Managing Adverse Events Associated with Dinutuximab Beta Treatment in Patients with High-Risk Neuroblastoma: Practical Guidance

Desensitizing the autonomic nervous system to mitigate anti-GD2 monoclonal antibody side effects

Background

Anti-GD2 monoclonal antibodies (mAbs) have shown to improve the overall survival of patients with high-risk neuroblastoma (HR-NB). Serious adverse events (AEs), including pain, within hours of antibody infusion, have limited the development of these therapies. In this study, we provide evidence of Autonomic Nervous System (ANS) activation as the mechanism to explain the main side effects of anti-GD2 mAbs.

Methods

Through confocal microscopy and computational super-resolution microscopy experiments we explored GD2 expression in postnatal nerves of infants. In patients we assessed the ANS using the Sympathetic Skin Response (SSR) test. To exploit tachyphylaxis, a novel infusion protocol (the Step-Up) was mathematically modelled and tested.

Results

Through confocal microscopy, GD2 expression is clearly visible in the perineurium surrounding the nuclei of nerve cells. By computational super-resolution microscopy experiments we showed the selective expression of GD2 on the cell membranes of human Schwann cells in peripheral nerves (PNs) significantly lower than on NB. In patients, changes in the SSR were observed 4 minutes into the anti-GD2 mAb naxitamab infusion. SSR latency quickly shortened followed by gradual decrease in the amplitude before disappearance. SSR response did not recover for 24 hours consistent with tachyphylaxis and absence of side effects in the clinic. The Step-Up protocol dissociated on-target off-tumor side effects while maintaining serum drug exposure.

Conclusion

We provide first evidence of the ANS as the principal non-tumor target of anti-GD2 mAbs in humans. We describe the development and modeling of the Step-Up protocol exploiting the tachyphylaxis phenomenon we demonstrate in patients using the SSR test.

A novel approach to guide GD2-targeted therapy in pediatric tumors by PET and [64Cu]Cu-NOTA-ch14.18/CHO

Background: The tumor-associated disialoganglioside GD2 is a bona fide immunotherapy target in neuroblastoma and other childhood tumors, including Ewing sarcoma and osteosarcoma. GD2-targeting antibodies proved to be effective in neuroblastoma and GD2-targeting chimeric antigen receptors (CAR)- expressing T cells as well as natural killer T cells (NKTs) are emerging. However, assessment of intra- and intertumoral heterogeneity has been complicated by ineffective immunohistochemistry as well as sampling bias in disseminated disease. Therefore, a non-invasive approach for the assessment and visualization of GD2 expression in-vivo is of upmost interest and might enable a more appropriate treatment stratification. Methods: Recently, [64Cu]Cu-NOTA-ch14.18/CHO (64Cu-GD2), a radiolabeled GD2-antibody for imaging with Positron-Emission-Tomography (PET) was developed. We here report our first clinical patients' series (n = 11) in different pediatric tumors assessed with 64Cu-GD2 PET/MRI. GD2-expression in tumors and tissue uptake in organs was evaluated by semiquantitative measurements of standardized uptake values (SUV) with PET/MRI on day 1 p.i. (n = 11) as well as on day 2 p.i. (n = 6). Results: In 8 of 9 patients with suspicious tumor lesions on PET/MRI at least one metastasis showed an increased 64Cu-GD2 uptake and a high tracer uptake (SUVmax > 10) was measured in 4 of those 8 patients. Of note, sufficient image quality with high tumor to background contrast was readily achieved on day 1. In case of 64Cu-GD2-positive lesions, an excellent tumor to background ratio (at least 6:1) was observed in bones, muscles or lungs, while lower tumor to background contrast was seen in the spleen, liver and kidneys. Furthermore, we demonstrated extensive tumor heterogeneity between patients as well as among different metastatic sites in individual patients. Dosimetry assessment revealed a whole-body dose of only 0.03 mGy/MBq (range 0.02-0.04). Conclusion: 64Cu-GD2 PET/MRI enables the non-invasive assessment of individual heterogeneity of GD2 expression, which challenges our current clinical practice of patient selection, stratification and immunotherapy application scheme for treatment with anti-GD2 directed therapies.

Targeted therapies in retinoblastoma: GD2-directed immunotherapy following autologous stem cell transplantation and evaluation of alternative target B7-H3

BACKGROUND

GD2-directed immunotherapy is highly effective in the treatment of high-risk neuroblastoma (NB), and might be an interesting target also in other high-risk tumors.

METHODS

The German-Austrian Retinoblastoma Registry, Essen, was searched for patients, who were treated with anti-GD2 monoclonal antibody (mAb) dinutuximab beta (Db) in order to evaluate toxicity, response and outcome in these patients. Additionally, we evaluated anti-GD2 antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in retinoblastoma cell lines in vitro. Furthermore, in vitro cytotoxicity assays directed against B7-H3 (CD276), a new identified potential target in RB, were performed.

RESULTS

We identified four patients with relapsed stage IV retinoblastoma, who were treated with Db following autologous stem cell transplantation (ASCT). Two out of two evaluable patients with detectable tumors responded to immunotherapy. One of these and another patient who received immunotherapy without residual disease relapsed 10 and 12 months after start of Db. The other patients remained in remission until last follow-up 26 and 45 months, respectively. In vitro, significant lysis of RB cell lines by ADCC and CDC with samples from patients and healthy donors and anti-GD2 and anti-CD276-mAbs were demonstrated.

CONCLUSION

Anti-GD2-directed immunotherapy represents an additional therapeutic option in high-risk metastasized RB. Moreover, CD276 is another target of interest.

Cost-effectiveness analysis of dinutuximab β for the treatment of high-risk neuroblastoma in China

BACKGROUND

Dinutuximab β can be used to treat children with high-risk neuroblastoma (NB). Due to its high price, whether dinutuximab β is cost-effective for the treatment of high-risk NB remains uncertain. Therefore, assessing the cost-effectiveness of dinutuximab β in children with high-risk NB is of high importance.

METHODS

The health utilities and economic outcomes in children with high-risk NB were projected using a partitioned survival model. The individual patient data (IPD) of add-on treatment with dinutuximab β (GD2 group) were derived from the literature, while the IPD of traditional therapy (TT group) were obtained from retrospective data of Shanghai Children's Medical Center. Treatment costs included drugs, adverse event-related expenses, and medical resource use. Utility values were obtained from the literature. Costs and quality-adjusted life-years (QALYs) were measured over a 10-year time horizon. Deterministic sensitivity analyses (DSA) and probabilistic sensitivity analyses (PSA) were also conducted.

RESULTS

Compared with the TT group, QALY increased in the GD2 group by 0.72 with an increased cost of $171,269.70, leading to an incremental cost-effectiveness ratio of 236,462.75$/QALY. DSA showed that the price of dinutuximab β was the main factor on the results than other parameters. Compared with the TT group, the GD2 group could not be cost-effective in the PSA at the $37,920/QALY threshold.

CONCLUSION

Results found that dinutuximab β is not a cost-effective treatment option for children with high-risk NB unless its price is significantly reduced.

Long-term, continuous infusion of single-agent dinutuximab beta for relapsed/refractory neuroblastoma: an open-label, single-arm, Phase 2 study

BACKGROUND

Short-term infusions of dinutuximab beta plus isotretinoin and cytokines administered in previous immunotherapy studies in neuroblastoma were associated with severe pain. Here, long-term, continuous infusion of single-agent dinutuximab beta was evaluated in patients with relapsed/refractory neuroblastoma.

METHODS

In this open-label, single-arm, Phase 2 study, patients with either refractory or relapsed high-risk neuroblastoma received dinutuximab beta by continuous infusion over 10 days of each cycle, for up to five cycles. The primary endpoint was objective response rate 24 weeks after the end of cycle 5. Secondary endpoints included adverse events, intravenous morphine use, best response, duration of response, and three-year progression-free and overall survival.

RESULTS

Of the 40 patients included, 38 had evaluable response. Objective response rate was 26% and best response rate 37%. Median duration of response was 238 days (IQR 108-290). Three-year progression-free and overall survival rates were 31% (95% CI 17-47) and 66% (95% CI 47-79), respectively. Prophylactic intravenous morphine use and duration of use decreased with increasing cycles. The most common grade 3 treatment-related adverse events were pain, diarrhea, and hypokalemia.

CONCLUSION

Long-term continuous infusion of single-agent dinutuximab beta is tolerable and associated with clinically meaningful responses in patients with relapsed/refractory high-risk neuroblastoma.

CLINICAL TRIAL REGISTRATION

The study is registered with ClinicalTrials.gov (NCT02743429) and EudraCT (2014-000588-42).

Multimodal Therapy with Consolidating Haploidentical Stem Cell Transplantation and Dinutuximab Beta for Patients with High-Risk Neuroblastoma and Central Nervous System Relapse

Despite highly intensive multimodality treatment regimens, the prognosis of patients with high-risk neuroblastoma (HRNB) and central nervous system (CNS) relapse remains poor. We retrospectively reviewed data from 13 patients with HRNB and CNS relapse who received multimodal therapy with consolidating haploidentical stem cell transplantation (haplo-SCT) followed by dinutuximab beta ± subcutaneous interleukin-2 (scIL-2). Following individual relapse treatment, patients aged 1-21 years underwent haplo-SCT with T/B-cell-depleted grafts followed by dinutuximab beta 20 mg/m2/day × 5 days for 5-6 cycles. If a response was demonstrated after cycle 5 or 6, patients received up to nine treatment cycles. After haplo-SCT, eight patients had a complete response, four had a partial response, and one had a stable disease. All 13 patients received ≥3 cycles of immunotherapy. At the end of the follow-up, 9/13 patients (66.7%) demonstrated complete response. As of July 2023, all nine patients remain disease-free, with a median follow-up time of 5.1 years since relapse. Estimated 5-year event-free and overall survival rates were 55.5% and 65.27%, respectively. Dinutuximab beta ± scIL-2 following haplo-SCT is a promising treatment option with a generally well-tolerated safety profile for patients with HRNB and CNS relapse.

Development and validation of a nomogram based on common biochemical indicators for survival prediction of children with high-risk neuroblastoma: A valuable tool for resource-limited hospitals

BACKGROUND

Despite multiple attempts have been made to develop risk stratification within high-risk neuroblastoma (NB) patients (age of diagnosis ≥ 18 month-old with metastatic NB), the definition of "ultra high-risk NB" is still lack of consensus, and indicators for identifying this subgroup are still unclear. This study aimed to develop a nomogram based on easy-to-obtain blood-derived biofactors for identifying ultra high-risk NB patients with highest risk of death within 3 or 5 years.

METHODS

One hundred sixty-seven NB patients who treated at Sun Yat-sen University Cancer Center between 2015 and 2023 were recruited and clustered randomly into training and validation cohorts (116 and 51 cases, respectively). Univariate and multivariate Cox analysis were performed in training set to screen independent prognostic indicators for constructing nomogram model of predicting 1-, 3- and 5-year overall survival (OS). The discrimination power of the nomogram in training and validation sets were assessed by concordance index (C-index) and calibration plot. Based on the risk score obtained from nomogram model, the prognostic accuracy of 1-, 3- and 5-year OS rates in training and validation cohorts were further evaluated using the area under receiver operating characteristic (ROC) curves (AUC).

RESULTS

Through univariate and multivariate Cox analysis, independent prognostic indicators, including serum lactate dehydrogenase (LDH) and albumin (ALB), were identified in training set, and used to establish a nomogram model. The model showed good discrimination power with C-index in training cohort being 0.706 (95%CI: 0.633-0.788). According to the cut-point calculated based on the established nomogram, patients with a nomogram score > 34 points could be stratified to ultra high-risk NB subgroup, and this subgroup had poorer OS than those in non-ultra one (p < 0.001). AUC values of ROC curves for 3- and 5-year OS rates in the training set were 0.758 and 0.756, respectively. Moreover, based on the cut-point score (34 points) developed in training set, The model also showed good discrimination power with C-index of 0.773 (95%CI: 0.664-0.897) and powerful prognostic accuracy of AUC for 3- and 5-year OS rates being 0.825 and 0.826, respectively, in validation cohort.

CONCLUSIONS

We developed a simple-to-use nomogram based on common laboratory indicators to identify the subgroup of ultra high-risk NB before treatment, providing these children even from developing countries or regions access to intensified multimodal treatments earlier and thus improving their long-term outcome.

Dinutuximab Beta Maintenance Therapy in Patients with High-Risk Neuroblastoma in First-Line and Refractory/Relapsed Settings-Real-World Data

Dinutuximab beta is approved for the maintenance treatment of patients with high-risk neuroblastoma (HR-NB), including patients with relapsed/refractory (R/R) disease. However, the data on its use in real-world clinical practice is limited. We retrospectively reviewed the clinical records of 54 patients with HR-NB who received maintenance therapy with dinutuximab beta in first-line (37 patients) or R/R settings (17 patients) at three centers in Poland. Of the 37 patients who received first-line treatment, twenty-eight had a complete response, two had a partial response, three had progressive disease, and four relapsed at the end of treatment. The median overall survival (OS) was 24.37 months, and the three-year progression-free survival (PFS) and OS were 0.63 and 0.80, respectively. Of the 17 patients in the R/R group, 11 had a complete response, two had a partial response, one had stable disease, and three had progressive disease or relapsed at the end of treatment. The median OS was 33.1 months and the three-year PFS and OS were 0.75 and 0.86, respectively. Treatment was generally well tolerated, including in patients with co-morbidities and those who had experienced toxicities with previous therapies. These findings demonstrate that the use of dinutuximab beta is feasible and beneficial as a first-line or R/R treatment in routine clinical practice in Poland.

Effect and Tolerance of N5 and N6 Chemotherapy Cycles in Combination with Dinutuximab Beta in Relapsed High-Risk Neuroblastoma Patients Who Failed at Least One Second-Line Therapy

The anti-disialoganglioside (GD2) monoclonal antibody dinutuximab beta is approved for the maintenance treatment of high-risk neuroblastoma. Dinutuximab beta combined with different chemotherapy regimens is being investigated in various clinical settings. We conducted a retrospective clinical chart review of 25 patients with relapsed/refractory neuroblastoma who had failed ≥1 second-line therapy and received compassionate use treatment with dinutuximab beta long-term infusion combined with the induction chemotherapy regimens N5 (cisplatin, etoposide, vindesine) and N6 (vincristine, dacarbazine, ifosfamide, doxorubicin) recommended by the German Pediatric Oncology and Hematology Group [GPOH] guidelines. The treatment did not result in any unexpected severe toxicities or in any major treatment delays. Grade 3/4 pain was reported by 4/25 patients in cycle 1, decreasing to 0/9 patients in cycles 3 and 4. The median follow-up was 0.6 years. The best response in this group was 48% (12/25 patients), which included three patients with minor responses. At 1 year, the estimated event-free survival was 27% (95% confidence interval [CI] 8-47) and overall survival was 44% (95% CI 24-65). Combining long-term infusion of dinutuximab beta with N5 and N6 chemotherapy demonstrated an acceptable safety profile and encouraging objective response rates in heavily pretreated patients with high-risk neuroblastoma, warranting further evaluation in clinical trials.

Pain mitigation and management strategies for anti-GD2 infusions: An expert consensus

Monoclonal antibodies (mAbs) targeting disialoganglioside 2 (GD2) are an important treatment advance for high-risk neuroblastoma, including in patients with refractory or relapsed disease. Dinutuximab and dinutuximab beta are administered for ≥8 hours (and up to 10 days for dinutuximab beta), whereas naxitamab is administered over 0.5 to 2 hours as tolerated. As acute pain is a class effect of anti-GD2 mAbs, effective pain management is crucial to successful treatment. Here, we provide an overview of current pain-management strategies for anti-GD2 mAb infusions, with a focus on strategies suitable for naxitamab infusions, which cause a more rapid onset of often severe pain. We discuss opioid analgesics, ketamine, gabapentin, and other similar agents and nonpharmacologic approaches. Potential future pain-management options are also discussed, in addition to the use of sedatives to reduce the anxiety that may be associated with infusion-related pain. In this expert consensus paper, specific guidance for pain management during naxitamab infusions is provided, as these infusions are administered over 0.5 to 2 hours and may not need overnight hospitalization based on the physician's assessment, and require rapid-onset analgesia options suitable for potential outpatient administration.

Dinutuximab beta combined with chemotherapy in patients with relapsed or refractory neuroblastoma

Prognosis in children with refractory and relapsed high-risk neuroblastoma is poor. Only a minority of patients obtain remission when treated with second-line chemotherapy regimens. Chemotherapy combined with anti-GD2 antibodies has previously been shown to increase response and survival rates. We retrospectively analyzed a cohort of 25 patients with relapsed or refractory high-risk neuroblastoma who were treated with irinotecan/temozolomide chemotherapy in combination with the anti-GD2 antibody dinutuximab beta. The therapy resulted in an objective response rate of 64%, with 32% of patients achieving a complete response. Response to treatment was observed in patients with refractory disease (n=5) and those with first (n=12) or consecutive (n=8) relapses, including patients with progressing disease. In four patients, best response was achieved after more than 5 cycles, suggesting that some patients may benefit from prolonged chemotherapy and dinutuximab beta treatment. Fourteen of our 25 patients had previously received dinutuximab beta, four of whom achieved complete response and six partial response (objective response rate 71%). The therapy was well tolerated, even in heavily pre-treated patients and those who had previously received dinutuximab beta treatment. Toxicities were comparable to those previously reported for the individual therapies, and no discontinuations due to toxicities occurred. Combination of chemotherapy with dinutuximab beta is a promising treatment option for patients with relapsed or refractory high-risk neuroblastoma and should be further explored in clinical studies.

Novel infusion strategy reduces severe adverse events caused by the anti-GD2 monoclonal antibody naxitamab

Introduction

Anti-disialoganglioside 2 (anti-GD2) monoclonal antibodies (mAbs) are associated with Grade ≥3 (≥G3) adverse events (AEs) such as severe pain, hypotension, and bronchospasm. We developed a novel method of administering the GD2-binding mAb naxitamab, termed "Step-Up" infusion (STU), to reduce the risk of AEs of severe pain, hypotension, and bronchospasm.

Methods

Forty-two patients with GD2-positive tumors received naxitamab under "compassionate use" protocols and administered via either the standard infusion regimen (SIR) or the STU regimen. The SIR comprises a 60-min infusion of 3 mg/kg/day on Day 1 of cycle 1 and a 30- to 60-min infusion on Day 3 and Day 5, as tolerated. The STU regimen uses a 2-h infusion on Day 1, initiated at a rate of 0.06 mg/kg/h during 15 min (0.015 mg/kg) and which increases gradually to a cumulative dose of 3 mg/kg; on Days 3 and 5, the 3-mg/kg dose is initiated at 0.24 mg/kg/h (0.06 mg/kg) and delivered in 90 min according to the same gradual-increase strategy. AEs were graded according to Common Terminology Criteria for Adverse Events version 4.0.

Results

The frequency of infusions with an associated G3 AE was reduced from 8.1% (23/284 infusions) with SIR to 2.5% (5/202 infusions) with STU. The odds of an infusion being associated with a G3 AE reduced by 70.3% with STU vs. SIR (odds ratio: 0.297; p = 0.037). Mean serum naxitamab levels pre- and post-STU (11.46 µg/ml pre-infusion; 100.95 µg/ml post-infusion) were within the range reported for SIR.

Discussion

The comparable pharmacokinetics of naxitamab during SIR and STU may indicate that switching to STU reduces G3 AEs without impact on efficacy.

Recent Evidence-Based Clinical Guide for the Use of Dinutuximab Beta in Pediatric Patients with Neuroblastoma

The anti-GD2 antibody dinutuximab beta (Qarziba^®) has been added to the present standard of care for patients with high-risk neuroblastoma in Europe based on the positive results obtained in different studies. In both the first-line and relapsed/refractory settings, treatment with dinutuximab beta attains objective clinical responses in children with high-risk neuroblastoma. Its incorporation has changed the outcome for these patients and optimized management should be guaranteed to minimize possible adverse effects. Most prevalent adverse events include pain, allergic reactions, fever and capillary leak syndrome. There are still no evidence-based clinical guidelines that include the latest published evidence to optimize its use, as it depends on the experience gained in each referral center. Topics such as the mode of preparation and administration, the concomitant use of interleukin-2, the recommended pediatric age and dose for its use, or the adequate management of possible toxicities are important aspects to review. The objective of this article was to update the clinical guide to management with dinutuximab beta of children with neuroblastoma based on the most recent published evidence and our own experience in clinical practice.

A Retrospective Analysis of the Therapeutic Outcomes of 117 Neuroblastoma Patients Treated at a Single Pediatric Oncology Center in China

OBJECTIVE

Recent therapeutic advances have greatly enhanced the survival rates of patients with neuroblastoma (NB). However, the outcomes of neuroblastoma patients in China, particularly those with high-risk (HR) NB, remain limited.

METHOD

We retrospectively analyzed the clinical data and outcomes of NB patients who were treated at a tertiary pediatric cancer facility in China between January 2013 and October 2021.

RESULTS

A total of 117 NB patients were recruited. Patients with very low-risk (VLR), low-risk (LR), intermediate-risk (IR), and HR-NB patients made up 4%, 27%, 15%, and 54% of total patient population, respectively. Patients diagnosed between 2013 and 2018 were treated according to the protocol of Sun Yat-Sen University Cancer Center and those diagnosed between 2019 and 2021 were treated according to the COG ANBL0531 or ANBL0532 protocol with or without autologous stem cell transplantation (ASCT). The 5-year EFS and OS of all risk groups of patients were 67.29% and 77.90%, respectively. EFS and OS were significantly decreased in patients with higher risk classifications (EFS: VLR/LR vs IR vs HR: 97.22% vs 67.28% vs 51.83%; ***P = .001; OS: VLR/LR vs IR vs HR: 97.06% vs 94.12% vs 64.38%; *P = .046). In HR-NB patients treated according to the COG protocol between 2019 and 2021, the 3-year OS of patients who received tandem ASCT was significantly greater than those who did not receive ASCT (93.33% % vs 47.41%; *P = .046; log-rank test). EFS was not significantly different between patients with and without ASCT (72.16% vs 60.32%).

CONCLUSION

Our findings show that patients with lower risk classification have a positive prognosis for survival. The prognosis of patients with HR-NB remains in need of improvement. ASCT may enhance OS in HR-NB patients; however, protocol adjustment may be necessary to increase EFS in these patients.

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.

Immunotherapy with anti-GD2 monoclonal antibody in infants with high-risk neuroblastoma

Anti-G_D2 monoclonal antibodies (mAb) improve the prognosis of high-risk neuroblastoma (HR-NB). Worldwide experience almost exclusively involves toddlers and older patients treated after multi-modality or 2^nd -line therapies, i.e., many months post-diagnosis. In contrast, at our center, infants received anti-G_D2 mAbs because this immunotherapy started during or immediately after induction chemotherapy. We now report on the feasibility, safety, and long-term survival in this vulnerable age group.Thirty-three HR-NB patients were <19 months old when started on 3F8 (murine mAb; n=21) or naxitamab (humanized-3F8; n=12), with 30-90" intravenous infusions. Patients received analgesics and antihistamines. Common toxicities (pain, urticaria, cough) were manageable, allowing outpatient treatment. Capillary leak, posterior reversible encephalopathy syndrome, and mAb-related long-term toxicities did not occur. Two 3F8 cycles were aborted due to bradycardia (a pre-existing condition) and asthmatic symptoms, respectively. One patient received ½ dose of day 1 naxitamab because of hypotension; full doses were subsequently administered. Post-mAb treatments included chemotherapy, radiotherapy, and anti-NB vaccine. Among 3F8 patients, 17/21 are in complete remission off all treatment at 5.6+-to-24.1+ (median 13.4+) years from diagnosis. Among naxitamab patients, 10/12 remain relapse-free post-mAb at 1.7+-to-4.3+ (median 3.1+) years from diagnosis. Toxicity was similar with short outpatient infusions and matched that observed with these and other anti-G_D2 mAbs in older patients. These findings were reassuring given that naxitamab is dosed >2.5x higher (~270mg/m² /cycle) than 3F8, dinutuximab, and dinutuximab beta (70-100mg/m² /cycle). HR-NB in infants proved to be highly curable. This article is protected by copyright. All rights reserved.

Dinutuximab Beta in Children with High-Risk Neuroblastoma: Experience from a Single Center in Croatia

To determine the potential benefits and feasibility of administering maintenance therapy with dinutuximab beta for high-risk neuroblastoma (HRNB) in clinical practice, a retrospective review of charts of patients with HRNB treated at a single center in Croatia (2012–2021) was undertaken. Of 23 patients with HRNB, 11 received up to five cycles of dinutuximab beta as part of multimodal therapy; 12 patients did not (i.e., no immunotherapy). In the no immunotherapy group, one patient had complete remission (8%), and 11 patients died of tumor progression (92%). In the dinutuximab beta group, eight patients had complete remission (73%; median duration of response 5 years and 2 months), one had stable disease (9%), and two died of disease (18%). Patients who received dinutuximab beta had a higher median event-free survival (40.0 months [range: 12.5–83.0]) and median overall survival (56.0 months [range: 16.2–101.0]) than those who did not (12.9 months [range: 3.3–126.0] and 20.7 months [3.3–126.0], respectively). Dinutuximab beta was generally well tolerated; adverse events were manageable and as reported in clinical studies. These results confirm the benefits and feasibility of maintenance therapy with dinutuximab beta as part of multimodal therapy for patients with HRNB in real-world clinical practice.

Clinical Phenotype and Management of Severe Neurotoxicity Observed in Patients with Neuroblastoma Treated with Dinutuximab Beta in Clinical Trials

Neurotoxicity is an off-tumour, on-target side effect of GD2-directed immunotherapy with monoclonal antibodies. Here, we report the frequency, management and outcome of patients enrolled in two prospective clinical trials who experienced severe neurotoxicity during immunotherapy with the anti-GD2 antibody dinutuximab beta (DB) administered as short-term infusion (HR-NBL1/SIOPEN study, randomisation R2, EudraCT 2006-001489-17) or as long-term infusion (HR-NBL1/SIOPEN study, randomisation R4, EudraCT 2006-001489-17 and LTI/SIOPEN study, EudraCT 2009-018077-31), either alone or with subcutaneous interleukin-2 (scIL-2). The total number of patients included in this analysis was 1102. Overall, 44/1102 patients (4.0%) experienced Grade 3/4 neurotoxicities (HR-NBL1 R2, 21/406; HR-NBL1 R4, 8/408; LTI study, 15/288), including 27 patients with severe neurotoxicities (2.5%). Events occurred predominantly in patients receiving combined treatment with DB and scIL-2. Neurotoxicity was treated using dexamethasone, prednisolone, intravenous immunoglobulins and, in two patients, plasmapheresis, which was highly effective. While neurological recovery was observed in 16 of 21 patients with severe neurotoxicities, 5/1102 (0.45%) patients experienced persistent and severe neurological deficits. In conclusion, severe neurotoxicity is most commonly observed in patients receiving DB with scIL-2. Considering the lack of clinical benefit for IL-2 in clinical trials so far, the administration of IL-2 alongside DB is not recommended.