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).

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.

Combined Blockade of TIGIT and PD-L1 Enhances Anti-Neuroblastoma Efficacy of GD2-Directed Immunotherapy with Dinutuximab Beta

Immunotherapies against high-risk neuroblastoma (NB), using the anti-GD2 antibody (Ab) dinutuximab beta (DB), significantly improved patient survival. Ab-dependent cellular cytotoxicity (ADCC) is one of the main mechanisms of action and it is primarily mediated by NK cells. To further improve antitumor efficacy, we investigated here a combinatorial immunotherapy with DB and the double immune checkpoint blockade of T-cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) and programmed cell death ligand-1 (PD-L1). The effects of ADCC, mediated by DB against NB cells on NK-cell activity, and the expression of TIGIT and CD226 and their ligands CD112 and CD155, as well as of PD-1 and PD-L1 on NB and effector cells, were investigated using flow cytometry. ADCC was assessed with a calcein-AM-based cytotoxicity assay. The efficacy of a combinatorial immunotherapy with DB, given as a long-term treatment, and the double immune checkpoint blockade of TIGIT and PD-L1 was shown using a resistant murine model of NB, followed by an analysis of the tumor tissue. We detected both TIGIT ligands, CD112 and CD155, on all NB cell lines analyzed. Although ADCC by DB resulted in a strong activation of NK cells leading to an effective tumor cell lysis, a remarkable induction of PD-L1 expression on NB cells, and of TIGIT and PD-1 on effector cells, especially on NK cells, was observed. Additional anti-TIGIT or anti-PD-L1 treatments effectively inhibited tumor growth and improved survival of the mice treated with DB. The superior antitumor effects were observed in the "DB + double immune checkpoint blockade" group, showing an almost complete eradication of the tumors and the highest OS, even under resistant conditions. An analysis of tumor tissue revealed both TIGIT and TIGIT ligand expression on myeloid-derived suppressor cells (MDSCs), suggesting additional mechanisms of protumoral effects in NB. Our data show that the targeting of TIGIT and PD-L1 significantly improves the antitumor efficacy of anti-GD2 immunotherapy, with DB presenting a new effective combinatorial treatment strategy against high-risk tumors.

Chemotherapeutics Used for High-Risk Neuroblastoma Therapy Improve the Efficacy of Anti-GD2 Antibody Dinutuximab Beta in Preclinical Spheroid Models

Anti-disialoganglioside GD2 antibody ch14.18/CHO (dinutuximab beta, DB) improved the outcome of patients with high-risk neuroblastoma (HR-NB) in the maintenance phase. We investigated chemotherapeutic compounds used in newly diagnosed patients in combination with DB. Vincristine, etoposide, carboplatin, cisplatin, and cyclophosphamide, as well as DB, were used at concentrations achieved in pediatric clinical trials. The effects on stress ligand and checkpoint expression by neuroblastoma cells and on activation receptors of NK cells were determined by using flow cytometry. NK-cell activity was measured with a CD107a/IFN-γ assay. Long-term cytotoxicity was analyzed in three spheroid models derived from GD2-positive neuroblastoma cell lines (LAN-1, CHLA 20, and CHLA 136) expressing a fluorescent near-infrared protein. Chemotherapeutics combined with DB in the presence of immune cells improved cytotoxic efficacy up to 17-fold compared to in the controls, and the effect was GD2-specific. The activating stress and inhibitory checkpoint ligands on neuroblastoma cells were upregulated by the chemotherapeutics up to 9- and 5-fold, respectively, and activation receptors on NK cells were not affected. The CD107a/IFN-γ assay revealed no additional activation of NK cells by the chemotherapeutics. The synergistic effect of DB with chemotherapeutics seems primarily attributed to the combined toxicity of antibody-dependent cellular cytotoxicity and chemotherapy, which supports further clinical evaluation in frontline induction therapy.

BCL11B depletion induces the development of highly cytotoxic innate T cells out of IL-15 stimulated peripheral blood αβ CD8+ T cells

BCL11B, an essential transcription factor for thymopoiesis, regulates also vital processes in post-thymic lymphocytes. Increased expression of BCL11B was recently correlated with the maturation of NK cells, whereas reduced BCL11B levels were observed in native and induced T cell subsets displaying NK cell features. We show that BCL11B-depleted CD8+ T cells stimulated with IL-15 acquired remarkable innate characteristics. These induced innate CD8+ (iiT8) cells expressed multiple innate receptors like NKp30, CD161, and CD16 as well as factors regulating migration and tissue homing while maintaining their T cell phenotype. The iiT8 cells effectively killed leukemic cells spontaneously and neuroblastoma spheroids in the presence of a tumor-specific monoclonal antibody mediated by CD16 receptor activation. These iiT8 cells integrate the innate natural killer cell activity with adaptive T cell longevity, promising an interesting therapeutic potential. Our study demonstrates that innate T cells, albeit of limited clinical applicability given their low frequency, can be efficiently generated from peripheral blood and applied for adoptive transfer, CAR therapy, or combined with therapeutic antibodies.

Immune Response and Outcome of High-Risk Neuroblastoma Patients Immunized with Anti-Idiotypic Antibody Ganglidiomab: Results from Compassionate-Use Treatments

(1) Background: High-risk neuroblastoma (HR-NB) is associated with a poor prognosis despite a multimodal high-intensity treatment regimen, including immunotherapy with anti-GD2 monoclonal antibodies (mAb). Here, we investigated the effects of an anti-idiotypic vaccine based on the mAb ganglidiomab that structurally mimics GD2. (2) Methods: Patients with HR-NB treated with anti-GD2 mAb dinutuximab beta and who achieved complete remission after frontline or salvage therapy were offered the vaccine (0.5 mg ganglidiomab adsorbed to Alhydrogel^®). Side effects (CTCAE v4.03) and immune responses were determined on each visit. We also evaluated the time to relapse or progression until the last follow-up. (3) Results: Seven HR-NB patients (five frontlines, two relapsed) received 6-22 subcutaneous injections every two weeks. Six of the seven patients showed an immune response. The non-responding patient had a haploidentical stem cell transplantation as part of the previous treatment. No fever, pain, neuropathy, or toxicities ≥ grade 3 occurred during or post-treatment. All immunized patients did not experience relapses or progressions of their neuroblastoma. (4) Conclusions: This is the first-in-man use of the ganglidiomab vaccine, which was well-tolerated, and all patients not pre-treated by haploidentical transplantation developed vaccine-specific immune responses. These findings provide an important basis for the design of prospective clinical trials.

Immunophenotyping of Circulating and Intratumoral Myeloid and T Cells in Glioblastoma Patients

Glioblastoma is the most common and lethal primary brain malignancy that almost inevitably recurs as therapy-refractory cancer. While the success of immune checkpoint blockade (ICB) revealed the immense potential of immune-targeted therapies in several types of cancers outside the central nervous system, it failed to show objective responses in glioblastoma patients as of now. The ability of glioblastoma cells to drive multiple modes of T cell dysfunction while exhibiting low-quality neoepitopes, low-mutational load, and poor antigen priming limits anti-tumor immunity and efficacy of antigen-unspecific immunotherapies such as ICB. An in-depth understanding of the GBM immune landscape is essential to delineate and reprogram such immunosuppressive circuits during disease progression. In this view, the present study aimed to characterize the peripheral and intratumoral immune compartments of 35 glioblastoma patients compared to age- and sex-matched healthy control probands, particularly focusing on exhaustion signatures on myeloid and T cell subsets. Compared to healthy control participants, different immune signatures were already found in the peripheral circulation, partially related to the steroid medication the patients received. Intratumoral CD4+ and CD8+ TEM cells (CD62L^low/CD45RO^high) revealed a high expression of PD1, which was also increased on intratumoral, pro-tumorigenic macrophages/microglia. Histopathological analysis further identified high PSGL-1 expression levels of the latter, which has recently been linked to increased metastasis in melanoma and colon cancer via P-selectin-mediated platelet activation. Overall, the present study comprises immunophenotyping of a patient cohort to give implications for eligible immunotherapeutic targets in neurooncology in the future.

The Immunocytokine FAP-IL-2v Enhances Anti-Neuroblastoma Efficacy of the Anti-GD2 Antibody Dinutuximab Beta

Simple Summary

Since IL-2 co-treatment did not show any therapeutic benefit in the GD₂-directed treatment of high-risk neuroblastoma (NB) but strongly induced regulatory T cells (Treg), we investigated here the immunocytokine FAP-IL-2v stimulating NK and cytotoxic T cells without induction of Treg. We first detected FAP on NB- and myeloid-derived suppressor cells (MDCS) in tumor tissue and showed a tumor-cell-dependent enhancement in FAP expression by fibroblasts. Treatment of leukocytes with FAP-IL-2v increased ADCC mediated by the anti-GD₂ antibody dinutuximab beta (DB) against NB cells. We next evaluated the antitumor efficacy of a combinatorial immunotherapy by applying DB and FAP-IL-2v and observed strongly reduced tumor growth and improved survival in experimental mice. Analysis of tumor tissue revealed increased NK and cytotoxic T cell numbers and reduced Treg compared to controls. Our data show that FAP-IL-2v is a potent immunocytokine that augments the efficacy of DB against NB, providing a promising alternative to IL-2.

Abstract

Treatment of high-risk neuroblastoma (NB) patients with the anti-GD₂ antibody (Ab) dinutuximab beta (DB) improves survival by 15%. Ab-dependent cellular cytotoxicity (ADCC) is the major mechanism of action and is primarily mediated by NK cells. Since IL-2 co-treatment did not show a therapeutic benefit but strongly induced Treg, we investigated here a DB-based immunotherapy combined with the immunocytokine FAP-IL-2v, which comprises a fibroblast activation protein α (FAP)-specific Ab linked to a mutated IL-2 variant (IL-2v) with abolished binding to the high-affinity IL-2 receptor, thus stimulating NK cells without induction of Treg. Effects of FAP-IL-2v on NK cells, Treg and ADCC mediated by DB, as well as FAP expression in NB, were investigated by flow cytometry, calcein-AM-based cytotoxicity assay and RT-PCR analysis. Moreover, the impact of soluble factors released from tumor cells on FAP expression by primary fibroblasts was assessed. Finally, a combined immunotherapy with DB and FAP-IL-2v was evaluated using a resistant syngeneic murine NB model. Incubation of leukocytes with FAP-IL-2v enhanced DB-specific ADCC without induction of Treg. FAP expression on NB cells and myeloid-derived suppressor cells (MDCS) in tumor tissue was identified. A tumor-cell-dependent enhancement in FAP expression by primary fibroblasts was demonstrated. Combination with DB and FAP-IL-2v resulted in reduced tumor growth and improved survival. Analysis of tumor tissue revealed increased NK and cytotoxic T cell numbers and reduced Treg compared to controls. Our data show that FAP-IL-2v is a potent immunocytokine that augments the efficacy of DB against NB, providing a promising alternative to IL-2.

First-line Anti-GD2 Therapy Combined With Consolidation Chemotherapy in 3 Patients With Newly Diagnosed Metastatic Ewing Sarcoma or Ewing-like Sarcoma

Despite multimodal therapy, the prognosis of patients with metastatic Ewing sarcoma (ES) remains poor, with new treatments urgently needed. The disialoganglioside GD2, a well-established tumor-associated antigen, is expressed in 40% to 90% of ES cells, making it a suitable therapeutic target. Here we report 3 cases with newly diagnosed, metastatic, GD2-positive ES or Ewing-like sarcoma treated with the anti-GD2 antibody dinutuximab beta in addition to standard chemotherapeutic regimens. Treatment was well-tolerated, and all patients achieved complete remission, without evidence of relapse. First-line anti-GD2 immunotherapy in patients with metastatic, GD2-positive ES or Ewing-like sarcoma represents a promising therapeutic option that warrants further clinical evaluation.

GMP-Compliant Manufacturing of TRUCKs: CAR T Cells targeting GD2 and Releasing Inducible IL-18

Chimeric antigen receptor (CAR)-engineered T cells can be highly effective in the treatment of hematological malignancies, but mostly fail in the treatment of solid tumors. Thus, approaches using 4^th advanced CAR T cells secreting immunomodulatory cytokines upon CAR signaling, known as TRUCKs (“T cells redirected for universal cytokine-mediated killing”), are currently under investigation. Based on our previous development and validation of automated and closed processing for GMP-compliant manufacturing of CAR T cells, we here present the proof of feasibility for translation of this method to TRUCKs. We generated IL-18-secreting TRUCKs targeting the tumor antigen GD₂ using the CliniMACS Prodigy^® system using a recently described “all-in-one” lentiviral vector combining constitutive anti-GD₂ CAR expression and inducible IL-18. Starting with 0.84 x 10⁸ and 0.91 x 10⁸ T cells after enrichment of CD4⁺ and CD8⁺ we reached 68.3-fold and 71.4-fold T cell expansion rates, respectively, in two independent runs. Transduction efficiencies of 77.7% and 55.1% was obtained, and yields of 4.5 x 10⁹ and 3.6 x 10⁹ engineered T cells from the two donors, respectively, within 12 days. Preclinical characterization demonstrated antigen-specific GD₂-CAR mediated activation after co-cultivation with GD₂-expressing target cells. The functional capacities of the clinical-scale manufactured TRUCKs were similar to TRUCKs generated in laboratory-scale and were not impeded by cryopreservation. IL-18 TRUCKs were activated in an antigen-specific manner by co-cultivation with GD₂-expressing target cells indicated by an increased expression of activation markers (e.g. CD25, CD69) on both CD4⁺ and CD8⁺ T cells and an enhanced release of pro-inflammatory cytokines and cytolytic mediators (e.g. IL-2, granzyme B, IFN-γ, perforin, TNF-α). Manufactured TRUCKs showed a specific cytotoxicity towards GD₂-expressing target cells indicated by lactate dehydrogenase (LDH) release, a decrease of target cell numbers, microscopic detection of cytotoxic clusters and detachment of target cells in real-time impedance measurements (xCELLigence). Following antigen-specific CAR activation of TRUCKs, CAR-triggered release IL-18 was induced, and the cytokine was biologically active, as demonstrated in migration assays revealing specific attraction of monocytes and NK cells by supernatants of TRUCKs co-cultured with GD₂-expressing target cells. In conclusion, GMP-compliant manufacturing of TRUCKs is feasible and delivers high quality T cell products.

Comparison of three different methods to detect bone marrow involvement in patients with neuroblastoma

Purpose

Neuroblastoma (NB) is the most frequent extracranial tumor in children. The detection of bone marrow (BM) involvement is crucial for correct staging and risk-adapted treatment. We compared three methods regarding the detection of NB involvement in BM.

Methods

Eighty-one patients with NB were included in this retrospective study. BM samples were obtained at designated time points at study entry and during treatment or follow-up. The diagnostic tools for BM analysis included cytomorphology (CM), flow cytometry (FCM) and automatic immunofluorescence plus fluorescence in situ hybridization (AIPF).

Results

We analyzed 369 aspirates in 81 patients in whom AIPF, CM, and FCM were simultaneously available. During the observation period, NB cells were detected in 86/369 (23.3%) cases, by CM in 32/369 (8.7%), by FCM in 52 (14.1%), and by AIPF in 72 (19.5%) samples. AIPF and/or FCM confirmed all positive results obtained in CM and detected 11 additional positive BM aspirates in 294 CM negative samples (p < 0,001). Survival of patients with BM involvement at study entry identified solely by FCM/AIPF was 17.4% versus 0% for patients in whom BM involvement was already identified by CM.

Conclusion

The combination of AIPF/FCM yielded the highest detection rate of NB cells in BM. AIPF was the single, most sensitive method in detecting these cells. Although CM did not provide any additional positive results, it is still a useful, readily available and cost-effective tool. The prognostic significance of FCM and AIPF should be confirmed in a prospective study with a larger number of patients.

Immunomonitoring of Stage IV Relapsed Neuroblastoma Patients Undergoing Haploidentical Hematopoietic Stem Cell Transplantation and Subsequent GD2 (ch14.18/CHO) Antibody Treatment

Haploidentical stem cell transplantation (haplo SCT) in Stage IV neuroblastoma relapsed patients has been proven efficacious, while immunotherapy utilizing the anti-GD2 antibody dinutuximab beta has become a standard treatment for neuroblastoma. The combinatorial therapy of haplo SCT and dinutuximab may potentiate the efficacy of the immunotherapy. To gain further understanding of the synergistic effects, functional immunomonitoring was assessed during the clinical trial CH14.18 1021 Antibody and IL2 After haplo SCT in Children with Relapsed Neuroblastoma (NCT02258815). Rapid immune reconstitution of the lymphoid compartment was confirmed, with clinically relevant dinutuximab serum levels found in all patients over the course of treatment. Only one patient developed human anti-chimeric antibodies (HACAs). In-patient monitoring revealed highly functional NK cell posttransplant capable of antibody-dependent cellular cytotoxicity (ADCC). Degranulation of NK cell subsets revealed a significant response increased by dinutuximab. This was irrespective of the KIR receptor–ligand constellation within the NK subsets, defined by the major KIR receptors CD158a, CD158b, and CD158e. Moreover, complement-dependent cytotoxicity (CDC) was shown to be an extremely potent effector-cell independent mechanism of tumor cell lysis, with a clear positive correlation to GD2 expression on the cancer cells as well as to the dinutuximab concentrations. The ex vivo testing of patient-derived effector cells and the sera collected during dinutuximab therapy demonstrated both high functionality of the newly established lymphoid immune compartment and provided confidence that the antibody dosing regimen was sufficient over the duration of the dinutuximab therapy (up to nine cycles in a 9-month period). During the course of the dinutuximab therapy, proinflammatory cytokines and markers (sIL2R, TNFa, IL6, and C reactive protein) were significantly elevated indicating a strong anti-GD2 immune response. No impact of FcGR polymorphism on event-free and overall survival was found. Collectively, this study has shown that in-patient functional immunomonitoring is feasible and valuable in contributing to the understanding of anti-cancer combinatorial treatments such as haplo SCT and antibody immunotherapy.

Inebilizumab in AQP4-Ab-positive neuromyelitis optica spectrum disorder

Until recently, the use of preventative immunotherapy in neuromyelitis optica spectrum disorders (NMOSD) was based on observational studies and clinical experiences. Meanwhile, the first drugs, among others the monoclonal antibody inebilizumab, were approved for the treatment of aquaporin-4 (AQP4) antibody-positive NMOSD. Inebilizumab binds to the CD19 antigen on B cells and leads to B-cell depletion. The first two dosages of 300 mg inebilizumab are administered intravenously at an interval of 2 weeks followed by further infusions every 6 months. In the placebo-controlled pivotal phase II/III study N-MOmentum, inebilizumab significantly prolonged the time to a first adjudicated relapse in AQP4 antibody-positive patients compared with placebo. The most frequent side effects were infusion reactions, urinary and respiratory tract infections, and arthralgia. This review presents data on clinical and preclinical pharmacology, administration, safety aspects and clinical trials of inebilizumab.

Nivolumab and dinutuximab beta in two patients with refractory neuroblastoma

BACKGROUND

Neuroblastoma (NB) is the most frequent extracranial solid tumor in children. More than 50% of patients present with widespread (stage M) or refractory disease. In these patients, event-free and overall survival was improved by the addition of the anti-disialoganglioside antibody dinutuximab beta (DB) following multimodal conventional therapy. However, the prognosis of patients with refractory/relapsed NB remains poor. In the past decade, immunotherapy approaches with checkpoint inhibitors were approved for patients with certain malignant diseases such as melanoma or Hodgkin lymphoma. In preclinical models, DB resulted in an upregulation of the programmed cell death protein 1 (PD-1) checkpoint in NB cell lines and a combined treatment of DB with a murine anti-PD-1 checkpoint inhibitor showed a synergistic effect in a NB mouse model.

CASE PRESENTATIONS

Two patients were admitted with refractory metastatic NB. In the 4-year-old girl, NB was diagnosed in 2013. She completed her first-line therapy with a first remission in 2015, but suffered a relapse in 2017. Treatment with chemotherapy and DB resulted in progressive disease after transient improvement. In the 17-year-old young man, NB was first diagnosed in April 2010. After two local relapses in 2011 and 2014, a metastatic relapse and a large abdominal tumor bulk were found in 2018. Despite transient improvement with multimodal therapy, progressive metastatic disease was observed in May 2019. Both patients had a satisfactory quality of life. Therefore, treatment with DB and nivolumab was performed-in the girl from October 2018 until August 2019, in the young man since June 2019. Tolerance to treatment was excellent. The girl continues to be in complete remission 6 months after therapy was stopped. In the young man, the soft tissue lesions disappeared completely, the skeletal lesions regressed substantially after 9 months of his still ongoing treatment.

CONCLUSIONS

The combination of DB with the checkpoint inhibitor nivolumab led to complete and a very good partial remission in two patients with relapsed/refractory NB. Prospective trials are warranted to clarify the role of this novel approach in a larger number of patients.

Reduction of CD11b+ myeloid suppressive cells augments anti-neuroblastoma immune response induced by the anti-GD2 antibody ch14.18/CHO

Neuroblastoma (NB) still remains a major challenge in pediatric oncology. We recently showed CD11b⁺-dependent upregulation of the PD-1/PD-L1 checkpoint on NB cells treated with the chimeric anti-GD₂ antibody (Ab) ch14.18/CHO. Here, we report effects of reduction of CD11b⁺ myeloid suppressive cells on ch14.18/CHO immunotherapy against NB. Flow cytometry, immunohistochemistry and RT-PCR were used to assess tumor infiltrating leukocytes and expression of myeloid suppressive cell-associated genes. XTT assay was used to show impact of 5-FU on tumor and effector cells. Antitumor effects of the combined treatment with ch14.18/CHO and reduction of myeloid suppressive cells were evaluated in a syngeneic NB mouse model. Tumor tissue of untreated mice showed a strong infiltration by CD11b⁺ cells (53% of all tumor infiltrating leukocytes). RT-PCR analysis of tumors revealed strong expression of the myeloid suppressive cell-associated genes analyzed with the strongest induction of M-CSFr, CCL2, IL-1β, IL-4, IL-6 r, IL-8, Arg1, and NOS2. Compared to controls, application of anti-CD11b Ab resulted in reduction of both CD11b⁺ cells in tumors and expression of myeloid suppressive cell-associated genes as well as delayed tumor growth and prolonged survival. These effects could be further improved by 5-FU. Importantly, the combinatorial immunotherapy with ch14.18/CHO and 5-FU showed the strongest antitumor effects and superior survival rates. In conclusion, reduction of immune suppressive myeloid cells augments anti-NB efficacy of a ch14.18/CHO-based immunotherapy representing a new effective treatment strategy against GD₂-positive cancers.

Neuroblastoma with intracerebral metastases and the need for neurosurgery: a single-center experience

OBJECTIVE

Intracerebral metastases in neuroblastoma patients are rare, and information about the indication for and the outcome of neurosurgical procedures in this setting is scarce in the literature. The authors' aim in the present study was to report a single-center experience with the neurosurgical treatment of intracerebral metastases in neuroblastoma.

METHODS

This study is a retrospective single-center analysis of all neurosurgical strategies used in the treatment of intracerebral metastases in neuroblastoma patients.

RESULTS

Between 2009 and 2017, 237 pediatric patients (94 girls, 143 boys) with a mean age of 39 months at diagnosis were treated for neuroblastoma. Five (2.1%) of the 237 patients had a neurosurgical procedure for intracerebral metastases. The metastases occurred a mean of 46 months after initial diagnosis. All of these patients had neuroblastoma stage 4. Indications for surgery were recurrent metastases after initial successful oncological treatment or progression of the metastasis under oncological treatment as well as deterioration of neurological function. Intraoperatively, the tumor usually had a distinguishable dissection plane but was infiltrative to adjacent nerves in some spots. Mean overall survival after the neurosurgical procedure was 22 months. Furthermore, in another 3 patients, a neurosurgical procedure was done for an intracranial but extracerebral metastasis.

CONCLUSIONS

Neurosurgical procedures for intracerebral metastases in neuroblastoma patients are rare and were performed in 2.1% of patients in the present study. Intracerebral metastases occurred during disease progression, and the prognosis after surgery was very limited. The main indications for surgery were rapid neurological deterioration or recurrence of the metastasis after initial successful oncological treatment. Intraoperatively, the metastases usually had a distinguishable dissection plane from the normal brain tissue.

Impact of IL-2 on Treatment Tolerance in Patients With High-Risk Neuroblastoma Treated With Dinutuximab Beta-Based Immunotherapy

Patients with high-risk neuroblastoma treated with continuous long-term infusion of anti-GD2 antibody dinutuximab beta (DB) in combination with IL-2 show an acceptable safety profile. Here, we compared treatment tolerance with and without IL-2. Ninety-nine patients with high-risk neuroblastoma received up to five cycles of DB given as long-term infusion (10 mg/m²/d, 100 mg/m²; per cycle) with IL-2 (53 patients; regimen A; 6 × 10⁶ IU/m²/d; 60 × 10⁶ IU/m²/cycle) and without IL-2 (46 patients; regimen B) in a single-center compassionate use program. Clinical parameters (body temperature, vital signs, Lansky performance score), laboratory values [C-reactive protein, IFN-γ, IL-6, and IL-18 (cycle 1)], and requirement of i.v. co-medication (e.g., morphine, metamizole) were systematically assessed. Patients with stable clinical parameters and that did not require co-medication were defined as potential "outpatient candidates." Patients showed higher levels of body temperature and CRP in regimen A compared to B. However, IL-6 serum concentrations were similar in pts of both cohorts in the first cycle. Patients receiving regimen B showed a shorter time to achieve normal vital parameters and required less co-medication compared to patients in regimen A that resulted in a shorter median time period to discharge and to achieve a potential outpatient status (6d regimen A and 3-5d regimen B after start of antibody infusion, respectively). This study shows that omitting IL-2 from immunotherapy with DB allows reduced co-medication and hospitalization time and therefore results in improved quality of life in patients with high-risk neuroblastoma.

Low CD4⁺/CD25⁺/CD127⁻ regulatory T cell- and high INF-γ levels are associated with improved survival of neuroblastoma patients treated with long-term infusion of ch14.18/CHO combined with interleukin-2

Immunotherapy with the anti-GD₂ antibody (Ab) ch14.18/CHO in combination with interleukin 2 (IL-2) has improved survival of high-risk neuroblastoma (NB) patients. Here, we report immunotherapy-related effects on circulating NK cells, regulatory T cells (T_regs), granulocytes as well as on Ab-dependent cell-mediated cytotoxicity (ADCC) and cytokines IFN-γ, IL-6, IL-10, IL-18 and CCL2 and their association with progression-free survival (PFS).

In a closed single-center program, 53 patients received five cycles of 6 × 10⁶ IU/m² subcutaneous IL-2 (d1-5; 8–12) combined with long-term infusion (LTI) of 100 mg/m² ch14.18/CHO (d8-18). Immune cells and cytokines were analyzed by flow cytometry and ADCC by calcein-AM-based cytotoxicity assay.

IL-2 administration increased cytotoxic NK cell-, eosinophil- and T_reg counts in cycle 1 (2.9-, 3.1- and 20.7-fold, respectively) followed by further increase in subsequent cycles, whereas neutrophil levels were elevated only after the ch14.18/CHO infusion (2.4-fold change). Serum concentrations of IFN-γ, IL-6, IL-10, IL-18 and CCL2 in cycle 1 were increased during the combinatorial therapy (peak levels of 3,656 ± 655 pg/ml, 162 ± 38 pg/ml, 20.91 ± 4.74 pg/ml, 1,584 ± 196 pg/ml and 2,159 ± 252 pg/ml, respectively). Surprisingly, we did not observe any correlation between NK-, eosinophil- or neutrophil levels and PFS. In contrast, patients with low T_regs showed significantly improved PFS compared to those who had high levels. T_reg counts negatively correlated with INF-γ serum concentrations and patients with high INF-γ and IL-18 had significantly improved survival compared to those with low levels.

In conclusion, LTI of ch14.18/CHO in combination with IL-2 resulted in T_reg induction that inversely correlated with IFN-γ levels and PFS.

Management of tumor rupture and abdominal compartment syndrome in an infant with bilateral high risk stage 4 neuroblastoma: A case report

RATIONALE

Tumor rupture and bleeding at initial presentation of infants with neuroblastoma (NBL) is a rare, but life threatening condition and challenge in pediatric oncology. Here, we report successful multidisciplinary management of an abdominal compartment syndrome as a result of tumor rupture and bleeding in an infant with bilateral high risk stage 4 NBL.

PATIENT CONCERNS

The patient was admitted to a cooperating hospital with vomiting, failure to thrive and a large mass in the abdomen and was then referred to our center.

DIAGNOSES

Stage 4 NBL with MYC-N amplification and 1p36 deletion was diagnosed in an 11 months old girl. Due to rapid and massive tumor growth she developed abdominal compression with renal failure, severe bleeding, and tumor lysis syndrome (TLS).

INTERVENTIONS

Surgical decompression by enterostomy, local, and systemic bleeding control with platelets and coagulation factors, antiinfective and TLS therapy were effective in stabilizing the patient's condition. This allowed initiation of the multimodal antineoplastic treatment according to protocol NB 2004.

OUTCOMES

Mechanical ventilation was stopped after 11 days, the abdominal wall was closed 3 months after the start of therapy, and treatment according to the protocol be started and successfully completed.

LESSONS

Only the immediate, coordinated multidisciplinary intervention managed to overcome the life-threatening abdominal compartment syndrome and its associated problems, eventually enabling successful curative treatment.

Randomized use of anti-GD2 antibody dinutuximab beta (DB) long-term infusion with and without subcutaneous interleukin-2 (scIL-2) in high-risk neuroblastoma patients with relapsed and refractory disease: Results from the SIOPEN LTI-trial

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Background: We determined the role of scIL-2 combined with long term infusion (LTI) of DB in patients (pts) with high-risk relapsed/refractory neuroblastoma. Methods: 160 pts were enrolled into an open label SIOPEN Phase II clinical trial (EudraCT 2009-018077-31). Pts were randomly assigned to receive up to 5 cycles of 100 mg/m2 DB-LTI (d8-17) and 160 mg/m2 oral isotretinoin (d19-32) (81 pts) with and without 6x106IU/m2 scIL-2 (d1-5; 8-12) (79 pts). Endpoints were toxicity, response rates and 2yrs-event free and -overall survival. Results: Between 07/2014 and 07/2017, 160 pts from 11 countries were randomised. Median follow-up is 2.6 years. Pts were well balanced between arms according to stage, age, MYCN amplification, patients with relapse and remission status. The 2yrs-EFS and -OS for DB (81 pts) vs. DB combined with scIL-2 (79 pts) was 59%±6% vs 65%±6% (p = 0.721) and 79%±5% vs 84%±4% (p = 0.904). In 97 pts with evaluable disease, a response rate of 49% (9% CR, 40% PR) vs 52% (26% CR, 26% PR) after treatment with DB vs DB and scIL-2 was observed. Grade 3&4 fever (16% vs 46%, P = 0.000), allergic reaction (1% vs 14%, P = 0.004), hematological toxicity (46% vs 66%, P = 0.013) and neurotoxicity (0% vs 8%, p = 0.003) were significantly worse in the combination arm, but no difference was seen for capillary leak, gastrointestinal, liver enzyme elevation and pain. Paraplegia possibly related to the treatment was observed in 2 pts in the combination arm, none in the arm without scIL-2, and one resolved to baseline. A subgroup of 34 pts who had a relapse and measurable disease at treatment start, showed a 2yrs-EFS and -OS in DB (17 pts) vs DB combined with scIL-2 (17 pts) of 35%±12% vs 69%±12% (p = 0.116) and 59%±12% vs 81%±10% (p = 0.167). However, this trend was statistically not significant. Pharmacokinetic and HACA response between both arms was not different with overlapping antibody concentration-time curves and a HACA response of 15/81 (19%) (DB) vs 16/79 (20%) (DB and scIL-2). Conclusions: No significant difference in efficacy of DB combined with scIL-2 and increased toxicity in this arm suggests that this schedule of scIL-2 is of no additional benefit. Clinical trial information: 2009-018077-31.

EZH2 Inhibition in Ewing Sarcoma Upregulates GD2 Expression for Targeting with Gene-Modified T Cells

Chimeric antigen receptor (CAR) engineering of T cells allows one to specifically target tumor cells via cell surface antigens. A candidate target in Ewing sarcoma is the ganglioside G_D2, but heterogeneic expression limits its value. Here we report that pharmacological inhibition of Enhancer of Zeste Homolog 2 (EZH2) at doses reducing H3K27 trimethylation, but not cell viability, selectively and reversibly induces G_D2 surface expression in Ewing sarcoma cells. EZH2 in Ewing sarcoma cells directly binds to the promoter regions of genes encoding for two key enzymes of G_D2 biosynthesis, and EZH2 inhibition enhances expression of these genes. G_D2 surface expression in Ewing sarcoma cells is not associated with distinct in vitro proliferation, colony formation, chemosensitivity, or in vivo tumorigenicity. Moreover, disruption of G_D2 synthesis by gene editing does not affect its in vitro behavior. EZH2 inhibitor treatment sensitizes Ewing sarcoma cells to effective cytolysis by G_D2-specific CAR gene-modified T cells. In conclusion, we report a clinically applicable pharmacological approach for enhancing efficacy of adoptively transferred G_D2-redirected T cells against Ewing sarcoma, by enabling recognition of tumor cells with low or negative target expression.

Co-expression of IL-15 enhances anti-neuroblastoma effectivity of a tyrosine hydroxylase-directed DNA vaccination in mice

Long-term survival of high-risk neuroblastoma (NB) patients still remains under 50%. Here, we report the generation, in vitro characterization and anti-tumor effectivity of a new bicistronic xenogenic DNA vaccine encoding tyrosine hydroxylase (TH) that is highly expressed in NB tumors, and the immune stimulating cytokine interleukin 15 (IL-15) that induces cytotoxic but not regulatory T cells. The DNA sequences of TH linked to ubiquitin and of IL-15 were integrated into the bicistronic expression vector pIRES. Successful production and bioactivity of the vaccine-derived IL-15- and TH protein were shown by ELISA, bioactivity assay and western blot analysis. Further, DNA vaccine-driven gene transfer to the antigen presenting cells of Peyer’s patches using attenuated Salmonella typhimurium that served as oral delivery system was shown by immunofluorescence analysis. The anti-tumor effect of the generated vaccine was evaluated in a syngeneic mouse model (A/J mice, n = 12) after immunization with S. typhimurium (3× prior and 3× after tumor implantation). Importantly, TH-/IL-15-based DNA vaccination resulted in an enhanced tumor remission in 45.5% of mice compared to controls (TH (16.7%), IL-15 (0%)) and reduced spontaneous metastasis (30.0%) compared to controls (TH (63.6%), IL-15 (70.0%)). Interestingly, similar levels of tumor infiltrating CD8⁺ T cells were observed among all experimental groups. Finally, co-expression of IL-15 did not result in elevated regulatory T cell levels in tumor environment measured by flow cytometry. In conclusion, co-expression of the stimulatory cytokine IL-15 enhanced the NB-specific anti-tumor effectivity of a TH-directed vaccination in mice and may provide a novel immunological approach for NB patients.

Impact of HACA on Immunomodulation and Treatment Toxicity Following ch14.18/CHO Long-Term Infusion with Interleukin-2: Results from a SIOPEN Phase 2 Trial

GD₂-directed immunotherapies improve survival of high-risk neuroblastoma (NB) patients (pts). Treatment with chimeric anti-GD₂ antibodies (Ab), such as ch14.18, can induce development of human anti-chimeric Ab (HACA). Here, we report HACA effects on ch14.18/CHO pharmacokinetics, pharmacodynamics and pain intensity in pts treated by long-term infusion (LTI) of ch14.18/CHO combined with IL-2. 124 pts received up to 5 cycles of ch14.18/CHO 10 days (d) infusion (10 mg/m²/d; d8–18) combined with s.c. IL-2 (6 × 10⁶ IU/m²/d; d1–5, d8–12). HACA, treatment toxicity, ch14.18/CHO levels, Ab-dependent cellular- (ADCC) and complement-dependent cytotoxicity (CDC) were assessed using respective validated assays. HACA-negative pts showed a steadily decreased pain in cycle 1 (74% pts without morphine by d5 of LTI) with further decrease in subsequent cycles. Ch14.18/CHO peak concentrations of 11.26 ± 0.50 µg/mL found in cycle 1 were further elevated in subsequent cycles and resulted in robust GD₂-specific CDC and ADCC. Development of HACA (21% of pts) resulted in strong reduction of ch14.18/CHO levels, abrogated CDC and ADCC. Surprisingly, no difference in pain toxicity between HACA-positive and -negative pts was found. In conclusion, ch14.18/CHO LTI combined with IL-2 results in strong activation of Ab effector functions. Importantly, HACA response abrogated CDC but did not affect pain intensity indicating CDC-independent pain induction.

Inflammatory response and treatment tolerance of long-term infusion of the anti-GD2 antibody ch14.18/CHO in combination with interleukin-2 in patients with high-risk neuroblastoma

BACKGROUND

The monoclonal anti-GD₂ antibody ch14.18/CHO in combination with IL-2 is active and effective in high-risk neuroblastoma (NB) patients. Here, we investigated the inflammatory response and treatment tolerance of long-term infusion (LTI) of ch14.18/CHO (10 × 10 mg/m² ; 24 hr) in combination with subcutaneous (s.c.) IL-2 in a single center program.

METHODS

Fifty-three NB patients received up to six cycles of 100 mg/m² ch14.18/CHO (d8-18, where d represents day(s)) as LTI combined with 6 × 10⁶ IU/m² s.c. IL-2 (d1-5; 8-12) and 160 mg/m² oral 13-cis retinoic acid (RA) (d19-32). Side effects of ch14.18/CHO and IL-2 treatment require hospitalization of patients on d8. Treatment tolerance was evaluated daily with clinical parameters (body temperature, vital signs, Lansky performance status, requirement of i.v. concomitant medication) to define an outpatient candidate status. sIL-2-R and C-reactive protein values were determined to assess the inflammatory response.

RESULTS

LTI of ch14.18/CHO (d8-18) in combination with s.c.IL-2 (d8-12) showed an acceptable treatment tolerance that allowed all patients to receive part of the treatment as an outpatient (median time point of discharge: d15 for all cycles). The treatment tolerance improved from cycle to cycle and the time to become an outpatient candidate decreased from d15 to d13 in subsequent cycles. Clinical and laboratory parameters indicate a maximum inflammatory response at d11 of each cycle. Interestingly, the soluble IL-2 receptor remained increased at baseline of the next cycle indicating immune activation over the entire treatment period of 6 months.

CONCLUSIONS

LTI of ch14.18/CHO combined with s.c.IL-2 shows an improved tolerance in subsequent cycles allowing outpatient treatment.