobilization with Mozobil alone or with Mozobil + G-CSF in adults with b-thalassemia major ii) To collect with Mozobil or Mozobil+G-CSF a total of at least 6 X 10e6 CD34+ cells/kg for a subsequent clinical beta-globin gene transfer trial.
Time frame: Five weeks
Clonogenic capacity, transducibility, and engraftment potential (in a mouse model) of genetically modified cells
Secondary: i)To determine the clonogenic capacity of cells mobilized by Mozobil alone, or by Mozobil + G-CSF, ii) To determine the cells' ability to be transduced with a recombinant lentivirus vector for beta-globin, iii) To determine the transduced cells' potential to engraft in a xenograft model.
Time frame: Six months
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