Therapeutic journery of nitrogen mustard as alkylating anticancer agents: Historic to future perspectives.

Cancer is considered as one of the most serious health problems today. The discovery of nitrogen mustard as an alkylating agent in 1942, opened a new era in the cancer chemotherapy. This valuable class of alkylating agent exerts its biological activity by binding to DNA, cross linking two strands, preventing DNA replication and ultimate cell death. At the molecular level, nitrogen lone pairs of nitrogen mustard generate a strained intermediate "aziridinium ion" which is very reactive towards DNA of tumor cell as well as normal cell resulting in various adverse side effects alogwith therapeutic implications. Over the last 75 years, due to its high reactivity and peripheral cytotoxicity, numerous modifications have been made in the area of nitrogen mustard to improve its efficacy as well as enhancing drug delivery specifically to tumor cells. This review mainly discusses the medicinal chemistry aspects in the development of various classes of nitrogen mustards (mechlorethamine, chlorambucil, melphalan, cyclophosphamide and steroidal based nitrogen mustards). The literature collection includes the historical and the latest developments in these areas. This comprehensive review also attempted to showcase the recent progress in the targeted delivery of nitrogen mustards that includes DNA directed nitrogen mustards, antibody directed enzyme prodrug therapy (ADEPT), gene directed enzyme prodrug therapy (GDEPT), nitrogen mustard activated by glutathione transferase, peptide based nitrogen mustards and CNS targeted nitrogen mustards.

pH-Sensitive PEGylated liposomes for delivery of an acidic dinitrobenzamide mustard prodrug: Pathways of internalization, cellular trafficking and cytotoxicity to cancer cells.

This paper aims to develop and evaluate a pH-sensitive PEGylated liposomal (pPSL) system for tumor-targeted intracellular delivery of SN25860, a weakly acidic, poorly water-soluble dinitrobenzamide mustard prodrug which is activated by the E. coli nitroreductase nfB. pPSL and non pH-sensitive liposomes (nPSL), as reference, were formulated by thin-film hydration; an active drug loading method was developed with the aid of solubilizers. Cytotoxicity was evaluated in an nfsB-transfected EMT6 mouse mammary carcinoma cell line. Cellular uptake of liposomes was evaluated by both high performance liquid chromatography and flow cytometry. Intracellular trafficking was visualised by confocal microscopy. High drug loading (7.0±0.2% w/w) was achieved after systematic optimization of drug loading conditions. pPSL-SN25860 demonstrated a 21 and 24- fold increase in antiproliferative potency compared to nPSL-SN25860 and free drug, respectively. Cells treated with pPSL had a 1.6-2.5- fold increase in intracellular drug concentration compared to nPSL. This trend was consistent with flow cytometry results. Cells treated with chlorpromazine demonstrated reduced uptake of both nPSL (40%) and pPSL (46%), indicating clathrin-mediated endocytosis was the major pathway. Confocal microscopy showed that pPSL had not only undergone faster and greater endocytosis than nPSL but was also homogeneously distributed in the cytosol and nuclei suggesting endosome escape, in contrast to nPSL.

BO-1055, a novel DNA cross-linking agent with remarkable low myelotoxicity shows potent activity in sarcoma models.

DNA damaging agents cause rapid shrinkage of tumors and form the basis of chemotherapy for sarcomas despite significant toxicities. Drugs having superior efficacy and wider therapeutic windows are needed to improve patient outcomes. We used cell proliferation and apoptosis assays in sarcoma cell lines and benign cells; γ-H2AX expression, comet assay, immunoblot analyses and drug combination studies in vitro and in patient derived xenograft (PDX) models. BO-1055 caused apoptosis and cell death in a concentration and time dependent manner in sarcoma cell lines. BO-1055 had potent activity (submicromolar IC50) against Ewing sarcoma and rhabdomyosarcoma, intermediate activity in DSRCT (IC50 = 2-3µM) and very weak activity in osteosarcoma (IC50 >10µM) cell lines. BO-1055 exhibited a wide therapeutic window compared to other DNA damaging drugs. BO-1055 induced more DNA double strand breaks and γH2AX expression in cancer cells compared to benign cells. BO-1055 showed inhibition of tumor growth in A673 xenografts and caused tumor regression in cyclophosphamide resistant patient-derived Ewing sarcoma xenografts and A204 xenografts. Combination of BO-1055 and irinotecan demonstrated synergism in Ewing sarcoma PDX models. Potent activity on sarcoma cells and its relative lack of toxicity presents a strong rationale for further development of BO-1055 as a therapeutic agent.

Redox cycling of a copper complex with benzaldehyde nitrogen mustard-2-pyridine carboxylic acid hydrazone contributes to its enhanced antitumor activity, but no change in the mechanism of action occurs after chelation.

Many anticancer drugs used in the clinical have potent metal chelating ability. The formed metal complex(es) may exhibit improved (or antagonistic) antitumor activity. However, the underlying mechanism has received limited attention. Therefore, investigation of the mechanism involved in the change upon chelation is required to extend our understanding of the effects of various drugs. In the present study, the proliferation inhibition effect of benzaldehyde nitrogen mustard-2-pyridine carboxylic acid hydrazone (BNMPH) and its copper complex on tumor cell lines was investigated. The copper chelate exhibited almost a 10-fold increase in antitumor activity (with IC50 <5 µM). The results showed that both BNMPH and its copper complex induced reactive oxygen species (ROS) generation, and caused upregulation of caspase 8 and Bax as well as the downregulation of Bcl-2, indicating that apoptosis was involved in the cytotoxic effects. DNA fragmentation noted in the comet assay further supported ROS involvement. The present study indicated that BNMPH and its copper complex effectively induced S phase arrest and the cell cycle arrest was associated with the downregulation of cyclin D1. The formation of acidic vesicular organelles (AVOs) and an increase in cleaved LC3-II demonstrated that autophagy occurred in the HepG2 cells treated with the agents. Taken together, BNMPH and its copper complex exhibited proliferation inhibition via apoptosis, cell cycle arrest and autophagy, which was dependent on ROS. The enhanced antitumor activity of the copper complex was due to its redox-cycling ability, but the mechanism was not altered compared to BNMPH. Our findings may significantly contribute to the understanding of the anti-proliferative effect of BNMPH and its copper complex.

Bendamustine as first-line treatment in patients with advanced indolent non-Hodgkin lymphoma and mantle cell lymphoma in German routine clinical practice.

Bendamustine has demonstrated clinical activity and a favorable safety profile as monotherapy or in combination with rituximab in lymphoid malignancies. As interventional trials do not always reflect clinical reality, we were interested in the treatment modalities and the outcome of bendamustine-based first-line therapy in patients with advanced indolent non-Hodgkin lymphoma (NHL) and mantle cell lymphoma (MCL) in routine practice. Between April 2010 and October 2011, 324 patients were enrolled in a prospective non-interventional multicenter study. Choice of the bendamustine regimen was at the treating physician's discretion. Effectiveness was assessed by best response. Mean age at onset of therapy was 69 years. The majority (94 %) of the patients was treated with bendamustine in combination with rituximab at a median bendamustine dose of 177 mg/m(2) per cycle. Most often, bendamustine was administered on days 1 and 2 (87 %) at 4-week intervals over a median of 6 cycles. Two hundred eighty-one patients qualified for evaluation of response. The overall response rate was 86 % (complete response 43 %, partial response 43 %, stable disease 10 %, progressive disease 4 %). Side effects of all grades were documented for 161 of the 323 patients (50 %), most frequently affecting blood/bone marrow (35 %). Fifty-four (17 %) patients experienced side effects of grade 3 (15 %) or grade 4 (2 %), and two patients grade 5 toxicities. Bendamustine-based first-line treatment of patients with advanced indolent NHL and MCL in clinical routine practice was assessed as effective and well tolerated in our study. Response was comparable to results from interventional clinical trials.

How I treat Waldenström macroglobulinemia.

Waldenström macroglobulinemia (WM) is a B-cell neoplasm manifested by the accumulation of clonal immunoglobulin (Ig)M-secreting lymphoplasmacytic cells. MYD88 and CXCR4 warts, hypogammaglobulinemia, infections, myelokathexis syndrome-like somatic mutations are present in >90% and 30% to 35% of WM patients, respectively, and impact disease presentation, treatment outcome, and overall survival. Familial predisposition is common in WM. Asymptomatic patients should be observed. Patients with disease-related hemoglobin <10 g/L, platelets <100 × 10(9)/L, bulky adenopathy and/or organomegaly, symptomatic hyperviscosity, peripheral neuropathy, amyloidosis, cryoglobulinemia, cold-agglutinin disease, or transformed disease should be considered for therapy. Plasmapheresis should be used for patients with symptomatic hyperviscosity and before rituximab for those with high serum IgM levels to preempt a symptomatic IgM flare. Treatment choice should take into account specific goals of therapy, necessity for rapid disease control, risk of treatment-related neuropathy, immunosuppression and secondary malignancies, and planning for future autologous stem cell transplantation. Frontline treatments include rituximab alone or rituximab combined with alkylators (bendamustine and cyclophosphamide), proteasome inhibitors (bortezomib and carfilzomib), nucleoside analogs (fludarabine and cladribine), and ibrutinib. In the salvage setting, an alternative frontline regimen, ibrutinib, everolimus, or stem cell transplantation can be considered. Investigational therapies under development for WM include agents that target MYD88, CXCR4, BCL2, and CD27/CD70 signaling, novel proteasome inhibitors, and chimeric antigen receptor-modified T-cell therapy.

Effect of bendamustine in combination with rituximab on QT interval duration in patients with advanced de novo indolent non-Hodgkin or mantle cell lymphoma.

PURPOSE: Bendamustine is used in chronic lymphocytic leukemia (first-line) and indolent B-cell non-Hodgkin lymphoma (NHL) that progressed during/within 6 months of treatment with rituximab or a rituximab-containing regimen. This study was a postapproval commitment to investigate bendamustine's effect on cardiac repolarization in treatment-naïve adults with advanced indolent NHL/mantle cell lymphoma (MCL). METHODS: In this multicenter, open-label, phase 3 study, patients received 6-8 28-day cycles of bendamustine (90 mg/m(2), days 1 and 2) and rituximab (375 mg/m(2), day 1). Exclusions included a history of cardiac conditions with potential for QT prolongation. The primary endpoint was change in Fridericia-corrected QT (QTcF; 3 electrocardiograms per time point) on day 2 of cycle 1, from just before infusion to end of infusion (immediately postinfusion, coinciding with maximum plasma concentration of bendamustine). Change 1 h postinfusion was also measured. Exploratory assessments included specific QTcF outlier analyses (new QTcF >500 ms, change >60 ms) and morphological changes. RESULTS: Of the 54 enrolled patients (mean age, 62.9 years), 53 received ≥1 dose; 49 completed ≥6 cycles. Mean QTcF change from baseline was 6.7 ms at end of infusion; no mean changes >20 ms were detected ≤1 h postinfusion. No patients met specific outlier criteria at end of infusion or 1 h postinfusion. No morphological changes were detected. CONCLUSIONS: In this small treatment-naïve population with advanced NHL/MCL, bendamustine did not produce a clinically relevant increase in mean QTcF on the second infusion day. The potential for delayed effects on QT interval after 1 h was not evaluated.

Bendamustine, thalidomide and dexamethasone combination therapy for relapsed/refractory myeloma patients: results of the MUKone randomized dose selection trial.

There is a significant unmet need in effective therapy for relapsed myeloma patients once they become refractory to bortezomib and lenalidomide. While data from the front line setting suggest bendamustine is superior to melphalan, there is no information defining optimal bendamustine dose in multiply-treated patients. We report a multi-centre randomized two-stage phase 2 trial simultaneously assessing deliverability and activity of two doses of bendamustine (60 mg/m2 vs. 100 mg/m2) days 1 and 8, thalidomide (100 mg) days 1-21 and low dose dexamethasone (20 mg) days 1, 8, 15 and 22 of a 28-d cycle. Ninety-four relapsing patients were treated on trial, with a median three prior treatment lines. A pre-planned interim deliverability and activity assessment led to closure of the 100 mg/m2 arm due to excess cytopenias, and led to amendment of entry criteria for cytopenias. Non-haematological toxicities including thromboembolism and neurotoxicity were infrequent. In the 60 mg/m2 arm, treatment was deliverable in 61.1% subjects and the partial response rate was 46.3% in the study eligible population, with 7.5 months progression-free survival. This study demonstrates bendamustine at 60 mg/m2 twice per month with thalidomide and dexamethasone is deliverable for repeated cycles in heavily pre-treated myeloma patients and has substantial clinical activity.

Obinutuzumab plus fludarabine/cyclophosphamide or bendamustine in the initial therapy of CLL patients: the phase 1b GALTON trial.

Obinutuzumab is a type 2, glycoengineered, anti-CD20 antibody recently approved with chlorambucil for the initial therapy of chronic lymphocytic leukemia (CLL). In this nonrandomized, parallel-cohort, phase 1b, multicenter study, we explored the safety and preliminary efficacy of obinutuzumab-bendamustine (G-B) or obinutuzumab fludarabine cyclophosphamide (G-FC) for the therapy of previously untreated fit patients with CLL. Patients received up to 6 cycles of G-B (n = 20) or G-FC (n = 21). The primary end point was safety, with infusion-related reactions (88%, grade 3-4 20%) being the most common adverse event and grade 3-4 neutropenia in 55% on G-B and 48% on G-FC. Mean cycles completed were 5.7 for G-B and 5.1 for G-FC, with 2 and 7 early discontinuations, respectively. The objective response rate (ORR) for G-B was 90% (18/20) with 20% complete response (CR) and 25% CR with incomplete marrow recovery (CRi). The ORR for G-FC was 62% (13/21), with 10% CR and 14% CRi, including 4 patients not evaluable. With a median follow-up of 23.5 months in the G-B cohort and 20.7 months in the G-FC cohort, no patient has relapsed or died. We conclude that obinutuzumab with either B or FC shows manageable toxicity and has promising activity. This study was registered at www.clinicaltrials.gov as #NCT01300247.

Safety and efficacy of Temsirolimus in combination with Bendamustine and Rituximab in relapsed mantle cell and follicular lymphoma.

In this phase I/II study, we explored the combination of Temsirolimus with Bendamustine and Rituximab (BeRT) in patients with r/r follicular lymphoma (FL) or mantle cell lymphoma (MCL). Patients with 1-3 prior therapies received Bendamustine (90 mg/m(2), day 1+2) and Rituximab (375 mg/m(2), day 1) with Temsirolimus in doses from 25 to 75 mg added on day 1, 8, 15 of a 28-day cycle. Fifteen (11 MCL, 4 FL) patients were included in the phase I. Median age was 73 years and median pretreatment number was 2. No formal dose-limiting toxicity was observed. Dominant non-hematological side effects were fatigue in 11 (73%), nausea in 9 (60%), mucositis in 7 (47%) and vomiting in 6 patients (40%). Cough, diarrhea, pyrexia and rash were observed in five patients (33%) each. Grade 3/4 events included leukopenia in 6 (40%), neutropenia in 4 (27%) and thrombocytopenia in 2 patients (13%). An objective response was observed in 14/15 patients (93%), including 5 complete response (33%; all MCL). After a median follow-up of 19 months, 67% of patients are without signs of progression. Temsirolimus can be safely added to BR with promising preliminary activity. Recruitment in phase II is ongoing.

[Alleviated anemia by bendamustine in cold agglutinin disease associated with small lymphocytic lymphoma].

A 77-year-old man was diagnosed with cold agglutinin disease in 2004. He had been treated with prednisolone with stabilization of hemoglobin in the 6- to 8-g/dl range. However, his hemolytic anemia worsened, and computed tomography showed systemic lymphadenopathy in May 2012. A pathological diagnosis of small lymphocytic lymphoma was made based on an inguinal lymph node biopsy. Treatment was started with rituximab. However, there was no response to 6 doses of rituximab monotherapy. He next received 6 courses of bendamustine in combination with rituximab. This resulted in stabilization of hemoglobin and independence from transfusion support. To the best of our knowledge, this is only the second case report describing bendamustine plus rituximab treatment for non-Hodgkin lymphoma complicated by cold agglutinin disease. Our results in this case suggest bendamustine to potentially be a useful therapeutic option in patients with cold agglutinin disease.

A phase I study of bendamustine, lenalidomide and rituximab in relapsed and refractory lymphomas.

Many patients with non-Hodgkin (NHL) or Hodgkin lymphoma (HL) relapse or are refractory to initial therapy and require additional options. Bendamustine (B), lenalidomide (L) and rituximab (R) each have activity in this setting. This study was performed to determine the safety of BLR and its optimal phase II dose. Patients with NHL or HL failing standard therapies received B (90 mg/m(2)  days 1, 2 every 28 days), and L (escalating from 5 mg 21/28 days) for six cycles, followed by 6 months of L. At the highest dose R 375 mg/m(2) on day one of each cycle was added for patients with B-NHL. Histologies included diffuse large B-cell lymphoma (DLBCL, 11), marginal zone lymphoma (3), HL (2), and one each of transformed follicular lymphoma, Sézary syndrome, Waldenström macroglobulinaemia and mantle cell lymphoma. Neutropenia was the most common grade 3 and 4 toxicity, but no maximum tolerated dose was identified. Of 20 patients, seven responded (35%), including four complete remissions, with five unmaintained responses from 28+ to 37+ months, including 2 DLBCL. BR with 20 mg l at, 21/28 days achieved durable responses; however, in light of its modest activity, and the availability of newer targeted therapies, the future of BLR is uncertain.

A unique description of stage IV extranodal marginal zone lymphoma (EMZL) in an adolescent associated with gamma heavy chain disease.

Extranodal Marginal zone lymphoma (EMZL) is a rare, usually localized disease in children. Advanced stage EMZL in adults is considered incurable, with prolonged remissions after chemotherapy. Gamma heavy chain disease (γHCD) is a rare disease of adults associated with lympho-proliferative processes with no comparable reports in children. A case of stage-IV EMZL with γHCD in an adolescent is discussed including treatment with Bendamustine plus Rituximab. The patient remains disease free 18 months from diagnosis. This case highlights necessity for careful diagnostic work-up to identify indolent lymphomas in children which may respond to less toxic chemotherapy than used for common pediatric lymphomas.

Phase I/II study of the hypoxia-activated prodrug PR104 in refractory/relapsed acute myeloid leukemia and acute lymphoblastic leukemia.

We previously demonstrated vast expansion of hypoxic areas in the leukemic microenvironment and provided a rationale for using hypoxia-activated prodrugs. PR104 is a phosphate ester that is rapidly hydrolyzed in vivo to the corresponding alcohol PR-104A and further reduced to the amine and hydroxyl-amine nitrogen mustards that induce DNA cross-linking in hypoxic cells under low oxygen concentrations. In this phase I/II study, patients with relapsed/refractory acute myeloid leukemia (n=40) after 1 or 2 prior treatments or acute lymphoblastic leukemia (n=10) after any number of prior treatments received PR104; dose ranged from 1.1 to 4 g/m(2). The most common treatment-related grade 3/4 adverse events were myelosuppression (anemia 62%, neutropenia 50%, thrombocytopenia 46%), febrile neutropenia (40%), infection (24%), and enterocolitis (14%). Ten of 31 patients with acute myeloid leukemia (32%) and 2 of 10 patients with acute lymphoblastic leukemia (20%) who received 3 g/m(2) or 4 g/m(2) had a response (complete response, n=1; complete response without platelet recovery, n=5; morphological leukemia-free state, n=6). The extent of hypoxia was evaluated by the hypoxia tracer pimonidazole administered prior to a bone marrow biopsy and by immunohistochemical assessments of hypoxia-inducible factor alpha and carbonic anhydrase IX. A high fraction of leukemic cells expressed these markers, and PR104 administration resulted in measurable decrease of the proportions of hypoxic cells. These findings indicate that hypoxia is a prevalent feature of the leukemic microenvironment and that targeting hypoxia with hypoxia-activated prodrugs warrants further evaluation in acute leukemia. The trial is registered at clinicaltrials.gov identifier: 01037556.

Results of a phase II study of bendamustine and ofatumumab in untreated indolent B cell non-Hodgkin's lymphoma.

The efficacy/tolerability of bendamustine, a unique alkylator, plus ofatumumab, a human anti-CD20 monoclonal antibody, was evaluated for previously untreated indolent B cell non-Hodgkin's lymphoma (NHL). The study investigated whether the overall response rate (ORR) for bendamustine-ofatumumab was similar to historical bendamustine-rituximab ORRs (≥90 %). In this multicenter, open-label, single-arm, phase II study, patients received six planned 28-day cycles of bendamustine (90 mg/m(2) on days 1 and 2 of each cycle) and ofatumumab (300 mg on day 1, 1000 mg on day 8 of cycle 1, and on day 1 of subsequent cycles). The primary outcome was ORR. Secondary objectives included safety and tolerability. Exploratory evaluations included percentage of patients with positive baseline [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) scans who converted to negative postbaseline and quality of life (QOL) scores. The treated/safety analysis population received ≥1 dose of either therapy. The bendamustine-ofatumumab ORR was 90 % (95 % confidence interval, 77.8-96.6) in 49 treated patients (67 % complete response, 22 % partial response). No patients had progressive disease. Bendamustine-ofatumumab was acceptably tolerated. All 49 patients had ≥1 adverse event, the most common being nausea (61 %), fatigue (55 %), and infusion-related reactions (45 %, all but 1 occurring during cycle 1). The proportion of patients whose FDG-PET scans converted to negative postbaseline was 88 %. Changes in QOL scores were minor. In patients with treatment-naive, indolent B cell NHL, bendamustine-ofatumumab exhibited a high degree of activity (90 % ORR), comparable with historical bendamustine-rituximab ORRs (≥90 %), and was adequately tolerated ( ClinicalTrials.gov identifier: NCT01108341).

Rare presentation of secondary cutaneous involvement by splenic marginal zone lymphoma: report of a case and review of the literature.

Cutaneous lymphomas encompass a broad spectrum of malignancies, including both primary and secondary cutaneous lymphomas. Determining the exact subtype of cutaneous lymphoma offers prognostic importance and directs therapeutic decisions. We describe the case of a 67-year-old woman with cutaneous involvement of splenic marginal zone lymphoma successfully treated with rituximab and bendamustine. We discuss the diagnostic work-up, including the histopathologic findings and treatment of this disease.

Bendamustine in combination with thalidomide and dexamethasone is a viable salvage option in myeloma relapsed and/or refractory to bortezomib and lenalidomide.

Treatment options are limited in myeloma relapsed or refractory to both bortezomib and lenalidomide (double-relapsed/refractory multiple myeloma; DRMM). Bendamustine is an antitumour agent that has efficacy in relapsed myeloma. We retrospectively analysed data from 30 DRMM patients who received a combination of bendamustine, thalidomide and dexamethasone (BTD) in 28-day treatment cycles. Bendamustine was administered with a cumulative dose of up to 200 mg/m(2). Thalidomide (50-150 mg) was given daily as tolerated, and dexamethasone was given at an equivalent dose of up to 160 mg per cycle. A median of 5 (2-9) treatment cycles were administered per patient. Twenty-six patients (87 %) achieved stable disease or better. At a median follow-up time of 12.1 (2.3-21.5) months, median (95 % CI) progression-free survival and overall survival were 4.0 (2.6-5.3) months and 7.2 (5.2-9.2) months, respectively. The most common grade 3-4 adverse events were haematological: anaemia (n = 8, 34.8 %), neutropenia (n = 16, 69.6 %) and thrombocytopenia (n = 10, 43.5 %). Non-haematological toxicities included pain (n = 3, 13.0 %), infection (n = 7, 30.4 %) and sensory neuropathy (n = 1, 4.3 %). We propose that BTD is a viable salvage treatment option for DRMM patients.