Glucocorticoid-based combination therapy for chronic lymphotic leukemia: new tricks for an old dog

Five years of experience with rituximab plus high-dose dexamethasone for relapsed/refractory chronic lymphocytic leukemia

INTRODUCTION

High-dose methylprednisolone (HDMP) in combination with rituximab is active in the treatment of relapsed/refractory chronic lymphocytic leukemia (CLL), but serious infections are frequent. Recently published data suggested that high-dose dexamethasone might be equally effective as HDMP despite a lower cumulative dose.

MATERIAL AND METHODS

We performed retrospective analysis of 60 patients with relapsed/refractory CLL (median age: 66 years; range: 37-86) treated with rituximab plus dexamethasone (R-dex) at a single tertiary center between September 2008 and October 2012. The schedule of R-dex consisted of rituximab 500 mg/m(2) i.v. day 1 (375 mg/m(2) in cycle 1) and dexamethasone 40 mg orally on days 1-4 and 10-13 repeated every 3 weeks for a maximum of 8 cycles. Unfavorable prognostic features were frequent (Rai stages III/IV in 67%, unmutated IgVH 82%, del 11q 43%, TP53 mutation/deletion 23%, bulky lymphadenopathy 58% of patients).

RESULTS

Overall response (OR)/complete remission (CR) was achieved in 75/3%. At the median follow-up of 21 months, median progression-free survival (PFS) was 8 months, median time to next treatment 12.9 months and median overall survival 25.5 months. Refractoriness to fludarabine (p = 0.04) and age ≥ 65 years (p = 0.03) were significant predictors of shorter PFS. R-dex was successfully used for debulking before allogenic stem cell transplantation in 7 patients (12%). Serious (CTCAE grade III/IV) infections occurred in 27% of patients; 20% of patients developed steroid diabetes requiring temporary short-acting insulin.

CONCLUSIONS

Our results show that R-dex is an active and well-tolerated regimen for patients with relapsed/refractory CLL; however, major infections remain frequent despite combined antimicrobial prophylaxis.

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.

Glucocorticoid-induced apoptosis of healthy and malignant lymphocytes

Glucocorticoids exert a wide range of physiological effects, including the induction of apoptosis in lymphocytes. The progression of glucocorticoid-induced apoptosis is a multi-component process requiring contributions from both genomic and cytoplasmic signaling events. There is significant evidence indicating that the transactivation activity of the glucocorticoid receptor is required for the initiation of glucocorticoid-induced apoptosis. However, the rapid cytoplasmic effects of glucocorticoids may also contribute to the glucocorticoid-induced apoptosis-signaling pathway. Endogenous glucocorticoids shape the T-cell repertoire through both the induction of apoptosis by neglect during thymocyte maturation and the antagonism of T-cell receptor (TCR)-induced apoptosis during positive selection. Owing to their ability to induce apoptosis in lymphocytes, synthetic glucocorticoids are widely used in the treatment of haematological malignancies. Glucocorticoid chemotherapy is limited, however, by the emergence of glucocorticoid resistance. The development of novel therapies designed to overcome glucocorticoid resistance will dramatically improve the efficacy of glucocorticoid therapy in the treatment of haematological malignancies.