Response, survival, and toxicity after iodine-131-metaiodobenzylguanidine therapy for neuroblastoma in preadolescents, adolescents, and adults

Adolescent- and adult-onset neuroblastic tumor: A retrospective multicenter observational study of patients diagnosed in France between 2000 and 2020

BACKGROUND

Adult- and adolescent-onset neuroblastomas are rare, with no established therapy. In addition, rare pheochromocytomas may harbor neuroblastic components. This study was designed to collect epidemiological, diagnostic and therapeutic data in order to better define the characteristics of malignant peripheral neuroblastic tumors (MPNT) and composite pheochromocytomas (CP) with MPNT.

PROCEDURE

Fifty-nine adults and adolescents (aged over 15 years) diagnosed with a peripheral or composite neuroblastic tumor, who were treated in one of 17 institutions between 2000 and 2020, were retrospectively studied.

RESULTS

Eighteen patients with neuroblastoma (NB) or ganglioneuroblastoma (GNB) had locoregional disease, and 28 patients had metastatic stage 4 NB. Among the 13 patients with CP, 12 had locoregional disease. Fifty-eight percent of the population were adolescents and young adults under 24 years of age. The probability of 5-year event-free survival (EFS) was 40% (confidence interval: 27%-53%).

CONCLUSIONS

Outcomes were better for patients with localized tumor than for patients with metastases. For patients with localized tumor, in terms of survival, surgical treatment was the best therapeutic option. Multimodal treatment with chemotherapy, surgery, radiotherapy, and immunotherapy-based maintenance allowed long-term survival for some patients. Adolescent- and adult-onset neuroblastoma appeared to have specific characteristics associated with poorer outcomes compared to pediatric neuroblastoma. Nevertheless, complete disease control improved survival. The presence of a neuroblastic component in pheochromocytoma should be considered when making therapeutic management decisions. The development of specific tools/resources (Tumor Referral Board, Registry, biology, and trials with new agents or strategies) may help to improve outcomes for patients.

Navigating new horizons: Prospects of NET-targeted radiopharmaceuticals in precision medicine

In the evolving landscape of precision medicine, NET-targeted radiopharmaceuticals are emerging as pivotal tools for the diagnosis and treatment of a range of conditions, from heart failure and neurodegenerative disorders to neuroendocrine cancers. This review evaluates the advancements offered by 18F-labeled PET tracers and 211At alpha-particle therapy, juxtaposed with current 123I-MIBG SPECT and 131I-MIBG therapies. The enhanced spatial resolution and capability for quantitative analysis render 18F-labeled PET tracers potential candidates for improved detection and management of diseases. Alpha-particle therapy with 211At may offer increased specificity and tumoricidal efficacy, pointing towards a shift in therapeutic protocols. While preliminary data is promising, these innovative approaches require thorough validation against current modalities. Ongoing clinical trials are pivotal to confirm the expected clinical benefits and to address safety concerns. This review underscores the need for rigorous research to verify the clinical utility of NET-targeted radiopharmaceuticals, which may redefine precision medicine paradigms and significantly impact patient care.

Reaching the target dose with one single 131 I-mIBG administration in high-risk neuroblastoma: The determinant impact of the primary tumour

BACKGROUND

131 I-metaiodobenzylguanidine (131 I-mIBG) effectiveness in children with metastasised neuroblastoma (NB) is linked to the effective dose absorbed by the target; a target of 4 Gy whole-body dose threshold has been proposed. Achieving this dose often requires administering 131 I-mIBG twice back-to-back, which may cause haematological toxicity. In this study, we tried identifying the factors predicting the achievement of 4 Gy whole-body dose with a single radiopharmaceutical administration.

MATERIALS AND METHODS

Children affected by metastatic NB and treated with a high 131 I-mIBG activity (>450 MBq (megabecquerel)/kg) were evaluated retrospectively. Kinetics measurements were carried out at multiple time points to estimate the whole-body dose, which was compared with clinical and activity-related parameters.

RESULTS

Seventeen children (12 females, median age 3 years, age range: 1.5-6.9 years) were included. Eleven of them still bore the primary tumour. The median whole-body dose was 2.88 Gy (range: 1.63-4.22 Gy). Children with a 'bulky' primary (>30 mL) received a higher whole-body dose than those with smaller or surgically removed primaries (3.42 ± 0.74 vs. 2.48 ± 0.65 Gy, respectively, p = .016). Conversely, the correlation between activity/kg and the whole-body dose was moderate (R: 0.42, p = .093). In the multivariate analysis, the volume of the primary tumour was the most relevant predictor of the whole-body dose (p = .002).

CONCLUSIONS

These data suggest that the presence of a bulky primary tumour can significantly prolong the 131 I-mIBG biological half-life, effectively increasing the absorbed whole-body dose. This information could be used to model the administered activity, allowing to attain the target dose without needing a two-step radiopharmaceutical administration.

Biodistribution and radiation dosimetry of 124I-mIBG in adult patients with neural crest tumours and extrapolation to paediatric models

AIM

Positron emission tomography (PET) using 124I-mIBG has been established for imaging and pretherapeutic dosimetry. Here, we report the first systematic analysis of the biodistribution and radiation dosimetry of 124I-mIBG in patients with neural crest tumours and project the results to paediatric patient models.

METHODS

Adult patients with neural crest tumours who underwent sequential 124I-mIBG PET were included in this retrospective single-center analysis. PET data were acquired 4, 24, 48, and/or 120 h after administration of a mean of 43 MBq 124I-mIBG. Whole-body counting and blood sampling were performed at 2, 4, 24, 48 and 120 h after administration. Absorbed organ dose and effective dose coefficients were estimated in OLINDA/EXM 2.2 according to the MIRD formalism. Extrapolation to paediatric models was performed based on mass-fraction scaling of the organ-specific residence times. Biodistribution data for adults were also projected to 123I-mIBG and 131I-mIBG.

RESULTS

Twenty-one patients (11 females, 10 males) were evaluated. For adults, the organs exposed to the highest dose per unit administered activity were urinary bladder (1.54 ± 0.40 mGy/MBq), salivary glands (0.77 ± 0.28 mGy/MBq) and liver (0.65 ± 0.22 mGy/MBq). Mean effective dose coefficient for adults was 0.25 ± 0.04 mSv/MBq (male: 0.24 ± 0.03 mSv/MBq, female: 0.26 ± 0.06 mSv/MBq), and increased gradually to 0.29, 0.44, 0.69, 1.21, and 2.94 mSv/MBq for the 15-, 10-, 5-, 1-years-old, and newborn paediatric reference patients. Projected mean effective dose coefficients for 123I-mIBG and 131I-mIBG for adults were 0.014 ± 0.002 mSv/MBq and 0.18 ± 0.04 mSv/MBq, respectively.

CONCLUSION

PET-based derived radiation dosimetry data for 124I-mIBG from this study agreed well with historical projected data from ICRP 53. The effective dose coefficients presented here may aid in guidance for establishing weight-based activity administration protocols.

Norepinephrine transporter and vesicular monoamine transporter 2 tumor expression as a predictor of response to 131 I-MIBG in patients with relapsed/refractory neuroblastoma

BACKGROUND

Prior studies suggest that norepinephrine transporter (NET) and vesicular monoamine transporter 2 (VMAT2) mediate meta-iodobenzylguanidine (MIBG) uptake and retention in neuroblastoma tumors. We evaluated the relationship between NET and VMAT2 tumor expression and clinical response to 131 I-MIBG therapy in patients with neuroblastoma.

METHODS

Immunohistochemistry (IHC) was used to evaluate NET and VMAT2 protein expression levels on archival tumor samples (obtained at diagnosis or relapse) from patients with relapsed or refractory neuroblastoma treated with 131 I-MIBG. A composite protein expression H-score was determined by multiplying a semi-quantitative intensity value (0-3+) by the percentage of tumor cells expressing the protein.

RESULTS

Tumor samples and clinical data were available for 106 patients, of whom 28.3% had partial response (PR) or higher. NET H-score was not significantly associated with response (≥PR), though the percentage of tumor cells expressing NET was lower among responders (median 80% for ≥PR vs. 90% for

CONCLUSIONS

Markers of lower NET and VMAT2 protein expression are associated with higher likelihood of response to 131 I-MIBG therapy in patients with relapsed/refractory neuroblastoma. Increased VMAT2 protein expression is associated with a more differentiated disease phenotype.

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Key Words

• 131I-MIBG
• biomarker
• neuroblastoma
• norepinephrine transporter
• vesicular monoamine transporter 2

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MESH Headings

• Humans
• 3-Iodobenzylguanidine/therapeutic use
• Norepinephrine Plasma Membrane Transport Proteins/metabolism
• Vesicular Monoamine Transport Proteins/metabolism
• Radiopharmaceuticals
• N-Myc Proto-Oncogene Protein
• Neoplasm Recurrence, Local/drug therapy
• Neuroblastoma/drug therapy
• Chronic Disease

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Grants

• R01 CA172067 NCI NIH HHS
• R35 CA220500 NCI NIH HHS
• R01 CA172067 NIH HHS
• R35 CA220500 NIH HHS

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Affiliation(s)

Vandana Batra Children’s Hospital of Philadelphia and Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA
Ajami Gikandi Harvard Medical School, Boston, MA
Bruce Pawel Department of Pathology, Children’s Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA
Daniel Martinez Children’s Hospital of Philadelphia and Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA
M. Meaghan Granger Department of Pediatrics, Cook Children’s Hospital, Fort Worth, TX
Araz Marachelian Department of Pediatrics, Children’s Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA
Julie R. Park Department of Pediatrics, Seattle Children’s Hospital and University of Washington School of Medicine, Seattle, WA
John M. Maris Children’s Hospital of Philadelphia and Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA
Kieuhoa T. Vo Department of Pediatrics, UCSF Benioff Children’s Hospital and UCSF School of Medicine, San Francisco, CA
Katherine K. Matthay Department of Pediatrics, UCSF Benioff Children’s Hospital and UCSF School of Medicine, San Francisco, CA
Steven G. DuBois Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, Harvard Medical School, Boston, MA

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Timing and chemotherapy association for 131-I-MIBG treatment in high-risk neuroblastoma

Prognosis of high-risk neuroblastoma is dismal, despite intensive induction chemotherapy, surgery, high-dose chemotherapy, radiotherapy, and maintenance. Patients who do not achieve a complete metastatic response, with clearance of bone marrow and skeletal NB infiltration, after induction have a significantly lowersurvival rate. Thus, it's necessary to further intensifytreatment during this phase. 131-I-metaiodobenzylguanidine (131-I-MIBG) is a radioactive compound highly effective against neuroblastoma, with32% response rate in relapsed/resistant cases, and only hematological toxicity. 131-I-MIBG wasutilized at different doses in single or multiple administrations, before autologous transplant or combinedwith high-dose chemotherapy. Subsequently, it was added to consolidationin patients with advanced NB after induction, but an independent contribution against neuroblastoma and for myelotoxicity is difficult to determine. Despiteresults of a 2008 paper demonstratedefficacy and mild hematological toxicity of 131-I-MIBG at diagnosis, no center had included it with intensive chemotherapy in first-line treatment protocols. In our institution, at diagnosis, 131-I-MIBG was included in a 5-chemotherapy drug combination and administered on day-10, at doses up to 18.3 mCi/kg. Almost 87% of objective responses were observed 50 days from start with acceptable hematological toxicity. In this paper, we review the literature data regarding 131-I-MIBG treatment for neuroblastoma, and report on doses and combinations used, tumor responses and toxicity. 131-I-MIBG is very effective against neuroblastoma, in particular if given to patients at diagnosis and in combination with chemotherapy, and it should be included in all induction regimens to improve early responses rates and consequently long-term survival.

SPECT/CT, PET/CT and PET/MRI: oncologic and infectious applications and protocol considerations

Functional imaging is playing an increasingly important role in pediatric radiology. Hybrid imaging techniques utilizing PET/CT (positron emission tomography/computed tomography), PET/MRI (positron emission tomography/magnetic resonance imaging), or SPECT/CT (single photon emission computed tomography/computed tomography) are now available in nearly every clinical practice. There are an increasing number of indications for the use of functional imaging, including oncologic and infectious indications, and it is essential to select and design the hybrid imaging protocol in order to optimize both the functional and anatomic components of the examination. Optimizing the protocol includes strategies for dose reduction, judicious use of contrast media and diagnostic quality imaging as appropriate, and for the greatest reduction in exposure to ionizing radiation, utilizing PET/MRI, whenever available. This review will provide an overview of hybrid imaging protocol considerations with a focus on oncologic and infectious indications.

The efficacy and safety of Iodine-131-metaiodobenzylguanidine therapy in patients with neuroblastoma: a meta-analysis

Objective

Neuroblastoma is a common extracranial solid tumor of childhood. Recently, multiple treatments have been practiced including Iodine-131-metaiodobenzylguanidine radiation (¹³¹I-MIBG) therapy. However, the outcomes of efficacy and safety vary greatly among different studies. The aim of this meta-analysis is to evaluate the efficacy and safety of ¹³¹I-MIBG in the treatment of neuroblastoma and to provide evidence and hints for clinical decision-making.

Methods

Medline, EMBASE database and the Cochrane Library were searched for relevant studies. Eligible studies utilizing ¹³¹I-MIBG in the treatment of neuroblastoma were included. The pooled outcomes (response rates, adverse events rates, survival rates) were calculated using either a random-effects model or a fixed-effects model considering of the heterogeneity.

Results

A total of 26 clinical trials including 883 patients were analyzed. The pooled rates of objective response, stable disease, progressive disease, and minor response of ¹³¹I-MIBG monotherapy were 39%, 31%, 22% and 15%, respectively. The pooled objective response rate of ¹³¹I-MIBG in combination with other therapies was 28%. The pooled 1-year survival and 5-year survival rates were 64% and 32%. The pooled occurrence rates of thrombocytopenia and neutropenia in MIBG monotherapy studies were 53% and 58%. In the studies of ¹³¹I-MIBG combined with other therapies, the pooled occurrence rates of thrombocytopenia and neutropenia were 79% and 78%.

Conclusion

¹³¹I-MIBG treatment alone or in combination of other therapies is effective on clinical outcomes in the treatment of neuroblastoma, individualized ¹³¹I-MIBG is recommended on a clinical basis.

Applications and prospects of targeted therapy for neuroblastoma

Background

Neuroblastoma is an extremely malignant tumor in children. For advanced or recurrent cases, existing treatment modalities are limited and efficacy remains disappointing. With the improvement in understanding of molecular biology of neuroblastoma and the development of clinical trials of targeted drug therapy, a variety of targeted therapies for neuroblastoma have appeared.

Data sources

All the recent literatures on targeted therapies of neuroblastoma on PubMed were searched and reviewed.

Results

This article reviewed targeted therapies of neuroblastoma going through clinical trials and obtained preliminary results. The features, advantages and disadvantages of targeted radiation therapy,

immunotherapy, gene and pathway molecular inhibitor and angiogenesis inhibitor were discussed.

Conclusion

This study provides references for better understanding the current progress of targeted therapies for neuroblastoma.

Norepinephrine-Transporter-Targeted and DNA-Co-Targeted Theranostic Guanidines

High risk neuroblastoma often recurs, even with aggressive treatments. Clinical evidence suggests that proliferative activities are predictive of poor outcomes. This report describes syntheses, characterization, and biological properties of theranostic guanidines that target norepinephrine transporter and undergo intracellular processing, and subsequently their catabolites are efficiently incorporated into DNA of proliferating neuroblastoma cells. Radioactive guanidines are synthesized from 5-radioiodo-2'-deoxyuridine, a molecular radiotherapy platform with clinically proven minimal toxicities and DNA-targeting properties. The transport of radioactive guanidines into neuroblastoma cells is active as indicated by the competitive suppression of cellular uptake by meta-iodobenzylguanidine. The rate of intracellular processing and DNA uptake is influenced by the agent's catabolic stability and cell population doubling times. The radiotoxicity is directly proportional to DNA uptake and duration of exposure. Biodistribution of 5-[¹²⁵I]iodo-3'-O-(ε-guanidinohexanoyl)-2'-deoxyuridine in a mouse neuroblastoma model shows significant tumor retention of radioactivity. Neuroblastoma xenografts regress in response to the clinically achievable doses of this agent.

Radiolabeled (R)-(-)-5-iodo-3'-O-[2-(ε-guanidinohexanoyl)-2-phenylacetyl]-2'-deoxyuridine: A new theranostic for neuroblastoma

Neuroblastoma, the most common extracranial solid tumor in children, accounts for nearly 8% of childhood cancers in the United States. It is a disease with pronounced clinical and biological heterogeneities. The amplification of MYCN, whose key tumorigenic functions include the promotion of proliferation, facilitation of the cell's entry into the S phase, and prevention of cells from leaving the cell cycle, correlates with poor prognosis. Patients with a high proliferation index disease have low survival rates. Neuroblastoma is one of the most radioresponsive of all human tumors. To exploit this radiosensitivity, radioactive guanidine (R)-(-)-5-[125 I]iodo-3'-O-[2-(ε-guanidinohexanoyl)-2-phenylacetyl]-2'-deoxyuridine (9, GPAID) was designed. This compound enters neuroblastoma cells much like metaiodobenzylguanidine (MIBG). Additionally, it cotargets DNA of proliferating cells, an attribute especially advantageous in the treatment of MYCN-amplified tumors. GPAID was synthesized from the trimethylstannyl precursor with an average yield of >90% at the no-carrier-added specific activities. The norepinephrine transporter-aided delivery of GPAID to neuroblastoma cells was established in the competitive uptake studies with nonradioactive MIBG. The intracellular processing and DNA targeting properties were confirmed in the subcellular distribution experiments. Studies in a mouse model of neuroblastoma demonstrated the therapeutic potential of GPAID. The tin precursor of GPAID can be used to prepare compounds radiolabeled with single-photon emission computed tomography (SPECT)- and positron-emission tomography (PET)-compatible radionuclides. Accordingly, these reagents can function as theranostics useful in the individualized and comprehensive treatment strategies comprising treatment planning and the assessment of tumor responses as well as the targeted molecular radiotherapy employing treatment doses derived from the imaging data.

Predictors of survival in patients with high-risk neuroblastoma who failed tandem high-dose chemotherapy and autologous stem cell transplantation

OBJECTIVE

This study aims to explore prognostic factors for high-risk neuroblastoma patients with response failure to tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/auto-SCT).

METHODS

Survival outcomes were compared according to characteristics at initial diagnosis, at relapse/progression, and after relapse/progression in patients who experienced relapse/progression after tandem HDCT/auto-SCT from 2006 to 2018.

RESULTS

Forty-nine patients experienced relapse/progression after tandem HDCT/auto-SCT during the study period: 43 received salvage treatment and 30 underwent allogeneic SCT (allo-SCT) after reinduction treatment. Although all six patients who did not undergo salvage treatment died, 13 of the 43 patients who did remain alive. The 3-year probabilities of event-free survival (EFS) and overall survival (OS) from initial relapse/progression among the 49 patients were 14.4% ± 5.2% and 21.2% ± 6.4%, respectively. A higher neuron-specific enolase (NSE) level (>24 ng/mL) at relapse/progression was an independent prognostic factor for worse OS. Nine of 30 patients who underwent allo-SCT remain alive, and the 3-year probabilities of EFS and OS from allo-SCT were 16.5% ± 7.2% and 21.6% ± 8.3%, respectively. A higher NSE level and no incorporation of high-dose ¹³¹ I-metaiodobenzylguanidine (HD-MIBG) treatment into allo-SCT were independent prognostic factors for worse EFS and OS after allo-SCT.

CONCLUSION

The results suggest that a higher serum NSE level at relapse/progression is a predictor of worse prognosis in patients with response failure to tandem HDCT/auto-SCT, and that incorporation of HD-MIBG treatment into allo-SCT may improve outcomes.

Radiation Safety Aspects of Iodine-131 metaiodobenzylguanidine (131I mIBG) Therapy Program Startup

As a medical center without a pre-existing radiopharmaceutical therapy program, it was a daunting endeavor to implement a I metaiodobenzylguanidine (mIBG) high-dose treatment regimen. It took several years of planning with hospital administration, vendors, and Texas Department of Health Radiological Control regulators to establish a viable program. Effective communication between physicians, nursing, nuclear medicine, environmental services, maintenance, and other support staff is essential and paramount for the successful execution and continued sustainability of the mIBG therapy program. Besides providing an effective treatment for patients, an additional goal for the program is to keep radiation exposure As Low As Reasonably Achievable (ALARA) for staff and patient caregivers. As such, start-up presented many training, logistical, and radiation safety challenges. The location of the isolation room and shielding specifications were designed to keep radiation exposure to public access areas to less than 2 microsieverts per hour. Before the first patient was treated the policies and procedures for training, radiation safety, product quality control, and infusion process needed to be developed, tested, and approved by various committees. Furthermore, a similar process was required for developing room set-up, post therapy cleanup, and waste storage procedures. Throughout the maturation process of the program, the departments involved have found that our safety culture has continually improved by the re-enforcement of knowledge and lessons learned, as both the ancillary and treatment staff grew more confident in each other's ability during more patient treatments are performed. This article describes the process and lessons learned during the time leading up to the startup and early years of the mIBG therapy program.

MIBG (metaiodobenzylguanidine) theranostics in pediatric and adult malignancies

Metaiodobenzylguanidine, a guanithidine analog, labeled with ¹²³I and ¹³¹I, is used for imaging and therapy of neuroblastomas and various neural crest tumors like paragangliomas, pheochromocytomas, medullary cancer of thyroid and carcinoids since the past three to four decades. In this review article, we shall revisit metaiodobenzylguanidine as a radiopharmaceutical and its various applications in neural crest tumors.

Targeted Molecular Radiotherapy of Pediatric Solid Tumors Using a Radioiodinated Alkyl-Phospholipid Ether Analog

External-beam radiotherapy plays a critical role in the treatment of most pediatric solid tumors. Particularly in children, achieving an optimal therapeutic index to avoid damage to normal tissue is extremely important. Consequently, in metastatic disease, the utility of external-beam radiotherapy is limited. Molecular radiotherapy with tumor-targeted radionuclides may overcome some of these challenges, but to date there exists no single cancer-selective agent capable of treating various pediatric malignancies independently of their histopathologic origin. We tested the therapeutic potential of the clinical-grade alkyl-phospholipid ether analog CLR1404, 18-(p-iodophenyl)octadecyl phosphocholine, as a scaffold for tumor-targeted radiotherapy of pediatric malignancies. Methods: Uptake of CLR1404 by pediatric solid tumor cells was tested in vitro by flow cytometry and in vivo by PET/CT imaging and dosimetry. The therapeutic potential of ¹³¹I-CLR1404 was evaluated in xenograft models. Results: In vitro, fluorescent CLR1404-BODIPY showed significant selective uptake in a variety of pediatric cancer lines compared with normal controls. In vivo tumor-targeted uptake in mouse xenograft models using ¹²⁴I-CLR1404 was confirmed by imaging. Single-dose intravenous injection of ¹³¹I-CLR1404 significantly delayed tumor growth in all rodent pediatric xenograft models and extended animal survival while demonstrating a favorable side effect profile. Conclusion:¹³¹I-CLR1404 has the potential to become a tumor-targeted radiotherapeutic drug with broad applicability in pediatric oncology. Because ¹³¹I-CLR1404 has entered clinical trials in adults, our data warrant the development of pediatric clinical trials for this particularly vulnerable patient population.

Overview and recent advances in the treatment of neuroblastoma

INTRODUCTION

Children with neuroblastoma have widely divergent outcomes, ranging from cure in >90% of patients with low risk disease to <50% for those with high risk disease. Recent research has shed light on the biology of neuroblastoma, allowing for more accurate risk stratification and treatment reduction in many cases, although newer treatment strategies for children with high-risk and relapsed neuroblastoma are needed to improve outcomes. Areas covered: Neuroblastoma epidemiology, diagnosis, risk stratification, and recent advances in treatment of both newly diagnosed and relapsed neuroblastoma. Expert commentary: The identification of newer tumor targets and of novel cell-mediated immunotherapy agents may lead to novel therapeutic approaches, and clinical trials for regimens designed to target individual genetic aberrations in tumors are underway. A combination of therapeutic modalities will likely be required to improve survival and cure rates for patients with high-risk neuroblastoma.

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.

Different outcomes for relapsed versus refractory neuroblastoma after therapy with (131)I-metaiodobenzylguanidine ((131)I-MIBG)

BACKGROUND

(131)I-metaiodobenzylguanidine ((131)I-MIBG) is a targeted radiopharmaceutical with significant activity in high-risk relapsed and chemotherapy-refractory neuroblastoma. Our primary aim was to determine if there are differences in response rates to (131)I-MIBG between patients with relapsed and treatment-refractory neuroblastoma.

METHODS

This was a retrospective cohort analysis of 218 patients with refractory or relapsed neuroblastoma treated with (131)I-MIBG at UCSF between 1996 and 2014. Results were obtained by chart review and database abstraction. Baseline characteristics and response rates between relapsed patients and refractory patients were compared using Fisher exact and Wilcoxon rank sum tests, and differences in overall survival (OS) were compared using the log-rank test.

RESULTS

The response rate (complete and partial response) to (131)I-MIBG-based therapies for all patients was 27%. There was no difference in response rates between relapsed and refractory patients. However, after (131)I-MIBG, 24% of relapsed patients had progressive disease compared to only 9% of refractory patients, and 39% of relapsed patients had stable disease compared to 59% of refractory patients (p=0.02). Among all patients, the 24-month OS was 47.0% (95% confidence interval (CI) 39.9-53.9%). The 24-month OS for refractory patients was significantly higher at 65.3% (95% CI 51.8-75.9%), compared to 38.7% (95% CI 30.4-46.8%) for relapsed patients (p<0.001).

CONCLUSIONS

Although there was no significant difference in overall response rates to (131)I-MIBG between patients with relapsed versusrefractory neuroblastoma, patients with prior relapse had higher rates of progressive disease and had lower 2-year overall survival after (131)I-MIBG compared to patients with refractory disease.

Surgical resection and post-operative radiotherapy in an adult renal neuroblastoma patient with multiple bone and joint metastases: A case report

Renal neuroblastoma is uncommon, particularly in adults, with only a few cases having been reported in studies published in the English language. The incidence is only 0.12 cases/1 million individuals in those aged >20 years. Studies of the pathogenesis, biological characteristics, treatment and prognosis of renal neuroblastoma are limited due to this low incidence. The present study reports the case of a 22-year-old adult female who was diagnosed with a left renal neuroblastoma by computed tomography (CT), bone scan and pathological examination. The patient underwent a left nephroureterectomy, ipsilateral lymph node dissection and post-operative radiotherapy, prior to discharge 60 days after admittance. At the nine-month follow-up examination, the patient showed no evidence of recurrence, progression or metastatic disease on the CT scans of the chest, abdomen and pelvis. Renal neuroblastoma is extremely uncommon in adults. The diagnosis and treatment of renal neuroblastoma is complicated by the overall low incidence, lack of specific treatment guidelines, advanced disease state due to late presentation, and its associated co-morbidities. Further study of the pathogenesis, biological and clinical characteristics, and treatment of renal neuroblastoma is required to provide an optimal treatment for patients and to improve the patient's quality of life.

Neuroblastoma after childhood: prognostic relevance of segmental chromosome aberrations, ATRX protein status, and immune cell infiltration

Neuroblastoma (NB) is a common malignancy in children but rarely occurs during adolescence or adulthood. This subgroup is characterized by an indolent disease course, almost uniformly fatal, yet little is known about the biologic characteristics. The aim of this study was to identify differential features regarding DNA copy number alterations, α-thalassemia/mental retardation syndrome X-linked (ATRX) protein expression, and the presence of tumor-associated inflammatory cells. Thirty-one NB patients older than 10 years who were included in the Spanish NB Registry were considered for the current study; seven young and middle-aged adult patients (range 18-60 years) formed part of the cohort. We performed single nucleotide polymorphism arrays, immunohistochemistry for immune markers (CD4, CD8, CD20, CD11b, CD11c, and CD68), and ATRX protein expression. Assorted genetic profiles were found with a predominant presence of a segmental chromosome aberration (SCA) profile. Preadolescent and adolescent NB tumors showed a higher number of SCA, including 17q gain and 11q deletion. There was also a marked infiltration of immune cells, mainly high and heterogeneous, in young and middle-aged adult tumors. ATRX negative expression was present in the tumors. The characteristics of preadolescent, adolescent, young adult, and middle-aged adult NB tumors are different, not only from childhood NB tumors but also from each other. Similar examinations of a larger number of such tumor tissues from cooperative groups should lead to a better older age–dependent tumor pattern and to innovative, individual risk-adapted therapeutic approaches for these patients.

Nothing but NET: a review of norepinephrine transporter expression and efficacy of 131I-mIBG therapy

Neuroblastoma is unique amongst common pediatric cancers for its expression of the norepinephrine transporter (NET), enabling tumor-selective imaging and therapy with radioactive analogues of norepinephrine. The majority of neuroblastoma tumors are avid for (123)I-metaiodobenzaguanidine (mIBG) on imaging, yet the therapeutic response to (131) I-mIBG is only 30% in clinical trials, and off-target effects cause short- and long-term morbidity. We review the contemporary understanding of the tumor-selective uptake, retention, and efflux of meta-iodobenzylguanidine (mIBG) and strategies currently in development for improving its efficacy. Combination treatment strategies aimed at enhancing NET are likely necessary to reach the full potential of (131)I-mIBG therapy.

Treatment setting, clinical trial enrollment, and subsequent outcomes among adolescents with cancer: a literature review

BACKGROUND

There has been an overall improvement in survival rates for persons with cancer over the past 35 years. However, these gains are less prevalent among adolescents with cancer aged 15 to 19 years, which may be due to lower clinical trial enrollment among adolescents with cancer.

METHODS

We conducted a literature review to assess current research regarding clinical trial enrollment and subsequent outcomes among adolescents with cancer. The search included English-language publications that reported original data from January 1985 to October 2011.

RESULTS

The search identified 539 records. Of these 539 records, there were 30 relevant original research articles. Multiple studies reported that adolescents with cancer are enrolled in clinical trials at lower rates compared with younger children and older adults. Treatment setting, physician type, and institution type may all be factors in the low enrollment rate among adolescents. Few data focused solely on adolescents, with many studies combining adolescents with young adults. The number of available studies related to this topic was limited, with significant variability in study design, methods, and outcomes.

CONCLUSIONS

This literature review suggests that adolescents with cancer are not treated at optimal settings and are enrolled in clinical trials at low rates. This may lead to inferior treatment and poor subsequent medical and psychosocial outcomes. The scarcity in data further validates the need for additional research focusing on this population.

Neuroblastoma in older children, adolescents and young adults: a report from the International Neuroblastoma Risk Group project

BACKGROUND

Neuroblastoma in older children and adolescents has a distinctive, indolent phenotype, but little is known about the clinical and biological characteristics that distinguish this rare subgroup. Our goal was to determine if an optimal age cut-off exists that defines indolent disease and if accepted prognostic factors and treatment approaches are applicable to older children.

PROCEDURE

Using data from the International Neuroblastoma Risk Group, among patients ≥18 months old (n = 4,027), monthly age cut-offs were tested to determine the effect of age on survival. The prognostic effect of baseline characteristics and autologous hematopoietic cell transplant (AHCT) for advanced disease was assessed within two age cohorts; ≥5 to <10 years (n = 730) and ≥10 years (n = 200).

RESULTS

Older age was prognostic of poor survival, with outcome gradually worsening with increasing age at diagnosis, without statistical evidence for an optimal age cut-off beyond 18 months. Among patients ≥5 years, factors significantly prognostic of lower event-free survival (EFS) and overall survival (OS) in multivariable analyses were INSS stage 4, MYCN amplification and unfavorable INPC histology classification. Among stage 4 patients, AHCT provided a significant EFS and OS benefit. Following relapse, patients in both older cohorts had prolonged OS compared to those ≥18 months to <5 years (P < 0.0001).

CONCLUSIONS

Despite indolent disease and infrequent MYCN amplification, older children with advanced disease have poor survival, without evidence for a specific age cut-off. Our data suggest that AHCT may provide a survival benefit in older children with advanced disease. Novel therapeutic approaches are required to more effectively treat these patients.

A systematic review of 131I-meta iodobenzylguanidine molecular radiotherapy for neuroblastoma

The optimal use and effectiveness of (131)I-meta iodobenzylguanidine ((131)I-mIBG) molecular radiotherapy for neuroblastoma remain unclear despite extensive clinical experience. This systematic review aimed to improve understanding of the current data and define uncertainties for future clinical trials. Bibliographic databases were searched for neuroblastoma and (131)I-mIBG. Clinical trials and non-comparative case series of (131)I-mIBG therapy for neuroblastoma were included. Two reviewers assessed papers for inclusion using the title and abstract with consensus achieved by discussion. Data were extracted by one reviewer and checked by a second. Studies with multiple publications were reported as a single study. The searches yielded 1216 citations, of which 51 publications reporting 30 studies met our inclusion criteria. No randomised controlled trials (RCTs) were identified. In two studies (131)I-mIBG had been used as induction therapy and in one study it had been used as consolidation therapy. Twenty-seven studies for relapsed and refractory disease were identified. Publication dates ranged from 1987 to 2012. Total number of patients was 1121 with study sizes ranging from 10 to 164. There was a large amount of heterogeneity between the studies with regard to patient population, treatment schedule and response assessment. Study quality was highly variable. The objective tumour response rate reported in 25 studies ranged from 0% to 75%, mean 32%. We conclude that (131)I-mIBG is an active treatment for neuroblastoma, but its place in the management of neuroblastoma remains unclear. Prospective randomised trials are essential to strengthen the evidence base.

An overview of translational (radio)pharmaceutical research related to certain oncological and non-oncological applications

Translational medicine pursues the conversion of scientific discovery into human health improvement. It aims to establish strategies for diagnosis and treatment of diseases. Cancer treatment is difficult. Radio-pharmaceutical research has played an important role in multiple disciplines, particularly in translational oncology. Based on the natural phenomenon of necrosis avidity, OncoCiDia has emerged as a novel generic approach for treating solid malignancies. Under this systemic dual targeting strategy, a vascular disrupting agent first selectively causes massive tumor necrosis that is followed by iodine-131 labeled-hypericin (¹²³I-Hyp), a necrosis-avid compound that kills the residual cancer cells by crossfire effect of beta radiation. In this review, by emphasizing the potential clinical applicability of OncoCiDia, we summarize our research activities including optimization of radioiodinated hypericin Hyp preparations and recent studies on the biodistribution, dosimetry, pharmacokinetic and, chemical and radiochemical toxicities of the preparations. Myocardial infarction is a global health problem. Although cardiac scintigraphy using radioactive perfusion tracers is used in the assessment of myocardial viability, searching for diagnostic imaging agents with authentic necrosis avidity is pursued. Therefore, a comparative study on the biological profiles of the necrosis avid ¹²³I-Hyp and the commercially available ^99mTc-Sestamibi was conducted and the results are demonstrated. Cholelithiasis or gallstone disease may cause gallbladder inflammation, infection and other severe complications. While studying the mechanisms underlying the necrosis avidity of Hyp and derivatives, their naturally occurring fluorophore property was exploited for targeting cholesterol as a main component of gallstones. The usefulness of Hyp as an optical imaging agent for cholelithiasis was studied and the results are presented. Multiple uses of automatic contrast injectors may reduce costs and save resources. However, cross-contaminations with blood-borne pathogens of infectious diseases may occur. We developed a radioactive method for safety evaluation of a new replaceable patient-delivery system. By mimicking pathogens with a radiotracer, we assessed the feasibility of using the system repeatedly without septic risks. This overview is deemed to be interesting to those involved in the related fields for translational research.

Treatment with topotecan plus cyclophosphamide in children with first relapse of neuroblastoma

BACKGROUND

Reports of responses and toxicities of salvage therapies for relapsed neuroblastoma are rare and often confounded by effects of additional treatments. Our objective was to describe the outcomes and toxicities for a topotecan and cyclophosphamide (TOPO/CTX) regimen for first relapse or progression of high-risk neuroblastoma.

METHODS

We retrospectively reviewed charts of relapsed or refractory neuroblastoma patients treated between 1999 and 2009 with our standard-of-care outpatient TOPO/CTX (0.75 and 250 mg/m(2) /day × 5 days q3-4 weeks).

RESULTS

Twenty-seven patients received 343 cycles of TOPO/CTX (median 10 cycles per patient, range 1-32). Most patients (N = 25) had undergone autologous stem cell transplantation. Seventeen (63%) patients had an objective response (CR + PR + MR). The 3-year progression-free survival (PFS) after relapse was 11 ± 6% and 3-year overall survival (OS) after relapse was 33 ± 9%. The median PFS was 1.2 years and the median OS was 2.3 years. Five patients are alive with follow-up of 3.1-5.5 years. Shorter time from diagnosis to relapse (6-18 months) was associated with shorter OS. The majority of patients experienced chemotherapy delays, transfusions, and febrile neutropenia, including eight bacterial infections. The mean number of hospitalized days was less than one per cycle.

CONCLUSIONS

TOPO/CTX was well tolerated and resulted in response rates and PFS similar to those reported for patients treated on COG 9462. Our study provides additional toxicity, historical endpoints, and time-to-progression data against which new agents and combination therapies using TOPO/CTX as a backbone can be measured.

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.

Age dependence of tumor genetics in unfavorable neuroblastoma: arrayCGH profiles of 34 consecutive cases, using a Swedish 25-year neuroblastoma cohort for validation

Background

Aggressive neuroblastoma remains a significant cause of childhood cancer death despite current intensive multimodal treatment protocols. The purpose of the present work was to characterize the genetic and clinical diversity of such tumors by high resolution arrayCGH profiling.

Methods

Based on a 32K BAC whole-genome tiling path array and using 50-250K Affymetrix SNP array platforms for verification, DNA copy number profiles were generated for 34 consecutive high-risk or lethal outcome neuroblastomas. In addition, age and MYCN amplification (MNA) status were retrieved for 112 unfavorable neuroblastomas of the Swedish Childhood Cancer Registry, representing a 25-year neuroblastoma cohort of Sweden, here used for validation of the findings. Statistical tests used were: Fisher’s exact test, Bayes moderated t-test, independent samples t-test, and correlation analysis.

Results

MNA or segmental 11q loss (11q-) was found in 28/34 tumors. With two exceptions, these aberrations were mutually exclusive. Children with MNA tumors were diagnosed at significantly younger ages than those with 11q- tumors (mean: 27.4 vs. 69.5 months; p=0.008; n=14/12), and MNA tumors had significantly fewer segmental chromosomal aberrations (mean: 5.5 vs. 12.0; p<0.001). Furthermore, in the 11q- tumor group a positive correlation was seen between the number of segmental aberrations and the age at diagnosis (Pearson Correlation 0.606; p=0.037). Among nonMNA/non11q- tumors (n=6), one tumor displayed amplicons on 11q and 12q and three others bore evidence of progression from low-risk tumors due to retrospective evidence of disease six years before diagnosis, or due to tumor profiles with high proportions of numerical chromosomal aberrations. An early age at diagnosis of MNA neuroblastomas was verified by registry data, with an average of 29.2 months for 43 cases that were not included in the present study.

Conclusion

MNA and segmental 11q loss define two major genetic variants of unfavorable neuroblastoma with apparent differences in their pace of tumor evolution and in genomic integrity. Other possible, but less common, routes in the development of aggressive tumors are progression of low-risk infant-type lesions, and gene amplifications other than MYCN. Knowledge on such nosological diversity of aggressive neuroblastoma might influence future strategies for therapy.

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.

Neuroblastoma

Neuroblastoma is a heterogeneous disease; tumors can spontaneously regress or mature, or display an aggressive, therapy-resistant phenotype. Increasing evidence indicates that the biological and molecular features of neuroblastoma significantly influence and are highly predictive of clinical behavior. Because of this, neuroblastoma has served as a paradigm for biological risk assessment and treatment assignment. Most current clinical studies of neuroblastoma base therapy and its intensity on a risk stratification that takes into account both clinical and biological variables predictive of relapse. For example, surgery alone offers definitive therapy with excellent outcome for patients with low-risk disease, whereas patients at high risk for disease relapse are treated with intensive multimodality therapy. In this review recent advances in the understanding of the molecular genetic events involved in neuroblastoma pathogenesis are discussed, and how they are impacting the current risk stratification and providing potential targets for new therapeutic approaches for children with neuroblastoma. In addition, the results of significant recent clinical trials for the treatment of neuroblastoma are reviewed.