Phase I study of vincristine, irinotecan, and ¹³¹I-metaiodobenzylguanidine for patients with relapsed or refractory neuroblastoma: a new approaches to neuroblastoma therapy trial

Phase II study of 131 I-metaiodobenzylguanidine with 5 days of topotecan for refractory or relapsed neuroblastoma: Results of the French study MIITOP

PURPOSE

We report the results of the French multicentric phase II study MIITOP (NCT00960739), which evaluated tandem infusions of 131 I-metaiodobenzylguanidine (mIBG) and topotecan in children with relapsed/refractory metastatic neuroblastoma (NBL).

METHODS

Patients received 131 I-mIBG on day 1, with intravenous topotecan daily on days 1-5. A second activity of 131 I-mIBG was given on day 21 to deliver a whole-body radiation dose of 4 Gy, combined with a second course of topotecan on days 21-25. Peripheral blood stem cells were infused on day 31.

RESULTS

Thirty patients were enrolled from November 2008 to June 2015. Median age at diagnosis was 5.5 years (2-20). Twenty-one had very high-risk NBL (VHR-NBL), that is, stage 4 NBL at diagnosis or at relapse, with insufficient response (i.e., less than a partial response of metastases and more than three mIBG spots) after induction chemotherapy; nine had progressive metastatic relapse. Median Curie score at inclusion was 6 (1-26). Median number of prior lines of treatment was 3 (1-7). Objective response rate was 13% (95% confidence interval [CI]: 4-31) for the whole population, 19% for VHR-NBL, and 0% for progressive relapses. Immediate tolerance was good, with nonhematologic toxicity limited to grade-2 nausea/vomiting in eight patients. Two-year event-free survival was 17% (95% CI: 6-32). Among the 16 patients with VHR-NBL who had not received prior myeloablative busulfan-melphalan consolidation, 13 had at least stable disease after MIITOP; 11 subsequently received busulfan-melphalan; four of them were alive (median follow-up: 7 years).

CONCLUSION

MIITOP showed acceptable tolerability in this heavily pretreated population and encouraging survival rates in VHR-NBL when followed by busulfan-melphalan.

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.

Current Status and Future Perspective on Molecular Imaging and Treatment of Neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in children and arises from anywhere along the sympathetic nervous system. It is a highly heterogeneous disease with a wide range of prognosis, from spontaneous regression or maturing to highly aggressive. About half of pediatric neuroblastoma patients develop the metastatic disease at diagnosis, which carries a poor prognosis. Nuclear medicine plays a pivotal role in the diagnosis, staging, response assessment, and long-term follow-up of neuroblastoma. And it has also played a prominent role in the treatment of neuroblastoma. Because the structure of metaiodobenzylguanidine (MIBG) is similar to that of norepinephrine, 90% of neuroblastomas are MIBG-avid. 123I-MIBG whole-body scintigraphy is the standard nuclear imaging technique for neuroblastoma, usually in combination with SPECT/CT. However, approximately 10% of neuroblastomas are MIBG nonavid. PET imaging has many technical advantages over SPECT imaging, such as higher spatial and temporal resolution, higher sensitivity, superior quantitative capability, and whole-body tomographic imaging. In recent years, various tracers have been used for imaging neuroblastoma with PET. The importance of patient-specific targeted radionuclide therapy for neuroblastoma therapy has also increased. 131I-MIBG therapy is part of the front-line treatment for children with high-risk neuroblastoma. And peptide receptor radionuclide therapy with radionuclide-labeled somatostatin analogues has been successfully used in the therapy of neuroblastoma. Moreover, radioimmunoimaging has important applications in the diagnosis of neuroblastoma, and radioimmunotherapy may provide a novel treatment modality against neuroblastoma. This review discusses the use of current and novel radiopharmaceuticals in nuclear medicine imaging and therapy of neuroblastoma.

Clinical Advances and Perspectives in Targeted Radionuclide Therapy

Targeted radionuclide therapy has become increasingly prominent as a nuclear medicine subspecialty. For many decades, treatment with radionuclides has been mainly restricted to the use of iodine-131 in thyroid disorders. Currently, radiopharmaceuticals, consisting of a radionuclide coupled to a vector that binds to a desired biological target with high specificity, are being developed. The objective is to be as selective as possible at the tumor level, while limiting the dose received at the healthy tissue level. In recent years, a better understanding of molecular mechanisms of cancer, as well as the appearance of innovative targeting agents (antibodies, peptides, and small molecules) and the availability of new radioisotopes, have enabled considerable advances in the field of vectorized internal radiotherapy with a better therapeutic efficacy, radiation safety and personalized treatments. For instance, targeting the tumor microenvironment, instead of the cancer cells, now appears particularly attractive. Several radiopharmaceuticals for therapeutic targeting have shown clinical value in several types of tumors and have been or will soon be approved and authorized for clinical use. Following their clinical and commercial success, research in that domain is particularly growing, with the clinical pipeline appearing as a promising target. This review aims to provide an overview of current research on targeting radionuclide therapy.

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.

Modulation of Radiation Biomarkers in a Randomized Phase II Study of 131I-MIBG With or Without Radiation Sensitizers for Relapsed or Refractory Neuroblastoma

PURPOSE

¹³¹I-metaiodobenzylguanidine (¹³¹I-MIBG) has demonstrated efficacy as a single agent in neuroblastoma. Recent trials have focused on ¹³¹I-MIBG combination strategies, though little is known about the effect of putative radiosensitizers on biological markers of radiation exposure.

METHODS AND MATERIALS

NANT2011-01 evaluated ¹³¹I-MIBG therapy alone (arm A) or in combination with vincristine/irinotecan (arm B) or vorinostat (arm C) for patients with relapsed or refractory neuroblastoma. Blood samples were collected before and after ¹³¹I-MIBG infusion to determine levels of radiation-associated biomarkers (transcript and protein). The association of biomarker with treatment arm, clinical response, and treatment toxicity was analyzed.

RESULTS

The cohort included 99 patients who had at least 1 biomarker available for analysis. Significant modulation in most biomarkers between baseline, 72, and 96 hours following ¹³¹I-MIBG was observed. Patients in arm C had the lowest degree of modulation in FLT3 ligand protein. Lower baseline BCL2 transcript levels were associated with higher overall response. Patients with greater increases in FLT3 ligand at 96 hours after ¹³¹I-MIBG therapy were significantly more likely to have grade 4 thrombocytopenia. Peripheral blood gene expression of the BCL2 family of apoptotic markers (BCL2L1 and BAX transcripts) was significantly associated with grade 4 hematologic toxicity. RNA sequencing demonstrated little overlap in the top modulated peripheral blood transcripts between randomized arms.

CONCLUSIONS

Peripheral blood biomarkers relevant to radiation exposure demonstrate significant modulation after ¹³¹I-MIBG and concomitant radiation sensitizers affect extent of modulation. Biomarkers related to hematopoietic damage and apoptosis were associated with hematologic toxicity.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Peripheral Blood Transcript Signatures after Internal 131I-mIBG Therapy in Relapsed and Refractory Neuroblastoma Patients Identifies Early and Late Biomarkers of Internal 131I Exposures

131I-metaiodobenzylguanidine (131I-mIBG) is a targeted radiation therapy developed for the treatment of advanced neuroblastoma. We have previously shown that this patient cohort can be used to predict absorbed dose associated with early 131I exposure, 72 h after treatment. We now expand these studies to identify gene expression differences associated with 131I-mIBG exposure 15 days after treatment. Total RNA from peripheral blood lymphocytes was isolated from 288 whole blood samples representing 59 relapsed or refractory neuroblastoma patients before and after 131I-mIBG treatment. We found that several transcripts predictive of early exposure returned to baseline levels by day 15, however, selected transcripts did not return to baseline. At 72 h, all 17 selected pathway-specific transcripts were differentially expressed. Transcripts CDKN1A (P < 0.000001), FDXR (P < 0.000001), DDB2 (P < 0.000001), and BBC3 (P < 0.000001) showed the highest up-regulation at 72 h after 131I-mIBG exposure, with mean log2 fold changes of 2.55, 2.93, 1.86 and 1.85, respectively. At day 15 after 131I-mIBG, 11 of the 17 selected transcripts were differentially expressed, with XPC, STAT5B, PRKDC, MDM2, POLH, IGF1R, and SGK1 displaying significant up-regulation at 72 h and significant down-regulation at day 15. Interestingly, transcripts FDXR (P = 0.01), DDB2 (P = 0.03), BCL2 (P = 0.003), and SESN1 (P < 0.0003) maintained differential expression 15 days after 131I-mIBG treatment. These results suggest that transcript levels for DNA repair, apoptosis, and ionizing radiation-induced cellular stress are still changing by 15 days after 131I-mIBG treatment. Our studies showcase the use of biodosimetry gene expression panels as predictive biomarkers following early (72 h) and late (15 days) internal 131I exposure. Our findings also demonstrate the utility of our transcript panel to differentiate exposed from non-exposed individuals up to 15 days after exposure from internal 131I.

Anatomic patterns of relapse and progression following treatment with 131 I-MIBG in relapsed or refractory neuroblastoma

OBJECTIVES

Patients with metaiodobenzylguanidine (MIBG)-avid relapsed or refractory neuroblastoma after initial therapy may exhibit transient responses to salvage treatment with iodine-131 metaiodobenzylguanidine (¹³¹ I-MIBG). It is unclear whether disease progression following ¹³¹ I-MIBG treatment occurs in previously involved versus new anatomic sites of disease. Understanding this pattern of relapse will inform the use of consolidation therapy following ¹³¹ I-MIBG administration.

METHODS

Patients with relapsed or refractory metastatic MIBG-avid neuroblastoma or ganglioneuroblastoma, who received single-agent ¹³¹ I-MIBG, had stable or responding disease 6-8 weeks following ¹³¹ I-MIBG, but subsequently experienced disease progression were included. MIBG scans were reviewed to establish anatomic and temporal evolution of MIBG-avid disease.

RESULTS

A total of 84 MIBG-avid metastatic sites were identified immediately prior to MIBG therapy in a cohort of 12 patients. At first progression, a total of 101 MIBG-avid sites were identified, of which 69 (68%) overlapped with pre-treatment disease sites, while 32 (32%) represented anatomically new disease areas. Eight of 12 patients had one or more new MIBG-avid sites at first progression. Of the 69 involved sites at progression that overlapped with pre-treatment disease, 11 represented relapsed sites that had cleared following MIBG therapy, two were persistent but increasingly MIBG-avid, and 56 were stably persistent.

CONCLUSIONS

Previously involved anatomic disease sites predominate at disease progression following ¹³¹ I-MIBG treatment. Nevertheless, the majority of patients progressed in at least one new anatomic disease site. This suggests that consolidation focal therapies targeting residual disease sites may be of limited benefit in preventing systemic disease progression following ¹³¹ I-MIBG treatment of relapsed or refractory neuroblastoma.

Randomized Phase II Trial of MIBG Versus MIBG, Vincristine, and Irinotecan Versus MIBG and Vorinostat for Patients With Relapsed or Refractory Neuroblastoma: A Report From NANT Consortium

PURPOSE

131I-metaiodobenzylguanidine (MIBG) is an active radiotherapeutic for neuroblastoma. The primary aim of this trial was to identify which of three MIBG regimens was likely associated with the highest true response rate.

PATIENTS AND METHODS

Patients 1-30 years were eligible if they had relapsed or refractory neuroblastoma, at least one MIBG-avid site, and adequate autologous stem cells. Patients received MIBG 18 mCi/kg on day 1 and autologous stem cell on day 15. Patients randomly assigned to arm A received only MIBG; patients randomly assigned to arm B received intravenous vincristine on day 0 and irinotecan daily on days 0-4; patients randomly assigned to arm C received vorinostat (180 mg/m2/dose) orally once daily on days 1 to 12. The primary end point was response after one course by New Approaches to Neuroblastoma Therapy criteria. The trial was designed with 105 patients to ensure an 80% chance that the arm with highest response rate was selected.

RESULTS

One hundred fourteen patients were enrolled, with three ineligible and six unevaluable, leaving 105 eligible and evaluable patients (36 in arm A, 35 in arm B, and 34 in arm C; 55 boys; and median age 6.5 years). After one course, the response rates (partial response or better) on arms A, B, and C were 14% (95% CI, 5 to 30), 14% (5 to 31), and 32% (18 to 51). An additional five, five, and four patients met New Approaches to Neuroblastoma Therapy Minor Response criteria on arms A, B, and C, respectively. On arms A, B, and C, rates of any grade 3+ nonhematologic toxicity after first course were 19%, 49%, and 35%.

CONCLUSION

Vorinostat and MIBG is likely the arm with the highest true response rate, with manageable toxicity. Vincristine and irinotecan do not appear to improve the response rate to MIBG and are associated with increased toxicity.

Phase 1 study of sorafenib and irinotecan in pediatric patients with relapsed or refractory solid tumors

BACKGROUND

Sorafenib,an orally bioavailable, multitarget tyrosine kinase inhibitor, and irinotecan, a topoisomerase I inhibitor, have demonstrated activity in pediatric and adult malignancies. We evaluated the toxicity, pharmacokinetic (PK), and pharmacogenomic (PGX) profile of sorafenib with irinotecan in children with relapsed or refractory solid tumors and assessed the feasibility of incorporating patient-reported outcome (PRO) measures as an adjunct to traditional endpoints.

METHODS

Sorafenib, continuous oral twice daily dosing, was administered with irinotecan, orally, once daily days 1-5, repeated every 21 days (NCT01518413). Based on tolerability, escalation of sorafenib followed by escalation of irinotecan was planned. Three patients were initially enrolled at each dose level. Sorafenib and irinotecan PK analyses were performed during cycle 1. PRO measurements were collected during cycles 1 and 2.

RESULTS

Fifteen patients were evaluable. Two of three patients at dose level 2 experienced dose-limiting toxicity (DLT), grade 3 diarrhea, and grade 3 hyponatremia. Therefore, dose level 1 was expanded to 12 patients and two patients had DLT, grade 4 thrombocytopenia, grade 3 elevated lipase. Nine of 15 (60%) patients had a best response of stable disease with four patients receiving ≥6 cycles.

CONCLUSIONS

The recommended dose for pediatric patients was sorafenib 150 mg/m² /dose twice daily with irinotecan 70 mg/m² /dose daily × 5 days every 21 days. This oral outpatient regimen was well tolerated and resulted in prolonged disease stabilization. There were no significant alterations in the PK profile of either agent when administered in combination. Patients were willing and able to report their subjective experiences with this regimen.

[Short-term effect of intensity-modulated radiotherapy for children with high-risk neuroblastoma: an analysis of 24 cases]

OBJECTIVE

To study the efficacy and safety of intensity-modulated radiotherapy (IMRT) in children with high-risk neuroblastoma (NB).

METHODS

A retrospective analysis was performed on the medical data of 24 children with high-risk NB who were diagnosed and treated with IMRT in the Department of Hematology and Oncology, Hunan Provincial People's Hospital, from April 2018 to December 2020. The medical data included age, radiotherapy dose, times of radiotherapy, laboratory examination results, adverse reactions, and survival.

RESULTS

All 24 children (14 boys and 10 girls) received IMRT, with a mean age of (65±23) months and a median age of 59 months. The primary tumor was located in the abdomen in 23 children and 1 child had primary tumor in the mediastinum. The median age was 41.5 months at the time of radiotherapy. The radiation dose of radiotherapy ranged from 14.4 to 36.0 Gy, with a mean dose of (22±3) Gy and a daily dose of 1.8-2.0 Gy. The radiotherapy was performed for a total number of 8-20 times, with a mean number of 11.9 times. Among these children, 6 received radiotherapy for the residual or metastatic lesion. Of all the 23 children, 3 experienced cough, 2 experienced diarrhea, and 1 experienced vomiting during radiotherapy. At 2 weeks after radiotherapy, serum creatinine ranged from 2.3 to 70.1 μmol/L and alanine aminotransferase ranged from 9.1 to 65.3 μ/L. Ten children experienced grade Ⅲ bone marrow suppression and 2 experienced grade Ⅳ bone marrow suppression 1 to 2 weeks after radiotherapy. Four children experienced grade Ⅲ bone marrow suppression and 1 experienced grade Ⅳ bone marrow suppression 3 to 4 weeks after radiotherapy. During a median follow-up time of 13.5 months, 23 children (96%) achieved stable disease and 1 died. Up to the follow-up date, second malignant tumor or abnormal organ function was not observed.

CONCLUSIONS

IMRT can improve the local control rate of NB. IMRT appears to be safe in the treatment of children with NB.

Combination radionuclide therapy: A new paradigm

Targeted molecular radionuclide therapy (MRT) has shown its potential for the treatment of cancers of multiple origins. A combination therapy strategy employing two or more distinct therapeutic approaches in cancer management is aimed at circumventing tumor resistance by simultaneously targeting compensatory signaling pathways or bypassing survival selection mutations acquired in response to individual monotherapies. Combination radionuclide therapy (CRT) is a newer application of the concept, utilizing a combination of radiolabeled molecular targeting agents with chemotherapy and beam radiation therapy for enhanced therapeutic index. Encouraging results are reported with chemotherapeutic agents in combination with radiolabeled targeting molecules for cancer therapy. With increasing awareness of the various survival and stress response pathways activated after radionuclide therapy, different holistic combinations of MRT agents with radiosensitizers targeting such pathways have also been explored. MRT has also been studied in combination with beam radiotherapy modalities such as external beam radiation therapy and carbon ion radiation therapy to enhance the anti-tumor response. Nanotechnology aids in CRT by bringing together multiple monotherapies on a single nanostructure platform for treating cancers in a more precise or personalized way. CRT will be a key player in managing cancers if correctly tailored to the individual patient profile. The success of CRT lies in an in-depth understanding of the radiobiological principles and pathways activated in response.

Iodine-131 metaiodobenzylguanidine (131I-mIBG) treatment in relapsed/refractory neuroblastoma

BACKGROUND

I-meta-iodo-benzylguanidine (I-mIBG) therapy has been used in treatment of for advanced neuroblastoma for many years with promising results. There are several studies regarding predictors and outcomes of I-mIBG therapies in relapsed/refractory neuroblastoma patients.

OBJECTIVE

To identify the predictors and outcomes of I-mIBG treatment in relapsed/refractory neuroblastoma.

METHODS

This study was a retrospective review of 22 patients with high risk stage IV relapsed/refractory neuroblastoma who received at least one cycle of I-mIBG therapy. Patient' characteristics, hematologic toxicity, scintigraphic semi-quantitative scoring, and overall survival were recorded. Factors predicting survival were analyzed.

RESULTS

Twenty-two patients (50% male) with mean age of 3.7 years (4.8 months to 8.3 years) received I-mIBG therapies at an average of 3.8 and mean dose of 136 mCi (5032 MBq) per treatment. Most common acute hematologic toxicity was thrombocytopenia. Overall 5-year survival rate was 37% (95% confidence interval: 16.3-58.0) and median survival time was 2.8 year (95% confidence interval: 1.38-6.34). Patients with rising Curie score of ≥25% upon the second therapy were major determinants of overall survival with poorer response to treatment. At least three treatments of I-mIBG were needed to identify some degrees of survival prolongation (crude hazard ratio: P-value = 0.003). Age, sex, metastatic status, and baseline Curie scoring system were good predictors associated with survival. Seven patients (32%) demonstrated objective responses.

CONCLUSION

Despite multimodality therapy, high risk neuroblastoma had a propensity of treatment failure in terms of relapsed or refractory, with some objective responses after I-mIBG treatments. The declined or non-rising Curie score upon second post-treatment total body scan was an important predictor of survival and aided a decision whether or not to proceed with bone marrow transplantation.

Peripheral Stem Cell Apheresis is Feasible Post 131Iodine-Metaiodobenzylguanidine-Therapy in High-Risk Neuroblastoma, but Results in Delayed Platelet Reconstitution

PURPOSE

Targeted radiotherapy with ¹³¹iodine-meta-iodobenzylguanidine (¹³¹I-MIBG) is effective for neuroblastoma (NBL), although optimal scheduling during high-risk (HR) treatment is being investigated. We aimed to evaluate the feasibility of stem cell apheresis and study hematologic reconstitution after autologous stem cell transplantation (ASCT) in patients with HR-NBL treated with upfront ¹³¹I-MIBG-therapy.

EXPERIMENTAL DESIGN

In two prospective multicenter cohort studies, newly diagnosed patients with HR-NBL were treated with two courses of ¹³¹I-MIBG-therapy, followed by an HR-induction protocol. Hematopoietic stem and progenitor cell (e.g., CD34⁺ cell) harvest yield, required number of apheresis sessions, and time to neutrophil (>0.5 × 10⁹/L) and platelet (>20 × 10⁹/L) reconstitution after ASCT were analyzed and compared with "chemotherapy-only"-treated patients. Moreover, harvested CD34⁺ cells were functionally (viability and clonogenic capacity) and phenotypically (CD33, CD41, and CD62L) tested before cryopreservation (n = 44) and/or after thawing (n = 19).

RESULTS

Thirty-eight patients (47%) were treated with ¹³¹I-MIBG-therapy, 43 (53%) only with chemotherapy. Median cumulative ¹³¹I-MIBG dose/kg was 0.81 GBq (22.1 mCi). Median CD34⁺ cell harvest yield and apheresis days were comparable in both groups. Post ASCT, neutrophil recovery was similar (11 days vs. 10 days), whereas platelet recovery was delayed in ¹³¹I-MIBG- compared with chemotherapy-only-treated patients (29 days vs. 15 days, P = 0.037). Testing of harvested CD34⁺ cells revealed a reduced post-thaw viability in the ¹³¹I-MIBG-group. Moreover, the viable CD34⁺ population contained fewer cells expressing CD62L (L-selectin), a marker associated with rapid platelet recovery.

CONCLUSIONS

Harvesting of CD34⁺ cells is feasible after ¹³¹I-MIBG. Platelet recovery after ASCT was delayed in ¹³¹I-MIBG-treated patients, possibly due to reinfusion of less viable and CD62L-expressing CD34⁺ cells, but without clinical complications. We provide evidence that peripheral stem cell apheresis is feasible after upfront ¹³¹I-MIBG-therapy in newly diagnosed patients with NBL. However, as the harvest of ¹³¹I-MIBG-treated patients contained lower viable CD34⁺ cell counts after thawing and platelet recovery after reinfusion was delayed, administration of ¹³¹I-MIBG after apheresis is preferred.

Neuroblastoma

Neuroblastoma is one of the most common solid tumors in children and has a diverse clinical behavior that largely depends on the tumor biology. Neuroblastoma exhibits unique features, such as early age of onset, high frequency of metastatic disease at diagnosis in patients over 1 year of age and the tendency for spontaneous regression of tumors in infants. The high-risk tumors frequently have amplification of the MYCN oncogene as well as segmental chromosome alterations with poor survival. Recent advanced genomic sequencing technology has revealed that mutation of ALK, which is present in ~10% of primary tumors, often causes familial neuroblastoma with germline mutation. However, the frequency of gene mutations is relatively small and other aberrations, such as epigenetic abnormalities, have also been proposed. The risk-stratified therapy was introduced by the Japan Neuroblastoma Study Group (JNBSG), which is now moving to the Neuroblastoma Committee of Japan Children's Cancer Group (JCCG). Several clinical studies have facilitated the reduction of therapy for children with low-risk neuroblastoma disease and the significant improvement of cure rates for patients with intermediate-risk as well as high-risk disease. Therapy for patients with high-risk disease includes intensive induction chemotherapy and myeloablative chemotherapy, followed by the treatment of minimal residual disease using differentiation therapy and immunotherapy. The JCCG aims for better cures and long-term quality of life for children with cancer by facilitating new approaches targeting novel driver proteins, genetic pathways and the tumor microenvironment.

Current Consensus on I-131 MIBG Therapy

Metaiodobenzylguanidine (MIBG) is structurally similar to the neurotransmitter norepinephrine and specifically targets neuroendocrine cells including some neuroendocrine tumors. Iodine-131 (I-131)-labeled MIBG (I-131 MIBG) therapy for neuroendocrine tumors has been performed for more than a quarter-century. The indications of I-131 MIBG therapy include treatment-resistant neuroblastoma (NB), unresectable or metastatic pheochromocytoma (PC) and paraganglioma (PG), unresectable or metastatic carcinoid tumors, and unresectable or metastatic medullary thyroid cancer (MTC). I-131 MIBG therapy is one of the considerable effective treatments in patients with advanced NB, PC, and PG. On the other hand, I-131 MIBG therapy is an alternative method after more effective novel therapies are used such as radiolabeled somatostatin analogs and tyrosine kinase inhibitors in patients with advanced carcinoid tumors and MTC. No-carrier-aided (NCA) I-131 MIBG has more favorable potential compared to the conventional I-131 MIBG. Astatine-211-labeled meta-astatobenzylguanidine (At-211 MABG) has massive potential in patients with neuroendocrine tumors. Further studies about the therapeutic protocols of I-131 MIBG including NCA I-131 MIBG in the clinical setting and At-211 MABG in both the preclinical and clinical settings are needed.

Predictors of response, progression-free survival, and overall survival using NANT Response Criteria (v1.0) in relapsed and refractory high-risk neuroblastoma

PURPOSE

The New Approaches to Neuroblastoma Therapy Response Criteria (NANTRC) were developed to optimize response assessment in patients with recurrent/refractory neuroblastoma. Response predictors and associations of the NANTRC version 1.0 (NANTRCv1.0) and prognostic factors with outcome were analyzed.

METHODS

A retrospective analysis was performed of patients with recurrent/refractory neuroblastoma enrolled from 2000 to 2009 on 13 NANT Phase 1/2 trials. NANTRC overall response integrated CT/MRI (Response Evaluation Criteria in Solid Tumors [RECIST]), metaiodobenzylguanidine (MIBG; Curie scoring), and percent bone marrow (BM) tumor (morphology).

RESULTS

Fourteen (6.9%) complete response (CR) and 14 (6.9%) partial response (PR) occurred among 203 patients evaluable for response. Five-year progression-free survival (PFS) was 16 ± 3%; overall survival (OS) was 27 ± 3%. Disease sites at enrollment included MIBG-avid lesions (100% MIBG trials; 84% non-MIBG trials), measurable CT/MRI lesions (48%), and BM (49%). By multivariable analysis, Curie score of 0 (P < 0.001), lower Curie score (P = 0.003), no measurable CT/MRI lesions (P = 0.044), and treatment on peripheral blood stem cell (PBSC) supported trials (P = 0.005) were associated with achieving CR/PR. Overall response of stable disease (SD) or better was associated with better OS (P < 0.001). In multivariable analysis, MYCN amplification (P = 0.037) was associated with worse PFS; measurable CT/MRI lesions (P = 0.041) were associated with worse OS; prior progressive disease (PD; P < 0.001/P < 0.001), Curie score ≥ 1 (P < 0.001; P = 0.001), higher Curie score (P = 0.048/0.037), and treatment on non-PBSC trials (P = < 0.001/0.003) were associated with worse PFS and OS.

CONCLUSIONS

NANTRCv1.0 response of at least SD is associated with better OS in patients with recurrent/refractory neuroblastoma. Patient and tumor characteristics may predict response and outcome. Identifying these variables can optimize Phase 1/2 trial design to select novel agents for further testing.

Assessment of Organ Dosimetry for Planning Repeat Treatments of High-Dose 131I-MIBG Therapy: 123I-MIBG Versus Posttherapy 131I-MIBG Imaging

PURPOSE

To evaluate detailed organ-based radiation-absorbed dose for planning double high-dose treatment with I-MIBG.

METHODS

In a prospective study, 33 patients with high-risk refractory or recurrent neuroblastoma were treated with high-dose I-MIBG. Organ dosimetry was estimated from the first I-MIBG posttherapy imaging and from subsequent I-MIBG imaging prior to the planned second administration. Three serial whole-body scans were performed per patient 2 to 6 days after I-MIBG therapy (666 MBq/kg or 18 mCi/kg) and approximately 0.5, 24, and 48 hours after the diagnostic I-MIBG dose (370 MBq/kg or 10 mCi/1.73 m). Organ radiation doses were calculated using OLINDA. I-MIBG scan dosimetry estimations were used to predict doses for the second I-MIBG therapy and compared with I-MIBG posttherapy estimates.

RESULTS

Mean ± SD whole-body doses from I-MIBG and I-MIBG scans were 0.162 ± 112 and 0.141 ± 0.068 mGy/MBq, respectively. I-MIBG and I-MIBG organ doses were variable-generally higher for I-MIBG-projected doses than those projected using posttherapy I-MIBG scans. Mean ± SD doses to liver, heart wall, and lungs were 0.487 ± 0.28, 0.225 ± 0.20, and 0.40 ± 0.26, respectively, for I-MIBG and 0.885 ± 0.56, 0.618 ± 0.37, and 0.458 ± 0.56, respectively, for I-MIBG. Mean ratio of I-MIBG to I-MIBG estimated radiation dose was 1.81 ± 1.95 for the liver, 2.75 ± 1.84 for the heart, and 1.13 ± 0.93 for the lungs. No unexpected toxicities were noted based on I-MIBG-projected doses and cumulative dose limits of 30, 20, and 15 Gy to liver, kidneys, and lungs, respectively.

CONCLUSIONS

For repeat I-MIBG treatment planning, both I-MIBG and I-MIBG imaging yielded variable organ doses. However, I-MIBG-based dosimetry yielded a more conservative estimate of maximum allowable activity and would be suitable for planning and limiting organ toxicity with repeat high-dose therapies.

The small molecule inhibitor YK-4-279 disrupts mitotic progression of neuroblastoma cells, overcomes drug resistance and synergizes with inhibitors of mitosis

Neuroblastoma is a biologically and clinically heterogeneous pediatric malignancy that includes a high-risk subset for which new therapeutic agents are urgently required. As well as MYCN amplification, activating point mutations of ALK and NRAS are associated with high-risk and relapsing neuroblastoma. As both ALK and RAS signal through the MEK/ERK pathway, we sought to evaluate two previously reported inhibitors of ETS-related transcription factors, which are transcriptional mediators of the Ras-MEK/ERK pathway in other cancers. Here we show that YK-4-279 suppressed growth and triggered apoptosis in nine neuroblastoma cell lines, while BRD32048, another ETV1 inhibitor, was ineffective. These results suggest that YK-4-279 acts independently of ETS-related transcription factors. Further analysis reveals that YK-4-279 induces mitotic arrest in prometaphase, resulting in subsequent cell death. Mechanistically, we show that YK-4-279 inhibits the formation of kinetochore microtubules, with treated cells showing a broad range of abnormalities including multipolar, fragmented and unseparated spindles, together leading to disrupted progression through mitosis. Notably, YK-4-279 does not affect microtubule acetylation, unlike the conventional mitotic poisons paclitaxel and vincristine. Consistent with this, we demonstrate that YK-4-279 overcomes vincristine-induced resistance in two neuroblastoma cell-line models. Furthermore, combinations of YK-4-279 with vincristine, paclitaxel or the Aurora kinase A inhibitor MLN8237/Alisertib show strong synergy, particularly at low doses. Thus, YK-4-279 could potentially be used as a single-agent or in combination therapies for the treatment of high-risk and relapsing neuroblastoma, as well as other cancers.

Combination of bevacizumab, irinotecan, and temozolomide for refractory or relapsed neuroblastoma: Results of a phase II study

BACKGROUND

The rationale for studying the combination of bevacizumab, irinotecan, and temozolomide (BIT) in neuroblastoma (NB) is based on the following: (i) vascular endothelial growth factor (VEGF) expression is associated with an aggressive phenotype, (ii) anti-VEGF antibody bevacizumab enhances irinotecan-mediated suppression of NB xenografts, (iii) bevacizumab safety has been established in pediatric phase I studies, and (iv) irinotecan + temozolomide (IT) is a standard salvage chemotherapy.

PROCEDURE

We conducted a phase II study of BIT in patients with measurable/evaluable refractory or relapsed high-risk NB (www.clinicaltrials.gov, NCT01114555). Each cycle consisted of bevacizumab (15 mg/kg intravenously [IV]) on days 1 and 15 plus irinotecan (50 mg/m2 /day IV) and temozolomide (150 mg/m2 /day orally) on days 4-8. Patients could have previously received, but not relapsed on, IT. An early stopping rule mandated continuing therapy only if more than five patients of 27 evaluable patients achieved partial response (PR) or complete response (CR) after four cycles.

RESULTS

Thirty-three heavily pretreated patients (nine primary refractory; 24 relapsed) received one to eight cycles of BIT. Toxicities were expected and transient. Grade 4 toxicities were neutropenia (30%) and thrombocytopenia (24%). Grade 3 toxicities included hepatic transaminitis (15%), proteinuria (9%), and diarrhea (3%). Overall responses were as follows: three CR (all in prior IT-treated patients), 18 no response, and 12 progressive disease. Only one of 23 patients assessable for the early stopping rule regarding efficacy achieved PR/CR, so patient accrual was discontinued. Median progression-free survival and overall survival was 7.7 ± 1.7 and 31.5 ± 5.6 months, respectively; all patients continued anti-NB therapy post-BIT.

CONCLUSIONS

BIT was well tolerated, but the addition of bevacizumab did not improve response rates in resistant NB compared to historical data for IT.

Optimization of liposomal topotecan for use in treating neuroblastoma

The purpose of this work was to develop an optimized liposomal formulation of topotecan for use in the treatment of patients with neuroblastoma. Drug exposure time studies were used to determine that topotecan (Hycamtin) exhibited great cytotoxic activity against SK-N-SH, IMR-32 and LAN-1 neuroblastoma human cell lines. Sphingomyelin (SM)/cholesterol (Chol) and 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)/Chol liposomes were prepared using extrusion methods and then loaded with topotecan by pH gradient and copper-drug complexation. In vitro studies showed that SM/Chol liposomes retained topotecan significantly better than DSPC/Chol liposomes. Decreasing the drug-to-lipid ratio engendered significant increases in drug retention. Dose-range finding studies on NRG mice indicated that an optimized SM/Chol liposomal formulation of topotecan prepared with a final drug-to-lipid ratio of 0.025 (mol: mol) was better tolerated than the previously described DSPC/Chol topotecan formulation. Pharmacokinetic studies showed that the optimized SM/Chol liposomal topotecan exhibited a 10-fold increase in plasma half-life and a 1000-fold increase in AUC0-24 h when compared with Hycamtin administered at equivalent doses (5 mg/kg). In contrast to the great extension in exposure time, SM/Chol liposomal topotecan increased the life span of mice with established LAN-1 neuroblastoma tumors only modestly in a subcutaneous and systemic model. The extension in exposure time may still not be sufficient and the formulation may require further optimization. In the future, liposomal topotecan will be assessed in combination with high-dose radiotherapy such as 131 I-metaiodobenzylguanidine, and immunotherapy treatment modalities currently used in neuroblastoma therapy.

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.

Neuroblastoma

Neuroblastoma is the most common extracranial solid tumour occurring in childhood and has a diverse clinical presentation and course depending on the tumour biology. Unique features of these neuroendocrine tumours are the early age of onset, the high frequency of metastatic disease at diagnosis and the tendency for spontaneous regression of tumours in infancy. The most malignant tumours have amplification of the MYCN oncogene (encoding a transcription factor), which is usually associated with poor survival, even in localized disease. Although transgenic mouse models have shown that MYCN overexpression can be a tumour-initiating factor, many other cooperating genes and tumour suppressor genes are still under investigation and might also have a role in tumour development. Segmental chromosome alterations are frequent in neuroblastoma and are associated with worse outcome. The rare familial neuroblastomas are usually associated with germline mutations in ALK, which is mutated in 10-15% of primary tumours, and provides a potential therapeutic target. Risk-stratified therapy has facilitated the reduction of therapy for children with low-risk and intermediate-risk disease. Advances in therapy for patients with high-risk disease include intensive induction chemotherapy and myeloablative chemotherapy, followed by the treatment of minimal residual disease using differentiation therapy and immunotherapy; these have improved 5-year overall survival to 50%. Currently, new approaches targeting the noradrenaline transporter, genetic pathways and the tumour microenvironment hold promise for further improvements in survival and long-term quality of life.

Neuroblastoma (Peripheral neuroblastic tumours)

Peripheral neuroblastic tumours (PNTs), a family of tumours arising in the embryonal remnants of the sympathetic nervous system, account for 7-10% of all tumours in children. In two-thirds of cases, PNTs originate in the adrenal glands or the retroperitoneal ganglia. At least one third present metastases at onset, with bone and bone marrow being the most frequent metastatic sites. Disease extension, MYCN oncogene status and age are the most relevant prognostic factors, and their influence on outcome have been considered in the design of the recent treatment protocols. Consequently, the probability of cure has increased significantly in the last two decades. In children with localised operable disease, surgical resection alone is usually a sufficient treatment, with 3-year event-free survival (EFS) being greater than 85%. For locally advanced disease, primary chemotherapy followed by surgery and/or radiotherapy yields an EFS of around 75%. The greatest problem is posed by children with metastatic disease or amplified MYCN gene, who continue to do badly despite intensive treatments. Ongoing trials are exploring the efficacy of new drugs and novel immunological approaches in order to save a greater number of these patients.

Pharmacogenomics in Pediatric Oncology: Review of Gene-Drug Associations for Clinical Use

During the 3rd congress of the European Society of Pharmacogenomics and Personalised Therapy (ESPT) in Budapest in 2015, a preliminary meeting was held aimed at establishing a pediatric individualized treatment in oncology and hematology committees. The main purpose was to facilitate the transfer and harmonization of pharmacogenetic testing from research into clinics, to bring together basic and translational research and to educate health professionals throughout Europe. The objective of this review was to provide the attendees of the meeting as well as the larger scientific community an insight into the compiled evidence regarding current pharmacogenomics knowledge in pediatric oncology. This preliminary evaluation will help steer the committee’s work and should give the reader an idea at which stage researchers and clinicians are, in terms of personalizing medicine for children with cancer. From the evidence presented here, future recommendations to achieve this goal will also be suggested.

Transcript Analysis for Internal Biodosimetry Using Peripheral Blood from Neuroblastoma Patients Treated with (131)I-mIBG, a Targeted Radionuclide

Calculating internal dose from therapeutic radionuclides currently relies on estimates made from multiple radiation exposure measurements, converted to absorbed dose in specific organs using the Medical Internal Radiation Dose (MIRD) schema. As an alternative biodosimetric approach, we utilized gene expression analysis of whole blood from patients receiving targeted radiotherapy. Collected blood from patients with relapsed or refractory neuroblastoma who received (131)I-labeled metaiodobenzylguanidine ((131)I-mIBG) at the University of California San Francisco (UCSF) was used to compare calculated internal dose with the modulation of chosen gene expression. A total of 40 patients, median age 9 years, had blood drawn at baseline, 72 and 96 h after (131)I-mIBG infusion. Whole-body absorbed dose was calculated for each patient based on the cumulated activity determined from injected mIBG activity and patient-specific time-activity curves combined with (131)I whole-body S factors. We then assessed transcripts that were the most significant for describing the mixed therapeutic treatments over time using real-time polymerase chain reaction (RT-PCR). Modulation was evaluated statistically using multiple regression analysis for data at 0, 72 and 96 h. A total of 10 genes were analyzed across 40 patients: CDKN1A; FDXR; GADD45A; BCLXL; STAT5B; BAX; BCL2; DDB2; XPC; and MDM2. Six genes were significantly modulated upon exposure to (131)I-mIBG at 72 h, as well as at 96 h. Four genes varied significantly with absorbed dose when controlling for time. A gene expression biodosimetry model was developed to predict absorbed dose based on modulation of gene transcripts within whole blood. Three transcripts explained over 98% of the variance in the modulation of gene expression over the 96 h (CDKN1A, BAX and DDB2). To our knowledge, this is a novel study, which uses whole blood collected from patients treated with a radiopharmaceutical, to characterize biomarkers that may be useful for biodosimetry. Our data indicate that transcripts, which have been previously identified as biomarkers of external exposures in ex vivo whole blood and in vivo radiotherapy patients, are also good early indicators of internal exposure. However, for internal sources of radiation, the biokinetics and physical decay of the radionuclide strongly influence the gene expression.

Individualized 131I-mIBG therapy in the management of refractory and relapsed neuroblastoma

OBJECTIVE

Iodine-131-labelled meta-iodobenzylguanidine (I-mIBG) therapy is an established treatment modality for relapsed/refractory neuroblastoma, most frequently administered according to fixed or weight-based criteria. We evaluate response and toxicity following a dosimetry-based, individualized approach.

MATERIALS AND METHODS

A review of 44 treatments in 25 patients treated with I-mIBG therapy was performed. Patients received I-mIBG therapy following relapse (n=9), in refractory disease (n=12), or with surgically unresectable disease despite conventional treatment (n=4). Treatment schedule (including mIBG dose and number of administrations) was individualized according to the clinical status of the patient and dosimetry data from either a tracer study or previous administrations. Three-dimensional tumour dosimetry was also performed for eight patients.

RESULTS

The mean administered activity was 11089±7222 MBq and the mean whole-body dose for a single administration was 1.79±0.57 Gy. Tumour-absorbed doses varied considerably (3.70±3.37 mGy/MBq). CTCAE grade 3/4 neutropenia was documented following 82% treatments and grade 3/4 thrombocytopenia following 71% treatments. Further acute toxicity was found in 49% of patients. All acute toxicities resolved with appropriate therapy. The overall response rate was 58% (complete or partial response), with a further 29% of patients having stable disease.

CONCLUSION

A highly personalized approach combining patient-specific dosimetry and clinical judgement enables delivery of high activities that can be tolerated by patients, particularly with stem cell support. We report excellent response rates and acceptable toxicity following individualized I-mIBG therapy.

Impact of Whole-Body Radiation Dose on Response and Toxicity in Patients With Neuroblastoma After Therapy With 131 I-Metaiodobenzylguanidine (MIBG)

BACKGROUND

(131) I-metaiodobenzylguanidine ((131) I-MIBG) is a targeted radiopharmaceutical for patients with neuroblastoma. Despite its tumor-specific uptake, the treatment with (131) I-MIBG results in whole-body radiation exposure. Our aim was to correlate whole-body radiation dose (WBD) from (131) I-MIBG with tumor response, toxicities, and other clinical factors.

METHODS

This retrospective cohort analysis included 213 patients with high-risk neuroblastoma treated with (131) I-MIBG at UCSF Benioff Children's Hospital between 1996 and 2015. WBD was determined from radiation exposure rate measurements. The relationship between WBD ordered tertiles and variables were analyzed using Cochran-Mantel-Haenszel test of trend, Kruskal-Wallis test, and one-way analysis of variance. Correlation between WBD and continuous variables was analyzed using Pearson correlation and Spearman rank correlation.

RESULTS

WBD correlated with (131) I-MIBG administered activity, particularly with (131) I-MIBG per kilogram (P < 0.001). Overall response rate did not differ significantly among the three tertiles of WBD. Correlation between response by relative Curie score and WBD was of borderline significance, with patients receiving a lower WBD showing greater reduction in osteomedullary metastases by Curie score (rs = 0.16, P = 0.049). There were no significant ordered trends among tertiles in any toxicity measures (grade 4 neutropenia, thrombocytopenia < 20,000/μl, and grade > 1 hypothyroidism).

CONCLUSIONS

This study showed that (131) I-MIBG activity per kilogram correlates with WBD and suggests that activity per kilogram will predict WBD in most patients. Within the range of activities prescribed, there was no correlation between WBD and either response or toxicity. Future studies should evaluate tumor dosimetry, rather than just WBD, as a tool for predicting response following therapy with (131) I-MIBG.

Arsenic Trioxide as a Radiation Sensitizer for 131I-Metaiodobenzylguanidine Therapy: Results of a Phase II Study

Arsenic trioxide has in vitro and in vivo radiosensitizing properties. We hypothesized that arsenic trioxide would enhance the efficacy of the targeted radiotherapeutic agent (131)I-metaiodobenzylguanidine ((131)I-MIBG) and tested the combination in a phase II clinical trial.

METHODS

Patients with recurrent or refractory stage 4 neuroblastoma or metastatic paraganglioma/pheochromocytoma (MP) were treated using an institutional review board-approved protocol (Clinicaltrials.gov identifier NCT00107289). The planned treatment was (131)I-MIBG (444 or 666 MBq/kg) intravenously on day 1 plus arsenic trioxide (0.15 or 0.25 mg/m(2)) intravenously on days 6-10 and 13-17. Toxicity was evaluated using National Cancer Institute Common Toxicity Criteria, version 3.0. Response was assessed by International Neuroblastoma Response Criteria or (for MP) by changes in (123)I-MIBG or PET scans.

RESULTS

Twenty-one patients were treated: 19 with neuroblastoma and 2 with MP. Fourteen patients received (131)I-MIBG and arsenic trioxide, both at maximal dosages; 2 patients received a 444 MBq/kg dose of (131)I-MIBG plus a 0.15 mg/kg dose of arsenic trioxide; and 3 patients received a 666 MBq/kg dose of (131)I-MIBG plus a 0.15 mg/kg dose of arsenic trioxide. One did not receive arsenic trioxide because of transient central line-induced cardiac arrhythmia, and another received only 6 of 10 planned doses of arsenic trioxide because of grade 3 diarrhea and vomiting with concurrent grade 3 hypokalemia and hyponatremia. Nineteen patients experienced myelosuppression higher than grade 2, most frequently thrombocytopenia (n = 18), though none required autologous stem cell rescue. Twelve of 13 evaluable patients experienced hyperamylasemia higher than grade 2 from transient sialoadenitis. By International Neuroblastoma Response Criteria, 12 neuroblastoma patients had no response and 7 had progressive disease, including 6 of 8 entering the study with progressive disease. Objective improvements in semiquantitative (131)I-MIBG scores were observed in 6 patients. No response was seen in MP. Seventeen of 19 neuroblastoma patients continued on further chemotherapy or immunotherapy. Mean 5-year overall survival (±SD) for neuroblastoma was 37% ± 11%. Mean absorbed dose of (131)I-MIBG to blood was 0.134 cGy/MBq, well below myeloablative levels in all patients.

CONCLUSION

(131)I-MIBG plus arsenic trioxide was well tolerated, with an adverse event profile similar to that of (131)I-MIBG therapy alone. The addition of arsenic trioxide to (131)I-MIBG did not significantly improve response rates when compared with historical data with (131)I-MIBG alone.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Advances in Risk Classification and Treatment Strategies for Neuroblastoma

Risk-based treatment approaches for neuroblastoma have been ongoing for decades. However, the criteria used to define risk in various institutional and cooperative groups were disparate, limiting the ability to compare clinical trial results. To mitigate this problem and enhance collaborative research, homogenous pretreatment patient cohorts have been defined by the International Neuroblastoma Risk Group classification system. During the past 30 years, increasingly intensive, multimodality approaches have been developed to treat patients who are classified as high risk, whereas patients with low- or intermediate-risk neuroblastoma have received reduced therapy. This treatment approach has resulted in improved outcome, although survival for high-risk patients remains poor, emphasizing the need for more effective treatments. Increased knowledge regarding the biology and genetic basis of neuroblastoma has led to the discovery of druggable targets and promising, new therapeutic approaches. Collaborative efforts of institutions and international cooperative groups have led to advances in our understanding of neuroblastoma biology, refinements in risk classification, and stratified treatment strategies, resulting in improved outcome. International collaboration will be even more critical when evaluating therapies designed to treat small cohorts of patients with rare actionable mutations.

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.

Iodine-131 metaiodobenzylguanidine therapy for neuroblastoma: reports so far and future perspective

Neuroblastoma, which derives from neural crest, is the most common extracranial solid cancer in childhood. The tumors express the norepinephrine (NE) transporters on their cell membrane and take in metaiodobenzylguanidine (MIBG) via a NE transporter. Since iodine-131 (I-131) MIBG therapy was firstly reported, many trails of MIBG therapy in patients with neuroblastoma were performed. Though monotherapy with a low dose of I-131 MIBG could achieve high-probability pain reduction, the objective response was poor. In contrast, more than 12 mCi/kg I-131 MIBG administrations with or without hematopoietic cell transplantation (HCT) obtain relatively good responses in patients with refractory or relapsed neuroblastoma. The combination therapy with I-131 MIBG and other modalities such as nonmyeloablative chemotherapy and myeloablative chemotherapy with HCT improved the therapeutic response in patients with refractory or relapsed neuroblastoma. In addition, I-131 MIBG therapy incorporated in the induction therapy was proved to be feasible in patients with newly diagnosed neuroblastoma. To expand more the use of MIBG therapy for neuroblastoma, further studies will be needed especially in the use at an earlier stage from diagnosis, in the use with other radionuclide formations of MIBG, and in combined use with other therapeutic agents.

Phase I Study of Vorinostat as a Radiation Sensitizer with 131I-Metaiodobenzylguanidine (131I-MIBG) for Patients with Relapsed or Refractory Neuroblastoma

PURPOSE

(131)I-metaiodobenzylguanidine (MIBG) is a radiopharmaceutical with activity in neuroblastoma. Vorinostat is a histone deacetylase inhibitor that has radiosensitizing properties. The goal of this phase I study was to determine the MTDs of vorinostat and MIBG in combination.

EXPERIMENTAL DESIGN

Patients ≤ 30 years with relapsed/refractory MIBG-avid neuroblastoma were eligible. Patients received oral vorinostat (dose levels 180 and 230 mg/m(2)) daily days 1 to 14. MIBG (dose levels 8, 12, 15, and 18 mCi/kg) was given on day 3 and peripheral blood stem cells on day 17. Alternating dose escalation of vorinostat and MIBG was performed using a 3+3 design.

RESULTS

Twenty-seven patients enrolled to six dose levels, with 23 evaluable for dose escalation. No dose-limiting toxicities (DLT) were seen in the first three dose levels. At dose level 4 (15 mCi/kg MIBG/230 mg/m(2) vorinostat), 1 of 6 patients had DLT with grade 4 hypokalemia. At dose level 5 (18 mCi/kg MIBG/230 mg/m(2) vorinostat), 2 patients had dose-limiting bleeding (one grade 3 and one grade 5). At dose level 5a (18 mCi/kg MIBG/180 mg/m(2) vorinostat), 0 of 6 patients had DLT. The most common toxicities were neutropenia and thrombocytopenia. The response rate was 12% across all dose levels and 17% at dose level 5a. Histone acetylation increased from baseline in peripheral blood mononuclear cells collected on days 3 and 12 to 14.

CONCLUSIONS

Vorinostat at 180 mg/m(2)/dose is tolerable with 18 mCi/kg MIBG. A phase II trial comparing this regimen to single-agent MIBG is ongoing.

Phase I/II study of (131)I-MIBG with vincristine and 5 days of irinotecan for advanced neuroblastoma

Background:

¹³¹I-metaiodobenzylguanidine (MIBG) is an active radiopharmaceutical in neuroblastoma. A previous study demonstrated that MIBG could be combined with vincristine and prolonged irinotecan, although 25% of first courses had grade 3 diarrhoea. The current phase I/II study evaluated MIBG with vincristine and 5 days of higher-dose irinotecan.

Methods:

Patients 1–30 years old with advanced neuroblastoma were eligible. Patients received cefixime on days −1 to +6, irinotecan (50 mg m⁻² per dose IV) on days 0–4, vincristine (2 mg m⁻²) on day 0, MIBG (555 or 666 MBq kg⁻¹) on day 1, and peripheral blood stem cells on day 13. UGT1A1 genotyping was performed in consenting patients.

Results:

Thirty-two patients (12 phase I ; 20 phase II) received 42 courses. No dose-limiting toxicities were seen during dose escalation and the recommended administered activity was 666 MBq kg⁻¹. Myelosuppression and diarrhoea were the most common toxicities, with grade 3 diarrhoea in 6% of first courses. Patients homozygous for UGT1A1*28 had more grade 4 thrombocytopenia (80% vs 37% P=0.14). Responses (five complete and four partial) occurred in 9 out of 32 (28%) patients.

Conclusions:

MIBG (666 MBq kg⁻¹) with vincristine and this irinotecan schedule is tolerable and active, with less severe diarrhoea compared with a regimen using more protracted irinotecan.

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.

[Childhood cancer: progress but prognosis still very unequal. Example of Retinoblastoma and high-risk Neuroblastoma]

Children suffering with cancer have a higher probability of cure than adult. Since the 1950's, high cure rates have been achieved following remarkable progress in the overall care of these children. Not only children are more often "cured" than during the past century but they are probably "better cured" with the hope of experiencing less late effects. Nevertheless, there are still large disparities related to tumor diagnosis and regional area on the globe. If retinoblastoma is now cured in about 100% of the cases in industrialized countries, a different figure is seen unfortunately in economically disadvantaged countries. Not only is access to primary care lower, but also ophthalmologic techniques and available cancer treatments are less effective. Nowadays, such high cure rates observed for children with retinoblastoma are not the rule for all children with cancer. For example, despite considerable progress with new innovative treatments, the cure rate of children with metastatic neuroblastoma does not exceed 40%.

Advances in paediatric cancer treatment

Four out of five children diagnosed with cancer can be cured with contemporary cancer therapy. This represents a dramatic improvement since 50 years ago when the cure rate of childhood cancer was <25% in the pre-chemotherapy era. Over the past ten years, while improvement in overall survival (OS) has been marginal, progress in pediatric oncology lies with adopting risk-adapted therapeutic approach. This has been made possible through identifying clinical and biologic prognostic factors with rigorous research and stratifying patients using these risk factors, and subsequently modifying therapy according to risk group assignment. This review provides a perspective for eight distinct pediatric malignancies, in which significant advances in treatment were made in the last decade and are leading to changes in standard of care. This includes four hematologic malignancies [acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL)] and four solid tumors [medulloblastoma (MB), low grade glioma (LGG), neuroblastoma (NB) and Ewing sarcoma (ES)]. Together, they comprise 60% of childhood cancer. Improved patient outcome is not limited to better survival, but encompasses reducing both short and long-term treatment-related complications which is as important as cure, given the majority of childhood cancer patients will become long-term survivors. Risk-adapted approach allows treatment intensification in the high-risk cohort while therapy can be de-escalated in the low-risk to minimize toxicity and late sequelae without compromising survival. Advances in medical research technology have also led to a rapid increase in the understanding of the genetics of childhood cancer in the last decade, facilitating identification of molecular targets that can potentially be exploited for therapeutic benefits. As we move into the era of targeted therapeutics, searching for novel agents that target specific genetic lesions becomes a major research focus. We provide an overview of seven novel agents (bevacizumab, bortezomib, vorinostat, sorafenib, tipifarnib, erlotinib and mTOR inhibitors), which have been most frequently pursued in childhood cancers in the last decade, as well as reporting the progress of clinical trials involving these agents.

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.

Acute changes in blood pressure in patients with neuroblastoma treated with ¹³¹I-metaiodobenzylguanidine (MIBG)

BACKGROUND

Iodine-131-metaiodobenzylguanidine ((131)I-MIBG) provides targeted radiotherapy for children with neuroblastoma. The aim of our study was to evaluate systematically the acute effects of (131)I-MIBG on blood pressure in patients with neuroblastoma and to identify possible predictors of hypertension.

PROCEDURE

We conducted a retrospective chart review of neuroblastoma patients who were treated with (131)I-MIBG between January 1, 1999 and June 1, 2012 at the University of California, San Francisco. Clinical data for 172 patients with neuroblastoma, receiving 218 administrations of (131)I-MIBG, were collected. The primary endpoint was development of systolic blood pressure above the 95th percentile for age. Logistic regression with generalized estimating equations to account for multiple administrations in some subjects was used to identify bivariate and multivariate predictors of hypertension.

RESULTS

Of the 218 administrations of (131)I-MIBG, 112 (51.3%) were associated with at least one episode of systolic hypertension during or after the (131)I-MIBG infusion. The majority of these acute elevations in blood pressure resolved within 48 hours of the infusion. Only six administrations in five patients required nifedipine administration to lower blood pressure. Younger age (P = 0.012), lower eGFR (P = 0.047), and elevated blood pressure measurements immediately before infusion began (P = 0.010) were all independently associated with risk of treatment-associated hypertension.

CONCLUSIONS

Acute elevations in blood pressure are common after therapeutic doses of (131) I-MIBG. Elevations in blood pressure typically occur only within the first 48 hours after (131)I-MIBG administration. Blood pressure monitoring during this period of risk is recommended.

Children's Oncology Group's 2013 blueprint for research: neuroblastoma

Estimated 5-year survival rates for patients with non-high-risk and high-risk neuroblastoma are 90% and 50%, respectively. Recent clinical trials have shown excellent outcomes with reduced therapy for non-high-risk disease. For patients with high-risk neuroblastoma treated with chemoradiotherapy, surgery, and stem cell transplantation, the addition of anti-disialoganglioside (GD2) immunotherapy plus cytokines improves survival. Upcoming trials will study the incorporation of targeted radionuclide therapy prior to myeloablative chemotherapy into high-risk treatment. Phase 2 trials will investigate druggable target(s) including mTOR inhibition and GD2-directed therapy in combination with chemotherapy for patients with recurrent neuroblastoma, and ALK inhibition for those with ALK-aberrant tumors.