Topotecan, cyclophosphamide, and etoposide (TCE) in the treatment of high-risk neuroblastoma. Results of a phase-II trial

Pharmacologically Targeting Ferroptosis and Cuproptosis in Neuroblastoma

Neuroblastoma is a deadly pediatric cancer that originates from the neural crest and frequently develops in the abdomen or adrenal gland. Although multiple approaches, including chemotherapy, radiotherapy, targeted therapy, and immunotherapy, are recommended for treating neuroblastoma, the tumor will eventually develop resistance, leading to treatment failure and cancer relapse. Therefore, a firm understanding of the molecular mechanisms underlying therapeutic resistance is vital for the development of new effective therapies. Recent research suggests that cancer-specific modifications to multiple subtypes of nonapoptotic regulated cell death (RCD), such as ferroptosis and cuproptosis, contribute to therapeutic resistance in neuroblastoma. Targeting these specific types of RCD may be viable novel targets for future drug discovery in the treatment of neuroblastoma. In this review, we summarize the core mechanisms by which the inability to properly execute ferroptosis and cuproptosis can enhance the pathogenesis of neuroblastoma. Therefore, we focus on emerging therapeutic compounds that can induce ferroptosis or cuproptosis, delineating their beneficial pharmacodynamic effects in neuroblastoma treatment. Cumulatively, we suggest that the pharmacological stimulation of ferroptosis and ferroptosis may be a novel and therapeutically viable strategy to target neuroblastoma.

Salvage chemotherapy regimens with arsenic trioxide for relapsed or refractory neuroblastoma: a promising approach

In patients with relapsed or refractory neuroblastoma (NB), the limited efficacy of conventional chemotherapies necessitates the exploration of new treatment options. Previous studies have highlighted the anti-tumor properties of arsenic trioxide (ATO) in high-risk NB (HR-NB). This study aims to assess the effectiveness and safety of ATO combined with salvage chemotherapy regimens, featuring cyclophosphamide and topotecan, as a foundational treatment for children with relapsed or refractory NB. Eleven patients (four relapsed, seven refractory NB) were retrospectively analyzed for efficacy and treatment relevance. Salvage treatments, incorporating ATO (0.18 mg/kg daily for 8 h intravenously on days 1 to 10), were administered upon disease progression or relapse, with assessments conducted every two cycles. Treatments had 63.6% efficacy, with six cases of partial response, one case of stable disease, and four cases of disease progression. The overall response rate was 54.5%, and the disease control rate was 63.6%. Importantly, the systemic toxicity experienced by patients following salvage chemotherapy with ATO was mild. Salvage chemotherapy regimens featuring ATO demonstrated potential for prolonging disease stabilization for relapsed or refractory HR-NB patients, exhibiting both favorable efficacy and safety profiles. This suggests further clinical exploration and promotion of this therapeutic approach in the treatment of NB.

The Impact of 131I-Metaiodobenzylguanidine as a Conditioning Regimen of Tandem High-Dose Chemotherapy and Autologous Stem Cell Transplantation for High-Risk Neuroblastoma

BACKGROUND

The optimal conditioning regimen of tandem high-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT) for high-risk neuroblastoma (HR-NBL) has not been established. The efficacy of 131I-MIBG therapy is under exploration in newly diagnosed HR-NBL patients. Here, we compared the outcomes of tandem HDC/ASCT between the 131I-MIBG combination and non-MIBG groups.

METHODS

We retrospectively analyzed the clinical data of 33 HR-NBL patients who underwent tandem HDC/ASCT between 2007 and 2021 at the Seoul National University Children's Hospital.

RESULTS

The median age at diagnosis was 3.6 years. 131I-MIBG was administered to 13 (39.4%) of the patients. Thirty patients (90.9%) received maintenance therapy after tandem HDC/ASCT, twenty-two were treated with isotretinoin ± interleukin-2, and eight received salvage chemotherapy. The five-year overall survival (OS) and event-free survival (EFS) rates of all patients were 80.4% and 69.4%, respectively. Comparing the 131I-MIBG combined group and other groups, the five-year OS rates were 82.1% and 79.7% (p = 0.655), and the five-year EFS rates were 69.2% and 69.6% (p = 0.922), respectively. Among the adverse effects of grade 3 or 4, the incidence of liver enzyme elevation was significantly higher in the non-131I-MIBG group.

CONCLUSIONS

Although tandem HDC/ASCT showed promising outcomes, the 131I-MIBG combination did not improve survival rates.

Dinutuximab beta plus conventional chemotherapy for relapsed/refractory high-risk neuroblastoma: A single-center experience

Background

Relapsed/refractory high-risk neuroblastoma has a dismal prognosis. Anti-GD2-mediated chemo-immunotherapy has a notable anti-tumor activity in patients with relapsed/refractory high-risk neuroblastoma. The purpose of this study was to analyze the efficacy and safety of the combination of immunotherapy with dinutuximab beta (DB) and chemotherapy in patients with relapsed/refractory high-risk neuroblastoma.

Methods

All patients received the Turkish Pediatric Oncology Group NB 2009 national protocol for HR-NB treatment at the time of diagnosis. Salvage treatments were administered after progression or relapse. The patients who could not achieve remission in primary or metastatic sites were included in the study. The most common chemotherapy scheme was irinotecan and temozolomide. DB was administered intravenously for 10 days through continuous infusion with 10 mg/m² per day. The patients received 2 to 14 successive cycles with duration of 28 days each. Disease assessment was performed after cycles 2, 4, and 6 and every 2 to 3 cycles thereafter.

Results

Between January 2020 and March 2022, nineteen patients received a total of 125 cycles of DB and chemotherapy. Objective responses were achieved in 12/19 (63%) patients, including complete remission in 6/19 and partial response in 6/19. Stable disease was observed in two patients. The remaining five patients developed bone/bone marrow and soft tissue progression after 2-4 cycles of treatment. The most common Grade ≥3 toxicities were leukopenia, thrombocytopenia, hypertransaminasemia, fever, rash/itching and capillary leak syndrome, respectively.

Conclusion

Our study results suggest that DB-based chemo-immunotherapy seems to be suitable with encouraging response rates in patients with relapsed/refractory high-risk neuroblastoma.

Early-phase clinical trial eligibility and response evaluation criteria for refractory, relapsed, or progressive neuroblastoma: A consensus statement from the National Cancer Institute Clinical Trials Planning Meeting

BACKGROUND

International standardized criteria for eligibility, evaluable disease sites, and disease response assessment in patients with refractory, progressive, or relapsed high-risk neuroblastoma enrolled in early-phase clinical trials are lacking.

METHODS

A National Cancer Institute-sponsored Clinical Trials Planning Meeting was convened to develop an international consensus to refine the tumor site eligibility criteria and evaluation of disease response for early-phase clinical trials in children with high-risk neuroblastoma.

RESULTS

Standardized data collection of patient and disease characteristics (including specified genomic data), eligibility criteria, a definition of evaluable disease, and response evaluations for primary and metastatic sites of disease were developed. Eligibility included two distinct patient groups: progressive disease and refractory disease. The refractory disease group was subdivided into responding persistent disease and stable persistent disease to better capture the clinical heterogeneity of refractory neuroblastoma. Requirements for defining disease evaluable for a response assessment were provided; they included requirements for biopsy to confirm viable neuroblastoma and/or ganglioneuroblastoma in those patients with soft tissue or bone disease not avid for iodine-123 meta-iodobenzylguanidine. Standardized evaluations for response components and time intervals for response evaluations were established.

CONCLUSIONS

The use of international consensus eligibility, evaluability, and response criteria for early-phase clinical studies will facilitate the collection of comparable data across international trials and promote more rapid identification of effective treatment regimens for high-risk neuroblastoma.

Targeting RAS in neuroblastoma: Is it possible?

Neuroblastoma is a common solid tumor in children and a leading cause of cancer death in children. Neuroblastoma exhibits genetic, morphological, and clinical heterogeneity that limits the efficacy of current monotherapies. With further research on neuroblastoma, the pathogenesis of neuroblastoma is found to be complex, and more and more treatment therapies are needed. The importance of personalized therapy is growing. Currently, various molecular features, including RAS mutations, are being used as targets for the development of new therapies for patients with neuroblastoma. A recent study found that RAS mutations are frequently present in recurrent neuroblastoma. RAS mutations have been shown to activate the MAPK pathway and play an important role in neuroblastoma. Treating RAS mutated neuroblastoma is a difficult challenge, but many preclinical studies have yielded effective results. At the same time, many of the therapies used to treat RAS mutated tumors also have good reference values for treating RAS mutated neuroblastoma. The success of KRAS-G12C inhibitors has greatly stimulated confidence in the direct suppression of RAS. This review describes the biological role of RAS and the frequency of RAS mutations in neuroblastoma. This paper focuses on the strategies, preclinical, and clinical progress of targeting carcinogenic RAS in neuroblastoma, and proposes possible prospects and challenges in the future.

Hypercalcemia is a frequent side effect of 13-cis-retinoic acid treatment in patients with high-risk neuroblastoma

PURPOSE

13-cis-Retinoic acid (13-cisRA) is used as a postconsolidation treatment in patients with high-risk neuroblastoma. Hypercalcemia is a known side effect of retinoids. Frequency, symptoms, treatment, and risk factors for hypercalcemia were analyzed.

PATIENTS

Data were retrospectively analyzed for 350 patients registered in the German Neuroblastoma trials NB97 and NB04 who were treated with high-risk protocols-including myeloablative chemotherapy with autologous stem cell transplantation (SCT) or maintenance therapy-and had received 13-cisRA between January 1, 2000 and December 31, 2010.

RESULTS

Hypercalcemia was reported in 78 patients (22.3%), and 37 patients (10.6%) developed Common Terminology Criteria for Adverse Events (CTCAE) grade 3 or 4 hypercalcemia. The calcium levels were 2.5-4.6 mmol/L (median 3.1 mmol/L). Patients with a single kidney were at a higher risk of developing hypercalcemia (p = .001). Regarding postinduction treatment, 69 of 280 patients with SCT (24.6%) and nine of 70 patients without SCT (12.9%) developed hypercalcemia during 13-cisRA treatment (p = .037). Most patients developed hypercalcemia in the first cycle of 13-cisRA, and only in a single cycle. Hypercalcemia symptoms were frequent but moderate. In most patients, treatment with 13-cisRA was continued without dose reduction in subsequent cycles.

CONCLUSION

In this cohort, grades 3 and 4 hypercalcemia were observed more often than previously reported. A single kidney and pretreatment with myeloablative chemotherapy with stem cell transplantation were identified as potential risk factors for the development of hypercalcemia.

Neuroblastoma xenograft models demonstrate the therapeutic potential of 177Lu-octreotate

BACKGROUND

Neuroblastoma (NB) is one of the most frequently diagnosed tumors in infants. NB is a neuroendocrine tumor type with various characteristics and features, and with diverse outcome. The most malignant NBs have a 5-year survival rate of only 40-50%, indicating the need for novel and improved treatment options. 177Lu-octreotate is routinely administered for treatment of neuroendocrine tumors overexpressing somatostatin receptors (SSTR). The aim of this study was to examine the biodistribution of 177Lu-octreotate in mice bearing aggressive human NB cell lines, in order to evaluate the potential usefulness of 177Lu-octreotate for treatment of NB.

METHODS

BALB/c nude mice bearing CLB-BAR, CLB-GE or IMR-32 tumor xenografts (n = 5-7/group) were i.v. injected with 0.15 MBq, 1.5 MBq or 15 MBq 177Lu-octreotate and sacrificed 1 h, 24 h, 48 h and 168 h after administration. The radioactivity concentration was determined for collected tissue samples, tumor-to-normal-tissue activity concentration ratios (T/N) and mean absorbed dose for each tissue were calculated. Immunohistochemical (IHC) staining for SSTR1-5, and Ki67 were carried out for tumor xenografts from the three cell lines.

RESULTS

High 177Lu concentration levels and T/N values were observed in all NB tumors, with the highest for CLB-GE tumor xenografts (72%IA/g 24 h p.i.; 1.5 MBq 177Lu-octreotate). The mean absorbed dose to the tumor was 6.8 Gy, 54 Gy and 29 Gy for CLB-BAR, CLB-GE and IMR-32, respectively, p.i. of 15 MBq 177Lu-octreotate. Receptor saturation was clearly observed in CLB-BAR, resulting in higher concentration levels in the tumor when lower activity levels where administered. IHC staining demonstrated highest expression of SSTR2 in CLB-GE, followed by CLB-BAR and IMR-32.

CONCLUSION

T/N values for all three human NB tumor xenograft types investigated were high relative to previously investigated neuroendocrine tumor types. The results indicate a clear potential of 177Lu-octreotate as a therapeutic alternative for metastatic NB.

Advances in pharmacotherapy for neuroblastoma

INTRODUCTION

Neuroblastoma is the most prevalent cancer type diagnosed within the first year after birth and accounts for 15% of deaths from pediatric cancer. Despite the improvements in survival rates of patients with neuroblastoma, the incidence of the disease has increased over the last decade. Neuroblastoma tumor cells harbor a vast range of variable and heterogeneous histochemical and genetic alterations which calls for the need to administer individualized and targeted therapies to induce tumor regression in each patient.

AREAS COVERED

This paper provides reviews the recent clinical trials which used chemotherapeutic and/or targeted agents as either monotherapies or in combination to improve the response rate in patients with neuroblastoma, and especially high-risk neuroblastoma. It also reviews some of the prominent preclinical studies which can provide the rationale for future clinical trials.

EXPERT OPINION

Although some distinguished advances in pharmacotherapy have been made to improve the survival rate and reduce adverse events in patients with neuroblastoma, a more comprehensive understanding of the mechanisms of tumorigenesis, resistance to therapies or relapse, identifying biomarkers of response to each specific drug, and developing predictive preclinical models of the tumor can lead to further breakthroughs in the treatment of neuroblastoma.

Thiotepa-melphalan myeloablative therapy for high-risk neuroblastoma

BACKGROUND

Appropriate high-dose chemotherapy (HDC) for high-risk neuroblastoma has not yet been established. In Japan, a unique HDC regimen that comprises two cycles of a total of 800 mg/m² of thiotepa and a total of 280 mg/m² of melphalan is widely utilized.

METHODS

To evaluate the safety and efficacy of this thiotepa-melphalan high-dose therapy for high-risk neuroblastoma, we reviewed the medical records of 41 patients with high-risk neuroblastoma who underwent this regimen followed by autologous peripheral blood stem cell rescue between 2002 and 2012. MYCN-amplified high-risk neuroblastomas were observed in 23 patients. All patients underwent intensive multidrug induction chemotherapy, but none underwent anti-GD2 antibody immunotherapy. The primary tumor was resected at the adequate time point.

RESULTS

The median follow-up duration for living patients was 9.2 years (range 5.5-14.0 years). The 5-year event-free survival (EFS) and overall survival from treatment initiation were 41.5 ± 7.7% and 56.1 ± 7.8%, respectively. The 5-year EFS of MYCN-amplified high-risk neuroblastoma patients was 60.9 ± 10.2%, which was significantly superior compared with those with MYCN-nonamplified high-risk neuroblastoma (16.7 ± 8.8%; p < .001). MYCN amplification was the most favorable prognostic factor for EFS (hazard ratio = 0.29; 95% confidence interval = 0.12-0.66). Of the 41 patients, three died because of regimen-related toxicity (infection, n = 2; microangiopathy, n = 1).

CONCLUSION

The thiotepa-melphalan high-dose therapy with thiotepa and melphalan may be effective for high-risk neuroblastoma. However, this regimen is toxic and warrants special attention in clinical practice.

Molecular targeting therapies for neuroblastoma: Progress and challenges

There is an urgent need to identify novel therapies for childhood cancers. Neuroblastoma is the most common pediatric solid tumor, and accounts for ~15% of childhood cancer‐related mortality. Neuroblastomas exhibit genetic, morphological and clinical heterogeneity, which limits the efficacy of existing treatment modalities. Gaining detailed knowledge of the molecular signatures and genetic variations involved in the pathogenesis of neuroblastoma is necessary to develop safer and more effective treatments for this devastating disease. Recent studies with advanced high‐throughput “omics” techniques have revealed numerous genetic/genomic alterations and dysfunctional pathways that drive the onset, growth, progression, and resistance of neuroblastoma to therapy. A variety of molecular signatures are being evaluated to better understand the disease, with many of them being used as targets to develop new treatments for neuroblastoma patients. In this review, we have summarized the contemporary understanding of the molecular pathways and genetic aberrations, such as those in MYCN, BIRC5, PHOX2B, and LIN28B, involved in the pathogenesis of neuroblastoma, and provide a comprehensive overview of the molecular targeted therapies under preclinical and clinical investigations, particularly those targeting ALK signaling, MDM2, PI3K/Akt/mTOR and RAS‐MAPK pathways, as well as epigenetic regulators. We also give insights on the use of combination therapies involving novel agents that target various pathways. Further, we discuss the future directions that would help identify novel targets and therapeutics and improve the currently available therapies, enhancing the treatment outcomes and survival of patients with neuroblastoma.

Gene Expression Signature of Acquired Chemoresistance in Neuroblastoma Cells

Drug resistance of childhood cancer neuroblastoma is a serious clinical problem. Patients with relapsed disease have a poor prognosis despite intense treatment. In the present study, we aimed to identify chemoresistance gene expression signatures in vincristine resistant neuroblastoma cells. We found that vincristine-resistant neuroblastoma cells formed larger clones and survived under reduced serum conditions as compared with non-resistant parental cells. To identify the possible mechanisms underlying vincristine resistance in neuroblastoma cells, we investigated the expression profiles of genes known to be involved in cancer drug resistance. This specific gene expression patterns could predict the behavior of a tumor in response to chemotherapy and for predicting the prognosis of high-risk neuroblastoma patients. Our signature could help chemoresistant neuroblastoma patients in avoiding useless and harmful chemotherapy cycles.

Dendrimer Nanodevices and Gallic Acid as Novel Strategies to Fight Chemoresistance in Neuroblastoma Cells

Human neuroblastoma (NB), a pediatric tumor inclined to relapse, after an initial response to therapy, usually develops resistance. Since several chemotherapeutics exert anticancer effect by increasing reactive oxygen species (ROS), NB cells overproduce antioxidant compounds becoming drugs-resistant. A strategy to sensitize NB cells to chemotherapy involves reducing their antioxidant defenses and inducing ROS overproduction. Concerning this, although affected by several issues that limit their clinical application, antioxidant/pro-oxidant polyphenols, such as gallic acid (GA), showed pro-oxidant anti-cancer effects and low toxicity for healthy cells, in several kind of tumors, not including NB. Herein, for the first time, free GA, two GA-dendrimers, and the dendrimer adopted as GA reservoir were tested on both sensitive and chemoresistant NB cells. The dendrimer device, administered at the dose previously found active versus sensitive NB cells, induced ROS-mediated death also in chemoresistant cells. Free GA proved a dose-dependent ROS-mediated cytotoxicity on both cell populations. Intriguingly, when administered in dendrimer formulations at a dose not cytotoxic for NB cells, GA nullified any pro-oxidant activity of dendrimer. Unfortunately, due to GA, nanoformulations were inactive on NB cells, but GA resized in nanoparticles showed considerable ability in counteracting, at low dose, ROS production and oxidative stress, herein induced by the dendrimer.

Extended induction chemotherapy does not improve the outcome for high-risk neuroblastoma patients: results of the randomized open-label GPOH trial NB2004-HR

BACKGROUND

Long-term survival of high-risk neuroblastoma patients is still below 50% despite intensive multimodal treatment. This trial aimed to address whether the addition of two topotecan-containing chemotherapy courses compared to standard induction therapy improves event-free survival (EFS) of these patients.

PATIENTS AND METHODS

An open-label, multicenter, prospective randomized controlled trial was carried out at 58 hospitals in Germany and Switzerland. Patients aged 1-21 years with stage 4 neuroblastoma and patients aged 6 months to 21 years with MYCN-amplified tumors were eligible. The primary endpoint was EFS. Patients were randomly assigned to standard induction therapy with six chemotherapy courses or to experimental induction chemotherapy starting with two additional courses of topotecan, cyclophosphamide, and etoposide followed by standard induction chemotherapy (eight courses in total). After induction chemotherapy, all patients received high-dose chemotherapy with autologous hematopoietic stem cell rescue and isotretinoin for consolidation. Radiotherapy was applied to patients with active tumors at the end of induction chemotherapy.

RESULTS

Of 536 patients enrolled in the trial, 422 were randomly assigned to the control arm (n = 211) and the experimental arm (n = 211); the median follow-up time was 3.32 years (interquartile range 1.65-5.92). At data lock, the 3-year EFS of experimental and control patients was 34% and 32% [95% confidence Interval (CI) 28% to 40% and 26% to 38%; P = 0.258], respectively. Similarly, the 3-year overall survival of the patients did not differ [54% and 48% (95% CI 46% to 62% and 40% to 56%), respectively; P = 0.558]. The response to induction chemotherapy was not different between the arms. The median number of non-fatal toxicities per patient was higher in the experimental group while the median number of toxicities per chemotherapy course was not different.

CONCLUSION

While the burden for the patients was increased by prolonging the induction chemotherapy and the toxicity, the addition of two topotecan-containing chemotherapy courses did not improve the EFS of high-risk neuroblastoma patients and thus cannot be recommended. CLINICAL TRIALS.

GOV NUMBER

NCT number 03042429.

In Silico Insights on GD2 : A Potential Target for Pediatric Neuroblastoma

Background:

Originating from the abnormal growth of neuroblasts, pediatric neuroblastoma affects the age group below 15 years. It is an aggressive heterogenous cancer with a high morbidity rate. Biological marker GD2 synthesised by the GD2 gene acts as a powerful predictor of neuroblastoma cells. GD2 gangliosides are sialic acid-containing glycosphingolipids. Differential expression during brain development governs the function of the GD2. The present study explains the interaction of the GD2 with its established inhibitors and discovers the compound having a high binding affinity against the target protein. Technically, during the development of new compounds through docking studies, the best drug among all pre-exist inhibitors was filtered. Hence in reference to the best docked compound, the study proceeded further.

Methodology:

The In silico approach provides a platform to determine and establish potential inhibitor against GD2 in Pediatric neuroblastoma. The 3D structure of GD2 protein was modelled by homology base fold methods using Smith-Watermans’ Local alignment. A total of 18 established potent compounds were subjected to molecular docking and Etoposide (CID: 36462) manifested the highest affinity. The similarity search presented 336 compounds similar to Etoposide.

Results:

Through virtual screening, the compound having PubChem ID 10254934 showed a better affinity towards GD2 than the established inhibitor. The comparative profiling of the two compounds based on various interactions such as H-bond interaction, aromatic interactions, electrostatic interactions and ADMET profiling and toxicity studies were performed using various computational tools.

Conclusion:

The docking separated the virtual screened drug (PubChemID: 10254934) from the established inhibitor with a better re-rank score of -136.33. The toxicity profile of the virtual screened drug was also lesser (less lethal) than the established drug. The virtual screened drug was observed to be bioavailable as it does not cross the blood-brain barrier. Conclusively, the virtual screened compound obtained in the present investigation is better than the established inhibitor and can be further augmented by In vitro analysis, pharmacodynamics and pharmacokinetic studies.

A systematic review of re-induction chemotherapy for children with relapsed high-risk neuroblastoma

BACKGROUND

Despite aggressive multimodal therapy, >50% of children with high-risk neuroblastoma (HRNB) relapse. Survival after relapse is rare, and no consensus currently exists on the most effective therapy.

OBJECTIVE

To conduct a systematic review of the literature on effectiveness of re-induction chemotherapy in children with relapsed HRNB.

METHODS

Database searches were performed to identify studies looking at response to 1st line chemotherapy for children >12 months at diagnosis with first relapse of HRNB. Studies not reporting separate outcomes for HRNB patients or of refractory patients only were excluded. Two independent reviewers extracted the data and assessed study quality using a modified Newcastle-Ottawa tool.

RESULTS

Nine studies were identified fitting the inclusion criteria. All except one were single arm cohorts, and two were retrospective database reviews from single centres. One was a multicentre randomised controlled trial. All used a version of the validated International Neuroblastoma Response Criteria with 8 recording best ever response and 1 at a specified time, and 5 had central review. The proportion of relapsed patients varied from 24 to 100% with 30-93% receiving upfront myeloablative therapy. The response rate varied from 6 to 64%; however, because of heterogeneity, studies were not directly comparable, and no single treatment emerged as the most effective re-induction therapy.

CONCLUSIONS

To date, there is no clear superior re-induction therapy for 1st relapse of HRNB. Randomised controlled trials with separate arms for relapsed versus refractory disease are needed to determine optimal re-induction chemotherapy to act as a backbone for testing newer targeted agents.

Etoposide-resistance in a neuroblastoma model cell line is associated with 13q14.3 mono-allelic deletion and miRNA-15a/16-1 down-regulation

Drug resistance is the major obstacle in successfully treating high-risk neuroblastoma. The aim of this study was to investigate the basis of etoposide-resistance in neuroblastoma. To this end, a MYCN-amplified neuroblastoma cell line (HTLA-230) was treated with increasing etoposide concentrations and an etoposide-resistant cell line (HTLA-ER) was obtained. HTLA-ER cells, following etoposide exposure, evaded apoptosis by altering Bax/Bcl2 ratio. While both cell populations shared a homozygous TP53 mutation encoding a partially-functioning protein, a mono-allelic deletion of 13q14.3 locus, where the P53 inducible miRNAs 15a/16-1 are located, and the consequent miRNA down-regulation were detected only in HTLA-ER cells. This event correlated with BMI-1 oncoprotein up-regulation which caused a decrease in p16 tumor suppressor content and a metabolic adaptation of HTLA-ER cells. These results, taken collectively, highlight the role of miRNAs 15a/16-1 as markers of chemoresistance.

Glutathione-mediated antioxidant response and aerobic metabolism: two crucial factors involved in determining the multi-drug resistance of high-risk neuroblastoma

Neuroblastoma, a paediatric malignant tumor, is initially sensitive to etoposide, a drug to which many patients develop chemoresistance. In order to investigate the molecular mechanisms responsible for etoposide chemoresistance, HTLA-230, a human MYCN-amplified neuroblastoma cell line, was chronically treated with etoposide at a concentration that in vitro mimics the clinically-used dose. The selected cells (HTLA-Chr) acquire multi-drug resistance (MDR), becoming less sensitive than parental cells to high doses of etoposide or doxorubicin. MDR is due to several mechanisms that together contribute to maintaining non-toxic levels of H₂O₂. In fact, HTLA-Chr cells, while having an efficient aerobic metabolism, are also characterized by an up-regulation of catalase activity and higher levels of reduced glutathione (GSH), a thiol antioxidant compound. The combination of such mechanisms contributes to prevent membrane lipoperoxidation and cell death. Treatment of HTLA-Chr cells with L-Buthionine-sulfoximine, an inhibitor of GSH biosynthesis, markedly reduces their tumorigenic potential that is instead enhanced by the exposure to N-Acetylcysteine, able to promote GSH synthesis.

Collectively, these results demonstrate that GSH and GSH-related responses play a crucial role in the acquisition of MDR and suggest that GSH level monitoring is an efficient strategy to early identify the onset of drug resistance and to control the patient's response to therapy.

Topotecan-Vincristine-Doxorubicin in Stage 4 High-Risk Neuroblastoma Patients Failing to Achieve a Complete Metastatic Response to Rapid COJEC: A SIOPEN Study

PURPOSE

Metastatic response to induction therapy for high-risk neuroblastoma is a prognostic factor. In the International Society of Paediatric Oncology Europe Neuroblastoma (SIOPEN) HR-NBL-1 protocol, only patients with metastatic complete response (CR) or partial response (PR) with ≤ three abnormal skeletal areas on iodine 123-metaiodobenzylguanidine ([123I]mIBG) scintigraphy and no bone marrow disease proceed to high dose therapy (HDT). In this study, topotecan-vincristine-doxorubicin (TVD) was evaluated in patients failing to achieve these criteria, with the aim of improving the metastatic response rate.

MATERIALS AND METHODS

Patients with metastatic high-risk neuroblastoma who had not achieved the SIOPEN criteria for HDT after induction received two courses of topotecan 1.5 mg/m2/day for 5 days, followed by a 48-hour infusion of vincristine, 2 mg/m2, and doxorubicin, 45 mg/m2.

RESULTS

Sixty-three patients were eligible and evaluable. Following two courses of TVD, four (6.4%) patients had an overall CR, while 28 (44.4%) had a PR with a combined response rate of 50.8% (95% confidence interval [CI], 37.9 to 63.6). Of these, 23 patients achieved a metastatic CR or a PR with ≤ 3 mIBG skeletal areas and no bone marrow disease (36.5%; 95% CI, 24.7 to 49.6) and were eligible to receive HDT. Toxicity was mostly haematological, affecting 106 of the 126 courses (84.1%; 95% CI, 76.5 to 90.0), and dose reduction was necessary in six patients. Stomatitis was the second most common nonhematological toxicity, occurring in 20 patients (31.7%).

CONCLUSION

TVD was effective in improving the response rate of high-risk neuroblastoma patients after induction with COJEC enabling them to proceed to HDT. However, the long-term benefits of TVD needs to be determined in randomized clinical trials.

Investigational drugs in phase II clinical trials for the treatment of neuroblastoma

INTRODUCTION

Neuroblastoma (NB) is an embryonal tumor originating from undifferentiated neural crest cell, highly heterogeneous ranging from spontaneous regression to progression despite multimodal treatments. Approximately, 20% of patients are refractory to frontline therapy and 50% will relapse/progress after an initial response. The overall five year survival for high-risk neuroblastoma ranges from 35-45%. Despite enhanced understanding of NB biology and the addition of myeloablative chemotherapy, isotretinoin and immunotherapy, survival for high risk NB remains less than 50%. Areas covered: This review summarizes and gives a critical overview of phase II trials investigating therapies for relapsed-refractory and high risk neuroblastoma. Expert opinion: Several novel molecules have been developed and are currently under investigation for the treatment of NB. The trend of novel targeted agents is one towards individualized, tailored therapy, based on the molecular and biological differences that characterize tumors that seem similar based solely on histological analysis. The task of developing new molecules is particularly difficult for NB, given the recurrent development of new patterns of drug resistance. However, even if current research is focused towards identifying the best treatments for each children and young adult with a NB defined disease, a deeper knowledge of the molecular biology and genetics is needed.

Irinotecan-temozolomide with temsirolimus or dinutuximab in children with refractory or relapsed neuroblastoma (COG ANBL1221): an open-label, randomised, phase 2 trial

BACKGROUND

Outcomes for children with relapsed and refractory neuroblastoma are dismal. The combination of irinotecan and temozolomide has activity in these patients, and its acceptable toxicity profile makes it an excellent backbone for study of new agents. We aimed to test the addition of temsirolimus or dinutuximab to irinotecan-temozolomide in patients with relapsed or refractory neuroblastoma.

METHODS

For this open-label, randomised, phase 2 selection design trial of the Children's Oncology Group (COG; ANBL1221), patients had to have histological verification of neuroblastoma or ganglioneuroblastoma at diagnosis or have tumour cells in bone marrow with increased urinary catecholamine concentrations at diagnosis. Patients of any age were eligible at first designation of relapse or progression, or first designation of refractory disease, provided organ function requirements were met. Patients previously treated for refractory or relapsed disease were ineligible. Computer-based randomisation with sequence generation defined by permuted block randomisation (block size two) was used to randomly assign patients (1:1) to irinotecan and temozolomide plus either temsirolimus or dinutuximab, stratified by disease category, previous exposure to anti-GD2 antibody therapy, and tumour MYCN amplification status. Patients in both groups received oral temozolomide (100 mg/m² per dose) and intravenous irinotecan (50 mg/m² per dose) on days 1-5 of 21-day cycles. Patients in the temsirolimus group also received intravenous temsirolimus (35 mg/m² per dose) on days 1 and 8, whereas those in the dinutuximab group received intravenous dinutuximab (17·5 mg/m² per day or 25 mg/m² per day) on days 2-5 plus granulocyte macrophage colony-stimulating factor (250 μg/m² per dose) subcutaneously on days 6-12. Patients were given up to a maximum of 17 cycles of treatment. The primary endpoint was the proportion of patients achieving an objective (complete or partial) response by central review after six cycles of treatment, analysed by intention to treat. Patients, families, and those administering treatment were aware of group assignment. This study is registered with ClinicalTrials.gov, number NCT01767194, and follow-up of the initial cohort is ongoing.

FINDINGS

Between Feb 22, 2013, and March 23, 2015, 36 patients from 27 COG member institutions were enrolled on this groupwide study. One patient was ineligible (alanine aminotransferase concentration was above the required range). Of the remaining 35 patients, 18 were randomly assigned to irinotecan-temozolomide-temsirolimus and 17 to irinotecan-temozolomide-dinutuximab. Median follow-up was 1·26 years (IQR 0·68-1·61) among all eligible participants. Of the 18 patients assigned to irinotecan-temozolomide-temsirolimus, one patient (6%; 95% CI 0·0-16·1) achieved a partial response. Of the 17 patients assigned to irinotecan-temozolomide-dinutuximab, nine (53%; 95% CI 29·2-76·7) had objective responses, including four partial responses and five complete responses. The most common grade 3 or worse adverse events in the temsirolimus group were neutropenia (eight [44%] of 18 patients), anaemia (six [33%]), thrombocytopenia (five [28%]), increased alanine aminotransferase (five [28%]), and hypokalaemia (four [22%]). One of the 17 patients assigned to the dinutuximab group refused treatment after randomisation; the most common grade 3 or worse adverse events in the remaining 16 patients evaluable for safety were pain (seven [44%] of 16), hypokalaemia (six [38%]), neutropenia (four [25%]), thrombocytopenia (four [25%]), anaemia (four [25%]), fever and infection (four [25%]), and hypoxia (four [25%]); one patient had grade 4 hypoxia related to therapy that met protocol-defined criteria for unacceptable toxicity. No deaths attributed to protocol therapy occurred.

INTERPRETATION

Irinotecan-temozolomide-dinutuximab met protocol-defined criteria for selection as the combination meriting further study whereas irinotecan-temozolomide-temsirolimus did not. Irinotecan-temozolomide-dinutuximab shows notable anti-tumour activity in patients with relapsed or refractory neuroblastoma. Further evaluation of biomarkers in a larger cohort of patients might identify those most likely to respond to this chemoimmunotherapeutic regimen.

FUNDING

National Cancer Institute.

Advances in emerging drugs for the treatment of neuroblastoma

INTRODUCTION

Neuroblastoma is the most common solid extracranial tumor of childhood. Outcome for children with high-risk neuroblastoma remains suboptimal. More than half of children diagnosed with high-risk neuroblastoma either do not respond to conventional therapies or relapse after treatment with dismal prognosis. Areas covered: This paper presents a short review of the state of the art in the current treatment of high-risk neuroblastoma. An updated review of new targeted therapies in this group of patients is also presented. Expert opinion: In order to improve prognosis for high-risk patients there is an urgent need to better understand spatial and temporal heterogeneity and obtain new predictive preclinical models in neuroblastoma. Combination strategies with conventional chemotherapy and/or other targeted therapies may overcome current ALK inhibitors resistance. Improvement of international and transatlantic cooperation to speed clinical trials accrual is needed.

Clinical research on rare diseases of children: neuroblastoma

PURPOSE

Early access to new treatment options should not preclude accurate research planning, especially for rare diseases and fragile populations. Taking neuroblastoma as a model case, we analyzed the rationale supporting the search for future therapeutic strategies in the light of preclinical and clinical evidence.

METHODS

We reviewed ongoing randomized trials of pharmacological interventions for the treatment of neuroblastoma retrieved by searching ClinicalTrials.gov and the European Union Clinical Trials Registry (last update March 2016).

RESULTS

Our search identified four randomized clinical trial reports. We found poor evidence from preclinical and early clinical research supporting their rationale. Their methodology was questionable too.

CONCLUSIONS

The urgency to cover unmet needs in difficult clinical settings like rare diseases, particularly those involving fragile populations, cannot justify disorderly research approaches. Under these circumstances, clinical questions should be properly identified and addressed to protect patients and avoid wasteful research.

Upfront treatment of high-risk neuroblastoma with a combination of 131I-MIBG and topotecan

BACKGROUND

(131)I-metaiodobenzylguanidine ((131) I-MIBG) has a significant anti-tumor effect against neuroblastoma (NBL). Topotecan (TPT) can act as a radio-sensitizer and can up-regulate (131) I-MIBG uptake in vitro in NBL.

AIM

Determine the efficacy of the combination of (131) I-MIBG with topotecan in newly diagnosed high-risk (HR) NBL patients.

METHODS

In a prospective, window phase II study, patients with newly diagnosed high-risk neuroblastoma were treated at diagnosis with two courses of (131) I-MIBG directly followed by topotecan (0.7 mg/m(2) for 5 days). After these two courses, standard induction treatment (four courses of VECI), surgery and myeloablative therapy (MAT) with autologous stem cell transplantation (ASCT) was given. Response was measured after two courses of (131) I-MIBG-topotecan and post MAT and ASCT. Hematologic toxicity and harvesting of stem cells were analysed. Topoisomerase-1 activity levels were analysed in primary tumor material.

RESULTS

Sixteen patients were included in the study; median age was 2.8 years. MIBG administered activity (AA) (median and range) of the first course was 0.5 (0.4-0.6) GBq/kg (giga Becquerel/kilogram) and of the second course 0.4 (0.3-0.5) GBq/kg. The overall objective response rate (ORR) after 2 × MIBG/TPT was 57%, the primary tumor RR was 94%, and bone marrow RR was 43%. The ORR post MAT and ASCT was 57%. Hematologic grade four toxicity: after first and second (131) I-MIBG (platelets 25/33%, neutrophils 13/33%, and hemoglobin 25/7%). Topoisomerase-1 activity levels were increased in 10/10 (100%) measured tumors.

CONCLUSIONS

Combination therapy with MIBG-topotecan is an effective window treatment in newly diagnosed high-risk neuroblastoma patients.

Effect of combined treatment with cyclophosphamidum and allicin on neuroblastoma-bearing mice

OBJECTIVE

To evaluate the efficacy of allicin combined with cyclophosphamide on neuroblastoma (NB)-bearing mice and explore the immunological mechanism in it.

METHODS

A total of 30 NB-bearing mice were equally randomized into model group, cyclophosphamide group and combined therapy group, 10 nudemice were set as normal saline (NS) group. Cyclophosphamide group and combined therapy group were weekly injected with 60 mg/kg cyclophosphamide for four weeks; besides, combined therapy group was given with allicin (10 mg/kg/d) by gastric perfusion for 4 weeks; model group and NS group were given with the same volume of NS. Serum VEGF content was detected by ELISA pre-treating (0 d) and on the 3rd d, 14th d and 28th d; on 29th d, all mice were sacrificed and the tumor, liver, spleen and thymic tissues were weighted. Tumors were made into paraffin section for detecting tumor cell apoptosis and proliferation by TUNEL and BrdU method, respectively. Survival curves were drawn by Kaplan-Meier method.

RESULTS

After treatment, both treatment groups relieved on viscera indexes, VEGF level, T cell subsets distribution and tumor growth and each index of combined therapy group was better than cyclophosphamide group (P<0.05 or 0.01); only combined therapy group could significantly increase the lifetime of NB-bearing mice (μ (2)=5.667, P=0.017).

CONCLUSIONS

Allicin can improve T cell subsets distribution and inhibit VEGF expression through its immunomodulatory activity, thereby improve the efficiency on NB in coordination with cyclophosphamide.

Additional Therapies to Improve Metastatic Response to Induction Therapy in Children With High-risk Neuroblastoma

Children with high-risk neuroblastoma who fail to achieve adequate metastatic response after induction chemotherapy have dismal outcome and new therapeutic strategies are needed. However, timing of introduction of novel agents still remains under discussion. Given an increase in number of phase I-II studies of molecularly targeted drugs in neuroblastoma, it is crucial to determine, as early as possible, which patients may be suitable candidates for new therapeutic strategies. This single-center retrospective analysis of patients with high-risk neuroblastoma showed that the addition of conventional chemotherapy improved the quality of metastatic response only for the group of patients with partial response. It is therefore proposed to develop stratification criteria for those patients very unlikely to benefit from a plethora of additional lines of treatment, but might benefit from introduction of novel agents.

Molecular profiling of childhood cancer: Biomarkers and novel therapies

BACKGROUND

Technological advances including high-throughput sequencing have identified numerous tumor-specific genetic changes in pediatric and adolescent cancers that can be exploited as targets for novel therapies.

SCOPE OF REVIEW

This review provides a detailed overview of recent advances in the application of target-specific therapies for childhood cancers, either as single agents or in combination with other therapies. The review summarizes preclinical evidence on which clinical trials are based, early phase clinical trial results, and the incorporation of predictive biomarkers into clinical practice, according to cancer type.

MAJOR CONCLUSIONS

There is growing evidence that molecularly targeted therapies can valuably add to the arsenal available for treating childhood cancers, particularly when used in combination with other therapies. Nonetheless the introduction of molecularly targeted agents into practice remains challenging, due to the use of unselected populations in some clinical trials, inadequate methods to evaluate efficacy, and the need for improved preclinical models to both evaluate dosing and safety of combination therapies.

GENERAL SIGNIFICANCE

The increasing recognition of the heterogeneity of molecular causes of cancer favors the continued development of molecularly targeted agents, and their transfer to pediatric and adolescent populations.

Striking dichotomy in outcome of MYCN-amplified neuroblastoma in the contemporary era

BACKGROUND

The authors exploited a large database to investigate the outcomes of patients with high-risk neuroblastoma in the contemporary era.

METHODS

All patients with high-risk neuroblastoma aged <12 years who were treated during induction at the authors' institution from 2000 through 2011 were studied, including 118 patients with MYCN-amplified [MYCN(+)] disease and 127 patients aged >18 months with MYCN-nonamplified [MYCN(-)] stage 4 disease.

RESULTS

A complete response/very good partial response (CR/VGPR) to induction was correlated with significantly superior event-free survival (EFS) (P < .001) and overall survival (OS) (P < .001) compared with a partial response or less. Patients with MYCN(+) and MYCN(-) disease had similar rates of CR/VGPR to induction (P = .366), and those with MYCN(+) and MYCN(-) disease who attained a CR/VGPR had similar EFS (P = .346) and OS (P = .542). In contrast, only MYCN(+) patients had progressive disease as a response to induction (P < .001), and early death from progressive disease (<366 days after diagnosis) was significantly more common (P < .001) among those with MYCN(+) disease. Overall, among patients who had a partial response or less, MYCN(+) patients had significantly inferior EFS (P < .001) and OS (P < .001) compared with MYCN(-) patients, which accounted for the significantly worse EFS (P = .008) and OS (P = .002) for the entire MYCN(+) cohort versus the MYCN(-) cohort.

CONCLUSIONS

Patients with MYCN(-), high-risk neuroblastoma display a broad, continuous spectrum with regard to response and outcome, whereas MYCN(+) patients either have an excellent response to induction associated with good long-term outcome or develop early progressive disease with a poor outcome. This extreme dichotomy in the clinical course of MYCN(+) patients points to underlying biologic differences with MYCN(+) neuroblastoma, the elucidation of which may have far-reaching implications, including improved risk classification at diagnosis and the identification of targets for treatment.

Phase II study of temozolomide in combination with topotecan (TOTEM) in relapsed or refractory neuroblastoma: a European Innovative Therapies for Children with Cancer-SIOP-European Neuroblastoma study

PURPOSE

To assess objective response rate (ORR) after two cycles of temozolomide in combination with topotecan (TOTEM) in children with refractory or relapsed neuroblastoma.

PATIENTS AND METHODS

This multicenter, non-randomised, phase II study included children with neuroblastoma according to a two-stage Simon design. Eligibility criteria included relapsed or refractory, measurable or metaiodobenzylguanidine (mIBG) evaluable disease, no more than two lines of prior treatment. Temozolomide was administered orally at 150mg/m(2) followed by topotecan at 0.75mg/m(2) intravenously for five consecutive days every 28days. Tumour response was assessed every two cycles according to International Neuroblastoma Response Criteria (INRC), and reviewed independently.

RESULTS

Thirty-eight patients were enroled and treated in 15 European centres with a median age of 5.4years. Partial tumour response after two cycles was observed in 7 out of 38 evaluable patients [ORR 18%, 95% confidence interval (CI) 8-34%]. The best ORR whatever the time of evaluation was 24% (95% CI, 11-40%) with a median response duration of 8.5months. Tumour control rate (complete response (CR)+partial response (PR)+mixed response (MR)+stable disease (SD)) was 68% (95% CI, 63-90%). The 12-months Progression-Free and Overall Survival were 42% and 58% respectively. Among 213 treatment cycles (median 4, range 1-12 per patient) the most common treatment-related toxicities were haematologic. Grade 3/4 neutropenia occurred in 62% of courses in 89% of patients, grade 3/4 thrombocytopenia in 47% of courses in 71% of patients; three patients (8%) had febrile neutropenia.

CONCLUSION

Temozolomide-Topotecan combination results in very encouraging ORR and tumour control in children with heavily pretreated recurrent and refractory neuroblastoma with favourable toxicity profile.

Critical role of STAT3 in IL-6-mediated drug resistance in human neuroblastoma

Drug resistance is a major cause of treatment failure in cancer. Here, we have evaluated the role of STAT3 in environment-mediated drug resistance (EMDR) in human neuroblastoma. We determined that STAT3 was not constitutively active in most neuroblastoma cell lines but was rapidly activated upon treatment with interleukin (IL)-6 alone and in combination with the soluble IL-6 receptor (sIL-6R). Treatment of neuroblastoma cells with IL-6 protected them from drug-induced apoptosis in a STAT3-dependent manner because the protective effect of IL-6 was abrogated in the presence of a STAT3 inhibitor and upon STAT3 knockdown. STAT3 was necessary for the upregulation of several survival factors such as survivin (BIRC5) and Bcl-xL (BCL2L1) when cells were exposed to IL-6. Importantly, IL-6-mediated STAT3 activation was enhanced by sIL-6R produced by human monocytes, pointing to an important function of monocytes in promoting IL-6-mediated EMDR. Our data also point to the presence of reciprocal activation of STAT3 between tumor cells and bone marrow stromal cells including not only monocytes but also regulatory T cells (Treg) and nonmyeloid stromal cells. Thus, the data identify an IL-6/sIL-6R/STAT3 interactive pathway between neuroblastoma cells and their microenvironment that contributes to drug resistance.

Current and future strategies for relapsed neuroblastoma: challenges on the road to precision therapy

More than half of the patients with high-risk neuroblastoma (NB) will relapse despite intensive multimodal therapy, with an additional 10% to 20% refractory to induction chemotherapy. Management of these patients is challenging, given disease heterogeneity, resistance, and organ toxicity including poor hematological reserve. This review will discuss the current treatment options and consider novel therapies on the horizon. Cytotoxic chemotherapy regimens for relapse and refractory NB typically center on the use of the camptothecins, topotecan and irinotecan, in combination with agents such as cyclophosphamide and temozolomide, with objective responses but poor long-term survival. I-meta-iodobenzylguanidine therapy is also effective for relapsed patients with meta-iodobenzylguanidine-avid disease, with objective responses in a third of cases. Immunotherapy with anti-GD2 has recently been incorporated into upfront therapy, but its role in the relapse setting remains uncertain, especially for patients with bulky disease. Future cell-based immunotherapies and other approaches may be able to overcome this limitation. Finally, many novel molecularly targeted agents are in development, some of which show specific promise for NB. Successful incorporation of these agents will require combinations with conventional cytotoxic chemotherapies, as well as the development of predictive biomarkers, to ultimately personalize approaches to patients with "targetable" molecular abnormalities.

Emerging drugs for neuroblastoma

INTRODUCTION

Neuroblastoma accounts for 8 - 10% of pediatric cancers and is responsible for 15% of childhood cancer deaths. Despite multimodality treatment, the overall survival (OS) and event-free survival (EFS) in high-risk patients remain suboptimal. More than half of children diagnosed with high-risk neuroblastoma either do not respond to conventional therapies or relapse after treatment.

AREAS COVERED

This review discusses about the unmet medical needs for new therapeutic options against high-risk neuroblastoma. New drugs and therapeutic strategies that are under development in clinical trials, which are currently recruiting patients.

EXPERT OPINION

There is a need to improve the response rate of induction chemotherapy, which is not effective in a third of patients and also the other components of the current treatment, little efficacious in avoiding the relapses. Few drugs have been introduced as upfront therapy in the last years. Topotecan, irinotecan and temozolomide are expected to improve the response in high-risk neuroblastoma, but their impact on OS and EFS is unknown. Anti-GD2 antibodies combined with other immunomodulators (IL-2, GM-CSF) are an important advance in the treatment of these children. Nevertheless, the hope is put in the new drugs directed to molecular targets of neuroblastoma. Anti-angiogenic drugs, ALK antagonist and PI3K/Akt/mTOR inhibitors are among the most promising.

Escalating topotecan in combination with treosulfan has acceptable toxicity in advanced pediatric sarcomas

Patients with advanced pediatric sarcomas have a poor prognosis and novel combination therapies are needed to improve the response rates. Hematological and organ related toxicities have been observed when administering topotecan in combination with, e.g., high dose thiotepa. This study evaluates the toxicity of escalating doses of topotecan alone or in combination with thiotepa or treosulfan. We compared the toxicity including death of complication (DOC) of topotecan alone or in combination with thiotepa or treosulfan in advanced pediatric sarcomas (n = 12). Ten of 12 patients (0.83) suffered from advanced tumors of the Ewing family (i.e., bone or marrow metastases or relapse <24 month after diagnosis, including one neuroepithelial tumor of the kidney) and two from alveolar rhabdomyosarcoma stage IV (0.17). Median age was 15 years (range 5-28). Ratio of female to male was 1:1. Two patients received topotecan alone (1.25 mg/m(2) q 5d and 1.5 mg/m(2) q 5d), three patients received four courses of topotecan (2 mg/m(2) q d 1-5) in combination with thiotepa (100 mg/m(2) q d 1-5), and seven patients received topotecan (2 mg/m(2) q d 1-5) in combination with treosulfan (10g/m(2) q d 3-5). Overall toxicity was not different between all three groups; mean scores were 1.6, 1.8, and 1.7 according to WHO grading (Scale 0-4). Organ related toxicity ranged between 0 and 4 and was not different as well. DOC was 0/2, 1/3, and 0/7 patients respectively. Escalating therapy with topotecan in combination with treosulfan has acceptable toxicity and warrants further investigation in advanced pediatric sarcomas.

Critical role of STAT3 in IL-6-mediated drug resistance in human neuroblastoma

Drug resistance is a major cause of treatment failure in cancer. Here, we have evaluated the role of STAT3 in environment-mediated drug resistance (EMDR) in human neuroblastoma. We determined that STAT3 was not constitutively active in most neuroblastoma cell lines but was rapidly activated upon treatment with interleukin (IL)-6 alone and in combination with the soluble IL-6 receptor (sIL-6R). Treatment of neuroblastoma cells with IL-6 protected them from drug-induced apoptosis in a STAT3-dependent manner because the protective effect of IL-6 was abrogated in the presence of a STAT3 inhibitor and upon STAT3 knockdown. STAT3 was necessary for the upregulation of several survival factors such as survivin (BIRC5) and Bcl-xL (BCL2L1) when cells were exposed to IL-6. Importantly, IL-6-mediated STAT3 activation was enhanced by sIL-6R produced by human monocytes, pointing to an important function of monocytes in promoting IL-6-mediated EMDR. Our data also point to the presence of reciprocal activation of STAT3 between tumor cells and bone marrow stromal cells including not only monocytes but also regulatory T cells (Treg) and nonmyeloid stromal cells. Thus, the data identify an IL-6/sIL-6R/STAT3 interactive pathway between neuroblastoma cells and their microenvironment that contributes to drug resistance.

Ten challenges in the management of neuroblastoma

Neuroblastoma is a complex disease with many contradictions and challenges. It is, by and large, a cancer of babies and preschool children, but it does occur, albeit increasingly rarely, in older children, adolescents and young adults. The prognosis is very variable, with outcome related to age, stage and molecular pathology. Neuroblastoma may behave in an almost benign way, with spontaneous regression in some infants, but the majority of older patients have high-risk disease, which is usually fatal, despite best current treatments. As a rare disease, international collaboration is essential to run clinical trials of adequate statistical power to answer important questions in a reasonable time frame. High-risk disease requires multimodality therapy including chemotherapy, surgery and radiotherapy as well as biological and immunological treatments for optimal outcomes. Innovative treatment approaches, sometimes associated with appreciable toxicity, offer hope for the future but, despite parental wishes, cannot be generally implemented without adequate assessment in clinical trials.

ABCC4/MRP4: a MYCN-regulated transporter and potential therapeutic target in neuroblastoma

Resistance to cytotoxic drugs is thought to be a major cause of treatment failure in childhood neuroblastoma, and members of the ATP-binding cassette (ABC) transporter superfamily may contribute to this phenomenon by active efflux of chemotherapeutic agents from cancer cells. As a member of the C subfamily of ABC transporters, multidrug resistance-associated protein MRP4/ABCC4 has the ability to export a variety of endogenous and exogenous substances across the plasma membrane. In light of its capacity for chemotherapeutic drug efflux, MRP4 has been studied in the context of drug resistance in a number of cancer cell types. However, MRP4 also influences cancer cell biology independently of chemotherapeutic drug exposure, which highlights the potential importance of endogenous MRP4 substrates in cancer biology. Furthermore, MRP4 is a direct transcriptional target of Myc family oncoproteins and expression of this transporter is a powerful independent predictor of clinical outcome in neuroblastoma. Together, these features suggest that inhibition of MRP4 may be an attractive therapeutic approach for neuroblastoma and other cancers that rely on MRP4. In this respect, existing options for MRP4 inhibition are relatively non-selective and thus development of more specific anti-MRP4 compounds should be a major focus of future work in this area.

5-day/5-drug myeloablative outpatient regimen for resistant neuroblastoma

5-day/5-drug (5D/5D) is a novel high-dose regimen administered with autologous hematopoietic SCT (HSCT). It was designed to maximize cytoreduction via high dosing of synergistically interacting agents, while minimizing morbidity in patients with resistant neuroblastoma (NB) and ineligible for clinical trials due to myelosuppression from previous therapy. 5D/5D comprises carboplatin 500 mg/m(2)/day on days 1-2, irinotecan 50 mg/m(2)/day on days 1-3, temozolomide 250 mg/m(2)/day on days 1-3, etoposide 200 mg/m(2)/day on days 3-5 and cyclophosphamide 70 mg/kg/day on days 4-5. HSCT is on day 8. Sixteen patients received 21 courses. Treatment was in the outpatient clinic. Responses were noted against progressive disease (PD) that had developed while patients were off, or receiving only low-dose, chemotherapy but not against PD that emerged despite high-dose chemotherapy. Responses were also seen in patients with PD or stable disease after (131)I-metaiodobenzylguanidine therapy. Grade 3 toxicities were limited to transient elevations in liver enzymes (three courses) and hyponatremia (one course). Bacteremia occurred in 2/21 (10%) courses. Hematological recovery allowed patients to be enrolled on clinical trials. In conclusion, 5D/5D (including HSCT) spares vital organs, entails modest morbidity, shows activity against resistant NB and helps patients meet eligibility requirements for formal clinical trials.

Resistance of neuroblastoma GI-ME-N cell line to glutathione depletion involves Nrf2 and heme oxygenase-1

Cancer cell survival is known to be related to the ability to counteract oxidative stress, and glutathione (GSH) depletion has been proposed as a mechanism to sensitize cells to anticancer therapy. However, we observed that GI-ME-N cells, a neuroblastoma cell line without MYCN amplification, are able to survive even if GSH-depleted by l-buthionine-(S,R)-sulfoximine (BSO). Here, we show that in GI-ME-N cells, BSO activates Nrf2 and up-regulates heme oxygenase-1 (HO-1). Silencing of Nrf2 restrained HO-1 induction by BSO. Inhibition of HO-1 and silencing of Nrf2 or HO-1 sensitized GI-ME-N cells to BSO, leading to reactive oxygen/nitrogen species overproduction and decreasing viability. Moreover, targeting the Nrf2/HO-1 axis sensitized GI-ME-N cells to etoposide more than GSH depletion. Therefore, we have provided evidence that in GI-ME-N cells, the Nrf2/HO-1 axis plays a crucial role as a protective factor against cellular stress, and we suggest that the inhibition of Nfr2/HO-1 signaling should be considered as a central target in the clinical battle against neuroblastoma.

Progress in treatment and risk stratification of neuroblastoma: impact on future clinical and basic research

Close international collaboration between pediatric oncologists has led to marked improvements in the cure of patients, seen as a long-term overall survival rate of about 80%. Despite this progress, neuroblastoma remains a challenging disease for both clinicians and researchers. Major clinical problems include lack of acceptable cure rates in high-risk neuroblastoma and potential overtreatment of subsets of patients at low and intermediate risk of the disease. Many years of intensive international cooperation have recently led to a promising joint effort to further improve risk classification for treatment stratification, the new International Neuroblastoma Risk Group Classification System. This approach will facilitate comparison of the results of clinical trials performed by different international collaborative groups. This, in turn, should accelerate refinement of risk stratification and thereby aid selection of appropriate therapies for individual patients. To be able to identify new therapeutic modalities, it will be necessary to elucidate the pathogenesis of the different subtypes of neuroblastoma. Basic and translational research have provided new tools for molecular characterization of blood and tumor samples including high-throughput technologies for analysis of DNA, mRNAs, microRNAs and other non-coding RNAs, as well as proteins and epigenetic markers. Most of these studies are array-based in design. In neuroblastoma research they aim to refine risk group stratification through incorporation of molecular tumor fingerprints and also to enable personalized treatment modalities by describing the underlying pathogenesis and aberrant signaling pathways in individual tumors. To make optimal use of these new technologies for the benefit of the patient, it is crucial to have a systematic and detailed documentation of both clinical and molecular data from diagnosis through treatment to follow-up. Close collaboration between clinicians and basic scientists will provide access to combined clinical and molecular data sets and will create more efficient steps in response to the remaining treatment challenges. This review describes the current efforts and trends in neuroblastoma research from a clinical perspective in order to highlight the urgent clinical problems we must address together with basic researchers.

Treatment and outcomes of patients with relapsed, high-risk neuroblastoma: results of German trials

BACKGROUND

The prognosis of high-risk neuroblastoma patients has improved over the last decades. However, many patients experience relapse after successful initial treatment. We retrospectively analyzed the long-term outcome of relapsed patients of three consecutive national neuroblastoma trials.

METHODS

Patients were included when they fulfilled all of the following criteria: Age at diagnosis being 1 year or older, first diagnosis between 1990 and 2007, stage 4 disease or stage 3 neuroblastoma with MYCN amplification, and relapse or progression after successful first-line autologous stem cell transplantation (ASCT).

RESULTS

A total of 451 high-risk neuroblastoma patients 1 year or older underwent ASCT during first-line treatment, 253 experienced recurrence of disease, 158 received salvage chemotherapy, and 23 of them finally underwent a second ASCT. These 23 patients had a better median survival (2.08 years) and 3-year survival rate from recurrence (43.5 ± 10.9%) compared to 74 patients who had no second chemotherapy (median survival 0.24 years, 3-year survival rate 4.0 ± 2.6%) and 135 patients who underwent second-line chemotherapy but did not undergo second ASCT (median survival of 0.89 years, 3-year survival rate 9.6 ± 2.8%, P < 0.001). By February 2010, 3/23 patients were in complete remission, 3/23 in very good partial remission, 1/23 in partial remission, 14/23 patients died of disease after successful second ASCT, and 2/23 died of complications due to second ASCT.

CONCLUSION

Intensive second-line therapy is feasible. A small subgroup of relapsed high-risk neuroblastoma patients may benefit from intensive relapse chemotherapy and second ASCT. The potential of long-term survival justifies clinical trials on intensive second-line treatment.

High-dose carboplatin-irinotecan-temozolomide: treatment option for neuroblastoma resistant to topotecan

BACKGROUND

We report a retrospective study of a novel regimen for neuroblastoma (NB) resistant to standard induction or salvage chemotherapy which now routinely includes topotecan.

PATIENTS AND METHODS

Forty-five patients received carboplatin (500 mg/m(2)/day, 2×)-irinotecan (50 mg/m(2)/day, 5×)-temozolomide (250 mg/m(2)/day, 5×) (HD-CIT). Only one course was planned. Patients with thrombocytopenia indicative of poor bone marrow (BM) reserve resulting from extensive prior therapy received peripheral blood stem cells (PBSCs) post-HD-CIT.

RESULTS

Modest acute toxicity allowed outpatient treatment. Low-grade diarrhea was common; there was no mucositis, nephrotoxicity, or cardiotoxicity. Myelosuppression was prolonged but uncomplicated. The absolute neutrophil count reached 500/µl on days 20-30 (median, 25) in 25 patients with satisfactory BM reserve, and on days 9-14 (median, 11) post-PBSC infusion. Anti-NB activity was common against refractory (non-progressing) disease or new relapse occurring off therapy (68% objective response rate), but not against disease progressing on therapy. Seven of 26 patients treated for refractory NB are progression-free and in complete remission following subsequent therapy, including anti-G(D2) immunotherapy, at ≥ 29+ months post-HD-CIT.

CONCLUSIONS

HD-CIT is appealing as salvage or consolidative therapy because of anti-NB activity and modest non-hematologic toxicity. PBSC support is unnecessary when BM reserve is intact. The wide antineoplastic activity of its three components and their potential for activity against disease in the central nervous system support applicability to other cancers.

PKCδ sensitizes neuroblastoma cells to L-buthionine-sulfoximine and etoposide inducing reactive oxygen species overproduction and DNA damage

Neuroblastoma is a type of pediatric cancer. The sensitivity of neuroblastoma (NB) cancer cells to chemotherapy and radiation is inhibited by the presence of antioxidants, such as glutathione (GSH), which is crucial in counteracting the endogenous production of reactive oxygen species (ROS). We have previously demonstrated that cells depleted of GSH undergo apoptosis via oxidative stress and Protein kinase C (PKC) δ activation. In the present study, we transfected PKCδ in NB cells resistant to oxidative death induced by L-buthionine-S,R-sulfoximine (BSO), a GSH-depleting agent. Cell responses, in terms of ROS production, apoptosis and DNA damage were evaluated. Moreover, PKCδ activation was monitored by analyzing the phosphorylation status of threonine 505 residue, carrying out PKC activity assay and investigating the subcellular localization of the kinase. The cell responses obtained in BSO-resistant cells were also compared with those obtained in BSO-sensitive cells subjected to the same experimental protocol. Our results demonstrate, for the first time, that PKCδ induces DNA oxidation and ROS overproduction leading to apoptosis of BSO-resistant NB cells and potentiates the cytotoxic effects induced by BSO in sensitive cells. Moreover, PKCδ overexpression enhances the sensitivity of NB cells to etoposide, a well-characterised drug, commonly used in neuroblastoma therapy. Altogether our data provide evidence of a pro-oxidant role of PKCδ that might be exploited to design new therapeutic strategies aimed at selective killing of cancer cells and overcoming drug resistance. However, it becomes evident that a more detailed understanding of ROS-mediated signaling in cancer cells is necessary for the development of redox-modulated therapeutic approaches.

Do pharmacokinetic polymorphisms explain treatment failure in high-risk patients with neuroblastoma?

PURPOSE

Neuroblastoma is the most common extracranial solid tumour in childhood. It accounts for 15% of all paediatric oncology deaths. In the last few decades, improvement in treatment outcome for high-risk patients has not occurred, with an overall survival rate <30-40%. Many reasons may account for such a low survival rate. The aim of this review is to evaluate whether pharmacogenetic factors can explain treatment failure in neuroblastoma.

METHODS

A literature search based on PubMed's database Medical Subject Headings (MeSH) was performed to retrieve all pertinent publications on current treatment options and new classes of drugs under investigation. One hundred and fifty-eight articles wer reviewed, and relevant data were extracted and summarised.

RESULTS AND CONCLUSIONS

Few of the large number of polymorphisms identified thus far showed an effect on pharmacokinetics that could be considered clinically relevant. Despite their clinical relevance, none of the single nucleotide polymorphisms (SNPs) investigated can explain treatment failure. These findings seem to reflect the clinical context in which anti-tumour drugs are used, i.e. in combination with multimodal therapy. In addition, many pharmacogenetic studies did not assess (differences in) drug exposure, which could contribute to explaining pharmacogenetic associations. Furthermore, it remains unclear whether the significant activity of new drugs on different neuroblastoma cell lines translates into clinical efficacy, irrespective of resistance or myelocytomatosis viral related oncogene, neuroblastoma derived (MYCN) amplification. Elucidation of the clinical role of pharmacogenetic factors in the treatment of neuroblastoma demands an integrated pharmacokinetic-pharmacodynamic approach to the analysis of treatment response data.

Short topotecan-based induction regimen in newly diagnosed high-risk neuroblastoma

PURPOSE

Topotecan is an active drug in relapsed neuroblastoma. We investigated the efficacy and toxicity of a topotecan-based induction regimen in newly diagnosed neuroblastoma.

METHODS

Patients older than 1 year with either metastatic or localised stage 2-3 MYCN-amplified neuroblastoma received 2 courses of high-dose topotecan (HD-TPT) 6mg/m(2) and high-dose cyclophosphamide (HD-CPM) 140 mg/kg, followed by 2 courses of ifosfamide, carboplatin and etoposide (ICE) every 28 days. After surgery on primary tumour, a fifth course with vincristine, doxorubicin and CPM was given, followed by high-dose chemotherapy with stem cell support. Response was assessed in accordance with the International Neuroblastoma Response Criteria.

RESULTS

Of 35 consecutive patients, 33 had metastatic disease. The median length of induction phase was 133 days (range 91-207) and time to high-dose chemotherapy was 208 days (range 156-285). The median tumour volume reduction was 55% after two HD-TPT/HD-CPM courses and 80% after four courses. Radical surgery was performed in 16/27 patients after chemotherapy. After the fifth course, 29/34 patients (85%) had achieved a partial remission (12) or a CR/very good partial remission (17). CR of metastases was achieved in 13/32 (41%) and bone marrow was in complete remission in 16/24 patients (67%). Grade 4 neutropenia and/or thrombocytopenia occurred in 100% of HD-TPT/HD-CPM and in 95% of ICE courses, while non-haematological toxicities were manageable.

CONCLUSIONS

These data indicate that our induction regimen is feasible and well tolerated. A major response rate of 85% with 41% complete metastatic response confirms this regimen as effective induction in high-risk neuroblastoma.

High-dose cyclophosphamide-irinotecan-vincristine for primary refractory neuroblastoma

BACKGROUND

We used a novel regimen for neuroblastoma (NB) that had responded inadequately to standard chemotherapy which now includes topotecan in induction or second-line therapy.

PATIENTS AND METHODS

We retrospectively studied 38 patients who received one or two courses of high-dose cyclophosphamide (140 mg/kg)-irinotecan (CPT-11) (250 mg/m(2))-vincristine (HD-CCV) as treatment for NB that had responded incompletely to induction but had never progressed. Treatment was outpatient and was preceded and followed by extent-of-disease and toxicity evaluations because the patients were being considered for enrolment on formal protocols. Progression-free survival (PFS) was calculated from day 1 of HD-CCV.

RESULTS

Common toxicities were grade 4 myelosuppression and grade 2 diarrhoea. Responses--5 complete (CR), 3 partial (PR), 4 mixed (MR)--occurred in 12/28 (43%) patients treated ≤9 months, and in 1/10 (10%) patients treated >10 months, from diagnosis. HD-CCV was the initial salvage regimen after topotecan-containing induction in 5 patients, achieving 1 CR, 1 MR and 3 stable disease (NR). HD-CCV produced responses (2 PR, 3 MR) in all 5 patients previously treated with CPT-11/ temozolomide. In contrast, all 6 patients treated post-HD-CCV with CPT-11/temozolomide had NR to the latter. Post-HD-CCV treatments included immunotherapy, targeted radiotherapy and/or chemotherapy. PFS was 64% (±8%) at 24 months, with 20 patients progression-free at 2+-to-36+ (median 16+) months and 10 in first CR at 9+-to-36+ (median 16+) months.

CONCLUSIONS

HD-CCV offers a treatment option against topotecan-resistant NB. Results support the concept that combining CPT-11 with very high doses of alkylators can yield greater antitumour effect.