Prolonged Survival Using Outpatient Palliative Chemotherapy in Two Children With Refractory Acute Myelogenous Leukemia.

BACKGROUND: Therapy options for relapsed/refractory acute myelogenous leukemia (AML) are limited. Palliative chemotherapy options have been explored in adult patients, but little evidence exists in children. OBJECTIVES: Describe the clinical course of 2 pediatric patients with refractory AML who transitioned to outpatient palliative chemotherapy with good disease control and quality of life on these regimens. PATIENTS AND METHODS: Patient 1 was a 2-year-old girl who received a total of 4 cycles of standard chemotherapy with multiple complications and 15% to 20% blasts on marrow subsequent evaluation. An outpatient regimen of decitabine and vorinostat was consequently chosen for her. Patient 2 was a 16-year-old boy with residual disease after induction 1 with arm A with cytarabine, daunorubicin, and etoposide. His induction 2 course was complicated by multiorgan failure secondary to multiple infections including Klebsiella pneumonia and radiographically identified pulmonary fungal disease. On recovery, the marrow showed no disease but after the toxicities of initial therapy, the patient pursued a palliative regimen with azacitidine and lenalidomide. RESULTS: Patient 1 tolerated her regimen for 14 months, requiring weekly blood products and only one hospitalization for a central-line infection. Her blast count then increased precipitously, the disease progressed, and she died comfortably while receiving hospital-based end-of-life care. Patient 2 tolerated 14 months of his regimen. On a surveillance marrow sample, he was found to have 0.02% minimal residual disease. He then elected to pursue marrow transplantation. He maintained remission until his 6-month posttransplant surveillance bone marrow biopsy, which revealed 0.04% minimal residual disease. CONCLUSION: We describe 2 pediatric patients with relapsed/refractory AML who achieved disease control and acceptable quality of life utilizing outpatient palliative chemotherapy for over 12 months. These regimens should be considered in patients who no longer desire cytotoxic chemotherapy or are ineligible for further aggressive approaches.

Novel combination of imipridones and histone deacetylase inhibitors demonstrate cytotoxic effect through integrated stress response in pediatric solid tumors.

There is a demonstrated need for new chemotherapy options in pediatric oncology, as pediatric solid tumors continue to plateau at 60% with event-free survival. Imipridones, a novel class of small molecules, represent a potential new therapeutic option, with promising pre-clinical data and emerging clinical trial data in adult malignancies. ONC201, ONC206, and ONC212 are imipridones showing pro-apoptotic anti-cancer response. Using cell viability assays, and protein immunoblotting, we were able to demonstrate single-agent efficacy of all 3 imipridones inducing cell death in pediatric solid tumor cell lines, including osteosarcoma, malignant peripheral nerve sheath tumors, Ewing sarcoma (EWS), and neuroblastoma. ONC201 displayed IC50 values for non-H3K27M-mutated EWS cell lines ranging from 0.86 µM (SK-N-MC) to 2.76 µM (RD-ES), which were comparable to the range of IC50 values for H3K27M-mutated DIPG cells lines (range 1.06 to 1.56 µM). ONC212 demonstrated the highest potency in single-agent cell killing, followed by ONC206, and ONC201. Additionally, pediatric solid tumor cells were treated with single-agent therapy with histone deacetylase inhibitors (HDACi) vorinostat, entinostat, and panobinostat, showing cell killing with all 3 HDACi drugs, with panobinostat showing the greatest potency. We demonstrate that dual-agent therapy with combinations of imipridones and HDACi lead to synergistic cell killing and apoptosis in all pediatric solid tumor cell lines tested, with ONC212 and panobinostat combinations demonstrating maximal potency. The imipridones induced the integrated stress response with ATF4 and TRAIL receptor upregulation, as well as reduced expression of ClpX. Hyperacetylation of H3K27 was associated with synergistic killing of tumor cells following exposure to imipridone plus HDAC inhibitor therapies. Our results introduce a novel class of small molecules to treat pediatric solid tumors in a precision medicine framework. Use of impridones in pediatric oncology is novel and shows promising pre-clinical efficacy in pediatric solid tumors, including in combination with HDAC inhibitors.

Potent preclinical sensitivity to imipridone-based combination therapies in oncohistone H3K27M-mutant diffuse intrinsic pontine glioma is associated with induction of the integrated stress response, TRAIL death receptor DR5, reduced ClpX and apoptosis.

The H3K27M oncohistone mutation, identified in approximately 80% of diffuse intrinsic pontine gliomas (DIPG), is a potential target for therapy. Imipridone ONC201/TIC10 (TRAIL-Inducing Compound #10) induces apoptosis of cancer cells, and has clinical efficacy against H3K27M-mutant DIPG. We demonstrate synergy between ONC201, ONC206 and ONC212, and targeted therapies with known preclinical activity against DIPG. We hypothesized that imipridone combinations with HDAC or proteasome inhibitors may be superior to single agent ONC201 treatment in H3K27M mutant DIPG. Six patient-derived DIPG cell lines (SU-DIPG-IV, SU-DIPG-13, SU-DIPG-25, SU-DIPG-27, SU-DIPG-29, SU-DIPG-36) were exposed to imipridones alone or combinations with histone de-acetylase inhibitors [HDACi], marizomib, etoposide, and temozolomide. Dose-dependent response to imipridones was observed in DIPG cells with half-maximal inhibitory concentration (IC50) of 1.46 µM, 0.11 µM, and 0.03 µM, for ONC201, ONC206, and ONC212, respectively. Upon treatment with the imipridones, DIPG cell lines engaged CLpP/CLPX, the integrated stress response with ATF4 activation, and TRAIL death receptor 5 (DR5) induction. Strong synergy was identified between ONC201 and HDACi panobinostat (combination index [CI] 0.01), romidepsin (CI 0.08) and proteasome inhibitor marizomib (CI 0.19). Synergy was demonstrated between ONC201 and etoposide (CI 0.54), although to a lesser degree than with panobinostat, romidepsin, and marizomib. ONC206 and ONC212 showed similar synergistic effects with panobinostat, romidepsin, and marizomib. Induction of apoptosis was demonstrated with imipridones and panobinostat or romidepsin combinations. Our results suggest increased sensitivity of H3K27M-mutant DIPG cell lines to second generation imipridone therapies, as compared to ONC201. Additionally, there is synergistic cell death with combination of imipridones and panobinostat, romidepsin, or marizomib, which may be further tested in vivo and in clinical trials.

Molecular Targets for Novel Therapeutics in Pediatric Fusion-Positive Non-CNS Solid Tumors.

Chromosomal fusions encoding novel molecular drivers have been identified in several solid tumors, and in recent years the identification of such pathogenetic events in tumor specimens has become clinically actionable. Pediatric sarcomas and other rare tumors that occur in children as well as adults are a group of heterogeneous tumors often with driver gene fusions for which some therapeutics have already been developed and approved, and others where there is opportunity for progress and innovation to impact on patient outcomes. We review the chromosomal rearrangements that represent oncogenic events in pediatric solid tumors outside of the central nervous system (CNS), such as Ewing Sarcoma, Rhabdomyosarcoma, Fibrolamellar Hepatocellular Carcinoma, and Renal Cell Carcinoma, among others. Various therapeutics such as CDK4/6, FGFR, ALK, VEGF, EGFR, PDGFR, NTRK, PARP, mTOR, BRAF, IGF1R, HDAC inhibitors are being explored among other novel therapeutic strategies such as ONC201/TIC10.

ONC201 and imipridones: Anti-cancer compounds with clinical efficacy.

ONC201 was originally discovered as TNF-Related Apoptosis Inducing Ligand (TRAIL)-inducing compound TIC10. ONC201 appears to act as a selective antagonist of the G protein coupled receptor (GPCR) dopamine receptor D2 (DRD2), and as an allosteric agonist of mitochondrial protease caseinolytic protease P (ClpP). Downstream of target engagement, ONC201 activates the ATF4/CHOP-mediated integrated stress response leading to TRAIL/Death Receptor 5 (DR5) activation, inhibits oxidative phosphorylation via c-myc, and inactivates Akt/ERK signaling in tumor cells. This typically results in DR5/TRAIL-mediated apoptosis of tumor cells; however, DR5/TRAIL-independent apoptosis, cell cycle arrest, or antiproliferative effects also occur. The effects of ONC201 extend beyond bulk tumor cells to include cancer stem cells, cancer associated fibroblasts and immune cells within the tumor microenvironment that can contribute to its efficacy. ONC201 is orally administered, crosses the intact blood brain barrier, and is under evaluation in clinical trials in patients with advanced solid tumors and hematological malignancies. ONC201 has single agent clinical activity in tumor types that are enriched for DRD2 and/or ClpP expression including specific subtypes of high-grade glioma, endometrial cancer, prostate cancer, mantle cell lymphoma, and adrenal tumors. Synergy with radiation, chemotherapy, targeted therapy and immune-checkpoint agents has been identified in preclinical models and is being evaluated in clinical trials. Structure-activity relationships based on the core pharmacophore of ONC201, termed the imipridone scaffold, revealed novel potent compounds that are being developed. Imipridones represent a novel approach to therapeutically target previously undruggable GPCRs, ClpP, and innate immune pathways in oncology.

A turn-on fluorescence chemosensor based on a tripodal amine [tris(pyrrolyl-α-methyl)amine]-rhodamine conjugate for the selective detection of zinc ions.

A novel tetradendate ligand derived from a tris(pyrrolyl-α-methyl)amine (H3tpa) and rhodamine-based conjugate (PR) has been designed for use as a sensor, synthesized and characterized spectroscopically. PR {(tris(5-rhodamineiminopyrrol-2-ylmethyl)amine)} serves as a selective colorimetric as well as a fluorescent chemosensor for Zn(2+) in acetonitrile/water (1 : 1, v/v). In the presence of Zn(2+), PR exhibited obvious absorption (558 nm) and emission (577 nm) peaks whose intensity increased along with increasing Zn(2+) concentrations. Titration experiments revealed that a large excess of Zn(2+) was required to saturate the absorption (λmax) and emission intensities. Upon the addition of 1000 equivalents of Zn(2+), the fluorescence intensity of the PR underwent an ∼500-fold increase (Φf = 0.34) with the emission maximum at 580 nm. These kinetics studies demonstrated that the absorption and emission changes were proportional to the Zn(2+) concentration. The color of the solution changed from colorless to a dark pink color. The fluorescence of the PR-Zn(2+) complex can be reversibly restored by using ammonium water or by heating. Competitive ion tests revealed that the intensity of PR-Zn(2+) was not suppressed by excess amounts of other metal ions. The counter anions did not exert obvious influences on the absorption and emission profiles. (1)H-NMR and FT-IR spectroscopic investigations of PR and PR-Zn(2+) revealed that the pyrrole motifs, -C[double bond, length as m-dash]N- groups and spirolactam of rhodamine B are capable of coordinating cation guest species. Because each arm of the tripodal ligand tautomerizes independently, only moderate fluorescence enhancement could be seen until all three -C[double bond, length as m-dash]N- groups were coordinated by zinc, which may be due to the spirolactam ring opening mechanism of the rhodamine unit. Once all three -C[double bond, length as m-dash]N- groups were locked by coordinating with excess of Zn(2+), the isomerization was arrested, and PR exhibited highly enhanced fluorescence. In addition, energy optimized structures of PR were found to be cage-like by Gaussian 09, further supporting that it can access a large excess of Zn(2+). Intriguingly, imaging of HeLa cells by using a confocal microscope revealed that this PR probe could be used for biological applications.

Role of metastasectomy in the management of thyroid carcinoma: the NIH experience.

BACKGROUND AND OBJECTIVES: We studied the impact of metatasectomy on disease outcome in 29 advanced nonmedullary thyroid carcinoma (ThyrCa) patients who were operated on between 1969 and 2001 at NIH to further define its role in the management of this malignancy. METHODS: Data were extracted by retrospective chart review. A Kaplan-Meyer survival curve was constructed, and comparative stratification for various parameters was performed. RESULTS: During 47 surgeries, the following lesions were resected from mid-mediastinum/hila, 17; lung parenchyma, 12; skeleton, 14; kidneys, 2; and brain, 2. All patients received multiple radioiodine (RAI) treatments. External-beam radiotherapy, chemotherapy and other palliative measures were used in selected patients. Six patients (21%) died within 74.7 +/- 54.7 months after the first distant metastasectomy. The outcome of the remaining patients was as follows: complete remission, 3; partial remission, 10; and 10: progressive disease, 10, with a follow-up of 175 patient-years. Metastasectomy led to a decrease of 38% in thyroglobulin levels in 23 patients. Cumulative survival rates were 78.5 +/- 8.4% at 5 years and 50.2 +/- 12.5% at 10 years (mean +/-SEM) after initial distant metastasectomy. CONCLUSIONS: Our data show that extensive targeted metastasectomy in the setting of a tertiary center can be beneficial to patients with disseminated ThyrCa with persistent or recurrent distant disease, when used in conjunction with nonsurgical treatment modalities.