Long-term results of the treatment of patients with mantle cell lymphoma with cladribine (2-CDA) alone (95-80-53) or 2-CDA and rituximab (N0189) in the North Central Cancer Treatment Group

BACKGROUND. The objective of this study was to test cladribine (2-CDA) alone and in combination with rituximab in patients with mantle cell lymphoma (MCL). METHODS. Patients with MCL were treated on 2 sequential trials. In Trial 95-80-53, patients received 2-CDA as initial therapy or at relapse. In Trial N0189, patients received combination 2-CDA and rituximab as initial therapy. In both trials, 2-CDA was administered at a dose of 5 mg/m² intravenously on Days 1 through 5 every 4 weeks for 2 to 6 cycles, depending on response. In Trial N0189, rituximab 375 mg/m² was administered on Day 1 of each cycle. RESULTS. Results were reported for 80 patients. Twenty-six previously untreated patients and 25 patients who had recurrent disease with a median age of 68 years received single-agent 2-CDA. The overall response rate (ORR) was 81% with 42% complete responses (CRs) in the previously untreated group. The median progression-free survival (PFS) was 13.6 months (95% confidence interval [95% CI], 7.2-22.1 months), and 81% of patients remained alive at 2 years. The ORR was 46% with a 21% CR rate in the recurrent disease group. The median PFS was 5.4 months (95% CI, 4.6-13.1 months), and 36% of patients remained alive at 2 years. Twenty-nine eligible patients with a median age of 70 years received 2-CDA plus rituximab. The ORR was 66% (19 of 29 patient), and the CR rate was 52% (15 of 29 patients). The median duration of response for patients who achieved a CR had not been reached at the time of the current report, and only 3 of the patients who achieved a CR developed recurrent disease at a median follow-up of 21.5 months. CONCLUSIONS. 2-CDA had substantial single-agent activity in both recurrent and untreated MCL, and the results indicated that it may be administered safely to elderly patients. The addition of rituximab to 2-CDA may increase the duration of response.