Rituximab and Combination Chemotherapy in Treating Patients With Previously Untreated High- or High-Intermediate-Risk Diffuse Large B-Cell Lymphoma

PRIMARY OBJECTIVES: I. To evaluate 1 year progression-free survival (PFS) following treatment with rituximab intense dosing and CHOP-21 (RID-CHOP) in previously untreated patients with high risk (International Prognostic Index \[IPI\] 3-5) DLBCL. SECONDARY OBJECTIVES: I. To evaluate, in previously untreated patients with high risk (IPI 3-5) DLBCL treated with rituximab intense dosing and CHOP-21: Complete response (CR) rate, (as defined by International Harmonization Project criteria using 18-fluorodeoxyglucose \[FDG\] -positron emission tomography \[PET\]/computed tomography \[CT\]). II. Overall survival. III. Toxicity profile. IV. Rituximab pharmacokinetics for this dose and schedule. V. Effect of immunophenotype of DLBCL on outcome. VI. Effect of Fc-Gamma Receptor III (FcyRIII) polymorphism genotype on outcome. OUTLINE: Patients receive rituximab intravenously (IV) on days 0, 1, 4, 8, and 15 of course 1; days 1, 8, and 15 of course 2; and day 1 of all subsequent courses. Patients also receive CHOP chemotherapy comprising cyclophosphamide IV, doxorubicin hydrochloride IV, and vincristine sulfate IV on day 1, and prednisone orally (PO) on days 1-5. Treatment repeats every 21 days for 6 courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 2-3 months for 2 years, every 6 months for 3 years, annually for up to 10 years.