Children's Oncology Group Trial Research Articles

Outcome of children and young adults with localized extremity rhabdomyosarcoma treated on Children's Oncology Group trials.

10006 Background: Extremity rhabdomyosarcoma (RMS) accounts for 15-20% of patients with localized RMS. The long-term survival and associated prognostic factors of extremity RMS patients treated on the contemporary Children’s Oncology Group (COG) trials have not been reported. Methods: Patients with localized extremity RMS enrolled on the D9602, D9803, ARST0331 and ARST0531 COG trials were analyzed. The Kaplan-Meyer method estimated event-free (EFS) and overall survival (OS). The Log-rank test and Cox regression were used to estimate the prognostic significance of age at diagnosis, sex, race, tumor site & size, IRS group, stage, histology, FOXO1 fusion status, anaplasia, lymph node involvement, delayed primary excision (DPE) and radiation on survival. Results: We identified 159 patients with localized extremity RMS; 108 (68%) were < 10 years at diagnosis, 84(53%) had primary tumor > 5 cm, and 35 (22%) and 98 (62%) had IRS group II and III disease. Histology was alveolar in 106 (67%), and 43 (27%) had regional lymph node involvement on imaging or pathology. Seventeen were treated on low-risk (LR) studies D9602 (N = 10) and ARST0331 (N = 7), whereas 142 were treated on intermediate-risk (IR) trials D9803 (N = 85) and ARST0531 (N = 57). Eighty patients (50%) underwent primary surgical excision and 121 (76%) received radiotherapy. DPE was attempted in 60 patients (38%), resulting in an R0 (microscopically negative) margin in 48 (80%). Relapse/progression occurred in 52 patients: metastatic 26 (50%), local 22 (42%), and combined 3(6%). The 5-year EFS and OS of the whole cohort were 62.6% (95% CI: 54%-71.2%) and 78.7%% (95%CI: 71.4%-85.9%). LR patients treated on D9602 and ARST0331 trials had comparable 5-year EFS (70% vs. 71.4%, p-0.90) and OS (90% vs. 85.7%, p-0.54), respectively, while IR patients had significantly better 5-year EFS (68.9% vs. 51%, p-0.023) and OS (86.2% vs. 64.4%, p-0.007) on D9803 trial than ARST0531 trial. The 5-year EFS and OS of IRS group III patients with DPE with R0 margins were comparable to IRS group II patients (70.4% vs. 66.6%) & (86.5% vs. 84.6%), respectively. On univariable analysis, age at diagnosis and sex were associated with EFS, while age at diagnosis, sex, tumor size, IRS group, stage and fusion status were associated with OS (p < 0.05). None of the analyzed factors demonstrated independent statistical association with EFS, whereas female sex was the only factor independently associated with OS [Hazard ratio (HR): 0.4, 95% CI 0.20-0.85)]. Conclusions: IR localized extremity RMS patients treated on ARST0531 had suboptimal outcome. Survival of IRS group III patients with R0 DPE was comparable to IRS group II patients. Females with localized extremity RMS had better OS than males. Clinical trial information: NCT00354835 ; NCT00003958 ; NCT00075582 ; NCT00002995 .

Chemotherapy in pediatric low-grade gliomas (PLGG).

Pediatric low-grade gliomas (PLGG) are commonly treated with a combination of surgery, radiotherapy, and chemotherapy. Recent trends prioritize reducing long-term morbidities, particularly in younger patients. While historically chemotherapy was reserved for cases progressing after radiotherapy, evolving recommendations now advocate for its early use, particularly in younger age groups. The carboplatin and vincristine (CV) combination stands as a standard systemic therapy for PLGG, varying in dosage and administration between North America and Europe. Clinical trials have shown promising response rates, albeit with varying toxicity profiles. Vinblastine has emerged as another effective regimen with minimal toxicity. TPCV, a regimen combining thioguanine, procarbazine, lomustine, and vincristine, was compared to CV in a Children's Oncology Group trial, showing comparable outcomes, but more toxicity. Vinorelbine, temozolomide, and metronomic chemotherapy have also been explored, with varied success rates and toxicity profiles. Around 40-50% of PLGG patients require subsequent chemotherapy lines. Studies have shown varied efficacy in subsequent lines, with NF1 patients generally exhibiting better outcomes. The identification of molecular drivers like BRAF mutations has led to targeted therapies' development, showing promise in specific molecular subgroups. Trials comparing targeted therapy to conventional chemotherapy aim to delineate optimal treatment strategies based on molecular profiles. The landscape of chemotherapy in PLGG is evolving, with a growing focus on molecular subtyping and targeted therapies. Understanding the role of chemotherapy in conjunction with novel treatments is crucial for optimizing outcomes in pediatric patients with low-grade gliomas.

Outcome of patients with relapsed or refractory nonrhabdomyosarcoma soft tissue sarcomas enrolled in phase 2 cooperative group clinical trials: A report from the Children's Oncology Group.

The aim of this study was to estimate the event-free survival (EFS) of children and young adults with relapsed or refractory nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) treated in nonrandomized phase 2 studies conducted by the Children's Oncology Group (COG) and predecessor groups to establish a benchmark EFS for future phase 2 NRSTS trials evaluating the activity of novel agents. A retrospective analysis of patients with recurrent or refractory NRSTS prospectively enrolled in nonrandomized phase 2 COG and predecessor group trials between 1994 and 2015 was conducted. EFS was defined as disease progression/relapse or death and calculated via the Kaplan-Meier method. The log-rank test and relative risk regression were used to compare EFS distribution by age at enrollment, sex, race, NRSTS histology, prior lines of therapy, calendar year of trial, and type of radiographic response. In total, 137 patients were enrolled in 13 phase 2 trials. All trials used radiographic response rate as a primary outcome, and none of the agents used were considered active on the basis of trial-specified thresholds. The estimated median EFS and 6-month EFS of the entire study cohort was 1.5 months (95% confidence interval [CI], 1.3-1.8 months) and 19.4% (95% CI, 12.7%-26%), respectively. No difference in EFS was observed by age at enrollment, sex, race, NRSTS histology subtype, prior lines of therapies, and trial initiation year. EFS significantly differed by radiographic response. The EFS for children and young adults with relapsed or refractory NRSTS remains suboptimal. Established EFS can be referenced as a benchmark for future single-agent phase 2 trials incorporating potentially active novel agents in this population.

Identifying Tumor-Specific Immune Response and Biomarkers of High-Risk Hodgkin Lymphoma Patients Treated with and without Brentuximab on Children's Oncology Group Trial AHOD1331

Introduction: There is an unmet need to examine anti-tumor immune responses and predictive biomarkers in the peripheral blood to guide effective combination immunotherapies in classic Hodgkin Lymphoma (cHL). We hypothesized that treatment with the anti-CD30 antibody drug conjugate brentuximab vedotin (Bv) in combination with chemotherapy will have dual therapeutic effects in HL, with direct antiproliferative effects and a restoration of favorable tumor specific cytotoxic T cell immune response. We evaluated tumor-specific cytotoxic T cell response, cytokine and chemokine milieu in the peripheral blood of pediatric patients with HL before and after treatment with either standard chemotherapy or chemotherapy + Bv. Methods: Children's Oncology Group clinical trial AHOD1331 was a randomized phase III trial for newly diagnosed high risk cHL ages ≥2 to 22 years which compared standard chemotherapy with doxorubicin, bleomycin, etoposide, prednisone and cyclophosphamide (ABVE-PC) to Bv + AVE-PC with response adapted radiation. Peripheral blood samples were collected at diagnosis (pre) and following completion of treatment (post). Peripheral blood mononuclear cells and plasma were isolated using Ficoll Density gradient. Plasma was cryopreserved for batch testing of Th1/Th2 cytokines, sCD30, sCD163 and TARC by Luminex assay. Cytotoxic T cell responses to non-EBV HL specific tumor associated antigens (TAAs) MAGEA4, PRAME, and survivin pre and post treatment were tested using the interferon-γ ELISPOT assay after ex vivo expansion. TAA-T cell specificity was reported as spot forming count (SFC per 10 5 T cells). Changes in cytokine levels and T cell responses pre versus post treatment were compared using paired t-tests and blinded to treatment arm.Levels of sCD30, sCD163 and TARC were compared both pre and post treatment. Thecox model was used to evaluate association between levels and event free survival (EFS) across both arms. Results There was no difference in patient or disease characteristics between the entire study cohort (n=587) and patients analyzed (n=216). There were 184 patients with pre and post cytokine data, 71 patients with pre and post ELISPOT-T cell data, 147 patients with pre and post sCD30/sCD163 data, and 146 with pre and post TARC data. Compared to pre-treatment levels, there was a significant reduction in the immunosuppressive cytokines IL-13 (p=0.004) and increase in pro-inflammatory cytokines IL17a (p=0.03), Interferon-γ (p=0.0008), GCSF(p=0.0012) and MCP1(p=0.02). This change in cytokine levels from baseline to post-treatment was similar for both treatment arms except a higher increase in IL17a(p=0.015) was noted in the standard chemotherapy arm compared to the Bv arm (Table 1). Among 147 paired samples evaluated, sCD30, sCD163 and TARC all were significantly lower post treatment (Figure 1), but did not differ across arms. Pre treatment sCD163 and TARC values were significantly associated with EFS (p = 0.005 and 0.045), as was the degree of change in sCD163 post-treatment levels as compared to pre-treatment levels (p = 0.0156). Among 71 patients with pre and post ELISPOT-T cell data, there was a significant increase in the T cell responses specific to PRAME(p=0.04) post treatment and a trend for increased MAGEA4, but no association with EFS. Conclusions Treatment results in an increased T cell response to HL-specific antigen PRAME post therapy in both treatment arms suggesting that recovery post anti-HL treatment can promote tumor antigen specific T cell immunity in vivo. Further, reduction in immunosuppressive cytokines IL-13 and changes in proinflammatory cytokines Interferon-γ following treatment suggest a favorable milieu for T cell expansion. Pre-treatment levels of soluble CD163 and TARC are associated with EFS and may present a potential predictive biomarker, as well as degree of change of CD163 post treatment, irrespective of addition of immunotherapy. Our results have implications for identifying immune markers of response to guide future immunotherapies and cytotoxic T cell therapy in cHL. (NCT02166463)

Oral Chemotherapy Adherence in Pediatric Acute Lymphoblastic Leukemia (ALL): A Report from the Dana-Farber Cancer Institute (DFCI) ALL Consortium Protocol 16-001

Background: Successful treatment of pediatric acute lymphoblastic leukemia (ALL) requires 2 years of risk-directed therapy, much of which is built on a backbone of oral chemotherapy including 6-mercaptopurine (6MP) and dexamethasone (DEX). Studies conducted in the Children's Oncology Group (COG) demonstrate that poor adherence to 6MP during the maintenance phase confers increased relapse risk; however, little is known about the rates of 6MP adherence in non-COG ALL regimens. DFCI ALL Consortium protocols utilize 3-week cycles including 14-day pulses of 6MP with weekly intravenous or intramuscular methotrexate. This treatment approach requires more frequent contact between families and healthcare providers and reduces the number of oral chemotherapy agents prescribed. Whether this higher-touch regimen might reduce the frequency of non-adherence as compared to published COG data is not known. Additionally, there remains a paucity of data investigating incidence of non-adherence to DEX, 6MP, and to any medications during the first year of therapy. Methods: Oral chemotherapy adherence was prospectively evaluated as an embedded ancillary study on the DFCI ALL Consortium Protocol 16-001. Eligible participants included English-, Spanish-, or French-speaking caregivers of patients (<22 years) receiving 6MP and DEX (both liquid and tablet formations) and did not utilize a pillbox. Adherence to 6MP and DEX were measured using Medication Event Monitoring Systems (MEMS) caps, which record the date and time of medicine bottle opening. MEMS caps were used to measure adherence for three consecutive cycles during the first year of therapy, and again for three consecutive cycles during the second year of therapy. Caregivers completed surveys reporting sociodemographic determinants of health (SDOH), medication-taking behaviors, and chemotherapy comprehension. MEMS-based medication adherence rates were calculated as a percentage based upon the ratio of the number of days with MEMS cap openings to the number of days 6MP and/or DEX were prescribed. Adherent patients were defined as those with ≥95% adherence based on prior COG trials that observed an excess risk of relapse below this threshold (Bhatia JAMA Onc 2015). Results: Between 2018 - 2022, 252/429 (59%) eligible patients consented to study participation, and adherence data was successfully collected for 207 (82%). Sixty-six (26%) participants were enrolled from Canadian hospital centers, and 186 (74%) participants were enrolled from US hospital centers. Participant age included 159 (77%) <10 years of age, 31 (15%) 10 - 14 years, and 17 (8%) 15 - 21 years (see Table 1). Thirty-four (16%) patients identified as Hispanic, 13 (6%) non-Hispanic Black, 18 (9%) non-Hispanic Other, and 142 (69%) non-Hispanic White. 57 (31%) patients relied on public insurance at time of diagnosis, 61 (34%) patients reported a primary household language other than English, and 36 (20%) patients lived in lone-parent households. A third, 61 (34%) and 62 (34%), of caregivers reported being unsure of what would happen if their child stopped taking 6MP or DEX, respectively. Over the course of six cycles, MEMS-measured adherence rates to 6MP (N = 180) and DEX (N = 195) were 73% (range 21 - 100) and 86% (range 10 - 100), respectively. Preliminary data suggest that adherence rates to 6MP improved during year 2 of treatment (cycles 4-6 of monitoring) (Table 2). In unadjusted analyses, there was a non-significant association between patient age and likelihood of adherence to oral medication: adherence to 6MP was 71% in those <10 years, 80% in those 10 - 14 years, and 71% in those 15 years or older (Jonckheere-Terpstra test p = 0.66). Conclusion: Among a diverse cohort of patients treated with a DFCI ALL Consortium regimen, adherence to oral chemotherapy is suboptimal with rates of 73% to 6MP and 86% to DEX. This finding recapitulates published data from COG ALL trials, suggesting more frequent contact with healthcare providers in the DFCI Consortium protocol does not mitigate non-adherence. Numerical differences between age groups suggest patients ages 10 - 14 years (N=31) have higher adherence compared to patients both younger and older. These preliminary findings suggest that there may be a behavioral component when it comes to medication adherence - with barriers among young children differing from those in both younger and older adolescents.

Association of the social disorganization index with time to first septic shock event in children with acute myeloid leukemia.

Pediatric acute myeloid leukemia (AML) chemotherapy increases the risk of life-threatening complications, including septic shock (SS). An area-based measure of social determinants of health, the social disorganization index (SDI), was hypothesized to be associated with SS and SS-associated death (SS-death). Children treated for de novo AML on two Children's Oncology Group trials at institutions contributing to the Pediatric Health Information System (PHIS) database were included. The SDI was calculated via residential zip code data from the US Census Bureau. SS was identified via PHIS resource utilization codes. SS-death was defined as death within 2weeks of an antecedent SS event. Patients were followed from 7days after the start of chemotherapy until the first of end of front-line therapy, death, relapse, or removal from study. Multivariable-adjusted Cox regressions estimated hazard ratios (HRs) comparing time to first SS by SDI group. The assembled cohort included 700 patients, with 207 (29.6%) sustaining at least one SS event. There were 233 (33%) in the SDI-5 group (highest disorganization). Adjusted time to incident SS did not statistically significantly differ by SDI (reference,SDI-1; SDI-2: HR, 0.84 [95% confidence interval (CI), 0.51-1.41]; SDI-3: HR, 0.70 [95% CI, 0.42-1.16]; SDI-4: HR, 0.97 [95% CI, 0.61-1.53]; SDI-5: HR, 0.72 [95% CI, 0.45-1.14]). Nine patients (4.4%) with SS experienced SS-death; seven of these patients (78%) were in SDI-4 or SDI-5. In a large, nationally representative cohort of trial-enrolled pediatric patients with AML, there was no significant association between the SDI and time to SS.

Outcomes in Children, Adolescents, and Young Adults With Down Syndrome and ALL: A Report From the Children's Oncology Group.

Patients with Down syndrome (DS) and B-ALL experience increased rates of relapse, toxicity, and death. We report results for patients with DS B-ALL enrolled on Children's Oncology Group trials between 2003 and 2019. We analyzed data for DS (n = 743) and non-DS (n = 20,067) patients age 1-30 years on four B-ALL standard-risk (SR) and high-risk trials. Patients with DS exhibited more frequent minimal residual disease (MRD) ≥0.01% at end induction (30.8% v 21.5%; P < .001). This difference persisted at end consolidation only in National Cancer Institute (NCI) high-risk patients (34.0% v 11.7%; P < .0001). Five-year event-free survival (EFS) and overall survival (OS) were significantly poorer for DS versus non-DS patients overall (EFS, 79.2% ± 1.6% v 87.5% ± 0.3%; P < .0001; OS, 86.8% ± 1.4% v 93.6% ± 0.2%; P < .0001), and within NCI SR and high-risk subgroups. Multivariable Cox regression analysis of the DS cohort for risk factors associated with inferior EFS identified age >10 years, white blood count >50 × 103/μL, and end-induction MRD ≥0.01%, but not cytogenetics or CRLF2 overexpression. Patients with DS demonstrated higher 5-year cumulative incidence of relapse (11.5% ± 1.2% v 9.1% ± 0.2%; P = .0008), death in remission (4.9% ± 0.8% v 1.7% ± 0.1%; P < .0001), and induction death (3.4% v 0.8%; P < .0001). Mucositis, infections, and hyperglycemia were significantly more frequent in all patients with DS, while seizures were more frequent in patients with DS on high-risk trials (4.1% v 1.8%; P = .005). Patients with DS-ALL exhibit an increased rate of relapse and particularly of treatment-related mortality. Novel, less-toxic therapeutic strategies are needed to improve outcomes.

Children's Oncology Group's 2023 blueprint for research: Diversity and health disparities.

The Children's Oncology Group (COG) Diversity and Health Disparities Committee's (DHDC's) mission is to guarantee the highest standard of care for children and adolescents and young adults (AYA) with cancer regardless of ethnic, racial, gender, or socioeconomic background. We strive to identify and address issues of disparity within the existing scientific structure of COG and to support research across COG to improve survival by ensuring equitable access to COG-sponsored clinical trials. We are committed to advance COG-led research identifying mechanistic drivers of disparities and, concurrently, evaluating interventions to alleviate disparities in the COG trial setting. As trials identify the most promising therapies, diverse representation is critical to ensure that findings are relevant to everyone. Factors impacting clinical trial participation among vulnerable populations are complex, consisting of barriers at societal, systems, and individual levels. Recent efforts by investigators within DHDC demonstrated that trial-embedded collection of family-reported sociodemographic data and social determinants of health (SDoH) is feasible and acceptable in the context of COG. Diversity in the pediatric oncology workforce is essential and one potential approach to improving representation on clinical trials. To support and retain diverse oncology providers and researchers, a Minority Young Investigator Award (MYIA) was created to facilitate opportunities for graduating trainees and YIs with an interest in childhood cancer disparities research within COG. Although there are challenges to achieve the DHDC's priorities, only through collaboration and support for this work we will be able to elucidate mechanisms underlying inferior survival outcomes for historically marginalized children and AYA, and more importantly, implement interventional investigation to improve outcomes.

Children's Oncology Group blueprint for research: Acute lymphoblastic leukemia.

Cure rates for acute lymphoblastic leukemia (ALL), the most common childhood cancer have steadily improved over the past five decades. This is due to intensifying systemic therapy, recognizing and treating the central nervous system as a sanctuary site, and implementing modern risk stratification to deliver varying intensities of therapy based on age, presenting white blood count, sentinel somatic genetics, and therapy response. Recently, numerous Children's Oncology Group trials have demonstrated the lack of benefit of intensifying traditional chemotherapy, providing evidence that new approaches are needed to cure the patients for whom cure has been elusive. Distinguishing those who require intensive or novel therapeutic approaches from others who will be cured with minimal therapy is key for future trials. Incorporating new genomic biomarkers and more sensitive measures of minimal/measurable residual disease provide opportunities to achieve these goals.

Children's Oncology Group 2023 blueprint: Nursing discipline.

In contrast to other Children's Oncology Group (COG) committees, the COG nursing discipline is unique in that it provides the infrastructure necessary for nurses to support COG clinical trials and implements a research agenda aimed at scientific discovery. This hybrid focus of the discipline reflects the varied roles and expertise within pediatric oncology clinical trials nursing that encompass clinical care, leadership, and research. Nurses are broadly represented across COG disease, domain, and administrative committees, and are assigned to all clinically focused protocols. Equally important is the provision of clinical trials-specific education and training for nurses caring for patients on COG trials. Nurses involved in the discipline's evidence-based practice initiative have published a wide array of systematic reviews on topics of clinical importance to the discipline. Nurses also develop and lead research studies within COG, including stand-alone studies and aims embedded in disease/ treatment trials. Additionally, the nursing discipline is charged with responsibility for developing patient/family educational resources within COG. Looking to the future, the nursing discipline will continue to support COG clinical trials through a multifaceted approach, with a particular focus on patient-reported outcomes and health equity/disparities, and development of interventions to better understand and address illness-related distress in children with cancer.

Feasibility and acceptability of social determinants of health data collection in the context of a Children’s Oncology Group trial.

10010 Background: Children who are Black, Hispanic or of proxied low socioeconomic status experience inferior survival outcomes despite receipt of uniform treatment on Children’s Oncology Group (COG) trials. Investigation of mechanisms underlying these disparities and evaluation of interventions to address them has been limited by inadequate data. Prior COG trials have collected child race, ethnicity, insurance and zip code—non-modifiable data elements that are prone to misclassification bias—as proxies for exposure to adverse social determinants of health (SDOH). Collection of parent-reported SDOH data provides key information not previously assessed in COG trials, including modifiable exposures such as household material hardship (HMH): food, housing, utility or transportation insecurity. We report the preliminary feasibility and acceptability of the first COG trial to prospectively embed SDOH data collection. Methods: ANBL1531 (NCT03126916), the current frontline, groupwide COG trial for patients with high-risk neuroblastoma, was amended in September 2019 to include an opt-in, correlative aim to evaluate parent-reported SDOH. Parents of patients &lt; 18 years could opt-in during initial ANBL1531 consent to complete a brief, single-timepoint survey at their enrolling site during Induction Cycle 1. Survey domains included parent-reported demographics, HMH, household income, and social support. Paper/pencil surveys available in English, Spanish or French were self-completed or read-aloud by site personnel and could be administered in any language with an interpreter. Surveys were submitted to a central disparities study team for data cleaning and entry into an electronic database. Results: As of December 31, 2022, 360/413 eligible participants opted-in to the embedded SDOH aim across 101 COG sites (87.2% consent rate). Among participants, 316 surveys (87.8%) were completed a median of 11 days post-enrollment. Four (1.1%) parents declined survey completion (3 withdrew consent). Reasons for non-completed surveys included: survey still pending within protocol-specified window (n = 10), institutional COVID-19 restrictions (n = 6), site scheduling issues (n = 6), patient came off ANBL1531 protocol (n = 5) and unknown (n = 13). Data missingness for HMH, the primary SDOH of interest, was 0.8%. Surveys were administered in English, Spanish, French, Vietnamese, Arabic, Mandarin and Tamil. Conclusions: Collection of parent-reported SDOH data as an optional, embedded component of a groupwide COG trial is feasible and acceptable, as demonstrated by remarkable willingness to participate and infrequency of missing data. Incorporation of this approach in future National Clinical Trials Network trials is essential to inform impactful health equity research, including the development and evaluation of targeted interventions to address outcome disparities.

Impact of race and ethnicity on presentation and outcomes of patients treated on rhabdomyosarcoma clinical trials: A report from the Children's Oncology Group.

Racial and ethnic disparities have been demonstrated in pediatric and adult cancers. However, there is no consensus on whether such disparities exist in the presentation, treatment, and outcome of patients with rhabdomyosarcoma (RMS). Patient information from the seven most recent RMS clinical trials was obtained from the Children's Oncology Group (COG). Chi-squared analyses were used to compare patient, tumor, and treatment characteristics across racial and ethnic groups. Pairwise analyses comparing Non-Hispanic Black (NHB) versus Non-Hispanic White (NHW) racial groups and Hispanic versus NHW ethnic groups were conducted for significant characteristics. Kaplan-Meier method and Wilcoxon signed-rank tests were performed to analyze outcomes. In the overall cohort (n = 2157), patients'self-identified race/ethnicity was: 0.4% American Indian/Alaska Native, 2.6% Asian, 12.6% Hispanic, 0.2% Native American/other Pacific Islander, 12.8% NHB, 61.9% NHW, and 9.6% unknown. Six characteristics differed by race/ethnicity: age, histology, IRS group, invasiveness, metastatic disease, and FOXO1 fusion partner. Five were significant in pairwise comparisons: NHB patients were more likely to present at age ≥ 10 years and with invasive tumors than NHW patients; Hispanic patients were more likely to present with alveolar histology, metastatic disease, and IRS group IV disease than NHW patients. No differences were found in event free or overall survival of the entire cohort, in risk group-based subset analyses, or among patients with high-risk characteristics significant on pairwise analysis. While NHB and Hispanic patients enrolled in COG trials presented with higher risk features than NHW patients, there were no outcome differences by racial or ethnic group.

Survival of patients with orbital and eyelid rhabdomyosarcoma treated on Children's Oncology Group studies from 1997 to 2013: A report from the Children's Oncology Group.

Orbital rhabdomyosarcoma (ORMS) commonly presents as low-risk disease (stage 1, group I-III, embryonal RMS) with excellent outcome. Long-term follow-up of patients with low-risk ORMS and outcomes of less common subgroups of ORMS treated on recent Children's Oncology Group (COG) trials have not been reported. Patients with ORMS enrolled on COG trials from 1997 to 2013 were identified. Demographic information and disease characteristics were collected. Outcomes were determined for the following subgroups: 1) low-risk ORMS, 2) resected (group I/II) low-risk ORMS, 3) non-low-risk ORMS, and 4) recurrent ORMS. Event-free survival (EFS) and overall survival (OS) were estimated using the Kaplan-Meier method. ResultsThe authors identified 218 patients with ORMS. Most tumors were embryonal/botryoid (n=169; 77.5%), <5cm (n=213; 97.7%), group III (n=170; 78.0%), and without lymph node involvement (N0; n=215; 98.6%). For 192 patients with low-risk ORMS, the 10-year EFS and OS rates were 85.5% (95% confidence interval [CI], 77.0%-94.0%) and 95.6% (95% CI, 90.8%-100.0%), respectively. Those with group I/II low-risk ORMS (n = 5 in group I; n = 39 in group IIA) had 10-year EFS and OS rates of 88.0% (95% CI, 72.6%-100.0%) and 97.6% (95% CI, 90.0%-100.0%), respectively. Twenty-six patients with non-low-risk ORMS had 5-year EFS and OS rates of 88.5% (95% CI, 75.6%-100.0%) and 95.8% (95% CI, 87.7%-100.0%), respectively. For patients with recurrent ORMS, the 10-year OS rate from the time of recurrence was 69.4% (95% CI, 50.0%-88.8%). Patients with ORMS had favorable long-term survival outcomes on COG studies from 1997 to 2013, including those who had both low-risk and non-low-risk disease. A significant proportion of patients with recurrent ORMS may achieve long-term survival.

Trends in Pediatric Cancer Care in Florida From 1981-2020: Changing Patterns in a Growing and Increasingly Diverse Population.

Background The Florida Association of Pediatric Tumor Programs (FAPTP) has used the Statewide Patient Information Reporting System (SPIRS) since 1981 to track all new cases of pediatric cancer. We reviewed the last 40 years of data to see how pediatric cancer care has evolved. Methods We retrospectively analyzed SPIRS data from 1981 through 2020 in five-year increments, looking at numbers of new diagnoses, care delivery sites, and trial enrollment in Children's Oncology Group (COG) studies. Results From 1981-2020 Florida's population increased almost 88% while the pediatric population only grew 61%.New pediatric cancer diagnoses increased 326% to over 1,000 new cases/year. The percentage of patients treated at FAPTP centers grew from 30% to 57% with an annual percentage change (APC) of 10.3% (95% Confidence Interval [CI] of 0.6 to 20.9%). The rate of COG clinical trial enrollment decreased from 32% in 1981-1985 to 20% in 2016-2020, for an APC of 8.91% (95% CI of -13.3 to -4.3%). Conclusions The striking increase in pediatric cancer cases in Florida over the last 40 years was out of proportion to the population growth. More patients received care at FAPTP centers, but a lower percentage were enrolled on COG trials.

Pathologic, cytogenetic, and molecular features of acute myeloid leukemia with megakaryocytic differentiation: A report from the Children's Oncology Group.

Acute myeloid leukemia (AML) with megakaryocytic differentiation (AMkL) is a rare subtype of AML more common in children. Recent literature has identified multiple fusions associated with this type of leukemia. Morphology, cytogenetics, and genomic sequencing were assessed in patients from Children's Oncology Group trials AAML0531 and AAML1031 with central-pathology review confirmed non-Down syndrome AMkL. The 5-year event-free survival (EFS), overall survival (OS), and RR were evaluated in these AMkL subcategories. A total of 107 cases of AMkL (5.5%) were included. Distinct fusions were identified in the majority: RBM15::MRTFA (20%), CBFA2T3::GLIS2 (16%), NUP98 (10%), KMT2A (7%), TEC::MLLT10 (2%), MECOM (1%), and FUS::ERG (1%); many of the remaining cases were classified as AMkL with (other) myelodysplasia-related changes (MRC). Very few cases had AML-associated somatic mutations. Cases with CBFA2T3::GLIS2 were enriched in trisomy 3 (p=.015) and the RAM phenotype, with associated high CD56 expression (p<.001). Cases with NUP98 fusions were enriched in trisomy 6 (p<.001), monosomy 13/del(13q) (p<.001), trisomy 21 (p=.026), and/or complex karyotypes (p=.026). While different 5-year EFS and OS were observed in AMkL in each trial, in general, those with CBFA2T3::GLIS2 or KMT2A rearrangements had worse outcomes compared to other AMkL, while those with RBM15::MRTFA or classified as AMkl-MRC fared better. AMkL with NUP98 fusions also had poor outcomes in the AAML1031 trial. Given the differences in outcomes, AMkL classification by fusions, cytogenetics, and morphology may be warranted to help in risk stratification and therapeutic options.

Racial and ethnic disparities in childhood and young adult acute lymphocytic leukaemia: secondary analyses of eight Children's Oncology Group cohort trials

Previous studies have identified racial and ethnic disparities in childhood acute lymphocytic leukaemia survival. We aimed to establish whether disparities persist in contemporaneous cohorts and, if present, are attributable to differences in leukaemia biology or insurance status. Patients with newly diagnosed acute lymphocytic leukaemia in inpatient and outpatient centres in the USA, Canada, Australia, and New Zealand, aged 0-30 years, who had race or ethnicity data available, enrolled on eight completed Children's Oncology Group trials (NCT00103285, NCT00075725, NCT00408005, NCT01190930, NCT02883049, NCT02112916, NCT02828358, and NCT00557193) were included in this secondary analysis. Race and ethnicity were categorised as non-Hispanic White, Hispanic, non-Hispanic Black, non-Hispanic Asian, and non-Hispanic other. Event-free survival and overall survival were compared across race and ethnicity groups. The relative contribution of clinical and biological disease prognosticators and insurance status was examined through multivariable regression models, both among the entire cohort and among those with B-cell lineage versus T-cell lineage disease. Between Jan 1, 2004, and Dec 31, 2019, 24 979 eligible children, adolescents, and young adults with acute lymphocytic leukaemia were enrolled, of which 21 152 had race or ethnicity data available. 11 849 (56·0%) were male and 9303 (44·0%) were female. Non-Hispanic White patients comprised the largest racial or ethnic group (13 872 [65·6%]), followed by Hispanic patients (4354 [20·6%]), non-Hispanic Black patients (1517 [7·2%]), non-Hispanic Asian (n=1071 [5·1%]), and non-Hispanic other (n=338 [1·6%]). 5-year event-free survival was 87·4% (95% CI 86·7-88·0%) among non-Hispanic White patients compared with 82·8% (81·4-84·1%; hazard ratio [HR] 1·37, 95% CI 1·26-1·49; p<0·0001) among Hispanic patients and 81·8% (79·3-84·0; HR 1·45, 1·28-1·65; p<0·0001) among non-Hispanic Black patients. Non-hispanic Asian patients had a 5-year event-free survival of 88·1% (95% CI 85·5-90·3%) and non-Hispanic other patients had a survival of 82·8% (76·4-87·6%). Inferior event-free survival among Hispanic patients was substantially attenuated by disease prognosticators and insurance status (HR decreased from 1·37 [1·26-1·49; p<0·0001] to 1·11 [1·00-1·22; p=0·045]). The increased risk among non-Hispanic Black patients was minimally attenuated (HR 1·45 [1·28-1·65; p<0·0001] to 1·32 [1·14-1·52; p<0·0001]). 5-year overall survival was 93·6% (91·5-95·1%) in non-Hispanic Asian patients, 93·3% (92·8-93·7%) in non-Hispanic White patients, 89·9% (88·7-90·9%) in Hispanic, 89·7% (87·6-91·4%) in non-Hispanic Black patients, 88·9% (83·2-92·7%) in non-Hispanic other patients. Disparities in overall survival were wider than event-free survival (eg, among non-Hispanic other patients, the HR for event-free survival was 1·43 [1·10-1·85] compared with 1·74 [1·27-2·40] for overall survival). Disparities were restricted to patients with B-cell acute lymphocytic leukaemia, no differences in event-free survival or overall survival were seen in the T-cell acute lymphocytic leukaemia group. Substantial disparities in outcome for B-cell acute lymphocytic leukaemia persist by race and ethnicity, but are not observed in T-cell acute lymphocytic leukaemia. Future studies of relapsed patients, access to and quality of care, and other potential aspects of structural racism are warranted to inform interventions aimed at dismantling racial and ethnic disparities. National Cancer Institute and St Baldrick's Foundation.

Crizotinib in Combination With Chemotherapy for Pediatric Patients With ALK+ Anaplastic Large-Cell Lymphoma: The Results of Children's Oncology Group Trial ANHL12P1.

Arm crizotinib (CZ) of the Children's Oncology Group trial ANHL12P1 (ClinicalTrials.gov identifier: NCT01979536) examined the efficacy and toxicity of adding CZ to standard chemotherapy for children with newly diagnosed, nonlocalized ALK+ CD30+ anaplastic large-cell lymphoma (ALCL). Between 2013 and 2019, 66 enrolled children received CZ with chemotherapy. Patients received a 5-day prophase followed by six chemotherapy cycles at 21-day intervals with CZ administered twice daily during each 21-day cycle. The study was temporarily closed for two periods (total 12 months) to evaluate toxicity, during which CZ was discontinued. Measurements of NPM-ALK fusion transcripts in peripheral blood were performed at diagnosis for minimal disseminated disease (MDD). The 2-year event-free survival (EFS) is 76.8% (95% CI, 68.5 to 88.1) and the 2-year overall survival is 95.2% (95% CI, 85.7 to 98.4). Fifteen patients relapsed and one patient died; median time to relapse was 7.4 months from diagnosis, with relapses occurring after chemotherapy was complete. The 66 patients completed 384 cycles of chemotherapy. Thirteen of the 66 patients experienced a grade 2+ thromboembolic adverse event (19.7%; 95% CI, 11.1 to 31.3). In the 25 patients who received mandated prophylactic anticoagulation, there were two thromboembolic events (8.0%; 95% CI, 0.01 to 26). Patients with negative MDD had a superior outcome, with an EFS of 85.6% (95% CI, 68.6 to 93.8); positive MDD was associated with a lower EFS of 58.1% (95% CI, 33.4 to 76.4). Arm CZ of ANHL12P1 demonstrated that the addition of CZ to standard treatment prevented relapses during therapy for children with ALCL, MDD predicted EFS, and the addition of CZ resulted in unexpected thromboembolic events. Overall survival and EFS rates are consistent with the highest reported outcomes for children with ALCL.

High Immunoproteasome Expression As Indicator for Sensitivity to Bortezomib-Containing Chemotherapy in Newly Diagnosed, Standard and Intermediate Risk, T-Cell Acute Lymphoblastic Leukemia Patients from Children's Oncology Group Trial AALL1231

Background: Proteasome inhibition by bortezomib (BTZ) has previously been shown to be beneficial for a subset of patients with relapsed/refractory acute leukemia. Several (pre)clinical studies showed that relatively high immunoproteasome expression (β1i and β5i) may serve as a biomarker for BTZ-sensitivity and aid to select patients that may respond well to BTZ-containing therapy (Cloos J et al. Cancer Metastasis Rev. 2017). In this study we investigated whether we could confirm these findings in newly diagnosed T-cell acute lymphoblastic leukemia patients (T-ALL) enrolled in the COG-AALL1231 phase 3 clinical trial (Teachey DT et al. J Clin Oncol 2022). In that trial, patients in treatment arm A received augmented Berlin-Frankfurt-Münster (aBFM) therapy, while for those in treatment arm B, BTZ was added to the aBFM regimen. Methods: Baseline immuno- and constitutive proteasome subunit expression was determined in bone marrow samples of 77 standard and intermediate risk T-ALL patients using Western blot. To correct for potential variation between blots, two cell lines were included as internal quantification controls, i.e. the human (BTZ-sensitive) T-ALL cell line CCRF-CEM (CEM-WT) and its subline (CEM-BTZ200) with acquired resistance to 200 nM BTZ. Protein bands were quantified and calculated relative to β-actin and the subunit expression of CEM-WT. Mann-Whitney U and log-rank tests were used for between group comparisons of proteasome subunit expressions and event free survival (EFS), respectively. Induction failure, relapse and death (induction and remission) were considered as EFS events. Results: In the bone marrow samples, a very strong correlation was observed between immunoproteasome β5i and β1i subunit expression (R=0.9, P<0.0001, Figure 1A). The correlation for constitutive subunits was R=0.7, P<0.0001. Interestingly, females had significantly higher β1i and β5i immunoproteasome levels compared to males with medians of 5.1 (range: 0.9-18.7) and 1.6 (0.3-17.9) respectively for the β1i subunit (P =0.05), and medians of 4.8 (1.9-16.1) and 1.8 (0.6-10.8) respectively for the β5i subunit (P =0.0084). Three year EFS was used as a measure for response to therapy. In patients treated with the BTZ-containing therapy (arm B), higher immunoproteasome expression levels (>0.8, based on Max-stat analysis) correlated with an improved EFS (P=0.034 for β1i and P=0.011 for β5i, Figure 1B). In contrast, in treatment arm A, higher immunoproteasome expression levels were associated with a relatively poor EFS, although this difference was not statistically significant likely due to low patient numbers in the low immunoproteasome subunit expression group in arm A (β1i N=5 and β5i N=1, for arm B β1i N=6 and β5i N=4). No other factors, including age, ethnicity, and gender, were found to be significantly associated with EFS. Discussion: These results support our hypothesis that patients with higher immunoproteasome expression levels are responsive to proteasome inhibitors such as BTZ, with better EFS after BTZ-containing therapy. When comparing the patients with high immunoproteasome expression of arm A versus arm B, the latter displays a better EFS (3 years EFS 96% for arm B vs 80% for arm A, P=0.08). Although not statistically significant, this factor may be indicative of a beneficial effect of BTZ-treatment in this subgroup of patients. The limitation of this study is the relatively low number of samples in each subgroup, in particular the patients with low expression of immunoproteasome subunits. Since most patients show a high level of immunoproteasome, only the few with low expression might not benefit from BTZ treatment and may be allocated for alternative strategies. The relevance of the immunoproteasome for BTZ sensitivity in these samples will be further examined by proteasome subunit catalytic activity measurements with subunit-specific substrates and other known factors contribution to diminished BTZ sensitivity (Niewerth et al. Drug Resist Updates 2015). Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Improved Relapse Prediction in Pediatric Acute Myeloid Leukemia By Deconvolving Lineage-Specific and Cancer-Specific Features in Single-Cell Data

Introduction While most children with acute myeloid leukemia (AML) achieve first remission, nearly 40% will relapse. Of these children, few survive to a second remission even with highly-escalated treatment protocols. Recent studies have shown that many AML patients harbor rare, stem cell-like subpopulations that resist chemotherapy and drive relapse. However, the exact characteristics of these relapse-associated cells are a matter of contention, with reported phenotypes spanning the hematopoietic developmental continuum. In some patients, treatment-resistant cells can be detected as minimal residual disease (MRD), which is often used to predict relapse, albeit with limited accuracy and only after induction chemotherapy. Thus, the identity of treatment-resistant cells as well as their relationship to normal progenitors remain mysterious, thereby limiting the development of targeted therapies for pediatric AML. Here, we present a computational approach for decomposing high-dimensional single-cell measurements into two components: a lineage-specific component that can be used to align cancer cells with specific stages of myeloid development and a cancer-specific component that can be used to identify aberrant phenotypes unique to AML cells. We show that, together, these components can be used at the time of diagnosis to predict relapse more accurately than clinical information alone. Methods and Results Using mass cytometry, we analyzed paired diagnostic and post-induction samples collected from 19 (8 relapse, 11 non-relapse) pediatric patients who enrolled on the Children's Oncology Group trial AAML1031. All patients were treated on the control arm and consented to banking of tissue for research. We also included 5 bone marrow samples from healthy donors. After thawing, samples were divided in half and stimulated with conditioned medium from the human bone marrow stromal cell line HS-5 to activate relevant signaling pathways, or left unstimulated. An average of 5 x 105 cells per patient were analyzed for each condition. The mass cytometry panel included 31 antibodies to surface markers, 6 antibodies to intracellular signaling mediators, and 4 antibodies to intracellular proteins and transcription factors. Following data collection, the singular value decomposition was applied to the data matrix of healthy single-cell measurements to construct a linear subspace representing the predominant protein expression programs ("eigencells") within the healthy myeloid developmental continuum. By projecting AML single-cell measurements onto this subspace, we derived a healthy feature vector aligned with the healthy subspace and a cancer-specific feature vector orthogonal to the healthy subspace for each AML cell. These feature vectors-along with clinical metadata about each patient including age, blast percentage at diagnosis, and cytogenetic status-were used as the input to regularized Cox proportional hazards models predicting time-to-relapse for each patient. Using the relative risk scores from the proportional hazards model, patients were assigned to high-risk or low-risk groups according to the optimal log-rank test threshold. The baseline clinical model used only age, blast percentage at diagnosis, and cytogenetic status as predictors and predicted relapse status with an accuracy of 13/19 (68%). This baseline model was outperformed by the model constructed using the average value of the single-cell cancer-specific feature vectors for each patient, which predicted relapse status with an accuracy of 16/19 (84%). Interestingly, despite using only information available at diagnosis, the single-cell model also outperformed a clinical model incorporating patients' MRD status after induction chemotherapy, which predicted relapse with an accuracy of 15/19 (79%). Interrogation of the coefficients of the single-cell feature model revealed specific cellular signaling programs associated with relapse, including enhanced pCreb and pSTAT1 signaling as well as depleted pSTAT5 signaling relative to healthy lineage cells (Figure 1). Conclusions These results support the feasibility of predicting relapse in AML as early as diagnosis by leveraging a computational approach that compares cancer cells to the native lineage from which they arise. Validation of this approach in an independent cohort is ongoing and will be presented. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

The Influence of Genetic Ancestry on Disease Biology in Pediatric T-Cell Acute Lymphoblastic Leukemia

Introduction: Pediatric T-cell Acute Lymphoblastic Leukemia (T-ALL) is a biologically heterogenous disease that can be grouped into 16 subtypes based on integration of gene expression and somatic genomic alterations that have variable prevalence of activated targetable pathways (Pölönen P., et al ASH 2022). In both adult cancers and pediatric B-cell ALL, genetic ancestry has been associated with tumor biology and clinical outcomes; however, there is a paucity of data exploring the influence of genetic ancestry in T-ALL. Thus, we sought to determine the association of genetic ancestry with tumor biology in pediatric T-ALL. Methods: Whole genome sequencing (germline and tumor) and bulk RNA-sequencing was performed to characterize T-ALL subtype and pathway aberrations among 1312 newly diagnosed T-ALL patients treated on Children's Oncology Group trial AALL0434. Genetic ancestral composition was determined for each individual using the iAdmix program comparing allele frequencies between patients and reference genomes from the 1000 Genomes Project. Coefficients from the 5 reference populations (European (EUR), African (AFR), East Asian (EAS), South Asian (SAS), and American Admixture (AA)) were assumed to sum to 100%. Categorical genetic ancestral groups were classified from prior methods: "European" (EUR >90%), "African" (AFR >70%), "East Asian" (EAS >90%), "South Asian" (SAS >70%), and "Amerindian" (AA >10% and AA greater than AFR), with the rest defined as "Other." We evaluated associations of genetic ancestry with T-ALL molecular subtypes and pathways. Ancestry was first examined as a categorical variable using Fisher's exact test for its association with subtypes and pathways. Ancestry was also analyzed as a continuous variable using logistic regression for association with pathways and multinomial regression for association with subtype (TAL1-RB subtype as reference). The effect of ancestry was summarized as odds ratios (OR) for every 25% increase in a non-European ancestry, with a concurrent 25% decrease in European ancestry and remaining ancestries fixed. Results: Categorical ancestral composition in this cohort was 59% European, 11% African, 15% Amerindian, 3% East Asian, 2% South Asian, 10% Other. The prevalence of T-ALL subtypes differed by genetic ancestry (Figure 1). For example, HOXA9 and BCL11B, which are linked to ETP T-ALL, were significantly enriched in children of African genetic ancestry as compared to European ancestry (HOXA9: 11% AFR vs. 6% EUR; BCL11B: 3% AFR vs. 1.5% EUR). ETP phenotype was also more common in children of African descent as compared with European (11.9% vs. 7.5%, p =0.031). In analyses of ancestry as a continuous variable (with European as the reference), four subtypes and four pathways exhibited differences in odds of expression (Table 1). For every 25% increase in African ancestry, the odds of BCL11B subtype was 41% higher (p=0.034), odds of HOXA9 subtype was 26% higher (p=0.020), odds of MLLT10_TRA was 68% higher (p<0.001), and odds of tumor microenvironment (TME) aberrant subtype was 33% higher (p=0.027). For every 25% increase in African ancestry, patients were also 1.13-fold more likely to harbor JAK/STAT mutations (p=0.049) and 1.18-fold for MAPK/RAS pathway alterations (p=0.011), with decreasing odds of NOTCH mutations (OR=0.88, p=0.014) or ribosomal gene alterations (OR=0.69, p=0.003). For increasing East Asian ancestry, patients were also less likely to have NOTCH pathway alteration (OR=0.85, p=0.027), whereas there was no difference for increasing South Asian ancestry. Conclusion: Disease biology varies substantially among children of different genetic ancestries with T-ALL. Given that subtypes may inform future risk stratification, and pathways may guide novel treatment strategies, examining subtype and pathway expression for children of all ancestral backgrounds is critical. Important biological indicators of risk may be missed when studying patients of a single genetic ancestral group or when focusing on averages for the entire cohort without taking into consideration variation in genetic ancestry. Analyses of survival by genetic ancestry within genomic groups are ongoing. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal