Feasibility and pharmacokinetic study of bendamustine hydrochloride in combination with rituximab in relapsed or refractory aggressive B cell non-Hodgkin’s lymphoma6

A phase I/II study of 10-min dosing of bendamustine hydrochloride (rapid infusion formulation) in patients with previously untreated indolent B-cell non-Hodgkin lymphoma, mantle cell lymphoma, or relapsed/refractory diffuse large B-cell lymphoma in Japan

Purpose

This phase I/II clinical study was conducted to examine the safety, tolerability, pharmacokinetics, and efficacy of 10-min dosing of bendamustine in patients with previously untreated indolent B-cell non-Hodgkin lymphoma (iNHL) or mantle cell lymphoma (MCL) (Group 1) and patients with relapsed/refractory diffuse large B-cell lymphoma (rrDLBCL) (Group 2).

Methods

Rituximab 375 mg/m² was administered intravenously every 28 days to Group 1 patients on day 1 and every 21 days to Group 2 patients on day 1. Bendamustine 90 mg/m²/day was administered to the former on days 1 and 2; bendamustine 120 mg/m²/day was administered to the latter on days 2 and 3. Each regimen was delivered up to six cycles for both groups. The primary endpoints were safety and tolerability in Groups 1 and 2, respectively.

Results

Among 37 enrolled patients, safety was assessed in 36. In Group 1 (n = 30), 27 patients (90%) had follicular lymphoma. Adverse events (AEs) were observed in all 30 patients in Group 1. Dose-limiting toxicities were observed in two of six patients in Group 2. Common AEs included lymphocyte count decreased (86.7%, 100%). In Group 1, overall response and complete response rates were 93.1% (95% confidence interval [CI] 77.2–99.2%) and 75.9% (95% CI 56.5–89.7%), respectively. The C_max and AUC of bendamustine tended to be higher in Group 2 than in Group 1.

Conclusions

This study showed that bendamustine is safe, well-tolerated and effective for patients with previously untreated iNHL, MCL or rrDLBCL. Pharmacokinetic data were equivalent to those obtained outside of Japan.

Registration numbers

Registration NCT03900377; registered April 3, 2019.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00280-022-04442-2.

Bendamustine treatment of Chinese patients with relapsed indolent non-Hodgkin lymphoma: a multicenter, open-label, single-arm, phase 3 study

BACKGROUND

Bendamustine was approved in China on May 26th, 2019 by the National Medical Product Administration for the treatment of indolent B-cell non-Hodgkin lymphoma (NHL). The current study was the registration trial and the first reported evaluation of the efficacy, safety, and pharmacokinetics of bendamustine in Chinese adult patients with indolent B-cell NHL following relapse after chemotherapy and rituximab treatment.

METHODS

This was a prospective, multicenter, open-label, single-arm, phase 3 study (NCT01596621; C18083/3076) with a 2-year follow-up period. Eligible patients received bendamustine hydrochloride 120 mg/m2 infused intravenously on days 1 and 2 of each 21-day treatment cycle for at least six planned cycles (and up to eight cycles). The primary endpoint was the overall response rate (ORR); and secondary endpoints were duration of response (DoR), progression-free survival (PFS), safety, and pharmacokinetics. Patients were classified according to their best overall response after initiation of therapy. Proportions of patients in each response category (complete response [CR], partial response [PR], stable disease, or progressive disease) were summarized along with a two-sided binomial exact 95% confidence intervals (CIs) for the ORR.

RESULTS

A total of 102 patients were enrolled from 20 centers between August 6th, 2012, and June 18th, 2015. At the time of the primary analysis, the ORR was 73% (95% CI: 63%-81%) per Independent Review Committee (IRC) including 19% CR and 54% PR. With the follow-up period, the median DoR was 16.2 months by IRC and 13.4 months by investigator assessment; the median PFS was 18.6 months and 15.3 months, respectively. The most common non-hematologic adverse events (AEs) were gastrointestinal toxicity, pyrexia, and rash. Grade 3/4 neutropenia was reported in 76% of patients. Serious AEs were reported in 29 patients and five patients died during the study. Pharmacokinetic analysis indicated that the characteristics of bendamustine and its metabolites M3 and M4 were generally consistent with those reported for other ethnicities.

CONCLUSION

Bendamustine is an active and effective therapy in Chinese patients with relapsed, indolent B-cell NHL, with a comparable risk/benefit relationship to that reported in North American patients.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, No. NCT01596621; https://clinicaltrials.gov/ct2/show/NCT01596621.

Combined rituximab, bendamustine, and dexamethasone chemotherapy for relapsed or refractory indolent B-cell non-Hodgkin lymphoma and mantle cell lymphoma: a multicenter phase II study

This multicenter phase II study (UMIN000008145) aims to investigate the efficacy and safety of six cycles of combination therapy (RBD) comprising rituximab, bendamustine, and dexamethasone (DEX) for relapsed or refractory (RR) indolent B-cell non-Hodgkin lymphoma (B-NHL) and mantle cell lymphoma (MCL). Although the initial study protocol comprised 20 mg/body DEX on days 1 and 2, and 10 mg/body on days 3-5 [high-dose (HD-) DEX group], the dose of DEX was later decreased to 8 mg/body on days 1 and 2 [low-dose (LD-) DEX group] due to frequent cytomegalovirus (CMV) antigenemia and recurrent retinitis. We enrolled 33 patients, and LD-DEX and HD-DEX were administered in 15 and 18 patients, respectively. The overall response and the 3-year progression-free survival rates were 88% and 75.5%, respectively. The leading adverse event was myelosuppression. Incidence of grade 3-4 leukocytopenia, neutropenia, and lymphocytopenia was 55%, 67%, and 91%, respectively. The most frequent nonhematological adverse events were CMV antigenemia and rash (33% and 30%, respectively). Incidence of CMV antigenemia over 10/100,000 white blood cells was significantly lower with LD-DEX than that with HD-DEX (P = 0.0127). In conclusion, RBD showed significant effectiveness for RR indolent B-NHL and MCL.

High-dose Bendamustine-EAM followed by autologous stem cell rescue results in long-term remission rates in lymphoma patients, without renal toxicity

BACKGROUND

Autologous stem cell transplantation (ASCT) following BEAM (BCNU, etoposide, cytarabine, melphalan) conditioning is standard of care in relapsed low- and high-grade B-cell lymphoma (DLBCL) and other lymphoproliferative disorders, but BCNU is associated with interstitial pneumonia and an increased mortality. A less toxic regimen might improve the outcome of patients with lymphoma after transplantation.

OBJECTIVES

We investigated the role of bendamustine replacing BCNU in the BEAM regimen in patients with lymphoma undergoing ASCT.

PATIENTS/METHODS

The conditioning regimen BendaEAM consisted of bendamustine, cytarabine, etoposide, and melphalan and was used in patients with Hodgkin's disease (HD) and Non-Hodgkin lymphoma (NHL).

RESULTS

Forty-one patients with HD (n = 9) or NHL (n = 32) were consecutively treated with Benda-BEAM replacing BCNU. No pulmonary or renal toxicities occurred, and no patient died related to transplant. After a median follow-up of 55 months, CR rate was 56%, 18 patients (44%) showed progression after a median time of 7 months after transplantation (range: 2-29 months), and 11 patients (24%) have died, all due to lymphoma progression. The 1-, 2-, and 4-year PFS are 73.2%, 58.6%, and 55.6% and the 1-, 2-, and 4-year OS 85.4%, 78.0%, and 72.6%, respectively.

CONCLUSION

BendaEAM seems to be feasible with a promising response rate and acceptable toxicity.

Rituximab plus bendamustine as front-line treatment in frail elderly (>70 years) patients with diffuse large B-cell non-Hodgkin lymphoma: a phase II multicenter study of the Fondazione Italiana Linfomi

We conducted a phase II study to assess activity and safety profile of bendamustine and rituximab in elderly patients with untreated diffuse large B-cell lymphoma (DLBCL) who were prospectively defined as frail using a simplified version of the Comprehensive Geriatric Assessment (CGA). Patients had to be over 70 years of age, with histologically confirmed DLBCL. Frail patients were those younger than 80 years with a frail profile at CGA or older than 80 years with an unfit profile. Treatment consisted of 4-6 courses of bendamustine [90 mg/m² days (d)1-2] and rituximab (375 mg/m² d1) administered every 28 days. Other main study end points were complete remission rate and the rate of extra-hematologic adverse events. Forty-nine patients were enrolled of whom 45 were confirmed eligible. Overall, 24 patients achieved a complete remission (53%; 95%CI: 38-68%) and the overall response rate was 62% (95%CI: 47-76%). The most frequent grade 3-4 adverse event was neutropenia (37.8%). Grade 3-4 extra-hematologic adverse events were observed in 7 patients (15.6%; 95%CI: 6.5-29.5%); the most frequent was grade 3 infection in 2 patients. With a median follow up of 33 months (range 1-52), the median progression-free survival was ten months (95%CI: 7-25). The study shows promising activity and manageable toxicity profile of BR combination as first-line therapy for patients with DLBCL who are prospectively defined as frail according to a simplified CGA, as adopted in this trial (clinicaltrials.gov identifier: 01990144).

Bendamustine hydrochloride in patients with B-cell malignancies who have comorbidities - is there an optimal dose?

INTRODUCTION

The majority of patients with non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL) present with comorbidities. Many of them are poor candidates for intensive chemo-immunotherapy regimens, such as FCR (fludarabine, cyclophosphamide, rituximab). Still, most clinical trials aim to enroll 'fit' patients, who poorly represent the community oncology population. Areas covered: In the past decade, bendamustine hydrochloride, a cytotoxic agent with structural similarities to both alkylating agents and purine analogs, has received widespread use in therapy of NHL and CLL, and has demonstrated a relatively favorable toxicity profile. However, bendamustine has not been well studied in patients with hematologic malignancies who have comorbidities. Here we review the clinical data on use of bendamustine in older and unfit patients with NHL and CLL, and analyze whether there is an optimal dose of bendamustine in patients who have significant comorbidities, including renal dysfunction. Expert commentary: Reduced intensity regimens of bendamustine are effective in CLL patients with comorbidities and renal dysfunction. Even with the introduction of targeted therapies, bendamustine will likely continue to be an important therapeutic option in patients with comorbidities because of its tolerability, efficacy and cost.

Extended Follow-up of Patients Treated With Bendamustine for Lymphoid Malignancies

INTRODUCTION

Bendamustine, typically in combination with rituximab, is an effective treatment for chronic lymphocytic leukemia (CLL) and B-cell non-Hodgkin lymphoma. Despite its acceptable short-term toxicity profile, long-term toxicities are less well established. This study investigated the long-term adverse effects of bendamustine and responses to subsequent treatments.

PATIENTS AND METHODS

Charts of 194 patients were retrospectively reviewed; 54% had received prior treatment (76% attained complete response [CR] or partial response [PR]).

RESULTS

Patients who did not achieve a CR or PR did not respond well to subsequent treatments. Malignancies following bendamustine were diagnosed in 11% (21) of patients (first line [7] and salvage [14]), including squamous (8) or basal cell (4) skin cancers; prostate cancer (3), renal cancer (3), bladder cancer (2), melanoma (2), lung cancer (1), and histiocytic sarcoma (1). There were no occurrences of therapy-related myelodysplastic syndrome or acute myelogenous leukemia reported. Infections occurred in 63% of patients; however, no deaths were attributable to bendamustine.

CONCLUSION

Bendamustine is an effective therapy with limited long-term sequelae in patients with lymphoid malignancies.

Diffuse Large B-cell Lymphoma in the elderly: standard treatment and new perspectives

INTRODUCTION

Diffuse large B-cell lymphoma (DLBCL) is the most common histotype in non Hodgkin lymphoma, with a peak incidence in the sixth decade. The standard treatment for elderly FIT DLBCL patients is Rituximab-CHOP; in unfit and frail patients, chemotherapy at reduced intensity should be considered. Areas covered: In this article, we will review use of standard therapies and new drugs investigated such as immonomudulating agents (IMiDs), Bruton Tyrosine Kinase (BTK), in fit, unfit, frail and very elderly DLCBL patients. Expert commentary: R-CHOP21 in fit DLBCL patients is still the standard of care, while in elderly unfit patients a reduction of doses of cytotoxic drugs or schemes that avoid antracycline should be considered. The Comprensive Geriatric Assesment based in age, comorbidities and functional abilities of daily living is an important tool in elderly, in order to discriminate between fit, unfit or frail patients. Novel drugs represent valid therapeutic options in relapsed/refractory setting so continued participation in clinical trials should be encouraged.

A phase II trial of bendamustine in combination with rituximab in older patients with previously untreated diffuse large B-cell lymphoma

Bendamustine in combination with rituximab (BR) has been associated with high response rates and acceptable toxicity in older patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL). Evaluation of BR is warranted in the front-line setting for DLBCL patients not eligible for anthracyclines or for the elderly. In this phase II study, we enrolled DLBCL patients aged ≥65 years who were poor candidates for R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) to determine the efficacy and safety of BR in previously untreated stage II-IV DLBCL. Twenty-three patients were enrolled with a median age of 80 years. 52% of patients presented with poor functional status (Eastern Cooperative Oncology Group performance score of ≥2). The overall response rate was 78% with 12 complete responses (52%). At a median follow up of 29 months, the median overall survival was 10·2 months and the median progression-free survival was 5·4 months. The most common grade 3/4 adverse events were haematological. Combination therapy with BR demonstrates high response rates as front-line therapy in frail older patients with DLBCL, but survival rates were low. BR should be used with caution in future clinical trials involving older DLBCL patients with poor functional status.

Safety and efficacy of rituximab plus bendamustine in relapsed or refractory diffuse large B-cell lymphoma patients: an Italian retrospective multicenter study

Relapsed or refractory diffuse large B-cell lymphoma (DLBCL) not suitable for high dose chemotherapy with autologous stem cell transplantation (ASCT) has a dismal prognosis and no standard therapy. We designed an Italian multicenter retrospective study aimed at evaluating the safety and efficacy of rituximab plus bendamustine (R-B) as salvage treatment in patients not eligible for ASCT because of age and/or comorbidity or in patients with post-ASCT recurrence. Fifty-five patients with a median age of 76 years were included. The overall response rate was 50%, including 28% complete remission and 22% partial remission. The median overall survival (OS) was 10.8 months. The median progression free survival (PFS) was 8.8 months. Eleven patients are still alive and in complete remission at last follow-up (12-71 months). Toxicity was moderate, mainly grades 1 and 2. R-B showed promising efficacy results with an acceptable toxicity profile and should be further investigated, possibly in combination with novel drugs.

Optimal use of bendamustine in hematologic disorders: Treatment recommendations from an international consensus panel - an update

Bendamustine has achieved widespread international regulatory approval and is a standard agent for the treatment for chronic lymphocytic leukemia (CLL), indolent non-Hodgkin lymphoma and multiple myeloma. Since approval, the number of indications for bendamustine has expanded to include aggressive non-Hodgkin lymphoma and Hodgkin lymphoma and novel targeted therapies, based on new bendamustine regimens/combinations, are being developed against CLL and lymphomas. In 2010, an international panel of bendamustine experts met and published a set of recommendations on the safe and effective use of bendamustine in patients suffering from hematologic disorders. In 2014, this panel met again to update these recommendations since the clarification of issues including optimal dosing and management of bendamustine-related toxicities. The aim of this report is to communicate the latest consensus on the use of bendamustine, permitting the expansion of its safe and effective administration, particularly in new combination therapies.

Pharmacokinetic and pharmacodynamic profile of bendamustine and its metabolites

Purpose

Bendamustine is a unique alkylating agent indicated for the treatment of chronic lymphocytic leukemia and rituximab-refractory, indolent B cell non-Hodgkin’s lymphoma. Despite the extensive experience with bendamustine, its pharmacokinetic profile has only recently been described. This overview summarizes the pharmacokinetics, pharmacokinetic/pharmacodynamic relationships, and drug–drug interactions of bendamustine in adult and pediatric patients with hematologic malignancies.

Methods

A literature search and data on file (including a human mass balance study, pharmacokinetic population analyses in adult and pediatric patients, and modeling analyses) were evaluated for inclusion.

Results

Bendamustine concentrations peak at end of intravenous infusion (~1 h). Subsequent elimination is triphasic, with the intermediate t_1/2 (~40 min) as the effective t_1/2 since the final phase represents <1 % of the area under the curve. Bendamustine is rapidly hydrolyzed to monohydroxy-bendamustine and dihydroxy-bendamustine, which have little or no activity. Cytochrome P450 (CYP) 1A2 oxidation yields the active metabolites γ-hydroxybendamustine and N-desmethyl-bendamustine, at low concentrations, which contribute minimally to cytotoxicity. Minor involvement of CYP1A2 in bendamustine elimination suggests a low likelihood of drug–drug interactions with CYP1A2 inhibitors. Systemic exposure to bendamustine 120 mg/m² is comparable between adult and pediatric patients; age, race, and sex have been shown to have no significant effect on systemic exposure in either population. The effect of hepatic/renal impairment on bendamustine pharmacokinetics remains to be elucidated. Higher bendamustine concentrations may be associated with increased probability of nausea or infection. No clear exposure–efficacy response relationship has been observed.

Conclusions

Altogether, the findings support dosing based on body surface area for most patient populations.

Prognostic significance of metabolic tumor burden by positron emission tomography/computed tomography in patients with relapsed/refractory diffuse large B-cell lymphoma

The aim of the present study was to investigate the feasibility of measuring metabolic tumor burden using [F-18] fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) treated with bendamustine–rituximab. Because the standardized uptake value is a critical parameter of tumor characterization, we carried out a phantom study of ¹⁸F-FDG PET/CT to ensure quality control for 28 machines in the 24 institutions (Japan, 17 institutions; Korea, 7 institutions) participating in our clinical study. Fifty-five patients with relapsed or refractory DLBCL were enrolled. The ¹⁸F-FDG PET/CT was acquired before treatment, after two cycles, and after the last treatment cycle. Treatment response was assessed after two cycles and after the last cycle using the Lugano classification. Using this classification, remission was complete in 15 patients (27%) and incomplete in 40 patients (73%) after two cycles of therapy, and remission was complete in 32 patients (58%) and incomplete in 23 patients (42%) after the last treatment cycle. The percentage change in all PET/CT parameters except for the area under the curve of the cumulative standardized uptake value–volume histogram was significantly greater in complete response patients than in non-complete response patients after two cycles and the last cycle. The Cox proportional hazard model and best subset selection method revealed that the percentage change of the sum of total lesion glycolysis after the last cycle (relative risk, 5.24; P = 0.003) was an independent predictor of progression-free survival. The percent change of sum of total lesion glycolysis, calculated from PET/CT, can be used to quantify the response to treatment and can predict progression-free survival after the last treatment cycle in patients with relapsed or refractory DLBCL treated with bendamustine–rituximab.

An evaluation of the potential for drug-drug interactions between bendamustine and rituximab in indolent non-Hodgkin lymphoma and mantle cell lymphoma

PURPOSE

Bendamustine plus rituximab has been reported to be effective in treating lymphoid malignancies. This analysis investigated the potential for drug-drug interactions between the drugs in patients with indolent non-Hodgkin lymphoma or mantle cell lymphoma.

METHODS

Data were derived from a bendamustine-rituximab combination therapy study, a bendamustine monotherapy study, and published literature on rituximab monotherapy and combination therapy. Analysis of the potential for rituximab to affect bendamustine systemic exposure included comparing bendamustine concentration-time profile following monotherapy to that following combination therapy and comparing model-predicted Bayesian bendamustine clearance in the presence and absence of rituximab. Analysis of the potential for bendamustine to affect rituximab systemic exposure included plotting observed minimum, median, and maximum serum rituximab concentrations at the end of rituximab infusion (EOI) and 24 h and 7 days post-infusion in patients receiving combination therapy versus concentrations reported in literature following rituximab monotherapy.

RESULTS

The established population pharmacokinetic model following bendamustine monotherapy was evaluated to determine its applicability to combination therapy for the purpose of confirming lack of pharmacokinetic interaction. The model adequately described the bendamustine concentration-time profile following monotherapy and combination therapy in adults. There was no statistically significant difference in estimated bendamustine clearance either alone or in combination. Also, rituximab concentrations from EOI to 24 h and 7 days demonstrated a pattern of decline similar to that seen in rituximab studies without bendamustine, suggesting that bendamustine does not affect the rituximab clearance rate.

CONCLUSIONS

Neither bendamustine nor rituximab appears to affect systemic exposure of the other drug when coadministered.

Clinical efficacy and safety in relapsed/refractory diffuse large B-cell lymphoma: a systematic literature review

This systematic literature review was designed to assess information on the clinical efficacy and safety of interventions used in the treatment of refractory or relapsed diffuse large B-cell lymphoma (R/R DLBCL) and to perform a meta-analysis if possible. We searched databases (PubMed, EMBASE, and Cochrane Library for articles from 1997 to August 2, 2012 reported in English), conference abstracts, bibliographic reference lists, and the ClinicalTrials.gov database for phase II to IV studies with results. Studies had to report on patients with R/R DLBCL who were not eligible to receive high-dose therapy (HDT) with stem cell transplantation (SCT) (autologous or allogeneic). Mixed-type non-Hodgkin lymphoma (NHL) studies were required to report R/R DLBCL outcomes separately. We identified 55 studies that presented outcomes data separately for patients with R/R DLBCL. Of 7 comparative studies, only 4 were randomized controlled trials (RCTs). In the 2 RCTs with a common regimen, the patient populations differed too greatly to perform a valid meta-analysis. The 48 single-arm studies identified were typically small (n < 50 in most), with 31% reporting median progression-free survival (PFS) or overall survival (OS) specifically for the R/R DLBCL population. In these studies, median OS ranged from 4 to 13 months. The small number of RCTs in R/R DLBCL precludes identifying optimal treatments. Small sample size, infrequent reporting of OS and PFS separated by histologic type, and limited information on patient characteristics also hinder comparison of results. Randomized studies are needed to demonstrate which current therapies have advantages for improving survival and other important clinical outcomes in patients with R/R DLBCL.

Multicenter Phase II Study of Bendamustine Plus Rituximab in Patients With Relapsed or Refractory Diffuse Large B-Cell Lymphoma

Purpose

Effective and less aggressive therapies are required for patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) who are not eligible for or have undergone autologous stem-cell transplantation (ASCT). The present phase II study assessed the efficacy and safety of bendamustine plus rituximab (BR) in this population.

Patients and Methods

Patients with relapsed or refractory DLBCL treated with one to three prior chemotherapy regimens received rituximab 375 mg/m2 intravenous (IV) infusion on day 1 and bendamustine 120 mg/m2 by IV infusion on days 2 and 3 of each 21-day cycle for up to six cycles. The primary end point was overall response rate (ORR), and the secondary end points were complete response (CR) rate, progression-free survival (PFS), and safety.

Results

Sixty-three patients were enrolled, and 59 received BR. The median age was 67 years (range, 36 to 75 years), and 62.7% of patients were 65 years of age or older. Fifty-seven patients (96.6%) were previously treated with rituximab-containing chemotherapy. The ORR was 62.7% (95% CI, 49.1% to 75.0%), with a CR rate of 37.3% (95% CI, 25.0% to 50.9%). The ORRs were comparable between patients ≥ 65 years of age and less than 65 years (62.2% and 63.6%, respectively). The median PFS was 6.7 months (95% CI, 3.6 to 13.7 months). The most frequently observed grade 3 or 4 adverse events were hematologic: lymphopenia (78.0%), neutropenia (76.3%), leukopenia (72.9%), CD4 lymphopenia (66.1%), and thrombocytopenia (22.0%).

Conclusion

BR is a promising salvage regimen for patients with relapsed or refractory DLBCL after rituximab-containing chemotherapy, warranting further investigation.

Rituximab, bendamustine, and lenalidomide in patients with aggressive B cell lymphoma not eligible for high-dose chemotherapy or anthracycline-based therapy: phase I results of the SAKK 38/08 trial

This phase I trial was designed to develop a new effective and well-tolerated regimen for patients with aggressive B cell lymphoma not eligible for front-line anthracycline-based chemotherapy or aggressive second-line treatment strategies. The combination of rituximab (375 mg/m(2) on day 1), bendamustine (70 mg/m(2) on days 1 and 2), and lenalidomide was tested with a dose escalation of lenalidomide at three dose levels (10, 15, or 20 mg/day) using a 3 + 3 design. Courses were repeated every 4 weeks. The recommended dose was defined as one level below the dose level identifying ≥2/6 patients with a dose-limiting toxicity (DLT) during the first cycle. Thirteen patients were eligible for analysis. Median age was 77 years. WHO performance status was 0 or 1 in 12 patients. The Charlson Comorbidity Index showed relevant comorbidities in all patients. Two DLTs occurred at the second dose level (15 mg/day) within the first cycle: one patient had prolonged grade 3 neutropenia, and one patient experienced grade 4 cardiac adverse event (myocardial infarction). Additional grade 3 and 4 toxicities were as follows: neutropenia (31 %), thrombocytopenia (23 %), cardiac toxicity (31 %), fatigue (15 %), and rash (15 %). The dose of lenalidomide of 10 mg/day was recommended for a subsequent phase II in combination with rituximab 375 mg/m(2) on day 1 and bendamustine 70 mg/m(2) on days 1 and 2.

Dose dependent effects on cell cycle checkpoints and DNA repair by bendamustine

Bendamustine (BDM) is an active chemotherapeutic agent approved in the U. S. for treating chronic lymphocytic leukemia and non-Hodgkin lymphoma. Its chemical structure suggests it may have alkylator and anti-metabolite activities; however the precise mechanism of action is not well understood. Here we report the concentration-dependent effects of BDM on cell cycle, DNA damage, checkpoint response and cell death in HeLa cells. Low concentrations of BDM transiently arrested cells in G2, while a 4-fold higher concentration arrested cells in S phase. DNA damage at 50, but not 200 µM, was efficiently repaired after 48 h treatment, suggesting a difference in DNA repair efficiency at the two concentrations. Indeed, perturbing base-excision repair sensitized cells to lower concentrations of BDM. Timelapse studies of the checkpoint response to BDM showed that inhibiting Chk1 caused both the S- and G2-arrested cells to prematurely enter mitosis. However, whereas the cells arrested in G2 (low dose BDM) entered mitosis, segregated their chromosomes and divided normally, the S-phase arrested cells (high dose BDM) exhibited a highly aberrant mitosis, whereby EM images showed highly fragmented chromosomes. The vast majority of these cells died without ever exiting mitosis. Inhibiting the Chk1-dependent DNA damage checkpoint accelerated the time of killing by BDM. Our studies suggest that BDM may affect different biological processes depending on drug concentration. Sensitizing cells to killing by BDM can be achieved by inhibiting base-excision repair or disrupting the DNA damage checkpoint pathway.

Novel therapies for aggressive B-cell lymphoma

Aggressive B-cell lymphoma (BCL) comprises a heterogeneous group of malignancies, including diffuse large B-cell lymphoma (DLBCL), Burkitt lymphoma, and mantle cell lymphoma (MCL). DLBCL, with its 3 subtypes, is the most common type of lymphoma. Advances in chemoimmunotherapy have substantially improved disease control. However, depending on the subtype, patients with DLBCL still exhibit substantially different survival rates. In MCL, a mature B-cell lymphoma, the addition of rituximab to conventional chemotherapy regimens has increased response rates, but not survival. Burkitt lymphoma, the most aggressive BCL, is characterized by a high proliferative index and requires more intensive chemotherapy regimens than DLBCL. Hence, there is a need for more effective therapies for all three diseases. Increased understanding of the molecular features of aggressive BCL has led to the development of a range of novel therapies, many of which target the tumor in a tailored manner and are summarized in this paper.