131I-metaiodobenzylguanidine (131I-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 131I-MIBG between patients with relapsed and treatment-refractory neuroblastoma.
This was a retrospective cohort analysis of 218 patients with refractory or relapsed neuroblastoma treated with 131I-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.
The response rate (complete and partial response) to 131I-MIBG-based therapies for all patients was 27%. There was no difference in response rates between relapsed and refractory patients. However, after 131I-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% 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).
Although there was no significant difference in overall response rates to 131I-MIBG between patients with relapsed vs. refractory neuroblastoma, patients with prior relapse had higher rates of progressive disease and had lower 2-year overall survival after 131I-MIBG compared to patients with refractory disease.
neuroblastoma; 131I-MIBG; pediatric; radionuclide; relapse; refractory
The International Neuroblastoma Risk Group (INRG) classification system was developed to establish a consensus approach for pretreatment risk stratification. Because the International Neuroblastoma Staging System (INSS) is a postsurgical staging system, a new clinical staging system was required for the INRG pretreatment risk classification system.
To stage patients before any treatment, the INRG Task Force, consisting of neuroblastoma experts from Australia/New Zealand, China, Europe, Japan, and North America, developed a new INRG staging system (INRGSS) based on clinical criteria and image-defined risk factors (IDRFs). To investigate the impact of IDRFs on outcome, survival analyses were performed on 661 European patients with INSS stages 1, 2, or 3 disease for whom IDRFs were known.
In the INGRSS, locoregional tumors are staged L1 or L2 based on the absence or presence of one or more of 20 IDRFs, respectively. Metastatic tumors are defined as stage M, except for stage MS, in which metastases are confined to the skin, liver, and/or bone marrow in children younger than 18 months of age. Within the 661-patient cohort, IDRFs were present (ie, stage L2) in 21% of patients with stage 1, 45% of patients with stage 2, and 94% of patients with stage 3 disease. Patients with INRGSS stage L2 disease had significantly lower 5-year event-free survival than those with INRGSS stage L1 disease (78% ± 4% v 90% ± 3%; P = .0010).
Use of the new staging (INRGSS) and risk classification (INRG) of neuroblastoma will greatly facilitate the comparison of risk-based clinical trials conducted in different regions of the world.
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.
We assessed the long-term outcome of patients enrolled on CCG-3891, a high-risk neuroblastoma study in which patients were randomly assigned to undergo autologous purged bone marrow transplantation (ABMT) or to receive chemotherapy, and subsequent treatment with 13-cis-retinoic acid (cis-RA).
Patients and Methods
Patients received the same induction chemotherapy, with random assignment (N = 379) to consolidation with myeloablative chemotherapy, total-body irradiation, and ABMT versus three cycles of intensive chemotherapy. Patients who completed consolidation without disease progression were randomly assigned to receive no further therapy or cis-RA for 6 months.
The event-free survival (EFS) for patients randomly assigned to ABMT was significantly higher than those randomly assigned to chemotherapy; the 5-year EFS (mean ± SE) was 30% ± 4% versus 19% ± 3%, respectively (P = .04). The 5-year EFS (42% ± 5% v 31% ± 5%) from the time of second random assignment was higher for cis-RA than for no further therapy, though it was not significant. Overall survival (OS) was significantly higher for each random assignment by a test of the log(−log(.)) transformation of the survival estimates at 5 years (P < .01). The 5-year OS from the second random assignment of patients who underwent both random assignments and who were assigned to ABMT/cis-RA was 59% ± 8%; for ABMT/no cis-RA, it was 41% ± 7%; for continuing chemotherapy/cis-RA, it was 38% ± 7%; and for chemotherapy/no cis-RA, it was 36% ± 7%.
Myeloablative therapy and autologous hematopoietic cell rescue result in significantly better 5-year EFS and OS than nonmyeloablative chemotherapy; cis-RA given after consolidation independently results in significantly improved OS.
Recurrence of high-risk neuroblastoma is common despite multimodality therapy. ch14.18, a chimeric human/murine anti-GD2 antibody, lyses neuroblastoma cells. This study determined the maximum tolerable dose (MTD) and toxicity of ch14.18 given in combination with interleukin-2 (IL-2) after high-dose chemotherapy (HDC)/stem-cell rescue (SCR). Biologic correlates including ch14.18 levels, soluble IL-2 receptor levels, and human antichimeric antibody (HACA) activity were evaluated.
Patients and Methods
Patients were given ch14.18 for 4 days at 28-day intervals. Patients received IL-2 during the second and fourth courses of ch14.18 and granulocyte-macrophage colony-stimulating factor (GM-CSF) during the first, third, and fifth courses. The MTD was determined based on toxicities occurring with the second course. After the determination of the MTD, additional patients were treated to confirm the MTD and to clarify appropriate supportive care.
Twenty-five patients were enrolled. The MTD of ch14.18 was determined to be 25 mg/m2/d for 4 days given concurrently with 4.5 × 106 U/m2/d of IL-2 for 4 days. IL-2 was also given at a dose of 3 × 106 U/m2/d for 4 days starting 1 week before ch14.18. Two patients experienced dose-limiting toxicity due to ch14.18 and IL-2. Common toxicities included pain, fever, nausea, emesis, diarrhea, urticaria, mild elevation of hepatic transaminases, capillary leak syndrome, and hypotension. No death attributable to toxicity of therapy occurred. No additional toxicity was seen when cis-retinoic acid (cis-RA) was given between courses of ch14.18. No patient treated at the MTD developed HACA.
ch14.18 in combination with IL-2 was tolerable in the early post-HDC/SCR period. cis-RA can be administered safely between courses of ch14.18 and cytokines.
Neuroblastoma (NB) is a heterogeneous tumor arising from sympathetic tissues. The impact of primary tumor site in influencing the heterogeneity of NB remains unclear.
Patients and Methods
Children younger than age 21 years diagnosed with NB or ganglioneuroblastoma between 1990 and 2002 and with known primary site were identified from the International Neuroblastoma Risk Group database. Data were compared between sites with respect to clinical and biologic features, as well as event-free survival (EFS) and overall survival (OS).
Among 8,369 children, 47% had adrenal tumors. All evaluated clinical and biologic variables differed statistically between primary sites. The features that were > 10% discrepant between sites were stage 4 disease, MYCN amplification, elevated ferritin, elevated lactate dehydrogenase, and segmental chromosomal aberrations, all of which were more frequent in adrenal versus nonadrenal tumors (P < .001). Adrenal tumors were more likely than nonadrenal tumors (adjusted odds ratio, 2.09; 95% CI, 1.67 to 2.63; P < .001) and thoracic tumors were less likely than nonthoracic tumors (adjusted odds ratio, 0.20; 95% CI, 0.11 to 0.39; P < .001) to have MYCN amplification after controlling for age, stage, and histologic grade. EFS and OS differed significantly according to the primary site (P < .001 for both comparisons). After controlling for age, MYCN status, and stage, patients with adrenal tumors had higher risk for events (hazard ratio, 1.13 compared with nonadrenal tumors; 95% CI, 1.03 to 1.23; P = .008), and patients with thoracic tumors had lower risk for events (HR, 0.79 compared with nonthoracic; 95% CI, 0.67 to 0.92; P = .003).
Clinical and biologic features show important differences by NB primary site, with adrenal and thoracic sites associated with inferior and superior survival, respectively. Future studies will need to investigate the biologic origin of these differences.
Patients with neuroblastoma younger than 12 months of age with a 4S pattern of disease (metastases limited to liver, skin, bone marrow) have better outcomes than infants with stage 4 disease. The new International Neuroblastoma Risk Group (INRG) staging system extends age to 18 months for the 4S pattern. Our aim was to determine which prognostic features could be used for optimal risk classification among patients younger than 18 months with metastatic disease.
Event-free survival (EFS) and overall survival were analyzed by log-rank tests, Cox models, and survival tree regression for 656 infants with stage 4S neuroblastoma younger than 12 months of age and 1,019 patients with stage 4 disease younger than 18 months of age in the INRG database.
Unfavorable biologic features were more frequent in infants with stage 4 disease than in infants with 4S tumors and higher overall in those age 12 to 18 months (although not different for stage 4 v 4S pattern). EFS was significantly better for infants younger than 12 months with 4S pattern than with stage 4 disease (P < .01) but similar for toddlers age 12 to 18 months with stage 4 versus 4S pattern. Among 717 patients with stage 4S pattern, patients age 12 to 18 months had worse EFS than those age younger than 12 months (P < .01). MYCN, 11q, mitosis-karyorrhexis index (MKI), ploidy, and lactate dehydrogenase were independently statistically significant predictors of EFS and more highly predictive than age or metastatic pattern. MYCN, 11q, MKI, histology, and 1p were combined in a survival tree for improved risk stratification.
Tumor biology is more critical than age or metastatic pattern for prognosis of patients age younger than 18 months with metastatic neuroblastoma and should be considered for risk stratification.
131I-metaiodobenzylguanidine (MIBG) is a radiopharmaceutical with activity in neuroblastoma. Vorinostat is a histone deacetylase inhibitor that has radiosensitizing properties. The goal of this phase 1 study was to determine the maximum tolerated doses of vorinostat and MIBG in combination.
Patients ≤ 30 years with relapsed/refractory MIBG-avid neuroblastoma were eligible. Patients received oral vorinostat (dose levels 180 and 230 mg/m2) daily Days 1–14. 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.
27 patients enrolled to 6 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/m2 vorinostat), 1 of 6 patients had DLT with grade 4 hypokalemia. At dose level 5 (18 mCi/kg MIBG/230 mg/m2 vorinostat), two patients had dose-limiting bleeding (one grade 3 and one grade 5). At dose level 5a (18 mCi/kg MIBG/180 mg/m2 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 12–14.
Vorinostat at 180 mg/m2/dose is tolerable with 18 mCi/kg MIBG. A phase 2 trial comparing this regimen to single-agent MIBG is ongoing.
131I-MIBG; Vorinostat; Radiation Sensitizer; Neuroblastoma; Relapse; Refractory
Sarcomas are a heterogeneous group of mesenchymal malignancies. In recent years, studies have demonstrated that inhibition of angiogenic pathways or disruption of established vasculature can attenuate the growth of sarcomas. However, when used as monotherapy in the clinical setting, these targeted antiangiogenic agents have only provided modest survival benefits in some sarcoma subtypes, and have not been efficacious in others. Preclinical and early clinical data suggest that the addition of conventional chemotherapy to antiangiogenic agents may lead to more effective therapies for patients with these tumors. In the current review, the authors summarize the available evidence and possible mechanisms supporting this approach.
Sarcoma; Antiangiogenesis; Combination drug therapy; Combination chemotherapy
Iodine-131-m-iodobenzylguanidine ([131I]mIBG) targeted radionuclide therapy (TRT) is a standard treatment for recurrent or refractory neuroblastoma with response rates of 30–40%. The aim of this study is to demonstrate patient-specific dosimetry using quantitative [124I]mIBG PET/CT imaging with a Geant4-based Monte Carlo method for better treatment planning.
A Monte Carlo dosimetry method was developed using the Geant4 toolkit with voxelized anatomical geometry and source distribution as input. The pre-segmented hybrid computational human phantoms developed by the University of Florida and the National Cancer Institute (UF/NCI) were used as a surrogate to characterize the anatomy of a given patient. S-values for I-131 were estimated by the phantoms coupled with Geant4 and compared with those estimated by OLINDA|EXM and MCNPX for the newborn model. To obtain patient-specific biodistribution of [131I]mIBG, a 10-year-old girl with relapsed neuroblastoma was imaged with [124I]mIBG PET/CT at four time points prior to the planned [131I]mIBG TRT. The organ and tumor absorbed dose of the clinical case were estimated with the Geant4 method using the modified UF/NCI 10-year-old phantom with tumors and the patient-specific residence time.
For the newborn model, the Geant4 S-values were consistent with the MCNPX S- values. The S-value ratio of the Geant4 method to OLINDA|EXM ranged from 0.08 to 6.5 of all major organs. The [131I]mIBG residence time quantified from the pretherapy [124I]mIBG PET/CT imaging of the 10-year-old patient was mostly comparable to those previously reported. Organ absorbed dose for the salivary glands were 98.0 Gy, heart wall, 36.5 Gy, and liver, 34.3 Gy; while tumor absorbed dose ranged from 143.9 Gy to 1641.3 Gy in different sites.
Patient-specific dosimetry for [131I]mIBG targeted radionuclide therapy was accomplished using pretherapy [124I]mIBG PET/CT imaging and a Geant4-based Monte Carlo dosimetry method. The Geant4 method with quantitative pretherapy imaging can provide dose estimates to normal organs and tumors with more realistic simulation geometry, and thus may improve treatment planning for [131I]mIBG TRT.
neuroblastoma; [131I]-m-iodobenzylguanidine; targeted radionuclide therapy; [124I]mIBG PET/CT imaging; dosimetry; Monte Carlo simulation
The presence of distant metastases is one of the most powerful predictors of outcome in patients with neuroblastoma. However, the pattern of metastatic spread is not incorporated into current risk stratification systems. Small case series have suggested that patients with neuroblastoma who have metastatic disease limited to distant lymph nodes (4N disease) may have improved outcomes.
Patients and Methods
We analyzed retrospective data from the International Neuroblastoma Risk Group database for patients diagnosed from 1990 to 2002. 4N patients were compared with the remaining stage 4 patients (non-4N), excluding those with missing metastatic site data.
In all, 2,250 International Neuroblastoma Staging System stage 4 patients with complete data were identified, of whom 146 (6.5%) had 4N disease. For 4N patients, event-free survival (EFS; 5-year, 77% ± 4%) and overall survival (OS; 5-year, 85% ± 3%) were significantly better than EFS (5-year, 35% ± 1%) and OS (5-year, 42% ± 1%) for non-4N stage 4 patients (P < .001). 4N patients were more likely to be younger (P < .001) and have tumors with favorable characteristics, including absence of MYCN amplification (89% v 69%; P < .001). In a multivariable analysis, 4N disease remained a significant predictor of outcome (hazard ratio for non-4N v 4N: 3.40 for EFS and 3.69 for OS). Within subgroups defined by age at diagnosis and tumor MYCN status, 4N disease was significantly associated with improved outcomes.
4N represents a subgroup with better outcome than that of other patients with metastatic disease. These findings suggest that the biology and treatment response of 4N tumors differ from other stage 4 tumors, and less intensive therapy should be considered for this cohort. Future exploration of biologic factors determining the pattern of metastatic spread is warranted.
Children diagnosed at age ≥ 18 months with metastatic MYCN-nonamplified neuroblastoma (NBL-NA) are at high risk for disease relapse, whereas those diagnosed at age < 18 months are nearly always cured. In this study, we investigated the hypothesis that expression of genes related to tumor-associated inflammatory cells correlates with the observed differences in survival by age at diagnosis and contributes to a prognostic signature.
Tumor-associated macrophages (TAMs) in localized and metastatic neuroblastomas (n = 71) were assessed by immunohistochemistry. Expression of 44 genes representing tumor and inflammatory cells was quantified in 133 metastatic NBL-NAs to assess age-dependent expression and to develop a logistic regression model to provide low- and high-risk scores for predicting progression-free survival (PFS). Tumors from high-risk patients enrolled onto two additional studies (n = 91) served as independent validation cohorts.
Metastatic neuroblastomas had higher infiltration of TAMs than locoregional tumors, and metastatic tumors diagnosed in patients at age ≥ 18 months had higher expression of inflammation-related genes than those in patients diagnosed at age < 18 months. Expression of genes representing TAMs (CD33/CD16/IL6R/IL10/FCGR3) contributed to 25% of the accuracy of a novel 14-gene tumor classification score. PFS at 5 years for children diagnosed at age ≥ 18 months with NBL-NA with a low- versus high-risk score was 47% versus 12%, 57% versus 8%, and 50% versus 20% in three independent clinical trials, respectively.
These data suggest that interactions between tumor and inflammatory cells may contribute to the clinical metastatic neuroblastoma phenotype, improve prognostication, and reveal novel therapeutic targets.
The primary objective of Children's Oncology Group study P9641 was to demonstrate that surgery alone would achieve 3-year overall survival (OS) ≥ 95% for patients with asymptomatic International Neuroblastoma Staging System stages 2a and 2b neuroblastoma (NBL). Secondary objectives focused on other low-risk patients with NBL and on those who required chemotherapy according to protocol-defined criteria.
Patients and Methods
Patients underwent maximally safe resection of tumor. Chemotherapy was reserved for patients with, or at risk for, symptomatic disease, with less than 50% tumor resection at diagnosis, or with unresectable progressive disease after surgery alone.
For all 915 eligible patients, 5-year event-free survival (EFS) and OS were 89% ± 1% and 97% ± 1%, respectively. For patients with asymptomatic stage 2a or 2b disease, 5-year EFS and OS were 87% ± 2% and 96% ± 1%, respectively. Among patients with stage 2b disease, EFS and OS were significantly lower for those with unfavorable histology or diploid tumors, and OS was significantly lower for those ≥ 18 months old. For patients with stage 1 and 4s NBL, 5-year OS rates were 99% ± 1% and 91% ± 1%, respectively. Patients who required chemotherapy at diagnosis achieved 5-year OS of 98% ± 1%. Of all patients observed after surgery, 11.1% experienced recurrence or progression of disease.
Excellent survival rates can be achieved in asymptomatic low-risk patients with stages 2a and 2b NBL after surgery alone. Immediate use of chemotherapy may be restricted to a minority of patients with low-risk NBL. Patients with stage 2b disease who are older or have diploid or unfavorable histology tumors fare less well. Future studies will seek to refine risk classification.
Neuroblastoma, the most common extra- cranial solid tumor in children, is derived from neural crest cells. Nearly half of patients present with metastatic disease, and have 5-year EFS of less than 50%. New approaches with targeted therapy may improve efficacy without increased toxicity. The current review will evaluate three promising targeted therapies, including 131I-metaiodobenzylguanidine (MIBG), a radiopharmaceutical taken up by the human norepinephrine transporter expressed in 90% of neuroblastomas, immunotherapy with monoclonal antibodies targeting the GD2 ganglioside, expressed on 98% of neuroblastoma cells, and inhibitors of ALK, a tyrosine kinase which is mutated or amplified in approximately 10% of neuroblastoma and expressed on the surface of most neuroblastoma cells. Early phase trials have confirmed the activity of 131I-MIBG in relapsed neuroblastoma, with response rates of about 30%, but the technical aspects of administration of large amounts of radioactivity in young children and the limited access have hindered incorporation into treatment of newly diagnosed patients. Anti-GD2 antibodies have also demonstrated activity in relapsed disease, and a recent phase III randomized trial showed a significant improvement in event-free survival for patients receiving chimeric anti-GD2 (ch14.18) combined with cytokines and isotretinoin after myeloablative consolidation therapy. A recently approved small molecule inhibitor of ALK has promising pre-clinical activity for neuroblastoma, and is currently in phase I and II trials. This is the first agent directed to a specific mutation in neuroblastoma, and marks a new step toward personalized therapy for neuroblastoma. Further clinical development of targeted treatments offers new hope for children with neuroblastoma.
To assess the feasibility of adding dose-intensive topotecan and cyclophosphamide to induction therapy for newly diagnosed high-risk neuroblastoma (HRNB).
Patients and Methods
Enrolled patients received two cycles of topotecan (approximately 1.2 mg/m2/d) and cyclophosphamide (400 mg/m2/d) for 5 days followed by four cycles of multiagent chemotherapy (Memorial Sloan-Kettering Cancer Center [MSKCC] regimen). Pharmacokinetically guided topotecan dosing (target systemic exposure with area under the curve of 50 to 70 ng/mL/hr) was performed. Peripheral-blood stem cell (PBSC) harvest and surgical resection of residual primary tumor occurred after cycles 2 and 5, respectively. Patients achieving at least a partial response received myeloablative chemotherapy with PBSC rescue and radiation to the presurgical primary tumor volume. Oral 13-cis-retinoic acid maintenance therapy was administered twice daily for 14 days in six 28-day cycles.
Thirty-one patients were enrolled onto the study. No deaths related to toxicity or dose-limiting toxicities occurred during induction. Mucositis rarely occurred after topotecan cycles (9.7%) in contrast to 30% after MSKCC cycles. Thirty patients underwent PBSC collection with median 31.1 × 106 CD34+ cells/kg (range, 1.8 to 541.8 × 106 CD34+ cells/kg), all negative for tumor contamination by immunocytochemical analysis. Targeted topotecan systemic exposure was achieved in 26 (84%) of 31 patients. At the end of induction, 26 patients (84%) had tumor response and one patient had progressive disease. In the overall cohort, 3-year event-free and overall survival were 37.8% ± 9.4% and 57.1% ± 9.4%, respectively.
This pilot induction regimen was well tolerated with expected and reversible toxicities. These data support investigation of efficacy in a phase III clinical trial for newly diagnosed HRNB.
Adolescent and adult patients with neuroblastoma appear to have a more indolent disease course but a lower survival than their younger counterparts. The majority of neuroblastoma tumors specifically accumulate the radiolabeled norepinephrine analogue 131I-metaiodobenzylguanidine (MIBG). 131I-MIBG has therefore become increasingly used as targeted radiotherapy for relapsed or refractory neuroblastoma. The aim of this study was to characterize the toxicity and activity of this therapy in older patients.
We performed a retrospective analysis of 39 consecutive patients ages 10 years and older with relapsed or refractory neuroblastoma who were treated with 131I-MIBG monotherapy at UCSF under Phase I, Phase II, and compassionate access protocols.
Sixteen patients were ≥18 years old at MIBG treatment initiation, whereas twenty-three were 10–17 years old. The median cumulative administered dose of 131I-MIBG was 17.8 mCi/kg. The majority of treatments led to grade 3 or 4 hematologic toxicities which were similar in frequency among age strata. Three patients subsequently developed hematologic malignancy or myelodysplasia. The overall rate of complete plus partial response was 46%. Patients ≥18 years old at time of first MIBG treatment had a significantly higher response rate compared to patients 10–17 years old (56% vs 39%, p=0.023). Median overall survival was 23 months with a trend toward longer overall survival for the ≥18 year old subgroup (p = 0.12).
Our findings suggest that 131I-MIBG is a highly effective salvage agent for adolescents and adults with neuroblastoma.
neuroblastoma; adult; adolescent; MIBG; radiopharmaceutical
Survival after neuroblastoma relapse is poor. Understanding the relationship between clinical and biologic features and outcome after relapse may help in selection of optimal therapy. Our aim was to determine which factors were significantly predictive of postrelapse overall survival (OS) in patients with recurrent neuroblastoma—particularly whether time from diagnosis to first relapse (TTFR) was a significant predictor of OS.
Patients and Methods
Patients with first relapse/progression were identified in the International Neuroblastoma Risk Group (INRG) database. Time from study enrollment until first event and OS time starting from first event were calculated. Cox regression models were used to calculate the hazard ratio of increased death risk and perform survival tree regression. TTFR was tested in a multivariable Cox model with other factors.
In the INRG database (N = 8,800), 2,266 patients experienced first progression/relapse. Median time to relapse was 13.2 months (range, 1 day to 11.4 years). Five-year OS from time of first event was 20% (SE, ± 1%). TTFR was statistically significantly associated with OS time in a nonlinear relationship; patients with TTFR of 36 months or longer had the lowest risk of death, followed by patients who relapsed in the period of 0 to less than 6 months or 18 to 36 months. Patients who relapsed between 6 and 18 months after diagnosis had the highest risk of death. TTFR, age, International Neuroblastoma Staging System stage, and MYCN copy number status were independently predictive of postrelapse OS in multivariable analysis.
Age, stage, MYCN status, and TTFR are significant prognostic factors for postrelapse survival and may help in the design of clinical trials evaluating novel agents.
123I-metaiodobenzylguanidine (MIBG) scans are preferable to 131I-MIBG for neuroblastoma imaging as they deliver less patient radiation yet have greater sensitivity in disease detection. Both 123I-MIBG and 131I-MIBG scans were used for disease assessments of neuroblastoma patients enrolled on Children’s Oncology Group (COG) high-risk study A3973. The hypothesis was that 123I-MIBG and 131I-MIBG scans were sufficiently similar for clinical purposes in terms of ability to predict survival.
Patients enrolled on COG A3973 with stage 4 disease who completed 123I-MIBG or 131I-MIBG scans at diagnosis, post-induction, post-transplant, or post-biotherapy were analyzed. The performance of the Curie score for each MIBG scan type in predicting survival was evaluated. At each time point, survival curves for 123I-MIBG versus 131I-MIBG were compared using the log-rank test.
Of the 413 patients on A3973 with at least one MIBG scan, 350 were stage 4. The 5-year event-free survival (EFS) and overall survival (OS) rates were 33.4 ± 3.6% and 45.6 ± 4.0% (N = 350). At post-induction, EFS (P = 0.3501) and OS (P = 0.5337) for 123I-MIBG versus 131I-MIBG were not significantly different. Similarly, comparisons at the three other time points were non-significant.
We found no evidence of a statistically significant difference in outcome by type of scan. For future survival analyses of MIBG Curie scores, 123I-MIBG and 131I-MIBG results may be combined and analyzed overall, without adjustment for scan type.
COG A3973; Curie score
131I-Metaiodobenzylguanidine (131I-MIBG) provides targeted radiotherapy for children with neuroblastoma, a malignancy of the sympathetic nervous system. Dissociated radioactive iodide may concentrate in the thyroid, and MIBG is concentrated in the liver after MIBG therapy. The aim of our study was to analyze the effects of 131I-MIBG therapy on thyroid and liver function.
Pre and post therapy thyroid and liver functions were reviewed in a total of 194 neuroblastoma patients treated with 131I-MIBG therapy. The cumulative incidence over time was estimated for both thyroid and liver toxicities. The relationship to cumulative dose/kg, number of treatments, time from treatment to follow-up, sex, and patient age was examined.
In patients who presented with Grade 0 or Grade 1 thyroid toxicity at baseline, 12±4% experienced onset or worsening to Grade 2 hypothyroidism and one patient developed Grade 2 hyperthyroidism by two years after 131I-MIBG therapy. At two years post 131I-MIBG therapy, 76±4% patients experienced onset or worsening of hepatic toxicity to any grade, and 23±5% experienced onset of or worsening to Grade 3 or 4 liver toxicity. Liver toxicity usually was transient asymptomatic transaminase elevation, frequently confounded by disease progression and other therapies.
The prophylactic regimen of potassium iodide and potassium perchlorate with 131I-MIBG therapy resulted in a low rate of significant hypothyroidism. Liver abnormalities following 131I-MIBG therapy were primarily reversible and did not result in late toxicity. 131I-MIBG therapy is a promising treatment for children with relapsed neuroblastoma with a relatively low rate of symptomatic thyroid or hepatic dysfunction.
Neuroblastoma; 131I-MIBG; Hypothyroidism
Iodine-131—metaiodobenzylguanidine (131I-MIBG) provides targeted radiotherapy with more than 30% response rate in refractory neuroblastoma, but activity infused is limited by radiation safety and hematologic toxicity. The goal was to determine the maximum-tolerated dose of 131I-MIBG in two consecutive infusions at a 2-week interval, supported by autologous stem-cell rescue (ASCR) 2 weeks after the second dose.
Patients and Methods
The 131I-MIBG dose was escalated using a 3 + 3 phase I trial design, with levels calculated by cumulative red marrow radiation index (RMI) from both infusions. Using dosimetry, the second infusion was adjusted to achieve the target RMI, except at level 4, where the second infusion was capped at 21 mCi/kg.
Twenty-one patients were enrolled onto the study at levels 1 to 4, with 18 patients assessable for toxicity and 20 patients assessable for response. Cumulative 131I-MIBG given to achieve the target RMI ranged from 22 to 50 mCi/kg, with cumulative RMI of 3.2 to 8.92 Gy. No patient had a dose-limiting toxicity. Reversible grade 3 nonhematologic toxicity occurred in six patients at level 4, establishing the recommended cumulative dose as 36 mCi/kg. The median time to absolute neutrophil count more than 500/μL after ASCR was 13 days (4 to 27 days) and to platelet independence was 17 days (6 to 47 days). Responses included two partial responses, eight mixed responses, three stable disease, and seven progressive disease. Responses by semiquantitative MIBG score occurred in eight patients, soft tissue responses occurred in five of 11 patients, but bone marrow responses occurred in only two of 13 patients.
The lack of toxicity with this approach allowed dramatic dose intensification of 131I-MIBG, with minimal toxicity and promising activity.
Treatment of patients with localized neuroblastoma with unfavorable biologic features is controversial. To evaluate the outcome of children with low-stage MYCN-amplified neuroblastoma and develop a rational treatment strategy, data from the International Neuroblastoma Risk Group (INRG) database were analyzed.
Patients and Methods
The database is comprised of 8,800 patients. Of these, 2,660 patients (30%) had low-stage (International Neuroblastoma Staging System stages 1 and 2) neuroblastoma, known MYCN status, and available follow-up data. Eighty-seven of these patients (3%) had MYCN amplified tumors.
Patients with MYCN-amplified, low-stage tumors had less favorable event-free survival (EFS) and overall survival (OS) than did patients with nonamplified tumors (53% ± 8% and 72% ± 7% v 90% ± 1% and 98% ± 1%, respectively). EFS and OS were statistically significantly higher for patients whose tumors were hyperdiploid rather than diploid (EFS, 82% ± 20% v 37% ± 21%; P = .0069; OS, 94% ± 11% v 54% ± 15%; P = .0056, respectively). No other variable had prognostic significance. Initial treatment consisted of surgery alone for 29 (33%) of 87 patients. Details of additional therapy were unknown for 14 patients. Twenty-two patients (25%) underwent surgery and moderate-intensity chemotherapy; another 22 underwent surgery, intensive chemotherapy, and radiation therapy. Nine of the latter 22 underwent stem cell transplantation. Survival in patients who received transplantation did not differ from survival in those who did not receive transplantation.
Among patients with low-stage, MYCN-amplified neuroblastoma, outcomes of patients with hyperdiploid tumors were statistically, significantly better than those with diploid tumors. The data suggest that tumor cell ploidy could potentially be used to identify candidates for reductions in therapy. Further study of MYCN-amplified, low-stage neuroblastoma is warranted.
Because current approaches to risk classification and treatment stratification for children with neuroblastoma (NB) vary greatly throughout the world, it is difficult to directly compare risk-based clinical trials. The International Neuroblastoma Risk Group (INRG) classification system was developed to establish a consensus approach for pretreatment risk stratification.
Patients and Methods
The statistical and clinical significance of 13 potential prognostic factors were analyzed in a cohort of 8,800 children diagnosed with NB between 1990 and 2002 from North America and Australia (Children's Oncology Group), Europe (International Society of Pediatric Oncology Europe Neuroblastoma Group and German Pediatric Oncology and Hematology Group), and Japan. Survival tree regression analyses using event-free survival (EFS) as the primary end point were performed to test the prognostic significance of the 13 factors.
Stage, age, histologic category, grade of tumor differentiation, the status of the MYCN oncogene, chromosome 11q status, and DNA ploidy were the most highly statistically significant and clinically relevant factors. A new staging system (INRG Staging System) based on clinical criteria and tumor imaging was developed for the INRG Classification System. The optimal age cutoff was determined to be between 15 and 19 months, and 18 months was selected for the classification system. Sixteen pretreatment groups were defined on the basis of clinical criteria and statistically significantly different EFS of the cohort stratified by the INRG criteria. Patients with 5-year EFS more than 85%, more than 75% to ≤ 85%, ≥ 50% to ≤ 75%, or less than 50% were classified as very low risk, low risk, intermediate risk, or high risk, respectively.
By defining homogenous pretreatment patient cohorts, the INRG classification system will greatly facilitate the comparison of risk-based clinical trials conducted in different regions of the world and the development of international collaborative studies.
Neuroblastoma is the most common pediatric extracranial solid cancer. This tumor is characterized by metaiodobenzylguanidine (MIBG) avidity in 90% of cases, prompting the use of radiolabeled MIBG for targeted radiotherapy in these tumors.
The available English language literature was reviewed for original research investigating in vitro, in vivo, and clinical applications of radiolabeled MIBG for neuroblastoma.
MIBG is actively transported into neuroblastoma cells by the norepinephrine transporter. Preclinical studies demonstrate substantial activity of radiolabeled MIBG in neuroblastoma models, with 131I-MIBG showing enhanced activity in larger tumors compared to 125I-MIBG. Clinical studies of 131I-MIBG in patients with relapsed or refractory neuroblastoma have identified myelosuppression as the main dose-limiting toxicity, necessitating stem cell reinfusion at higher doses. Most studies report a response rate of 30–40% with 131I-MIBG in this population. More recent studies have focused on the use of 131I-MIBG in combination with chemotherapy or myeloablative regimens.
131I-MIBG is an active agent for the treatment of patients with neuroblastoma. Future studies will need to define the optimal role of this targeted radiopharmaceutical in the therapy of this disease.
Metaiodobenzylguanidine; neuroblastoma; pediatric; radionuclide
TrkB acts as an oncogenic kinase in a subset of human neuroblastomas. Lestaurtinib, a multi-kinase inhibitor with potent activity against Trk kinases, has demonstrated activity in preclinical models of neuroblastoma.
Patients with refractory high-risk neuroblastoma received lestaurtinib twice daily for 5 days out of seven in 28-day cycles, starting at 70% of the adult recommended Phase 2 dose. Lestaurtinib dose was escalated using a 3 + 3 design. Pharmacokinetics and plasma phospho-TrkB inhibitory activity were evaluated in the first cycle.
Forty-seven subjects were enrolled, and 10 dose levels explored starting at 25 mg/M2/dose BID. Forty-six subjects were evaluable for response, and 42 subjects were fully evaluable for determination of dose escalation. Asymptomatic and reversible grade 3–4 transaminase elevation was dose limiting in 4 subjects. Reversible pancreatitis (grade 2) was observed in 3 subjects after prolonged treatment at higher dose levels. Other toxicities were mild and reversible. Pharmacokinetic analyses revealed rapid drug absorption, however inter-patient variability was large. Plasma inhibition of phospho-TrkB activity was observed 1 h post-dosing at 85 mg/M2 with uniform inhibition at 120 mg/M2. There were two partial responses and nine subjects had prolonged stable disease at dose levels ≥ 5, (median: 6 cycles). A biologically effective and recommended phase 2 dose of 120 mg/M2/dose BID was established.
Lestaurtinib was well tolerated in patients with refractory neuroblastoma, and a dose level sufficient to inhibit TrkB activity was established. Safety and signs of activity at the higher dose levels warrant further evaluation in neuroblastoma.
Neuroblastoma; Receptor tyrosine kinase; Targeted therapy; Lestaurtinib; Signal transduction
Annexin V staining has become a standard approach for identifying cells undergoing apoptosis in vitro and can be detected in plasma. We hypothesized that plasma annexin V levels might serve as a clinical marker of tumor burden and cell turnover in children and young adults with solid tumors.
Nine patients aged 4–22 with newly diagnosed solid tumors were enrolled. Plasma samples were obtained prior to and, in a subset of patients, after initiation of chemotherapy from which annexin V levels were determined by enzyme-linked immunosorbent assay (ELISA).
Three of nine patients had elevated plasma annexin V levels (> 10 ng/mL) at diagnosis and there was poor correlation to LDH levels, a commonly used marker of cell turnover (r = 0.66). Of the five patients with annexin V levels obtained after starting chemotherapy, only one showed an increase over the time period assessed.
Plasma annexin V does not appear to be a useful marker of tumor burden or early response to chemotherapy in children with solid tumors.
annexin V; apoptosis; laboratory correlates; pediatric cancers; Sarcoma/soft tissue malignancies