Rituximab in combination with high-dose dexamethasone for the treatment of relapsed/refractory chronic lymphocytic leukemia.

Background: High-dose methylprednisolone is active in treatment of relapsed/refractory chronic lymphocytic leukemia (CLL) but infectious toxicity is serious. The aim of this project was to retrospectively assess efficacy and safety of high-dose dexamethasone combined with rituximab (R-dex) in this setting.

Patients And Methods: We treated 54 patients (pts) with relapsed/refractory CLL using R-dex regimen at two tertiary centers. Two schedules of rituximab were used (not randomized - based on the choice of the center): group 1, rituximab 500 mg/m(2)day 1, 8, 15, 22 (375 mg/m(2) in 1st dose) every 4 weeks (n=29); group 2, 500 mg/m(2)day 1 (375 mg/m(2) in 1st cycle) repeated every 3 weeks (n=25). The target dose of dexamethasone was 40 mg on days 1-4 and 10-13 or 15-18. Rai III/IV stages were present in 82%, unmutated IgVH genes in 82%, del 11q in 38% and del 17p in 19% pts; 46% had bulky lymph nodes; 82% were pretreated with fludarabine and 29% with alemtuzumab.

Results: Overall response rate/complete remissions were 62/21% (Group 1) and 72/4% (Group 2). In three patients, R-dex was successfully used for debulking before nonmyeloablative allogeneic stem cell transplantation. R-dex was particularly effective in improvement of anemia and thrombocytopenia (p=0.0055 and p=0.0036); B-symptoms resolved after treatment in 11/17 pts. Hematological toxicity was mild. Serious infections occurred in 32% pts. At the median follow-up of 9 and 10 months, median progression-free survival was 6 months in Group 1 and 6.9 months in Group 2 (p=ns); median overall survival was 14.1 months in Group 1 vs. not reached in Group 2 (p=ns).

Conclusions: R-dex appears to be an active and feasible treatment for relapsed/refractory CLL. Infectious toxicity remains an important issue. Further investigation of this regimen in larger studies appears fully warranted.