Adolescent and young adult Hodgkin lymphoma patients at risk for subcutaneous fat gain during early cancer treatment: a brief report

Computed tomography scans were assessed for subcutaneous fat area and density at thoracic vertebra 4 in 65 adolescent and young adult (AYA) patients with Hodgkin lymphoma. Subcutaneous fat was quantified over 3 timepoints; (1) baseline, (2) end of initial anthracycline treatment (EOT) and (3) 1 year. Fat area increased at EOT (62.3 ± 5.4 cm/m2 vs 53.5 ± 5.0 cm/m2, p < 0.01) and 1 year (65.8 ± 5.6 cm/m2 vs 53.5 ± 5.0 cm/m2, p < 0.01) compared to baseline. Fat density significantly decreased at EOT (-91.2 ± 1.4 HU vs -86.5 ± 1.4 HU, p < 0.01) and at 1 year (-90.3 ± 1.6 HU vs -86.5 ± 1.4 HU, p = 0.01) compared to baseline. Female, radiation receiving, and anthracycline dosage >250mg/m2subgroups experienced significant fat gain (p < 0.05 for all). Female AYA Hodgkin lymphoma patients receiving radiation, and/or high-dose anthracyclines may be at higher risk of subcutaneous fat gain during therapy.

Poor Sit-to-Stand Performance in Adolescent and Young Adult Patients with Sarcoma

Background: Adolescents and young adult (AYA) patients with sarcoma are at heightened risk of reduced physical capacity and disease-related weakness. Sit-to-stand (STS) performance correlates with lower extremity functionality and activities of daily living; however, little is known regarding the relationship between muscular status and STS performance in patients with sarcoma. This study assessed STS performance in patients with sarcoma and the association between STS performance and the skeletal muscle index (SMI) and skeletal muscle density (SMD). Methods: This study included 30 patients with sarcoma (15-39 years old) treated with high-dose doxorubicin. Patients performed the five-times-STS test before starting treatment and 1 year after the baseline test. STS performance was correlated with SMI and SMD. SMI and SMD were quantified using computed tomography scans taken at the level of the 4th thoracic vertebra (T4). Results: Mean performance on the STS test at baseline and 1 year was 2.2-fold and 1.8-fold slower than the age-matched general population, respectively. A lower SMI was associated with worse performance on the STS test (p = 0.01). Similarly, lower SMD at baseline was also associated with poorer STS performance (p < 0.01). Conclusion: Patients with sarcoma have very poor STS performance at baseline and 1 year, which was accompanied by low SMI and SMD at T4.The inability for AYAs to return to healthy age normative STS standards by 1 year may indicate a need for early interventions to enhance skeletal muscle recovery and promote physical activity during and after treatment.

Prognostic Value of Cell-Surface Vimentin-Positive CTCs in Pediatric Sarcomas

BACKGROUND

Despite advances in care, the 5 year overall survival for patients with relapsed and or metastatic sarcoma remains as low as < 35%. Currently, there are no biomarkers available to assess disease status in patients with sarcomas and as such, disease surveillance remains reliant on serial imaging which increases the risk of secondary malignancies and heightens patient anxiety.

METHODS

Here, for the first time reported in the literature, we have enumerated the cell surface vimentin (CSV+) CTCs in the blood of 92 sarcoma pediatric and adolescent and young adult (AYA) patients as a possible marker of disease.

RESULTS

We constructed a ROC with an AUC of 0.831 resulting in a sensitivity of 85.3% and a specificity of 75%. Additionally, patients who were deemed to be CSV+ CTC positive were found to have a worse overall survival compared to those who were CSV+ CTC negative. We additionally found the use of available molecular testing increased the accuracy of our diagnostic and prognostic tests.

CONCLUSIONS

Our findings indicate that CSV+ CTCs have prognostic value and can possibly serve as a measure of disease burden.

Abstract P365: Neutrophils Contribute To Doxorubicin-induced Cardiotoxicity

Doxorubicin is one for the most effective chemotherapy agents for the treatment of childhoodcancer. Unfortunately Dox treatment causes damage to the heart and childhood cancer survivorsare at higher risk of developing cardiovascular disease at an earlier age than community controls.Understanding the mechanisms by which Dox induces cardiotoxicity is crucial to identifyingpreventive interventions. Innate immune cells, in particular neutrophils, have been shown to playa role in other forms of cardiac disease such as atherosclerosis and myocardial infarction.However, the role of these immune cells in Dox-induced cardiotoxicity is poorly understood.We hypothesized that neutrophils contribute to the cardiac damage caused by Dox treatment andinvestigated this hypothesis using our juvenile mouse cardiotoxicity model. Mice were treated withDoxorubicin for 2 weeks. Echocardiograms were performed before and 24 hours after therapy.Hearts were then harvested, and the heart tissue evaluated for neutrophil infiltration using flowcytometry. There was a decrease in heart function as quantified by echocardiography (ejection fraction [EF] and fractional shortening [FS]) 24 hours after therapy which persisted for 12 weeks. There was also an elevation in neutrophils in heart tissue of Dox-treated mice as compared to controls. To determine whether neutrophils contributed to the functional decline seen in the Dox-treated mice, neutrophils were depleted using an anti-Ly6G antibody prior to Dox treatment. Neutrophil depletion was confirmed by flow cytometry in the blood and hearts of Dox-treated mice. Neutrophil depletion prevented the Dox-induced decrease in EF and FS seen at 24 hours and 12weeks after therapy. Additionally, we also analyzed heart sections for fibrosis and found that neutrophil depletion protected against excessive collagen deposition 12 weeks after therapy. Together these findings suggest that neutrophils contribute Dox-induced cardiotoxicity and that targeting neutrophils may be a potential strategy to prevent Dox-induced cardiotoxicity.

Cell-surface vimentin positive circulating tumor cells as a diagnostic and prognostic indicator in pediatric sarcoma patients

e15022

Background: Despite advances in care, the 5 year overall survival for patients with relapsed and or metastatic sarcoma remains as low as < 35%. Currently, there are no biomarkers available to assess disease status in patients with sarcomas and as such, disease surveillance remains only reliant on serial imaging which increases the risk of secondary malignancies and heightens patient anxiety. Methods: Here, we enumerated the cell surface vimentin (CSV+) CTCs in the blood of 92 sarcoma pediatric and adolescent and young adult (AYA) patients. Results: We discovered the CSV+CTC could serve as a possible biomarker of disease with sensitivity of 85.3% and specificity of 75%. Significantly, patients who were deemed to be CSV+ CTC positive were found to have a worse overall survival compared to those who were CSV+ CTC negative (773 days vs 2622 days). Addition of readily available genetic analyses improved the sensitivity in both diagnostic and prognostic tests. Conclusions: Our findings indicate that CSV+ CTCs have both diagnostic and prognostic value and can possibly serve as a measure of disease burden.

A phase I trial of aerosol gemcitabine for the treatment of patients with solid tumors and lung metastases

TPS3645

Background: Pre-clinical studies of aerosol gemcitabine (GCB) in mice and dogs with osteosarcoma (OS) lung metastases demonstrated therapeutic efficacy. Aerosol GCB administered once weekly proved to be safe in adults with lung cancer. Direct delivery of GCB to the lungs via inhalation may offer higher drug concentration in the tumor with fewer side effects. We initiated a Phase I study to evaluate the feasibility and safety of aerosol GCB treatment in patients >12 years with solid tumors and lung metastases (2015-0720- NCT03093909). Methods: Eligibility criteria: 1) Diagnosis of solid tumor with lung metastases, 2) willing to comply with protocol therapy, 3) adequate organ function, 4) patient age > 12 and < 50 years, 5) good performance status, 6) resolution of all acute toxic effects of any prior anti-cancer therapy, and 7) no radiotherapy within 2 weeks. Patients who previously received systemic GCB are eligible. Objectives: To determine the maximum tolerated dose (MTD) and toxicities of aerosol GCB, to evaluate for drug spillover into the circulation, and to preliminarily assess the anti-tumor activity. Correlative studies include effect of aerosol GCB on immune cell infiltration in the lung, autophagy, apoptosis, heat shock protein 27, evidence of DNA strand breaks (gH2AX) and expression of human equilibrative nucleoside transporter-1.Aerosol GCB is administered via a breath-induced nebulizer twice a week in 28-day cycles. A maximum of 6 dose levels will be studied; the starting dose is 0.75 mg/kg twice weekly. If no progressive disease or unacceptable treatment-related toxicity, patients may continue for 12 cycles. The study uses the accelerated titration method for the first 2 dose levels then the 3+3 design for the remaining dose levels. After determining the MTD, we will evaluate the defined MTD in an expansion cohort of 14 patients with relapsed OS. Symptoms, pulse oximetry, and pulmonary function are assessed prior to each nebulized dose using remote spirometry that allows raw numbers and flow-volume curves to be uploaded and transmitted via bluetooth to an android tablet provided to patients. Data is transmitted to a web portal and captured in a HIPAA-compliant web-based database (REDCap) that is accessible to the research team. Results: To date, the study enrolled 4 patients and accrual is ongoing at dose level 3. Conclusions: This study will provide information on the feasibility and safety of aerosol GCB. If proven to be feasible and safe, it can potentially offer a novel approach to treat metastatic OS to the lungs while minimizing systemic toxicity. Clinical trial information: NCT03093909 .

Abstract 1345: Automated capture and analysis of circulating tumor cells across different types of tumors in pediatric cancer patients

The clinical utility of blood analysis such as circulating tumor cells (CTCs) has garnered increasing interest in recent years. However very few studies were conducted in pediatric cancer patients especially in brain tumor, osteosarcoma, and leukemia patients due to the lack of an effective tool to isolate/capture CTC from these patients. For example, only three independent studies were published to investigate CTC capture from adult brain tumor patients but zero studies were conducted with pediatric brain cancer patients. Our previous studies showed the high specificity of using cell surface vimentin (CSV) to identify and capture CTCs from various types of adult tumor patients using a manual isolation method. Here we present the first automated system for capturing CTCs across different types of pediatric tumors. This automated system utilizes the Abnova CytoQuest system loaded with the CSV antibody 84-1-coated microfluidic cassette for capturing CTCs from peripheral blood samples. This automated assay was very sensitive because as few as one tumor cell can be captured out from one million normal cells. Based on our preliminary study, our success rate for non-DIPG brain tumor, ALL, and AML patients is 100%. This success provides a potential opportunity for analyzing brain tumor genetic properties using blood samples instead of the invasive tumor biopsy; likewise, this high sensitivity assay opens up clinical opportunities to use this assay for transplant and treatment decision making.

Note: This abstract was not presented at the meeting.

Citation Format: Izhar S. Batth, Wafik Zaky, Soumen Khatua, Najat C. Daw, Kris M. Mahadeo, Sajad Khazal, Aisha Albert, Wilber Huang, Diva Chen, Jonathan B. Gill, Eugenie Kleinerman, Richard Gorlick, Shulin Li. Automated capture and analysis of circulating tumor cells across different types of tumors in pediatric cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1345.

Alpha Particle Radium 223 Dichloride in High-risk Osteosarcoma: A Phase I Dose Escalation Trial

PURPOSE

The prognosis of metastatic osteosarcoma continues to be poor. We hypothesized that alpha-emitting, bone-targeting radium 223 dichloride (²²³RaCl₂) can be safely administered to patients with osteosarcoma and that early signals of response or resistance can be assessed by quantitative and qualitative correlative imaging studies and biomarkers.

PATIENTS AND METHODS

A 3+3 phase I, dose-escalation trial of ²²³RaCl₂ (50, 75, and 100 kBq/kg) was designed in patients with recurrent/metastatic osteosarcoma aged ≥15 years. Objective measurements included changes in standardized uptake values of positron emission tomography (PET; 18FDG and/or NaF-18) and single-photon emission CT/CT (99mTc-MDP) as well as alkaline phosphatase and bone turnover markers at baseline, midstudy, and the end of the study.

RESULTS

Among 18 patients enrolled (including 15 males) aged 15-71 years, tumor locations included spine (n = 12, 67%), pelvis (n = 10, 56%), ribs (n = 9, 50%), extremity (n = 7, 39%), and skull (n = 2, 11%). Patients received 1-6 cycles of ²²³RaCl₂; cumulative doses were 6.84-57.81 MBq. NaF PET revealed more sites of metastases than did FDG PET. One patient showed a metabolic response on FDG PET and NaF PET. Four patients had mixed responses, and one patient had a response in a brain metastasis. Bronchopulmonary hemorrhage from Grade 3 thrombocytopenia (N = 1) was a DLT. The median overall survival time was 25 weeks.

CONCLUSIONS

The first evaluation of the safety and efficacy of an alpha particle in high-risk osteosarcoma shows that the recommended phase II dose for ²²³RaCl₂ in osteosarcoma is 100 kBq/kg monthly (twice the dose approved for prostate cancer), with minimal hematologic toxicity, setting the stage for combination therapies.

Abstract 1843: Combination therapy targeting Rb/Wee1 kinase pathways for rhabdomyosarcoma treatment

Introduction

Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma. New therapeutic strategies are needed particularly for high-risk patients where the survival rate is 20-40%. The FDA approved CDK4/6 inhibitor palbociclib (PD), and the WEE1 kinase inhibitor MK-1775 have anticancer effects when used as single agents. PD causes cell arrest at G1 phase (requiring intact Rb), while MK-1775 promotes cell death by abrogating DNA damage during the G2/M checkpoint phase by forcing premature mitosis entry. As the two drugs target tumor cells at different phases of the cell cycle, cells that are not in the targeted phase may escape single therapy. We hypothesized that sequential combination therapy will increase therapeutic efficacy. The use of PD first, will induce the cells to go under G1 arrest. Upon recovery, more cells will synchronize in the S/G2 phase, increasing their susceptibility to MK1775, resulting in synergistic cell killing.

Methods

Rb+ RMS (Rh-30) and Rb- osteosarcoma (OS) cell lines (CCH-D, LM7, and SASO2) were treated with increasing doses of PD for 6 days, then stained with propidium iodide (PI) and analyzed for cell cycle status to determine whether PD induced G1 arrest. To determine the optimal recovery time for Rb+ cells to be synchronized in S/G2 phase, cells were treated with PD (IC50-IC75) for 6 days and then were harvested either immediately or after 3-24 h recovery in drug free medium. Cells were stained with PI for cell cycle analysis. A 12-day long combination therapy assay was performed with or without recovery time between the two treatments. Combination index (CI) was calculated by using the statistical program calcusyn to determine whether the combinatorial drug treatment had acted in an antagonistic, additive or synergistic manner.

Results

Six days of treatment with PD resulted in reversible G1 arrest only in Rb+ cell lines, confirming that Rb, the downstream target of CDK4, must be intact to induce G1 arrest by palbociclib. Six days of treatment with PD followed by 9-12 h recovery in fresh medium (the optimal recovery time prior to treatment with MK-1775), led to re-entry of the Rb+ Rh-30 cells into the cell cycle and successful synchronization at S/G2 phase. By contrast, Rb- cells failed to arrest in G1 phase following treatment with PD and were not synchronized at S/G2 phase. Since cells synchronized in S/G2 phase are more vulnerable to MK1775, combination therapy resulted in a synergistic effect in the Rb+ cells but an antagonistic effect in the Rb- cells.

Conclusion:

Our results suggest that the combination therapy strategy of PD preceding MK1775 may be a novel therapeutic approach for patients with Rb+ RMS. This strategy will be investigated in xenograft and PDX RMS model.

Citation Format: Simin Kiany, Gangxiong Huang, Melanie Justice, Khandan Keyomarsi, Eugenie Kleinerman. Combination therapy targeting Rb/Wee1 kinase pathways for rhabdomyosarcoma treatment [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 1843.

Hes4: A potential prognostic biomarker for newly diagnosed patients with high-grade osteosarcoma

BACKGROUND

Prognostic biomarkers for osteosarcoma (OS) at the time of diagnosis are lacking. Necrotic response of OS to preoperative chemotherapy correlates with survival and is determined 3-4 months after diagnosis. The purpose of this study is to identify biomarkers that will stratify patients into good or poor responders to chemotherapy at diagnosis and determine the role of potential biomarkers in OS pathogenesis.

PROCEDURE

Because OS may be caused by disruptions of osteogenic differentiation, and the Notch pathway is one regulator of bone development, we examined the link between Notch effectors, OS differentiation, and OS outcome. We probed the R2: Genomics Analysis and Visualization Platform for RNA expression levels of Notch targets in mixed high-grade OS pretreatment biopsies. We used human OS cell lines in vitro and in mice to determine the role of the Notch target hairy/enhancer of split 4 (Hes4) in OS.

RESULTS

We found that in OS patients, high expression of Hes4 is correlated with decreased metastasis-free and overall survival. Human OS cells that overexpress Hes4 are more immature and have an increased invasive capacity in vitro. This was not universal to all Notch effectors, as Hes1 overexpression induced opposing effects. When injected into NSG mice, Hes4-overexpressing OS cells produced significantly larger, more lytic tumors and significantly more metastases than did control cells.

CONCLUSIONS

Hes4 overexpression promotes a more aggressive tumor phenotype by preventing osteoblastic differentiation of OS cells. Hes4 expression may allow for the stratification of patients into good or poor responders to chemotherapy at diagnosis.

Abstract A65: Immune modulation of natural killer cell adoptive transfer for the treatment of Osteosarcoma lung metastastasis: Targeting the PD-1/ PDL-1 signaling pathway

Osteosarcoma (OS) is the most common primary malignant bone tumor in children. Pulmonary metastasis is the major cause of mortality in OS patients with a 25-30 % 5-year survival rate. Therefore, development of novel targeted approaches like immunotherapy has been the interest of investigators.

Previously, we have demonstrated that Liposomal muramyl tripeptipe phosphatidyl ethanolamine (L-MTP-PE) reduced the metastatic burden in animal models and caused an 8% improvement in the overall survival of patients with OS metastatic disease through macrophage activation. The adoptive transfer of mature natural killer (NK) cells activated ex vivo has exhibited anti-tumor efficacy in breast cancer and lymphoma models. It has been shown that NK cells exert cytotoxicity against OS cells in vitro. Aerosolized interleukin 2 (IL-2) administered to dogs with OS lung disease has demonstrated therapeutic benefit. Additionally, Guma S. R. et al. showed that aerosol IL-2 enhanced the efficacy of infused NK cells against OS lung metastasis in vivo. Aerosol IL-2 and NK cell combination therapy resulted in the regression of OS lung metastasis through enhanced tumor cell apoptosis. Moreover, the combination therapy significantly increased the overall survival of mice with OS lung metastases. However, the treatment is not curative as metastasis persists leading to relapse. Recent studies have demonstrated the immunosuppressive role of checkpoint inhibitors such as programmed death receptor 1 (PD-1) and its ligand, programmed death ligand 1 (PDL-1). Inhibition of the PD-1/PDL-1 pathway has shown immunotherapeutic benefit in lung and renal tumors. Involvement of this pathway in OS lung metastases is unknown. Therefore, based on our previous studies of aerosol IL-2, we hypothesize that aerosol IL-2 causes upregulation of PDL-1 expression on OS tumor cells, which in turn interacts with PD-1 receptor on NK cells, restricting NK cells' killing ability against OS. Our preliminary data demonstrates high PDL-1 expression in human OS cells and OS lung metastases from patients. Using a human OS mouse model, we further show that aerosol IL-2 enhances PDL-1 expression in OS lung metastases. PDL-1 expression on OS lung nodules was observed towards the tumor periphery. Hence, we propose that targeting the PD-1/ PDL-1 axis using anti-PD-1 antibody will enhance the efficacy of NK cell-directed therapy, in the presence or absence of IL-2, against OS lung metastasis and improve the overall survival.

Citation Format: Pooja M. Dhupkar, Eugenie Kleinerman, Nancy Gordon. Immune modulation of natural killer cell adoptive transfer for the treatment of Osteosarcoma lung metastastasis: Targeting the PD-1/ PDL-1 signaling pathway. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr A65.

Abstract 2905: HSP27 as a potential factor to determine the fate of Gemcitabine- induced autophagy in osteosarcoma: Survival vs. death

Lung metastasis constitutes the main cause of death in osteosarcoma (OS) patients. Survival has not improved in the past ten years. Therefore, new therapeutic strategies are needed. We previously reported that aerosol Gemcitabine (GCB) has a significant therapeutic effect against OS lung metastases. There was however, a subset of cells that fail to respond to GCB treatment resulting in persistent small isolated lung metastases that led to relapse and death. The mechanisms underlying OS resistance to GCB have remained elusive. Autophagy, a catabolic process involved in cellular homeostasis, has emerged as an important mechanism involved in cancer cells response to treatment. However, whether autophagy plays a role in OS resistance to GCB is unknown. Thus, the purpose of this study is to investigate the role of autophagy in OS lung metastases resistance to GCB. In this study, LM7 and CCH-OS-D human OS cells were treated with GCB and induction of autophagy was evaluated. GCB-induced autophagy was demonstrated by formation of acidic vesicular organelles (AVOs), conversion of microtubule-associated light chain 3 (LC3I/LC3II), increase in Beclin 1 (BECN1) and decrease in p62/SQSTM1 protein expression. Additionally, formation of autophagic vacuoles was confirmed by electron microscopy. GCB-induced autophagy also resulted in the inhibition of AKT /mTOR phosphorylation, suggesting this signaling pathway as a possible underlying mechanism responsible for GCB-induced autophagy in OS. To test whether autophagy contributes to OS cells survival to GCB, we determined the impact of autophagy inhibition on the sensitivity of OS cells to GCB. Sensitivity of LM7 cells to GCB was greatly enhanced after autophagy inhibition by the pharmacologic inhibitor hydroxychloroquine (HCQ) and shRNA targeting BECN1, suggesting autophagy as a pro-survival mechanism. Interestingly, inhibition of autophagy in CCH-OS-D cells decreased cell sensitivity to GCB, suggesting that GCB-induced autophagy contributed to cell death. Better understanding of the molecular pathways that govern the process of autophagy will allow identification of new strategies to enhance chemotherapeutic efficacy. Our preliminary work showed that the phosphorylation of Heat Shock protein 27 (HSP27) was significantly higher in GCB-treated LM7 cells when compared to CCH-OS-D GCB-treated cells, indicating a potential role of HSP27 in outlining the role of autophagy in osteosarcoma cells. Taken together, these results suggest that autophagy can be induced by GCB in OS cells and that inhibition of autophagy can lead to either increase or decrease OS cells sensitivity to Gemcitabine.

Citation Format: Janice M. Santiago-O'Farrill, Mario Hollomon, Eugenie Kleinerman, Nancy Gordon. HSP27 as a potential factor to determine the fate of Gemcitabine- induced autophagy in osteosarcoma: Survival vs. death. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2905. doi:10.1158/1538-7445.AM2015-2905

Pediatric patients with refractory central nervous system tumors: experiences of a clinical trial combining bevacizumab and temsirolimus

BACKGROUND

Pre-clinical findings suggest that combination treatment with bevacizumab and temsirolimus could be effective against malignant pediatric central nervous system (CNS) tumors.

PATIENTS AND METHODS

Six pediatric patients were treated as part of a phase I trial with intravenous temsirolimus 25 mg on days 1, 8, 15, and bevacizumab at 5, 10, or 15 mg/kg on day 1 of each 21-day cycle until disease progression or patient withdrawal.

RESULTS

The median patient age was six years (range=3-14 years). The primary diagnoses were glioblastoma multiforme (n=2), medullobalstoma (n=2), pontine glioma (n=1) and ependymoma (n=1). All patients had disease refractory to standard-of-care (2-3 prior systemic therapies). Grade 3 toxicities possibly related to drugs used occurred in two patients: anorexia, nausea, and weight loss in one, and thrombocytopenia and alanine aminotransferase elevation in another. One patient with glioblastoma multiforme achieved a partial response (51% regression) and two patients (with medulloblastoma and pontine glioma) had stable disease for four months or more (20 and 47 weeks, respectively). One other patient (with glioblastoma multiforme) showed 18% tumor regression (duration=12 weeks).

CONCLUSION

The combination of bevacizumab with temsirolimus was well-tolerated and resulted in stable disease of at least four months/partial response in three out of six pediatric patients with chemorefractory CNS tumors.

Mifamurtide in metastatic and recurrent osteosarcoma: a patient access study with pharmacokinetic, pharmacodynamic, and safety assessments

PURPOSE

This non-randomized, patient-access protocol, assessed both safety and efficacy outcomes following liposomal muramyl-tripeptide-phosphatidylethanolamine (L-MTP-PE; mifamurtide) in patients with high-risk, recurrent and/or metastatic osteosarcoma.

METHODS

Patients received mifamurtide 2 mg/m(2) intravenously twice-weekly ×12 weeks, then weekly ×24 weeks with and without chemotherapy. Serum concentration-time profiles were collected. Adverse events within 24 hours of drug administration were classified as infusion-related adverse events (IRAE); other AEs and overall survival (OS) were assessed.

RESULTS

The study began therapy in January 2008; the last patient completed therapy in October 2012. Two hundred five patients were enrolled; median age was 16.0 years and 146/205 (71%) had active disease. Mifamurtide serum concentrations declined rapidly in the first 30 minutes post-infusion, then in a log-linear manner 2-6 hours post-dose; t1/2 was 2 hours. There were no readily apparent relationships between age and BSA-normalized clearance, half-life, or pharmacodynamic effects, supporting the dose of 2 mg/m(2) mifamurtide across the age range. Patients reported 3,679 IRAE after 7,482 mifamurtide infusions. These were very rarely grade 3 or 4 and most commonly included chills + fever or headache + fatigue symptom clusters. One- and 2-year OS was 71.7% and 45.9%. Patients with initial metastatic disease or progression approximated by within 9 months of diagnosis (N = 40) had similar 2-year OS (39.9%) as the entire cohort (45.9%)

CONCLUSIONS

Mifamurtide had a manageable safety profile; PK/PD of mifamurtide in this patient access study was consistent with prior studies. Two-year OS was 45.9%. A randomized clinical trial would be required to definitively determine impact on patient outcomes.

Abstract 4996: Co-stimulation of IL-12 gene delivery plus doxorubicin induces NKG2D-dependent CD8+T cell infiltration to tumors and inhibition of tumor progression

Chemotherapeutic agents were conventionally viewed as agents that can only eradicate tumor cells and have no impact on the immune system. However, recent work has identified a novel function of chemotherapeutic agents, which is to prevent an immunosuppressive effect in the tumor microenvironment and even facilitate the infiltration of immune effector cells into tumors and sensitize tumor cells to immune cell attack. In fact, immune response induced by chemotherapeutic agents may become a predictor of therapeutic outcome in cancer patients. In agreement with these observations, some chemotherapeutic agents when combined with immunotherapy promote anti-tumor immune response, resulting in an improved anti-tumor efficacy. Despite these progress, it remains unclear how to properly and effectively combine immune stimulatory gene therapy and chemotherapy to boost anti-tumor efficacy.

This study reveals upregulation of NKG2D in CD8+T cells may serve as a valuable end point for selecting such a proper immune- and chemo-therapy combination. This conclusion is based on the fact that IL-12 immunogene therapy plus doxorubicin-induced expression of natural killer group 2, member D (NKG2D) in CD8+T cells, increases NKG2D-dependent CD8+T cell localization into tumors and anti-tumor efficacy. This NKG2D upregulation and localization into tumors after the co-stimulation of IL-12 plus doxorubicin is CD8+T cell specific because this observation occurs in wild-type mice and NK deficient mice, but not in T cell deficient mice. The depletion study confirmed this statement because depletion of NK cells did not affect the detection of NKG2D upregulation and NKG2D positive CD8+T cell localization in tumors by the co-stimulation, but depletion of CD8+T cells completely abolish the detection of CD8+T cells in tumor microenvironment subjected to the same stimulation. Consistent with these result, blocking NKG2D receptor using a neutralizing antibody impaired doxorubicin plus IL-12 gene delivery-mediated tumor eradication in vivo and reduced cytolytic activity in vitro.

In summary, we have shown in vivo evidence that Dox plus IL-12 gene delivery induces CD8+T cell-specific NKG2D upregulation. This upregulation facilitates the infiltration of these NKG2D-expressing CD8+T cells into the tumor site. The significance of this study is to elucidate that doxorubicin plus IL-12-induced CD8+T cells infiltrating into tumors is dependent on NKG2D expression and this NKG2D upregulation can be used as an end point for this combination therapy for measuring anti-tumor immune response. Our study is also significant for CAR-based T cell therapy, because our data suggests that IL-12 plus doxorubicin treatment may promote NKG2D-based CAR-T cell therapy by possibly causing tumor specific infiltration.

Citation Format: Jiemiao Hu, Shiguo Zhu, Xueqing Xia, Eugenie Kleinerman, Shulin Li. Co-stimulation of IL-12 gene delivery plus doxorubicin induces NKG2D-dependent CD8+T cell infiltration to tumors and inhibition of tumor progression. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4996. doi:10.1158/1538-7445.AM2013-4996

Abstract 1421: Down-regulation of neuronal repressor gene REST inhibits tumor growth in Ewing's sarcoma

Ewing's sarcoma is a peripheral primitive neuroectodermal tumors (PNET). The abnormal differentiation of neuronal stem cells may relate to tumorigenesis of Ewing's sarcoma. The RE1-silencing transcription factor (REST) is a neuronal repressor gene which regulates neuronal stem cell differentiation. The aim of this study is to investigate the role of REST in Ewing's sarcoma. Our results demonstrated that three human Ewing's sarcoma cell lines TC71, A4573 and SK-ES expressed high levels of REST. Six of seven tumor samples from patients with Ewing's sarcoma were shown REST positive. Transfection of EWS-FLI-1 into mesenchymal stem cells up-regulated REST expression. Down-regulation of EWS-FLI-1 using si-RNA inhibited REST expression in TC71 cells, suggesting EWS-FLI-1 fusion protein regulates REST expression in Ewing's sarcoma. The siRNA-REST stable transfected cell line was established to down-regulate REST expression in TC71 Ewing's sarcoma cells. In vivo experiments indicated that Ewing's sarcoma tumor growth was significantly inhibited in the mice injected with si-REST-TC71 cells compared to the mice injected with si-control cells. Down-regulation of REST inhibited cell proliferation and induced apoptosis in TC71 tumors. The immunohistochemical staining indicated that the tumor vessels and pericyte marker expression were reduced in si-REST tumor tissues. Inhibition of REST decreased the early neural differentiation marker MSX-1 expression and up-regulated the terminal neural differentiation marker β-Tubulin III (Tuj) expression. These data suggesting that neuronal repressor gene REST plays an important role in tumor development of Ewing's sarcoma. Inhibition of REST suppressed tumor growth and altered neuronal differentiation marker expression in Ewing's sarcoma. REST is a potential target for treatment of Ewing's sarcoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1421. doi:1538-7445.AM2012-1421

Aerosol gemcitabine: preclinical safety and in vivo antitumor activity in osteosarcoma-bearing dogs

BACKGROUND

Osteosarcoma is the most common skeletal malignancy in the dog and in young humans. Although chemotherapy improves survival time, death continues to be attributed to metastases. Aerosol delivery can provide a strategy with which to improve the lung drug delivery while reducing systemic toxicity. The purpose of this study is to assess the safety of a regional aerosol approach to chemotherapy delivery in osteosarcoma-bearing dogs, and second, to evaluate the effect of gemcitabine on Fas expression in the pulmonary metastasis.

METHODS

We examined the systemic and local effects of aerosol gemcitabine on lung and pulmonary metastasis in this relevant large-animal tumor model using serial laboratory and arterial blood gas analysis and histopathology and immunohistochemistry, respectively.

RESULTS AND CONCLUSIONS

Six hundred seventy-two 1-h doses of aerosol gemcitabine were delivered. The treatment was well tolerated by these subjects with osteosarcoma (n = 20). Aerosol-treated subjects had metastatic foci that demonstrated extensive, predominately central, intratumoral necrosis. Fas expression was decreased in pulmonary metastases compared to the primary tumor (p = 0.008). After aerosol gemcitabine Fas expression in the metastatic foci was increased compared to lung metastases before treatment (p = 0.0075), and even was higher than the primary tumor (p = 0.025). Increased apoptosis (TUNEL) staining was also detected in aerosol gemcitabine treated metastasis compared to untreated controls (p = 0.028). The results from this pivotal translational study support the concept that aerosol gemcitabine may be useful against pulmonary metastases of osteosarcoma. Additional studies that evaluate the aerosol route of administration of gemcitabine in humans should be safe and are warranted.

Inhibiting platelet-derived growth factor beta reduces Ewing's sarcoma growth and metastasis in a novel orthotopic human xenograft model

BACKGROUND

Despite aggressive therapy, Ewing's sarcoma (ES) patients have a poor five-year overall survival of only 20-40%. Pulmonary metastasis is the most common form of demise in these patients. The pathogenesis of pulmonary metastasis is poorly understood and few orthotopic models exist that allow study of spontaneous pulmonary metastasis in ES.

MATERIALS AND METHODS

We have developed a novel orthotopic xenograft model in which spontaneous pulmonary metastases develop. While the underlying biology of ES is incompletely understood, in addition to the EWS-FLI-1 mutation, it is known that platelet-derived growth factor receptor beta (PDGFR-beta) is highly expressed in ES. Hypothesizing that PDGFR-beta expression is indicative of a specific role for this receptor protein in ES progression, the effect of PDGFR-beta inhibition on ES growth and metastasis was assessed in this novel orthotopic ES model.

RESULTS

Silencing PDGFR-beta reduced spontaneous growth and metastasis in ES.

CONCLUSION

Preclinical therapeutically relevant findings such as these may ultimately lead to new treatment initiatives in ES.

Osteosarcoma: the addition of muramyl tripeptide to chemotherapy improves overall survival--a report from the Children's Oncology Group

PURPOSE

To compare three-drug chemotherapy with cisplatin, doxorubicin, and methotrexate with four-drug chemotherapy with cisplatin, doxorubicin, methotrexate, and ifosfamide for the treatment of osteosarcoma. To determine whether the addition of muramyl tripeptide (MTP) to chemotherapy enhances event-free survival (EFS) and overall survival in newly diagnosed patients with osteosarcoma.

PATIENTS AND METHODS

Six hundred sixty-two patients with osteosarcoma without clinically detectable metastatic disease and whose disease was considered resectable received one of four prospectively randomized treatments. All patients received identical cumulative doses of cisplatin, doxorubicin, and methotrexate and underwent definitive surgical resection of primary tumor. Patients were randomly assigned to receive or not to receive ifosfamide and/or MTP in a 2 x 2 factorial design. The primary end points for analysis were EFS and overall survival.

RESULTS

In the current analysis, there was no evidence of interaction, and we were able to examine each intervention separately. The chemotherapy regimens resulted in similar EFS and overall survival. There was a trend toward better EFS with the addition of MTP (P = .08). The addition of MTP to chemotherapy improved 6-year overall survival from 70% to 78% (P = .03). The hazard ratio for overall survival with the addition of MTP was 0.71 (95% CI, 0.52 to 0.96).

CONCLUSION

The addition of ifosfamide to cisplatin, doxorubicin, and methotrexate did not enhance EFS or overall survival for patients with osteosarcoma. The addition of MTP to chemotherapy resulted in a statistically significant improvement in overall survival and a trend toward better EFS.

Biology of childhood osteogenic sarcoma and potential targets for therapeutic development: meeting summary

Childhood osteogenic sarcoma (OS) is a rare bone cancer occurring primarily in adolescents. The North American pediatric cooperative groups have performed a series of clinical treatment trials in this disease over the past several decades, and biology studies of tumor tissue have been an important study component. A meeting was held in Bethesda, Maryland on November 29-30, 2001, sponsored by the NIH Office of Rare Diseases, the Children's Oncology Group, and the National Cancer Institute-Cancer Therapy Evaluation Program with the general objectives: (a) to review the current state of knowledge regarding OS biology; (b) to identify, prioritize, and support the development of biology studies of potential clinical relevance in OS; and (c) to discuss the available tissue resources and the appropriate methods for analysis of OS samples for the conduct of biology studies. This report summarizes the information presented and discussed by the meeting participants.

Anti-cancer activity of 9-nitrocamptothecin liposome aerosol in mice

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Metastatic epidural osteosarcoma initially diagnosed as cisplatin neuropathy

Unexpected early epidural spinal metastasis in a case of osteosarcoma occurred in a patient receiving treatment with cis-diamminedichloroplatinum-II (cisplatin). The initial neurologic symptomatology manifested as paresthesias in the feet which developed 2 months after initiation of treatment (cumulative dose of cisplatin 450 mg/M2) at which stage the primary tumor demonstrated a marked response. Concurrently two small pulmonary metastases appeared. Epidural metastasis in osteosarcoma is generally considered a late complication and is usually associated with disseminated disease. This communication draws attention to changes in the metastatic pattern which may occur with the administration of seemingly effective treatment and the potential for confusing the symptomatology of epidural spinal metastasis with cisplatin neuropathy.

Ultrastructural studies of the interaction between liposome-activated human blood monocytes and allogeneic tumor cells in vitro

Human blood monocytes were activated to become tumoricidal by incubation with liposomes containing muramyl tripeptide-phosphatidylethanolamine, a lipophilic derivative of muramyl dipeptide. The interaction of both tumoricidal and control monocytes with target melanoma cells was analyzed by means of light microscopy and scanning and transmission electron microscopy. The authors found increased clustering around the melanoma cells by tumoricidal monocytes as compared with the control monocytes. The initial clustering of the tumoricidal monocytes around the tumor cells was followed by the establishment of numerous focal points of contact (binding), some of which actually exhibited areas of discontinuous membrane, a finding confirmed by stereophotography. By 24-48 hours of cocultivation, many of the target cells exhibited zones of vacuolation in the immediate vicinity of the tumoricidal monocytes, suggesting target cell damage. (This finding was confirmed by time-course cytotoxicity assays.) The authors conclude that tumor cell lysis mediated by activated human blood monocytes occurs as the final step in a process that includes the establishment of a direct cell-cell contact, damage to the target cell membrane, and the development of areas of vacuolation in the target cells.