Hairy cell leukemia treated initially with purine analogs: a retrospective study of 107 patients from the Spanish Cooperative Group on Chronic Lymphocytic Leukemia (GELLC).

Abstract Purine analogs are highly effective in hairy cell leukemia (HCL) with response rates of 85%, but with many late relapses. We have retrospectively reviewed the clinical data from 107 patients treated with pentostatin (n = 27) or cladribine (n = 80), to investigate the long-term efficacy and to identify factors associated with the treatment-free interval (TFI). Complete remission and minimal residual disease (MRD) rates were similar in both groups. Median TFI was shorter (95 vs. 144 months) in the pentostatin group, although the difference was not significant (p = 0.476). MRD+ patients had shorter TFI than MRD- patients (97 months vs. not reached, p < 0.049). A hemoglobin level < 10 g/dL predicted for a shorter TFI only in the pentostatin group. Quality of response and number of hairy cells in the bone marrow are independent risk factors of treatment failure. The relationship between MRD+ and shorter TFI makes it of special interest to explore consolidation therapy with monoclonal antibodies to achieve durable responses.

Rituximab, fludarabine, cyclophosphamide, and mitoxantrone: a new, highly active chemoimmunotherapy regimen for chronic lymphocytic leukemia.

PURPOSE: The addition of monoclonal antibodies to chemotherapy has significantly improved treatment of chronic lymphocytic leukemia (CLL). Based on excellent results with the chemotherapy-only regimen fludarabine, cyclophosphamide, and mitoxantrone (FCM), we built a new chemoimmunotherapy combination--rituximab plus FCM (R-FCM). We report a phase II clinical trial consisting of an initial treatment with R-FCM followed by rituximab maintenance. PATIENTS AND METHODS: Seventy-two untreated CLL patients age 70 years or younger received rituximab 500 mg/m(2) on day 1 (375 mg/m(2) the first cycle), fludarabine 25 mg/m(2) IV on days 1 to 3, cyclophosphamide 200 mg/m(2) on days 1 to 3, and mitoxantrone 6 mg/m(2) IV on day 1, given at 4-week intervals with up to six cycles supported with colony-stimulating factor. Patients achieving response received maintenance with rituximab 375 mg/m(2) every 3 months for 2 years. RESULTS: The overall response, minimal residual disease (MRD) -negative complete response (CR), MRD-positive CR, and partial response rates were 93%, 46%, 36%, and 11%, respectively. Severe neutropenia developed in 13% of patients. Major and minor infections were reported in 8% and 5% of cycles, respectively. Advanced clinical stage, del(17p), or increased serum beta2-microglobulin levels correlated with a lower CR rate. CONCLUSION: R-FCM is highly effective in previously untreated CLL, with an 82% CR rate and a high proportion of MRD-negative CRs (46%). Treatment toxicity is acceptable. Parameters correlating with a lower response rate were advanced clinical stage, high serum beta2-microglobulin levels, and del(17p). Based on these results, R-FCM warrants further investigation in randomized clinical trials.