Sirolimus in Combination With Metronomic Chemotherapy in Children With Recurrent and/or Refractory Solid and CNS Tumors

The starting dose for sirolimus is 2 mg/m2 once daily. The dose of sirolimus will be individually adjusted to achieve a target serum trough concentration in the range of 10-15 ng/ml. Sirolimus will be given by mouth every day for six weeks (every six weeks is called one cycle) for up to two years or 16 cycles.

Celecoxib 100 mg will be given by mouth twice a day for six weeks (every six weeks is called one cycle) for up to two years or 16 cycles.

Etoposide 50 mg/m2 (maximum dose 100 mg) will be given daily by mouth for the first 3 weeks of a 6 week cycle. Six week cycles will be repeated for up to two years or 16 cycles.

Cyclophosphamide 2.5 mg/Kg (maximum dose 100 mg) will be given daily by mouth for the second 3 weeks of a 6 week cycle. Six week cycles will be repeated for up to two years or 16 cycles.