Maraviroc as GVHD Prophylaxis in Transplant Recipients

Maraviroc as Graft Versus Host Disease Prophylaxis in Pediatric and Adult Stem Cell Transplant Recipients

The purpose is to determine if the addition of Maraviroc to a standard transplant regimen will reduce the incidence of graft versus host disease in children and young adults after a stem cell transplant.

In the first stage, drug levels will be obtained to establish appropriate dosing. In the second stage of the study the investigators will study the effects of using Maraviroc in these patients.

Inclusion Criteria:

• Ages 5 years and </= 40 years
• All diagnoses
• Peripheral blood stem cells, marrow or cord blood
• All conditioning regimens
• Patient must be planned to receive a calcineurin inhibitor (cyclosporine or tacrolimus) together with steroid, methotrexate or mycophenolate mofetil as GVHD prophylaxis.

Exclusion Criteria:

• Documented anaphylaxis to Maraviroc
• Ex vivo T-cell (type of white blood cell) depleted grafts
• Abnormal Alanine Aminotransferase (ALT) (>/=10X ULN) on day -3. (Assessed at study enrollment and confirmed again prior to the first dose of maraviroc.)