Rituximab-Mediated Complement-Dependent Cytotoxicity Enhanced by Gemcitabine in Older Patients with Previously Rituximab-Treated Diffuse Large B-Cell Lymphoma: Study Protocol.

High-dose chemotherapy and autologous stem cell transplantation is too toxic for elderly patients with relapsed or refractory (DLBCL). Therefore, tolerable and efficient salvage regimens for elderly patients are greatly needed. In this study, therapy with rituximab, gemcitabine, dexamethasone, and cisplatin (R-GDP) will be performed every 4 weeks, and an interim evaluation will be performed after the completion of the 3rd course. If a complete response (CR) is achieved at the time of interim evaluation, 1 course of R-GDP therapy and 2 courses of monotherapy with rituximab will be additionally performed. If a partial response (PR) is achieved, 3 courses of R-GDP therapy will be additionally conducted. In patients without a PR or CR by the time of the interim evaluation, treatment will be discontinued. Treatment will also be discontinued at any point if disease progression is observed during protocol treatment. After the completion of the final course of R-GDP therapy, final effects of the regimen will be evaluated. A primary endpoint is the efficacy of R-GDP therapy (CR and response rates). This is the first multicenter phase II clinical study of R-GDP therapy to examine post-treatment activities of daily living in addition to the safety and efficacy of treatment in elderly patients with relapsed or refractory transplantineligible DLBCL.