Trial Information

Mobilization by Plerixafor of Haematopoietic Stem Cells in Children

The extensive chemotherapy followed of hematopoietic stem cells reinjection (HSC) is one
therapeutic option which the profit is well demonstrated in the treatment of children's
solid tumors. It's one of the "standard" treatment of the following tumors: neuroblastoma,
metastatic medulloblastoma, Ewing sarcoma, lymphoma in relapse; and because of the big
chemosensibility of paediatric cancers, stays an important therapeutic option in the
rhabdomyosarcoma in relapse or metastatic, nephroblastoma, etc. The stem cells can be taken
in the blood by cytapheresis after mobilization with pharmacologic molecules. At present,
the reference of the mobilization treatment is the G-CSF (Granulocyte colony-stimulating
factor) in monotherapy during 4 to 6 days. His inconveniences are: lasted of the treatment
(4 to 6 days), reproduction of the injections (1 to 2 subcutaneous injections daily), day
variability of the peak of mobilization, this hematopoietic stimulation imposes to delay the
chemotherapy. The plerixafor activates a massive and fast mobilization of the HSC (
hematopoietic stem cells)(between 6 and 11 hours after the injection). Currently, it's
indicated in association with the G-CSF ( Granulocyte colony-stimulating factor)in case of
mobilization failure. However, his big flexibility of use could be of a big interest in
monotherapy at the child. To date, there is in our knowledge no data on the use of this
molecule at the child.

Schema of study: Subcutaneous injection of 240 µg/kg of Plerixafor (Mozobil ®, Genzyme) at 8
am the day of the cytapheresis. Determination of CD34+ cells circulating in h0 then every
hour of h3 to h11. Taking by cytapheresis from the 5th hour of the injection if the rate of
CD34+ is upper or equal in 10.106/l. If the rate of CD34+ in the blood does not reach
10.106/l after the first injection of plerixafor or if the first cytapheresis does not allow
the collection of at least 5.106/kg CD34+ cells, the patient will be considered in failure
and a conventional mobilization by G-CSF(Granulocyte colony-stimulating factor) will be
programmed.