Mycophenolate Mofetil (MMF) for Treatment of Chronic Graft-versus-host Disease (GVHD)

DISEASE CHARACTERISTICS: * Newly diagnosed chronic-graft-versus host disease (GVHD) * Systemic immunosuppressive treatment indicated AND no contraindication to treatment with mycophenolate mofetil * Has undergone prior transplantation with any type of donor, hematopoietic stem cell graft, or conditioning regimen * No clinical, laboratory, or image-based evidence known to be present at the time of enrollment and indicating a high probability of subsequent recurrent or progressive disease PATIENT CHARACTERISTICS: Age * Any age Performance status * Not specified Life expectancy * Not specified Hematopoietic * Absolute neutrophil count ≥ 1,500/mm\^3 Hepatic * Not specified Renal * Not specified Pulmonary * No known bronchiolitis obliterans as a manifestation of chronic GVHD Immunologic * No fungal infection without radiographic evidence of improvement during continued antifungal therapy * No cytomegalovirus (CMV) pneumonia without major radiographic evidence of improvement * No other CMV infection without reduction of antigenemia or viral load during continued antiviral therapy * No active disseminated varicella zoster viral infection * No known hypersensitivity or allergy to MMF Gastrointestinal * Able to tolerate oral medication * No lactose-intolerant children who are too young to swallow capsules * No frank blood from the rectum * No melena * No known gastrointestinal ulceration Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Female patients must use 2 forms of contraception 4 weeks prior to, during, and for 6 weeks after completion of study treatment * Not hospitalized at time of enrollment * No rare, hereditary deficiency of hypoxanthine-guanine phosphoribosyl-transferase (HGPRT) PRIOR CONCURRENT THERAPY: Biologic therapy * See Disease Characteristics Chemotherapy * Not specified Endocrine therapy * Prior treatment with prednisone or equivalent allowed provided the dose was ≤ 1.0 mg/kg/day at the time of enrollment * Concurrent systemic glucocorticoids allowed Radiotherapy * Not specified Surgery * Not specified Other * Prior mycophenolate mofetil (MMF) for prevention or treatment of acute GVHD allowed provided MMF was discontinued at least 2 weeks before the diagnosis of chronic GVHD was made * No prior systemic treatment for chronic GVHD * No prior treatment for chronic GVHD * Concurrent antacids allowed provided there is at least a 2-hour interval before and after administration of MMF * No other concurrent systemic immunosuppressive treatment except cyclosporine, tacrolimus or sirolimus