A phase 1/2 study of pepinemab in children, adolescents, or young adults with recurrent or refractory solid tumors: A children's oncology group consortium report (ADVL1614)

PURPOSE

Pepinemab, a humanized IgG4 monoclonal antibody, targets the SEMA4D (CD100) antigen to inhibit binding to its high-affinity receptors (plexin B1/PLXNB1, plexin B2/PLXNB2) and low-affinity receptor (CD72). SEMA4D blockade leads to increased cytotoxic T-cell infiltration, delayed tumor growth, and durable tumor rejection in murine tumor models. Pepinemab was well tolerated and improved T cell infiltration in clinical studies in adults with refractory tumors. SEMA4D was identified as a strong candidate proto-oncogene in a model of osteosarcoma. Based on these preclinical and clinical data, we conducted a phase 1/2 study to determine the recommended phase 2 dose (RP2D), pharmacokinetics, pharmacodynamics, and immunogenicity, of pepinemab in pediatric patients with recurrent/refractory solid tumors, and activity in osteosarcoma.

EXPERIMENTAL DESIGN

Pepinemab was administered intravenously on Days 1 and 15 of a 28-day cycle at 20 mg/kg, the adult RP2D. Part A (phase 1) used a Rolling 6 design; Part B (phase 2) used a Simon 2-stage design in patients with osteosarcoma. Pharmacokinetics and target saturation were evaluated in peripheral blood.

RESULTS

Pepinemab (20 mg/kg) was well tolerated and no dose-limiting toxicities were observed during Part A. There were no objective responses. Two patients with osteosarcoma achieved disease control and prolonged stable disease. Pepinemab pharmacokinetics were similar to adults.

CONCLUSIONS

Pepinemab (20 mg/kg) is safe, well tolerated and resulted in adequate and sustained target saturation in pediatric patients. Encouraging disease control in two patients with osteosarcoma warrants further investigation with novel combination strategies to modulate the tumor microenvironment and antitumor immune response.

CLINICAL TRIAL REGISTRY

This trial is registered as NCT03320330 at Clinicaltrials.gov.

DISCLAIMER

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Sex differences in osteosarcoma survival across the age spectrum: A National Cancer Database analysis (2004-2016)

BACKGROUND

Osteosarcoma displays a bimodal peak in incidence in adolescence and later adulthood. Males are more frequently diagnosed with osteosarcoma in both periods. Males have worse survival than females, which is generally poor at 30-70% 5-years post diagnosis, depending on age, but treatment received is often unaccounted for in survival analyses.

METHODS

Therefore, we estimated sex differences in survival for children and adults stratifying by treatment received and other disease characteristics using the National Cancer Database (2004-2016, n=9017). We estimated sex differences in long-term survival using Kaplan Meier survival curves and Log-Rank p-values. We also estimated hazard ratios (HR) and 95% confidence intervals (CIs) as the measure of association between sex and death using Cox regression.

RESULTS

In all age groups, cases were predominantly male (52-58%). In Kaplan-Meier analyses, males had worse overall survival than females for 0-19, 20-39, and ≥60-year-olds (Log-Rank p<0.05). Females had higher 5- and 10-year survival percentages in all age groups. In adjusted Cox models, males had a higher risk of death among 0-19-year-olds (HRoverall: 1.24, 95% CI: 1.06-1.44; HRnon-metastatic disease: 1.35, 95% CI: 1.12, 1.63, HRlower limb tumors: 1.31, 95% CI: 1.09-1.59). Among 20-39-year-olds, males had an increased risk of death when receiving surgery only (HR: 4.67, 95% CI: 1.44, 15.09). Among those ≥60-year-olds, males had a suggestive increased risk of death overall (HR: 1.17, 95% CI: 0.99-1.39) and a higher risk of death based on some tumor locations, (HRupper limb: 2.52, 95% CI: 1.24, 5.11; HRmidline: 1.36, 95% CI: 1.02, 1.82).

CONCLUSIONS

Our findings suggest that the worse survival among young males compared to females with osteosarcoma persisted after accounting for many major disease characteristics, including treatment received. Collectively, our work points toward other unexplored mechanisms beyond treatment, potentially biologic or otherwise, which may be driving the observed sex differences in long-term survival.

A phase 1 trial utilizing a pharmacokinetic endpoint to determine the optimal dose of ramucirumab in children and adolescents with relapsed or refractory solid tumors, including central nervous system tumors

BACKGROUND

Ramucirumab is a monoclonal antibody that binds the extracellular domain of vascular endothelial growth factor receptor (VEGFR-2) and prevents binding of VEGF ligands. Based on population pharmacokinetic (PK) analysis and correlation with efficacy in adults, a target steady state trough concentration (Css,min ) ≥ 50 µg/mL was established.

PROCEDURES

This phase 1 trial (ADVL1416) used a rolling six design and a PK primary endpoint to define the recommended phase 2 dose (RP2D) of ramucirumab in children with recurrent/refractory solid tumors. Two dose levels (DL) were planned (DL1: 8 mg/kg, DL2: 12 mg/kg administered intravenously [IV] every 2 weeks). Toxicity during the initial 6 weeks was used to assess maximum tolerated dose (MTD). Cycle 1 Day 42 trough (Cmin ) ≥ 50 µg/mL was the target concentration for the PK endpoint. At the RP2D, cohorts for PK expansion and children with central nervous tumors were planned.

RESULTS

Twenty-nine patients were enrolled; 28 were eligible; median age [range] = 13.5 [1-21] years; 22 were evaluable for the PK endpoint. Dose-limiting proteinuria occurred at both DLs; however, the MTD was not exceeded. At DL2 (12 mg/kg), the median Day 42 Cmin (n = 16) was 87.8 µg/mL; 15 of 16 patients achieved a Cmin  ≥ 50 µg/mL.

CONCLUSION

Ramucirumab was well tolerated in children and adolescents with solid tumors. The RP2D for ramucirumab was 12 mg/kg IV every 2 weeks. This trial demonstrates the feasibility of incorporating a primary PK endpoint to determine dose escalation and the RP2D in children. Studies of ramucirumab in children with selected solid tumors are ongoing.

Feasibility of pevonedistat combined with azacitidine, fludarabine, cytarabine in pediatric relapsed/refractory AML: Results from COG ADVL1712

BACKGROUND

Outcomes for children with relapsed/refractory (R/R) acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are poor, and new therapies are needed. Pevonedistat is an inhibitor of the NEDD-8 activating enzyme, a key regulator of the ubiquitin proteasome system that is responsible for protein turnover, with protein degradation regulating cell growth and survival.

PROCEDURE

We evaluated the feasibility, toxicity, and pharmacokinetics (PK) of pevonedistat (20 mg/m2 days 1, 3, 5) in combination with azacitidine, fludarabine, cytarabine (aza-FLA) in children with R/R AML and MDS (NCT03813147). Twelve patients were enrolled, median age was 13 years (range 1-21). Median number of prior chemotherapeutic regimens was two (range one to five), and two (25%) patients had prior hematopoietic cell transplantation. Diagnoses were AML NOS (n = 10, 83%), acute monocytic leukemia (n = 1), and therapy-related AML (n = 1).

RESULTS

Overall, three of 12 (25%) patients experienced DLTs. The day 1 mean ± SD (n = 12) Cmax , VSS , T1/2 , and CL were 223 ± 91 ng/mL, 104 ± 53.8 L/m2 , 4.3 ± 1.2 hours, and 23.2 ± 6.9 L/h/m2 , respectively. T1/2 , VSS , and Cmax , but not CL, were significantly different between age groups. The overall response rate was 25%, with n = 3 patients achieving a complete remission with incomplete hematologic recovery (CRi).

CONCLUSIONS

Pevonedistat 20 mg/m2 combined with Aza-FLA was tolerable in children with R/R AML with similar toxicity profile to other intensive AML regimens. However, within the confines of a phase 1 study, we did not observe that the pevonedistat + Aza-FLA combination demonstrated significant anti-leukemic activity.

Palbociclib in combination with chemotherapy in pediatric and young adult patients with relapsed/refractory acute lymphoblastic leukemia and lymphoma: A Children's Oncology Group study (AINV18P1)

BACKGROUND

Cyclin D has been shown to play an essential role in acute lymphoblastic leukemia (ALL) initiation and progression, providing rationale for targeting the CDK4/6-cyclin D complex that regulates cell cycle progression.

PROCEDURE

The Children's Oncology Group AINV18P1 phase 1 trial evaluated the CDK4/6 inhibitor, palbociclib, in combination with standard four-drug re-induction chemotherapy in children and young adults with relapsed/refractory B- and T-cell lymphoblastic leukemia (ALL) and lymphoma. Palbociclib (50 mg/m2 /dose) was administered orally once daily for 21 consecutive days, first as a single agent (Days 1-3) and subsequently combined with re-induction chemotherapy. This two-part study was designed to determine the maximum tolerated dose (MTD) or recommended phase 2 dose (RP2D), followed by an expansion pharmacokinetic cohort.

RESULTS

Twelve heavily pretreated patients enrolled, all of whom were evaluable for toxicity. One dose-limiting hematologic toxicity (DLT) occurred at the starting dose of 50 mg/m2 /dose orally for 21 days. No additional DLTs were observed in the dose determination or pharmacokinetic expansion cohorts, and overall rates of grade 3/4 nonhematologic toxicities were comparable to those observed with the chemotherapy platform alone. Five complete responses were observed, two among four patients with T-ALL and three among seven patients with B-ALL. Pharmacokinetic studies showed similar profiles with both liquid and capsule formulations of palbociclib.

CONCLUSIONS

Palbociclib in combination with re-induction chemotherapy was well tolerated with a RP2D of 50 mg/m2 /day for 21 days. Complete responses were observed among heavily pretreated patients.

Children's Oncology Group's 2023 blueprint for research: Developmental therapeutics

The Developmental Therapeutics Committee (DVL) identifies and develops new agents and treatment strategies for children/adolescents with cancer, through clinical and translational research. DVL has focused on evaluating the activity of targeted therapy and has evolved from trials with multiple histology strata to biomarker-selected phase 2 trials. These trials have included single-agent studies to evaluate agents such as cabozantinib in multi-disease cohorts, to trametinib, larotrectinib, and lorvotuzumab in disease-specific cohorts, as well as the pediatric Molecular Analysis for Therapy Choice (MATCH) study including multiple single agents targeted for biomarker-selected pediatric tumors. The ongoing vision and direction of DVL is to support the disease committees of COG to develop novel agents and combinations to advance the care of children with cancer.

Pediatric phase 2 trial of a WEE1 inhibitor, adavosertib (AZD1775), and irinotecan for relapsed neuroblastoma, medulloblastoma, and rhabdomyosarcoma

BACKGROUND

Inhibition of the WEE1 kinase by adavosertib (AZD1775) potentiates replicative stress from genomic instability or chemotherapy. This study reports the pediatric solid tumor phase 2 results of the ADVL1312 trial combining irinotecan and adavosertib.

METHODS

Pediatric patients with recurrent neuroblastoma (part B), medulloblastoma/central nervous system embryonal tumors (part C), or rhabdomyosarcoma (part D) were treated with irinotecan and adavosertib orally for 5 days every 21 days. The combination was considered effective if there were at least three of 20 responses in parts B and D or six of 19 responses in part C. Tumor tissue was analyzed for alternative lengthening of telomeres and ATRX. Patient's prior tumor genomic analyses were provided.

RESULTS

The 20 patients with neuroblastoma (part B) had a median of three prior regimens and 95% had a history of prior irinotecan. There were three objective responses (9, 11, and 18 cycles) meeting the protocol defined efficacy end point. Two of the three patients with objective responses had tumors with alternative lengthening of telomeres. One patient with pineoblastoma had a partial response (11 cycles), but parts C and D did not meet the protocol defined efficacy end point. The combination was well tolerated and there were no dose limiting toxicities at cycle 1 or beyond in any parts of ADVL1312 at the recommended phase 2 dose.

CONCLUSION

This is first phase 2 clinical trial of adavosertib in pediatrics and the first with irinotecan. The combination may be of sufficient activity to consider further study of adavosertib in neuroblastoma.

Rhabdomyosarcoma with isolated lung metastases: A report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

BACKGROUND

To determine outcomes of children with rhabdomyosarcoma (RMS) with isolated lung metastases.

METHODS

Data were analyzed for 428 patients with metastatic RMS treated on COG protocols. Categorical variables were compared using Chi-square or Fisher's exact tests. Event-free survival (EFS) and overall survival (OS) were estimated using Kaplan-Meier method and compared using the log-rank test.

RESULTS

Compared with patients with other metastatic sites (n = 373), patients with lung-only metastases (n = 55) were more likely to be <10 years of age, have embryonal histology (embryonal rhabdomyosarcoma), have N0 disease, and less likely to have primary extremity tumors. Lung-only patients had significantly better survival outcomes than patients with all other sites of metastatic disease (p < .0001) with 5-year EFS of 48.1 versus 18.8% and 5-year OS of 64.1 versus 26.9%. Patients with lung-only metastases, and those with a single extrapulmonary site of metastasis, had better survival compared with patients with two or more sites of metastatic disease (p < .0001). In patients with ERMS and lung-only metastases, there was no significant difference in survival between patients ≥10 years and 1-9 years (5-year EFS: 58.3 vs. 68.2%, 5-year OS: 66.7 vs. 67.7%).

CONCLUSIONS

With aggressive treatment, patients with ERMS and lung-only metastatic disease have superior EFS and OS compared with patients with other sites of metastatic disease, even when older than 10 years of age. Consideration should be given to including patients ≥10 years with ERMS and lung-only metastases in the same group as those <10 years in future risk stratification algorithms.

A Phase I/II Trial of Nivolumab plus Ipilimumab in Children and Young Adults with Relapsed/Refractory Solid Tumors: A Children's Oncology Group Study ADVL1412

PURPOSE

In many cancers, nivolumab in combination with ipilimumab improves response rates compared with either agent alone, but the combination has not been evaluated in childhood cancer. We conducted a phase I/II trial of nivolumab plus ipilimumab in children and young adults with recurrent/refractory solid tumors.

PATIENTS AND METHODS

ADVL1412, Part C assessed safety of nivolumab plus ipilimumab at two dose levels (DL): DL1 1 mg/kg of each drug and DL2 3 mg/kg nivolumab plus 1 mg/kg ipilimumab. Part D evaluated response at the recommended phase II dose (RP2D) in Ewing sarcoma, rhabdomyosarcoma, and osteosarcoma. Part E tested DL3 (1 mg/kg nivolumab plus 3 mg/kg ipilimumab) in Ewing sarcoma and rhabdomyosarcoma. Tumor response was measured using RECIST v1.1. Pharmacokinetics and PD-L1 expression on archival tissues were assessed.

RESULTS

Fifty-five eligible patients enrolled. Based on safety, tolerability, and similar drug exposure to the same doses administered in adults, DL2 was defined as the pediatric RP2D. Among 41 patients treated at the RP2D, 2 patients experienced dose-limiting toxicities during cycle 1, and 4 patients experienced toxicities beyond that period. Two patients had clinically significant sustained partial responses (1 rhabdomyosarcoma, 1 Ewing sarcoma) and 4 had stable disease. Among 8 patients treated at DL3, 3 dose-limiting toxicities (DLT) occurred, all immune-related adverse events; no objective responses were observed.

CONCLUSIONS

The RP2D of nivolumab (3 mg/kg) plus ipilimumab (1 mg/kg) is well tolerated in children and young adults with solid tumors and shows some clinical activity. Increased dose of ipilimumab (3 mg/kg) plus nivolumab (1 mg/kg) was associated with increased toxicity without clinical benefit.

Congenital Infantile Fibrosarcoma Involving Pelvic Wall and Thigh Soft Tissues and Placenta, Presenting with Coagulopathy

Infantile fibrosarcoma (IF) is a well characterized pediatric malignancy marked by gene rearrangements involving members of the NTRK family. In this report, we present a case of IF that presented in the inguinal region-proximal thigh and was initially thought to be a kaposiform hemangioendothelioma (KHE) because it presented with a bleeding diathesis thought to be Kasabach-Merritt phenomenon (KMP). Subsequently, the placental examination showed a neoplasm in the perivascular-subendothelial space of stem villi, initially thought to be myofibromatosis. Ultimately, a biopsy of the thigh mass showed IF with an NTRK3-ETV6 fusion. Subsequent FISH analysis of the placenta showed an ETV6 rearrangement confirming that it was also IF. Review of the laboratory studies suggests that disseminated intravascular coagulation may have been more likely than KMP, highlighting the difficulty in making this distinction in some cases. We believe this to be the first report of an IF presenting in a soft tissue site and the placenta, and discuss the possible mechanisms that could have allowed the IF in the leg to spread to the placenta.

Wee1 kinase inhibitor adavosertib with radiation in newly diagnosed diffuse intrinsic pontine glioma: A Children's Oncology Group phase I consortium study

Background

Children with diffuse intrinsic pontine gliomas (DIPG) have a dismal prognosis. Adavosertib (AZD1775) is an orally available, blood-brain barrier penetrant, Wee1 kinase inhibitor. Preclinical efficacy against DIPG is heightened by radiation induced replication stress.

Methods

Using a rolling six design, 7 adavosertib dose levels (DLs) (50 mg/m2 alternating weeks, 50 mg/m2 alternating with weeks of every other day, 50 mg/m2, then 95, 130, 160, 200 mg/m2) were assessed. Adavosertib was only given on days of cranial radiation therapy (CRT).The duration of CRT (54 Gy over 30 fractions; 6 weeks) constituted the dose limiting toxicity (DLT) period. Endpoints included tolerability, pharmacokinetics, overall survival (OS) and peripheral blood γH2AX levels as a marker of DNA damage.

Results

A total of 46 eligible patients with newly diagnosed DIPG [median (range) age 6 (3-21) years; 52% female] were enrolled. The recommend phase 2 dose (RP2D) of adavosertib was 200 mg/m2/d during days of CRT. Dose limiting toxicity included ALT elevation (n = 1, DL4) and neutropenia (n = 1, DL7). The mean Tmax, T1/2 and Clp on Day 1 were 2 h, 4.4 h, and 45.2 L/hr/m2, respectively. Modest accumulation of adavosertib was observed comparing day 5 versus day 1 AUC0-8h (accumulation ratio = 1.6). OS was 11.1 months (95% CI: 9.4, 12.5) and did not differ from historical control.

Conclusion

Adavosertib in combination with CRT is well tolerated in children with newly diagnosed DIPG, however, compared to historical controls, did not improve OS. These results can inform future trial design in children with high-risk cancer.

Development of an exosomal gene signature to detect residual disease in dogs with osteosarcoma using a novel xenograft platform and machine learning

Osteosarcoma has a guarded prognosis. A major hurdle in developing more effective osteosarcoma therapies is the lack of disease-specific biomarkers to predict risk, prognosis, or therapeutic response. Exosomes are secreted extracellular microvesicles emerging as powerful diagnostic tools. However, their clinical application is precluded by challenges in identifying disease-associated cargo from the vastly larger background of normal exosome cargo. We developed a method using canine osteosarcoma in mouse xenografts to distinguish tumor-derived from host-response exosomal messenger RNAs (mRNAs). The model allows for the identification of canine osteosarcoma-specific gene signatures by RNA sequencing and a species-differentiating bioinformatics pipeline. An osteosarcoma-associated signature consisting of five gene transcripts (SKA2, NEU1, PAF1, PSMG2, and NOB1) was validated in dogs with spontaneous osteosarcoma by real-time quantitative reverse transcription PCR (qRT-PCR), while a machine learning model assigned dogs into healthy or disease groups. Serum/plasma exosomes were isolated from 53 dogs in distinct clinical groups ("healthy", "osteosarcoma", "other bone tumor", or "non-neoplastic disease"). Pre-treatment samples from osteosarcoma cases were used as the training set, and a validation set from post-treatment samples was used for testing, classifying as "osteosarcoma detected" or "osteosarcoma-NOT detected". Dogs in a validation set whose post-treatment samples were classified as "osteosarcoma-NOT detected" had longer remissions, up to 15 months after treatment. In conclusion, we identified a gene signature predictive of molecular remissions with potential applications in the early detection and minimal residual disease settings. These results provide proof of concept for our discovery platform and its utilization in future studies to inform cancer risk, diagnosis, prognosis, and therapeutic response.

Abstract P162: Phase 1 trial of selinexor in children and adolescents with recurrent/refractory solid and CNS tumors (ADVL1414): A Children’s Oncology Group Phase 1 Consortium trial

Introduction: Selinexor is a first-in-class, central nervous system (CNS) penetrant, oral inhibitor of exportin 1 (XPO1), the sole nuclear exporter of many key tumor suppressors. Selinexor is FDA-approved for refractory multiple myeloma and DLBCL and has been evaluated in a phase 1 trial in children with leukemia. We report a phase 1 trial of selinexor in children and adolescents with recurrent CNS and solid tumors, including lymphoma (NCT02323880). Methods: A rolling-six design was used to evaluate selinexor (10 or 25 mg tablets) administered twice or once weekly during a 28-day cycle. Dose determination was based on protocol-defined dose limiting toxicity (DLT) using CTCAEv4 during cycle 1. First dose pharmacokinetics (PK) were performed. Results: 43 subjects were enrolled (17 males); median (range) age was 15 (6-20) years. 27 (63%) had CNS tumors, most commonly high-grade glioma (n=12); 16 (37%) had extracranial solid tumors. 42 were evaluable for DLT. At the starting dose (35 mg/m2/dose, twice weekly), no DLTs were observed in 6 subjects, however, 2 subjects had unexpected late myelosuppression delaying initiation of cycle 2. The dosing schedule was amended to twice weekly for 3 weeks followed by a 1 week break. 12 subjects received 35 mg/m2/dose; 4 experienced DLTs [grade 3 fatigue (n=2), grade 3 thrombocytopenia (n=1), or grade 3 ALT increase (n=1)]. The dose was de-escalated to 20 mg/m2/dose, 3 weeks on, 1 week off. 12 subjects enrolled; 3 experienced a DLT [grade 3 increased AST/ALT, acute reversible neurologic changes, or neutropenia (each n=1)]. At the 20 mg/m2 (n=12) and 35 mg/m2 (n=19) dose levels, respectively, the mean ± SD Cmax (ng/ml) was 324±116 and 535±174, and AUC (hr•ng/ml) was 3092 ± 842 and 5156 ± 1227. This was comparable to PK in adults receiving 35 and 50 mg/m2. Based on a desire to achieve a higher Cmax and avoid breaks in schedule, and emerging evidence for similar effectiveness with decreased toxicity in adults receiving continuous once weekly dosing, we evaluated a dosing schedule with once weekly dosing for all 4 weeks of each cycle. At the initial dose level (45 mg/m2 weekly), 2 of 6 subjects had DLTs [prolonged grade 2 thrombocytopenia or grade 3 seizure in a primary CNS tumor patient]. Six subjects received 35 mg/m2/dose once weekly; 1 DLT [grade 3 thrombocytopenia] was observed. Non-dose-limiting toxicity (Grade ≥2 occurring in &gt;10% of subjects during cycle 1) included lymphopenia, leukopenia, neutropenia, thrombocytopenia, anorexia, fatigue, hypophosphatemia, nausea, and vomiting. Subjects received a median (range) of 1 (1-9) cycle; 13 received 2-3 cycles, and 6 received 5-9 cycles. Conclusions: Selinexor-related toxicities were primarily hematological and gastrointestinal. The maximum tolerated dose (MTD) of selinexor in children and adolescents with recurrent solid and CNS tumors is 20 mg/m2/dose twice weekly for 3 weeks followed by one week off. On a continuous once weekly schedule, the MTD and recommended phase 2 starting dose of selinexor is 35 mg/m2/dose.

Citation Format: Adam L. Green, Charles G. Minard, Xiaowei Liu, Joel M. Reid, Kerice Pinkney, Stephan Voss, Marvin D. Nelson, Elizabeth Fox, Brenda J. Weigel, Julia Glade Bender. Phase 1 trial of selinexor in children and adolescents with recurrent/refractory solid and CNS tumors (ADVL1414): A Children’s Oncology Group Phase 1 Consortium trial [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P162.

A phase 1 study of prexasertib (LY2606368), a CHK1/2 inhibitor, in pediatric patients with recurrent or refractory solid tumors, including CNS tumors: A report from the Children's Oncology Group Pediatric Early Phase Clinical Trials Network (ADVL1515)

BACKGROUND

Prexasertib (LY2606368) is a novel, second-generation, selective dual inhibitor of checkpoint kinase proteins 1 (CHK1) and 2 (CHK2). We conducted a phase 1 trial of prexasertib to estimate the maximum-tolerated dose (MTD) and/or recommended phase 2 dose (RP2D), to define and describe the toxicities, and to characterize the pharmacokinetics (PK) of prexasertib in pediatric patients with recurrent or refractory solid and central nervous system (CNS) tumors.

METHODS

Prexasertib was administered intravenously (i.v.) on days 1 and 15 of a 28-day cycle. Four dose levels, 80, 100, 125, and 150 mg/m² , were evaluated using a rolling-six design. PK analysis was performed during cycle 1. Tumor tissue was examined for biomarkers (CHK1 and TP53) of prexasertib activity.

RESULTS

Thirty patients were enrolled; 25 were evaluable. The median age was 9.5 years (range: 2-20) and 21 (70%) were male. Twelve patients (40%) had solid tumors and 18 patients (60%) had CNS tumors. There were no cycle 1 or later dose-limiting toxicities. Common cycle 1, drug-related grade 3/4 toxicities (> 10% of patients) included neutropenia (100%), leukopenia (68%), thrombocytopenia (24%), lymphopenia (24%), and anemia (12%). There were no objective responses; best overall response was stable disease in three patients for five cycles (hepatocellular carcinoma), three cycles (ependymoma), and five cycles (undifferentiated sarcoma). The PK appeared dose proportional across the 80-150 mg/m² dose range.

CONCLUSIONS

Although the MTD of prexasertib was not defined by this study, 150 mg/m² administered i.v. on days 1 and 15 of a 28-day cycle was determined to be the RP2D.

A phase 1 study of entinostat in children and adolescents with recurrent or refractory solid tumors, including CNS tumors: Trial ADVL1513, Pediatric Early Phase-Clinical Trial Network (PEP-CTN)

BACKGROUND

Entinostat is an oral small molecule inhibitor of class I histone deacetylases (HDAC), which has not previously been evaluated in pediatrics. We conducted a phase I trial to determine the maximum tolerated dose/recommended phase 2 dose (MTD/RP2D), toxicity profile, pharmacokinetics (PK), and pharmacodynamics (PD) of entinostat in children with relapsed or refractory solid tumors including central nervous system (CNS) malignancies.

METHODS

A rolling six dose escalation design evaluated two dose levels. Entinostat oral tablet formulation was administered once per week, four doses per 28-day cycle. PK and PD studies were performed.

RESULTS

Twenty-one eligible patients' median (range) age was 14 years (6-20). Six subjects were treated at 3 mg/m² dose level and 15 were treated in 4 mg/m² dose level. The study included patients with CNS tumors (n = 12), sarcomas (n = 6), or other solid tumors (n = 3). Eight patients were not fully evaluable for toxicity due to progression of disease prior to receiving the required percentage of protocol therapy. No cycle one dose-limiting toxicity (DLT) was observed at either dose level. A three-fold higher area under the curve (AUC) was achieved in our cohort compared to adults using a similar dosing schedule. The PD studies showed increase in acetylated lysine in peripheral blood leukocytes at both doses.

CONCLUSIONS

Entinostat was well tolerated with no DLT observed. All patients experienced progression within the first two cycles, except one patient with ependymoma with stable disease. Based on PK and PD, the R2PD in pediatric patients with solid tumors is 4 mg/m² orally administered once weekly.

Activity of Crizotinib in Patients with ALK-Aberrant Relapsed/Refractory Neuroblastoma: A Children's Oncology Group Study (ADVL0912)

PURPOSE

Anaplastic lymphoma kinase (ALK) aberrations are a promising target for patients with neuroblastoma. We assessed the activity of first-generation ALK inhibitor crizotinib in patients with no known curative treatments and whose tumors harbored an activating ALK alteration.

PATIENTS AND METHODS

Twenty patients with relapsed/refractory ALK-positive neuroblastoma received crizotinib at the recommended phase II dose of 280 mg/m²/dose. A Simon two-stage design was used to evaluate the antitumor activity of crizotinib monotherapy. Response evaluation occurred after cycles 1, 3, 5, 7, and then every 3 cycles. Correlation of ALK status and response was a secondary aim of the study.

RESULTS

The objective response rate for patients with neuroblastoma was 15% [95% confidence interval (CI): 3.3%-34.3%]: two with partial responses and 1 with a complete response. All three patients had a somatic ALK Arg1275Gln mutation, the most common ALK hotspot mutation observed in neuroblastoma and the only mutation predicted to be sensitive to ALK inhibition with crizotinib. Two patients had prolonged stable disease (10 and 13 cycles, respectively); both harbored an ALK Arg1275Gln mutation. Three patients with ALK Phe1174Leu mutations progressed during cycle 1 of therapy, and one patient with an ALK Phe1174Val received three cycles before disease progression. The two patients with ALK amplification had no response. The most common adverse event was a decrease in neutrophil count.

CONCLUSIONS

Despite limited activity seen in this trial, we conclude that this is more likely due to an inability to reach the higher concentrations of crizotinib needed to overcome the competing ATP affinity.See related commentary by Schulte and Eggert, p. 3507.

Phase 1 trial of olaratumab monotherapy and in combination with chemotherapy in pediatric patients with relapsed/refractory solid and central nervous system tumors

Olaratumab is a monoclonal antibody that specifically binds to platelet-derived growth factor receptor alpha (PDGFRα) and blocks receptor activation. We conducted a phase 1 trial to evaluate the safety of olaratumab and determine a recommended dose in combination with three different chemotherapy regimens in children. Patients <18 years with relapsed/refractory solid or central nervous system tumors were enrolled to two dose levels of olaratumab. Patients received olaratumab monotherapy at 15 mg/kg (Part A) or 20 mg/kg (Part B) on Days 1 and 8 of the first 21-day cycle, followed by olaratumab combined with standard fixed doses of chemotherapy with doxorubicin, vincristine/irinotecan, or high-dose ifosfamide by investigator choice for subsequent 21-day cycles. In Part C, patients received olaratumab 20 mg/kg plus assigned chemotherapy for all cycles. Parts A-C enrolled 68 patients across three chemotherapy treatment arms; olaratumab in combination with doxorubicin (N = 16), vincristine/irinotecan (N = 26), or ifosfamide (N = 26). Three dose-limiting toxicities (DLTs) occurred during olaratumab monotherapy (at 15 mg/kg, grade [G] 4 alanine aminotransferase [ALT]; at 20 mg/kg, G3 lung infection and G3 gamma-glutamyl transferase). One DLT occurred during vincristine/irinotecan with olaratumab 20 mg/kg therapy (G3 ALT). Treatment-emergent adverse events ≥G3 in >25% of patients included neutropenia, anemia, leukopenia, lymphopenia, and thrombocytopenia. Pharmacokinetic profiles of olaratumab with chemotherapy were within the projected range based on adult data. There was one complete response (rhabdomyosarcoma [Part B vincristine/irinotecan arm]) and three partial responses (two rhabdomyosarcoma [Part A doxorubicin arm and Part C doxorubicin arm]; one pineoblastoma [Part B vincristine/irinotecan arm]). Olaratumab was tolerable and safely administered in combination with chemotherapy regimens commonly used in children and adolescents.

Metabolic response as assessed by 18 F-fluorodeoxyglucose positron emission tomography-computed tomography does not predict outcome in patients with intermediate- or high-risk rhabdomyosarcoma: A report from the Children's Oncology Group Soft Tissue Sarcoma Committee

BACKGROUND

Strategies to optimize management in rhabdomyosarcoma (RMS) include risk stratification to assign therapy aiming to minimize treatment morbidity yet improve outcomes. This analysis evaluated the relationship between complete metabolic response (CMR) as assessed by ¹⁸ F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET) imaging and event-free survival (EFS) in intermediate-risk (IR) and high-risk (HR) RMS patients.

METHODS

FDG-PET imaging characteristics, including assessment of CMR and maximum standard uptake values (SUVmax) of the primary tumor, were evaluated by central review. Institutional reports of SUVmax were used when SUVmax values could not be determined by central review. One hundred and thirty IR and 105 HR patients had FDG-PET scans submitted for central review or had SUVmax data available from institutional report at any time point. A Cox proportional hazards regression model was used to evaluate the relationship between these parameters and EFS.

RESULTS

SUVmax at study entry did not correlate with EFS for IR (p = 0.32) or HR (p = 0.86) patients. Compared to patients who did not achieve a CMR, EFS was not superior for IR patients who achieved a CMR at weeks 4 (p = 0.66) or 15 (p = 0.46), nor for HR patients who achieved CMR at week 6 (p = 0.75) or 19 (p = 0.28). Change in SUVmax at week 4 (p = 0.21) or 15 (p = 0.91) for IR patients or at week 6 (p = 0.75) or 19 (p = 0.61) for HR patients did not correlate with EFS.

CONCLUSION

Based on these data, FDG-PET does not appear to predict EFS in IR or HR-RMS. It remains to be determined whether FDG-PET has a role in predicting survival outcomes in other RMS subpopulations.

Racial and Ethnic Differences in Sarcoma Incidence Are Independent of Census-Tract Socioeconomic Status

BACKGROUND

Epidemiologic analyses of sarcoma are limited by the heterogeneity and rarity of the disease. Utilizing population-based surveillance data enabled us to evaluate the contribution of census tract-level socioeconomic status (CT-SES) and race/ethnicity on sarcoma incidence rates.

METHODS

We utilized the Surveillance, Epidemiology, and End Results program to evaluate associations between CT-SES and race/ethnicity on the incidence rates of sarcoma. Incidence rate ratios and 99% confidence intervals were estimated from quasi-Poisson models. All models were stratified by broad age groups (pediatric: <20 years, adult: 20-65 years, older adult: 65+ years) and adjusted for sex, age, and year of diagnosis. Within each age group, we conducted analyses stratified by somatic genome (fusion-positive and fusion-negative sarcomas) and for subtypes with >200 total cases. A P value less than 0.01 was considered statistically significant.

RESULTS

We included 55,415 sarcoma cases in 35 sarcoma subtype-age group combinations. Increasing CT-SES was statistically significantly associated with 11 subtype-age group combinations, primarily in the older age group strata (8 subtypes), whereas malignant peripheral nerve sheath tumors in adults were associated with decreasing CT-SES. Nearly every sarcoma subtype-age group combination displayed racial/ethnic disparities in incidence that were independent of CT-SES.

CONCLUSIONS

We found race/ethnicity to be more frequently associated with sarcoma incidence than CT-SES. Our findings suggest that genetic variation associated with ancestry may play a stronger role than area-level SES-related factors in the etiology of sarcoma.

IMPACT

These findings provide direction for future etiologic studies of sarcomas.

Safety, tolerability and pharmacokinetics of crizotinib in combination with cytotoxic chemotherapy for pediatric patients with refractory solid tumors or anaplastic large cell lymphoma (ALCL): a Children's Oncology Group phase 1 consortium study (ADVL1212)

PURPOSE

This phase 1 study aimed to determine the safety, tolerability and recommended phase 2 dose (RP2D) of crizotinib in combination with cytotoxic chemotherapy for children with refractory solid tumors and ALCL.

METHODS

Pediatric patients with treatment refractory solid tumors or ALCL were eligible. Using a 3 + 3 design, crizotinib was escalated in three dose levels: 165, 215, or 280 mg/m²/dose BID. In Part A, patients received crizotinib oral solution (OS) in combination with topotecan and cyclophosphamide (topo/cyclo); in Part B, crizotinib OS was administered with vincristine and doxorubicin (vcr/dox). In Parts C and D, patients received topo/cyclo in combination with either crizotinib-formulated capsules (FC) or microspheres (cMS), respectively. Crizotinib pharmacokinetic evaluation was required.

RESULTS

Forty-four eligible patients were enrolled, 39 were evaluable for toxicity. Parts A and B were terminated due to concerns regarding palatability and tolerability of the OS. In Part C, crizotinib, FC 215 mg/m²/dose BID, in combination with topo/cyclo was tolerated. In Part D, the maximum tolerated dose (MTD) was exceeded at 165 mg/m²/dose of crizotinib cMS. Pharmacokinetics of crizotinib in combination with chemotherapy was similar to single-agent crizotinib and exposures were not formulation dependent.

CONCLUSIONS

The RP2D of crizotinib FCs in combination with cyclophosphamide and topotecan was 215 mg/m²/dose BID. The oral solution of crizotinib was not palatable in this patient population. Crizotinib cMS was palatable; however, patients experienced increased toxicity that was not explained by the relative bioavailability or exposure and warrants further investigation.

CLINICAL TRIAL REGISTRY

The trial is registered as NCT01606878 at Clinicaltrials.gov.

Safety and efficacy of gamma-secretase inhibitor nirogacestat (PF-03084014) in desmoid tumor: Report of four pediatric/young adult cases

Systemic therapy for pediatric desmoid tumors has been challenged by a lack of high-quality clinical evidence and potential adverse effects. The gamma-secretase inhibitor nirogacestat has shown promising efficacy in adults. We report four cases of pediatric and young adult desmoid tumor patients (three with familial adenomatous polyposis [FAP] syndrome) who received nirogacestat on compassionate use. After a median of 13.5 months (range 6-18), three had durable benefit: a complete response (Case 1); a partial response (Case 2); stable disease (Case 3). The fourth had disease progression after a partial response. No patient experienced grade 3 or 4 adverse events.

ADVL1522: A phase 2 study of lorvotuzumab mertansine (IMGN901) in children with relapsed or refractory wilms tumor, rhabdomyosarcoma, neuroblastoma, pleuropulmonary blastoma, malignant peripheral nerve sheath tumor, or synovial sarcoma-A Children's Oncology Group study

BACKGROUND

Lorvotuzumab mertansine (IMGN901) is an antibody-drug conjugate linking an antimitotic agent (DM1) to an anti-CD56 antibody (lorvotuzumab). Preclinical efficacy has been noted in Wilms tumor, rhabdomyosarcoma, and neuroblastoma. Synovial sarcoma, malignant peripheral nerve sheath tumor (MPNST), and pleuropulmonary blastoma also express CD56. A phase 2 trial of lorvotuzumab mertansine was conducted to assess its efficacy, recommended phase 2 dose, and toxicities.

METHODS

Eligible patients had relapsed after or progressed on standard therapy for their tumor type. Lorvotuzumab mertansine (110 mg/m² per dose) was administered at the adult recommended phase 2 dose intravenously on days 1 and 8 of 21-day cycles. Dexamethasone premedication was used. Pharmacokinetic samples, peripheral blood CD56-positive cell counts, and tumor CD56 expression were assessed.

RESULTS

Sixty-two patients enrolled. The median age was 14.3 years (range, 2.8-29.9 years); 35 were male. Diagnoses included Wilms tumor (n = 17), rhabdomyosarcoma (n = 17), neuroblastoma (n = 12), synovial sarcoma (n = 10), MPNST (n = 5), and pleuropulmonary blastoma (n = 1). Five patients experienced 9 dose-limiting toxicities: hyperglycemia (n = 1), colonic fistula (n = 1) with perforation (n = 1), nausea (n = 1) with vomiting (n = 1), increased alanine aminotransferase in cycle 1 (n = 2), and increased alanine aminotransferase in cycle 2 (n = 1) with increased aspartate aminotransferase (n = 1). Non-dose-limiting toxicities (grade 3 or higher) attributed to lorvotuzumab mertansine were rare. The median values of the maximum concentration, half-life, and area under the curve from zero to infinity for DM1 were 0.87 µg/mL, 35 hours, and 27.9 µg/mL h, respectively. Peripheral blood CD56+ leukocytes decreased by 71.9% on day 8. One patient with rhabdomyosarcoma had a partial response, and 1 patient with synovial sarcoma achieved a delayed complete response.

CONCLUSIONS

Lorvotuzumab mertansine (110 mg/m² ) is tolerated in children at the adult recommended phase 2 dose; clinical activity is limited.

Associations of Socioeconomic Status, Public vs Private Insurance, and Race/Ethnicity With Metastatic Sarcoma at Diagnosis

IMPORTANCE

Approximately 10% to 30% of patients with sarcoma present with detectable metastases at diagnosis. However, the extent to which presentation with metastases is due to delayed diagnosis vs other factors remains unclear.

OBJECTIVE

To evaluate whether socioeconomic status, insurance status, or race/ethnicity were associated with the presence of metastases at diagnosis of sarcoma.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the population-based Surveillance, Epidemiology, and End Results program. Adult and pediatric patients with an initial diagnosis of soft-tissue and bone sarcoma between 2001 and 2015 were stratified by age group (pediatric, <20 years; adult, 20-65 years; older adult, >65 years) and sarcoma subtype. Statistical analyses were performed between August 2019 and January 2020.

EXPOSURES

Surveillance, Epidemiology, and End Results Census tract-level socioeconomic status index, insurance status, and race/ethnicity.

MAIN OUTCOMES AND MEASURES

The odds of presenting with metastases at diagnosis were calculated.

RESULTS

A total of 47 337 patients with first primary malignant sarcoma were included (24 343 male patients [51.4%]), with 29 975 non-Hispanic White patients (63.3%), 5673 non-Hispanic Black patients (12.0%), 7504 Hispanic patients (15.8%), and 4185 American Indian-Alaskan Native and Asian Pacific Islander patients (8.8%). Liposarcoma in adults was the only subtype and age group combination that demonstrated a significant trend in incidence across socioeconomic status levels (odds ratio, 0.85; 99% CI, 0.76-0.96; P = .001). However, compared with having non-Medicaid insurance, having Medicaid or no insurance in adults was associated with an increased odds of metastases at diagnosis for 6 of the 8 sarcoma subtypes evaluated; osteosarcoma and Ewing sarcoma were the only 2 subtypes in adults for which metastases were not associated with insurance status. In addition, there was an increased risk of presenting with metastases among non-Hispanic Black adults diagnosed with leiomyosarcoma (odds ratio, 1.87; 99% CI, 1.41-2.48) and unclassified sarcomas (odds ratio, 1.65; 99% CI, 1.01-2.67) compared with non-Hispanic White adults that was independent of socioeconomic and insurance status.

CONCLUSIONS AND RELEVANCE

These findings suggest that delayed access to care is associated with advanced stage at diagnosis for several soft-tissue sarcoma subtypes in adults, whereas other factors may be associated with the metastatic progression of osteosarcoma and Ewing sarcoma, as well as the racial disparities observed with metastatic leiomyosarcoma and unclassified sarcomas.

Nivolumab in children and young adults with relapsed or refractory solid tumours or lymphoma (ADVL1412): a multicentre, open-label, single-arm, phase 1-2 trial

BACKGROUND

Immune checkpoint inhibitors targeting PD-1 have shown clinical benefit in adults with cancer, but data on these drugs in children are scarce. We did a phase 1-2 study of nivolumab, a PD-1 blocking monoclonal antibody, to determine its safety, pharmacokinetics, and antitumour activity in children and young adults with recurrent or refractory non-CNS solid tumours or lymphoma.

METHODS

We did a multicentre, open-label, single-arm, dose-confirmation and dose-expansion, phase 1-2 trial in 23 hospitals in the USA. Eligible patients for part A (dose-confirmation phase) of the study were aged 1-18 years with solid tumours with measurable or evaluable disease (by Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1) regardless of histology. Eligible patients for part B (dose-expansion phase) were aged 1-30 years with measurable disease (by RECIST criteria) in the following disease cohorts: rhabdomyosarcoma, Ewing sarcoma, osteosarcoma, neuroblastoma, Hodgkin lymphoma, non-Hodgkin lymphoma, and melanoma. Patients in part A and were given nivolumab 3 mg/kg intravenously over 60 min on days 1 and 15 of a 28-day cycle in a rolling 6 study design with de-escalation upon dose-limiting toxicities to establish the recommended phase 2 dose. Patients in part B were given the recommended phase 2 dose. The primary outcomes were the tolerability, systemic exposure, maximum tolerated dose, and the antitumour activity of nivolumab at the adult recommended dose in children and young adults. This trial is registered with ClinicalTrials.gov, NCT02304458, with follow-up ongoing and is closed to new participants.

FINDINGS

85 patients were enrolled between Feb 22, 2015, and Dec 31, 2018, and 75 patients were fully evaluable for toxicity. Median follow-up was 30 days (IQR 27-83). In part A, 13 patients were enrolled and 12 were evaluable for toxicity. There were no dose de-escalations or dose-limiting toxicities and nivolumab 3 mg/kg was confirmed as the paediatric recommended phase 2. 72 patients were enrolled in part B and 63 were evaluable for toxicity. Five (7%) patients in part B had dose-limiting toxicities. The most common overall toxicity was anaemia (35 [47%] of 75 patients; five patients had grade 3 or grade 4) and non-haematological toxicity was fatigue (28 [37%] patients; none had grade 3 or grade 4). Responses were observed in patients with lymphoma (three [30%] of ten with Hodgkin lymphoma and one [10%] of ten with non-Hodgkin lymphoma; all responders had PD-L1 expression). Objective responses were not observed in other tumour types.

INTERPRETATION

Nivolumab was safe and well tolerated in children and young adults and showed clinical activity in lymphoma. Nivolumab showed no significant single-agent activity in the common paediatric solid tumours. This study defines the recommended phase 2 dose and establishes a favourable safety profile for nivolumab in children and young adults, which can serve as the basis for its potential study in combinatorial regimens for childhood cancer.

FUNDING

Bristol-Myers Squibb, Children's Oncology Group, National Institutes of Health, Cookies for Kids Cancer Foundation.

Phase 1/2 trial of talazoparib in combination with temozolomide in children and adolescents with refractory/recurrent solid tumors including Ewing sarcoma: A Children's Oncology Group Phase 1 Consortium study (ADVL1411)

PURPOSE

We conducted a phase 1/2 trial of the poly(ADP-ribose) polymerase 1/2 inhibitor talazoparib in combination with low-dose temozolomide (TMZ) to determine the dose-limiting toxicities (DLTs), recommended phase 2 dose (RP2D), and pharmacokinetics of this combination in children with recurrent/refractory solid tumors; and to explore clinical activity in Ewing sarcoma (EWS) (NCT02116777).

METHODS

Talazoparib (400-600 µg/m² /dose, maximum daily dose 800-1000 µg) was administered q.d. or b.i.d. orally on day 1 followed by q.d. dosing concomitant with q.d. dosing of oral TMZ (20-55 mg/m² /day) on days 2 to 6, every 28 days.

RESULTS

Forty patients, aged 4 to 25 years, were enrolled. Talazoparib was increased to 600 µg/m² /dose b.i.d. on day 1, and q.d. thereafter, with 20 mg/m² /day of TMZ, without DLTs. TMZ was subsequently increased, during which dose-limiting neutropenia and thrombocytopenia occurred in two of three subjects at 55 mg/m² /day, two of six subjects at 40 mg/m² /day, and one of six subjects at 30 mg/m² /day. During dose-finding, two of five EWS and four of 25 non-EWS subjects experienced prolonged stable disease (SD), and one subject with malignant glioma experienced a partial response. In phase 2, 0 of 10 EWS subjects experienced an objective response; two experienced prolonged SD.

CONCLUSIONS

Talazoparib and low-dose TMZ are tolerated in children with recurrent/refractory solid tumors. Reversible neutropenia and thrombocytopenia were dose limiting. The RP2D is talazoparib 600 µg/m² b.i.d. on day 1 followed by 600 µg/m² q.d. on days 2 to 6 (daily maximum 1000 µg) in combination with temozolomide 30 mg/m² /day on days 2 to 6. Antitumor activity was not observed in EWS, and limited antitumor activity was observed in central nervous system tumors.

Phase I Clinical Trial of the Wee1 Inhibitor Adavosertib (AZD1775) with Irinotecan in Children with Relapsed Solid Tumors: A COG Phase I Consortium Report (ADVL1312)

PURPOSE

Adavosertib (AZD1775), an inhibitor of WEE1 kinase, potentiates replicative stress induced by oncogenes or chemotherapy. Antitumor activity of adavosertib has been demonstrated in preclinical models of pediatric cancer. This phase I trial was performed to define dose-limiting toxicities (DLT), recommended phase II dose (RP2D), and pharmacokinetics of adavosertib in combination with irinotecan in children and adolescents with relapsed or refractory solid tumors or primary central nervous system tumors.

PATIENTS AND METHODS

Using a 3+3 escalation design, five dose cohorts of the combination of adavosertib and irinotecan (50/70; 65/70; 65/90; 85/90; 110/90 mg/m²/day) delivered on days 1-5 of a 21-day cycle were studied. Pharmacokinetics and analysis of peripheral blood γH2AX was performed.

RESULTS

Thirty-seven patients were enrolled; 27 were evaluable. The median (range) age was 14 (2-20) years. Twenty-five (93%) received prior chemotherapy (median, three regimens) and 21 (78%) received prior radiotherapy. Eleven patients had a primary central nervous system (CNS) malignancy. Common toxicities were hematologic and gastrointestinal. Two patients receiving adavosertib (110 mg/m²) in combination with irinotecan (90 mg/m²) experienced dose-limiting grade 3 dehydration. A patient with Ewing sarcoma had a confirmed partial response and 2 patients (ependymoma and neuroblastoma) had prolonged stable disease (≥ 6 cycles). Pharmacokinetics of adavosertib were variable but generally dose proportional and clearance was lower in younger patients.

CONCLUSIONS

Adavosertib (85 mg/m²) in combination with irinotecan (90 mg/m²) administered orally for 5 days was the MTD in children and adolescents with solid and CNS tumors.

Phase II trial of the glycoprotein non-metastatic B-targeted antibody-drug conjugate, glembatumumab vedotin (CDX-011), in recurrent osteosarcoma AOST1521: A report from the Children's Oncology Group

BACKGROUND

The prognosis is poor for children and adolescents with recurrent osteosarcoma (OS). Glycoprotein non-metastatic B (gpNMB) is a glycoprotein highly expressed in OS cells. We conducted a phase II study of glembatumumab vedotin (GV), a fully human IgG2 monoclonal antibody (CR011) against gpNMB conjugated to the microtubule inhibitor, monomethyl auristatin E.

PATIENTS AND METHODS

Patients aged ≥12 years and <50 years with relapsed or refractory OS were eligible. GV 1.9 mg/kg/dose was administered on day 1 of each 21 day cycle. Pharmacokinetics were mandatory in patients aged <15 years. gpNMB expression was measured by immunohistochemistry. The primary end-point was disease control at 4 months and Response Evaluation Criteria in Solid Tumours response. A 2-stage design was used to determine efficacy.

RESULTS

Twenty-two patients were enrolled, and all were evaluable for response. Antibody-drug conjugate levels were detectable in patients, although small numbers limit comparison to adult data. The toxicities observed were similar to the previous studies with GV. The most common grade III adverse event was rash. One death from end organ failure occurred possibly related to GV. Of the 22 patients, one patient had a partial response, and two had stable disease. There was no correlation between gpNMB expression and response to GV.

CONCLUSIONS

GV was well tolerated in this population. Although there was some antitumour activity, the extent of disease control in stage I did not meet the level required to proceed to stage II.

TRIAL REGISTRATION NUMBERS

NCT02487979.

A Phase II Study of Alisertib in Children with Recurrent/Refractory Solid Tumors or Leukemia: Children's Oncology Group Phase I and Pilot Consortium (ADVL0921)

PURPOSE

Aurora A kinase (AAK) plays an integral role in mitotic entry, DNA damage checkpoint recovery, and centrosome and spindle maturation. Alisertib (MLN8237) is a potent and selective AAK inhibitor. In pediatric preclinical models, antitumor activity was observed in neuroblastoma, acute lymphoblastic leukemia, and sarcoma xenografts. We conducted a phase 2 trial of alisertib in pediatric patients with refractory or recurrent solid tumors or acute leukemias (NCT01154816).

PATIENTS AND METHODS

Alisertib (80 mg/m2/dose) was administered orally, daily for 7 days every 21 days. Pharmacogenomic (PG) evaluation for polymorphisms in the AURK gene and drug metabolizing enzymes (UGT1A1*28), and plasma pharmacokinetic studies (PK) were performed. Using a 2-stage design, patients were enrolled to 12 disease strata (10 solid tumor and 2 acute leukemia). Response was assessed after cycle 1, then every other cycle.

RESULTS

A total of 139 children and adolescents (median age, 10 years) were enrolled, 137 were evaluable for response. Five objective responses were observed (2 complete responses and 3 partial responses). The most frequent toxicity was myelosuppression. The median alisertib trough concentration on day 4 was 1.3 μmol/L, exceeding the 1 μmol/L target trough concentration in 67% of patients. No correlations between PG or PK and toxicity were observed.

CONCLUSIONS

Despite alisertib activity in pediatric xenograft models and cogent pharmacokinetic-pharmacodynamic relationships in preclinical models and adults, the objective response rate in children and adolescents receiving single-agent alisertib was less than 5%.

Identification of aggressive Gardner syndrome phenotype associated with a de novo APC variant, c.4666dup

Gardner syndrome describes a variant phenotype of familial adenomatous polyposis (FAP), primarily characterized by extracolonic lesions including osteomas, dental abnormalities, epidermal cysts, and soft tissue tumors. We describe a 2-yr-old boy presenting with a 2-cm soft tissue mass of the forehead. Pathologic evaluation revealed a nuchal-type/Gardner-associated fibroma. Sequencing of the APC gene revealed a pathologic variant c.4666dupA. Parental sequencing of both blood and buccal tissue supported the de novo occurrence of this pathologic variant. Further imaging revealed a number of additional lesions including a large lumbar paraspinal desmoid, a 1-cm palpable lesion posterior to the left knee, firm lesions on bilateral heels, and multiple subdermal lesions. Colonoscopy was negative. This case illustrates a genetic variant of Gardner syndrome resulting in an aggressive early childhood phenotype and highlights the need for an individualized approach to treatment.

A study of axitinib, a VEGF receptor tyrosine kinase inhibitor, in children and adolescents with recurrent or refractory solid tumors: A Children's Oncology Group phase 1 and pilot consortium trial (ADVL1315)

BACKGROUND

Axitinib is an oral small molecule that inhibits receptor tyrosine kinases vascular endothelial growth factor receptors 1 to 3. A phase 1 and pharmacokinetic (PK) trial evaluating axitinib was conducted in children with refractory solid tumors.

METHODS

Axitinib was administered orally twice daily in continuous 28-day cycles. Dose levels (2.4 mg/m² /dose and 3.2 mg/m² /dose) were evaluated using a rolling 6 design. Serial PKs (cycle 1, days 1 and 8) and exploratory biomarkers were analyzed.

RESULTS

A total of 19 patients were enrolled; 1 patient was ineligible due to inadequate time having elapsed from prior therapy. The median age of the patients was 13.5 years (range, 5-17 years). Two of 5 patients who were treated at dose level 2 experienced dose-limiting toxicities (palmar-plantar erythryodysesthesia syndrome in 1 patient and intratumoral hemorrhage in 1 patient). Frequent (>20%) grade 1 to 2 toxicities during cycle 1 included anemia, anorexia, fatigue, diarrhea, nausea, and hypertension. Nonhematological toxicities of grade ≥3 in subsequent cycles included hypertension and elevated serum lipase. PK analysis demonstrated variability in axitinib exposure, the median time to peak plasma concentration was 2 hours, and the half-life ranged from 0.7 to 5.2 hours. Exposure and dose were not found to be significantly associated with hypertension. Five patients achieved stable disease for ≤6 cycles as their best response, including patients with malignant peripheral nerve sheath tumor (1 patient), Ewing sarcoma (1 patient), hepatocellular carcinoma (1 patient), and osteosarcoma (2 patients). One patient with alveolar soft part sarcoma achieved a partial response. Kidney injury biomarkers were found to be elevated at baseline; no trends were identified.

CONCLUSIONS

In children with refractory solid tumors, the maximum tolerated and recommended dose of axitinib appears to be 2.4 mg/m² /dose, which provides PK exposures similar to those of adults.

The addition of cixutumumab or temozolomide to intensive multiagent chemotherapy is feasible but does not improve outcome for patients with metastatic rhabdomyosarcoma: A report from the Children's Oncology Group

BACKGROUND

The outcome for patients with metastatic rhabdomyosarcoma (RMS) remains poor. A previous Children's Oncology Group (COG) study (ARST0431) for patients with metastatic RMS produced no improvement in outcome using multiple cytotoxic agents in a dose-intensive manner. The authors report results from the subsequent COG study (ARST08P1), which evaluated the feasibility and efficacy of adding cixutumumab (insulin-like growth factor-1 monoclonal antibody) or temozolomide to the ARST0431 intensive chemotherapy backbone.

METHODS

Two nonrandomized pilot studies were conducted in patients with metastatic RMS, initially to determine feasibility, and both pilots were expanded to assess efficacy. All patients received 54 weeks of chemotherapy, including vincristine/irinotecan, interval-compressed vincristine/doxorubicin/cyclophosphamide alternating with ifosfamide/etoposide, and vincristine/dactinomycin/cyclophosphamide. In pilot 1, patients received intravenous cixutumumab (3, 6, or 9 mg/kg) once weekly throughout therapy. In pilot 2, patients received oral temozolomide (100 mg/m² ) daily for 5 days with irinotecan. All patients received radiation to the primary tumor and to metastatic sites.

RESULTS

One hundred sixty-eight eligible patients were enrolled (97 on pilot 1 and 71 on pilot 2). Most patients were aged ≥10 years (73%), with alveolar histology (70%), and had bone and/or bone marrow metastases (59%). Toxicities observed in each pilot were similar to those reported on ARST0431. With a median follow-up of 2.9 years, the 3-year event-free survival rate was 16% (95% confidence interval, 7%-25%) with cixutumumab and 18% (95% confidence interval, 2%-35%) with temozolomide.

CONCLUSIONS

The addition of cixutumumab or temozolomide to intensive multiagent chemotherapy for metastatic RMS was safe and feasible. Neither agent improved outcome compared with the same chemotherapy that was used on ARST0431.

Brentuximab vedotin with gemcitabine for paediatric and young adult patients with relapsed or refractory Hodgkin's lymphoma (AHOD1221): a Children's Oncology Group, multicentre single-arm, phase 1-2 trial

BACKGROUND

Patients with primary refractory Hodgkin's lymphoma or early relapse have a poor prognosis. Although many salvage regimens have been developed, there is no standard of care. Brentuximab vedotin and gemcitabine have been shown to be active in patients with relapsed or refractory Hodgkin's lymphoma when used as monotherapy, and each has been successfully used in combination with other agents. Preclinical data suggest that brentuximab vedotin can sensitise lymphoma cells to gemcitabine, supporting the use of the combination. We aimed to define the safety and efficacy of brentuximab vedotin with gemcitabine in children and young adults with primary refractory Hodgkin's lymphoma or early relapse.

METHODS

In this Children's Oncology Group, multicentre, single-arm, phase 1-2 trial, we recruited patients with Hodgkin's lymphoma from hospitals across the USA and Canada. Eligible patients were aged younger than 30 years, had no previous brentuximab vedotin exposure, and had primary refractory disease or relapse of less than 1 year from completion of initial treatment. Each 21-day cycle consisted of 1000 mg/m2 intravenous gemcitabine on days 1 and 8 and intravenous brentuximab vedotin on day 1 at 1·4 mg/kg or 1·8 mg/kg. The primary objectives were to establish the recommended phase 2 dose of brentuximab vedotin in this combination, the safety of the combination, and the proportion of patients who achieved a complete response among those treated at the recommended phase 2 level, within four cycles of treatment. This trial is registered with ClinicalTrials.gov, number NCT01780662.

FINDINGS

Between Feb 5, 2013, and Aug 19, 2016, 46 patients were enrolled, including one who was found to be ineligible, in the two phases of the study. The recommended phase 2 dose of brentuximab vedotin was 1·8 mg/kg in combination with gemcitabine 1000 mg/m2. 24 (57%) of 42 evaluable patients (95% CI 41-72) given this dose level had a complete response within the first four cycles of treatment. Four (31%) of 13 patients with a partial response or stable disease had all target lesions with Deauville scores of 3 or less after cycle 4. By modern response criteria, these were also complete responses (total number with complete response 28 [67%] of 42 [95% CI 51-80]). The most common grade 3-4 adverse events in all 42 participants treated at the recommended phase 2 dose were neutropenia (15 [36%]), rash (15 [36%]), transaminitis (9 [21%]), and pruritus (4 [10%]). There were no treatment-related deaths.

INTERPRETATION

Brentuximab vedotin with gemcitabine is a safe combination treatment with a tolerable toxicity profile for patients with primary refractory Hodgkin's lymphoma or high-risk relapse. The preliminary activity of this combination shown in this trial warrants further investigation in randomised controlled trials.

FUNDING

National Institutes of Health and the St. Baldrick's Foundation.

A phase 1 study of eribulin mesylate (E7389), a novel microtubule-targeting chemotherapeutic agent, in children with refractory or recurrent solid tumors: A Children's Oncology Group Phase 1 Consortium study (ADVL1314)

BACKGROUND

Eribulin mesylate is a novel anticancer agent that inhibits microtubule growth, without effects on shortening, and promotes nonproductive tubulin aggregate formation. We performed a phase 1 trial to determine the dose-limiting toxicities (DLTs), maximum tolerated or recommended phase 2 dose (MTD/RP2D), and pharmacokinetics (PK) of eribulin in children with refractory or recurrent solid (excluding central nervous system) tumors.

METHODS

Eribulin was administered intravenously on days 1 and 8 in 21-day cycles. Three dose levels (1.1, 1.4, and 1.8 mg/m2 /dose) were evaluated using the rolling six design with additional patients enrolled into a PK expansion cohort at the MTD. PK samples were obtained following the day 1, cycle 1 dose.

RESULTS

Twenty-three patients, ages 3-17 (median 14) years were enrolled; 20 were evaluable for toxicity. DLTs occurred in 0/6 and 1/6 subjects at the 1.1 and 1.4 mg/m2 /dose, respectively. One subject at the 1.4 mg/m2 /dose had grade 4 neutropenia and grade 3 fatigue. At the 1.8 mg/m2 /dose, 2/5 subjects experienced dose-limiting (grade 4) neutropenia. Grade 3/4 non-DLTs included lymphopenia and hypokalemia, while low-grade toxicities included anorexia and nausea. No episodes of grade > 2 corrected QT interval prolongation or peripheral neuropathy were reported. Eribulin pharmacokinetic parameters were highly variable; the median elimination half-life was 39.6 (range 24.2-96.4) hr. A partial response was observed in one patient (Ewing sarcoma).

CONCLUSIONS

Eribulin was well tolerated in children with refractory or recurrent solid tumors with neutropenia identified as the primary DLT. The RP2D of eribulin is 1.4 mg/m2 /dose on days 1 and 8 of a 21-day cycle.

A phase 1 study of cabozantinib in children and adolescents with recurrent or refractory solid tumors, including CNS tumors: Trial ADVL1211, a report from the Children's Oncology Group

BACKGROUND

We conducted a phase 1 trial to determine the maximum tolerated dose (MTD), toxicity profile, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary activity of cabozantinib in children with refractory or relapsed solid tumors.

METHODS

Patients received cabozantinib tablets on a continuous dosing schedule in a rolling-six escalating phase 1 trial design. PK and PD studies were performed.

RESULTS

Forty-one patients, median (range) age 13 (4-18) years, received cabozantinib to achieve a weekly cumulative dose equivalent to 30 (n = 6), 40 (n = 23). or 55 (n = 12) mg/m² /day. At 40 mg/m² /d, dose-limiting toxicities (DLTs) were palmar-plantar erythrodysesthesia syndrome, mucositis, and elevated alanine aminotransferase, lipase, and bilirubin. At 55 mg/m² /d, hypertension, reversible posterior leukoencephalopathy syndrome, headache, fatigue, and proteinuria were DLTs. Frequent non-DLTs included diarrhea, hypothyroidism, fatigue, nausea, vomiting, elevated hepatic transaminases, and proteinuria. In subsequent cycles, DLTs occurred at all dose levels. Across all dose levels, the steady-state exposure and peak cabozantinib concentrations were similar. Four patients experienced a confirmed partial response: medullary thyroid cancer (MTC; n = 2), Wilms tumor, and clear cell sarcoma. Stable disease (>6 cycles) was seen in seven patients (MTC [n = 2], Ewing sarcoma, synovial sarcoma, alveolar soft part sarcoma, paraganglioma, and ependymoma).

CONCLUSIONS

A protocol-defined MTD was not reached; DLTs and dose reductions for toxicity occurred in the first and subsequent cycles at all dose levels. Based on the toxicity profile, pharmacokinetics, and responses, the recommended dose of cabozantinib in pediatric patients with refractory solid tumors is 40 mg/m² /day. A phase 2 study of cabozantinib is being conducted.

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 &lt; 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 &lt; 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.

Phase 1 trial of ontuxizumab (MORAb-004) in children with relapsed or refractory solid tumors: A report from the Children's Oncology Group Phase 1 Pilot Consortium (ADVL1213)

BACKGROUND

Ontuxizumab is a humanized IgG monoclonal antibody that targets the cell-surface glycoprotein endosialin (tumor endothelial marker-1[TEM-1]/CD248) found on activated mesenchymal cells and certain tumors. Ontuxizumab binding to endosialin may interfere with platelet-derived growth factor signaling, prevent tumor stroma organization, and prevent new vessel formation.

METHODS

Ontuxizumab was administered intravenously on days 1, 8, 15, and 22 of a 28-day cycle at three dose levels (4, 8, and 12 mg/kg). Further dose escalation to 16 mg/kg was planned if the maximum tolerated dose (MTD) was not reached and the ontuxizumab systemic clearance was ≥30% higher in children compared to adults. Following determination of the MTD/recommended phase 2 dose, an additional cohort of six patients (<12 years) was enrolled for further pharmacokinetics (PK) evaluation.

RESULTS

Twenty-seven eligible patients (17 male, median age 15 years, range 3-21 years) were enrolled. Twenty-two patients (neuroblastoma [5], Ewing sarcoma [4], rhabdomyosarcoma [4], and other tumors [9]) were fully evaluable for toxicity. Five patients did not complete cycle 1 due to tumor progression. Two of 10 patients experienced dose-limiting toxicity of bacteremia (n = 1) and hyponatremia (n = 1) at 12 mg/kg. Grade ≤2 fever or infusion-related reactions occurred in 10 patients. Clearance was dose dependent and within 30% of adult value at 12 mg/kg.

CONCLUSION

Ontuxizumab administered weekly at 12 mg/kg appears to be well tolerated in children with relapsed or refractory solid tumors. The PK of ontuxizumab does not appear to be significantly different in children compared to adults.

Historical time to disease progression and progression-free survival in patients with recurrent/refractory neuroblastoma treated in the modern era on Children's Oncology Group early-phase trials

BACKGROUND

Early-phase trials in patients with recurrent neuroblastoma historically used an objective "response" of measureable disease (Response Evaluation Criteria In Solid Tumors [RECIST], without bone/bone marrow assessment) to select agents for further study. Historical cohorts may be small and potentially biased; to the authors' knowledge, disease recurrence studies from international registries are outdated. Using a large recent cohort of patients with recurrent/refractory neuroblastoma from Children's Oncology Group (COG) modern-era early-phase trials, the authors determined outcome and quantified parameters for designing future studies.

METHODS

The first early-phase COG trial enrollment (sequential) of 383 distinct patients with recurrent/refractory neuroblastoma on 23 phase 1, 3 phase 1/2, and 9 phase 2 trials (August 2002 to January 2014) was analyzed for progression-free survival (PFS), overall survival (OS), and time to disease progression (TTP). Planned frontline therapy for patients with high-risk neuroblastoma included hematopoietic stem cell transplantation (approximately two-thirds of patients underwent ≥1 hematopoietic stem cell transplantation); 13.2% of patients received dinutuximab.

RESULTS

From the time of the patient's first early-phase trial enrollment (383 patients), the 1-year and 4-year PFS rates ( ± standard error) were 21% ± 2% and 6% ± 1%, respectively, whereas the 1-year and 4-year OS rates were 57% ± 3% and 20% ± 2%, respectively. The median TTP was 58 days (interquartile range, 31-183 days [350 patients]); the median follow-up was 25.3 months (33 patients were found to be without disease recurrence/progression). The median time from diagnosis to first disease recurrence/progression was 18.7 months (range, 1.4-64.8 months) (176 patients). MYCN amplification and 11q loss of heterozygosity were prognostic of worse PFS and OS (P = .003 and P<.0001, respectively, and P = .02 and P = .03, respectively) after early-phase trial enrollment.

CONCLUSIONS

This recent COG cohort of patients with recurrent/refractory neuroblastoma is inclusive and representative. To the authors' knowledge, the current study is the first meta-analysis of PFS, TTP, and OS within the context of modern therapy. These results will inform the design of future phase 2 studies by providing a) historical context during the search for more effective agents; and, b) factors prognostic of PFS and OS after disease recurrence to stratify randomization. Cancer 2017;123:4914-23. © 2017 American Cancer Society.

Histology, fusion status, and outcome in metastatic rhabdomyosarcoma: A report from the Children's Oncology Group

BACKGROUND

Distinguishing alveolar rhabdomyosarcoma (ARMS) from embryonal rhabdomyosarcoma (ERMS) has historically been of prognostic and therapeutic importance. However, classification has been complicated by shifting histologic criteria required for an ARMS diagnosis. Children's Oncology Group (COG) studies after IRS-IV, which included the height of this diagnostic shift, showed both an increased number of ARMS and an increase in the proportion of fusion-negative ARMS. Following diagnostic standardization and histologic re-review of ARMS cases enrolled during this era, analysis of low-risk (D9602) and intermediate-risk (D9803) rhabdomyosarcoma (RMS) studies showed that fusion status rather than histology best predicts prognosis for patients with RMS. This analysis remains to be completed for patients with high-risk RMS.

PROCEDURE

We re-reviewed cases on high-risk COG studies D9802 and ARST0431 with an enrollment diagnosis of ARMS. We compared the event-free survival (EFS) and overall survival by histology, PAX-FOXO1 fusion, and clinical risk factors (Oberlin score) for patients with metastatic RMS using the log-rank test.

RESULTS

Histology re-review resulted in reclassification as ERMS for 12% of D9802 cases and 5% of ARST0431 cases. Fusion-negative RMS had a superior EFS to fusion-positive RMS; however, poorer outcome for metastatic RMS was most related to clinical risk factors including age, primary site, and number of metastatic sites.

CONCLUSIONS

In contrast to low- or intermediate-risk RMS, in metastatic RMS, clinical risk factors have the most impact on patient outcome. PAX-FOXO1 fusion is more common in patients with a high Oberlin score, but fusion status is not an independent biomarker of prognosis.

A phase 1 study of the c-Met inhibitor, tivantinib (ARQ197) in children with relapsed or refractory solid tumors: A Children's Oncology Group study phase 1 and pilot consortium trial (ADVL1111)

BACKGROUND

The c-Met receptor tyrosine kinase is dysregulated in many pediatric cancers. Tivantinib is an oral small molecule that inhibits the c-Met receptor tyrosine kinase. A phase 1 and pharmacokinetic (PK) trial evaluating tivantinib was conducted in children with relapsed/refractory solid tumors.

METHODS

Oral tivantinib capsules were administered twice daily with food, continuously in 28-day cycles. Dose levels 170, 200, and 240 mg/m² /dose were evaluated using a rolling-six design (Part A). In Part B, subjects received tivantinib powder sprinkled on food at the recommended phase 2 dose (RP2D) from Part A. PK, CYP2C19 genotyping, and baseline tumor tissue c-Met expression were analyzed.

RESULTS

Thirty-six patients were enrolled: 20 in Part A, 6 in a PK expansion cohort, and 10 in Part B. Fifteen patients had primary central nervous system tumors and 21 had solid tumors. In Part A, there were no dose-limiting toxicities. One grade 4 intracranial hemorrhage occurred in a patient with a progressive brain tumor in the expanded PK cohort (240 mg/m² ). PK analysis showed marked interpatient variability (20-fold) in the C_max and AUC_0-8h across all dose levels. Sprinkling tivantinib powder over food did not alter exposure. Membranous and total c-Met expression was moderate (2), low (4), or not detected (26). Two patients had stable disease as the best response.

CONCLUSIONS

The RP2D of tivantinib given with food in children with refractory solid tumors is 240 mg/m² /dose. PK of tivantinib in children demonstrated high variability. Objective responses were not observed in this phase 1 trial.

Targeting ALK With Crizotinib in Pediatric Anaplastic Large Cell Lymphoma and Inflammatory Myofibroblastic Tumor: A Children's Oncology Group Study

Purpose Fusions involving the ALK gene are the predominant genetic lesion underlying pediatric anaplastic large cell lymphomas (ALCL) and inflammatory myofibroblastic tumors (IMTs). We assessed the activity of the ALK inhibitor crizotinib in patients who had no known curative treatment options at diagnosis or with relapsed/recurrent disease. Methods In this study, 26 patients with relapsed/refractory ALK-positive ALCL and 14 patients with metastatic or inoperable ALK-positive IMT received crizotinib orally twice daily. Study objectives were measurement of efficacy and safety. Correlative studies evaluated the serial detection of NPM-ALK fusion transcripts in patients with ALCL. Results The overall response rates for patients with ALCL treated at doses of 165 (ALCL165) and 280 (ALCL280) mg/m² were 83% and 90%, respectively. The overall response rate for patients with IMT (treated at 100, 165, and 280 mg/m²/dose) was 86%. A complete response was observed in 83% (five of six) of ALCL165, 80% (16 of 20) of ALCL280, and 36% (five of 14) of patients with IMT. Partial response rates were 0% (none of six), 10% (two of 20), and 50% (seven of 14), respectively. The median duration of therapy was 2.79, 0.4, and 1.63 years, respectively, with 12 patients ceasing protocol therapy to proceed to transplantation. The most common drug-related adverse event was decrease in neutrophil count in 33% and 70% of the ALCL165 and ALCL280 groups, respectively, and in 43% of patients with IMT. Levels of NPM-ALK decreased during therapy in most patients with ALCL. Conclusion The robust and sustained clinical responses to crizotinib therapy in patients with relapsed ALCL and metastatic or unresectable IMT highlight the importance of the ALK pathway in these diseases.

A phase 1 trial of temsirolimus and intensive re-induction chemotherapy for 2nd or greater relapse of acute lymphoblastic leukaemia: a Children's Oncology Group study (ADVL1114)

The phosphatidylinositol 3-kinase (PI3K)/mammalian (or mechanistic) target of rapamycin (mTOR) signalling pathway is commonly dysregulated in acute lymphoblastic leukaemia (ALL). A phase 1 trial of the mTOR inhibitor temsirolimus in combination with UKALL R3 re-induction chemotherapy was conducted in children and adolescents with second or greater relapse of ALL. The initial temsirolimus dose level (DL1) was 10 mg/m² weekly × 3 doses. Subsequent patient cohorts received temsirolimus 7·5 mg/m² weekly × 3 doses (DL0) or, secondary to toxicity, 7·5 mg/m² weekly × 2 doses (DL-1). Sixteen patients were enrolled, 15 were evaluable for toxicity. Dose-limiting toxicity (DLT) occurred at all three dose levels and included hypertriglyceridaemia, mucositis, ulceration, hypertension with reversible posterior leucoencephalopathy, elevated gamma-glutamyltransferase or alkaline phosphatase and sepsis. The addition of temsirolimus to UKALL R3 re-induction therapy resulted in excessive toxicity and was not tolerable in children with relapsed ALL. However, this regimen induced remission in seven of fifteen patients. Three patients had minimal residual disease levels <0·01%. Inhibition of PI3K signalling was detected in patients treated at all dose levels of temsirolimus, but inhibition at an early time point did not appear to correlate with clinical responses at the end of re-induction therapy.

First-dose and steady-state pharmacokinetics of orally administered crizotinib in children with solid tumors: a report on ADVL0912 from the Children's Oncology Group Phase 1/Pilot Consortium

Purpose

Characterize the pharmacokinetics of oral crizotinib in children with cancer.

Methods

Sixty-four children with solid tumors or anaplastic large-cell lymphoma (ALCL) enrolled on a phase 1/2 trial of the ALK, MET and ROS1 inhibitor, crizotinib, had pharmacokinetic sampling after the first dose (n = 15) or at steady state (n = 49). Dose levels studied were 100, 130, 165, 215, 280 and 365 mg/m²/dose administered twice daily. Two capsule and two oral liquid formulations were used over the course of the trial. Crizotinib was quantified with a validated HPLC/tandem mass spectrometry method with a lower limit of detection of 0.2 ng/mL. Pharmacokinetic parameters were derived using non-compartmental analysis.

Results

Time to peak plasma concentration was 4 h. At 280 mg/m² (MTD), mean (±SD) steady-state peak plasma concentration was 717 ± 201 ng/mL, and steady-state trough plasma concentration was 480 ± 176 ng/mL. At steady state, AUC_0–τ was proportional to dose over the dose range of 215–365 mg/m²/dose. Apparent clearance of crizotinib was 731 ± 241 mL/min/m². Steady-state AUC_0–τ at 280 mg/m²/dose was 2.5-fold higher than the AUC_0–∞ in adults receiving 250 mg (~140 mg/m²). Age, sex and drug formulation do not account for the inter-subject variability in AUC_0–τ at steady state. The accumulation index was 4.9, and the half-life estimated from the accumulation index was 36 h.

Conclusions

The pharmacokinetics of oral crizotinib in children is similar to that in adults. Steady-state trough-free crizotinib concentrations in plasma at the MTD exceed inhibitory concentrations of crizotinib in ALCL cell lines.

ClinicalTrials.gov identifier

NCT00939770.

Intensive Multiagent Therapy, Including Dose-Compressed Cycles of Ifosfamide/Etoposide and Vincristine/Doxorubicin/Cyclophosphamide, Irinotecan, and Radiation, in Patients With High-Risk Rhabdomyosarcoma: A Report From the Children's Oncology Group

PURPOSE

Patients with metastatic rhabdomyosarcoma (RMS), except those younger than 10 years with embryonal RMS, have an estimated long-term event-free survival (EFS) of less than 20%. The main goal of this study was to improve outcome of patients with metastatic RMS by dose intensification with interval compression, use of the most active agents determined in phase II window studies, and use of irinotecan as a radiation sensitizer.

PATIENTS AND METHODS

Patients with metastatic RMS received 54 weeks of therapy: blocks of therapy with vincristine/irinotecan (weeks 1 to 6, 20 to 25, and 47 to 52), interval compression with vincristine/doxorubicin/cyclophosphamide alternating with etoposide/ifosfamide (weeks 7 to 19 and 26 to 34), and vincristine/dactinomycin/cyclophosphamide (weeks 38 to 46). Radiation therapy occurred at weeks 20 to 25 (primary) but was also permitted at weeks 1 to 6 (for intracranial or paraspinal extension) and weeks 47 to 52 (for extensive metastatic sites).

RESULTS

One hundred nine eligible patients were enrolled, with a median follow-up of surviving patients of 3.8 years (3-year EFS for all patients, 38% [95% CI, 29% to 48%]; survival, 56% [95% CI, 46% to 66%]). Patients with one or no Oberlin risk factor (age > 10 years or < 1 year, unfavorable primary site of disease, ≥ three metastatic sites, and bone or bone marrow involvement) had a 3-year EFS of 69% (95% CI, 52% to 82%); high-risk patients with two or more risk factors had a 3-year EFS of 20% (95% CI, 11% to 30%). Toxicity was similar to that on prior RMS studies.

CONCLUSION

Patients with metastatic RMS with one or no Oberlin risk factor had an improved 3-year EFS of 69% on ARST0431 compared with an historical cohort from pooled European and US studies; those with two or more risk factors have a dismal prognosis, and new approaches are needed for this very-high-risk group.

A phase 1 dosing study of ruxolitinib in children with relapsed or refractory solid tumors, leukemias, or myeloproliferative neoplasms: A Children's Oncology Group phase 1 consortium study (ADVL1011)

BACKGROUND

Ruxolitinib, an orally bioavailable JAK1/JAK2 inhibitor, may treat cancers with CRLF2 and/or JAK pathway mutations.

PROCEDURE

A phase 1 trial of ruxolitinib was performed to determine the maximum tolerated or recommended phase 2 dose, dose-limiting toxicities (DLTs), pharmacokinetics (PK), and pharmacodynamics (PD) in children with recurrent/refractory solid tumors (STs). Ruxolitinib was administered twice daily (BID) in 28-day cycles at five dose levels (15, 21, 29, 39, and 50 mg/m(2)/dose). PK and PD studies were performed during cycle 1. Toxicity, preliminary efficacy, and PK/PD were also assessed in children with relapsed/refractory hematologic malignancies (HMs).

RESULTS

Forty-nine patients were enrolled, 28 with STs (dose escalation cohort) and 21 with HMs. Ruxolitinib was well-tolerated with one DLT per cohort of six patients at dose levels (DLs) 2-5. One patient with an ST had grade 5 multi-organ failure at DL2. One patient each at DL3 and DL4 had a grade 4 neutropenia, and one patient at DL5 had a grade 4 creatinine phosphokinase elevation. No objective responses were observed in patients with STs. One patient with polycythemia vera achieved a partial response and received 18 cycles of ruxolitinib. The PK of ruxolitinib were similar to that in adults. Partial inhibition of phosphorylated JAK2, STAT5, and S6 was observed in in vitro plasma inhibitory activity PD assay.

CONCLUSION

Ruxolitinib was well tolerated in children with refractory cancer. The recommended phase 2 dose for continuous BID oral administration is 50 mg/m(2)/dose. Subsequent evaluation of ruxolitinib in combination with cytotoxic chemotherapy in children, adolescents, and young adults with JAK-mutant leukemias is planned.

Phase I trial of Seneca Valley Virus (NTX-010) in children with relapsed/refractory solid tumors: a report of the Children's Oncology Group

BACKGROUND

To determine the MTD of Seneca Valley Virus (NTX-010) in children with relapsed/refractory solid tumors. Patients (≥ 3-≤ 21 years) with neuroblastoma, rhabdomyosarcoma, or rare tumors with neuroendocrine features were eligible.

PROCEDURE

Part A (single dose of NTX-010) enrolled 13 patients at three dose levels (1 × 10(9) viral particles (vp)/kg [n = 6], 1 × 10(10) vp/kg [n = 3], 1 × 10(11) vp/kg [n = 4]). Diagnoses included neuroblastoma (n = 9), rhabdomyosarcoma (n = 2), carcinoid tumor (n = 1), and adrenocorticocarcinoma (n = 1). Part B added cyclophosphamide (CTX) (oral CTX (25 mg/m(2) /day) days 1-14 and IV CTX (750 mg/m(2) ) days 8 and 29) to two doses of NTX-010 (1 × 10(11) vp/kg, days 8 and 29). Nine patients enrolled to Part B. Diagnoses included neuroblastoma (n = 3), rhabdomyosarcoma (n = 1), Wilms tumor (n = 3), and adrenocorticocarcinoma (n = 2).

RESULTS

Twelve patients on Part A were evaluable for toxicity. There was a single DLT (grade 3 pain) at dose level 1. Additional grade ≥ 3 related adverse events (AEs) included leukopenia (n = 1), neutropenia (n = 3), lymphopenia (n = 3), and tumor pain (n = 1). No DLTs occurred on part B. Other grade ≥ 3 related AEs on Part B included: Leukopenia (n = 3), nausea (n = 1), emesis (n = 1), anemia (n = 1), neutropenia (n = 4), platelets (n = 1), alanine aminotransferase (n = 1), and lymphopenia (n = 2). All patients cleared NTX-010 from blood and stool by 3 weeks with 17/18 patients developing neutralizing antibodies.

CONCLUSION

NTX-010 is feasible and tolerable at the dose levels tested in pediatric patients with relapsed/refractory solid tumors either alone or in combination with cyclophosphamide. However, despite the addition of cyclophosphamide, neutralizing antibodies appeared to limit applicability.

A phase I trial and viral clearance study of reovirus (Reolysin) in children with relapsed or refractory extra-cranial solid tumors: a Children's Oncology Group Phase I Consortium report

BACKGROUND

Reovirus is a naturally occurring human virus that is cytopathic to malignant cells possessing an activated Ras signaling pathway. We conducted a phase I trial of Reolysin, a manufactured, proprietary isolate of purified reovirus, in children with relapsed/refractory extracranial solid tumors to define the recommended phase 2 dose (RP2D), toxicities, and pharmacokinetic properties when administered as a single agent or in combination with cyclophosphamide.

PROCEDURES

Reolysin was administered intravenously for 5 consecutive days, every 28 days. Using a 3 + 3 design, the following dose levels were evaluated: 3 × 10(8) Tissue Culture Inhibitory Dose 50% (TCID50 )/kg; 5 × 10(8) TCID50 /kg (maximum dose was 3 × 10(10) TCID50 ); and 5 × 10(8) TCID50 /kg plus oral cyclophosphamide (50 mg/m(2) /day × 21 days).

RESULTS

Twenty-nine patients were enrolled; 28 were eligible and 24 were evaluable for toxicity and response. There were no hematologic dose-limiting toxicities. Grade 5 respiratory failure and a Grade 5 thromboembolic event were reported, both in the setting of progressive disease. The median time to clear the reovirus viremia was 6.5 days. Eight of 24 patients were viremic beyond the 5 days of therapy, all were negative by day 17. No patient had detectable viral RNA in saliva or stool. There were no objective responses.

CONCLUSIONS

Reolysin at a dose of 5 × 10(8) TCID50 /kg daily for 5 days was well tolerated in children alone and in combination with oral cyclophosphamide. Virus was cleared rapidly from the serum and shedding in stool and saliva was not detectable.

Abstract B74: A phase I trial and viral clearance study of reovirus (Reolysin) in children with relapsed or refractory extra-cranial solid tumors: A Children's Oncology Group phase I consortium report

Purpose: Reovirus (Respiratory Enteric Orphan virus) Serotype 3 – Dearing Strain is a naturally occurring, ubiquitous, non-enveloped human virus. Reovirus has been shown to replicate specifically in, and be cytopathic to, transformed cells possessing an activated Ras signaling pathway. We conducted a Phase I trial of Reolysin, a manufactured, purified reovirus, in children with relapsed or refractory extracranial solid tumors to define a maximum tolerated or recommended phase 2 dose (PP2D), as well as its toxicities and pharmacokinetic properties.

Experimental Design: Reovirus was administered intravenously, daily for 5 consecutive days every 28 days for up to 12 cycles. Using a 3+3 design, two planned dose levels were evaluated: 3 x 108 TCID50/kg (∼60% of the adult dose) and 5 x 108 TCID50/kg. The cohort was expanded at the RP2D to obtain additional single agent safety and viral clearance data. Additionally, a 3rd cohort received the RP2D ( 5 x 108 TCID50/kg Reolysin) plus oral cyclophosphamide (50 mg/m2/day x 21 days). Twice weekly quantitative real time PCR of reovirus genomic RNA from serum, stool and saliva, and antiviral immune response by ELISA was evaluated after the first two courses.

Results: Twenty-nine patients were enrolled, one was subsequently found to be ineligible. Of the 28 eligible patients, 5 are not evaluable (one is still on study) for dose-limiting toxicity (DLT). Six evaluable patients were enrolled on dose level 1; one with extensive pulmonary metastases experienced grade 5 respiratory failure attributed to their underlying disease. Given the severity of the event, the cohort was expanded to six without further DLTs. None of the six evaluable patients enrolled on dose levels 2 and 3, respectively, had a DLT. One patient in the single agent expansion cohort experienced a grade 5 thromboembolic event, grade 4 hypokalemia, grade 3 hypocalcemia, grade 4 hypophosphatemia, grade 3 hyponatremia, and grade 3 hypoalbuminemia possibly attributed to the Reolysin. With twice weekly monitoring by quantitative real time PCR, the median time to a clear the reovirus viremia was 6.5 days. Seven patients were viremic beyond the five days of therapy. No patient had detectable virus in their serum beyond day 17. Only one patient had detectable viral RNA in saliva or stool (day 6 in saliva). Four patients receiving the RP2D had stable disease at the end of one cycle, all others had progressive disease. All patients developed an anti-reovirus antibody during the first cycle of treatment. In three patients receiving a second cycle of reovirus, peak viral levels were reduced relative to cycle 1. There were no objective responses.

Conclusions: Reovirus at a dose of 5 x 108 TCID50/kg daily for 5 days is well tolerated alone and in combination with oral cyclophosphamide. Virus is cleared rapidly from the serum of most patients, even when given with cyclophosphamide, and shedding in stool and saliva is not seen.

Citation Format: Edward A. Kolb, Valerie B. Sampson, Deborah Stabley, Alexa Walter, Timothy P. Cripe, Pooja Hingorani, Charlotte Hsieh Ahern, Ashish M. Ingle, Brenda J. Weigel, Susan B. Blaney. A phase I trial and viral clearance study of reovirus (Reolysin) in children with relapsed or refractory extra-cranial solid tumors: A Children's Oncology Group phase I consortium report. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr B74.

A therapeutic trial of decitabine and vorinostat in combination with chemotherapy for relapsed/refractory acute lymphoblastic leukemia

DNA hypermethylation and histone deacetylation are pathways of leukemia resistance. We investigated the tolerability and efficacy of decitabine and vorinostat plus chemotherapy in relapse/refractory acute lymphoblastic leukemia (ALL). Decitabine (15 mg/m(2) iv) and vorinostat (230 mg/m(2) PO div BID) were given days 1-4 followed by vincristine, prednisone, PEG-asparaginase, and doxorubicin. Genome wide methylation profiles were performed in 8 matched patient bone marrow (BM) samples taken at day 0 and day 5 (postdecitabine). The median age was 16 (range, 3-54) years. All patients had a prior BM relapse, with five relapsing after allogeneic transplant. The most common nonhematological toxicities possibly related to decitabine or vorinostat were infection with neutropenia (grade 3; n = 4) and fever/neutropenia (grade 3, n = 4; grade 4, n = 1). Of the 13 eligible patients, four achieved complete remission without platelet recovery (CRp), two partial response (PR), one stable disease (SD), one progressive disease (PD), two deaths on study and three patients who did not have end of therapy disease evaluations for an overall response rate of 46.2% (CRp + PR). Following decitabine, significant genome-wide hypo-methylation was observed. Comparison of clinical responders with nonresponders identified methylation profiles of clinical and biological relevance. Decitabine and vorinostat followed by re-Induction chemotherapy was tolerable and demonstrated clinical benefit in relapsed patients with ALL. Methylation differences were identified between responders and nonresponders indicating interpatient variation, which could impact clinical outcome. This study was registered at www.clinicaltrials.gov as NCT00882206.

A phase I trial of imetelstat in children with refractory or recurrent solid tumors: a Children's Oncology Group Phase I Consortium Study (ADVL1112)

PURPOSE

Imetelstat is a covalently-lipidated 13-mer thiophosphoramidate oligonucleotide that acts as a potent specific inhibitor of telomerase. It binds with high affinity to the template region of the RNA component of human telomerase (hTERC) and is a competitive inhibitor of telomerase enzymatic activity. The purpose of this study was to determine the recommended phase II dose of imetelstat in children with recurrent or refractory solid tumors.

EXPERIMENTAL DESIGN

Imetelstat was administered intravenously more than two hours on days 1 and 8, every 21 days. Dose levels of 225, 285, and 360 mg/m(2) were evaluated, using the rolling-six design. Imetelstat pharmacokinetic and correlative biology studies were also performed during the first cycle.

RESULTS

Twenty subjects were enrolled (median age, 14 years; range, 3-21). Seventeen were evaluable for toxicity. The most common toxicities were neutropenia, thrombocytopenia, and lymphopenia, with dose-limiting myelosuppression in 2 of 6 patients at 360 mg/m(2). Pharmacokinetics is dose dependent with a lower clearance at the highest dose level. Telomerase inhibition was observed in peripheral blood mononuclear cells at 285 and 360 mg/m(2). Two confirmed partial responses, osteosarcoma (n = 1) and Ewing sarcoma (n = 1), were observed.

CONCLUSIONS

The recommended phase II dose of imetelstat given on days 1 and 8 of a 21-day cycle is 285 mg/m(2).