A Phase II Trial of Rituximab-CHOP Chemotherapy Followed by Yttrium 90 (Y-90) Ibritumomab Tiuxetan (Y-90-IT) for Previously Untreated Elderly Diffuse Large B-Cell Lymphoma (DLBCL) Patients

Introduction: In 2008 we published a phase II trial abuot the combination of 6 cycles of CHOP plus 90Y-IT for previously untreated elderly patients with DLBCL. The CCR was 95% with OS at 2 years of 95% and PFS at 2 years of 75%. The results of this study support a further evaluation of 90Y-IT in combination of chemotherapy. We conducted a prospective, single-arm, non-randomized, phase II trial with CHOP plus Rituximab followed by 90Y-IT reducing the number of CHOP cycles from 6 to 4 but introducing Rituximab. The rational is to utilize all the therapeutic approaches (chemotherapy, immunotherapy and radioimunotherapy) reducing conventional chemotherapy and probably related toxicity. Patients and Methods: Patient elegibility was represented by: patients older than 60 years with biopsy proven, untreated, bidimensionally mesurable stage II, III or IV DLBCL. Expression the CD-20 antigen; WHO performance status of 0 to 2. patients were treated with standard CHOP chemotherapy plus Rituximab every 21 days for 4 cycles. Patients were restaged 4 to 6 weeks after completion of 4 cycles of R-CHOP chemotherapy. Patients achieving CR, PR or SD after chemotherapy were eligible for consolidation with 90Y-IT provided the granulocyte count was greater than 1500/microl, the platelet count exceded 100.000/microl and the bone marrow examination at the completion of chemotherapy demostrated no more than 25% involvement with lymphoma. All patients were to receive a single dose of 90Y-IT 14.8 MBq/kg (0.4 mCi/kg). Fifty-five patients have been enrolled: 26 were male and 29 female; the median age was 70 years (range 60–83); 17 were stage II, 38 were stage III-IV. Results: Fifty-one patients had completed the R-CHOP treatment and the overall response rate was 94.1% including 30 (58.8%) of patients in CR and 17 (35.3%) in PR. Treatment was well tolerated; grade 3–4 AEs are comparable with previous experience and the most common grade 3–4 AEs was neutropenia. At this time 47 patients had just received 90Y-IT and 45 are evaluable. In particular, 9/17 (52.9%) patients converted from PR to CR after treatment with 90Y-IT. Conclusions: These preliminary data indicate that radioimmunotherapy appears highly effective and feasible as "consolidation" after 4 cycles of immunochemotherapy in elderly DLBCL patients, improving quality of response without any cumulative toxicity.