The discovery and the development of bendamustine for the treatment of non-Hodgkin lymphoma

Phase 1 Study Evaluating Pharmacokinetics and Tolerability of Ofatumumab Combined With Bendamustine in Patients With Indolent B-Cell Non-Hodgkin's Lymphoma

The pharmacokinetics (PK) and safety of ofatumumab and bendamustine alone and in combination were evaluated in patients with treatment-naive or relapsed indolent B-cell non-Hodgkin lymphoma (iNHL). Patients were randomly assigned to ofatumumab and bendamustine or ofatumumab alone. Ofatumumab PK concentration profiles and parameters were similar, alone or in combination with bendamustine. A decrease of 14% in the maximum observed plasma concentration (C_max ) and 15% in the area under the plasma concentration-time curve (AUC) from time 0 to the last measurable concentration sampling time (AUC_last ) was observed for ofatumumab coadministered with bendamustine, which was not considered clinically relevant. Bendamustine PK concentration profiles and parameters were similar with or without ofatumumab. The most frequent treatment-related adverse event was infusion-related reaction in 53% in the combination arm and 47% in the ofatumumab arm. No relevant drug-drug interaction was observed between ofatumumab and bendamustine. Ofatumumab alone or in combination with bendamustine had a manageable safety profile.

The potential efficacy and mechanism of bendamustine in entra-nodal NK/T cell lymphoma

Bendamustine has been shown to have anti-tumor activities in hematological malignancies, but the role of bendamustine in natural killer (NK)/T cell lymphoma (NKTCL) treatment is unclear. Our study has shown that bendamustine had potent growth-inhibitory and apoptosis-inducing effects on NKTCL cells. Interestingly, we noticed that the combination of either gemcitabine or etoposide results in additive or synergistic cytotoxicity. Bendamustine induced mitochondria-mediated apoptosis in concentration- and time-dependent manners in NKTCL cells, shown as down-regulation of Bcl-2 and activation of cleavage of caspases 3, 7, 9 and poly adenosinediphosphate-ribose polymerase (PARP). Bendamustine arrested NKTCL cells in G2/M phase, with downregulation of expression of cyclin B1 and upregulation of expression of p-cdc2, p-cdc25c and p-P53. Furthermore, we confirmed that bendamustine activated DNA damage response (DDR) directly or through Ataxia Telangiectasia Mutated Protein (ATM)/Chk2 and ATR/Chk1 pathway and increased the intracellular reactive oxygen species (ROS) level in NKTCL cells, which caused G2/M phase arrest and apoptosis. Bendamustine also inhibited phosphorylation of transcriptional factor STAT3, contributing to cell apoptosis and proliferation inhibition. Finally, we verified the effect of bendamustine on NKTCL cells in vivo. It showed that bendamustine dramatically inhibited the growth of the subcutaneous tumor, with no obvious impact on mice weight. These findings demonstrate that bendamustine activates DDR pathway, induces the accumulation of intracellularROS level as well as inhibition of STAT3, leading to cell apoptosis and G2/M cell cycle arrest in NKTCL cells, which indicates that bendamustine dramatically suppressed NKTCL both in vitro and in vivo and provides a potential therapeutic strategy in the treatment of NK/T lymphoma.

Clinical Efficacy of Bendamustine Plus Rituximab (BR) for B-cell Relevant Indolent Non-Hodgkin’s Lymphoma and Role of β2-MG in Predicting the Efficacy of BR Regimen: A Real-World Retrospective Study in China

Background. Domestic bendamustine has been approved for appearing on the market in China in the past two years. The report on bendamustine plus rituximab (BR) in the treatment of Chinese B-cell-associated indolent non-Hodgkin’s lymphoma (iNHL) has not yet been published. This study probed into clinical efficacy of the BR regimen for B-cell-associated iNHL in China as well as the value of β2-microglobulin (β2-MG) as a prognostic factor. Methods. We retrospectively analyzed clinical data of 73 B-cell-associated iNHL patients who received BR treatment in The First Affiliated Hospital, College of Medicine, Zhejiang University from January 2020 to January 2021, including clinical characteristics, therapies, therapeutic efficacy, and prognosis-related factors. Thirty-three patients (45.2%) did not receive any other treatment before the BR regimen, and other patients received CHOP, R-CHOP, and other regimens in the past. The cutoff date for follow-up was May 2021. Clinical characteristics of patients were analyzed. The clinical efficacy of the BR regimen was evaluated. Differences of β2-MG expression before and after treatment were analyzed between the CR+PR group and the SD+PD group. Main outcomes were progression-free survival (PFS) and overall survival (OS). A multivariate Cox regression model was taken to analyze prognostic factors relative to survival rate of patients, and adverse events (AEs) during treatment. Results. The objective response rate (ORR) of B-cell-associated iNHL patients who received BR regimen as first-/multiline treatment was 79.5%, with complete response (CR) of 37.0%, partial response (PR) of 42.5%, median PFS of 12.1 months (95% confidence interval (CI): 10.9-13.2), and median OS of 15.5 months (95% CI: 14.8-16.1). Before treatment, there was no statistical significance in the β2-MG level between the CR+PR group and the SD+PD group ( $p>0.05$ ). After treatment, the β2-MG level in the CR group was noticeably lower than that in the SD+PD group ( $p<0.05$ ). The β2-MG level in the CR+PR group decreased conspicuously after treatment ( $p<0.05$ ). The β2-MG level in the SD+PD group after treatment was not notably different from that before treatment ( $p>0.05$ ). According to the median expression level of β2-MG before treatment, patients were divided into two groups. The average PFS of the low expression group was $12.69\pm 0.77$ months, which was longer than the high expression group ( $10.13\pm 0.74$ months), but the difference between the groups was not statistically significant ( $p>0.05$ ). Multivariate Cox regression analysis showed that B-cell-associated iNHL subtype was the independent prognostic marker most likely to affect PFS of patients ( $p=0.051$ ). Incidence of any grade of AEs in all patients was 32.9% (24/73). Conclusion. B-cell-associated iNHL patients who received BR regimen had favorable clinical efficacy and were tolerable to AEs. Though the β2-MG level in this study could not be used to predict clinical outcome, a lower level before treatment seemed to be implicated in better survival outcomes of patients. Our research also unraveled that B-cell-associated iNHL subtype may be a key factor to patient’s prognosis. Overall, this study offers some important insights into clinical application of the BR regimen for Chinese B-cell-associated iNHL patients.