Bendamustine with or without rituximab in the treatment of relapsed chronic lymphocytic leukaemia: an Italian retrospective study

The role of antibody therapies in treating relapsed chronic lymphocytic leukemia: a review

INTRODUCTION

Chronic lymphocytic leukemia (CLL) is one of the most common types of leukemia in adult patients. The landscape of CLL therapy has changed in the last decades with the introduction of antibody-based therapies and novel targeted agents resulting in improved outcomes.

AREAS COVERED

This article describes the use of monoclonal antibodies, bispecific antibodies and antibody-drug conjugates in the treatment of relapsed and refractory CLL. The mechanism of action and clinical applications and safety of antibody-based therapies, both as monotherapy and in combination with other drugs, are discussed. A literature search was performed using PubMed, Web of Science, and Google Scholar for articles published in English. Additional relevant publications were obtained by reviewing the references from the chosen articles.

EXPERT OPINION

Antibody-based therapeutic strategies have drastically changed the treatment of CLL, as they have introduced the concept of boosting immune responses against tumor cells. While immunotherapy is generally effective, some treatment failure can occur due to antigen loss, mutation, or down-regulation, and this remains the main obstacle to cure. The development of novel antibody therapies, including their combinations with targeted drugs and bispecific antibodies, might help to reduce toxicity and improve efficacy.

How do CARs work?: Early insights from recent clinical studies targeting CD19

Second-generation chimeric antigen receptors (CARs) are powerful tools to redirect antigen-specific T cells independently of HLA-restriction. Recent clinical studies evaluating CD19-targeted T cells in patients with B-cell malignancies demonstrate the potency of CAR-engineered T cells. With results from 28 subjects enrolled by five centers conducting studies in patients with chronic lymphocytic leukemia (CLL) or lymphoma, some insights into the parameters that determine T-cell function and clinical outcome of CAR-based approaches are emerging. These parameters involve CAR design, T-cell production methods, conditioning chemotherapy as well as patient selection. Here, we discuss the potential relevance of these findings and in particular the interplay between the adoptive transfer of T cells and pre-transfer patient conditioning.

Combination of bendamustine and rituximab as front-line therapy for patients with chronic lymphocytic leukaemia: multicenter, retrospective clinical practice experience with 279 cases outside of controlled clinical trials

Recently, encouraging results in terms of safety and efficacy have been obtained using bendamustine-rituximab (BR) in untreated chronic lymphocytic leukaemia (CLL) patients enrolled in a phase II study. Here, we report a retrospective international multicenter study of CLL patients treated with BR as front-line therapy. The cohort included 279 patients with progressive CLL from 33 centers (29 Italian, 3 Israeli and 1 German) who received at least 1 cycle of BR as first-line treatment during the 2008-2014 period. The primary objective of this study was to evaluate the efficacy and safety of BR administered as front-line therapy, outside of controlled clinical trials. Median age was 70 years (range, 43-86 years); 62.4% were males and 35.8% had Binet stage C. Forty-two patients (15.2%) were unfit (cumulative illness rating scale [CIRS] score ≥7), and 140 (50.2%) had creatinine clearance ≤70 ml/min. Fluorescent in situ hybridisation analysis, available for 192 cases, showed that 21 (10.9%) had del11q and 18 (9.4%) del17p. The overall response rate (ORR) was 86.4%, with a complete remission rate of 28%. Patients with del17p had an ORR of 66.7%. After median follow-up of 24 months, the 2-year progression-free survival (PFS) was 69.9%; CIRS ≥7, immunoglobulin heavy-chain variable-region (IGHV) unmutated status, del17p and BR dose intensity <80% were independently associated with shorter PFS. Grade III or IV neutropenia, thrombocytopenia, and anaemia were observed in 25.9%, 15.4%, and 15.1% of patients, respectively. Twenty-four patients (8.6%) had severe infections. BR is also an effective and safe regimen for untreated CLL patients, outside of controlled clinical trials.

Safety and efficacy of different lenalidomide starting doses in patients with relapsed or refractory chronic lymphocytic leukemia: results of an international multicenter double-blinded randomized phase II trial

The objective of this study was to evaluate the safety and efficacy of different lenalidomide starting doses in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). CLL patients were randomized to receive lenalidomide at initial doses of 5, 10, or 15 mg/d (N = 103). Doses were escalated by 5 mg every 28-d up to a maximum of 25 mg/d; dose reductions in up to 5 mg decrements were permitted. The most common grade ≥3 adverse events (AEs) were neutropenia and thrombocytopenia. Ten patients died during therapy (four deaths considered as related to lenalidomide); 12 patients experienced second primary malignancies. The most common cause for treatment discontinuation was AEs. Overall response rates were similar across arms. Progression-free survival and overall survival rates were longer in patients who escalated treatment (to 15 or 20 mg/d) versus those who did not. Lower starting doses allowed subsequent dose escalation of lenalidomide while maintaining an acceptable tolerability profile in patients with relapsed/refractory CLL.

Bendamustine and rituximab in relapsed and refractory hairy cell leukemia

PURPOSE

To determine tolerability and for the first time explore efficacy of bendamustine-rituximab (BR) in multiply relapsed/refractory hairy cell leukemia (HCL), using two different dose levels of bendamustine.

EXPERIMENTAL DESIGN

Patients with HCL with ≥2 prior therapies requiring treatment received rituximab 375 mg/m(2) days 1 and 15 plus bendamustine 70 (n = 6) or 90 (n = 6) mg/m(2), days 1 and 2, for six cycles at 4-week intervals.

RESULTS

At 70 and 90 mg/m(2)/dose of bendamustine, overall response rate was 100%, with three (50%) and four (67%) complete remissions (CR) in each respective group. Minimal residual disease (MRD) was absent in 67% and 100% of CRs, respectively. All six without MRD remain in CR at 30 to 35 (median, 31) months of follow-up. Soluble CD22 and CD25 levels decreased with all responses, with median values decreasing from 17.7 and 42 ng/mL at baseline to undetectable and 2 ng/mL after CR, respectively (P < 0.001). Of 12 patients receiving 72 cycles of BR, the most common toxicities were hematologic, including thrombocytopenia (83%), lymphopenia (75%), leukopenia (58%), and neutropenia (42%). Grade III and IV hematologic toxicity included lymphopenia and thrombocytopenia (each 75%), leukopenia (58%), and neutropenia (25%). No significant dose-related differences were detected in response or toxicity.

CONCLUSION

BR has significant activity in HCL. Bendamustine at either 70 or 90 mg/m(2)/dose was highly effective in multiply relapsed/refractory HCL and could be considered for achieving durable CRs without MRD in patients after failure of standard therapies. As it was not dose-limiting, 90 mg/m(2)/dose was chosen for future testing.

Bendamustine in chronic lymphocytic leukemia: outcome according to different clinical and biological prognostic factors in the everyday clinical practice

Bendamustine proved to be effective for the treatment of chronic lymphocytic leukemia (CLL). However, the relationship between its activity with clinico-biological prognosticators has been addressed only in few studies. We retrospectively evaluated the efficacy of bendamustine, in a real-life contest, on 142 patients, median age 70 years, median number of previous regimens 2 (0-8, 13% previously untreated). Bendamustine was administered for a median number of 4 cycles, in 84% of cases with rituximab. Overall (ORR) and complete response (CRR) rates were 68 and 16.5%, respectively. Multivariate analysis demonstrated a relationship between ORR and number of prior treatments (OR 0.25, 95% CI 0.08-0.71; P = 0.009), del(17p) (OR 0.10, 95% CI 0.03-0.32; P < 0.001) and concomitant rituximab (OR 4.37, 95% CI 1.12-17.04; P = 0.033). The estimated 1- and 2-years overall survival (OS) and progression free survival (PFS) rates were 76, 61, 51, and 26%, respectively. Previous sensitivity to fludarabine (HR 0.36, 95% CI 0.16-0.82), response to bendamustine (HR 0.21, 95% CI 0.10-0.45), and del(17p) (HR 2.18, 95% CI 1.002-4.74) had a prognostic significance in multivariate analysis for PFS, while the number of previous therapies (HR 3.48, 95% CI 1.29-9.38; P = 0.014), concomitant use of rituximab (HR 0.32, 95% CI 0.11-0.93) and response to bendamustine (HR 0.22, 95% CI 0.07-0.66) were significant for OS. Side effects included grade 3-4 neutropenia, infections, thrombocytopenia and anemia which occurred in 40, 14, 14, and 10% of patients, respectively. These results confirm the activity and safety of bendamustine and rituximab combination even in patients with unfavorable clinical and biological features excluding del(17p).

Short communication: bendamustine-related hemolytic anemia in chronic lymphocytic leukemia

PURPOSE

Immune hemolytic anemia (IHA) may complicate the course of chronic lymphocytic leukemia (CLL), especially in patients with advanced disease, and as a complication of treatment with chlorambucil or fludarabine. Bendamustine, a novel agent with both alkylating and purine-analog properties, was approved in the USA for use in CLL in 2008. Since then, clinical data on its adverse events are accumulating. IHA related to bendamustine was seldom described and is thus reported and reviewed.

METHODS

We assessed five cases of CLL patients complicated by IHA, out of 31 treated with bendamustine for a relapse of their disease. Also reviewed are previous case reports in the literature.

RESULTS AND CONCLUSIONS

Bendamustine-related IHA is more common than suspected (16 %). No such cases were found in non-CLL patients. Personal history of fludarabine-triggered AIHA may be a risk factor for this complication (recorded in 4/5 patients, 80 %). The mechanism is thought to be related to the loss of T cell regulatory control as described for other agents. Physicians using bendamustine for the treatment for CLL should be aware of this complication.

Phase II study of lenalidomide and rituximab as salvage therapy for patients with relapsed or refractory chronic lymphocytic leukemia

PURPOSE

Lenalidomide is an immunomodulatory drug active as salvage therapy for chronic lymphocytic leukemia (CLL). We combined lenalidomide with rituximab to improve response rates in patients with relapsed or refractory CLL.

PATIENTS AND METHODS

Fifty-nine adult patients (age 42 to 82 years) with relapsed or refractory CLL were enrolled onto a phase II study of lenalidomide and rituximab. Patients had received prior fludarabine-based therapy or chemoimmunotherapy. Rituximab (375 mg/m(2) intravenously) was administered weekly during cycle one and on day 1 of cycles three to 12. Lenalidomide was started on day 9 of cycle one at 10 mg orally and administered daily continuously. Each cycle was 28 days. Rituximab was administered for 12 cycles; lenalidomide could continue indefinitely if patients benefitted clinically.

RESULTS

The overall response rate was 66%, including 12% complete responses and 12% nodular partial remissions. Time to treatment failure was 17.4 months. Median overall survival has not been reached; estimated survival at 36 months is 71%. The most common grade 3 or 4 toxicity was neutropenia (73% of patients). Fourteen patients (24%) experienced a grade 3 to 4 infection or febrile episode. There was one episode of grade 3 tumor lysis; one patient experienced renal failure during the first cycle of therapy, and one venous thromboembolic event occurred during the study.

CONCLUSION

The combination of lenalidomide and rituximab is active in patients with recurrent CLL and warrants further investigation.

Retreatment with bendamustine-containing regimens in patients with relapsed/refractory chronic lymphocytic leukemia and indolent B-cell lymphomas achieves high response rates and some long lasting remissions

Bendamustine and bendamustine/rituximab combinations have shown high efficacy in relapsed/refractory chronic lymphocytic leukemia (CLL) and indolent B-cell malignancies (non-Hodgkin lymphoma, NHL). No data exist about bendamustine retreatment after relapse, concerning efficacy and toxicity in this patient population. Eighty-eight outpatients (57 patients with CLL, 31 patients with NHL) who had previously been treated with bendamustine were retreated with a bendamustine regimen. Treatment consisted of bendamustine (B) or bendamustine + mitoxantrone (BM) or bendamustine + rituximab (BR) or bendamustine + mitoxantrone + rituximab (BMR). Median age was 72 years (50-88). A reversible grade 3 or 4 leukocytopenia or thrombocytopenia was observed in 24% and 13%, respectively. The overall response rate (ORR) was 76% (7% complete remission [CR], 69% partial remission [PR]) with 77% (6% CR, 71% PR) in CLL and 71% (8% CR, 63% PR) in NHL. ORR according to regimen was as follows: B: 57% (14% CR, 43% PR), BM: 70% (4% CR, 66% PR), BR: 55% (10% CR, 45% PR), BMR: 84% (7% CR, 78% PR). Bendamustine retreatment is feasible and achieves high response rates and some long lasting remissions.

Rituximab, ofatumumab and other monoclonal anti-CD20 antibodies for chronic lymphocytic leukaemia

BACKGROUND

Chronic lymphocytic leukaemia (CLL) accounts for 25% of all leukaemias and is the most common lymphoid malignancy in western countries. Standard treatments include mono- or polychemotherapies, usually combined with monoclonal antibodies such as rituximab or alemtuzumab. However, the impact of these agents remains unclear, as there are hints for increased risk of severe infections.

OBJECTIVES

The objectives of this review are to provide an evidence-based answer regarding the clinical benefits and harms of monoclonal anti-CD20 antibodies (such as rituximab, ofatumumab, GA101) compared to no further therapy or to other anti-leukaemic therapies in patients with CLL, irrespective of disease status.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 12, 2011), MEDLINE (from January 1990 to 4 January 2012), and EMBASE (from 1990 to 20 March 2009) as well as conference proceedings (American Society of Hematology, American Society of Clinical Oncology, European Hematology Association and European Society of Medical Oncology) for randomised controlled trials (RCTs).

SELECTION CRITERIA

We included RCTs examining monoclonal anti-CD20 antibodies compared to no further therapy or to anti-leukaemic therapy such as chemotherapy or monoclonal antibodies in patients with newly diagnosed or relapsed CLL.

DATA COLLECTION AND ANALYSIS

We used hazard ratios (HR) as effect measures for overall survival (OS), progression-free survival (PFS) and time to next treatment, and risk ratios (RR) for response rates, treatment-related mortality (TRM) and adverse events (AEs). Two review authors independently extracted data and assessed quality of trials.

MAIN RESULTS

We screened a total of 1150 records. Seven RCTs involving 1763 patients were identified, but only five could be included in the two separate meta-analyses we performed. We judged the overall the quality of these trials as moderate to high. All trials were randomised and open-label studies. However, two trials were published as abstracts only, therefore we were unable to assess the potential risk of bias for these trials in detail.Three RCTs (N = 1421) assessed the efficacy of monoclonal anti-CD20 antibodies (i.e. rituximab) plus chemotherapy compared to chemotherapy alone. The meta-analyses showed a statistically significant OS (HR 0.78, 95% confidence interval (CI) 0.62 to 0.98, P = 0.03, the number needed to treat for an additional beneficial effect (NNTB) was 12) and PFS (HR 0.64, 95% CI 0.55 to 0.74, P < 0.00001) advantage for patients receiving rituximab. In the rituximab-arm occurred more AEs, World Health Organization (WHO) grade 3 or 4 (3 trials, N = 1398, RR 1.15, 95% CI 1.08 to 1.23, P < 0.0001; the number needed to harm for an additional harmful outcome (NNTH) was 9), but that did not lead to a statistically significant difference regarding TRM (3 trials, N = 1415, RR 1.19, 95% CI 0.70 to 2.01, P = 0.52).Two trials (N = 177) evaluated rituximab versus alemtuzumab. Neither study reported OS or PFS. There was no statistically significant difference between arms regarding complete response rate (CRR) (RR 1.21, 95% CI 0.94 to 1.58, P = 0.14) or TRM (RR 0.31, 95% CI 0.06 to 1.51, P = 0.15). However, the CLL2007FMP trial was stopped early owing to an increase in mortality in the alemtuzumab arm. More serious AEs occurred in this arm (43% with alemtuzumab versus 22% with rituximab; P = 0.006).Two trials assessed different dosages or time schedules of monoclonal anti-CD20 antibodies. One trial (N = 104) evaluated two different rituximab schedules (concurrent arm: fludarabine plus rituximab (Flu-R) plus rituximab consolidation versus sequential arm: fludarabine alone plus rituximab consolidation). The comparison of the concurrent versus sequential regimen of rituximab showed a statistically significant difference of the CRR with 33% in the concurrent-arm and 15% in the sequential-arm (P = 0.04), that did not lead to statistically significant differences regarding OS (HR 1.14, 95% CI 0.20 to 6.65, P = 0.30) or PFS (HR 0.96, 95% CI 0.43 to 2.15, P = 0.11). Furthermore results showed no differences in occurring AEs, except for neutropenia, which was more often observed in patients of the concurrent arm. The other trial (N = 61) investigated two different dosages (500 mg and 1000 mg) of ofatumumab in addition to FluC. The arm investigating ofatumumab did not assess OS and a median PFS had not been reached owing to the short median follow-up of eight months. It showed no statistically significant differences between arms regarding CRR (32% in the FCO500 arm versus 50% in the FCO1000 arm; P = 0.10) or AEs (anaemia, neutropenia, thrombocytopenia).

AUTHORS' CONCLUSIONS

This meta-analysis showed that patients receiving chemotherapy plus rituximab benefit in terms of OS as well as PFS compared to those with chemotherapy alone. Therefore, it supports the recommendation of rituximab in combination with FluC as an option for the first-line treatment as well as for the people with relapsed or refractory CLL. The available evidence regarding the other assessed comparisons was not sufficient to deduct final conclusions.