Regression of brain metastases from breast carcinoma after chemotherapy with bendamustine

A case of neurolymphomatosis caused by follicular lymphoma successfully treated with bendamustine

Currently, there is no standard treatment for neurolymphomatosis because of the scarcity of clinical studies. Here, we report the successful treatment of neurolymphomatosis caused by follicular lymphoma with bendamustine, which could be an effective treatment option for this condition.

Chemotherapy and biological treatment options in breast cancer patients with brain metastasis: an update

INTRODUCTION

Breast cancer (BC) is the second most common cause of CNS metastasis. Ten to 20% of all, and 38% of human epidermal growth factor-2(+), metastatic BC patients experience brain metastasis (BM). Prolonged survival with better control of systemic disease and limited penetration of drugs to CNS increased the probability of CNS metastasis as a sanctuary site of relapse. Treatment of CNS disease has become an important component of overall disease control and quality of life.

AREAS COVERED

Current standard therapy for BM is whole-brain radiotherapy, surgery, stereotactic body radiation therapy for selected cases, corticosteroids and systemic chemotherapy. Little progress has been made in chemotherapy for the treatment of BM in patients with BC. Nevertheless, new treatment choices have emerged. In this review, we aimed to update current and future treatment options in systemic treatment for BM of BC.

EXPERT OPINION

Cornerstone local treatment options for BM of BC are radiotherapy and surgery in selected cases. Efficacy of cytotoxic chemotherapeutics is limited. Among targeted therapies, lapatinib has activity in systemic treatment of BM particularly when used in combination with capecitabine. Novel agents are currently investigated.

Phase I study of bendamustine with concurrent whole brain radiation therapy in patients with brain metastases from solid tumors

A phase I study was conducted to evaluate the dose-limiting toxicities (DLTs) and to determine the maximum tolerated dose (MTD)/recommended phase II dose of bendamustine with concurrent whole brain radiation (WBR) in patients with brain metastases (BM) from solid tumors. Four doses of intravenous weekly bendamustine were administered with 3 weeks of WBR at three dose levels (60, 80, and 100 mg/m(2)) according to a standard 3 + 3 phase I design. A total of 12 patients with solid tumor BM were enrolled in the study (six with non-small cell lung cancer, four with melanoma, one with breast cancer, and one with neuroendocrine carcinoma). The first two dose levels had three patients each, and the third dose level had six total patients. Plasma pharmacokinetic studies of bendamustine demonstrated no significant differences from pharmacokinetic characteristics of bendamustine in other studies. No DLTs were noted at any dose levels, and no grade 4 toxicities occurred. The MTD of weekly bendamustine with concurrent WBR was 100 mg/m(2). The majority of trial patients died from progressive systemic disease rather than their brain disease. The combination of weekly bendamustine with concurrent WBR was acceptably tolerated. The efficacy of this combination may be evaluated in a phase II trial with stratification by histologies.

Severe and prolonged lymphopenia observed in patients treated with bendamustine and erlotinib for metastatic triple negative breast cancer

PURPOSE

Triple negative breast cancers (TNBC) frequently have high epidermal growth factor receptor (EGFR) expression and are sensitive to DNA-damaging agents. Improved therapies are needed for this aggressive malignancy.

PATIENTS AND METHODS

We performed a phase I trial of bendamustine and erlotinib, an EGFR tyrosine kinase inhibitor, in patients with metastatic TNBC, ECOG performance status ≤2, and ≤1 prior chemotherapy for metastatic disease. Each 28-day cycle included intravenous bendamustine on days 1, 2 and oral erlotinib on days 5-21 with dose escalation according to a 3 + 3 phase I study design. Dose-limiting toxicity (DLT) was determined by toxicities related to study therapy observed during cycle 1.

RESULTS

Eleven patients were treated, 5 on dose level 1 and 6 on dose level 2. One patient had DLT on dose level 2. However, cumulative toxicities were observed, including grade 3/4 lymphopenia in 91 % (95 % CI 0.59-0.998) with progressively decreased CD4 counts and grade ≥3 infections in 36 % (95 % CI 0.11-0.69) of patients.

CONCLUSIONS

Combination therapy with bendamustine and erlotinib causes excessive toxicity with severe, prolonged lymphopenia, depressed CD4 counts, and opportunistic infections and should not be pursued further. Future trials of bendamustine combinations in TNBC patients should account for potential cumulative lymphocyte toxicity necessitating patient monitoring during and after treatment.

Salvage therapy with single agent bendamustine for recurrent glioblastoma

The treatment of recurrent glioblastoma (GBM) remains challenging notwithstanding the recent approval of bevacizumab for this indication. Bendamustine has a bifunctional mechanism of action including alkylation, penetrates the CNS and does not show cross resistance to other alkylator chemotherapies. In a single institution phase 2 trial, patients with recurrent GBM were treated with bendamustine (100 mg/m(2)/day administered intravenously for two consecutive days every 4 weeks). The primary study endpoint was 6-month progression free survival (PFS-6). An interim analysis for futility was conducted according to a Simon two-stage minimax design. Complete blood counts were obtained bimonthly, clinical evaluations and brain imaging every month for the first cycle and bimonthly thereafter. Treatment responses were based upon MacDonald criteria. Sixteen patients were enrolled (nine men; seven women), with a median age of 53 years (range 36-68) and a median Karnofsky performance status of 90 (range 70-100). Nine patients were treated at first relapse and seven at second relapse (five patients were bevacizumab failures). A total of 25 cycles of bendamustine were administered with a median of 1 (range 1-6). Bendamustine-related toxicity was seen in eight patients; lymphopenia in seven (5 grade 3; 2 Grade 4), thrombocytopenia in two (1 Grade 3; 1 Grade 4), and neutropenia in one (1 Grade 3). Fourteen patients have died due to disease progression, two patients are alive and on alternative therapies. Only one patient was progression-free at 6 months, triggering the stopping rule for futility. Bendamustine was reasonably well tolerated but failed to meet the study criteria for activity in adults with recurrent GBM.

Systemic treatment in breast-cancer patients with brain metastasis

IMPORTANCE OF THE FIELD

Breast cancer is the second most common cause of CNS metastasis, following lung cancer. With better control of systemic disease, the CNS is emerging as a sanctuary site of relapse in patients with otherwise controlled cancer.

AREAS COVERED IN THIS REVIEW

Standard therapy for brain metastasis is currently whole-brain radiotherapy. Other treatment modalities include surgery and radiosurgery in selected cases, corticosteroids, and systemic chemotherapy. Little progress has been made in chemotherapy for the treatment of brain metastases, partly because tumors develop brain metastases at a stage when they become totally chemoresistant. Nevertheless, new treatment choices have emerged considering cytotoxic and biological agents for the treatment of CNS metastases in patients with breast cancer.

WHAT THE READERS WILL GAIN

In this review, we aimed to review current and future treatment options in the systemic treatment of brain metastases of breast cancer.

TAKE HOME MESSAGE

Corticosteroids, anti-epileptic drugs, and radiotherapy remain the cornerstones of management. The efficacy of conventional cytotoxic chemotherapeutics is limited. Novel biologic agents, lapatinib being the most promising, are currently investigated in the treatment of brain metastases of breast cancer with promising results.

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.

Bendamustine in Metastatic Breast Cancer: An Old Drug in New Design

The goal of treatment for patients with advanced breast cancer is to prolong survival, control symptoms, and reduce disease-related complications. Despite the introduction of many cytotoxic agents during the past decade, only modest improvement in survival in metastatic breast cancer has been achieved. In order to improve this situation, new cytotoxic drugs as well as molecule-targeted agents are now under investigation. Bendamustine is a bifunctional alkylating agent with cytotoxic activity against several types of solid tumors. In the search for new anthracycline-free combinations, taxanes and alkylating agents might be worth investigating, in order to reduce cardiac toxicity. In this article, we reviewed the latest information regarding antitumor activity, toxicity, pharmacokinetics, and clinical application of bendamustine as a cytotoxic agent in metastatic breast cancer.

Central nervous system metastases in HER-2-overexpressing metastatic breast cancer: a treatment challenge

With improvements in diagnostic and therapeutic options and a corresponding improvement in survival, central nervous system (CNS) metastasis is becoming a more frequent diagnosis in breast cancer patients. It can be assumed that up to 30% of metastatic breast cancer (MBC) patients may experience CNS metastasis during the course of their disease. Moreover, it has been reported that patients with human epidermal growth factor receptor (HER)-2-overexpressing MBC are at a higher risk for CNS involvement. Whereas locoregional treatment modalities such as surgery, radiosurgery, and whole-brain radiotherapy still must be considered as the treatment of first choice, the armamentarium of systemic treatment modalities has been expanded by the introduction of small molecules such as the tyrosine kinase inhibitors. Rather than analyzing the risk factors for the development of CNS metastasis and reviewing the standard diagnostic and therapeutic approaches in patients with CNS involvement, this review focuses specifically on systemic treatment modalities in patients suffering from CNS metastasis from HER-2-overexpressing MBC.

Multidisciplinary management of brain metastases

Metastatic brain tumors are the most common intracranial neoplasms in adults. The incidence of brain metastases appears to be rising as a result of superior imaging modalities, earlier detection, and more effective treatment of systemic disease. Therapeutic approaches to brain metastases include surgery, whole brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), and chemotherapy. Treatment decisions must take into account clinical prognostic factors in order to maximize survival and neurologic function whilst avoiding unnecessary treatments. The goal of this article is to review important prognostic factors that may guide treatment selection, discuss the roles of surgery, radiation, and chemotherapy in the treatment of patients with brain metastases, and present new directions in brain metastasis therapy under active investigation. In the future, patients will benefit from a multidisciplinary approach focused on the integration of surgical, radiation, and chemotherapeutic options with the goal of prolonging survival, preserving neurologic and neurocognitive function, and maximizing quality of life.

Bendamustine induces G2 cell cycle arrest and apoptosis in myeloma cells: the role of ATM-Chk2-Cdc25A and ATM-p53-p21-pathways

PURPOSE

Multiple myeloma is a fatal hematological disease caused by malignant transformation of plasma cells. Bendamustine has been proven to be a potent alternative to melphalan in phase 3 studies, yet its molecular mode of action is still poorly understood.

METHODS

The four-myeloma cell lines NCI-H929, OPM-2, RPMI-8226, and U266 were cultured in vitro. Apoptosis was measured by flow cytometry after annexin V FITC and propidium iodide staining. Cell cycle distribution of cells was determined by DNA staining with propidium iodide. Intracellular levels of (phosphorylated) proteins were determined by western blot.

RESULTS

We show that bendamustine induces apoptosis with an IC50 of 35-65 mug/ml and with cleavage of caspase 3. Incubation with 10-30 mug/ml results in G2 cell cycle arrest in all four-cell lines. The primary DNA-damage signaling kinases ATM and Chk2, but not ATR and Chk1, are activated. The Chk2 substrate Cdc25A phosphatase is degraded and Cdc2 is inhibited by inhibitory phosphorylation of Tyr15 accompanied by increased cyclin B levels. Additionally, p53 activation occurs as phosphorylation of Ser15, the phosphorylation site for ATM. p53 promotes Cdc2 inhibition by upregulation of p21. Targeting of p38 MAPK by the selective inhibitor SB202190 significantly increases bendamustine induced apoptosis. Additionally, SB202190 completely abrogates G2 cell cycle arrest.

CONCLUSION

Bendamustine induces ATM-Chk2-Cdc2-mediated G2 arrest and p53 mediated apoptosis. Inhibition of p38 MAPK augments apoptosis and abrogates G2 arrest and can be considered as a new therapeutic strategy in combination with bendamustine.

A phase I study of bendamustine hydrochloride administered once every 3 weeks in patients with solid tumors

The present phase I trial was planned to assess the maximum tolerated dose, the dose-limiting toxicity and the pharmacokinetics of bendamustine hydrochloride in a once every 3 weeks schedule, and to recommend a safe dose for future phase II studies. Included were patients with refractory solid tumors. Bendamustine hydrochloride was administered as a short intravenous infusion over 30 min. The starting dose was defined at 160 mg/m2 and dose escalation used increments of 20 mg/m2. Plasma and urine samples were analyzed using validated high-pressure liquid chromatography/fluorescence assays. Twenty-six patients (14 men, 12 women) were enrolled for the study. At 280 mg/m2, one out of four patients developed a thrombocytopenia grade 4, two experienced grade 3 fatigue and three experienced cardiac toxicity (grade 2). The latter toxicity was considered dose limiting also and further dose escalation was stopped. Plasma pharmacokinetics parameters of bendamustine hydrochloride and its metabolites were assessed in 15 patients. Mean pharmacokinetic parameters of bendamustine hydrochloride were a tmax of 32.3 min, a t1/2 of 37.8 min, a volume of distribution of 14.2 l/m and a clearance of 287.8 ml/min/m2. No dose dependency of bendamustine hydrochloride was observed within the used dose range. The metabolites comprised only 23% of the overall area under the concentration-time curve. The maximum tolerated dose of bendamustine hydrochloride on day 1 q 3 weeks is 280 mg/m2. Fatigue and cardiac toxicity were dose limiting. The plasma pharmacokinetics data of bendamustine and its metabolites were in accordance with previous reports. The recommended dose for future trials is 260 mg/m2 every 3 weeks.

A phase I study of bendamustine hydrochloride administered day 1+2 every 3 weeks in patients with solid tumours

The aim of the study was to determine the maximum tolerated dose (MTD), the dose limiting toxicity (DLT), and the pharmacokinetic profile (Pk) of bendamustine (BM) on a day 1 and 2 every 3 weeks schedule and to recommend a safe phase II dose for further testing. Patients with solid tumours beyond standard therapy were eligible. A 30-min intravenous infusion of BM was administered d1+d2 q 3 weeks. The starting dose was 120 mg m(-2) per day and dose increments of 20 mg m(-2) were used. Plasma and urine samples were analysed using validated high-performance liquid chromatography/fluorescence assays. Fifteen patients were enrolled. They received a median of two cycles (range 1-8). The MTD was reached at the fourth dose level. Thrombocytopaenia (grade 4) was dose limiting in two of three patients at 180 mg m(-2). One patient also experienced febrile neutropaenia. Lymphocytopaenia (grade 4) was present in every patient. Nonhaematologic toxicity including cardiac toxicity was not dose limiting with this schedule. Mean plasma Pk values of BM were tmax 35 min, t(1/2) 49.1 min, Vd 18.3 l m(-2), and clearance 265 ml min(-1) m(-2). The mean total amount of BM and its metabolites recovered in the first micturition was 8.3% (range 2.7-26%). The MTD of BM in the present dose schedule was 180 mg m(-2) on day 1+2. Thrombocytopaenia was dose limiting. The recommended dose for future phase II trials with this schedule is 160 mg m(-2) per day.

Phase II Trial with Carboplatin and Bendamustine in Patients with Extensive Stage Small-Cell Lung Cancer

BACKGROUND

Bendamustine is an alkylating agent with hybrid activity and proven efficacy in small-cell lung cancer associated with a favorable toxicity rate. This phase II study of carboplatin/bendamustine was conducted to evaluate the efficacy of this combination in patients with extensive disease small-cell lung cancer (ED-SCLC).

METHODS

Fifty-six untreated patients with ED-SCLC were enrolled. Their median age was 63 years. Sixty-seven percent of patients were male and 18% had a World Health Organization performance status of 2. Bendamustine was administered as a 30- to 60-minute infusion at a dose of 80 mg/m2 on days 1 and 2, and carboplatin was given at an area under the curve of 5 on day 1 of a 21-day cycle.

RESULTS

Fifty-five patients were assessable for response and toxicity. The overall response rate was 72.7% (95% confidence interval: 59%-84%), with one complete remission (1.8%). The median time to progression was 5.2 months (95% confidence interval: 4.2-5.6). At the time of evaluation, 71% of the patients had died. The median survival time reached 8.3 months (95% confidence interval: 6.6-9.9). The major toxicity of this regimen was myelosuppression, including grade 3 or 4 neutropenia (46%), thrombopenia (26%), anemia (15%), and infections (11%). Toxic death was recorded in two patients (3.6%).

CONCLUSIONS

The carboplatin/bendamustine regimen is a well-tolerated cytostatic combination in ED-SCLC with activity comparable with that of other platinum-based regimens. Further investigations, such as a phase III trial, are currently planned.

Chemotherapy and targeted molecular therapies for brain metastases

As therapy for systemic cancers improves, an increasing number of patients are developing brain metastases. Although conventional therapy with surgery, radiation therapy and radiosurgery has improved the outcome of a significant number of patients, many develop multiple lesions that are not amenable to standard treatments. In this review, the current role of chemotherapy and targeted molecular agents for brain metastases is summarized and future directions are discussed.

Characterization of two phase I metabolites of bendamustine in human liver microsomes and in cancer patients treated with bendamustine hydrochloride

PURPOSE

The metabolism of bendamustine (BM) hydrochloride, a bifunctional alkylator containing a heterocyclic ring, was investigated in vitro and in vivo for identification of cytochromes P450 (CYP) involved in the formation of two phase I metabolites, structural confirmation of these previously unidentified metabolites and assessment of their cytotoxic effect in relation to the parent compound.

METHODS

Potential metabolites of BM were synthesized and structurally characterized by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC-MS) analysis. In vitro metabolism of BM hydrochloride in human hepatic microsomes was conducted to identify the CYP450 isoenzymes involved in the oxidative metabolism of BM. Samples from cancer patients after treatment with BM hydrochloride and microsomal preparations were analyzed by LC-MS and HPLC with fluorescence detection. The cytotoxic effect of the metabolites was analyzed in several lymphoma cell lines and peripheral blood lymphocytes and compared with that of the parent compound using an MTT assay.

RESULTS

LC-MS as well as HPLC with fluorescence detection revealed hydroxylation of the methylene carbon at the C-4 position of the butanoic acid side chain and N-demethylation of the benzimidazole skeleton as the main metabolic pathways in human liver microsomes. Isoform-specific chemical inhibitors and correlation analysis pointed to CYP1A2 as the prominent enzyme in BM oxidation. The rate of formation for both metabolites correlated (r=0.931 and 0.933) with the activity of CYP1A2 and there were no other notable correlations with any of the other CYPs. In addition, both metabolites were identified in plasma, urine, and bile samples from cancer patients under BM hydrochloride therapy as shown by comparison with chromatograms obtained from the authentic reference standards. Cytotoxic activity observed for gamma-hydroxy BM was approximately equivalent to that obtained for the parental compound BM. N-demethyl BM displays five to tenfold less cytotoxic activity than BM.

CONCLUSION

The results indicate that CYP1A2-catalyzed N-dealkylation and gamma hydroxylation are the major routes for BM phase I metabolism producing two metabolites less or similarly toxic than the parent compound. In contrast to the metabolic pathways of the structurally related chlorambucil, no beta-oxidation of the butanoic acid side chain leading to enhanced toxicity was detected for BM.

CNS Metastases in Breast Cancer

As systemic therapy of metastatic breast cancer improves, CNS involvement is becoming a more widespread problem. This article summarizes the current knowledge regarding the incidence, clinical presentation, diagnosis, prognosis, and treatment of CNS metastases in patients with breast cancer. When available, studies specific to breast cancer are presented; in studies in which many solid tumors were evaluated together, the proportion of patients with breast cancer is noted. On the basis of data from randomized trials and retrospective series, neurosurgery and stereotactic radiosurgery (SRS) may prolong survival in patients with single brain metastases. The treatment of multiple metastases remains controversial, as does the routine use of whole-brain radiotherapy (WBRT) after either surgery or SRS. Although it is widely assumed that chemotherapy is of limited benefit, data from case series and case reports suggest otherwise. WBRT, neurosurgery, SRS, and medical therapy each have a role in the treatment of CNS metastases; however, neurologic symptoms frequently are not fully reversible, even with appropriate therapy. Studies specifically targeted toward this group of patients are needed.