Chemotherapy and Supportive Care Agents as Essential Medicines for Children With Cancer

In resource-rich countries, 5-year survival rates for children with cancer approach 85%. This impressive statistic is largely the result of integrating research with clinical care. At the core of this endeavor are multiagent combination chemotherapy and supportive care agents (CASCA). Most CASCAs belong to the class of sterile injectable drugs, which make up the backbone of many proven and life-saving pediatric oncology regimens. There are few if any alternative agents available to treat most life-threatening childhood cancers. In the United States, shortages of CASCAs are now commonplace. The consequences of drug shortages are far reaching. Beyond the economic costs, these shortages directly affect patients' lives, and this is especially true for children with cancer. Drug shortages in general and shortages of CASCAs specifically result in increased medication errors, delayed administration of life-saving therapy, inferior outcomes, and patient deaths. One way to mitigate drug shortages is to adopt an essential medicines list and ensure that these medications remain in adequate supply at all times. We argue for creation of a CASCA-specific essential medicines list for childhood cancer and provide ethical and policy-based reasoning for this approach. We recognize that such a call has implications beyond pediatric cancer, in that children with other serious disease should have an equal claim to access to guaranteed evidence-based medicines. We provide these arguments as an example of what should be claimed for medical indications that are deemed essential to preserve life and function.

Abstract CT054: A dose escalation and toxicity study using pre-determined target concentration of Ramucirumab, a novel anti-angiogenic agent in children with recurrent / refractory solid tumors: A report from the children's oncology group phase I/ pilot consortium (ADVL1416)

Ramucirumab (RAM) is a high affinity, humanized, monoclonal antibody that binds to the extra-cellular domain of the vascular endothelial growth factor receptor (VEGFR). RAM prevents the binding of VEGF ligands with VEGFR-2, the most potent receptor of the VEGF tumor angiogenesis pathway. RAM is FDA approved for adults with NSCLC, as well as for gastric and colorectal adenocarcinoma where higher exposure was associated with better outcomes. Based on population pharmacokinetic (PK) analysis of the adult data, a minimum steady state concentration (Cmin ss) of ≥ 50 µg/ml of RAM was considered the target concentration for pediatrics. The Children's Oncology Group (COG) conducted a phase 1 study using a rolling six design to define the maximum tolerated dose (MTD) and /or a recommended phase 2 dose (RP2D), evaluate toxicities and explore circulating angiogenic cells as a biomarker for RAM monotherapy in children with recurrent/refractory solid tumors. The starting dose of 8 mg/kg IV q2 weeks (DL1) was chosen based on the adult safety profile and effective Cmin ss. Since adult data suggested that lower body weight was associated with lower Cmin ss, dose escalation to 12 mg/kg IV q2 weeks (DL2) was planned provided the MTD was not exceeded in DL1 and up to 16 mg/kg IV q2 weeks (DL3) if Cmin ss was < 50 µg/ml in 1 of 6 subjects on DL2 without exceeding the MTD. An expansion cohort was planned at the lowest dose where at least 5 of 6 subjects exceeded the target in order to generate PK data in at least 6 additional subjects < 12 years of age. In the absence of an MTD, the RP2D was defined as the dose achieving Cmin ss ≥ 50 µg/ml on day 42 ± 2, after 3 doses of RAM administered IV every 2 weeks, in at least 10 of 12 subjects. Sixteen subjects (15 eligible; 7 females), median age of 14 years (3-21 yrs.) have been enrolled. Of the 7 subjects on DL1, two had insufficient PK sampling to establish Cmin ss, including 1 who experienced grade 2 proteinuria (DLT). In the remaining 5, the median (range) Cmin ss was 66 (40-136) µg/ml; 2/5 did not achieve the target of ≥ 50 µg/ml. Of the 8 subjects on DL2, two had insufficient PK sampling, including 1 with grade 2 proteinuria (DLT). In the remaining 6, the median (range) Cmin ss was 64 (51-101) µg/ml, all ≥ 50 µg/ml; thus 12mg/kg IV q2 weeks was identified for the expansion cohort. The most common RAM related non-DLT toxicities were grade 1/2 headache in 6 subjects, grade 1/2 elevation in aspartate aminotransferase in 7 subjects and grade 2/3 hypertension in 2 subjects. Due to low participation, circulating angiogenic cells could not be analyzed. This is the first COG study in which dose escalation and RP2D for a targeted agent incorporated a primary PK endpoint (Cmin ss) based upon efficacy data from adult studies and paves the way for similar study design for future phase-1 studies.

Citation Format: Kamnesh Pradhan, Stacey L. Berg, Xiaowei Liu, Charles G. Minard, James Croop, Joel M. Reid, Elizabeth Fox, Brenda J. Weigel. A dose escalation and toxicity study using pre-determined target concentration of Ramucirumab, a novel anti-angiogenic agent in children with recurrent / refractory solid tumors: A report from the children's oncology group phase I/ pilot consortium (ADVL1416) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT054.

Integrated tumor and germline whole-exome sequencing identifies mutations in MAPK and PI3K pathway genes in an adolescent with rosette-forming glioneuronal tumor of the fourth ventricle

The integration of genome-scale studies such as whole-exome sequencing (WES) into the clinical care of children with cancer has the potential to provide insight into the genetic basis of an individual's cancer with implications for clinical management. This report describes the results of clinical tumor and germline WES for a patient with a rare tumor diagnosis, rosette-forming glioneuronal tumor of the fourth ventricle (RGNT). Three pathogenic gene alterations with implications for clinical care were identified: somatic activating hotspot mutations in FGFR1 (p.N546K) and PIK3CA (p.H1047R) and a germline pathogenic variant in PTPN11 (p.N308S) diagnostic for Noonan syndrome. The molecular landscape of RGNT is not well-described, but these data are consistent with prior observations regarding the importance of the interconnected MAPK and PI3K/AKT/mTOR signaling pathways in this rare tumor. The co-occurrence of FGFR1, PIK3CA, and PTPN11 alterations provides further evidence for consideration of RGNT as a distinct molecular entity from pediatric low-grade gliomas and suggests potential therapeutic strategies for this patient in the event of tumor recurrence as novel agents targeting these pathways enter pediatric clinical trials. Although RGNT has not been definitively linked with cancer predisposition syndromes, two prior cases have been reported in patients with RASopathies (Noonan syndrome and neurofibromatosis type 1 [NF1]), providing an additional link between these tumors and the mitogen-activated protein kinase (MAPK) signaling pathway. In summary, this case provides an example of the potential for genome-scale sequencing technologies to provide insight into the biology of rare tumors and yield both tumor and germline results of potential relevance to patient care.

Diagnostic Yield of Clinical Tumor and Germline Whole-Exome Sequencing for Children With Solid Tumors

Importance

Whole-exome sequencing (WES) has the potential to reveal tumor and germline mutations of clinical relevance, but the diagnostic yield for pediatric patients with solid tumors is unknown.

Objective

To characterize the diagnostic yield of combined tumor and germline WES for children with solid tumors.

Design

Unselected children with newly diagnosed and previously untreated central nervous system (CNS) and non-CNS solid tumors were prospectively enrolled in the BASIC3 study at a large academic children's hospital during a 23-month period from August 2012 through June 2014. Blood and tumor samples underwent WES in a certified clinical laboratory with genetic results categorized on the basis of perceived clinical relevance and entered in the electronic health record.

Main Outcomes and Measures

Clinical categorization of somatic mutations; frequencies of deleterious germline mutations related to patient phenotype and incidental medically-actionable mutations.

Results

Of the first 150 participants (80 boys and 70 girls, mean age, 7.4 years), tumor samples adequate for WES were available from 121 patients (81%). Somatic mutations of established clinical utility (category I) were reported in 4 (3%) of 121 patients, with mutations of potential utility (category II) detected in an additional 29 (24%) of 121 patients. CTNNB1 was the gene most frequently mutated, with recurrent mutations in KIT, TSC2, and MAPK pathway genes (BRAF, KRAS, and NRAS) also identified. Mutations in consensus cancer genes (category III) were found in an additional 24 (20%) of 121 tumors. Fewer than half of somatic mutations identified were in genes known to be recurrently mutated in the tumor type tested. Diagnostic germline findings related to patient phenotype were discovered in 15 (10%) of 150 cases: 13 pathogenic or likely pathogenic dominant mutations in adult and pediatric cancer susceptibility genes (including 2 each in TP53, VHL, and BRCA1), 1 recessive liver disorder with hepatocellular carcinoma (TJP2), and 1 renal diagnosis (CLCN5). Incidental findings were reported in 8 (5%) of 150 patients. Most patients harbored germline uncertain variants in cancer genes (98%), pharmacogenetic variants (89%), and recessive carrier mutations (85%).

Conclusions and Relevance

Tumor and germline WES revealed mutations in a broad spectrum of genes previously implicated in both adult and pediatric cancers. Combined reporting of tumor and germline WES identified diagnostic and/or potentially actionable findings in nearly 40% of newly diagnosed pediatric patients with solid tumors.

DW. Abstract 04: Impact of whole exome sequencing results on clinical decision making for pediatric solid tumor patients in the hypothetical scenario of tumor relapse: A survey of pediatric oncologists

Background: The development of molecularly-targeted agents has made it possible to personalize therapy for patients by targeting the specific mutations in their tumor. Pediatric clinical trials utilizing such strategies are being planned but little is known about the opinions of pediatric oncologists regarding the utility of genomic data for guiding treatment decisions. The goals of this study were to (1) characterize those opinions in the context of children with relapsed/refractory solid tumors and (2) assess the potential impact of clinical whole exome sequencing (WES) data on medical decision-making in that context.

Methods: As part of the ongoing BASIC3 clinical sequencing study at Texas Children's Cancer Center, clinical germline and tumor (if sample available) WES were performed for unselected newly-diagnosed pediatric CNS and non-CNS solid tumor patients. The primary oncologist for each (n=17) received online surveys for each study patient before and after review of WES reports. The pre- and post-WES surveys asked oncologists to rank options for off-study systemic chemotherapy (of any type) for their patient in the hypothetical scenario of tumor relapse. Oncologists were then asked if they would consider using a molecularly-targeted agent in the context of a clinical trial, and if so, which agents (from a representative list), their rank order and the rationale for those choices. Post-WES surveys also included questions regarding perceived utility of the tumor WES results for patient care. Pre-WES surveys were analyzed for baseline oncologist responses regarding these hypothetical treatment decisions. When available, pre- and post-WES surveys were analyzed as pairs as an initial assessment of the influence of the WES results on the oncologist's choice of therapy.

Results: 177/189 (94%) of pre-WES surveys and 111/161 (69%) post-WES surveys were available for analysis. Analysis of pre-exome surveys revealed that oncologists would recommend systemic chemotherapy for 127/177 (72%) patients in the hypothetical event of tumor relapse but would consider a molecularly-targeted agent off-study as their first option in only 8/177 (4%) cases. In contrast, oncologists indicated that they would consider targeted therapies in the context of a clinical trial for 99/177 (56%) patients, most commonly sorafenib (n=21), cixutumumab (n=17), and crizotinib (n=13). There were 26 cases in which somatic mutations were identified in genes categorized as having established or potential clinical relevance, and for which both pre- and post-WES surveys were available. A corresponding targeted agent was ranked for consideration in the hypothetical scenario of relapse on the post-WES survey for 8/26 (31%) of these patients (somatic mutations in MET, JAK2, HRAS, NRAS X 2, ALK, BRAF, KIT), having only been chosen on the pre-WES survey in 2 of those cases. On 8 of 111 (7%) post-WES surveys, the oncologist removed a targeted agent that had been prioritized on the pre-WES survey after no relevant mutation was detected, including the Sonic Hedgehog inhibitor GDC-0449 in 5 cases.

Conclusion: Although genomic tests such as WES have the potential to identify molecular targets for therapy in children with relapsed tumors, a survey of pediatric oncologists revealed that most consider such therapies as options only in the context of a clinical trial. These findings support the potential utility of WES in precision oncology approaches as well as the need for clinical trials evaluating the use of integrated genomic testing to guide treatment of children with relapsed solid tumors.

Citation Format: Abhishek Bavle, Tao Wang, Frank Y. Lin, Angshumoy Roy, Robin A. Kerstein, Sarah Scollon, Katie Bergstrom, Stephanie Gutierrez, Uma Ramamurthy, Yaping Yang, Christine M. Eng, Richard A. Gibbs, Murali M. Chintagumpala, Susan G. Hilsenbeck, Sharon E. Plon, Stacey L. Berg, D. Williams Parsons. Impact of whole exome sequencing results on clinical decision making for pediatric solid tumor patients in the hypothetical scenario of tumor relapse: A survey of pediatric oncologists. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Integrating Clinical Genomics and Cancer Therapy; Jun 13-16, 2015; Salt Lake City, UT. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(1_Suppl):Abstract nr 04.

Abstract IA16: Clinical genomics for children with solid tumors: Current realities and future opportunities

Genome-scale sequencing methods such as whole exome sequencing (WES) have provided significant insight into the pathogenesis of cancer. However, experience with the use of these tests in the clinical care of cancer patients remains limited. Sequencing of tumor and matched normal samples can reveal multiple types of results with implications for clinical practice. The identification of somatic (tumor-specific) mutations has the potential to offer diagnostic and prognostic information and inform selection of therapies. Detection of germline mutations in cancer susceptibility genes may prompt further genetic testing and guide cancer surveillance strategies for both the patient and family members. Germline mutations may also explain non-cancer phenotypes, predict drug responses, or provide reproductive counseling information for parents. The goal of the BASIC3 (Baylor College of Medicine Advancing Sequencing into Childhood Cancer Care) study is to determine the clinical impact of incorporating clinical tumor and constitutional WES into the care of children with newly diagnosed solid tumors. This study follows pediatric patients with newly diagnosed CNS and non-CNS solid tumors at Texas Children's Cancer Center for two years after performing CLIA-certified WES of blood and frozen tumor samples. Results are deposited into the electronic health record and disclosed to families by their oncologist and a genetic counselor. The potential impact of tumor exome findings on clinical decision-making is assessed through review of the medical record over the two year follow-up period as well as through surveys of the oncologists regarding prioritization of treatment options in the hypothetical event of tumor recurrence before and after receiving tumor exome results. Preferences of patient families and oncologists for reporting this complex information are obtained by interviews and audio recording of the WES result disclosure visits. Since the study opened in August 2012, more than 210 subjects have been enrolled (~80% of potentially eligible patients), representing the expected distribution of both CNS and non-CNS tumors. WES results have been reported for 170 subjects, revealing potentially-clinically relevant germline and somatic mutations in cancer genes known to be related to pediatric solid tumors as well as others known to be mutated primarily in adult cancer patients. Data will be presented regarding the diagnostic yield of combined tumor and germline WES for children with newly-diagnosed solid tumors. These results demonstrate the feasibility of routine tumor WES in the pediatric oncology clinic and a significant level of parental interest in receiving WES results and have significant implications for the treatment of children with relapsed and refractory solid tumors and the design of clinical trials using precision oncology approaches for these patients. Further analyses of the clinical utility of the WES data and the preferences of oncologists and parents for reporting of these results are under study. The BASIC3 study is a Clinical Sequencing Exploratory Research (CSER) program project supported by NHGRI/NCI 1U01HG006485.

Citation Format: D. William Parsons, Angshumoy Roy, Yaping Yang, Tao Wang, Sarah Scollon, Katie Bergstrom, Robin A. Kerstein, Stephanie Gutierrez, Abhishek Bavle, Frank Y. Lin, Dolores H. López-Terrada, Federico A. Monzon, Jed G. Nuchtern, Uma Ramamurthy, Amy L. McGuire, Susan G. Hilsenbeck, Jeffrey G. Reid, Donna M. Muzny, David A. Wheeler, Stacey L. Berg, Murali M. Chintagumpala, Christine M. Eng, Richard A. Gibbs, Sharon E. Plon. Clinical genomics for children with solid tumors: Current realities and future opportunities. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Integrating Clinical Genomics and Cancer Therapy; Jun 13-16, 2015; Salt Lake City, UT. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(1_Suppl):Abstract nr IA16.

Abstract 11: Evaluating cancer susceptibility mutations and incidental findings from whole exome sequencing of sequentially diagnosed pediatric solid and brain tumor patients: Early results of the BASIC3 study

Advances in sequencing technologies allow for provision of genome-scale data to oncologists and geneticists caring for pediatric cancer patients but current experience with the clinical application of genomic sequencing is limited. The goal of the BASIC3 (Baylor Advancing Sequencing into Childhood Cancer Care) study is to determine the clinical impact of incorporating tumor and constitutional whole exome sequencing (WES) into the care of children with newly diagnosed solid tumors at Texas Children's Cancer Center (target enrollment n=280). WES of patient blood and frozen tumor samples was conducted in the CLIA-certified Whole Genome Laboratory at Baylor College of Medicine using the vCrome 2.1 capture platform and Illumina paired-end sequencing. Reported WES germline findings were validated by a second platform and evaluated in parental blood samples if available, then deposited into the electronic medical record and disclosed to families by their oncologist and a genetic counselor. These disclosure visits are audio recorded and transcribed for analysis of the communication of WES results between parents and oncologists; in addition, the parents and oncologists are serially interviewed to determine preferences for reporting this complex information. Since the study opened in August 2012, 80% of 145 potentially eligible families have consented to enrollment. The first 100 patients comprise a diverse representation of diagnoses, including 32 with CNS tumors (32%) and 68 with non-CNS tumors (68%). The germline WES results (n=85 reported to date) included diagnostic findings in 10 cases including 7 patients with pathogenic mutations in dominant cancer susceptibility genes (all singletons except TP53 mutations identified in 2 patients). Only 3 of these 7 patients had genetic testing recommended clinically. There were 2 patients with mutations which identified the genetic cause of other (non-cancer) medical problems, and 1 study patient with mutations which explained both liver disease and hepatocellular carcinoma. Downstream testing of at-risk relatives has occurred rapidly in several families and cancer screening recommendations implemented in patients and family members. Seven medically actionable incidental findings unrelated to clinical phenotype have also been reported, predominantly in cardiovascular genes and mitochondrial DNA. The BASIC3 study demonstrates the feasibility of routine germline WES in the pediatric oncology clinic and a significant level of parental interest in receiving WES results. Early results suggest that clinically relevant susceptibility mutations can be identified in approximately 10% of unselected pediatric solid and brain tumor patients. This is a conservative estimate, as the WES data analysis does not currently report copy number variation in cancer susceptibility genes. A similar proportion of patients had incidental medically actionable mutations reported. The clinical utility of the germline WES data and the preferences of oncologists and parents for reporting of these results are under study. Supported by NHGRI/NCI 1U01HG006485.

Citation Format: Sharon E. Plon, Sarah Scollon, Katie Bergstrom, Robin A. Kerstein, Murali Chintagumpala, Stacey L. Berg, Susan G. Hilsenbeck, Tao Wang, Surya Rednam, David Wheeler, Laurence McCullough, Richard Street, Amy L. McGuire, Reid G. Jeffrey, Donna M. Muzny, Christine M. Eng, Yaping Yang, Richard A. Gibbs, Donald W. Parsons. Evaluating cancer susceptibility mutations and incidental findings from whole exome sequencing of sequentially diagnosed pediatric solid and brain tumor patients: Early results of the BASIC3 study. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Susceptibility and Cancer Susceptibility Syndromes; Jan 29-Feb 1, 2014; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(23 Suppl):Abstract nr 11. doi:10.1158/1538-7445.CANSUSC14-11

Abstract 5169: Diagnostic yield of clinical tumor and germline exome sequencing for newly diagnosed children with solid tumors

Background: Advances in sequencing technologies allow for provision of genome-scale data to physicians caring for pediatric cancer patients but current experience with the clinical application of genomic sequencing is limited and the diagnostic yield of these methods is unclear.

Methods: The goal of the BASIC3 (Baylor Advancing Sequencing into Childhood Cancer Care) study is to determine the clinical impact of incorporating tumor and constitutional whole exome sequencing (WES) into the care of children with newly diagnosed solid tumors at Texas Children's Cancer Center (target enrollment n=280). WES of patient blood and frozen tumor samples is being conducted in the CLIA-certified Whole Genome Laboratory at Baylor College of Medicine using the VCRome 2.1 capture reagent and Illumina paired-end sequencing with reports incorporated in the medical record.

Results: 120 patients have enrolled to date, including 39 (33%) and 81 (67%) with CNS and non-CNS tumors, respectively. Despite limited diagnostic biopsies in many patients, tumor samples adequate for WES have been obtained from 97 subjects (81%). WES results have been reported for 89 patients. Tumor WES (n=73) revealed 20 of 73 tumors (27%) to contain mutations classified as having proven or potential clinical utility, including recurrent alterations of CTNNB1, BRAF, KIT, and NRAS/KRAS. Notably, less than 50% of somatic mutations would have been detected on an adult-focused cancer panel, BCM Cancer Gene Mutation Panel v.2. Germline WES (n=89) identified diagnostic findings in 11 cases (12%) including 8 patients with pathogenic mutations in dominant cancer susceptibility genes (singletons except for 2 patients with TP53 mutations). Four of these 8 patients had genetic testing recommended clinically. There were 2 patients with mutations providing the genetic cause of non-cancer medical problems and 1 patient with a mutation which explained both liver disease and hepatocellular carcinoma. Downstream testing of at-risk relatives has occurred rapidly in several families and cancer screening recommendations implemented. Seven (8%) medically actionable incidental findings unrelated to phenotype were reported, predominantly in cardiovascular genes and mitochondrial DNA.

Conclusions: These data demonstrate the feasibility of routine WES in the pediatric oncology setting. Early results demonstrate that clinically relevant findings are identified by tumor and germline WES in 38% of pediatric solid tumor patients. The yield of clinically relevant somatic and germline alterations would likely increase further by incorporation of complementary genomic methods (e.g. RNA-seq or copy number analysis). Assessment of the clinical utility of the tumor and germline exomes and preferences for reporting of these results to physicians and parents are under study. Supported by NHGRI/NCI 1U01HG006485.

Citation Format: Donald W. Parsons, Angshumoy Roy, Federico A. Monzon, Yaping Yang, Dolores H. López-Terrada, Murali M. Chintagumpala, Stacey L. Berg, Susan G. Hilsenbeck, Tao Wang, Robin A. Kerstein, Sarah Scollon, Katie Bergstrom, Richard L. Street, Laurence B. McCullough, Amy L. McGuire, Uma Ramamurthy, Jeff G. Reid, Donna M. Muzny, David A. Wheeler, Christine M. Eng, Richard A. Gibbs, Sharon E. Plon. Diagnostic yield of clinical tumor and germline exome sequencing for newly diagnosed children with solid tumors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5169. doi:10.1158/1538-7445.AM2014-5169

Obtaining informed consent for clinical tumor and germline exome sequencing of newly diagnosed childhood cancer patients

BACKGROUND

Effectively educating families about the risks and benefits of genomic tests such as whole exome sequencing (WES) offers numerous challenges, including the complexity of test results and potential loss of privacy. Research on best practices for obtaining informed consent (IC) in a variety of clinical settings is needed. The BASIC3 study of clinical tumor and germline WES in an ethnically diverse cohort of newly diagnosed pediatric cancer patients offers the opportunity to study the IC process in the setting of critical illness. We report on our experience for the first 100 families enrolled, including study participation rates, reasons for declining enrollment, assessment of clinical and demographic factors that might impact study enrollment, and preferences of parents for participation in optional genomics study procedures.

METHODS

A specifically trained IC team offered study enrollment to parents of eligible children for procedures including clinical tumor and germline WES with results deposited in the medical record and disclosure of both diagnostic and incidental results to the family. Optional study procedures were also offered, such as receiving recessive carrier status and deposition of data into research databases. Stated reasons for declining participation were recorded. Clinical and demographic data were collected and comparisons made between enrolled and non-enrolled patients.

RESULTS

Over 15 months, 100 of 121 (83%) eligible families elected to enroll in the study. No significant differences in enrollment were detected based on factors such as race, ethnicity, use of Spanish interpreters and Spanish consent forms, and tumor features (central nervous system versus non-central nervous system, availability of tumor for WES). The most common reason provided for declining enrollment (10% of families) was being overwhelmed by the new cancer diagnosis. Risks specific to clinical genomics, such as privacy concerns, were less commonly reported (5.5%). More than 85% of parents consented to each of the optional study procedures.

CONCLUSIONS

An IC process was developed that utilizes a specialized IC team, active communication with the oncology team, and an emphasis on scheduling flexibility. Most parents were willing to participate in a clinical germline and tumor WES study as well as optional procedures such as genomic data sharing independent of race, ethnicity or language spoken.

Pharmacokinetics and pharmacogenomics of daunorubicin in children: a report from the Children's Oncology Group

PURPOSE

We explored the impact of obesity, body composition, and genetic polymorphisms on the pharmacokinetics (PK) of daunorubicin in children with cancer.

PATIENTS AND METHODS

Patients ≤21 years receiving daunorubicin as an infusion of any duration <24 h for any type of cancer were eligible. Plasma drug concentrations were measured by high-performance liquid chromatography. Body composition was measured by dual-energy X-ray absorptiometry. Obesity was defined as a BMI >95% for age or as body fat >30%. NONMEM was used to perform PK model fitting. The Affymetrix DMET chip was used for genotyping. The impact of genetic polymorphisms was investigated using SNP/haplotype association analysis with estimated individual PK parameters.

RESULTS

A total of 107 subjects were enrolled, 98 patients had PK sampling, and 50 patients underwent DNA analysis. Population estimates for daunorubicin clearance and volume of distribution were 116 L/m(2)/h ± 14% and 68.1 L/m(2) ± 24%, respectively. Apparent daunorubicinol clearance and volume of distribution were 26.8 L/m(2)/h ± 5.6% and 232 L/m(2) ± 10%, respectively. No effect of body composition or obesity was observed on PK. Forty-four genes with variant haplotypes were tested for association with PK. FMO3-H1/H3 genotype was associated with lower daunorubicin clearance than FMO3-H1/H1, p = 0.00829. GSTP1*B/*B genotype was also associated with lower daunorubicin clearance compared to GSTP1*A/*A, p = 0.0347. However, neither of these associations was significant after adjusting for multiple testing by either Bonferroni or false discovery rate correction.

CONCLUSIONS

We did not detect an effect of body composition or obesity on daunorubicin PK. We found suggestive associations between FMO3 and GSTP1 haplotypes with daunorubicin PK that could potentially affect efficacy and toxicity.

Pharmacokinetics of doxorubicin in pregnant women

PURPOSE

Our objective was to evaluate the pharmacokinetics (PK) of doxorubicin during pregnancy compared to previously published data from non-pregnant subjects.

METHODS

During mid- to late-pregnancy, serial blood and urine samples were collected over 72 h from seven women treated with doxorubicin for malignancies. PK parameters were estimated using non-compartmental techniques. Pregnancy parameters were compared to those previously reported non-pregnant subjects.

RESULTS

During pregnancy, mean (±SD) doxorubicin PK parameters utilizing 72 h sampling were: clearance (CL), 412 ± 80 mL/min/m(2); steady-state volume of distribution (Vss), 1,132 ± 476 L/m(2); and terminal half-life (T1/2), 40.3 ± 8.9 h. The BSA-adjusted CL was significantly decreased (p < 0.01) and T1/2 was not different compared to non-pregnant women. Truncating our data to 48 h, PK parameters were: CL, 499 ± 116 ml/min/m(2); Vss, 843 ± 391 L/m(2); and T1/2, 24.8 ± 5.9 h. The BSA-adjusted CL in pregnancy compared to non-pregnant data was significantly decreased in 2 of 3 non-pregnant studies (p < 0.05, < 0.05, NS). Vss and T1/2 were not significantly different.

CONCLUSIONS

In pregnant subjects, we observed significantly lower doxorubicin CL in our 72 h and most of our 48 h sampling comparisons with previously reported non-pregnant subjects. However, the parameters were within the range previously reported in smaller studies. At this time, we cannot recommend alternate dosage strategies for pregnant women. Further research is needed to understand the mechanism of doxorubicin pharmacokinetic changes during pregnancy and optimize care for pregnant women.

Implementation and evaluation of clinical exome sequencing in childhood cancer care: The BASIC3 study

10023

Background: Advances in sequencing technologies allow for provision of genome-scale data to oncologists and geneticists caring for pediatric cancer patients. The goal of the BASIC3 (Baylor Advancing Sequencing into Childhood Cancer Care) study is to determine the clinical impact of incorporating CLIA-certified tumor and constitutional exome sequencing into the care of children with newly diagnosed solid tumors. Methods: Blood and frozen tumor samples obtained at initial surgery are submitted for clinical exome sequencing (target enrollment 280 patients). Results are deposited into the electronic medical record and disclosed to families by their oncologist and a genetic counselor. Identification of germline cancer susceptibility mutations is compared with standard testing practices. Oncologists are surveyed on prioritization of treatment options in the hypothetical event of tumor recurrence before and after receiving tumor exome results. Patients will be followed for two years to assess the clinical utility of exome data. Preferences for reporting this complex information are obtained by interviews and audiorecording of disclosure visits. Results: Initial results reveal that41 of 49 (84%) ethnically diverse families have consented to enroll on study. Adequate tumor samples were available from 35 of 41 patients (85%), including 11 of 15 (73%) patients with CNS tumors and 24 of 26 (92%) with non-CNS tumors. Pathogenic germline cancer susceptibility mutations (TP53, MSH2) were reported in 2 of the first 11 patients, with a medically-actionable mutation in a gene (SCN5A) unrelated to cancer in 1 patient and 0-4 (median of 2) recessive carrier mutations per patient. Between 9 and 33 protein altering mutations (median of 11) have been identified in tumors, including known cancer genes such as TP53 and others with no known link to pediatric cancer. Conclusions: A robust clinical pipeline for exome sequencing of blood and tumor samples has been successfully developed with significant parental interest. Data assessing the clinical utility of both the tumor and constitutional exomes and the preferences of oncologists and parents for reporting of these results are under study. Supported by NHGRI 1U01HG006485.

A phase-1 pharmacokinetic optimal dosing study of intraventricular topotecan for children with neoplastic meningitis: a Pediatric Brain Tumor Consortium study

PURPOSE

We performed a phase-1 pharmacokinetic optimal dosing study of intraventricular topotecan (IT), administered daily 5×, to determine whether, the maximum tolerated dose of IT topotecan was also the pharmacokinetic optimal dose.

PATIENTS AND METHODS

Patients received topotecan administered through an intraventricular access device (0.1 or 0.2 mg/dose), daily × 5 every other week 2× (Induction); every 3 weeks × 2 (Consolidation); then every 4 weeks for up to 11 courses (Maintenance). Ventricular CSF pharmacokinetic studies were performed on day 1, week 1 of induction, and in a subset of patients after a single intralumbar topotecan dose on day 1, week 3.

RESULTS

Nineteen patients were enrolled. All were evaluable for toxicity and 18 were assessable for pharmacokinetics. Arachnoiditis requiring corticosteroid therapy occurred in or one of three patients at the 0.1 mg dose level and two of the initial three patients enrolled at the 0.2 mg dose level. All subsequent patients were therefore treated with concomitant dexamethasone. Pharmacokinetic evaluation after accrual of the first seven patients revealed that a topotecan lactone concentration >1 ng/ml for 8 hours was attained in all patients and thus, further dose escalation was not pursued. Results of simulation studies showed that at the dose levels evaluated, >99.9% of patients are expected to achieve CSF topotecan lactone concentrations >1 ng/ml for at least 8 hours.

CONCLUSION

Intraventricular topotecan, 0.2 mg, administered daily for 5 days with concomitant dexamethasone is well tolerated and was defined to be the pharmacokinetic optimal dose in this trial.

Plasma and cerebrospinal fluid pharmacokinetics of thalidomide and lenalidomide in nonhuman primates

PURPOSE

Thalidomide, originally developed as a sedative, was subsequently identified to have antiangiogenic properties. Lenalidomide is an antiangiogenic and immunomodulatory agent that has been utilized in the treatment of patients with brain tumors. We studied the pharmacokinetics and cerebrospinal fluid (CSF) penetration of thalidomide and lenalidomide in a nonhuman primate model.

METHODS

A dose of 50 mg of thalidomide or 20 mg of lenalidomide was administered once orally to each of three rhesus monkeys. Plasma and CSF samples were obtained at specified intervals, and the thalidomide or lenalidomide concentrations were determined by high-performance liquid chromatography with tandem mass spectrometry. Pharmacokinetic parameters were estimated using noncompartmental methods. CSF penetration was calculated as area under the concentration-time curve (AUC) CSF/AUC plasma.

RESULTS

For thalidomide, the median apparent clearance (Cl/F) was 2.9 mL/min/kg, the median plasma AUC was 80 μM h, and the median terminal half-life (t(½)) was 13.3 h. For lenalidomide, the median Cl/F was 8.7 mL/min/kg, the median AUC was 9 μM h, and the median t(½) was 5.6 h. Thalidomide was detected in the CSF of all animals, with a median penetration of 42%. Lenalidomide was detected in the CSF of 2 of 3 animals, with a CSF penetration of 11% in each.

CONCLUSION

Thalidomide and lenalidomide penetrate into the CSF after oral administration of clinically relevant doses. Plasma exposure to lenalidomide was similar in our model to that observed in studies involving children who have brain tumors. These results support further development of lenalidomide for the treatment of central nervous system malignancies.

A phase II study of O6-benzylguanine and temozolomide in pediatric patients with recurrent or progressive high-grade gliomas and brainstem gliomas: a Pediatric Brain Tumor Consortium study

To estimate the sustained (≥8 weeks) objective response rate in pediatric patients with recurrent or progressive high-grade gliomas (HGG, Stratum A) or brainstem gliomas (BSG, Stratum B) treated with the combination of O6-benzylguanine (O6BG) and temozolomide(®) (TMZ). Patients received O6BG 120 mg/m(2)/d IV followed by TMZ 75 mg/m(2)/d orally daily for 5 consecutive days of each 28-day course. The target objective response rate to consider the combination active was 17%. A two-stage design was employed. Forty-three patients were enrolled; 41 were evaluable for response, including 25 patients with HGG and 16 patients with BSG. The combination of O6BG and TMZ was tolerable, and the primary toxicities were myelosuppression and gastrointestinal symptoms. One sustained (≥8 weeks) partial response was observed in the HGG cohort; no sustained objective responses were observed in the BSG cohort. Long-term (≥6 courses) stable disease (SD) was observed in 4 patients in Stratum A and 1 patient in Stratum B. Of the 5 patients with objective response or long-term SD, 3 underwent central review with 2 reclassified as low-grade gliomas. The combination of O6BG and TMZ did not achieve the target response rate for activity in pediatric patients with recurrent or progressive HGG and BSG.

Safety, pharmacokinetics, and immunomodulatory effects of lenalidomide in children and adolescents with relapsed/refractory solid tumors or myelodysplastic syndrome: a Children's Oncology Group Phase I Consortium report

PURPOSE

To determine the maximum-tolerated or recommended phase II dose, dose-limiting toxicities (DLTs), pharmacokinetics (PK), and immunomodulatory effects of lenalidomide in children with recurrent or refractory solid tumors or myelodysplastic syndrome (MDS).

PATIENTS AND METHODS

Cohorts of children with solid tumors received lenalidomide once daily for 21 days, every 28 days at dose levels of 15 to 70 mg/m(2)/dose. Children with MDS received a fixed dose of 5 mg/m(2)/dose. Specimens for PK and immune modulation were obtained in the first cycle.

RESULTS

Forty-nine patients (46 solid tumor, three MDS), median age 16 years (range, 1 to 21 years), were enrolled, and 42 were fully assessable for toxicity. One patient had a cerebrovascular ischemic event of uncertain relationship to lenalidomide. DLTs included hypercalcemia at 15 mg/m(2); hypophosphatemia/hypokalemia, neutropenia, and somnolence at 40 mg/m(2); and urticaria at 55 mg/m(2). At the highest dose level evaluated (70 mg/m(2)), zero of six patients had DLT. A maximum-tolerated dose was not reached. No objective responses were observed. PK studies (n = 29) showed that clearance is faster in children younger than 12 years of age. Immunomodulatory studies (n = 26) showed a significant increase in serum interleukin (IL) -2, IL-15, granulocyte-macrophage colony-stimulating factor, natural killer (NK) cells, NK cytotoxicity, and lymphokine activated killer (LAK) cytoxicity, and a significant decrease in CD4(+)/CD25(+) regulatory T cells.

CONCLUSION

Lenalidomide is well-tolerated at doses up to 70 mg/m(2)/d for 21 days in children with solid tumors. Drug clearance in children younger than 12 years is faster than in adolescents and young adults. Lenalidomide significantly upregulates cellular immunity, including NK and LAK activity.

Reasons for participation in optional pharmacokinetic studies in children with cancer: a Children's Oncology Group phase 1 consortium study

PURPOSE

Pharmacokinetic (PK) studies provide critical information about the disposition of anticancer drugs in children. In the Children's Oncology Group (COG) Phase 1 Consortium, pharmacokinetic studies are usually optional. We surveyed the attitudes towards PK studies among subjects in phase 1 trials at COG institutions.

METHODS

Subjects were eligible if they participated in a phase 1 anticancer drug study with optional PK studies within the 4 weeks, regardless of whether they agreed to participate in the PK studies. Staff provided demographics; subjects/parents completed a questionnaire.

RESULTS

Fifty eligible subjects enrolled. Thirty-six (72%) of the 50 eligible subjects consented to participate in PK studies; 14 (25%) declined. The most common reasons for participating were "the results might help researchers learn more about the drug" and "results from the pharmacokinetic studies might help other children." The most common reasons for not participating were "having the samples drawn would mean spending extra time in the hospital," and "my child might have needed a separate IV catheter in order to participate."

CONCLUSIONS

The majority of subjects identified altruistic motives for participation in PK studies. Subjects who did not participate in PK studies identified extra time and need for an extra IV as important concerns. Simple interventions like sending staff to the subjects' home to draw PK samples or drawing samples from existing catheters could increase the number of subjects who are willing to participate in PK studies.

Poly(ADP-ribose) polymerase inhibitor ABT-888 potentiates the cytotoxic activity of temozolomide in leukemia cells: influence of mismatch repair status and O6-methylguanine-DNA methyltransferase activity

The poly(ADP-ribose) polymerase (PARP) inhibitor ABT-888 potentiates the antitumor activity of temozolomide (TMZ). TMZ resistance results from increased O(6)-methylguanine-DNA methyltransferase (MGMT) activity and from mismatch repair (MMR) system mutations. We evaluated the relative importance of MGMT activity, MMR deficiency, nonhomologous end joining (NHEJ), and PARP activity in ABT-888 potentiation of TMZ. MMR-proficient and MMR-deficient leukemia cells with varying MGMT activity, as well as primary leukemia samples, were used to determine TMZ IC(50) alone and with ABT-888. ABT-888 effectively inhibited PARP activity and enhanced TMZ growth inhibition in most leukemia cells. ABT-888 potentiation was most effective in MMR-deficient cells with low MGMT activity [potentiation factor (PF) = 21]. ABT-888 also potentiated TMZ activity in MMR-deficient cells with elevated MGMT activity. Unexpectedly, ABT-888 also enhanced TMZ activity in MMR-proficient cells (PF = 3-7). ABT-888 potentiation was unrelated to NHEJ activity. ABT-888 potentiated TMZ (PF = 2-5) in two of four acute myeloid leukemia patient samples but showed little potentiation in primary acute lymphoblastic leukemia. In conclusion, although ABT-888 potentiation of TMZ was most pronounced in MMR-deficient cells with low MGMT activity, neither MMR proficiency nor MGMT overexpression completely abrogated ABT-888 potentiation of TMZ.