Systematic review of clinical drug development activities for neuroblastoma from 2011 to 2020

131I-mIBG therapy in relapsed/refractory neuroblastoma: an old bridge to the future

BACKGROUND

The prognosis of relapsed/refractory (R/R) neuroblastoma (NB) is still dismal. The role of iodine-131 meta-iodobenzylguanidine (131I-mIBG) treatment as a tool to reduce tumour burden before novel immunotherapies is not defined.

PATIENTS AND METHODS

Patients with R/R NB were included in a prospective observational study based on two infusions of 131I-mIBG plus melphalan (110 mg/m2), supported by autologous haematopoietic stem cell rescue. The activity of the first administration was 444 MBq (12 mCi/kg), while the second dose was modulated to reach a whole-body absorbed dose of 4 Gy. The International Neuroblastoma Response Criteria (INRC) were used for response.

RESULTS

Twenty-six patients with a median age of 5.9 years (range 2.5-17.2 years) were treated. Twenty-three patients presented a bone/bone marrow involvement, and 21 patients presented an uptake at primary site or at soft-tissue sites. The median International Society of Paediatric Oncology Europe Neuroblastoma Group (SIOPEN) skeletal score was 10 (range 1-70). The main recorded toxicities were haematological, with no toxic deaths and only one grade 4 mucositis. Hypothyroidism was reported in 6 patients of the 14 alive patients. The overall response rate was 48% [95% confidence interval (CI) 28% to 69%] with only one progression; after treatment the median SIOPEN skeletal score was 6 (range 0-70) with a median reduction of 35% (range 4.3%-100%). Overall, 52% (95% CI 32% to 73%) of patients achieved/maintained a SIOPEN skeletal score <7 and a soft-tissue lesion <5 cm was seen in 67% (95% CI 43% to 91%). After this treatment, 65% of patients underwent GD2-targeting chimeric antigen receptor (CAR)-T-cell therapy and 50%, high-dose chemotherapy with busulfan and melphalan. The 3-year overall survival was 55% (95% CI 33% to 73%) and event-free survival was 42% (95% CI 23% to 60%).

CONCLUSION

The 131I-mIBG therapy plus melphalan is confirmed to be effective to reduce/control tumour burden. Further studies are needed to clarify the role and timing of this treatment and to integrate its role in the strategy of CAR-T cells.

131I-mIBG therapy in relapsed/refractory neuroblastoma: A weapon from the future past

Neuroblastoma (NB) is the most common extracranial solid tumor in children, with variable outcomes ranging from spontaneous remission to high-risk cases often leading to relapse or refractory disease. Approximately 50 % of patients with NB have high-risk features, often experiencing relapse or refractory disease despite intensive treatments and the prognosis remains poor, with long-term event-free survival (EFS) rates below 10 %,Radioactive iodine-labeled meta-iodobenzylguanidine (¹³¹I-mIBG) therapy, leveraging NB cells' radiosensitivity and expression of the norepinephrine transporter (NET), has shown promise in treating relapsed or refractory NB. Since 1985, ¹³¹I-mIBG has been studied to determine the maximum tolerated dose and side effects, with recent trials exploring its use in front-line treatment. Our systematic review, based on MEDLINE, EMBASE, and Cochrane CENTRAL databases up to December 2023, evaluates the effectiveness and toxicity of ¹³¹I-mIBG therapy in relapsed/refractory NB. It also discusses its potential role in conjunction with emerging therapies like CAR-T cells, haploidentical stem cell transplantation, and dinutuximab beta.

Statistical Fragility of Findings From Randomized Phase 3 Trials in Pediatric Oncology

PURPOSE

The fragility index (FI) is an adjunctive metric to facilitate the interpretation of p-values in clinical trials. The FI has not been studied in phase 3 trials in pediatric oncology.

METHODS

PubMed was used to identify phase 3 pediatric oncology trials published between 1980 and 2020. We report trial characteristics and calculate the FI for trials with a binary outcome and survival-inferred fragility index (SIFI) for trials with a time-to-event outcome. FI/SIFI is the number of patients from one arm of a trial who would need to change groups for the statistical conclusion to change. We also report fragility quotients (FQ and SFQ) to normalize FI and SIFI relative to trial size.

RESULTS

One hundred and thirteen trials included sufficient data for analysis. The median FI for trials with a binary outcome (n = 40) was 4.5 (range: 1-33). The median SIFI for trials with a time-to-event outcome (n = 73) was 13 (range: 0-61). The FI or SIFI was less than the number of patients lost to follow-up in 25% of 36 trials. Median FQ and SFQ were 0.026 and 0.03, respectively, and did not significantly vary according to trial characteristics. While sample sizes increased over time, the FQ and SFQ remained stable.

CONCLUSIONS

The statistical conclusions of pediatric oncology phase 3 trials hinge on a relatively small number and proportion of patients. Despite the sample size limitations of low prevalence diseases, pediatric cancer trials are similarly or less fragile than adult oncology trials. Smaller trials do not appear more statistically fragile than larger trials. Statistical fragility appears to have remained constant over the four decades evaluated. We recommend reporting FI or SIFI, in conjunction with p-values, for all phase 3 pediatric oncology trials.

Opaganib Downregulates N-Myc Expression and Suppresses In Vitro and In Vivo Growth of Neuroblastoma Cells

Neuroblastoma (NB), the most common cancer in infants and the most common solid tumor outside the brain in children, grows aggressively and responds poorly to current therapies. We have identified a new drug (opaganib, also known as ABC294640) that modulates sphingolipid metabolism by inhibiting the synthesis of sphingosine 1-phosphate (S1P) by sphingosine kinase-2 and elevating dihydroceramides by inhibition of dihydroceramide desaturase. The present studies sought to determine the potential therapeutic activity of opaganib in cell culture and xenograft models of NB. Cytotoxicity assays demonstrated that NB cells, including cells with amplified MYCN, are effectively killed by opaganib concentrations well below those that accumulate in tumors in vivo. Opaganib was shown to cause dose-dependent decreases in S1P and hexosylceramide levels in Neuro-2a cells, while concurrently elevating levels of dihydroceramides. As with other tumor cells, opaganib reduced c-Myc and Mcl-1 protein levels in Neuro-2a cells, and also reduced the expression of the N-Myc protein. The in vivo growth of xenografts of human SK-N-(BE)2 cells with amplified MYCN was suppressed by oral administration of opaganib at doses that are well tolerated in mice. Combining opaganib with temozolomide plus irinotecan, considered the backbone for therapy of relapsed or refractory NB, resulted in increased antitumor activity in vivo compared with temozolomide plus irinotecan or opaganib alone. Mice did not lose additional weight when opaganib was combined with temozolomide plus irinotecan, indicating that the combination is well tolerated. Opaganib has additive antitumor activity toward Neuro-2a tumors when combined with the checkpoint inhibitor anti-CTLA-4 antibody; however, the combination of opaganib with anti-PD-1 or anti-PD-L1 antibodies did not provide increased antitumor activity over that seen with opaganib alone. Overall, the data demonstrate that opaganib modulates sphingolipid metabolism and intracellular signaling in NB cells and inhibits NB tumor growth alone and in combination with other anticancer drugs. Amplified MYCN does not confer resistance to opaganib, and, in fact, the drug attenuates the expression of both c-Myc and N-Myc. The safety of opaganib has been established in clinical trials with adults with advanced cancer or severe COVID-19, and so opaganib has excellent potential for treating patients with NB, particularly in combination with temozolomide and irinotecan or anti-CTLA-4 antibody.

Functionalized GD2 Electrochemical Immunosensor to Diagnose Minimum Residual Disease of Bone Marrow in Neuroblastoma Effectively

Neuroblastoma (NB) is known as the "king of childhood tumors" due to its highly metastatic, recurrence-prone, and difficult-to-treat characteristics. International Neuroblastoma Risk Grading Group (INRG) has recommended GD2, a disialoganglioside expressed on neuroectodermal tumor cells, as the target for detecting minimal residual disease in bone marrow metastases of high-risk neuroblastoma in children. Therefore, accurately identifying GD2-positive cells is crucial for diagnosing children with high-risk NB. Here, we designed a graphene/AuNP/GD2 Ab-functionalized electrochemical biosensor for GD2 detection. A three-electrode system was processed using a screen-printed technique with a working electrode of indium tin oxide, a counter electrode of carbon, and a reference electrode of silver/silver chloride. Graphene/AuNPs were modified on the indium tin oxide electrode using chronoamperometric scans, and then, the GD2 antibody was modified on the biosensor by electrostatic adsorption to achieve sensitive and specific detection of GD2-positive cells in bone marrow fluid. The results showed that a graphene/AuNP/GD2 Ab-functionalized electrochemical biosensor achieved GD2-positive cell detection in the range of 102 cells/mL~105 cells/mL by differential pulse voltammetry. Bone marrow fluid samples from 12 children with high-risk NB were retained for testing on our biosensor and showed 100% compliance with the clinical application of the gold-standard immunocytochemical staining technique for detecting GD2-positive cells qualitatively. The GD2-based electrochemical assay can accurately detect children with high-risk NB, providing a rapidly quantitative basis for clinical diagnosis and treatment.

Target Genes of c-MYC and MYCN with Prognostic Power in Neuroblastoma Exhibit Different Expressions during Sympathoadrenal Development

Deregulation of the MYC family of transcription factors c-MYC (encoded by MYC), MYCN, and MYCL is prevalent in most human cancers, with an impact on tumor initiation and progression, as well as response to therapy. In neuroblastoma (NB), amplification of the MYCN oncogene and over-expression of MYC characterize approximately 40% and 10% of all high-risk NB cases, respectively. However, the mechanism and stage of neural crest development in which MYCN and c-MYC contribute to the onset and/or progression of NB are not yet fully understood. Here, we hypothesized that subtle differences in the expression of MYCN and/or c-MYC targets could more accurately stratify NB patients in different risk groups rather than using the expression of either MYC gene alone. We employed an integrative approach using the transcriptome of 498 NB patients from the SEQC cohort and previously defined c-MYC and MYCN target genes to model a multigene transcriptional risk score. Our findings demonstrate that defined sets of c-MYC and MYCN targets with significant prognostic value, effectively stratify NB patients into different groups with varying overall survival probabilities. In particular, patients exhibiting a high-risk signature score present unfavorable clinical parameters, including increased clinical risk, higher INSS stage, MYCN amplification, and disease progression. Notably, target genes with prognostic value differ between c-MYC and MYCN, exhibiting distinct expression patterns in the developing sympathoadrenal system. Genes associated with poor outcomes are mainly found in sympathoblasts rather than in chromaffin cells during the sympathoadrenal development.