The Non-Hodgkin Lymphoma Treatment and Side Effects: A Systematic Review and Meta-Analysis

OBJECTIVE

This paper aims to review studies regarding side effects found during Non-Hodgkin Lymphoma treatment, to suggest the drug class most associated with these effects, as well as the most prevalent side effect grade.

METHODS

This review is registered in PROSPERO (IDCRD42022295774) and followed the PICOS strategy and PRISMA guidelines. The search was carried out in the databases PubMed/MEDLINE, Scientific Electronic Library Online, and DOAJ. Medical Subject Headings Terms were used and quantitative studies with conclusive results regarding side effects during the non-Hodgkin lymphoma treatment were selected. Patent information was obtained from google patents.

RESULTS

Monoclonal antibodies were the main drug class associated with side effects during NHL therapy. The combination of Rituximab (Rituxan®; patent EP1616572B) and iInotuzumab (Besponsa®; patent EP1504035B3) was associated with a higher incidence of thrombocytopenia (p<0.05), while the combination of Rituximab and Venetoclax (Venclexta®; patent CN107089981A) was associated with a higher incidence of neutropenia (p<0.05) when compared to Bendamustine combinations (Treanda ™; patent US20130253025A1). Meta-analysis revealed a high prevalence of grade 3-4 neutropenia and thrombocytopenia in men. Finally, Americans and Canadians experienced a higher prevalence of these side effects, when compared to others nationalities (p<0.05).

CONCLUSION

Patents regarding the use of monoclonal antibodies in NHL treatment were published in the last year. Monoclonal antibodies associated with neutropenia (grade 3-4) and thrombocytopenia, especially in North American men treated for NHL, and with an average age of 62 years demonstrated importance in this study.

Pixantrone Sensitizes Gram-Negative Pathogens to Rifampin

The emergence of bacterial drug resistance poses a severe threat to global public health. In particular, antimicrobial-resistant pathogens lead to a high rate of treatment failure and significantly increase mortality. Repurposing FDA-approved compounds to sensitize superbugs to conventional antibiotics provides a promising strategy to alleviate such crises. Pixantrone (PIX) has been approved for treating aggressive B-cell non-Hodgkin's lymphoma. By high-throughput drug screening, we profiled the synergistic activity between PIX and rifampin (RFP) against Gram-negative extensively drug-resistant isolates by checkerboard assay. Mechanistic studies demonstrated that PIX impacted the flagellum assembly, induced irreversible intracellular reactive oxygen species accumulation and disrupted proton motive force. In addition, the combination of PIX with RFP possesses effective antimicrobial activity against multidrug-resistant strains in vivo without detected toxicity. Collectively, these results reveal the potential of PIX in combination with RFP as a therapy option for refractory infections caused by Gram-negative pathogens. IMPORTANCE Bacterial resistance has become increasingly serious because of the widespread use and abuse of antibiotics. In particular, the emergence of multidrug-resistant bacteria has posed a serious threat to human public health. Drug repurposing, the process of finding new uses for existing drugs, provide a promising pathway to solve antimicrobial resistance. Compared to the development of novel antibiotics, this strategy leverages well-characterized pharmacology and toxicology of known drugs and is more cost-effective.

Randomized Phase II Study of Two Doses of Pixantrone in Patients with Metastatic Breast Cancer (NCCTG N1031, Alliance)

BACKGROUND

Anthracycline use in metastatic breast cancer (MBC) is hindered by cumulative exposure limits and risk of cardiotoxicity. Pixantrone, a novel aza-anthracenedione with structural similarities to mitoxantrone and anthracyclines, is theorized to exhibit less cardiotoxicity, mainly due to lack of iron binding. We conducted a randomized phase II study to evaluate the efficacy and safety of 2 dosing schedules of pixantrone in patients with refractory HER2-negative MBC.

METHODS

Intravenous pixantrone was administered at 180 mg/m2 every 3 weeks (group A) versus 85 mg/m2 on days 1, 8, and 15 of a 28-day cycle (group B). Primary endpoint was objective response rate (ORR) and secondary endpoints included progression-free survival (PFS), median 6-month PFS, overall survival (OS), safety, quality of life, and serial assessment of circulating tumor cells. A 20% ORR was targeted as sufficient for further testing of pixantrone in this patient population.

RESULTS

Forty-five patients were evaluable, with 2 confirmed partial responses in group A and 1 in group B. The trial was terminated due to insufficient activity. Overall median PFS and OS were 2.8 (95% confidence interval [CI]: 2.0-4.1) and 16.8 (95% CI: 8.9-21.6) months, respectively. Notable overall grade 3-4 adverse events were the following: neutrophil count decrease (62%), fatigue (16%), and decrease in ejection fraction (EF) (4%).

CONCLUSION

Pixantrone has insufficient activity in the second- and third-line MBC setting. It appears, however, to have limited cardiotoxicity. (ClinicalTrials.gov ID: NCT01086605).

Current Opinion on Pixantrone in the Treatment of Non-Hodgkin B-Cell Lymphoma

Not many treatment options exist for patients with relapsed or refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) in whom first- and second-line therapies were unsuccessful. This is especially true for patients with aggressive lymphomas. The innovative agent pixantrone has shown some promising results in terms of disease-free and overall survival, both in monotherapy as well as in combinations. However, recent trials (Phase III and real-world studies) reported unsatisfactory results, thereby raising the question about the role of pixantrone in the current treatment of R/R aggressive lymphomas. Nonetheless, there might still be a potential position for this drug in combinations, for use as first-line treatment of patients with cardiac dysfunction. This article summarizes the definition, structure, mechanism of action and reduced cardiotoxicity of pixantrone as well as efficacy and toxicity both in monotherapy and in combinations, as treatment for aggressive and indolent non-Hodgkin lymphomas.

Role of Oxidative Stress in the Mechanisms of Anthracycline-Induced Cardiotoxicity: Effects of Preventive Strategies

Anthracycline-induced cardiotoxicity (AIC) persists as a significant cause of morbidity and mortality in cancer survivors. Although many protective strategies have been evaluated, cardiotoxicity remains an ongoing threat. The mechanisms of AIC remain unclear; however, several pathways have been proposed, suggesting a multifactorial origin. When the central role of topoisomerase 2β in the pathophysiology of AIC was described some years ago, the classical reactive oxygen species (ROS) hypothesis shifted to a secondary position. However, new insights have reemphasized the importance of the role of oxidative stress-mediated signaling as a common pathway and a critical modulator of the different mechanisms involved in AIC. A better understanding of the mechanisms of cardiotoxicity is crucial for the development of treatment strategies. It has been suggested that the available therapeutic interventions for AIC could act on the modulation of oxidative balance, leading to a reduction in oxidative stress injury. These indirect antioxidant effects make them an option for the primary prevention of AIC. In this review, our objective is to provide an update of the accumulated knowledge on the role of oxidative stress in AIC and the modulation of the redox balance by potential preventive strategies.

RETRACTED: Design, synthesis, and biological evaluation of heterotetracyclic quinolinone derivatives as anticancer agents targeting topoisomerases

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the authors. The authors regret to inform that they would like to withdraw this accepted article, due to serious errors in authorship, affiliations, material sources and supporting grant names/numbers. The authors sincerely apologize for these oversights and miscommunications the study caused.

Efficacy and safety of pixantrone for the treatment of multiply relapsed or refractory aggressive non-Hodgkin B-cell lymphomas

BACKGROUND AND OBJECTIVE

Few treatment options exist for patients with relapsed/refractory (R/R) B-cell non-Hodgkin lymphoma (NHL) who fail first- and second-line therapies. Pixantrone is a novel aza-anthracenedione agent with reduced potential for cardiotoxicity but maintained anti-tumour activity relative to anthracyclines. The current retrospective, observational, real-life study was undertaken in 79 patients who received pixantrone monotherapy for multiply R/R aggressive B-cell NHL in Spain and Italy.

RESULTS

Before pixantrone, patients had received a median of 3 prior therapies and 84.6% of them were refractory to the last regimen. Median progression-free survival (mPFS) was 2.8 months (95% confidence interval [CI] 2.1-3.6) and median overall survival (mOS) was 4.0 months (95%CI 5.6-7.9), with an objective response rate (ORR) of 29% (complete remission [CR]: 13.2%, partial remission [PR]: 15.2%). Patients receiving ≥2 cycles of pixantrone showed mPFS and mOS of 3.1 and 6.0 months, respectively, and an ORR of 36.8% (CR: 17.5%, PR: 19.3%). Overall, 63.3% of patients reported ≥1 adverse event (AE), most commonly haematological AEs. One patient developed grade 2 sinus tachycardia.

CONCLUSION

Pixantrone was effective and well tolerated in a real-world population of multiply R/R patients with aggressive B-cell NHL, many of whom had very poor prognostic factors.

Pixantrone demonstrates significant in vitro activity against multiple myeloma and plasma cell leukemia

Treatment results for multiple myeloma and plasma cell leukemia have considerably improved, but cure remains elusive and establishing new therapeutic approaches constitutes a major unmet clinical need. We analyzed the anti-myeloma properties of the aza-anthracenedione pixantrone which has been successfully used in a phase III study for the treatment of patients with aggressive non-Hodgkin's lymphoma as monotherapy as well as in combination regimes in vitro and in an adapted in vivo model (ex ovo chicken chorioallantoic membrane (CAM) assay). Pixantrone significantly inhibited proliferation and metabolic activity of all investigated myeloma cell lines. Importantly, anti-myeloma effects were more pronounced in tumor cell lines than in stromal cells, mesenchymal stem cells, and peripheral blood mononuclear cells of healthy controls. Apoptosis of myeloma cell lines was observed only after a 7-day incubation period, indicating a fast cytostatic and a slower cytotoxic effect of this drug. Pixantrone reduced the viability of primary plasma cells of patients and induced downregulation of myeloma-cell growth in the CAM assay. Additionally, we demonstrate in vitro synergism between pixantrone and the histone deacetylase inhibitor panobinostat with respect to its anti-proliferative features. From these data, we conclude that systematic investigations of the clinical usefulness of pixantrone in the framework of controlled clinical trials are clearly indicated (e.g., in penta-refractory patients).

An evaluation of pixantrone for the treatment of non-Hodgkin's lymphoma

INTRODUCTION

The overall prognosis for patients with relapsed or refractory aggressive non-Hodgkin's lymphomas is poor. Only a minority of patients are able to receive autologous stem cell transplantation. Patients not transplant-eligible or patients relapsing after transplantation have an urgent need for effective treatment options. Pixantrone is the only compound approved in Europe for this situation. Areas covered: This review describes the clinical development of pixantrone, starting with phase I trials up to phase III trials in order to define the role of pixantrone in treatment algorithms. The effectiveness of pixantrone is considered in relation to alternative therapeutic options. Furthermore, the similarities and differences between pixantrone and anthracyclines is highlighted, with a special focus on the mode of action and on cardiotoxicity. Expert opinion: Pixantrone is a valuable treatment option in relapsed and refractory aggressive lymphomas, with documented disease responses, manageable toxicities and clear distinctions to anthracyclines. Additional studies are needed to evaluate the role of pixantrone in combination with other compounds, especially with upcoming targeted therapies, and to confirm the effectiveness of pixantrone in other lymphoma subtypes, e.g. follicular lymphomas.

Recent developments in topoisomerase-targeted cancer chemotherapy

The DNA topoisomerase enzymes are essential to cell function and are found ubiquitously in all domains of life. The various topoisomerase enzymes perform a wide range of functions related to the maintenance of DNA topology during DNA replication, and transcription are the targets of a wide range of antimicrobial and cancer chemotherapeutic agents. Natural product-derived agents, such as the camptothecin, anthracycline, and podophyllotoxin drugs, have seen broad use in the treatment of many types of cancer. Selective targeting of the topoisomerase enzymes for cancer treatment continues to be a highly active area of basic and clinical research. The focus of this review will be to summarize the current state of the art with respect to clinically used topoisomerase inhibitors for targeted cancer treatment and to discuss the pharmacology and chemistry of promising new topoisomerase inhibitors in clinical and pre-clinical development.

Long-Term Response and Remission with Pixantrone in Patients with Relapsed or Refractory Aggressive Non-Hodgkin Lymphoma: Post-Hoc Analysis of the Multicenter, Open-Label, Randomized PIX301 Trial

Background

Pixantrone is recommended in relapsed and refractory non-Hodgkin lymphoma (NHL) or heavily pretreated NHL patients. Its conditional approval in Europe was based on results from the open-label, randomized, phase 3 PIX301 study, comparing pixantrone monotherapy with physician’s choice of treatment in 140 patients with relapsed or refractory aggressive NHL.

Methods

This post-hoc analysis of the PIX301 study investigated possible correlations between patient characteristics and clinical response in 17 patients (24%) treated with pixantrone who achieved a complete response (CR) or an unconfirmed complete response (CRu) at study end.

Results

These patients (10 male and 7 female) had a median age of 61 (range 41–75) years, and the most common diagnoses were diffuse large B-cell lymphoma (n = 10) and transformed indolent lymphoma (n = 4). Most had received two prior lines of therapy (n = 12). There was wide variation in the time from diagnosis to study entry (219–4777 days). Among the 17 patients who achieved a CR/CRu with pixantrone, 6 had stable or progressive disease as a response to their last regimen, 7 had a partial response, and 4 had a CR/CRu. Four patients from the pixantrone group survived without progression for more than 400 days. Prior response to previous therapies did not appear to affect long-term response to pixantrone.

Conclusions

These observations suggest that pixantrone monotherapy in patients with multiply relapsed or refractory aggressive NHL who had received at least two prior therapies can be associated with durable responses and long-term remission, and this may be unrelated to the clinical response to the last therapy.

Pixantrone, a new anticancer drug with the same old cardiac problems? An in vitro study with differentiated and non-differentiated H9c2 cells

Pixantrone (PIX) is an anticancer drug approved for the treatment of multiple relapsed or refractory aggressive B-cell non-Hodgkin's lymphoma. It is an aza-anthracenedione synthesized to have the same anticancer activity as its predecessors, anthracyclines (e.g. doxorubicin) and anthracenediones (e.g. mitoxantrone), with lower cardiotoxicity. However, published data regarding its possible cardiotoxicity are scarce. Therefore, this work aimed to assess the potential cytotoxicity of PIX, at clinically relevant concentrations (0.1; 1; and 10 μM) in both non-differentiated and 7-day differentiated H9c2 cells. Cells were exposed to PIX for 48 h and cytotoxicity was evaluated through phase contrast microscopy, Hoescht staining and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction and neutral red (NR) uptake assays. Cytotoxicity was observed in differentiated and non-differentiated H9c2 cells, with detached cells and round cells evidenced by phase contrast microscopy, mainly at the highest concentration tested (10 μM). In the Hoechst staining, PIX 10 μM showed a marked decrease in the number of cells when compared to control but with no signs of nuclear condensation. Furthermore, significant concentration-dependent mitochondrial dysfunction was observed through the MTT reduction assay. The NR assay showed similar results to those obtained in the MTT reduction assay in both differentiated and non-differentiated H9c2 cells. The differentiation state of the cells was not crucial to PIX effects, although PIX toxicity was slightly higher in differentiated H9c2 cells. To the best of our knowledge, this was the first in vitro study performed with PIX in H9c2 cells and it discloses worrying cytotoxicity at clinically relevant concentrations.

Chemotherapeutic Drugs and Mitochondrial Dysfunction: Focus on Doxorubicin, Trastuzumab, and Sunitinib

Many cancer therapies produce toxic side effects whose molecular mechanisms await full elucidation. The most feared and studied side effect of chemotherapeutic drugs is cardiotoxicity. Also, skeletal muscle physiology impairment has been recorded after many chemotherapeutical treatments. However, only doxorubicin has been extensively studied for its side effects on skeletal muscle. Chemotherapeutic-induced adverse side effects are, in many cases, mediated by mitochondrial damage. In particular, trastuzumab and sunitinib toxicity is mainly associated with mitochondria impairment and is mostly reversible. Vice versa, doxorubicin-induced toxicity not only includes mitochondria damage but can also lead to a more robust and extensive cell injury which is often irreversible and lethal. Drugs interfering with mitochondrial functionality determine the depletion of ATP reservoirs and lead to subsequent reversible contractile dysfunction. Mitochondrial damage includes the impairment of the respiratory chain and the loss of mitochondrial membrane potential with subsequent disruption of cellular energetic. In a context of increased stress, AMPK has a key role in maintaining energy homeostasis, and inhibition of the AMPK pathway is one of the proposed mechanisms possibly mediating mitochondrial toxicity due to chemotherapeutics. Therapies targeting and protecting cell metabolism and energy management might be useful tools in protecting muscular tissues against the toxicity induced by chemotherapeutic drugs.

Management of Multiply Relapsed Aggressive Non-Hodgkin Lymphoma: New Perspectives

Patients with refractory/relapsed (R/R) non-Hodgkin lymphoma (NHL) make up a very heterogeneous population with a poor life expectancy. The objective of this symposium was to provide an overview of the current treatment landscape for aggressive NHL, as well as the future research on new treatments. Transplant-eligible patients receive salvage chemotherapy, followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT). Patients who fail transplant or are transplant-ineligible generally receive palliative treatment or enter clinical trials; there is no standard of care and thus there is a high unmet clinical need. Pixantrone is currently indicated for adult patients with multiply R/R aggressive B-cell NHL, thereby filling the unmet clinical need in this field. The symposium started with a brief overview of the meeting objectives. This was followed by an overview of the current and future treatment landscape for aggressive NHL, including a case study of a patient with diffuse large B-cell lymphoma (DLBCL) with multiple relapses receiving pixantrone as monotherapy. The results and post hoc analysis of the CORAL and the SCHOLAR1 studies were reviewed, including the relative merits of combination therapy versus monotherapy for patients with relapsed DLBCL who had failed second-line salvage therapy. The symposium ended with an outline of the profile and mechanism of action of pixantrone, and evidence from the PIX301 study that provided the basis for regulatory approval for the use of pixantrone in third and fourth-line treatment of R/R aggressive B-cell NHL. The clinical efficacy and safety of pixantrone were reviewed, together with a future perspective on the ongoing PIX306 trial. The symposium concluded with the presentation of two clinical cases of patients treated with pixantrone, a ‘Question and Answer’ session, and a panel discussion.

Time course of changes in oxidative stress and stress-induced proteins in cardiomyocytes exposed to doxorubicin and prevention by vitamin C

We previously reported that Vitamin C (Vit C) protects against doxorubicin (Dox)-induced cardiotoxicity by reducing oxidative stress, p38 mitogen-activated kinase (MAPK) and p53 activation and rescuing cell death in isolated adult cardiomyocytes. The pattern of activation and the role of oxidative stress as well as down-stream mechanisms for such protection remain elusive. Therefore the present study aims to analyze time-dependant generation of reactive oxygen species (ROS) and the activation of stress induced signalling pathways in cardiomyocytes treated with Dox and Vit C. The data provides further understanding of heart pathophysiology in response to Dox at the cellular level, and may help to optimize the timing of various therapeutic approaches. Cardiomyocytes isolated from adult Sprague-Dawley rats were exposed to Dox (10 μM), Vit C (25 μM), and Dox + Vit C for different time intervals up to 24 h. p38-JNK (SB203580) and p53 (pifithrin-α) inhibitors were used to determine the role of each respective signalling protein. Dox administration to cardiomyocytes increased the levels of ROS in a time-dependent manner that followed the activation of stress-induced proteins p53, p38 and JNK MAPKs, culminating in an increase in autophagy and apoptosis markers. Dox-induced increase in ROS was alleviated by Vit C adjuvant treatment at all time-points and this was also correlated with blunting of the activation of the studied signaling pathways leading to the prevention of apoptosis and preservation of cell viability. Protective effect of Vit C against the activation of stress induced proteins, autophagy and apoptosis was mainly attributed to its antioxidant properties even though blockage of p38, JNK and p53 by pharmacological inhibitors also suppressed Dox-induced apoptosis. ROS is defined as a key inducer of cardiomyocyte damage under Dox exposure; Vit C could effectively counteract all Dox-induced changes in cardiomyocytes and may potentially be used as an antioxidant adjuvant therapy to protect against Dox-induced cardiomyopathy.

The Servier oncology pipeline in 2017

Cancer is a complex, multifactorial disease that for years has been the focus of intensive research efforts to explore both the molecular and biological mechanisms involved and the development of novel agents to target these pathways. Servier is an independent French pharmaceutical company with a focus on oncology. Currently, Servier's commercial portfolio includes agents used to treat non-Hodgkin's lymphoma and metastatic colorectal cancer; Servier's oncology pipeline involves agents for the treatment of both solid and hematological tumors. The main areas of future research focus on the development of therapeutics targeting apoptosis or the active immune components involved in tumour development/maintenance. Servier intends to continue its focus on cutting-edge oncology innovation by collaborating with both industry and academia, and maintaining its strong patient-centered approach.

Pixantrone: A Review in Relapsed or Refractory Aggressive Non-Hodgkin's Lymphoma

Pixantrone (Pixuvri^®) is an aza-anthracenedione with a novel mode of action that is conditionally approved in the EU for use as monotherapy in adult patients with multiply relapsed or refractory aggressive B-cell non-Hodgkin's lymphoma (NHL). In the randomized, open-label, multinational, phase 3 PIX301 trial in patients with multiply relapsed or refractory aggressive NHL, the complete response (CR) plus unconfirmed CR (uCR) rate at the end of treatment (primary endpoint) was significantly higher with intravenous pixantrone monotherapy than with a single-agent comparator (vinorelbine, oxaliplatin, ifosfamide, etoposide, mitoxantrone or gemcitabine). Post hoc analysis also demonstrated a significantly higher CR/uCR rate in the subgroup of patients with centrally confirmed aggressive B-cell NHL who were receiving pixantrone versus a comparator agent as third- or fourth-line therapy. Pixantrone was generally well tolerated in PIX301, with a manageable adverse event profile. In conclusion, pixantrone is a useful option in patients with multiply relapsed or refractory aggressive B-cell NHL. Further results examining the use of pixantrone in combination with rituximab in patients previously treated with rituximab-containing regimens are awaited with interest.

Metabolic carbonyl reduction of anthracyclines - role in cardiotoxicity and cancer resistance. Reducing enzymes as putative targets for novel cardioprotective and chemosensitizing agents

Anthracycline antibiotics (ANT), such as doxorubicin or daunorubicin, are a class of anticancer drugs that are widely used in oncology. Although highly effective in cancer therapy, their usefulness is greatly limited by their cardiotoxicity. Possible mechanisms of ANT cardiotoxicity include their conversion to secondary alcohol metabolites (i.e. doxorubicinol, daunorubicinol) catalyzed by carbonyl reductases (CBR) and aldo-keto reductases (AKR). These metabolites are suspected to be more cardiotoxic than their parent compounds. Moreover, overexpression of ANT-reducing enzymes (CBR and AKR) are found in many ANT-resistant cancers. The secondary metabolites show decreased cytotoxic properties and are more susceptible to ABC-mediated efflux than their parent compounds; thus, metabolite formation is considered one of the mechanisms of cancer resistance. Inhibitors of CBR and AKR were found to reduce the cardiotoxicity of ANT and the resistance of cancer cells, and therefore are being investigated as prospective cardioprotective and chemosensitizing drug candidates. In this review, the significance of a two-electron reduction of ANT, including daunorubicin, epirubicin, idarubicin, valrubicin, amrubicin, aclarubicin, and especially doxorubicin, is described with respect to toxicity and efficacy of therapy. Additionally, CBR and AKR inhibitors, including monoHER, curcumin, (−)-epigallocatechin gallate, resveratrol, berberine or pixantrone, and their modulating effect on the activity of ANT is characterized and discussed as potential mechanism of action for novel therapeutics in cancer treatment.

Deep Learning to Predict the Formation of Quinone Species in Drug Metabolism

Many adverse drug reactions are thought to be caused by electrophilically reactive drug metabolites that conjugate to nucleophilic sites within DNA and proteins, causing cancer or toxic immune responses. Quinone species, including quinone-imines, quinone-methides, and imine-methides, are electrophilic Michael acceptors that are often highly reactive and comprise over 40% of all known reactive metabolites. Quinone metabolites are created by cytochromes P450 and peroxidases. For example, cytochromes P450 oxidize acetaminophen to N-acetyl-p-benzoquinone imine, which is electrophilically reactive and covalently binds to nucleophilic sites within proteins. This reactive quinone metabolite elicits a toxic immune response when acetaminophen exceeds a safe dose. Using a deep learning approach, this study reports the first published method for predicting quinone formation: the formation of a quinone species by metabolic oxidation. We model both one- and two-step quinone formation, enabling accurate quinone formation predictions in nonobvious cases. We predict atom pairs that form quinones with an AUC accuracy of 97.6%, and we identify molecules that form quinones with 88.2% AUC. By modeling the formation of quinones, one of the most common types of reactive metabolites, our method provides a rapid screening tool for a key drug toxicity risk. The XenoSite quinone formation model is available at http://swami.wustl.edu/xenosite/p/quinone .

Primary Prevention Strategies for Anthracycline Cardiotoxicity: A Brief Overview

The clinical use of doxorubicin and other antitumor anthracyclines is limited by a dose-related risk of cardiomyopathy and heart failure which may occur “on treatment” or any time, from months to years, after completing chemotherapy. Dose reductions diminish the incidence of cardiac events attributable to anthracyclines, but heart failure still occurs in some patients exposed to low or moderate anthracycline doses. Because anthracyclines improve the life expectancy of patients with, for example, breast cancer or lymphomas, preventing or diminishing the risk of early or delayed cardiotoxicity is of obvious clinical importance. Here, we briefly review some potential strategies of primary prevention that are based on what we know about the molecular mechanisms of cardiotoxicity, and what can be done, or might be done, to interfere with the pharmacokinetic, pharmacodynamic, and genetic determinants of cardiotoxicity.

Rethinking Drugs from Chemistry to Therapeutic Opportunities: Pixantrone beyond Anthracyclines

Pixantrone (6,9-bis[(2-aminoethyl)amino]benzo[g]isoquinoline-5,10-dione) has been approved by the European Medicines Agency for the treatment of refractory or relapsed non-Hodgkin's lymphoma (NHL). It is popularly referred to as a novel aza-anthracenedione, and as such it is grouped with anthracycline-like drugs. Preclinical development of pixantrone was in fact tailored to retain the same antitumor activity as that of anthracyclines or other anthracenediones while also avoiding cardiotoxicity that dose-limits clinical use of anthracycline-like drugs. Preliminary data in laboratory animals showed that pixantrone was active, primarily in hematologic malignancies, but caused significantly less cardiotoxicity than doxorubicin or mitoxantrone. Pixantrone was cardiac tolerable also in animals pretreated with doxorubicin, which anticipated a therapeutic niche for pixantrone to treat patients with a history of prior exposure to anthracyclines. This is the case for patients with refractory/relapsed NHL. Pixantrone clinical development, regulatory approval, and penetration in clinical practice were nonetheless laborious if not similar to a rocky road. Structural and nominal similarities with mitoxantrone and anthracyclines may have caused a negative influence, possibly leading to a general perception that pixantrone is a "me-too" anthracycline. Recent insights suggest this is not the case. Pixantrone shows pharmacological and toxicological mechanisms of action that are difficult to reconcile with anthracycline-like drugs. Pixantrone is a new drug with its own characteristics. For example, pixantrone causes mis-segregation of genomic material in cancer cells and inhibits formation of toxic anthracycline metabolites in cardiac cells. Understanding the differences between pixantrone and anthracyclines or mitoxantrone may help one to appreciate how it worked in the phase 3 study that led to its approval in Europe and how it might work in many more patients in everyday clinical practice, were it properly perceived as a drug with its own characteristics and therapeutic potential. The road is rocky but not a dead-end.

Pixantrone induces cell death through mitotic perturbations and subsequent aberrant cell divisions

Pixantrone is a novel aza-anthracenedione active against aggressive lymphoma and is being evaluated for use against various hematologic and solid tumors. The drug is an analog of mitoxantrone, but displays less cardiotoxicity than mitoxantrone or the more commonly used doxorubicin. Although pixantrone is purported to inhibit topoisomerase II activity and intercalate with DNA, exact mechanisms of how it induces cell death remain obscure. Here we evaluated the effect of pixantrone on a panel of solid tumor cell lines to understand its mechanism of cell killing. Initial experiments with pixantrone showed an apparent discrepancy between its anti-proliferative effects in MTS assays (short-term) compared with clonogenic assays (long-term). Using live cell videomicroscopy to track the fates of cells, we found that cells treated with pixantrone underwent multiple rounds of aberrant cell division before eventually dying after approximately 5 d post-treatment. Cells underwent abnormal mitosis in which chromosome segregation was impaired, generating chromatin bridges between cells or within cells containing micronuclei. While pixantrone-treated cells did not display γH2AX foci, a marker of DNA damage, in the main nuclei, such foci were often detected in the micronuclei. Using DNA content analysis, we found that pixantrone concentrations that induced cell death in a clonogenic assay did not impede cell cycle progression, further supporting the lack of canonical DNA damage signaling. These findings suggest pixantrone induces a latent type of DNA damage that impairs the fidelity of mitosis, without triggering DNA damage response or mitotic checkpoint activation, but is lethal after successive rounds of aberrant division.

Clinical approach to diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is the most common subtype of lymphoma. We now recognize that DLBCL corresponds to a biologically heterogeneous family of diseases. Given the potential for cure for most DLBCL patients, appropriate diagnostic and staging evaluation and therapy are essential. Here we review areas of consensus as well as controversy in the evaluation, treatment and monitoring of patients with DLBCL and its related subtypes.

Critical concepts, practice recommendations, and research perspectives of pixantrone therapy in non-Hodgkin lymphoma: a SIE, SIES, and GITMO consensus paper

OBJECTIVES

In this paper, we present a review of critical concepts and research perspectives and produce recommendations on the optimal use of pixantrone in non-Hodgkin lymphoma (NHL) by group discussion from an expert panel appointed by the Italian Society of Hematology and the affiliate societies, Società Italiana di Ematologia Sperimentale and Gruppo Italiano Trapianto di Midollo Osseo.

METHODS

Recommendations were produced using the Delphi process. Scientific evidence on pixantrone efficacy was analyzed using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology in the areas where at least one randomized trial was published. The following key issues were addressed for practical recommendations: pixantrone monotherapy in aggressive relapsed or refractory non-Hodgkin B-cell lymphomas and toxicity risk management in patients candidates to pixantrone.

RESULTS AND CONCLUSIONS

After a balanced and value-oriented discussion, the panel agreed that the benefit/risk profile was in favor of pixantrone in the treatment of adult patients with multiply relapsed or refractory aggressive NHL B-cell lymphomas. Pixantrone was deemed to be contraindicated in patients with uncontrolled cardiovascular disease. Despite a low rate of cardiotoxicity of pixantrone reported in clinical trials, the panel recommended that all patients receiving pixantrone should undergo periodical cardiac monitoring.

Monotherapy with pixantrone in histologically confirmed relapsed or refractory aggressive B-cell non-Hodgkin lymphoma: post-hoc analyses from a phase III trial

This post hoc analysis of a phase 3 trial explored the effect of pixantrone in patients (50 pixantrone, 47 comparator) with relapsed or refractory aggressive B‐cell non‐Hodgkin lymphoma (NHL) confirmed by centralized histological review. Patients received 28‐d cycles of 85 mg/m² pixantrone dimaleate (equivalent to 50 mg/m² in the approved formulation) on days 1, 8 and 15, or comparator. The population was subdivided according to previous rituximab use and whether they received the study treatment as 3rd or 4th line. Median number of cycles was 4 (range, 2–6) with pixantrone and 3 (2–6) with comparator. In 3rd or 4th line, pixantrone was associated with higher complete response (CR) (23·1% vs. 5·1% comparator, P = 0·047) and overall response rate (ORR, 43·6% vs. 12·8%, P = 0·005). In 3rd or 4th line with previous rituximab (20 pixantrone, 18 comparator), pixantrone produced better ORR (45·0% vs. 11·1%, P = 0·033), CR (30·0% vs. 5·6%, P = 0·093) and progression‐free survival (median 5·4 vs. 2·8 months, hazard ratio 0·52, 95% confidence interval 0·26–1·04) than the comparator. Similar results were found in patients without previous rituximab. There were no unexpected safety issues. Pixantrone monotherapy is more effective than comparator in relapsed or refractory aggressive B‐cell NHL in the 3rd or 4th line setting, independently of previous rituximab.

Targeting endothelial cell metabolism for cardio-protection from the toxicity of antitumor agents

The vascular endothelium plays a fundamental role in the maintenance of tissue homeostasis, regulating local blood flow and other physiological processes. Chemotherapeutic drugs and target therapies, including antiangiogenic drugs targeting vascular endothelial growth factor (VEGF) or its receptors, not only efficiently act against tumor growth, but may also induce endothelial dysfunction and cardiovascular toxicity. Continued research efforts aim to better understand, prevent and mitigate these chemotherapy associated cardiovascular diseases. Conventional chemotherapeutic agents, such as anthracyclines, platinum compounds, and taxanes, and newer targeted agents, such as bevacizumab, trastuzumab, and tyrosine kinase inhibitors, have known risk of cardiovascular toxicity, which can limit their effectiveness by promoting increased morbidity and/or mortality. This review describes a) the activity of anticancer agents in inducing endothelial dysfunction, b) the metabolic pathways and signalling cascades which may be targeted by protective agents able to maintain or restore endothelial cell function, such as endothelial nitric oxide synthase/fibroblast growth factor-2 (eNOS-FGF-2) pathway, and c) the drugs/strategies reported to improve endothelial function and to reduce the risks of cardiovascular diseases such as angiotensin converting enzyme inhibitors (ACEi) and beta blockers, that are fundamental therapies in chronic heart failure (HF), as well as non-standard HF treatments such ad nitric oxide donors and antioxidant strategies. There is increasing interest in whether ACEi, beta-blockers, and/or statins might prevent and/or therapeutically control cardiotoxic effects in cancer patients. Maintaining endothelial function during or following treatments with chemotherapeutic agents, without affecting anti-tumor drug-effectiveness, is essential for preserving or recovering cardiovascular homeostasis. In this respect, the early detection and immediate therapy of cardiovascular toxicity appear crucial for substantial recovery of cardiac function in cancer patients.

Inhibition of human anthracycline reductases by emodin - A possible remedy for anthracycline resistance

The clinical application of anthracyclines, like daunorubicin and doxorubicin, is limited by two factors: dose-related cardiotoxicity and drug resistance. Both have been linked to reductive metabolism of the parent drug to their metabolites daunorubicinol and doxorubicinol, respectively. These metabolites show significantly less anti-neoplastic properties as their parent drugs and accumulate in cardiac tissue leading to chronic cardiotoxicity. Therefore, we aimed to identify novel and potent natural inhibitors for anthracycline reductases, which enhance the anticancer effect of anthracyclines by preventing the development of anthracycline resistance. Human enzymes responsible for the reductive metabolism of daunorubicin were tested for their sensitivity towards anthrachinones, in particular emodin and anthraflavic acid. Intense inhibition kinetic data for the most effective daunorubicin reductases, including IC50- and Ki-values, the mode of inhibition, as well as molecular docking, were compiled. Subsequently, a cytotoxicity profile and the ability of emodin to reverse daunorubicin resistance were determined using multiresistant A549 lung cancer and HepG2 liver cancer cells. Emodin potently inhibited the four main human daunorubicin reductases in vitro. Further, we could demonstrate that emodin is able to synergistically sensitize human cancer cells towards daunorubicin at clinically relevant concentrations. Therefore, emodin may yield the potential to enhance the therapeutic effectiveness of anthracyclines by preventing anthracycline resistance via inhibition of the anthracycline reductases. In symphony with its known pharmacological properties, emodin might be a compound of particular interest in the management of anthracycline chemotherapy efficacy and their adverse effects.

Mechanisms of Action and Reduced Cardiotoxicity of Pixantrone; a Topoisomerase II Targeting Agent with Cellular Selectivity for the Topoisomerase IIα Isoform

Pixantrone is a new noncardiotoxic aza-anthracenedione anticancer drug structurally related to anthracyclines and anthracenediones, such as doxorubicin and mitoxantrone. Pixantrone is approved in the European Union for the treatment of relapsed or refractory aggressive B cell non-Hodgkin lymphoma. This study was undertaken to investigate both the mechanism(s) of its anticancer activity and its relative lack of cardiotoxicity. Pixantrone targeted DNA topoisomerase IIα as evidenced by its ability to inhibit kinetoplast DNA decatenation; to produce linear double-strand DNA in a pBR322 DNA cleavage assay; to produce DNA double-strand breaks in a cellular phospho-histone γH2AX assay; to form covalent topoisomerase II-DNA complexes in a cellular immunodetection of complex of enzyme-to-DNA assay; and to display cross-resistance in etoposide-resistant K562 cells. Pixantrone produced semiquinone free radicals in an enzymatic reducing system, although not in a cellular system, most likely due to low cellular uptake. Pixantrone was 10- to 12-fold less damaging to neonatal rat myocytes than doxorubicin or mitoxantrone, as measured by lactate dehydrogenase release. Three factors potentially contribute to the reduced cardiotoxicity of pixantrone. First, its lack of binding to iron(III) makes it unable to induce iron-based oxidative stress. Second, its low cellular uptake may limit its ability to produce semiquinone free radicals and redox cycle. Finally, because the β isoform of topoisomerase II predominates in postmitotic cardiomyocytes, and pixantrone is demonstrated in this study to be selective for topoisomerase IIα in stabilizing enzyme-DNA covalent complexes, the attenuated cardiotoxicity of this agent may also be due to its selectivity for targeting topoisomerase IIα over topoisomerase IIβ.

Nuclear Trapping through Inhibition of Exosomal Export by Indomethacin Increases Cytostatic Efficacy of Doxorubicin and Pixantrone

PURPOSE

Although R-CHOP-based immunochemotherapy cures significant proportions of patients with aggressive B-cell lymphoma, tumor cell susceptibility to chemotherapy varies, with mostly fatal outcome in cases of resistant disease. We and others have shown before that export of cytostatic drugs contributes to drug resistance. Now we provide a novel approach to overcome exosome-mediated drug resistance in aggressive B-cell lymphomas.

EXPERIMENTAL DESIGN

We used well-established centrifugation protocols to purify exosomes from DLBCL cell lines and detected anthracyclines using FACS and HPLC. We used shRNA knockdown of ABCA3 to determine ABCA3 dependence of chemotherapy susceptibility and monitored ABCA3 expression after indomethacin treatment using qPCR. Finally, we established an in vivo assay using a chorioallantoic membrane (CAM) assay to determine the synergy of anthracycline and indomethacin treatment.

RESULTS

We show increased efficacy of the anthracycline doxorubicin and the anthracenedione pixantrone by suppression of exosomal drug resistance with indomethacin. B-cell lymphoma cells in vitro efficiently extruded doxorubicin and pixantrone, in part compacted in exosomes. Exosomal biogenesis was critically dependent on the expression of the ATP-transporter A3 (ABCA3). Genetic or chemical depletion of ABCA3 augmented intracellular retention of both drugs and shifted the subcellular drug accumulation to prolonged nuclear retention. Indomethacin increased the cytostatic efficacy of both drugs against DLBCL cell lines in vitro and in vivo in a CAM assay.

CONCLUSIONS

We propose pretreatment with indomethacin toward enhanced antitumor efficacy of anthracyclines and anthracenediones.

Pixantrone: a B-cell-depleting immunosuppressant for multiple sclerosis patients with active disease

Background:

Mitoxantrone has been approved for patients with worsening relapsing–remitting (RR) or secondary progressive multiple sclerosis (SPMS), but its long-term use is limited by its cardiotoxicity. Pixantrone (PIX) is an analog of mitoxantrone.

Objectives:

The aim of this open-label, multicenter, noncomparative Phase I/II trial was to explore the immunosuppressive effect of PIX, its impact on clinical disease activity and cerebral gadolinium-enhanced (Gd+) lesions, and its safety.

Methods:

Eighteen patients with active RRMS and SPMS (⩾ 1 cerebral Gd+ lesion) despite approved immunomodulatory therapy received four intravenous PIX injections every 21 days. A neurological examination, hematology, lymphocyte subsets, and biochemistry were performed at Day 1, Weeks 3, 6 and 9, and Months 3, 6, 9 and 12. Echocardiography was performed before each infusion, at Months 3, 6 and 12. Cerebral MRI was performed at baseline, and at Months 6 and 12.

Results:

CD19+ cells were reduced by 95% at Month 3 and by 47% at Month 12. Gd+ lesions were reduced by 86% at Month 12 ( p = 0.01). The annual relapse rate was reduced by 87% ( p < 10−4). Two patients experienced a transient reduction in left ventricular fraction.

Conclusion:

These preliminary data indicate the efficacy of PIX in active RRMS and SPMS.

Two phase I dose-escalation/pharmacokinetics studies of low temperature liposomal doxorubicin (LTLD) and mild local hyperthermia in heavily pretreated patients with local regionally recurrent breast cancer

Purpose

Unresectable chest wall recurrences of breast cancer (CWR) in heavily pretreated patients are especially difficult to treat. We hypothesised that thermally enhanced drug delivery using low temperature liposomal doxorubicin (LTLD), given with mild local hyperthermia (MLHT), will be safe and effective in this population.

Patients and methods

This paper combines the results of two similarly designed phase I trials. Eligible CWR patients had progressed on the chest wall after prior hormone therapy, chemotherapy, and radiotherapy. Patients were to get six cycles of LTLD every 21–35 days, followed immediately by chest wall MLHT for 1 hour at 40–42 °C. In the first trial 18 subjects received LTLD at 20, 30, or 40 mg/m²; in the second trial, 11 subjects received LTLD at 40 or 50 mg/m².

Results

The median age of all 29 patients enrolled was 57 years. Thirteen patients (45%) had distant metastases on enrolment. Patients had received a median dose of 256 mg/m² of prior anthracyclines and a median dose of 61 Gy of prior radiation. The median number of study treatments that subjects completed was four. The maximum tolerated dose was 50 mg/m², with seven subjects (24%) developing reversible grade 3–4 neutropenia and four (14%) reversible grade 3–4 leucopenia. The rate of overall local response was 48% (14/29, 95% CI: 30–66%), with. five patients (17%) achieving complete local responses and nine patients (31%) having partial local responses.

Conclusion

LTLD at 50 mg/m² and MLHT is safe. This combined therapy produces objective responses in heavily pretreated CWR patients. Future work should test thermally enhanced LTLD delivery in a less advanced patient population.

The concomitant management of cancer therapy and cardiac therapy

Antitumor drugs have long been known to introduce a measurable risk of cardiovascular events. Cardio-Oncology is the discipline that builds on collaboration between cardiologists and oncologists and aims at screening, preventing or minimizing such a risk. Overt concern about "possible" cardiovascular toxicity might expose cancer patients to the risk of tumor undertreatment and poor oncologic outcome. Careful analysis of risk:benefit balance is therefore central to the management of patients exposed to potentially cardiotoxic drugs. Concomitant or sequential management of cardiac and cancer therapies should also be tailored to the following strengths and weaknesses: i) molecular mechanisms and clinical correlates of cardiotoxicity have been characterized to some extent for anthracyclines but not for other chemotherapeutics or new generation "targeted" drugs, ii) anthracyclines and targeted drugs cause different mechanisms of cardiotoxicity (type I versus type II), and this classification should guide strategies of primary or secondary prevention, iii) with anthracyclines and nonanthracycline chemotherapeutics, cardiovascular events may occur on treatment as well as years or decades after completing chemotherapy, iv) some patients may be predisposed to a higher risk of cardiac events but there is a lack of prospective studies that characterized optimal genetic tests and pharmacologic measures to minimize excess risk, v) clinical toxicity may be preceded by asymptomatic systolic and/or diastolic dysfunction that necessitates innovative mechanism-based pharmacologic treatment, and vi) patient-tailored pharmacologic correction of comorbidities is important for both primary and secondary prevention. Active collaboration of physicians with laboratory scientists is much needed for improving management of cardiovascular sequelae of antitumor therapy. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

Pixantrone for the treatment of adult patients with relapsed or refractory aggressive non-Hodgkin B-cell lymphomas

Treatment of patients with relapsed or refractory aggressive non-Hodgkin B-cell lymphoma remains an unmet clinical need, and the progressive myocardial toxicity related to cumulative, dose-dependent damage induced by anthracyclines represents a tricky issue in the planning of therapy. Pixantrone is a promising aza-anthracenedione with reduced cardiotoxicity and significant antineoplastic activity, and has been investigated in solid and hematologic tumors in several Phase I, II, and III trials. The aim of this review is to summarize the data reported so far on pixantrone as a salvage therapy in relapsed/refractory non-Hodgkin B-cell lymphoma.

Initial testing (stage 1) of the topoisomerase II inhibitor pixantrone, by the pediatric preclinical testing program

Pixantrone, a novel aza-anthracenedione with cytotoxic activity, was tested against the PPTP in vitro panel (3.0 nM to 30.0 μM) and against a limited panel of PPTP Wilms tumors and sarcomas (7.5 mg/kg) administered intravenously using an every 4 day × 3 schedule. In vitro pixantrone showed a median relative IC50 value of 54 nM (range <3 nM to 1.03 μM). In vivo pixantrone induced significant differences in EFS distribution compared to controls in two of eight solid tumor xenografts at dose levels relevant to human drug exposure. A complete response was observed for one Wilms tumor xenograft.

Treatment challenges in the management of relapsed or refractory non-Hodgkin's lymphoma - novel and emerging therapies

Over the last few decades, advances in immunochemotherapy have led to dramatic improvement in the prognosis of non-Hodgkin's lymphoma (NHL). Despite these advances, relapsed and refractory disease represents a major treatment challenge. For both aggressive and indolent subtypes of NHL, there is no standard of care for salvage regimens, with prognosis after relapse remaining relatively poor. Nevertheless, there are multiple emerging classes of targeted therapies for relapsed/refractory disease, including monoclonal antibodies, antibody- drug conjugates, radioimmunotherapy, small-molecule inhibitors of cell-growth pathways, and novel chemotherapy agents. This review will discuss treatment challenges of NHL, current available salvage regimens for relapsed/refractory NHL, and the safety and efficacy of novel emerging therapies.