RATIONALE: Monoclonal antibodies such as rituximab can locate cancer cells and either kill
them or deliver cancer-killing substances to them without harming normal cells.
PURPOSE: Phase II trial to study the effectiveness of rituximab in treating patients who
have lymphoproliferative disorder that is associated with immunosuppression therapy.
OBJECTIVES: I. Evaluate the efficacy of rituximab in patients with B-cell
lymphoproliferative disorders while under pharmacologic immune suppression for control of
either allograft rejection or autoimmune disease. II. Evaluate the safety and direct
toxicity of rituximab in this patient population, including the potential for opportunistic
infections. III. Evaluate the secondary consequences of rituximab therapy in this
population, including changes in the requirement for immunosuppressive drugs, effects on
graft rejection, graft survival, and severity of autoimmune disease.
OUTLINE: Patients receive rituximab IV over several hours. Treatment repeats every week for
4 courses. Patients are followed every month for 6 months, and then every 3 months until
relapse or 2 years.
PROJECTED ACCRUAL: A total of 15 patients will be accrued for this study within 1 year.
DISEASE CHARACTERISTICS: Polyclonal or monoclonal B-cell lymphoproliferative disorder
while under pharmacologic immune suppression for control of either allograft rejection or
autoimmune disease Measurable disease as defined by one of the following: At least 1 tumor
mass measuring 1.0 cm in largest dimension Greater than 25% marrow involvement
Quantifiable extranodal disease Expression of CD20 antigen confirmed by biopsy or fine
needle aspirate Progression of disease or stable disease following reduction of
immunosuppressive medication and antiviral therapy Inability to further reduce
PATIENT CHARACTERISTICS: Age: 3 to 70 Performance status: Karnofsky 70-100% Life
expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,000/mm3
Platelet count at least 50,000/mm3 Hepatic: Not specified Renal: Not specified
Cardiovascular: No congestive heart failure Pulmonary: No pneumonitis Other: Not pregnant
or nursing Negative pregnancy test Fertile patients must use effective contraception
during and for 3 months after study No serious nonmalignant disease No active uncontrolled
bacterial, viral, or fungal infections
PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 4 weeks
since prior chemotherapy (6 weeks for nitrosoureas) No concurrent chemotherapy Endocrine
therapy: At least 2 weeks since change in dosing and type of immunosuppressive drugs
unless due to progression of disease Radiotherapy: At least 4 weeks since prior
radiotherapy No concurrent radiotherapy Surgery: At least 4 weeks since prior major
surgery (except diagnostic surgery) Other: At least 30 days or 5 half-lives since other
prior investigational drugs or whichever is longer