Off-label prescribing of immune checkpoint inhibitor therapy at a single pediatric cancer center

BACKGROUND

Immune checkpoint inhibitors (ICI) have improved outcomes in a variety of adult cancers and are prescribed with increasing frequency across oncology. However, patterns of off-label use of ICI in pediatrics remain unclear.

METHODS

This is a single-institution, retrospective cohort study evaluating off-label ICI use in pediatric and young adult patients with cancer treated at our institution from 2014 to 2022. Response was based on clinician assessment derived from clinical records. Immune-related adverse events (iRAEs) were classified according to CTCAE v5.0.

RESULTS

We identified 50 unique patients treated with off-label ICI (28 with solid tumors, 20 with central nervous system (CNS) tumors, 2 with hematologic malignancies). At time of ICI initiation, only five patients (10%) had localized disease, and all but one patient was treated in the relapsed/refractory setting. All patients were treated with the FDA-approved weight-based dosing recommendations. Overall, there was disease control in 21 patients (42%), with best response including one complete response (melanoma), two partial responses (high-grade glioma, CNS nongerminomatous germ cell tumor), and 18 patients with stable disease. Forty-four patients (88%) eventually experienced disease progression. Among 22 patients (44%) experiencing iRAEs, 10 (20%) had a grade ≥3 irAE, 12 (24%) required corticosteroids, and 14 (28%) required ICI discontinuation. irAE occurrence was associated with significantly improved progression-free survival (HR 0.35; 95% CI: 0.18 to 0.68; p = 0.002) and overall survival (HR 0.33; 95% CI: 0.17 to 0.66; p = 0.002).

CONCLUSIONS

At our institution, ICI was most commonly prescribed in the relapsed/refractory setting to patients with metastatic disease. The treatment was generally well-tolerated in the pediatric population. The overall response rate was low, and the majority of patients eventually experienced disease progression. A few patients, however, had durable treatment responses. Further studies are needed to identify which pediatric patients are most likely to benefit from ICI.

Reporting and impact of subsequent cycle toxicities in oncology phase I clinical trials

BACKGROUND/AIMS

As oncology treatments evolve, classic assumptions of toxicity associated with cytotoxic agents may be less relevant, requiring new design strategies for trials intended to inform dosing strategies for agents that may be administered beyond a set number of defined cycles. We describe the overall incidence of dose-limiting toxicities during and after cycle 1, frequency of reporting subsequent cycle toxicities, and the impact of post-cycle 1 dose-limiting toxicities on conclusions drawn from oncology phase 1 clinical trials.

METHODS

We conducted a systematic review of subsequent cycle toxicities in oncology phase I clinical trials published in the Journal of Clinical Oncology from 2000 to 2020. We used chi-square tests and multivariate logistic regression to describe predictors of reporting subsequent cycle toxicity data.

RESULTS

From 2000 to 2020, we identified 489 articles reporting on therapeutic phase 1 clinical trials. Of these, 421 (86%) reported data regarding cycle 1 dose-limiting toxicities and 170 (35%) reported data on cycle 1 dose modifications. Of the trials that reported cycle 1 dose-limiting toxicities, the median percentage of patients that experienced cycle 1 dose-limiting toxicities was 8.89%. Only 47 (9.6%) publications reported on post-cycle 1 dose-limiting toxicities and only 92 (19%) reported on dose modifications beyond cycle 1. Of the trials that reported post-cycle 1 dose-limiting toxicities, the median percentage of patients that experienced post-cycle 1 dose-limiting toxicities was 14.8%. Among the 371 studies with a recommended phase 2 dose, 89% did not report whether post-cycle 1 toxicities impacted the recommended phase 2 dose. More recent year of publication was independently associated with reduced odds of reporting subsequent cycle toxicity.

CONCLUSION

Reporting of subsequent cycle toxicity is uncommon in oncology phase I clinical trial publications and becoming less common over time. Guidelines for reporting of phase I oncology clinical trials should expand to include toxicity data beyond the first cycle.

Aurora Kinase A inhibition enhances DNA damage and tumor cell death with 131I-MIBG therapy in high-risk neuroblastoma

Background

Neuroblastoma is the most common extra-cranial pediatric solid tumor. 131I-metaiodobenzylguanidine (MIBG) is a targeted radiopharmaceutical highly specific for neuroblastoma tumors, providing potent radiotherapy to widely metastatic disease. Aurora kinase A (AURKA) plays a role in mitosis and stabilization of the MYCN protein in neuroblastoma. Here we explore whether AURKA inhibition potentiates a response to MIBG therapy.

Results

Using an in vivo model of high-risk neuroblastoma, we demonstrated a marked combinatorial effect of 131I-MIBG and alisertib on tumor growth. In MYCN amplified cell lines, the combination of radiation and an AURKA A inhibitor increased DNA damage and apoptosis and decreased MYCN protein levels.

Conclusion

The combination of AURKA inhibition with 131I-MIBG treatment is active in resistant neuroblastoma models and is a promising clinical approach in high-risk neuroblastoma.

Norepinephrine transporter and vesicular monoamine transporter 2 tumor expression as a predictor of response to 131 I-MIBG in patients with relapsed/refractory neuroblastoma

BACKGROUND

Prior studies suggest that norepinephrine transporter (NET) and vesicular monoamine transporter 2 (VMAT2) mediate meta-iodobenzylguanidine (MIBG) uptake and retention in neuroblastoma tumors. We evaluated the relationship between NET and VMAT2 tumor expression and clinical response to 131 I-MIBG therapy in patients with neuroblastoma.

METHODS

Immunohistochemistry (IHC) was used to evaluate NET and VMAT2 protein expression levels on archival tumor samples (obtained at diagnosis or relapse) from patients with relapsed or refractory neuroblastoma treated with 131 I-MIBG. A composite protein expression H-score was determined by multiplying a semi-quantitative intensity value (0-3+) by the percentage of tumor cells expressing the protein.

RESULTS

Tumor samples and clinical data were available for 106 patients, of whom 28.3% had partial response (PR) or higher. NET H-score was not significantly associated with response (≥PR), though the percentage of tumor cells expressing NET was lower among responders (median 80% for ≥PR vs. 90% for

CONCLUSIONS

Markers of lower NET and VMAT2 protein expression are associated with higher likelihood of response to 131 I-MIBG therapy in patients with relapsed/refractory neuroblastoma. Increased VMAT2 protein expression is associated with a more differentiated disease phenotype.

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Key Words

• 131I-MIBG
• biomarker
• neuroblastoma
• norepinephrine transporter
• vesicular monoamine transporter 2

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MESH Headings

• Humans
• 3-Iodobenzylguanidine/therapeutic use
• Norepinephrine Plasma Membrane Transport Proteins/metabolism
• Vesicular Monoamine Transport Proteins/metabolism
• Radiopharmaceuticals
• N-Myc Proto-Oncogene Protein
• Neoplasm Recurrence, Local/drug therapy
• Neuroblastoma/drug therapy
• Chronic Disease

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Grants

• R01 CA172067 NCI NIH HHS
• R35 CA220500 NCI NIH HHS
• R01 CA172067 NIH HHS
• R35 CA220500 NIH HHS

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Affiliation(s)

Vandana Batra Children’s Hospital of Philadelphia and Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA
Ajami Gikandi Harvard Medical School, Boston, MA
Bruce Pawel Department of Pathology, Children’s Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA
Daniel Martinez Children’s Hospital of Philadelphia and Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA
M. Meaghan Granger Department of Pediatrics, Cook Children’s Hospital, Fort Worth, TX
Araz Marachelian Department of Pediatrics, Children’s Hospital Los Angeles and USC Keck School of Medicine, Los Angeles, CA
Julie R. Park Department of Pediatrics, Seattle Children’s Hospital and University of Washington School of Medicine, Seattle, WA
John M. Maris Children’s Hospital of Philadelphia and Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA
Kieuhoa T. Vo Department of Pediatrics, UCSF Benioff Children’s Hospital and UCSF School of Medicine, San Francisco, CA
Katherine K. Matthay Department of Pediatrics, UCSF Benioff Children’s Hospital and UCSF School of Medicine, San Francisco, CA
Steven G. DuBois Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, Harvard Medical School, Boston, MA

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Initial Chemotherapy for Locally Advanced and Metastatic NUT Carcinoma

INTRODUCTION

NUT carcinoma (NC) is an underdiagnosed and aggressive poorly differentiated or squamous cell cancer. A subset of NC is sensitive to chemotherapy, but the optimal regimen is unknown. Experts have recommended platinum- and ifosfamide-based therapy based on case reports.

METHODS

Patients with pathologically confirmed NC with known survival outcomes after chemotherapy and consented to participate in a worldwide registry were studied. Results were summarized using descriptive methods.

RESULTS

The study included 118 patients with NC. Median age was 34 (range: 1-82) years, 39% were women, and 61% harbored a BRD4::NUTM1 fusion. Patients received platinum (74%) or ifosfamide (26%, including regimens with both, 13%). Of 62 patients with nonmetastatic disease, 40% had a thoracic primary. Compared with platinum-based chemotherapy, patients who received ifosfamide-based chemotherapy had nominally higher progression-free survival (12 mo: 59% [95% CI: 32-87] versus 37% [95% CI: 22-52], hazard ratio = 0.68 [0.32, 1.42], p = 0.3) but not overall survival (OS). Among the 56 patients with metastatic disease, 80% had a thoracic primary. Ifosfamide had an objective response rate (ORR) of 75% (six of eight) and platinum had an ORR of 31% (11 of 36). Nevertheless, there was no difference in progression-free survival or OS. The 3-year OS of the entire cohort was 19% (95% CI: 10%-28%). Of the 11 patients alive greater than 3 years, all presented with nonmetastatic and operable or resectable disease.

CONCLUSION

There is a numerically higher ORR for ifosfamide-based therapy compared with platinum-based therapy, with limited durability. OS at 3 years is only 19%, and development of effective therapies is an urgent unmet need for this patient population.

Phase 1 study of cabozantinib in combination with topotecan-cyclophosphamide for patients with relapsed Ewing sarcoma or osteosarcoma

PURPOSE

Phase 1 study assessing the safety and toxicity of cabozantinib in combination with topotecan and cyclophosphamide for relapsed osteosarcoma and Ewing sarcoma.

METHODS

Oral cabozantinib (25 mg/m2 ) was administered daily for 21 (dose level 1) or 14 (dose level -1B) days. Topotecan (0.75 mg/m2 ) and cyclophosphamide (250 mg/m2 ) were administered intravenously (IV) on days 1-5. A modified 3+3 design based upon first cycle dose-limiting toxicities (DLT) was used for dose escalation.

RESULTS

Twelve patients with a median age of 15 (12.9-33.2) years were enrolled (seven with Ewing sarcoma; five with osteosarcoma); all were evaluable for toxicity. At dose level 1, three of six patients developed first cycle DLT: grade 3 epistaxis, grade 3 transaminitis, and prolonged grade 2 thrombocytopenia. Six patients were enrolled on dose level -1B (interrupted cabozantinib, given days 8-21), with one first cycle DLT (grade 3 pneumothorax) observed. Of the 10 response evaluable patients, one had partial response (Ewing sarcoma), seven had stable disease, and two had progressive disease.

CONCLUSIONS

The recommended phase 2 doses and schedules for this combination are topotecan 0.75 mg/m2 IV days 1-5, cyclophosphamide 250 mg/m2 IV days 1-5, and cabozantinib 25 mg/m2 days 8-21. Non-concomitant administration of cabozantinib with cytotoxic therapy in this population has acceptable toxicity, while allowing for potential disease control.

Evaluation of prevalence and outcomes of serial tyrosine kinase inhibitor use in pediatric patients with advanced solid tumors

PURPOSE

Multitargeted tyrosine kinase inhibitors (mTKIs) are increasingly utilized in the treatment of pediatric sarcomas and other solid tumors. It is unknown whether serial treatment with multiple TKIs provides a benefit and which patients are most likely to benefit from mTKI rechallenge.

METHODS

We performed a retrospective cohort study of pediatric cancer patients who received serial mTKI therapy off-study between 2007 and 2020 as either monotherapy or combination therapy. We report patient characteristics, clinical outcomes, dosing patterns, and treatment-associated toxicity.

RESULTS

The study cohort included 25 patients. The overall prevalence of serial mTKI therapy among all patients treated for sarcoma at our institution was 3.7%, and the response rate to second mTKI was 9%. Median 6-month progression-free survival (PFS) and overall survival (OS) from start of second mTKI were 42.1% (95% CI: 20.4%-62.5%) and 79.1% (95% CI: 57.0%-90.8%), respectively. Patients who had received 4 months or more (n = 11) of therapy with first mTKI had significantly longer PFS versus those who received less than 4 months (n = 11; p = .001). Thirty-three percent of patients discontinued second mTKI due to toxicity. Six (40%) of 15 patients who discontinued the first mTKI due to progression had either a partial response or stable disease on the second mTKI.

CONCLUSIONS

We observed a low response rate to mTKI rechallenge. However, we identified patients who had been treated with first mTKI for  ≥4 months as more likely to have prolonged stable disease with second mTKI. Several patients had a response or stable disease on the second mTKI despite having progressed on the first mTKI. Though toxicity was common, only a minority of patients discontinued the second mTKI due to toxicity.

Long-Term Outcomes in Patients With Localized Ewing Sarcoma Treated With Interval-Compressed Chemotherapy on Children's Oncology Group Study AEWS0031

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned coprimary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Long-term outcomes from Children's Oncology Group study AEWS0031 were assessed to determine whether the survival advantage of interval-compressed chemotherapy (ICC) was maintained over 10 years in patients with localized Ewing sarcoma (ES). AEWS0031 enrolled 568 eligible patients. Patients were randomly assigned to receive vincristine-doxorubicin-cyclophosphamide and ifosfamide-etoposide alternating once every 3 weeks (standard timing chemotherapy [STC]) versus once every 2 weeks (ICC). For this updated report, one patient was excluded because of uncertainty of original diagnosis. The 10-year event-free survival (EFS) was 70% with ICC compared with 61% with STC (P = .03), and 10-year overall survival (OS) was 76% with ICC compared with 69% with STC (P = .04). There was no difference in the 10-year cumulative incidence of second malignant neoplasms (SMNs; PC [see Data Supplement, online only] = .5). A test for interaction demonstrated that ICC provided greater risk reduction for patients with tumor volume ≥200 mL than for patients with tumors <200 mL, but no evidence for a significant interaction in other subgroups defined by age, primary site, and histologic response. With longer-term follow-up, ICC for localized ES is associated with superior EFS and OS without an increased risk for SMN compared with STC. ICC is associated with improved outcomes even in adverse-risk patient groups.

Children's Oncology Group's 2023 blueprint for research: Neuroblastoma

Neuroblastoma is the most common extra-cranial solid tumor in children and is known for its clinical heterogeneity. A greater understanding of the biology of this disease has led to both improved risk stratification and new approaches to therapy. Outcomes for children with low and intermediate risk disease are excellent overall, and efforts to decrease therapy for such patients have been largely successful. Although survival has improved over time for patients with high-risk disease and treatments evaluated in the relapse setting are now being moved into earlier phases of treatment, much work remains to improve survival and decrease therapy-related toxicities. Studies of highly annotated biobanked samples continue to lead to important insights regarding neuroblastoma biology. Such studies, along with correlative biology studies incorporated into therapeutic trials, are expected to continue to provide insights that lead to new and more effective therapies. A focus on translational science is accompanied by an emphasis on new agent development, optimized risk stratification, and international collaboration to address questions relevant to molecularly defined subsets of patients. In addition, the COG Neuroblastoma Committee is committed to addressing the patient/family experience, mitigating late effects of therapy, and studying social determinants of health in patients with neuroblastoma.

Children's Oncology Group's 2023 blueprint for research: Bone tumors

The Children's Oncology Group (COG) Bone Tumor Committee is responsible for clinical trials and biological research on localized, metastatic, and recurrent osteosarcoma and Ewing sarcoma (EWS). Results of clinical trials in localized disease completed and published in the past 10 years have led to international standard-of-care chemotherapy for osteosarcoma and EWS. A recent focus on identifying disease subgroups has led to the identification of biological features associated with poor outcomes including the presence of circulating tumor DNA (ctDNA) at diagnosis, and specific genomic alterations-MYC amplification for osteosarcoma and STAG2 and TP53 mutation for EWS. Studies validating these potential biomarkers are under way. Clinical trials evaluating the addition of multitargeted kinase inhibitors, which are active in relapsed bone sarcomas, to standard chemotherapy are under way in osteosarcoma and planned in EWS. In addition, the Committee has data analyses and a clinical trial under way to evaluate approaches to local management of the primary tumor and metastatic sites. Given the rarity of bone sarcomas, we have prioritized international interactions and are in the process of forming an international data-sharing consortium to facilitate refinement of risk stratification and study of rare disease subtypes.

Clinical development of new drugs for adults and children with cancer, 2010-2020

BACKGROUND

Many new molecular entities enter clinical development to evaluate potential therapeutic benefits for oncology patients. We characterized adult and pediatric development of the set of new molecular entities that started clinical testing in 2010-2015 worldwide.

METHODS

We extracted data from AdisInsight, an extensive database of global pharmaceutical development, and the FDA.gov website. We followed the cohort of new molecular entities initiating first-in-human phase I clinical trials in 2010-2015 to the end of 2020. For each new molecular entity, we determined whether it was granted US Food and Drug Administration (FDA) approval, studied in a trial open to pediatric enrollment, or stalled during development. We characterized the cumulative incidence of these endpoints using statistical methods for censored data.

RESULTS

The 572 new molecular entities starting first-in-human studies in 2010-2015 were studied in 6142 trials by the end of 2020. Most new molecular entities were small molecules (n = 316, 55.2%), antibodies (n = 148, 25.9%), or antibody-drug conjugates (n = 44, 7.7%). After a mean follow-up of 8.0 years, 173 new molecular entities did not advance beyond first-in-human trials, and 39 were approved by the FDA. New molecular entities had a 10.4% estimated probability (95% confidence interval = 6.6% to 14.1%) of being approved by the FDA within 10 years of first-in-human trials. After a median of 4.6 years since start of first-in-human trials, 67 (11.7%) new molecular entities were tested in trials open to pediatric patients, and 5 (0.9%) were approved for pediatric indications.

CONCLUSIONS

More efficient clinical development strategies are needed to evaluate new cancer therapies, especially for children, and incorporate approaches to ensure knowledge gain from investigational products that stall in development.

Phase 2 trial of palbociclib and ganitumab in patients with relapsed Ewing sarcoma

BACKGROUND

Ewing sarcoma (EWS) is an aggressive sarcoma with few treatment options for patients with relapsed disease. Cyclin-dependent kinase 4 (CDK4) is a genomic vulnerability in EWS that is synergistic with IGF-1R inhibition in preclinical studies. We present the results of a phase 2 study combining palbociclib (CDK4/6 inhibitor) with ganitumab (IGF-1R monoclonal antibody) for patients with relapsed EWS.

PATIENTS AND METHODS

This open-label, non-randomized, phase 2 trial enrolled patients ≥12 years with relapsed EWS. All patients had molecular confirmation of EWS and RECIST measurable disease. Patients initially received palbociclib 125 mg orally on Days 1-21 and ganitumab 18 mg/kg intravenously on Days 1 and 15 of a 28-day cycle. The primary endpoints were objective response (complete or partial) per RECIST and toxicity by CTCAE. An exact one-stage design required ≥4 responders out of 15 to evaluate an alternative hypothesis of 40% response rate against a null of 10%. The study was closed following enrollment of the 10th patient due to discontinuation of ganitumab supply.

RESULTS

Ten evaluable patients enrolled [median age 25.7 years (range 12.3-40.1)]. The median duration of therapy was 2.5 months (range 0.9-10.8). There were no complete or partial responders. Three of 10 patients had stable disease for >4 cycles and 2 had stable disease at completion of planned therapy or study closure. Six-month progression-free survival was 30% (95% CI 1.6%-58.4%). Two patients had cycle 1 hematologic dose-limiting toxicities (DLTs) triggering palbociclib dose reduction to 100 mg daily for 21 days. Two subsequent patients had cycle 1 hematologic DLTs at the reduced dose. Eighty percent of patients had grade 3/4 AEs, including neutropenia (n = 8), white blood cell decreased (n = 7), and thrombocytopenia (n = 5). Serum total IGF-1 significantly increased (p = 0.013) and ctDNA decreased during the first cycle.

CONCLUSIONS

This combination lacks adequate therapeutic activity for further study, though a subset of patients had prolonged stable disease.

Combination Early-Phase Trials of Anticancer Agents in Children and Adolescents

PURPOSE

There is an increasing need to evaluate innovative drugs for childhood cancer using combination strategies. Strong biological rationale and clinical experience suggest that multiple agents will be more efficacious than monotherapy for most diseases and may overcome resistance mechanisms and increase synergy. The process to evaluate these combination trials needs to maximize efficiency and should be agreed by all stakeholders.

METHODS

After a review of existing combination trial methodologies, regulatory requirements, and current results, a consensus among stakeholders was achieved.

RESULTS

Combinations of anticancer therapies should be developed on the basis of mechanism of action and robust preclinical evaluation, and may include data from adult clinical trials. The general principle for combination early-phase studies is that, when possible, clinical trials should be dose- and schedule-confirmatory rather than dose-exploratory, and every effort should be made to optimize doses early. Efficient early-phase combination trials should be seamless, including dose confirmation and randomized expansion. Dose evaluation designs for combinations depend on the extent of previous knowledge. If not previously evaluated, limited evaluation of monotherapy should be included in the same clinical trial as the combination. Randomized evaluation of a new agent plus standard therapy versus standard therapy is the most effective approach to isolate the effect and toxicity of the novel agent. Platform trials may be valuable in the evaluation of combination studies. Patient advocates and regulators should be engaged with investigators early in a proposed clinical development pathway and trial design must consider regulatory requirements.

CONCLUSION

An optimized, agreed approach to the design and evaluation of early-phase pediatric combination trials will accelerate drug development and benefit all stakeholders, most importantly children and adolescents with cancer.

A single-institution pediatric and young adult interventional oncology collaborative: Novel therapeutic options for relapsed/refractory solid tumors

BACKGROUND

Pediatric interventional oncology (PIO) is a growing field intended to provide additional or alternative treatment options for pediatric patients with benign or malignant tumors. Large series of patients treated uniformly and subjected to rigorous endpoints for efficacy are not available.

METHODS

We designed a collaborative initiative to capture data from pediatric patients with benign and malignant tumors who underwent a therapeutic interventional radiology procedure. Modified Response Evaluation Criteria in Solid Tumors (mRECIST) was utilized as a measure of radiologic response and data were collected regarding improvement in pain and functional endpoints. Cumulative incidence of progressive disease was calculated using both the treated site and the patient as the analytic unit.

FINDINGS

Forty patients, 16 with malignant tumors and 24 with benign tumors, underwent a total of 88 procedures. Cryo- and radiofrequency ablation were the most frequently utilized techniques for both cohorts of patients. A complete or partial response, or prolonged disease stability, were achieved in approximately 40% of patients with malignant tumors and 60% of patients with benign tumors. No patients had progressive disease as their best response. Resolution of pain and improved mobility with return-to-baseline activity were demonstrated across patients from both cohorts. Only minor complications were experienced.

INTERPRETATION

Interventional radiology-guided interventions can serve as an alternative or complementary approach to the treatment of benign and malignant tumors in pediatric patients. Prospective, multi-institutional trials are required to adequately study utility, treatment endpoints, and durability of response.

Circulating Tumor DNA Is Prognostic in Intermediate-Risk Rhabdomyosarcoma: A Report From the Children's Oncology Group

PURPOSE

Novel biomarkers are needed to differentiate outcomes in intermediate-risk rhabdomyosarcoma (IR RMS). We sought to evaluate strategies for identifying circulating tumor DNA (ctDNA) in IR RMS and to determine whether ctDNA detection before therapy is associated with outcome.

PATIENTS AND METHODS

Pretreatment serum and tumor samples were available from 124 patients with newly diagnosed IR RMS from the Children's Oncology Group biorepository, including 75 patients with fusion-negative rhabdomyosarcoma (FN-RMS) and 49 with fusion-positive rhabdomyosarcoma (FP-RMS) disease. We used ultralow passage whole-genome sequencing to detect copy number alterations and a new custom sequencing assay, Rhabdo-Seq, to detect rearrangements and single-nucleotide variants.

RESULTS

We found that ultralow passage whole-genome sequencing was a method applicable to ctDNA detection in all patients with FN-RMS and that ctDNA was detectable in 13 of 75 serum samples (17%). However, the use of Rhabdo-Seq in FN-RMS samples also identified single-nucleotide variants, such as MYOD1L122R, previously associated with prognosis. Identification of pathognomonic translocations between PAX3 or PAX7 and FOXO1 by Rhabdo-Seq was the best method for measuring ctDNA in FP-RMS and detected ctDNA in 27 of 49 cases (55%). Patients with FN-RMS with detectable ctDNA at diagnosis had significantly worse outcomes than patients without detectable ctDNA (event-free survival, 33.3% v 68.9%; P = .0028; overall survival, 33.3% v 83.2%; P < .0001) as did patients with FP-RMS (event-free survival, 37% v 70%; P = .045; overall survival, 39.2% v 75%; P = .023). In multivariable analysis, ctDNA was independently associated with worse prognosis in FN-RMS but not in the smaller FP-RMS cohort.

CONCLUSION

Our study demonstrates that baseline ctDNA detection is feasible and is prognostic in IR RMS.

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

BACKGROUND

Understanding the landscape of clinical trials for patients with neuroblastoma may inform efforts to improve drug development.

PROCEDURE

We evaluated therapeutic trials for patients with neuroblastoma from 2011 to 2020 in our search using clinical trial information from ClinicalTrials.gov, Clinicaltrialregister.eu, PubMed, and American Society of Clinical Oncology (ASCO) annual meeting collection. Trends in trials and treatments over time were evaluated qualitatively.

RESULTS

A total of 192 trials met inclusion criteria. A median of 20.5 trials were started per year, which was stable over time. There were 87 (45%) phase 1, 100 (51%) phase 2, and only five (2.6%) phase 3 trials. The median time to completion was 4.9 years for phase 1 and 2 trials (no phase 3 trials reported as completed during the study period). In all, 34% of trials were international, while 20% of trials were intercontinental. Eighty-nine percent of nonmyeloablative trials included at least one novel agent. 48% of these trials studied combination therapies, and 86% of these combinations included conventional chemotherapy. Among 157 trials that included a targeted agent, 78 targets were identified, with GD2 being the primary target under investigation in 16.7% of these trials. Only eight trials were included in regulatory decisions, which led to European Medicines Agency (EMA) or Food and Drug Administration (FDA) approval for neuroblastoma.

CONCLUSIONS

The large number of trials initiated per year, the range of targets, and the rate of intercontinental collaboration are encouraging. The paucity of late-stage trials, the prolonged trial duration, and relative lack of combination studies are major causes of concern. This work will inform future drug development for neuroblastoma.

Randomized Phase III Trial of Ganitumab With Interval-Compressed Chemotherapy for Patients With Newly Diagnosed Metastatic Ewing Sarcoma: A Report From the Children's Oncology Group

PURPOSE

Monoclonal antibodies directed against insulin-like growth factor-1 receptor (IGF-1R) have shown activity in patients with relapsed Ewing sarcoma. The primary objective of Children's Oncology Group trial AEWS1221 was to determine if the addition of the IGF-1R monoclonal antibody ganitumab to interval-compressed chemotherapy improves event-free survival (EFS) in patients with newly diagnosed metastatic Ewing sarcoma.

METHODS

Patients were randomly assigned 1:1 at enrollment to standard arm (interval-compressed vincristine/doxorubicin/cyclophosphamide alternating once every 2 weeks with ifosfamide/etoposide = VDC/IE) or to experimental arm (VDC/IE with ganitumab at cycle starts and as monotherapy once every 3 weeks for 6 months after conventional therapy). A planned sample size of 300 patients was projected to provide 81% power to detect an EFS hazard ratio of 0.67 or smaller for the experimental arm compared with the standard arm with a one-sided α of .025.

RESULTS

Two hundred ninety-eight eligible patients enrolled (148 in standard arm; 150 in experimental arm). The 3-year EFS estimates were 37.4% (95% CI, 29.3 to 45.5) for the standard arm and 39.1% (95% CI, 31.3 to 46.7) for the experimental arm (stratified EFS-event hazard ratio for experimental arm 1.00; 95% CI, 0.76 to 1.33; 1-sided, P = .50). The 3-year overall survival estimates were 59.5% (95% CI, 50.8 to 67.3) for the standard arm and 56.7% (95% CI, 48.3 to 64.2) for the experimental arm. More cases of pneumonitis after radiation involving thoracic fields and nominally higher rates of febrile neutropenia and ALT elevation were reported on the experimental arm.

CONCLUSION

Ganitumab added to interval-compressed chemotherapy did not significantly reduce the risk of EFS event in patients with newly diagnosed metastatic Ewing sarcoma, with outcomes similar to prior trials without IGF-1R inhibition or interval compression. The addition of ganitumab may be associated with increased toxicity.

Ewing Sarcoma Drug Therapy: Current Standard of Care and Emerging Agents

Ewing sarcoma is a translocation-associated sarcoma mainly impacting adolescents and young adults. The classic translocation (EWSR1::FLI1) leads to a fusion oncoprotein that functions as an aberrant transcription factor. As such, the oncogenic driver of this disease has been difficult to target pharmacologically and, therefore, the systemic therapies used to treat patients with Ewing sarcoma have typically been non-selective cytotoxic chemotherapy agents. The current review highlights recent clinical trials from the last decade that provide the evidence base for contemporary drug therapy for patients with Ewing sarcoma, while also highlighting novel therapies under active clinical investigation in this disease. We review recent trials that have led to the establishment of interval-compressed chemotherapy as an international standard for patients with newly diagnosed localized disease. We further highlight recent trials that have shown a lack of demonstrable benefit from high-dose chemotherapy or IGF-1R inhibition for patients with newly diagnosed metastatic disease. Finally, we provide an overview of chemotherapy regimens and targeted therapies used in the management of patients with recurrent Ewing sarcoma.

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.

A global collaboRAtive study of CIC-rearranged, BCOR::CCNB3-rearranged and other ultra-rare unclassified undifferentiated small round cell sarcomas (GRACefUl)

BACKGROUND

Undifferentiated small round cell sarcomas (URCSs) represent a diagnostic challenge, and their optimal treatment is unknown. We aimed to define the clinical characteristics, treatment, and outcome of URCS patients.

METHODS

URCS patients treated from 1983 to 2019 at 21 worldwide sarcoma reference centres were retrospectively identified. Based on molecular assessment, cases were classified as follows: (1) CIC-rearranged round cell sarcomas, (2) BCOR::CCNB3-rearranged round cell sarcomas, (3) unclassified URCSs. Treatment, prognostic factors and outcome were reviewed.

RESULTS

In total, 148 patients were identified [88/148 (60%) CIC-rearranged sarcoma (median age 32 years, range 7-78), 33/148 (22%) BCOR::CCNB3-rearranged (median age 17 years, range 5-91), and 27/148 (18%) unclassified URCSs (median age 37 years, range 4-70)]. One hundred-one (68.2%) cases presented with localised disease; 47 (31.8%) had metastases at diagnosis. Male prevalence, younger age, bone primary site, and a low rate of synchronous metastases were observed in BCOR::CCNB3-rearranged cases. Local treatment was surgery in 67/148 (45%) patients, and surgery + radiotherapy in 52/148 (35%). Chemotherapy was given to 122/148 (82%) patients. At a 42.7-month median follow-up, the 3-year overall survival (OS) was 92.2% (95% CI 71.5-98.0) in BCOR::CCNB3 patients, 39.6% (95% CI 27.7-51.3) in CIC-rearranged sarcomas, and 78.7% in unclassified URCSs (95% CI 56.1-90.6; p < 0.0001).

CONCLUSIONS

This study is the largest conducted in URCS and confirms major differences in outcomes between URCS subtypes. A full molecular assessment should be undertaken when a diagnosis of URCS is suspected. Prospective studies are needed to better define the optimal treatment strategy in each URCS subtype.

Early Termination of Oncology Clinical Trials in the United States

PURPOSE

The aim of this study was to evaluate the rate of early trial discontinuation of oncology trials and reasons for early termination, to assess potential trends in rates of oncology trial termination, and to perform a comprehensive analysis of predictors of early termination. This study intends to inform efforts in improving efficiency of the oncology clinical trial enterprise.

METHODS

We conducted a cross-sectional study of interventional cancer clinical trials registered in ClinicalTrials.gov database from September 27, 2007 to June 30, 2015, with at least one site listed in the United States. We evaluated predictors of early trial termination using Fisher exact or χ² tests and logistic regression.

RESULTS

Of 8687 trials, 22.74% (n = 1975) were terminated trials. Rates of early trial termination appeared stable over the study. Statistically significant univariate predictors of early termination for any reason include cancer category, phase, funding source, location, and age. In multivariable analysis, trials spanning multiple cancer categories and international trials were less likely to terminate early whereas phase 2 trials and trials funded by academia/foundation were more likely to terminate early. The most common reason for early termination was "Other, Multiple Reasons, or Unknown" (36.9%), followed by accrual issues (34.5%). In multivariate analysis among all terminated trials, supportive care trials, phase 2 trials, and non-industry funded trials had significantly higher odds of trial discontinuation specifically due to poor accrual.

CONCLUSION

In this national sample of cancer clinical trials, early trial discontinuation was common. Many factors influenced early trial termination with poor accrual being a common reason. Specific trial features are associated with differential likelihood of early trial termination for any reason and for early trial termination due to poor accrual.

Analysis of Local Control Outcomes and Clinical Prognostic Factors in Localized Pelvic Ewing Sarcoma Patients Treated With Radiation Therapy: A Report From the Children's Oncology Group

PURPOSE

To identify potential clinical prognostic factors associated with a higher risk of local recurrence in patients with localized pelvic Ewing sarcoma treated with radiation therapy.

METHODS AND MATERIALS

Data for 101 patients treated with definitive radiation therapy (RT) or both surgery and radiation (S + RT) to primary pelvic tumors on INT-0091, INT-0154, and AEWS0031 were analyzed. Imaging data for patients who did not receive radiation were not available for central review; therefore, patients with surgery alone were not included. Cumulative incidence rates for local failure at 5 years from time of local control were calculated accounting for competing risks.

RESULTS

The most common pelvic subsite was sacrum (44.6%). RT was used in 68% of patients and S + RT in 32%. The local failure rate was 25.0% for RT and 6.3% for S + RT (P = .046). There was no statistically significant difference in local control modality by tumor characteristics. Tumors originating in the ischiopubic-acetabulum region were associated with the highest local failure incidence, 37.5% (P = .02, vs sacrum and iliac/buttock tumors), particularly those treated with RT (50.0%, P = .06). A higher incidence of local failure was seen with each additional 100 mL of tumor at diagnosis (P = .04). Multivariable analysis demonstrated RT alone (hazard ratio [HR], 5.1; P = .04), tumor subsite (particularly ischiopubic-acetabulum tumors; HR 4.6; P = .02), and increasing volume per 100 mL (HR, 1.2; P = .01) were associated with a higher incidence of local recurrence.

CONCLUSIONS

Combination surgery and RT is associated with improved local control in patients with pelvic Ewing sarcoma compared with definitive RT. Tumors involving the ischiopubic-acetabulum region and increasing tumor volume at diagnosis are associated with inferior local control. Tumor characteristics did not correlate with choice of local therapy modality suggesting an opportunity to develop best local therapy practices guidelines for future studies based on tumor features.

Clinical and biological features prognostic of survival after relapse or progression of INRGSS stage MS pattern neuroblastoma: A report from the International Neuroblastoma Risk Group (INRG) project

BACKGROUND

Outcomes for patients with INRGSS metastatic special (MS) metastatic pattern neuroblastoma at initial diagnosis are well described. Prognosis after an initial event (relapse, progression, secondary malignancy) is unclear.

METHODS

We investigated characteristics of MS pattern neuroblastoma patients in the International Neuroblastoma Risk Group database who subsequently experienced an event. Post-event overall survival (OS) ± standard error was calculated overall and by diagnosis era: before 2000 versus 2001 or after. Cox models were used to identify factors prognostic of post-event OS.

RESULTS

Among 209 patients with an event, 88% were less than 365 days old at diagnosis; tumors were MYCN amplified in 24% and diploid in 33%. The median (range) time from diagnosis to first event was 8.16 months (7 days to 11.24 years). Of 96 patients with known relapse/progression pattern, 75% were metastatic or primary plus metastatic. Five-year post-event OS was 53% ± 3.6% and was higher for 2001 and afterwards (62% ± 5.0%) compared to before 2001 (44% ± 4.9%; p = .0046). In patients diagnosed in 2001 and after, older age, Hispanic ethnicity, MYCN amplification, 1p LOH, diploidy, high Mitotic Karyorrhexis Index, high lactate dehydrogenase (LDH), unfavorable histology, and longer time to first event were prognostic of worse post-event OS. Independent adverse prognostic factors on multivariable testing were non-White race, MYCN amplification, and diploidy.

SUMMARY

Patients diagnosed in and after 2001 have substantially better post-event OS compared to before 2001. In those diagnosed in and after 2001, most well-accepted prognostic factors for OS at diagnosis are also prognostic of post-event OS. Future studies may evaluate strategies to improve outcomes in this rare population.

Rare FGFR Oncogenic Alterations in Sequenced Pediatric Solid and Brain Tumors Suggest FGFR Is a Relevant Molecular Target in Childhood Cancer

PURPOSE

Multiple FGFR inhibitors are currently in clinical trials enrolling adults with different solid tumors, while very few enroll pediatric patients. We determined the types and frequency of FGFR alterations (FGFR1-4) in pediatric cancers to inform future clinical trial design.

METHODS

Tumors with FGFR alterations were identified from two large cohorts of pediatric solid tumors subjected to targeted DNA sequencing: The Dana-Farber/Boston Children's Profile Study (n = 888) and the multi-institution GAIN/iCAT2 (Genomic Assessment Improves Novel Therapy) Study (n = 571). Data from the combined patient population of 1,395 cases (64 patients were enrolled in both studies) were reviewed and cases in which an FGFR alteration was identified by OncoPanel sequencing were further assessed.

RESULTS

We identified 41 patients with tumors harboring an oncogenic FGFR alteration. Median age at diagnosis was 8 years (range, 6 months-26 years). Diagnoses included 11 rhabdomyosarcomas, nine low-grade gliomas, and 17 other tumor types. Alterations included gain-of-function sequence variants (n = 19), amplifications (n = 10), oncogenic fusions (FGFR3::TACC3 [n = 3], FGFR1::TACC1 [n = 1], FGFR1::EBF2 [n = 1], FGFR1::CLIP2 [n = 1], and FGFR2::CTNNA3 [n = 1]), pathogenic-leaning variants of uncertain significance (n = 4), and amplification in combination with a pathogenic-leaning variant of uncertain significance (n = 1). Two novel FGFR1 fusions in two different patients were identified in this cohort, one of whom showed a response to an FGFR inhibitor.

CONCLUSION

In summary, activating FGFR alterations were found in approximately 3% (41/1,395) of pediatric solid tumors, identifying a population of children with cancer who may be eligible and good candidates for trials evaluating FGFR-targeted therapy. Importantly, the genomic and clinical data from this study can help inform drug development in accordance with the Research to Accelerate Cures and Equity for Children Act.

Pattern and predictors of sites of relapse in neuroblastoma: A report from the International Neuroblastoma Risk Group (INRG) project

PURPOSE

We sought to analyze biologic, clinical, and prognostic differences according to pattern of failure at the time of first relapse in neuroblastoma.

PATIENTS AND METHODS

Children <21 years diagnosed with neuroblastoma between 1989 and 2017 with known site of first relapse (isolated local vs. distant only vs. combined local and distant sites) were identified from the International Neuroblastoma Risk Group (INRG) database. Data were compared between sites of relapse according to clinical features, biologic features, initial treatment, time to first relapse, and overall survival (OS) from time of first relapse.

RESULTS

Pattern of first relapse among 1833 children was 19% isolated local; 65% distant only; and 16% combined sites. All evaluated clinical and biologic variables with exception of tumor diagnosis differed statistically by relapse pattern, with patients with isolated local failure having more favorable prognostic features. Patients with stage 3 disease were more likely to have isolated local failure compared to all other stages (49% vs. 16%; p < .001). OS significantly differed by relapse pattern (5-year OS ± SE): isolated local: 64% ± 3%; distant only: 23% ± 2%; and combined: 26% ± 4% (p < .001). After controlling for age, stage, and MYCN status, patients with isolated local failure (adjusted hazard ratio [HR] = 0.46; 95% confidence interval [CI]: 0.33-0.62; p < .001) and distant-only failure (adjusted HR = 0.57; 95% CI: 0.45-0.71; p < .001) remained at decreased risk for death as compared to patients with combined failure.

CONCLUSION

Patients with distant-only and combined failures have a higher proportion of unfavorable clinical and biological features, and a lower survival than those with isolated local relapse.

Phase 2 study of anti-disialoganglioside antibody, dinutuximab, in combination with GM-CSF in patients with recurrent osteosarcoma: A report from the Children's Oncology Group

PURPOSE

Novel effective therapies are urgently needed in recurrent osteosarcoma. GD2 is expressed in human osteosarcoma tumours and cell lines. This study evaluated the disease control rate (DCR) in patients with recurrent osteosarcoma treated with the anti-GD2 antibody dinutuximab plus cytokine therapy as compared to historical outcomes.

METHODS

AOST1421 was a single-arm Phase 2 study for patients with recurrent pulmonary osteosarcoma in complete surgical remission. Patients received up to five cycles of dinutuximab (70 mg/m2/cycle) with granulocyte-macrophage colony-stimulating factor (GM-CSF). Two different dinutuximab infusion schedules were studied: 35 mg/m2/day over 20 h (2 days) and 17.5 mg/m2/day over 10 h (4 days). Primary end point was DCR, defined as a proportion of patients event free at 12 months from enrolment. The historical benchmark was 12-month DCR of 20% (95% CI 10-34%). Dinutuximab would be considered effective if ≥ 16/39 patients remained event free. Secondary objectives included toxicity evaluation and pharmacokinetics.

RESULTS

Thirty-nine eligible patients were included in the outcome analysis. Dinutuximab did not demonstrate evidence of efficacy as 11/39 patients remained event free for a DCR of 28.2% (95% CI 15-44.9%). One of 136 administered therapy cycles met criteria for unacceptable toxicity when a patient experienced sudden death of unknown cause. Other ≥ Grade 3 toxicities included pain, diarrhoea, hypoxia, and hypotension. Pharmacokinetic parameters were similar in the two schedules.

CONCLUSIONS

The combination of dinutuximab with GM-CSF did not significantly improve DCR in recurrent osteosarcoma. Dinutuximab toxicity and pharmacokinetics in adolescent and young adult osteosarcoma patients were similar to younger patients. Other strategies for targeting GD2 in osteosarcoma are being developed.

Molecular profiling identifies targeted therapy opportunities in pediatric solid cancer

To evaluate the clinical impact of molecular tumor profiling (MTP) with targeted sequencing panel tests, pediatric patients with extracranial solid tumors were enrolled in a prospective observational cohort study at 12 institutions. In the 345-patient analytical population, median age at diagnosis was 12 years (range 0-27.5); 298 patients (86%) had 1 or more alterations with potential for impact on care. Genomic alterations with diagnostic, prognostic or therapeutic significance were present in 61, 16 and 65% of patients, respectively. After return of the results, impact on care included 17 patients with a clarified diagnostic classification and 240 patients with an MTP result that could be used to select molecularly targeted therapy matched to identified alterations (MTT). Of the 29 patients who received MTT, 24% had an objective response or experienced durable clinical benefit; all but 1 of these patients received targeted therapy matched to a gene fusion. Of the diagnostic variants identified in 209 patients, 77% were gene fusions. MTP with targeted panel tests that includes fusion detection has a substantial clinical impact for young patients with solid tumors.

68 Ga-DOTATATE PET and functional imaging in pediatric pheochromocytoma and paraganglioma

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors in childhood. Up to 40% of PPGL are currently thought to be associated with a hereditary predisposition. Nuclear medicine imaging modalities such as fluorodeoxyglucose positron emission tomography (¹⁸ F-FDG PET), ⁶⁸ Ga-DOTATATE PET, and ¹²³ I-metaiodobenzylguanidine (¹²³ I-MIBG) scintigraphy play an essential role in the staging, response assessment, and determination of suitability for targeted radiotherapy in patients with PPGL. Each of these functional imaging modalities targets a different cellular characteristic and as such can be complementary to anatomic imaging and to each other. With the recent US Food and Drug Administration approval and increasing use of ⁶⁸ Ga-DOTATATE for imaging in children, the purpose of this article is to use a case-based approach to highlight both the advantages and limitations of DOTATATE imaging as it is compared to current radiologic imaging techniques in the staging and response assessment of pediatric PPGL, as well as other neuroendocrine malignancies.

Report of the First International Symposium on NUT Carcinoma

NUT carcinoma is a rare, aggressive cancer defined by rearrangements of the NUTM1 gene. No routinely effective treatments of NUT carcinoma exist, despite harboring a targetable oncoprotein, most commonly BRD4-NUT. The vast majority of cases are fatal. Poor awareness of the disease is a major obstacle to progress in the treatment of NUT carcinoma. While the incidence likely exceeds that of Ewing sarcoma, and BRD4-NUT heralded the bromodomain and extra-terminal domain (BET) inhibitor class of selective epigenetic modulators, NUT carcinoma is incorrectly perceived as "impossibly rare," and therefore receives comparatively little private or governmental funding or prioritization by pharma. To raise awareness, propagate scientific knowledge, and initiate a consensus on standard and targeted treatment of NUT carcinoma, we held the First International Symposium on NUT Carcinoma on March 3, 2021. This virtual event had more than eighty attendees from the Americas, Europe, Asia, and Australia. Patients with NUT carcinoma and family members were represented and shared perspectives. Broadly, the four areas discussed by experts in the field included (1) the biology of NUT carcinoma; (2) standard approaches to the treatment of NUT carcinoma; (3) results of clinical trials using BET inhibitors; and (4) future directions, including novel BET bromodomain inhibitors, combinatorial approaches, and immunotherapy. It was concluded that standard chemotherapeutic approaches and first-generation BET bromodomain inhibitors, the latter complicated by a narrow therapeutic window, are only modestly effective in a minority of cases. Nonetheless, emerging second-generation targeted inhibitors, novel rational synergistic combinations, and the incorporation of immuno-oncology approaches hold promise to improve the prognosis of this disease.

Racial, ethnic, and socioeconomic survival disparities among children with high-risk neuroblastoma treated on upfront Children’s Oncology Group clinical trials

10005

Background: Racial and socioeconomic disparities have not been comprehensively investigated in high-risk neuroblastoma (HR NBL). Prior Children’s Oncology Group (COG) investigations have demonstrated population-based disparities in late relapse rates among Black children, and trial-based disparities in relapse and survival among children living in poverty receiving post-consolidation immunotherapy. It is unknown whether these disparities persist in upfront trials for newly diagnosed patients. We leveraged COG data to investigate race, ethnicity, and socioeconomic disparities in a cohort of children with HR NBL treated on upfront clinical trials from 2007-2016. Methods: Retrospective cohort study of children enrolled on upfront COG HR NBL trials ANBL0532, ANBL09P1, and ANBL12P1. Race and ethnicity were the primary exposures categorized as: Black Non-Hispanic (BNH); Hispanic; Other Non-Hispanic (ONH); or White Non-Hispanic (WNH). Poverty was the secondary exposure, defined as household (public insurance only vs others), area (census-defined high-poverty ZIP code with >20% of population living below 100% Federal Poverty Level (FPL) vs <20% below 100% FPL), and rural (Census-defined rurality measures linked to ZIP code). Overall (OS) and event-free (EFS) survival from time of trial enrollment were plotted by Kaplan-Meier methods; associations with race/ethnicity and poverty were evaluated by log-rank tests. Results: Among 696 children, 16% were BNH, 11% Hispanic, 4% ONH, and 69% WNH. One-third (33%) of children were household poverty-exposed, 26% area poverty-exposed, and 15% rural-exposed. Tumor stage and biology did not differ by race/ethnicity or poverty measures. Five-year OS differed significantly by race/ethnicity (47% Hispanic vs. 50% ONH vs. 61% WNH vs. 62% BNH; p=0.047). Five-year OS was inferior among children exposed to household-poverty (53% vs. 63%; p=0.036) and neighborhood-poverty (54% vs. 62%; p=0.050) compared to unexposed children. There was no difference in OS by rurality. Similar directionality in 5-year EFS outcomes by race/ethnicity and poverty were observed without statistical significance. Conclusions: Race/ethnicity and poverty-exposure are associated with inferior OS outcomes among children with HR NBL despite uniform planned treatment on upfront COG trials. Investigation of mechanisms driving these disparities, including disparate early phase trial enrollment are ongoing to inform targeted health equity interventions to improve outcomes.

Predictors of differential outcomes according to response to induction chemotherapy in high-risk neuroblastoma

10032

Background: Response to induction chemotherapy has been shown to predict outcome in patients with high risk neuroblastoma, with those achieving a complete response (CR) having superior outcomes. Little is known about what factors impact survival within groups of patients with favorable and unfavorable end-induction response. We evaluated whether conventional prognostic factors remain prognostic in subsets of patients defined by response to induction. Methods: Patients from four COG high risk trials (A3973, ANBL02P1, ANBL0532, and ANBL12P1) were included. End-induction response was determined according to the 1993 International Neuroblastoma Response Criteria (INRC). Patients were categorized as having end-induction responses of CR, partial response (PR) or better, less than PR without progressive disease (PD), and PD. Univariate Cox models calculated OS hazard ratios for clinical and biological variables in subsets defined by response category. Results: 1,244 patients were included. Among all patients, age >5 years, INSS stage 4 disease, adrenal primary site and unfavorable histology by INPC were associated with inferior OS (see Table). Among patients who achieved a CR, stage 4 disease was the only factor that remained significantly associated with worse OS. Among those who achieved PR or better, age >5 years, stage 4 disease and unfavorable histology remained significantly associated with inferior OS. For those with less than PR but without PD, adrenal primary site, MYCN amplification and 1p LOH were significantly associated with inferior OS. For those with PD, MYCN amplification and 1p LOH were associated with worse OS, but older age was associated with better OS. Conclusions: Specific prognostic factors in neuroblastoma are associated with differential survival in groups defined by response to induction. Age, stage, and histology appear to be associated with OS for patients with more favorable response to induction, whereas MYCN and 1p LOH play a greater role in patients with unfavorable response to induction. These data can help to further define prognosis for patients with variable responses to induction. [Table: see text]

Efficacy and safety of larotrectinib in pediatric patients with tropomyosin receptor kinase (TRK) fusion-positive cancer: An expanded dataset

10030

Background: Neurotrophic tyrosine receptor kinase ( NTRK) gene fusions are oncogenic drivers in various tumor types across all ages. Larotrectinib is a first-in-class, central nervous system (CNS)-active, highly selective tropomyosin receptor kinase (TRK) inhibitor approved for pediatric and adult patients (pts) with TRK fusion-positive cancer, demonstrating an objective response rate (ORR) of 88% across 78 pediatric pts with non-CNS cancers (van Tilburg et al, SIOP 2021). We report an analysis of the efficacy and safety of larotrectinib in an expanded dataset of pediatric pts with TRK fusion-positive cancer. Methods: Pediatric pts (< 18 years) with non-CNS TRK fusion-positive cancer in larotrectinib clinical trials (NCT02637687, NCT02576431) were included and ORR (RECIST v1.1) was investigator (INV)-assessed. Data cut-off was July 20, 2021. Results: A total of 94 pts were included in this analysis. Tumor types included infantile fibrosarcoma (52%), other soft tissue sarcoma (40%), congenital mesoblastic nephroma (2%), thyroid cancer (2%), bone sarcoma (1%), breast cancer (1%), and melanoma (1%). Pts had gene fusions involving NTRK1 (43%), NTRK2 (3%), or NTRK3 (54%). Median age was 2.2 years (range 0–18 years). Of the 62 (66%) pts who received prior systemic therapy, 32 (52%) received ≥2 lines. The INV-assessed best ORR for the 93 evaluable pts was 84% (95% confidence interval [CI] 75–91): 35 (38%) complete response (CR; including two pending confirmation and 10 pathological CR), 43 (46%) partial response (two pending confirmation), 11 (12%) stable disease, two (2%) progressive disease, and two (2%) not determined. The median time to response was 1.8 months. Overall, median duration of response was 43.3 months (95% CI 23.4–NE); median follow-up was 26.0 months. Median progression-free survival and overall survival (OS) were 37.4 months (95% CI 22–NE) and not reached, respectively; median follow-up was 21.2 and 30.3 months, respectively. The 36-month OS rate was 93% (95% CI 86–99). Treatment duration ranged from 1+ to 63+ months. At data cut-off, 31 pts had progressed; 18 continued treatment post-progression for ≥4 weeks. There were no treatment-related deaths. Treatment-related adverse events (TRAEs) occurred in 81% of pts (23% were Grade [G] 1, 28% G2, 25% G3, and 5% G4). The most common TRAE was increased aspartate aminotransferase (31 pts [33%]). Four pts (4%) discontinued treatment due to TRAEs. Neurological TRAEs occurred in 12% of pts (5% were G1, 4% G2, and 2% G3). The most common neurological TRAE was headache (5 pts [5%]). Conclusions: In this expanded dataset, larotrectinib continues to demonstrate rapid and durable tumor-agnostic efficacy, extended survival, and a favorable safety profile in pediatric pts with TRK fusion-positive cancer. These results highlight the importance of identifying NTRK gene fusions in pediatric solid tumors. Clinical trial information: NCT02576431, NCT02637687.

Modulation of radiation biomarkers in a randomized phase II study of 131I-MIBG with or without radiation sensitizers for relapsed or refractory neuroblastoma: A report from the NANT Consortium

10026

Background: 131I-metaiodobenzylguanidine (131I-MIBG) has demonstrated efficacy as a single agent for patients with neuroblastoma. Recent trials have focused on 131I-MIBG combination strategies, though little is known about the impact of combination agents on markers of radiation exposure. Methods: NANT11-01 (NCT02035137) was a multicenter, open label, randomized phase II clinical trial that evaluated 131I-MIBG therapy alone (Arm A) or in combination with vincristine/irinotecan (Arm B) or vorinostat (Arm C) for patients with resistant/relapsed neuroblastoma. We collected blood samples at baseline, 72 hours, 96 hours, and 15 days after 131I-MIBG infusion and determined levels of plasma FLT3 ligand, serum amylase, and gene expression for selected RNA transcripts (apoptosis, DNA damage response and cell cycle related). We evaluated marker association with treatment arm, clinical response using NANT response criteria, toxicity, and whole-body radiation dose. Results: The cohort included 99 patients who had at least one biomarker available for analysis (32 Arm A; 35 Arm B; 32 Arm C). We observed both positive and negative significant modulation in most biomarkers between baseline, 72 hours, and 96 hours following 131I-MIBG. Patients in Arm C had the lowest degree of modulation in FLT3 ligand. Elevated baseline levels of FLT3 ligand were significantly associated with improved Curie response but not overall response. Lower baseline BCL2 levels were associated with higher overall and Curie response. Patients with increased 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 (BCL2/L1 and BAX) was significantly associated with grade 4 hematological toxicity. Whole-body radiation dose and PRKDC fold change at 72 hours were significantly correlated. No other individual biomarkers were correlated with whole body radiation dose at 72 or 96 hours post 131I-MIBG. Conclusions: Peripheral blood biomarkers relevant to radiation exposure demonstrate significant modulation over time after 131I-MIBG treatment. Biomarkers related to hematopoietic damage and apoptosis were associated with hematological toxicity. Patients treated with vorinostat and 31I-MIBG had differential modulation of FLT3-ligand Further use of these biomarkers may improve our ability to care for patients treated with 131I-MIBG.

Clinical and biologic predictors of response to MIBG therapy: A report from the new approaches to neuroblastoma therapy (NANT) consortium

e22003

Background: 131I-metaiodobenzylguanidine (MIBG) remains one of the most active agents for neuroblastoma. The clinical and biologic predictors of response to MIBG therapy have not been systematically characterized in a recent era trial. Methods: Patients 1-30 years were enrolled on the randomized phase 2 trial of MIBG vs. MIBG/vincristine/irinotecan vs. MIBG/vorinostat for relapsed/refractory neuroblastoma (NANT2011-01, NCT02035137) between 2014-2019. Data were compared between those who had an objective response (partial response or better using NANT response criteria) to MIBG after the first cycle and those who did not according to clinical features (age at study enrollment; sex; response to prior therapy; prior receipt of MIBG therapy; bone marrow involvement at study enrollment; and measurable disease status at study enrollment) and MYCN status. Univariate analyses were performed using odds ratio and Fisher exact tests. Multivariate logistic regression analysis was used to identify predictors of response to MIBG therapy while controlling for key confounders. Results: 105 response-evaluable patients were included in the analytic cohort. Across the 3 study arms, 20% (21/105) had an objective response to the treatment. Only measurable disease status was statistically significantly associated with response to therapy, with higher rates of response among patients without measurable disease at study enrollment (30% vs. 13%, p = 0.049). Response to prior therapy, sex, MYCN status, and measurable disease status showed univariate odds ratios of 2 or greater (Table). Only measurable disease status remained statistically significant in the multivariate analysis (p = 0.043, Table). Conclusions: Patients without measurable disease have a higher rate of objective responses to MIBG therapy. Understanding these differences based upon predictors of response may help to inform stratification methods for future MIBG clinical trials.[Table: see text]

A pilot induction regimen incorporating dinutuximab and sargramostim for the treatment of newly diagnosed high-risk neuroblastoma: A report from the Children's Oncology Group

10003

Background: The addition of dinutuximab (DIN) in the post-consolidation setting led to improved event-free survival rates for patients with high-risk neuroblastoma. Chemoimmunotherapy including irinotecan, temozolomide, DIN and sargramostim (GM-CSF) in patients with recurrent or refractory neuroblastoma results in robust objective clinical responses. Evaluation of chemoimmunotherapy in the induction setting for patients with newly-diagnosed high-risk neuroblastoma (HR-NBL) warrants investigation. Methods: Children’s Oncology Group (COG) ANBL17P1 is a prospective, single arm, limited institution pilot study to assess the tolerability and feasibility of administering DIN (17.5mg/m2/dose, IV Days 2-5) and GM-CSF (250mcg/m2/dose, subcutaneous Days 6-count recovery) with COG Induction chemotherapy Cycles 3-5 for patients with newly-diagnosed high-risk neuroblastoma. The primary endpoint of tolerability included the number of toxic deaths and number of patients experiencing predefined unacceptable toxicities during Induction Cycles 3-5. Unacceptable toxicities included: hypotension requiring pressors > 24 hours, respiratory toxicity requiring ventilatory support > 24 hours, Grade 4 neuropathy that did not resolve prior to the next cycle, and failure to recover the ANC to > 750 mm3 by day 35. Feasibility was assessed as being able to receive > 75% of planned DIN doses administered during Induction Cycles 3-5. Revised International Neuroblastoma Response Criteria (INRC) were used to assess end of Induction (EOI) response. Results: Forty-two eligible and evaluable patients with newly-diagnosed high-risk neuroblastoma enrolled at 8 sites (22 [52.4%] males; median age 3.3 years at diagnosis) from January 14, 2019 to June 4, 2020. The most common DIN related Grade >3 toxicities observed during Induction Cycles 3-5 included fever (31.0%) and pain (9.5%). None of the patients experienced a toxic death or unacceptable toxicity during Induction Cycles 3-5. Thus, the regimen was deemed tolerable. Patients received 97.4% - 101.8% of the total DIN dose expected to be administered during Induction Cycles 3-5. Therefore, the regimen was deemed feasible. Thirty-eight of 42 patients completed the EOI evaluations, including 11 with complete response, 22 with partial response, 0 with minor response, 3 with stable disease and 2 with progressive disease. The overall EOI objective response rate (CR+PR+MR) was 86.8%. Conclusions: The administration of DIN and GM-CSF to COG Induction Cycles 3-5 for patients with newly-diagnosed high-risk neuroblastoma was tolerable and feasible. The objective response rate at EOI appears encouraging. This therapeutic regimen will be studied in a randomized phase 3 trial to further evaluate the efficacy of Induction phase chemoimmunotherapy for high-risk neuroblastoma. Clinical trial information: NCT03786783.

Clinical and biological features prognostic of survival after relapse of INRGSS-stage MS pattern neuroblastoma: A report from the International Neuroblastoma Risk Group (INRG) project

10044

Background: Neuroblastoma (NB) presenting with INRGSS MS metastatic pattern highlights the extreme heterogeneity within NB and subsequent difficulty in risk assignment. Depending on tumor biology, patients with stage MS disease may be classified as very-low risk or as high-risk. While outcomes at initial diagnosis have been well-described, outcomes after relapse are less well defined. Methods: From the INRG Data Commons, we investigated clinical and biological characteristics of patients diagnosed 1984-2021 with stage MS pattern NB (INSS stage 4s, INSS stage 4 or INRG stage MS) who subsequently experienced disease relapse or progression, excluding patients whose first event was death. Using Kaplan-Meier methods, post-relapse overall survival (OS)± standard error (SE) was calculated from the time of first relapse/progression until death or last contact, overall and by era of diagnosis: < 2000 vs ≥2001. Univariate Cox models were used to identify factors prognostic of post-relapse OS. Results: 209 patients met eligibility criteria,103 diagnosed < 2001 and 106 ≥2001. Of patients diagnosed ≥2001, 89% (n = 94) were < 365 days old at diagnosis; tumors were MYCN amplified in 21% (21/102) and diploid in 31% (20/64). Of this same cohort, time from initial diagnosis to relapse was < 6 months in 40% (n = 42), 6-12 months in 25% (n = 26), and > 12 months in 36% (n = 38) of patients. Of 60 patients with known site of relapse/progression diagnosed ≥2001, 73% (44) were metastatic (29) or primary plus metastatic (15). Among these, 16% (5/32) remained stage MS pattern while 84% (27/32) had metastatic sites beyond MS sites. Five-year post-relapse OS±SE was 53±3.5% overall (n = 209), and higher for those diagnosed ≥2001 (62±5.0%; n = 106) compared to those diagnosed < 2001 (44±4.9%; n = 103) (p = 0.0046). In patients diagnosed ≥2001, factors prognostic of superior post-relapse OS included: age < 365 days; not Hispanic; MYCN non-amplified; no 1p loss/aberration, hyperdiploidy; low/intermediate MKI; LDH < 1400 U/L, favorable INPC histology; and < 12 months from initial diagnosis to first relapse. Conclusions: Most patients with relapsed stage MS NB have metastatic relapse and these relapses more commonly occur at sites outside liver, skin, and bone marrow. Patients diagnosed ≥2001 with MS pattern NB have substantially better post-relapse OS compared to those diagnosed < 2001. In the cohort of patients with MS pattern NB diagnosed ≥2001, most of the well-accepted prognostic factors for OS at diagnosis are also prognostic of post-relapse OS.

Phase 2 trial of palbociclib and ganitumab in patients with relapsed Ewing sarcoma

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Background: Ewing sarcoma (EwS) is an aggressive sarcoma with few treatment options for patients with relapsed disease. CDK4 is a known genomic vulnerability in EwS, but an unappealing monotherapy target given propensity for innate resistance. In laboratory studies to identify targets synergistic with CDK4 inhibition, IGF-1R scored highly. We present the results of a phase 2 study combining palbociclib (CDK4/6 inhibitor) with ganitumab (IGF-1R monoclonal antibody) for patients with relapsed or refractory EwS. Methods: This was a prospective open-label, non-randomized, single-center, phase 2 study (NCT04129151) for patients with relapsed EwS and RECIST measurable disease. Patients with relapsed EwS ≥12 years and a documented fusion consistent with EwS were eligible. Patients initially received Palbociclib 125 mg on days 1-21 and ganitumab 18 mg/kg on days 1 and 15 of a 28-day cycle. The primary endpoints were objective response (complete or partial) per RECIST and toxicity by CTCAE. Secondary endpoints included progression-free survival (PFS) and overall survival (OS). A one-stage design required ≥4 responders out of 15 to evaluate an alternative hypothesis of 40% response rate against a null of 10%. Results: Ten evaluable patients enrolled between 5/2019-8/2021. The study closed 12/2021 due to lack of ganitumab drug supply. The median age at enrollment was 25.7 years (range 12.3-40.1; Table). The median duration of therapy was 2.5 months (range = 0.9-10.8). There were no complete or partial responders. Three of 10 patients had stable disease for > 4 cycles and 2 had stable disease at completion of planned therapy or study closure. 6-month PFS was 30±14.5%. Two patients had cycle 1 hematologic DLTs triggering the pre-defined toxicity rule; the palbociclib dose was subsequently reduced to 100 mg daily for 21 days. Among the remaining 8 patients, two had cycle 1 hematologic DLTs at the 100 mg dose. 80% of patients had grade 3/4 AEs; the most commons AEs were neutropenia (n = 8), white blood cell decreased (n = 7), and thrombocytopenia (n = 5). Total IGF-1 testing demonstrated intrapatient elevations in serum levels after a single cycle of therapy. Analysis of serial ctDNA samples is ongoing. Conclusions: Four responders out of 15 were required to reject the null hypothesis of a 10% response rate. With 0/10 responders, we concluded that this combination lacked adequate therapeutic activity for further study. The combination was tolerable at a palbociclib dose of 100 mg, with primarily hematologic toxicity in patients with relapsed EwS. Clinical trial information: NCT04129151. [Table: see text]

Long-term outcomes in patients with localized Ewing sarcoma treated with interval-compressed chemotherapy: A long-term follow-up report from Children’s Oncology Group study AEWS0031

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Background: Children’s Oncology Group study AEWS0031 demonstrated superior 5-year event-free survival (EFS) in patients with localized Ewing sarcoma (ES) receiving interval-compressed (IC) chemotherapy (every 2 weeks) compared to standard timing (ST) chemotherapy (every 3 weeks). We assessed the long-term outcome of patients treated on AEWS0031 to determine whether the survival advantage of IC chemotherapy was maintained at 10 years. Methods: AEWS0031 enrolled 568 eligible patients with localized ES. Patients were stratified into four groups by age (<18 years and ≥ 18 years) and primary site (pelvic and non-pelvic), and randomized to receive 14 cycles of alternating vincristine-doxorubicin-cyclophosphamide and ifosfamide-etoposide given every 3 weeks (ST; Regimen A) vs. every 2 weeks (IC; Regimen B). For this updated report, one patient was excluded due to uncertainty of original diagnosis giving a total of 567 patients in this analysis. Data for tumor measurements and histologic response were collected retrospectively from institutional reports. EFS and overall survival (OS) were estimated using the Kaplan-Meier method and compared using the log-rank test and Gray’s test for cumulative incidence (CI). Results: The 10-year EFS for patients treated with IC chemo was 70% compared to 61% for ST chemo (p = 0.03), and the OS was 76% with IC chemo compared to 69% for ST chemo (p = 0.03). The 10-year CI of second malignant neoplasms (SMNs) for ST chemo was 4.2% [95% confidence interval: 2.4-7.5] compared to 3.2% (95% confidence interval: 1.6-6.3) for IC chemo (p = 0.5). There was a trend towards improved 10-year EFS in those receiving IC chemo both with non-pelvic (N = 477; 71% vs. 64%) and pelvic (N = 90; 67% vs. 43%) primary tumors. Similarly, the 10-year EFS was superior for patients treated with IC chemo in both the < 18 years (N = 500; 73% vs. 64%) and ≥ 18 years (N = 67; 53% vs. 37%) age groups. Among the 184 patients with available histologic response data, the 10-year EFS from the time of local control was 76% for those with < 10% viable tumor and 56% for those with ≥ 10% viable tumor (p = 0.01). Additional analysis comparing patients with any viable tumor vs. no viable tumor (NVT) by treatment regimen demonstrated that patients with NVT who received IC chemo had 10-year EFS and OS from local control of 91% and 97%, respectively. In the 210 patients for whom tumor volume calculations were possible, there was no difference in the 10-year EFS for patients with tumors < 200 mL vs. ≥ 200 mL. Conclusions: With longer term follow-up, IC chemotherapy for localized ES is associated with superior EFS and OS without an increase in SMNs. This study suggests patients ≥ 18 years with poor necrosis or pelvic primary tumors remain at high risk for relapse despite IC chemo, emphasizing the need for alternative treatment strategies to improve their outcomes. Clinical trial information: NCT00006734.

Phase I study of 131I-MIBG with dinutuximab for patients with relapsed or refractory neuroblastoma: A report from the new approaches to neuroblastoma therapy (NANT) consortium

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Background: 131I-metaiodobenzylguanidine (MIBG) is one of the most active salvage therapies for patients with relapsed or refractory (R/R) high-risk neuroblastoma (HRNB). Preclinical neuroblastoma studies show cooperative effects when radiation is combined with anti-GD2 monoclonal antibody (mAb). We hypothesized that MIBG would synergize with the anti-GD2 mAb dinutuximab to provide improved anti-tumor responses. The primary aims of Part A of this study were to determine the maximum tolerated dose (MTD) and/or recommended Phase II dose (RP2D) of MIBG administered with dinutuximab in children with R/R HRNB and to define and describe the toxicities. Methods: Patients 1-29 years of age with R/R HRNB who had MIBG uptake in ≥ 1 site were eligible. Prior anti-GD2 mAb therapy was allowed provided it was not administered with MIBG and not permanently discontinued due to toxicity. One prior MIBG therapy was allowed. MIBG was administered on day 1 at one of three dose levels (DLs): 12, 15, and 18 mCi/kg (DL1-DL3, respectively) with an expansion cohort at the RP2D. Doses were escalated using a rolling six design starting at DL1. The primary endpoint was dose-limiting toxicity (DLT) during course 1. Dinutuximab (17.5 mg/m2/dose) was administered intravenously on days 8-11 and 29-32 and GM-CSF (250 mcg/m2/dose) subcutaneously on days 8-17 and 29-38. Autologous peripheral blood stem cells were infused to all patients on day 15 (+/- 2 days). A maximum of 2 courses per patient were allowed. Response rate was defined as the proportion of patients with a complete or partial response. Results: Thirty-one patients were enrolled. Fourteen were evaluable for dose escalation (4 on DL1, 4 on DL2, and 6 on DL3); 5 evaluable patients were treated in the DL3 expansion. The median age was 7.4 years (range: 3.1 – 22.0) and 20 (65%) were male. Twenty-seven (87%) patients had previously received a median of 8.5 cycles of chemoimmunotherapy (range: 2 – 21). Eight patients previously progressed while receiving anti-GD2 mAb including 7 in DL3. Five (16%) patients had previously received MIBG. No patient at any dose level experienced DLT. Common grade 3/4 treatment-related toxicities were expected hematologic toxicities attributable to MIBG and non-hematologic toxicities attributable to dinutuximab or GM-CSF. Among 26 response-evaluable patients, the centrally-confirmed response rate was 31% across all dose levels: 2/6 (33%) in DL1, 3/5 (60%) in DL2, and 3/15 (20%) in DL3. There were 3 minor responses, 1 in DL2 and 2 in DL3. Conclusions: The RP2D of MIBG in combination with standard doses of dinutuximab and GM-CSF is 18 mCi/kg. This radioimmunotherapy regimen is well-tolerated without additive toxicity. Preliminary efficacy data are encouraging in this heavily pre-treated patient population. A phase 2 trial of this regimen is planned in patients with R/R HRNB. Clinical trial information: NCT03332667.

Clinical development of new drugs for adults and children with cancer in 2010-2020: Longitudinal study of investigational drugs

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Background: Many investigational drugs start clinical testing to evaluate potential therapeutic benefits for oncology patients, but few eventually receive FDA approval. Moreover, only a small number is evaluated in pediatric populations, potentially contributing to the paucity of new approved drugs for young patients with cancer. Limited information is available on the development pipeline of investigational drugs, including the range of drug types entering clinical trials, trial phases at which development stalls, or rate of regulatory approval. To inform current clinical development efforts, we characterized the development and outcomes for a comprehensive sample of New Molecular Entities (NMEs) that started clinical testing worldwide in 2010-2015. Methods: We performed a longitudinal study using AdisInsight, a commercial database of global pharmaceutical research and development. This is a comprehensive database of drug development activity, which collects and curates data from trial registries, conference proceedings, journal publications, and press releases. Using these data, we identified all NMEs starting their first clinical trial for an oncology indication in 2010-2015. We followed each NME from the start of its first phase I trial to the end of 2020, and identified all associated trials, final development status, and FDA deliberations. We classified trials as pediatric-eligible if patients aged < 18 years were eligible for participation. We used the Drugs@FDA website to identify all FDA actions, including marketing approvals and requests for pediatric trials under pediatric programs (i.e. BPCA requests or PREA requirements). Results: A total of 572 NMEs started initial phase I clinical trials in 2010-2015. Among these, the most studied classes were small molecules (N, %: 316, 55%), antibodies (148, 26%), and antibody-drug conjugates (44, 8%). Overall, the NMEs were studied in 6,141 clinical trials by the end of 2020, with a median of 3 trials per NME. The highest pre-approval development phase reached by an NME was phase I for 325 (57%), phase II for 153 (27%), and phase III for 94 (16%). Only 39 NMEs (7%) were approved by the FDA by the end of 2020. Among approved NMEs, the median time (range) from start of first phase I trial to date of first approval was 6 (3-10) years. Among all NMEs, only 67 (12%) were tested in pediatric-eligible trials by the end of 2020, and 5 (< 1%) were approved for use in selected pediatric populations. Three of these had been subject to BPCA requests, and all had PREA requirements waived. Conclusions: More efficient clinical development strategies are needed to accelerate the production of new cancer therapies, especially for children. Analyses such as this one should be conducted regularly to help identify areas in need of innovation and to assess the potential impact of regulatory initiatives (e.g. the RACE act, effective since August 2020).

Histologic characterization of pediatric mesenchymal neoplasms treated with kinase-targeted therapy

AIMS

Recurrent alterations involving receptor tyrosine or cytoplasmic kinase genes have been described in soft tissue neoplasms such as infantile fibrosarcoma (IFS) and inflammatory myofibroblastic tumor (IMT). Recent trials and regulatory approvals for targeted inhibitors against the kinase domains of these oncoproteins have allowed for increased use of targeted therapies. We aimed to characterize the histologic features of pediatric mesenchymal neoplasms with kinase alterations treated with targeted inhibitors.

METHODS AND RESULTS

Eight patients with tyrosine kinase-altered mesenchymal neoplasms with pre- and post-treatment samples were identified. Tumors occurred in 5 females and 3 males with a median age at presentation of 6.5 years. Tumor sites were bone/somatic soft tissue (n=5) and viscera (n=3). Pre-treatment diagnoses were: IMT (n=3), epithelioid inflammatory myofibroblastic sarcoma (n=1), and descriptive diagnoses (n=4) such as "kinase-driven spindle cell tumor". Fusions identified were ETV6::NTRK3 (n=2), TPM3::NTRK1, SEPT7::BRAF, TFG::ROS1, KLC1::ALK, RANBP2::ALK, and MAP4::RAF1. Patients were treated with larotrectinib (n=3), ALK or ALK/ROS1 inhibitors (n=3), and MEK inhibitors (n=2). Post-treatment tumors exhibited a striking decrease in cellularity (7/8) and the presence of collagenous stroma (7/8) with extensive glassy hyalinization (5/8). In two cases, abundant coarse or psammomatous calcifications were seen and in one case prominent perivascular hyalinization was noted. Residual viable tumor was seen in 3/8 cases (<5% in one case, and >75% in 2/8 cases).

CONCLUSIONS

Mesenchymal neoplasms with tyrosine kinase alterations treated with targeted inhibitors show pathologic response, which includes decreased cellularity and stromal hyalinization. The presence of these features may be helpful in assessing tumor response after targeted therapy.

High-Risk and Relapsed Neuroblastoma: Toward More Cures and Better Outcomes

Approximately half of the patients diagnosed with neuroblastoma are classified as having high-risk disease. This group continues to have inadequate cure rates despite multiagent chemotherapy, surgery, high-dose chemotherapy with autologous stem cell rescue, and immunotherapy directed against GD2. We review current efforts to try to improve outcomes in patients with newly diagnosed disease by integrating novel targeted therapies earlier in the course of the disease. We further examine a growing list of options available for patients with relapsed or refractory high-risk disease, with an eye toward graduating successful strategies from a relapsed/refractory setting to the frontline setting. Last, we review efforts to study and potentially mitigate the array of late effects faced by survivors of high-risk neuroblastoma.

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.

Phase III Trial Adding Vincristine-Topotecan-Cyclophosphamide to the Initial Treatment of Patients With Nonmetastatic Ewing Sarcoma: A Children's Oncology Group Report

PURPOSE

The primary aim of this phase III randomized trial was to test whether the addition of vincristine, topotecan, and cyclophosphamide (VTC) to interval compressed chemotherapy improved survival outcomes for patients with previously untreated nonmetastatic Ewing sarcoma.

METHODS

Patients were randomly assigned to receive standard five-drug interval compressed chemotherapy (regimen A) for 17 cycles or experimental therapy with five cycles of VTC within the 17 cycles (regimen B). Patients were stratified by age at diagnosis (< 18 years and ≥18 years) and tumor site (pelvic bone, nonpelvic bone, and extraosseous). Tumor volume at diagnosis was categorized as < 200 mL or ≥ 200 mL. Local control occurred following six cycles. Histologic response was categorized as no viable or any viable tumor. Event-free survival (EFS) and overall survival (OS) were compared between randomized groups with stratified log-rank tests.

RESULTS

Of 642 enrolled patients, 309 eligible patients received standard and 320 received experimental therapy. The 5-year EFS and OS were 78% and 87%, respectively. There was no difference in survival outcomes between randomized groups (5-year EFS regimen A v regimen B, 78% v 79%; P = .192; 5-year OS 86% v 88%; P = .159). Age and primary site did not affect the risk of an EFS event. However, age ≥ 18 years was associated with an increased risk of death at 5 years (hazard ratio 1.84; 95% CI, 1.15 to 2.96; P = .009). The 5-year EFS rates for patients with pelvic, nonpelvic bone, and extraosseous primary tumors were 75%, 78%, and 85%, respectively. Tumor volume ≥ 200 mL was significantly associated with lower EFS.

CONCLUSION

While VTC added to five-drug interval compressed chemotherapy did not improve survival, these outcomes represent the best survival estimates to date for patients with previously untreated nonmetastatic Ewing sarcoma.

Molecular Characterization of Inflammatory Tumors Facilitates Initiation of Effective Therapy

Inflammatory myofibroblastic tumor (IMT) is a rare, mesenchymal tumor that has an increased incidence in childhood. Tumors are usually isolated to the chest, abdomen, and retroperitoneum, but metastatic presentations can be seen. Presenting symptoms are nonspecific and include fever, weight loss, pain, shortness of breath, and cough. Approximately 85% of IMTs harbor actionable kinase fusions. The diagnosis can be delayed because of overlapping features with inflammatory disorders, such as elevated inflammatory markers, increased immunoglobin G levels, fever, weight loss, and morphologic similarity with nonmalignant conditions. We present a girl aged 11 years with a TFG-ROS1 fusion-positive tumor of the lung that was initially diagnosed as an immunoglobin G4-related inflammatory pseudotumor. She underwent complete left-sided pneumonectomy and later recurred with widely metastatic disease. We then report the case of a boy aged 9 years with widely metastatic TFG-ROS1 fusion-positive IMT with rapid molecular diagnosis. In both children, there was an excellent response to oral targeted therapy. These cases reveal that rapid molecular testing of inflammatory tumors is not only important for diagnosis but also reveals therapeutic opportunities. Targeted inhibitors produce significant radiologic responses, enabling potentially curative treatment approaches for metastatic ROS1 fusion IMT with previously limited treatment options. Primary care pediatricians and pediatric subspecialists have a crucial role in the early consultation of a pediatric oncology center experienced in molecular diagnostics to facilitate a comprehensive evaluation for children with inflammatory tumors.