Phase 1/2 study of fractionated (131)I-rituximab in low-grade B-cell lymphoma: the effect of prior rituximab dosing and tumor burden on subsequent radioimmunotherapy.

The effect of induction therapy with multiple doses of rituximab on the subsequent efficacy and toxicity of anti-CD20 radioimmunotherapy is unknown. We evaluated a novel protocol using 4 weekly infusions of 375 mg/m(2) rituximab followed by 2 fractions of (131)I-rituximab, preceded by a 100-mg/m(2) predose of rituximab, in relapsed indolent B-cell lymphoma. Induction therapy with rituximab significantly increased the effective half-life of (131)I-rituximab (P = .