Methylation of PLK-1 Potentially Drives Bendamustine Resistance in Leukemia Cells.

BACKGROUND: Drug resistance remains a significant impediment in leukemia treatment. While Bendamustine hydrochloride (BH) stands out as a promising therapeutic agent for non-Hodgkin' s lymphoma and mantle cell lymphoma, the mechanisms of resistance to BH are not yet fully understood. Our study focuses on elucidating the mechanisms behind bendamustine resistance in leukemia cells, with a specific emphasis on epigenetics. METHODS: Bendamustine-resistant cells were cultivated from human B cell lymphoblastic leukemia cell lines through systematic and sustained exposure to bendamustine, using the limiting dilution method. Gene expression was assessed via real-time polymerase chain reaction, while the expression of the multidrug resistance protein 1 (MDR1) was evaluated using flow cytometry. RESULTS: Bendamustine-resistant leukemia cells exhibited a decreased RNA expression level for Polo-like kinase-1 (PLK-1). Notably, after treatment with the demethylating agent 5-aza-2'-deoxycytidine, PLK-1 gene expression surged significantly, enhancing bendamustine's cytotoxicity in the resistant leukemia cells. However, MDR1 expression, as determined by flow cytometry, remained consistent between parental and bendamustine-resistant leukemia cells. CONCLUSIONS: Our findings indicate that the methylation of the PLK-1 gene plays a pivotal role in modulating PLK-1 expression and is central to the development of bendamustine resistance in leukemia cells.

[Bendamustine combined with pomalidomide and dexamethasone in relapsed multiple myeloma with extramedullary disease: a multicenter study].

Objective: To evaluate the efficacy and safety of bendamustine combined with pomalidomide and dexamethasone (BPD regimen) in the treatment of relapsed multiple myeloma (MM) with extramedullary disease. Methods: This open, single-arm, multicenter prospective cohort study included 30 relapsed MM patients with extramedullary disease diagnosed in seven hospitals including Qingdao Municipal Hospital. The patients were treated with BPD regimen from February 2021 to November 2022. This study analyzed the efficacy and adverse reactions of the BPD regimen. Results: The median age of the 30 patients was 62 (47-72) years, of which 18 (60% ) had first-time recurrence. The overall response rate (ORR) of the 18 patients with first-time recurrence was 100%, of which three (16.7% ) achieved complete remission, 10 (55.5% ) achieved very good partial remission (VGPR), and five (27.8% ) achieved partial remission (PR). The ORR of 12 patients with recurrence after second-line or above treatment was 50%, including zero patients with ≥VGPR and six patients (50% ) with PR. Three cases (25% ) had stable disease, and three cases (25% ) had disease progression. The one-year progression free survival rate of all patients was 65.2% (95% CI 37.2% -83.1% ), and the 1-year overall survival rate was 90.0% (95% CI 76.2% -95.4% ). The common grade 3-4 hematology adverse reactions included two cases (6.7% ) of neutropenia and one case (3.3% ) of thrombocytopenia. The overall adverse reactions are controllable. Conclusions: The BPD regimen has good efficacy and tolerance in relapsed MM patients with extramedullary disease.

Safety and efficacy of parsaclisib in combination with obinutuzumab and bendamustine in patients with relapsed or refractory follicular lymphoma (CITADEL-102): A phase 1 study.

Parsaclisib is a potent and highly selective PI3Kδ inhibitor that has shown clinical benefit with monotherapy in a phase 2 study in relapsed or refractory (R/R) follicular lymphoma (FL). CITADEL-102 (NCT03039114), a phase 1, multicenter study, assessed the efficacy of parsaclisib in combination with obinutuzumab and bendamustine in patients with R/R FL. Patients were ≥18 years of age with histologically confirmed and documented CD20-positive FL, and R/R to previous rituximab-containing treatment regimens. Part one (safety run-in) determined the maximum tolerated dose of parsaclisib in combination with standard dosage regimens of obinutuzumab and bendamustine. Part two (dose expansion) was an open-label, single-group design evaluating safety, tolerability (primary endpoint), and efficacy (secondary endpoint) of parsaclisib combination therapy. Twenty-six patients were enrolled in CITADEL-102 and all patients received parsaclisib 20 mg once daily for 8 weeks, followed by 20 mg once weekly thereafter, in combination with obinutuzumab and bendamustine. One patient in safety run-in experienced a dose-limiting toxicity of grade 4 QT interval prolongation that was considered related to parsaclisib. Eight patients (30.8%) discontinued treatment due to treatment-emergent adverse events (TEAEs) of colitis (2 [7.7%]), alanine aminotransferase and aspartate aminotransferase increase (both in one patient [3.8%]), neutropenia, thrombocytopenia, QT prolongation, tonsil cancer, and maculopapular rash (each 1 [3.8%]). The most common reported TEAEs were pyrexia (53.8%), neutropenia (50.0%), and diarrhea (46.2%). Twenty-three patients (88.5%) experienced grade 3 or 4 TEAEs; the most common were neutropenia (34.6%), febrile neutropenia (23.1%), and thrombocytopenia (19.2%). Seventeen patients (65.4%) had a complete response and 3 patients (11.5%) had a partial response, for an objective response rate of 76.9%. Overall, results from CITADEL-102 suggest that the combination of parsaclisib with obinutuzumab and bendamustine did not result in unexpected safety events, with little evidence of synergistic toxicity, and demonstrated preliminary efficacy in patients with R/R FL who progressed following prior rituximab-containing regimens.

Bendamustine combined with pomalidomide and dexamethasone in relapsed multiple myeloma with extramedullary disease: a multicenter study / 中华血液学杂志

Objective: To evaluate the efficacy and safety of bendamustine combined with pomalidomide and dexamethasone (BPD regimen) in the treatment of relapsed multiple myeloma (MM) with extramedullary disease. Methods: This open, single-arm, multicenter prospective cohort study included 30 relapsed MM patients with extramedullary disease diagnosed in seven hospitals including Qingdao Municipal Hospital. The patients were treated with BPD regimen from February 2021 to November 2022. This study analyzed the efficacy and adverse reactions of the BPD regimen. Results: The median age of the 30 patients was 62 (47-72) years, of which 18 (60% ) had first-time recurrence. The overall response rate (ORR) of the 18 patients with first-time recurrence was 100%, of which three (16.7% ) achieved complete remission, 10 (55.5% ) achieved very good partial remission (VGPR), and five (27.8% ) achieved partial remission (PR). The ORR of 12 patients with recurrence after second-line or above treatment was 50%, including zero patients with ≥VGPR and six patients (50% ) with PR. Three cases (25% ) had stable disease, and three cases (25% ) had disease progression. The one-year progression free survival rate of all patients was 65.2% (95% CI 37.2% -83.1% ), and the 1-year overall survival rate was 90.0% (95% CI 76.2% -95.4% ). The common grade 3-4 hematology adverse reactions included two cases (6.7% ) of neutropenia and one case (3.3% ) of thrombocytopenia. The overall adverse reactions are controllable. Conclusions: The BPD regimen has good efficacy and tolerance in relapsed MM patients with extramedullary disease.

Bendamustine and pneumocystis pneumonia: A systematic review.

Background: Bendamustine, a bifunctional mechlorethamine alkylating agent, is used in the treatment of patients with hematologic malignancies. Myelosuppression and cytotoxic effect arises quite often after bendamustine treatment. To date, there have been no recommendations for routine chemoprophylaxis for Pneumocystis carinii pneumonia (PCP) in patients under treatment with this agent. The present systematic review aimed to evaluate the existing data on bendamustine effects on pneumocystis pneumonia. Method: English papers were systematically reviewed using Web of Science, Embase, Google Scholar, PubMed, and Cochrane library. There was no time constraint for the paper search. The used keywords included "Pneumonia, Pneumocystis"or "Pneumocystis Pneumonia"or "Pneumocystis jirovecii" and "Bendamustine hydrochloride or Bendamustine. "Through our search, 113 papers were found, 26 of which were chosen following a review of the titles and abstracts; ultimately, 10 were included in the research. Result: A total of 10 studies (out of 113 studies) were retrieved. The papers were classified into seven case reports, two clinical trials, and one retrospective analysis study. The case reports included 14 patients diagnosed with PCP after bendamustine administration between 2003 and 2019. The patients' mean age was with a range of 66.8. Non-Hodgkin's lymphoma (including diffuse large B-cell lymphoma and mantle cell lymphoma) (n = 9, 60%), chronic lymphocytic leukemia (n = 4, 26.6%), and breast cancer (n = 2, 13.4%) were the most prevalent types of malignancy. Bendamustine, along with rituximab, were the most commonly prescribed chemotherapy regimens during the treatments. Finally, the mortality rate among the patients whose results were reported (n = 9) was 44.44% (n = 4). Conclusion: The present review described PCP infection in patients with malignancies after the treatment with bendamustine, a chemotherapeutic agent associated with lymphopenia. Further research is required to determine the PCP risk in patients with bendamustine treatment and identify individuals who may benefit from prophylaxis.

Bendamustine: A review of pharmacology, clinical use and immunological effects (Review).

Bendamustine is an alkylating agent classified into the group of nitrogen mustard analogues, synthesized almost sixty years ago. It was registered in former East Germany in 1971 and approved by the US Food and Drug Administration in 2008 for treatment of chronic lymphocytic leukemia and indolent B­cell non­Hodgkin lymphoma. Considering its beneficial properties in the therapy of relapsed or refractory hematological malignancies, synergistic effects with other antineoplastic agents and increasing recent reports on its immunomodulatory effects, bendamustine has once again gained its justified attention. The uniqueness of bendamustine­mediated effects should be observed keeping in mind its distinctive structure with structural similarities to both alkylating agents and purine analogs. In the present review, the current knowledge on the use of bendamustine in oncology, its pharmacokinetics, mechanism of action and toxicity was summarized. In addition, its immune­modulating effects that have not been fully elucidated so far are emphasized, hoping to encourage further investigations of this unique drug.

Bendamustine plus rituximab in Japanese patients with relapsed or refractory diffuse large B-cell lymphoma.

This single-arm phase 3 study was conducted to confirm the results of our phase 2 study of bendamustine (B)-rituximab (R) in patients with relapsed/refractory diffuse large B cell lymphoma (rrDLBCL). The primary endpoint was overall response rate (ORR). Autologous stem cell transplantation-ineligible rrDLBCL patients with ≤ 2 prior chemotherapy regimens received R 375 mg/m2 IV on day 1 and B 120 mg/m2/day IV on days 2 and 3 every 21 days up to 6 cycles. Thirty-eight patients with a median age of 74 years (range, 43-86) received BR. The ORR and complete response rates were 76.3% and 47.4%, respectively. With a median follow-up of 19.5 months including long-term follow-up, median progression-free survival was 11.9 months. Median OS was 29.2 months. Discontinuation of treatment due to Gr3-5 TEAE was observed among 13 of 38 patients (34.2%). One patient with cytomegalovirus enterocolitis died during follow-up. This BR regimen was confirmed to be effective and tolerable in studied patients. ClinicalTrials.gov Identifier: NCT03372837 registered on 14 December 2017, NCT04354402 registered on 21 April, 2020.

Brentuximab vedotin in association with bendamustine in refractory or multiple relapsed Hodgkin lymphoma. A retrospective real-world study.

OBJECTIVE AND METHODS: In order to assess the efficacy of brentuximab vedotin (Bv) in combination with bendamustine (B) in multiple relapsed or refractory (RR) classic Hodgkin lymphoma (cHL), medical records of 47 patients treated with BvB in second relapse or beyond were reviewed. RESULTS: The median number of previous treatments was 2 (1-4). Bv was given at 1.8 mg/kg on day 1 and bendamustine at 90 mg/m2 on days 1 and 2 of a 21-day cycle. The median number of BvB cycles was 4 (2-7), and all patients were evaluable for efficacy. The CR and OR rates were 49% and 79%, respectively; 67% of responding patients and 2 in stable disease proceeded to a SCT procedure. After a median follow-up of 19 months (5-47), median PFS was 18 months (95%CI: 23-29), and the 2-year OS was 72%. Significantly longer PFS and OS were observed in patients attaining a major clinical response to treatment and in those who received consolidation with SCT. Fifteen (32%) patients experienced severe (G > 2) toxicity. The main toxicities were neutropenia (23%), gastrointestinal (10%), peripheral sensory neuropathy (11%), and infection (4%). CONCLUSION: Our real-world results suggest that BvB is an effective third-line rescue and bridge-to-transplant regimen for RR-cHL patients.

Nitrogen Mustards as Alkylating Agents: A Review on Chemistry, Mechanism of Action and Current USFDA Status of Drugs.

BACKGROUND & OBJECTIVE: Nitrogen mustard derivatives form one of the major classes of anti-cancer agents in USFDA approved drugs list. These are polyfunctional alkylating agents which are distinguished by a unique mechanism of adduct formation with DNA involving cross-linking between guanine N-7 of one strand of DNA with the other. The generated cross-linking is irreversible and leads to cell apoptosis. Hence it is of great interest to explore this class of anticancer alkylating agents. METHODS: An exhaustive list of reviews, research articles, patents, books, patient information leaflets, and orange book is presented and the contents related to nitrogen mustard anti-cancer agents have been reviewed. Attempts are made to present synthesis schemes in a simplified manner. The mechanism of action of the drugs and their side effects are also systematically elaborated. RESULTS: This review provides a platform for understanding all aspects of such drugs right from synthesis to their mechanism of action and side effects, and lists USFDA approved ANDA players among alkylating anticancer agents in the current market. CONCLUSION: Perusing this article, generic scientists will be able to access literature information in this domain easily to gain insight into the nitrogen mustard alkylating agents for further ANDA development. It will help the scientific and research community to continue their pursuit for the design of newer and novel heterocyclic alkylating agents of this class in the coming future.

Polymorphic forms of bendamustine hydrochloride: crystal structure, thermal properties and stability at ambient conditions.

Crystallographic, thermal and stability analyses are presented of three different anhydrated forms of bendamustine hydrochloride [(I), (III) and (IV)] and a fourth, monohydrated one (II). Since form (I) presents the higher melting point and the higher heat of fusion, according to the `heat of fusion' rule it should be the most stable in thermodynamic terms [Burger & Ramberger (1979). Mikrochim. Acta, 72, 259-271], though it is unstable in high-humidity conditions. The monohydrate structure (II), in turn, dehydrates by heating and topotactically transform into anhydrate (III). This latter form appears as less stable than anhydrate (I), to which it is linked via a monotropic relationship. For these three different forms, the crystal structure has been determined by single crystal X-ray diffraction. The crystal structures and molecular conformations of forms (II) and (III) are quite similar, as expected from the topotactic transformation linking them; furthermore, under high-humidity conditions, form (III) shows changes compatible with a transformation into form (II) within 24 h. The crystal structure of form (I) is different from the other two. The remaining polymorphic form (IV) could only be obtained as a powder, from which its crystalline structure could not be determined. The relative thermodynamic stability of the different crystalline forms was determined by differential scanning calorimetry and thermogravimetrical studies, and their stability under different humidity conditions analysed.

Box-Behnken Design of Experiment Assisted Development and Optimization of Bendamustine HCl loaded Hydroxyapatite Nanoparticles.

BACKGROUND: Bendamustine HCl, an antineoplastic drug, has a very short life of about 40 minutes which necessitates administration of large doses which leads to increased side effects as well as costs. OBJECTIVE: The present work describes the fabrication, optimization, and evaluation of bioactive hydroxyapatite nanoparticles to achieve sustained delivery of bendamustine HCl. METHODS: Hydroxyapatite nanoparticles (NPs) were prepared by the wet chemical precipitation method by reacting a calcium and phosphate precursor and the reaction was optimized via Box-Behnken DOE. The drug was loaded on particles by physical adsorption. Various analytical studies were performed on the fabricated nanoparticles in addition to biodistribution studies to establish the physicochemical and biological characteristics of the designed formulation. RESULTS: pH of the reactant solution was found to have a more profound effect on the particle size and size distribution in comparison to reactant concentration. The particles were found to have a spherical morphology by SEM. Size of the blank and drug-loaded nanoparticles was found to be 130±20 nm by TEM. Energy Dispersive X-ray Spectroscopy (EDS) studies confirmed the presence of hydroxyapatite as the dominant phase while DSC studies indicated the presence of the drug in its amorphous form after its adsorption on NPs. Tissue distribution studies further suggested that the majority of drug concentration was released in blood rather than the other organs implying low organ toxicity. CONCLUSION: Bendamustine loaded hydroxyapatite nanoparticles were successfully optimized and fabricated. Favorable results were obtained in in vitro, in vivo, and analytical studies.

BENDAMUSTINE: AN OLD DRUG IN THE NEW ERA FOR PATIENTS WITH NON-HODGKIN LYMPHOMAS AND CHRONIC LYMPHOCYTIC LEUKEMIA.

- The aim of this review is to present data on bendamustine, a non-cross resistant alkylating agent, alone or in combination for treatment of non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL). Bendamustine is currently approved for rituximab-resistant indolent NHL and CLL in patients not fit for conventional chemotherapy. Recent studies have shown superiority of bendamustine combination with rituximab (B-R) in first line treatment of indolent NHLs and mantle cell lymphoma, suggesting a shift of the standard of care in this setting. B-R regimen has also shown efficacy in relapsed setting suggesting the possible treatment option for patients failing conventional chemotherapy. In rituximab-resistant NHL, the recent GADOLIN study exploring the addition of obinutuzumab to bendamustine has yielded impressive result changing the standard of care in this hard-to-treat population. Concerning CLL, despite inferiority to the standard of care in young fit patients, as defined in CLL10 study, B-R has yielded a more beneficial toxicity profile and its use in first line treatment should be decided individually. In relapsed setting, the addition of ibrutinib to B-R has shown superior results compared to B-R alone, possibly changing the paradigm of treatment of relapsed CLL. In conclusion, bendamustine as a single agent or in combinations has shown activity with acceptable toxic profile in the treatment of patients with indolent NHLs or CLL without del(17p) mutation.

Nanosized complexation assemblies housed inside reverse micelles churn out monocytic delivery cores for bendamustine hydrochloride.

OBJECTIVE: We explore a plausible method of targeting bendamustine hydrochloride (BM) to circulatory monocytes by exploiting their intrinsic endocytic/phagocytic capability. METHODS: We do so by complexation of sodium alginate and chitosan inside dioctyl sulfo succinate sodium (AOT) reverse micelles to form bendamustine hydrochloride loaded nanoparticles (CANPs). Dynamic light scattering, electrophoretic mobility and UV spectroscopy were used to detail intra-micellar complexation dynamics and to prove that drug was co-captured during interaction of carbohydrate polymers. A fluorescent conjugate of drug (RBM) was used to trace its intracellular fate after its loading into nanoparticles. RESULTS: CANPs were sized below 150nm, had 75% drug entrapment and negative zeta potential (-30mV). Confocal microscopy demonstrated that developed chitosan alginate nanoparticles had the unique capability to carry BM specifically to its site of action. Quantitative and mechanism based cell uptake studies revealed that monocytes had voracious capacity to internalize CANPs via simultaneous scavenger receptor based endocytic and phagocytic mechanism. Comparative in vitro pharmacokinetic studies revealed obtainment of significantly greater intracellular drug levels when cells were treated with CANPs. This caused reduction in IC50 (22.5±2.1µg/mL), enhancement in G2M cell cycle arrest, greater intracellular reactive oxygen species generation, and increased apopotic potential of bendamustine hydrochloride in THP-1 cells. CONCLUSION: Selective monocytic targeting of bendamustine hydrochloride using carbohydrate constructs can prove advantageous in case of leukemic disorders displaying overabundance of such cells.

Synergistic anticancer efficacy of Bendamustine Hydrochloride loaded bioactive Hydroxyapatite nanoparticles: In-vitro, ex-vivo and in-vivo evaluation.

The present work evaluates the synergistic anticancer efficacy of bioactive Hydroxyapatite (HA) nanoparticles (HA NPs) loaded with Bendamustine HCl. Hydroxyapatite is a material with an excellent biological compatibility, a well-known fact which was also supported by the results of the Hemolytic studies and a high IC50 value observed in the MTT assay. HA NPs were prepared by the chemical precipitation method and loaded with the drug via physical adsorption. In-vitro release study was performed, which confirmed the sustained release of the drug from the drug loaded HA NPs. MTT assay, Cell Uptake and FACS studies on JURKAT E6.1 cell line and in-vivo pharmacokinetic studies in Wistar rats revealed that the drug loaded HA NPs could be easily internalized by the cells and release drug in a sustained manner. The drug loaded HA NPs showed cytotoxicity similar to the drug solution at 1/10th of the drug content, which indicates a possible synergism between the activity of the anticancer drug and calcium ions derived from the carrier. An increase in intracellular Ca(2+) ions is reported to induce apoptosis in cells. Tumor regression study in Balb/c mice Ehrlich's ascites model presented a similar synergistic efficacy. The drug solution was able to decrease the tumor volume by half, while the drug loaded HA NPs reduced the tumor size by 6 times.

Determination of Residual Palladium in Bendamustine Hydrochloride by GFAAS / 中国药师

Objective:To develop a method for the determination of palladium in bendamustine hydrochloride by GFAAS. Meth-ods:The sample was destroyed by heat, and the content of palladium was determined by GFAAS with the detection wavelength of 247. 6 nm. Results:The absorbance and the content of palladium showed a good linear relationship within the range of 20-60 ng· ml-1(r=0. 998 4). The average recovery of palladium was 102. 9%(RSD=1. 7%, n=9). Conclusion: The method is sensitive and simple, which can be used for the determination of palladium in bendamustine hydrochloride.

Identification of the related substances in bendamustine hydrochloride / 中国药科大学学报

@#In the HPLC analysis of bendamustine hydrochloride, two related substances(IMP01 and IMP02)were detected. These two related substances were identified by LC-MS/MS and their structural confirmation was unambiguously carried out by synthesis followed by characterization using Q-TOF/MS and NMR. Based on the spectral data, related substances IMP01 and IMP02 were characterized as 4-(1-methyl-5-morpholino-1H-benzo［d］imidazol-2-yl)butyric acid hydrochloride and 4-{1-methyl-5-［(2-chloroethyl)(2-hydroxyethyl)amino］-1H-benzo［d］imidazol-2-yl)} butyric acid hydrochloride, respectively. Bendamustine hydrochloride and its related substances were separated under the established LC-MS condition. HPLC is a useful method for the determination of the related substances in bendamustine hydrochloride. Results obtained are valuable for its manufacturing process and quality control.

Efficacy of bendamustine hydrochloride in patients with rituximab-refractory indolent B-cell non-Hodgkin's lymphoma：results from a phaseⅢmulticenter study / 中国肿瘤临床

Objective:To evaluate the efficacy and toxicity of single-agent bendamustine in patients with indolent B-cell non-Hodgkin's lymphoma (NHL) refractory to rituximab. Methods:Between April 2010 and April 2013, 100 patients with rituximab-refrac-tory indolent B-cell NHL from 8 institutions were enrolled. Bendamustine was administered at 120 mg/m2 on days 1 and 2 every 21 days for 6-8 cycles. The primary endpoint was the overall response rate (ORR). The secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Results:One hundred patients with a median age of 56 (rang-ing from 28 to 74) years were recruited in this clinical study. The total number of chemotherapy was 447 cycles, and the median number was 4 cycles. Ninety-three patients could be evaluated for efficacy. Fifteen patients (16.1%) had complete remission (CR), 52 (55.9%) had partial remission (PR), 22 (23.7%) had stable disease (SD), and 4 (4.3%) had progression disease (PD). The ORR and DCR were 72%and 95.7%, respectively. After a median follow-up of 26.6 months (ranging from 2 to 48.4 months), 59 patients (63.4%) had PD.The median PFS was 8.53 (95%CI:6.518-10.542) months, and PFS rate for 1 year was (40.6±5.3)%. Forty-eight patients (48%) had 3/4 grade adverse events, including leucopenia (26%), neutropenia (24%), and anemia (11%). Conclusion:Single-agent bendamustine produced a high rate of objective responses in patients with rituximab-refractory indolent B-cell NHL and could be one of the new op-tions for second-line treatment of these patients. The most common adverse event is hematologic toxicity.

Bendamustine hydrochloride in patients with rituximab-refractory indolent B-cell non-Hodgkin's lymphoma / 中国肿瘤临床

Objective:To observe the clinical efficacy and toxicities of bendamustine hydrochloride in patients with rituximab-re-fractory indolent B-cell non-Hodgkin's lymphoma (NHL). Methods:A total of 25 patients with rituximab-refractory NHL received bendamustine hydrochloride 120 mg/m2 intravenously on days 1 and 2 of the 21-day cycle. The short-term response, progression free survival, and toxicities were evaluated. Results:The total number of chemotherapy of the 25 patients was 122 cycles, and the median number was 5 cycles. All patients could be evaluated for efficacy. Among the patients, 6 had complete remission, 13 had partial remis-sion, 3 had stable disease, and 3 had progression disease. The overall response rate and clinical benefit rate were 76%and 88%, respec-tively. Until the deadline, 13 patients had progression disease. The median duration of response was 8 months, and the median progres-sion-free survival (PFS) was 9.3 months. Subgroup analysis showed that PFS is significantly related to bone marrow involvement and serum LDH level (P<0.05). The main adverse effects were myelosuppression, gastrointestinal reactions, and infection. Rash was found in 2 patients, and 1 case of gastric cancer was discovered after 5 cycles of treatment. Conclusion:Bendamustine hydrochloride was ef-fective and tolerable in patients with rituximab-refractory indolent B-cell NHL.