Rituximab for Prevention of Chronic GVHD

Study Design: The study is designed as a Phase II, open label trial of Rituximab as chronic
GVHD prophylaxis after HLA-matched, related or unrelated peripheral blood stem cell
transplantation after ablative or non-ablative conditioning.

Primary Objective: To determine the incidence of clinically extensive chronic GVHD at one
and two years after allogeneic stem cell transplantation after a single dose of Rituximab
administered at 100 days, 6 months, 9 months and 1 year from transplantation as chronic GVHD
prophylaxis.

Secondary Objectives: To determine the incidence of adverse hematological events, the
incidence of infectious complications, the rate of malignant relapse, and the effects on
donor hematopoietic chimerism after Rituximab administration.

Eligibility Criteria: Eligible patients will be 18 years of age or greater and will have
undergone a non-myeloablative or fully ablative transplantation from an HLA-matched (6/6
loci) or single antigen/allele mismatched (5/6) donor approximately 100 days ago. Adequate
performance status and organ function will be confirmed prior to enrollment. No ongoing
infection or acute GVHD will be present at the time of enrollment. Evidence of sustained
donor chimerism will be confirmed prior to study entry.

Treatment Description: Chronic GVHD prophylaxis will consist of Rituximab 375 mg/m2
administered 100 days, 6, 9 and 12 months after transplantation.

Accrual Objective: 68 patients will be accrued over 12 months.

Study Duration: Patients will be evaluated for two years after the time of transplantation
for evaluation of the primary and secondary endpoints. Subjects will be followed
longitudinally after completion of the study period for determination of clinical status.