Bendamustine/Mitoxantrone/Rituximab (BMR): A Very Effective, Well Tolerated Outpatient Chemoimmunotherapy for Relapsed and Refractory CD20-positive Indolent Malignancies. Final Results of a Pilot Study

A new case of trisomy 5 with complex karyotype abnormalities in B-cell prolymphocytic leukemia: a case study

Background

The B-cell prolymphocytic leukemia (B-PLL) diagnosis is challenging due to the superposition with mature B-cell leukemia and/or lymphoma.

Objective

An insight case study of trisomy 5 with complex karyotype abnormalities in B-cell prolymphocytic leukemia.

Subject and methods

A 72-year-old man was referred to the Hematology Department, Qilu Hospital, Shandong University, because of persistent fever (10 days) and lymphocytosis. A detailed diagnostic methods including complete blood count, bone marrow aspiration, flow cytometry, conventional karyotype analysis, fluorescence in situ hybridization (FISH), quantitative real-time polymerase chain reaction (qRT-PCR), next-generation sequencing technology (NGS) used to detect 41 kinds of mutant genes related to hematological malignancies were conducted and reasonable therapeutic regimens including emergent leukapheresis accompanied by basification of urine and hydrotherapy, followed by a regimen of cyclophosphamide and dexamethasone.

Results

Subject white blood cell count was 143.43 × 109/L, and 56% prolymphocytes. He did not show lymphadenopathy but splenomegaly. Immunophenotyping of prolymphocytes was CD5(+low), CD10(−), CD11c(−), CD19(+), CD20(+), cCD22(+), CD23(−), cCD79a(+), CD79b(+), FMC7(±), CD43(−), CD3(−), CD56(−), CD103(−), HLA-DR(+), and Lambda(+). R-banding and FISH revealed that leukemia cells carried extra chromosome 5. Considering the rare occurrence of trisomy 5 found in prolymphocytic leukemia, especially in Asians, with rapid disease progression. We know that median survival of B-PLL is three years after diagnosis, while survival time of this patient was only 1 month.

Conclusion

This study could provide the firsthand materials for precision, medicine and mechanism research in cytogenetics and molecular biology. It inferred that trisomy 5 might be a poor prognosis indicator, providing directions for clinical practice in the foreseeable future.

A Novel Treatment With Obinutuzumab-Chlorambucil in a Patient With B-Cell Prolymphocytic Leukemia: A Case Report and Review of the Literature

We report the case of a patient with B-cell prolymphocytic leukemia who was successfully treated with the novel humanized monoclonal antibody obinutuzumab. This patient was previously treated with the combination of rituximab and bendamustine and had recurrent infusion reactions. Her treatment with rituximab and bendamustine was discontinued when she developed disease progression after 3 cycles of therapy. She was then treated with obinutuzumab 1000 mg on day 1 of every cycle and chlorambucil 0.5 mg/kg on days 1 and 15 every 28 days to which she had greater tolerability. After 4 cycles of treatment, she had resolution of her clinical symptoms, massive splenomegaly, and normalization of her white blood cell count.

Sequential Kinase Inhibition (Idelalisib/Ibrutinib) Induces Clinical Remission in B-Cell Prolymphocytic Leukemia Harboring a 17p Deletion

B-cell prolymphocytic leukemia (B-PLL) is a rare lymphoid neoplasm with an aggressive clinical course. Treatment strategies for B-PLL remain to be established, and, until recently, alemtuzumab was the only effective therapeutic option in patients harboring 17p deletions. Herein, we describe, for the first time, a case of B-cell prolymphocytic leukemia harboring a 17p deletion in a 48-year-old man that was successfully treated sequentially with idelalisib-rituximab/ibrutinib followed by allogeneic hematopoietic stem cell transplant (allo-HSCT). After 5 months of therapy with idelalisib-rituximab, clinical remission was achieved, but the development of severe diarrhea led to its discontinuation. Subsequently, the patient was treated for 2 months with ibrutinib and the quality of the response was maintained with no severe adverse effects reported. A reduced-intensity conditioning allo-HSCT from a HLA-matched unrelated donor was performed, and, thereafter, the patient has been in complete remission for 10 months now. In conclusion, given the poor prognosis of B-PLL and the lack of effective treatment modalities, the findings here suggest that both ibrutinib and idelalisib should be considered as upfront therapy of B-PLL and as a bridge to allo-HSCT.

Management of prolymphocytic leukemia

B-cell (B-PLL) and T-cell (T-PLL) prolymphocytic leukemias are rare, poor-prognosis lymphoid neoplasms with similar presentation characterized by symptomatic splenomegaly and lymphocytosis. They can be distinguished from each other and from other T- and B-cell leukemias by careful evaluation of morphology, immunophenotyping, and molecular genetics. The clinical behavior is typically aggressive, although a subset of patients may have an indolent phase of variable length. First-line therapy for T-PLL is with intravenous alemtuzumab and for B-PLL is with combination purine analog-based chemo-immunotherapy. New B-cell receptor inhibitors, such as ibrutinib and idelalisib, may have a role in the management of B-PLL, especially for the patients harboring abnormalities of TP53. Allogenic stem cell transplantation should still be considered for eligible patients and may be the only current therapy capable of delivering a cure. In the past few years, many of the molecular mechanisms underlying disease pathogenesis and progression have been revealed and are likely to lead to the development of novel targeted approaches.

Determination and characterization of two degradant impurities in bendamustine hydrochloride drug product

Bendamustine hydrochloride is an alkylating antitumor agent with a good efficacy in the treatment of chronic lymphocytic leukemia (CLL) and B-cell non-Hodgkin's lymphoma (B-NHL). Under the stressed conditions, two degradant impurities in bendamustine hydrochloride drug product were detected by high-performance liquid chromatography. These two degradant impurities were isolated from preparative liquid chromatography, and were further characterized using Q-TOF/MS and nuclear magnetic resonance (NMR). Based on the MS and NMR spectral data, they were characterized as 4-[5-(2-chloro-ethylamino)-1-methyl-1H-benzoimidazol-2-yl] butyric acid hydrochloride (impurity-A) and 4-{5-[[2-(4-{5-[bis-(2-chloroethyl) amino]-1-methyl-1H-benzoimidazol-2-yl}-butyryloxy)-ethyl]-(2-chloroethyl)amino]-1-methyl-3a, 7a-dihydro-1H-benzoimidazol-2-yl} butyric acid hydrochloride (impurity-B). Isolation, structural elucidation of these two impurities by spectral data (Q-TOF/MS, (1)H NMR, (13)C NMR, D2O exchange NMR and two-dimensional NMR) and the probable formation mechanism of the impurities were discussed.

Management of prolymphocytic leukemia

B-cell (B-PLL) and T-cell (T-PLL) prolymphocytic leukemias are rare, poor-prognosis lymphoid neoplasms with similar presentation characterized by symptomatic splenomegaly and lymphocytosis. They can be distinguished from each other and from other T- and B-cell leukemias by careful evaluation of morphology, immunophenotyping, and molecular genetics. The clinical behavior is typically aggressive, although a subset of patients may have an indolent phase of variable length. First-line therapy for T-PLL is with intravenous alemtuzumab and for B-PLL is with combination purine analog-based chemo-immunotherapy. New B-cell receptor inhibitors, such as ibrutinib and idelalisib, may have a role in the management of B-PLL, especially for the patients harboring abnormalities of TP53. Allogenic stem cell transplantation should still be considered for eligible patients and may be the only current therapy capable of delivering a cure. In the past few years, many of the molecular mechanisms underlying disease pathogenesis and progression have been revealed and are likely to lead to the development of novel targeted approaches.

The role of chemotherapy in managing chronic lymphocytic leukemia: optimizing combinations with targeted therapy

For many years, alkylating agents were the standard treatment for chronic lymphocytic leukemia (CLL). The advent of purine analogs improved response rates, but not overall survival, and although the monoclonal antibody rituximab is generally active against B-cell malignancies, it has demonstrated limited benefits as monotherapy for the treatment of CLL. However, specific combinations of chemotherapy, antibodies and targeted therapies have demonstrated additive or synergistic activity in CLL cells and deliver substantial clinical benefits. A greater understanding of the actions of chemotherapies and targeted agents on cellular pathways will advance the development of rationally designed combinations corresponding to individual patients' disease profiles.

B- and T-cell prolymphocytic leukemia: antibody approaches

B- and T-cell subtypes of prolymphocytic leukemia (PLL) are rare, aggressive lymphoid malignancies with characteristic morphologic, immunophenotypic, cytogenetic, and molecular features. Prognosis for these patients remains poor, with short survival times and no curative therapy. The advent of mAbs has improved treatment options. In B-PLL, rituximab-based combination chemoimmunotherapy is effective in fitter patients. TP53 abnormalities are common and, as for chronic lymphocytic leukemia, these patients should generally be managed using an alemtuzumab-based therapy. Currently, the best treatment for T-PLL is IV alemtuzumab, which has resulted in very high response rates of more than 90% when given as frontline treatment and a significant improvement in survival. Consolidation of remissions with autologous or allogeneic stem cell transplantation further prolongs survival times, and the latter may offer potential cure. The role of allogeneic transplantation with nonmyeloablative conditioning needs to be explored further in both T- and B-PLL to broaden the patient eligibility for what may be a curative treatment.

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.

Bendamustine for patients with indolent B cell lymphoid malignancies including chronic lymphocytic leukaemia

BACKGROUND

Indolent B cell lymphoid malignancies include follicular lymphoma, small lymphocytic lymphoma, mantle cell lymphoma, lymphoplasmacytic lymphoma and marginal zone lymphomas. Chronic lymphocytic leukaemia (CLL) is a lymphoid malignancy similar to small lymphocytic lymphoma (SLL) in its leukaemic phase.Indolent lymphoid malignancies including CLL are characterised by slow growth, a high initial response rate and a relapsing and progressive disease course. Advanced-stage indolent B cell lymphoid malignancies are often incurable. If symptoms or progressive disease occur, chemotherapy plus rituximab is indicated. No chemotherapy regimen has been shown to improve overall survival compared to a different regimen.Bendamustine is efficacious in the treatment of patients with indolent B cell lymphoid malignancies. A number of randomised controlled trials have examined the effect of bendamustine compared to other chemotherapy regimens in these patients. Improved disease control with no survival benefit is shown.

OBJECTIVES

To evaluate the efficacy of bendamustine therapy for patients with indolent B cell lymphoid malignancies including CLL.

SEARCH METHODS

We electronically searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 2), MEDLINE (1966 to May 2012), EMBASE (1974 to November 2011), LILACS (1982 to May 2012), databases of ongoing trials (accessed 30 April 2012) and relevant conference proceedings. We searched references of identified trials and contacted the first author of each included trial.

SELECTION CRITERIA

Randomised controlled trials that compared a bendamustine-containing regimen to other chemotherapy with or without immunotherapy.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from included trials. We estimated and pooled hazard ratios (HR) and risk ratios (RR) with 95% confidence intervals (CI).

MAIN RESULTS

We included five trials randomising 1343 adult patients in the systematic review. Allocation and blinding were unclear in three trials and adequate in two. Incomplete outcome data and selective reporting were adequate in all trials. Trials varied in the type of lymphoid malignancy, bendamustine regimen and the comparator regimen. In the three trials that included patients with follicular lymphoma, mantle cell lymphoma and other indolent lymphomas the comparator treatment was cyclophosphamide, a combination of cyclophosphamide, vincristine, doxorubicin and prednisone, and fludarabine. Two trials included only patients with CLL and compared bendamustine to chlorambucil, and to fludarabine. We did not conduct a meta-analysis due to the clinical heterogeneity among trials. Bendamustine had no statistically significant effect on the overall survival of patients with indolent B cell lymphoid malignancies in any of the included trials (trials of moderate quality). Progression-free survival was statistically significantly improved with bendamustine treatment compared to other chemotherapy in three of the four trials that reported on it. One trial demonstrated a non statistically significant improvement of PFS. The risk of grade 3 or 4 adverse events was similar when bendamustine was compared to CHOP and fludarabine, and higher when compared to chlorambucil. Compared to chlorambucil quality of life was unaffected by bendamustine treatment (one trial, no meta-analysis).

AUTHORS' CONCLUSIONS

As none of the currently available chemotherapeutic protocols for induction therapy in indolent B cell lymphoid malignancies confer a survival benefit and due to the improved progression-free survival in each of the included trials, and a similar rate of grade 3 or 4 adverse events, bendamustine may be considered for the treatment of patients with indolent B cell lymphoid malignancies. However, the unclear effect on survival and the higher rate of adverse events compared to chlorambucil in patients with CLL/SLL does not support the use of bendamustine for these patients.The effect of bendamustine combined with rituximab should be evaluated in randomised clinical trials with more homogenous populations and outcomes for specific subgroups of patients by type of lymphoma should be reported. Any future trial should evaluate the effect of bendamustine on quality of life.

Current status of targeted therapies for mantle cell lymphoma

Mantle cell lymphoma (MCL) is a type of non-Hodgkin's lymphoma (NHL) with treatment outcomes that have historically been poorer than those observed with other NHL subtypes. Patients typically present with advanced-stage disease and frequent extranodal involvement; the median age at diagnosis is >60 years. Recent improvements in progression-free and overall survival have been observed with more dose-intensive strategies, although at least half of patients diagnosed with MCL are not eligible for such treatment approaches based on age and co-morbidities. In addition, therapy options for relapsed MCL are limited. Only bortezomib is approved for treatment of relapsed MCL in the US. Development of targeted therapy approaches to minimize toxicities while preserving anti-neoplastic properties is of particular importance in MCL. Multiple ongoing studies are attempting to build on the known efficacy of bortezomib by evaluating combination regimens with other targeted agents or cytotoxic chemotherapy. The mammalian target of rapamycin (mTOR) inhibitor temsirolimus has known activity in MCL, making this an attractive class of agents for further investigation in combination regimens. Rituximab and other monoclonal antibodies are being evaluated for novel roles in MCL treatment, including as maintenance therapy. Other classes of drugs being investigated in MCL are immunomodulatory agents, inhibitors of the phosphoinositide 3-kinase/Akt and B-cell receptor signalling pathways, and inhibitors of bcl-2 and histone deacetylase. Although many of the agents appear to have modest single-agent activity, the favourable toxicity profile of many agents will make them best suited for incorporation into combination regimens.

Bendamustine for treatment of chronic lymphocytic leukemia

INTRODUCTION

Chronic lymphocytic leukemia (CLL) often has an extended disease course. With a median age at diagnosis of 72 years, newer treatment options with less toxicity than standard nucleoside analogue-based regimens are needed. Historically, few therapy options are available once CLL has become refractory to nucleoside analogues. Bendamustine has emerged as a feasible therapy for older and less fit CLL patients, with clinical efficacy in previously untreated and refractory CLL.

AREAS COVERED

This paper reviews several of the pivotal clinical trials that established the clinical activity of bendamustine in previously untreated and relapsed/refractory CLL. The toxicity profile of bendamustine, primarily myelosuppression and infections, is reviewed and compared across different CLL populations. A review of the clinical data focuses on potential explanations for differences in response rates and duration of remission reported across studies and how this may impact the development of therapies for CLL.

EXPERT OPINION

Bendamustine is a valuable new agent for the management of CLL. Ongoing clinical trials are comparing bendamustine with standard CLL regimens in untreated disease, and investigating bendamustine combinations with novel targeted therapies and monoclonal antibodies. These studies will help to define the optimal role for bendamustine in CLL management.

Treatment of relapsed or refractory chronic lymphocytic leukemia

BACKGROUND

Recent advances in the treatment of chronic lymphocytic leukemia (CLL) have moved beyond the traditional use of alkylating agents and purine analogs into regimens combining these two chemotherapy classes with monoclonal antibodies.

METHODS

This article reviews treatments options for patients with relapsed or refractory CLL.

RESULTS

Several studies have investigated novel agents in treating patients with 17p deletion, TP53 mutation, and fludarabine-refractory CLL, as well as patients with suboptimal response to intense treatment. These investigational agents include rituximab, alemtuzumab, ofatumumab, bendamustine, high-dose methylprednisolone, lenalidomide, lumiliximab, cyclin-dependent kinase inhibitors, small modular immunopharmaceuticals, Bcl-2 inhibitors, and histone deacetylase inhibitors. While these newer drugs and combination therapies have shown promise as treatment options for CLL, additional studies are needed to determine the immunosuppression, toxicities, and infections associated with their use.

CONCLUSIONS

Despite improvement in initial overall response rates, most patients relapse and require further treatment. CLL remains incurable with standard therapies due to development of disease refractoriness. As such, novel approaches such as those noted above warrant continued research to improve outcomes for patients with CLL.

How I treat prolymphocytic leukemia

T- and B-cell subtypes of prolymphocytic leukemia (PLL) are rare, aggressive lymphoid malignancies with characteristic morphologic, immunophenotypic, cytogenetic, and molecular features. Recent studies have highlighted the role of specific oncogenes, such as TCL-1, MTCP-1, and ATM in the case of T-cell and TP53 mutations in the case of B-cell prolymphocytic leukemia. Despite the advances in the understanding of the biology of these conditions, the prognosis for these patients remains poor with short survival and no curative therapy. The advent of monoclonal antibodies has improved treatment options. Currently, the best treatment for T-PLL is intravenous alemtuzumab, which has resulted in very high response rates of more than 90% when given as first-line treatment and a significant improvement in survival. Consolidation of remissions with autologous or allogeneic stem cell transplantation further prolongs survival, and the latter may offer potential cure. In B-PLL, rituximab-based combination chemo-immunotherapy is effective in fitter patients. TP53 abnormalities are common and, as for chronic lymphocytic leukemia, these patients should be managed using an alemtuzumab-based therapy. The role of allogeneic transplant with nonmyeloablative conditioning needs to be explored further in both T- and B-cell PLL to broaden the patient eligibility for what may be a curative treatment.

Bendamustine HCL for the treatment of relapsed indolent non-Hodgkin's lymphoma

Bendamustine is an alkylating agent which also shows properties of a purine analog. Because of its unique mechanism of action it shows activity in relapsed indolent lymphomas which are resistant to alkylating agents, purine analogs, and rituximab. Bendamustine has a favorable toxicity profile causing no alopecia and only a moderate hematotoxicity and gastrointestinal toxicity. Combinations of bendamustine with mitoxantrone and rituximab and with rituximab alone have been shown to be highly active in relapsed/refractory indolent lymphomas and mantle cell lymphomas achieving long lasting complete remissions. Because of only moderate toxicity these combinations can be applied safely in elderly patients who can be treated in an outpatient setting.

Bendamustine: safety and efficacy in the management of indolent non-hodgkins lymphoma

Bendamustine (Treanda, Ribomustin) was recently approved by the US Food and Drug Administration (FDA) for treatment of patients with rituximab refractory indolent lymphoma and is expected to turn into a frontline therapy option for indolent lymphoma. This compound with amphoteric properties was designed in the former Germany Democratic Republic in 1960s and re-discovered in 1990s with multiple successive well-designed studies. Bendamustine possesses a unique mechanism of action with potential antimetabolite properties, and only partial cross-resistance with other alkylators. Used in combination with rituximab in vitro, bendamustine shows synergistic effects against various leukemia and lymphoma cell lines. In clinical studies, bendamustine plus rituximab is highly effective in patients with relapsed-refractory indolent lymphoma, inducing remissions in 90% or more and a median progression-free survival of 23-24 months. The optimal dosing and schedule of bendamustine administration is largely undecided and varies among studies. Results of ongoing trials and dose-finding studies will help to further help ascertain the optimal place of bendamustine in the management of indolent NHL.

Bendamustine in chronic lymphocytic leukemia and non-Hodgkin's lymphoma

Bendamustine (Treanda(®); Pharmachemie BV, The Netherlands for Cephalon, Inc., PA, USA) is a unique cytotoxic agent with both alkylating and antimetabolite properties. A growing body of evidence demonstrates its efficacy in a number of hematologic malignancies, and as such, it has been US FDA approved for the treatment of chronic lymphocytic leukemia and non-Hodgkin's lymphoma that has not responded to, or progressed within 6 months of, a rituximab-based regimen. Bendamustine has efficacy both as a single agent as well as in combination with other chemotherapeutics and immunotherapeutics. Here, we will discuss in the detail the molecular properties, clinical efficacy and safety profile of bendamustine.

Bendamustine: something old, something new

BACKGROUND

Bendamustine (Treanda, Ribomustin) is a water-soluble, bifunctional chemotherapeutic agent that also has potential antimetabolite properties and only partial cross-resistance with other alkylators. Designed in 1963 and re-discovered in 1990s, this drug's unique mechanism of action and favorable side-effect profile promise a major role in the management of lymphoproliferative disorders. Bendamustine has been designated as an orphan drug in the United States, conferring prolonged market exclusivity.

OBJECTIVE

This article provides a comprehensive review of the data on efficacy and toxicity from trials investigating the use of bendamustine for the treatment of lymphoproliferative neoplasms. The pharmacology, pharmacokinetics, and pre-clinical studies with bendamustine are also reviewed.

METHODS

MEDLINE and Pubmed databases (1970-2010) were searched using the terms bendamustine, bendamustin, Treanda, Ribomustin, SDX-105, IMET-3393, and Cytostasan. All relevant articles were reviewed and references screened for additional articles. The databases of the American Society of Hematology (2004-2009) and the American Society of Clinical Oncology (1995-2009) were also searched for relevant abstracts.

RESULTS

Bendamustine induces a remission in more than three-fourths of patients with rituximab-refractory indolent B cell non-Hodgkin lymphoma (NHL). Combined with rituximab in vitro, bendamustine shows synergistic effects against various leukemia and lymphoma cell lines. Clinical trials supporting these results show that bendamustine plus rituximab is highly effective in patients with relapsed-refractory indolent lymphoma, inducing remissions in 90% or more and a median progression-free survival of 23-24 months. Bendamustine has been reasonably well tolerated in clinical trials with low propensity to induce alopecia.

CONCLUSIONS

Combination of bendamustine and rituximab has the potential to become a new standard first-line treatment option for patients with FL, MCL, and indolent lymphomas. Results of ongoing trials will help to further elucidate the optimal role of bendamustine in indolent NHL.

Bendamustine for the treatment of chronic lymphocytic leukemia and rituximab-refractory, indolent B-cell non-Hodgkin lymphoma

BACKGROUND

Bendamustine is a mechlorethamine derivative with a purine-like benzimidazole ring, which may enhance its clinical efficacy. Bendamustine was approved by the US Food and Drug Administration (FDA) for the treatment of chronic lymphocytic leukemia (CLL) in March 2008 and for the treatment of rituximab-refractory, indolent B-cell non-Hodgkin lymphoma (NHL) in October 2008.

OBJECTIVE

This article reviews the pharmacologic and pharmacodynamic properties of bendamustine, together with data on efficacy and toxicity from trials investigating the use of bendamustine for the treatment of various hematologic malignancies, including CLL, NHL, and multiple myeloma (MM).

METHODS

MEDLINE and International Pharmaceutical Abstracts (1970-April 15, 2009) were searched using the terms bendamustine, bendamustin, Treanda, Ribomustin, SDX-105, IMET-3393, and Cytostasan. References from relevant articles were also reviewed for additional sources and material. The databases of the American Society of Hematology (2004-2008) and the American Society of Clinical Oncology (1995-2008) were searched for relevant abstracts.

RESULTS

Bendamustine is a mechlorethamine derivative with structural similarity to chlorambucil and other drugs from the nitrogen mustard class, as well as a benzimidazole ring, which may act as an antagonist to purines and amino acids. It has good oral bioavailability but has been studied almost exclusively in the intravenous formulation. It undergoes extensive first-pass metabolism by cytochrome P450 1A2 to active metabolites gamma-hydroxy bendamustine and N-desmethyl-bendamustine, but clinical activity appears to be associated primarily with the parent compound. The t(1/2) of bendamustine is approximately 40 minutes. While bendamustine has 2 moieties with possible antitumor effect, it is unclear to what extent the benzimidazole ring enhances the efficacy of the drug. Numerous studies including in vitro assays have reported, however, that bendamustine has little cross-resistance with other alkylating agents and remains active even in extensively pretreated patients. FDA approval for use in CLL was based on findings from a randomized, open-label, Phase III study comparing bendamustine with chlorambucil as single-agent therapy in treatmentnaive patients with CLL (Binet stage B or C). Bendamustine was administered intravenously at a dose of 100 mg/m2 on days 1 and 2, while chlorambucil was administered orally at 0.8 mg/kg daily, both over 4-week cycles for up to 6 cycles. At interim analysis (the data used for FDA approval), bendamustine was associated with a greater overall response (68% vs 39%; P < 0.001), median progression-free survival (21.7 vs 9.3 months; P < 0.001) and median duration of remission (18.9 vs 6.1 months; P < 0.001) compared with chlorambucil. FDA approval for rituximabrefractory, indolent B-cell NHL followed a Phase III, open-label, single-arm study evaluating bendamustine monotherapy in patients who did not respond to rituximab or had progressive disease within 6 months of rituximab therapy. Bendamustine 120 mg/m(2) was administered intravenously on days 1 and 2 of a 21-day cycle for up to 8 cycles. At interim analysis, the overall response rate was 84%, including 29% complete response. The median progression-free survival was 9.7 months. The efficacy of bendamustine has also been reported in the treatment of MM in clinical studies, and bendamustine has been approved in Europe for treating MM, NHL, CLL, breast cancer, and Hodgkin lymphoma. Dose-limiting toxicity is primarily hematologic. Treatment-associated infections have been reported in some studies; however, nonhematologic adverse events have rarely been dose limiting. The most common nonhematologic adverse events include fatigue, nausea, xerostomia, and pyrexia.

CONCLUSIONS

Bendamustine is a mechlorethamine derivative with a purine-like benzimidazole ring, which may enhance its clinical efficacy. It has been approved in the United States for the treatment of CLL and rituximab-refractory, indolent B-cell NHL. It has been approved in Europe for use in other malignancies, and clinical studies have reported activity in MM.

The role of bendamustine in the treatment of indolent non-Hodgkin lymphoma

There is no consensus on recommendations for the treatment of relapsed and refractory indolent non-Hodgkin lymphoma (NHL). Bendamustine hydrochloride (bendamustine) has recently been approved for treatment of these patients. Bendamustine is a uniquely structured alkylating agent that lacks cross-resistance with other alkylators. This agent has a high degree of activity against a variety of tumor cell lines. Clinically, bendamustine has demonstrated activity against indolent NHL, chronic lymphocytic lymphoma, multiple myeloma and mantle cell lymphoma. Moreover, studies have validated its activity in patients with indolent NHL who are resistant to purine analogs and rituximab. The cytotoxic activity of bendamustine has been shown to be synergistic with rituximab in hematological malignancies. The incidence of alopecia is significantly less than with other alkylating agents. Myelosuppression is the major toxicity associated with bendamustine.

Chronic lymphocytic leukemia: treatment options for patients with refractory disease

Patients with purine analogue-refractory chronic lymphocytic leukemia (CLL) have short survival and limited treatment options. Defining the best salvage strategies for this population is challenging, because limited data are available from clinical trials, and because studies have enrolled mixed populations (patients with recurrent and refractory disease or patients with refractory disease and Richter transformation). Moreover, patients with refractory CLL have a high incidence of unfavorable molecular and clinical features, such as high-risk genomic profiles, unmutated immunoglobulin heavy-chain genes, expression of zeta-chain-associated protein kinase 70, and bulky lymphadenopathies. These patients are also severely immunosuppressed because of the underlying disease and the treatments received, and experience a high rate of infectious complications that pose an additional difficulty in selecting treatment. Despite these challenges, in parallel with better characterizations of the biologic features of refractory CLL, the number of available treatment modalities for this population has increased. Several chemoimmunotherapy combinations have been developed, and novel agents with a different mechanism of action are being investigated in clinical trials. Furthermore, allogeneic stem cell transplantation with nonmyeloablative conditioning regimens is a therapeutic strategy that is increasingly offered to patients with refractory CLL.

Bendamustine in the treatment of chronic lymphocytic leukemia

Bendamustine is a cytotoxic agent that combines alkylating and antimetabolite effects. It has shown promising efficacy in a number of hematological cancers and, hence, is being investigated in patients with chronic lymphocytic leukemia (CLL), which is the most common form of adult leukemia in the Western world. Phase I/II trials with bendamustine as single-agent therapy in CLL have shown overall response rates of 56-93% and complete response rates of 7-29%. Preliminary data from a Phase III trial comparing bendamustine and chlorambucil (an agent widely used in the current treatment of CLL) have shown significantly higher response rates with bendamustine. Bendamustine has also shown activity in CLL when combined with mitoxantrone, rituximab or both. The principal toxicities associated with bendamustine are hematological, mainly leukopenia.

Bendamustine: a new look at an old drug

Alkylating agents form the basis of most combination treatment regimens for low-grade lymphoproliferative disorders. Bendamustine is a unique alkylating agent that has distinctive preclinical activity in cell lines resistant to other alkylators. Furthermore, clinical activity has been demonstrated in patients with alkylating agent resistant disease. Recently, larger studies have been organized to study the clinical effects of bendamustine further. In indolent B-cell non-Hodgkin lymphoma that is resistant to rituximab, bendamustine induced a remission in 77% of patients. Myelosuppression was identified as the most common toxicity. In 2 studies of similar populations of patients, the combination of bendamustine and rituximab induced remission 90% of patients with a median progression-free survival of 23-24 months. The overall remission rate was 59% in a prospective, randomized study of untreated patients with chronic lymphocytic leukemia, which was significantly greater than the rate of 26% in the chlorambucil control arm (P < 0.001). Combined with rituximab, bendamustine induces a remission in 67% of patients with relapsed or refractory chronic lymphocytic leukemia. Bendamustine is an active agent for the treatment of low-grade lymphoproliferative disorders and more study is needed to determine which dose and schedule is optimal, and which patients will derive the greatest benefit from its use.

Bendamustine: Rebirth of an Old Drug

Bendamustine is a unique cytotoxic agent with structural similarities to alkylating agents and antimetabolites, but which is non–cross-resistant with alkylating agents and other drugs in vitro and in the clinic. Early clinical studies conducted in the German Democratic Republic more than 30 years ago suggested promising activity in indolent non-Hodgkin's lymphoma (NHL). Two North American trials reported responses in more than 70% of patients with chemotherapy- and rituximab-refractory disease, suggesting that bendamustine may be the most effective drug available for this patient population. Response rates of 90% to 92%, with complete remission in 55% to 60%, have been reported in patients with follicular and mantle-cell lymphoma with the combination of bendamustine and rituximab. Superiority over chlorambucil in previously untreated patients with chronic lymphocytic leukemia (CLL) led to its recent approval for this disease in the United States. Bendamustine is approved in Germany for the treatment of patients with indolent NHL, CLL, and multiple myeloma. Activity has also been noted in patients with breast cancer and small-cell lung cancer. Questions related to the optimization of bendamustine therapy, including dose and schedule, role relative to other available agents, and management of toxicities, are being investigated. However, the availability of bendamustine provides another effective treatment option for patients with lymphoid malignancies.

Role of bendamustine in the treatment of chronic lymphocytic leukemia

Major advances in the management of patients with chronic lymphocytic leukemia (CLL) include an enhanced ability to make an accurate diagnosis and define clinically meaningful prognostic groups, while improving outcome through more effective therapeutic regimens and supportive care. Nevertheless, CLL remains an incurable disorder and new, active agents are needed. Bendamustine, a unique cytotoxic agent with structural similarities to both alkylating agents and antimetabolites, was recently approved by the US Food and Drug Administration for treatment of CLL and rituximab-refractory indolent non-Hodgkin’s lymphoma. In a randomized trial, bendamustine was superior to chlorambucil, with comparable toxicity. Combinations with other active agents including rituximab and lenalidomide are in development. Nevertheless, numerous questions concerning the ideal use of this agent remain to be addressed, including the optimal dose and schedule and mechanisms of resistance. The availability of bendamustine provides another effective treatment option for patients with lymphoproliferative disorders. Rational development of combination regimens will improve the outlook for patients with CLL.

Bendamustine in the treatment of non-Hodgkin's lymphomas

PURPOSE

To review available data using bendamustine alone and in combination with other chemotherapeutic agents in treatment of patients with non-Hodgkin's lymphomas.

METHODS

Internet database searches and literature review.

RESULTS

Bendamustine was approved in March 2008 by the United States Food and Drug Administration for the treatment of patients with chronic lymphocytic leukemia. Many trials have been performed over the last decade using bendamustine not only as monotherapy, but also in combination with other agents including rituximab, vincristine, mitoxantrone, fludarabine, and other agents as therapy for patients with relapsed non-Hodgkin's lymphomas, and recently was approved for use in therapy of patients with relapsed indolent lymphomas considered refractory to rituximab therapy. As monotherapy, bendamustine induces good responses with only minor side effects. In combination with other agents, efficacy improves, especially when given in combination with rituximab. The drug has also been studied in combination with rituximab as initial therapy for indolent lymphomas, and has excellent activity with less toxicity than R-CHOP (rituximab - cyclophosphamide, hydroxydaunorubicin [Adriamycin], Oncovin [vincristine], and prednisone/prednisolone).

CONCLUSION

Overall, bendamustine has demonstrated promising results as therapy for non-Hodgkin's lymphomas and should be included in the armamentarium of agents used to treat relapsed indolent non-Hodgkin's lymphomas and may prove valuable as initial therapy for these diseases. Further studies are being conducted to demonstrate the efficacy of this drug in combination with other agents.

Phase II Multicenter Study of Bendamustine Plus Rituximab in Patients With Relapsed Indolent B-Cell and Mantle Cell Non-Hodgkin's Lymphoma

Purpose

Bendamustine HCl is a bifunctional mechlorethamine derivative with clinical activity in the treatment of non-Hodgkin's lymphoma. This study evaluated bendamustine plus rituximab in 67 adults with relapsed, indolent B-cell or mantle cell lymphoma without documented resistance to prior rituximab.

Patients and Methods

Patients received rituximab 375 mg/m2intravenously on day 1 and bendamustine 90 mg/m2intravenously on days 2 and 3 of each 28-day cycle for four to six cycles. An additional dose of rituximab was administered 1 week before the first cycle and 4 weeks after the last cycle. Sixty-six patients (median age, 60 years) received at least one dose of both drugs.

Results

Overall response rate was 92% (41% complete response, 14% unconfirmed complete response, and 38% partial response). Median duration of response was 21 months (95% CI, 18 to 24 months). Median progression-free survival time was 23 months (95% CI, 20 to 26 months). Outcomes were similar for patients with indolent or mantle cell histologies. The combination was generally well tolerated; the primary toxicity was myelosuppression (grade 3 or 4 neutropenia, 36%; grade 3 or 4 thrombocytopenia, 9%).

Conclusion

Bendamustine plus rituximab is an active combination in patients with relapsed indolent and mantle cell lymphoma.

Bendamustine as a model for the activity of alkylating agents

Attempts to administer personalized standard cytotoxic chemotherapy based on individual patient characteristics have been disappointing. Alkylating agents are one of the oldest classes of anticancer medicine with a wide variety of molecular actions and thus the potential for broad utility. Bendamustine hydrochloride, a new addition to this class, was previously developed in the 1960s and has now been trialled in hematological malignancies and many solid tumor types as monotherapy or in combination with the known standard of care. It appears to occupy a particular role in resistant or refractory hematological disease and it was approved by the US FDA for the treatment of chronic lymphocytic leukemia in March 2008. Further trials will reveal whether it is likely to become incorporated into front-line regimens in non-Hodgkin's lymphoma and other malignancies.

Bendamustine; Levoleucovorin

The complexity of cancer chemotherapy requires that pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy and the agents, both commercially available and investigational, used to treat malignant diseases.

High anti-lymphoma activity of bendamustine/mitoxantrone/rituximab in rituximab pretreated relapsed or refractory indolent lymphomas and mantle cell lymphomas. A multicenter phase II study of the German Low Grade Lymphoma Study Group (GLSG)

On the basis of a preceding phase I study, the current trial explored bendamustine in combination with mitoxantrone and rituximab (BMR) in patients with stage III/IV relapsed or refractory indolent lymphomas and mantle cell lymphoma (MCL) with or without prior rituximab containing chemo-immunotherapy (R-chemo) treatment. Therapy consisted of bendamustine 90 mg/m(2) days 1 + 2, mitoxantrone 10 mg/m(2) day 1, rituximab 375 mg/m(2) day 8. Treatment was repeated on day 29 for a total of four cycles. Between 3 April and 04 July, 57 patients were recruited from 24 participating institutions, 39% of whom had received prior R-chemo therapy. Median age was 66 years (40 - 83). Lymphoma subtypes were 29 follicular (FL), 18 MCL, and 10 other indolent lymphomas. The overall response rate (ORR) was 89% with 35% CR and 54% PR. ORR in R-chemo pretreated patients was 76% (38% CR, 38% PR). After a median observation time of 27 months (1 - 43), the estimated median progression free survival is 19 months. The 2 year overall survival is 60% for patients with FL and MCL. Treatment related toxicities of grade 3/4 comprised a reversible myelosuppression (10% anemia, 78% leukocytopenia, 46% granulocytopenia, 16% thrombocytopenia). However, unexpected hospitalisations were necessary after 4% of BMR-application only. BMR is a very effective new outpatient immuno-chemotherapy with low toxicity for patients with relapsed/refractory FL, MCL and other indolent lymphomas.

How I treat refractory CLL

Therapy for patients with chronic lymphocytic leukemia (CLL) has greatly changed over the past few years. After years of stagnation, with treatment revolving around the use of rather ineffective drugs such as alkylators, many patients are now being treated with more effective agents such as purine analogs either alone or combined with other drugs and/or monoclonal antibodies. Treatment of patients refractory to these treatments is particularly challenging and should be decided only upon a careful evaluation of the disease, patient characteristics, and prognostic factors. Refractory disease should be clearly separated from relapsing disease. The only curative therapy for patients with CLL, including those with refractory disease, is allogeneic stem cell transplantation. However, the use of allogeneic transplantation is limited because of the advanced age of most patients and the high transplant-related mortality (TRM). Transplants with nonmyeloablative regimens may reduce TRM and allow more patients to receive transplants more safely. For patients in whom an allogeneic transplantation is not feasible or in whom it is deemed inappropriate, participation in phase 2 trials should be encouraged. Finally, to investigate mechanisms to overcome resistance to therapy in CLL and to identify patients that might gain benefit from early, intensive therapies (eg, based on biologic markers) constitute a challenge that needs active investigation.

Bendamustine, vincristine and prednisone (BOP) versus cyclophosphamide, vincristine and prednisone (COP) in advanced indolent non-Hodgkin's lymphoma and mantle cell lymphoma: results of a randomised phase III trial (OSHO# 19)

PURPOSE

The purpose of this study was to compare the efficacy and toxicity of bendamustine, vincristine + prednisone (BOP) with a standard regimen of cyclophosphamide, vincristine + prednisone (COP) in patients with previously untreated advanced indolent non-Hodgkin's lymphoma (NHL) and mantle cell lymphoma.

METHODS

A total of 164 patients with follicular lymphoma (grade 1/2), mantle cell lymphoma or lymphoplasmacytic lymphoma (immunocytoma) was randomised to treatment with vincristine 2 mg (day 1) and prednisone 100 mg/m2 (days 1-5) + bendamustine 60 mg/m2 (days 1-5) or + cyclophosphamide 400 mg/m2 (days 1-5) for a total of eight 21-day cycles.

RESULTS

The rate of complete remission was 22% with BOP and 20% with COP. The projected 5-year survival rate was 61% with BOP and 46% with COP. The BOP-associated 5-year survival advantage almost reached significance in the subgroup of patients who responded to therapy (74% vs. 56%; P = 0.05), and did reach significance in responders who did not receive interferon maintenance therapy (70% vs. 47%; P = 0.03). Toxicity was acceptable in both treatment groups, although alopecia and leucopenia were more severe with COP.

CONCLUSIONS

Bendamustine can efficaciously and safely replace cyclophosphamide, as used in standard COP therapy, for the treatment of patients with indolent NHL and mantle cell lymphoma. Long-term survival data suggest a clinically significant benefit for patients treated with BOP.