Faculty Bibliography

BACKGROUND: H3 K27M-mutant gliomas have a dismal clinical prognosis and no proven curative therapy. We report the updated clinical experience with ONC201, the first cancer-specific DRD2 antagonist, in adult and pediatric H3 K27M-mutant gliomas.
METHOD(S): As of May 28, 2018, 26 patients with H3 K27M-mutant glioma have been treated with ONC201: 9 pediatric (<18 years old) and 17 adult patients (>18 years old). Twelve patients had recurrent disease and 14 had previously-treated stable disease prior to initiating ONC201. Patients had 1-4 prior lines of therapy and all received prior radiation. Ten adult patients were enrolled on clinical trials and the other 16 were on compassionate use. ONC201 was orally administered at 625 mg to adults and scaled by body weight for pediatric patients. All patients, except one, were dosed weekly.
RESULT(S): Fourteen of 26 patients (54%) remain progression-free on ONC201 with a median follow up of 3.6 (range 1.6-24.5) months. No dose modifications or discontinuation due to toxicity have occurred. Among the 12 adult patients with recurrent disease who received single agent ONC201, the estimated PFS6 is 36.5%. Seven patients have experienced radiographic and/or clinical benefit (neurological stabilization or improvement). Among the 5 adults with recurrent thalamic glioma, three have experienced durable complete regression of their thalamic tumors, including the first H3 K27M-mutant glioma patient treated with ONC201 who has experienced 96% regression of her recurrent disease and continues single agent ONC201 for >2 years. Two DIPG pediatric patients who initiated single agent ONC201 6-8 weeks after radiation have experienced radiographic and neurological improvements and exhibited PFS of >13 months from diagnosis.
CONCLUSION(S): Emerging clinical data suggest that ONC201 exhibits clinical activity for some patients with H3 K27M-mutant glioma

Patients have received experimental pharmaceuticals outside of clinical trials for decades. There are no industry-wide best practices, and many companies that have granted compassionate use, or 'preapproval', access to their investigational products have done so without fanfare and without divulging the process or grounds on which decisions were made. The number of compassionate use requests has increased over time. Driving the demand are new treatments for serious unmet medical needs; patient advocacy groups pressing for access to emerging treatments; internet platforms enabling broad awareness of compelling cases or novel drugs and a lack of trust among some that the pharmaceutical industry and/or the FDA have patients' best interests in mind. High-profile cases in the media have highlighted the gap between patient expectations for compassionate use and company utilisation of fair processes to adjudicate requests. With many pharmaceutical manufacturers, patient groups, healthcare providers and policy analysts unhappy with the inequities of the status quo, fairer and more ethical management of compassionate use requests was needed. This paper reports on a novel collaboration between a pharmaceutical company and an academic medical ethics department that led to the formation of the Compassionate Use Advisory Committee (CompAC). Comprising medical experts, bioethicists and patient representatives, CompAC established an ethical framework for the allocation of a scarce investigational oncology agent to single patients requesting non-trial access. This is the first account of how the committee was formed and how it built an ethical framework and put it into practice.

The imipridone ONC201 is the first selective antagonist of DRD2 for clinical oncology. Several Phase 1, Phase 1/2 and Phase 2 studies in patients with advanced cancers have established the single agent recommended Phase 2 dose (RP2D) of 625mg ONC201 administered orally once a week in adults. ONC201 induces p53-independent apoptosis in newly diagnosed and recurrent high-grade glioma in vitro, ex vivo and in vivo. Furthermore, radiographic regressions in adult recurrent H3 K27M-mutant glioblastoma patients in response to single agent ONC201 have been reported. Based on this adult experience and complementary preclinical results demonstrating the increased susceptibility of H3 K27M-mutant gliomas to ONC201, we initiated the first Phase 1 pediatric clinical trial of ONC201 January 30, 2018. This trial will determine the safety and RP2D of ONC201 in pediatric postradiation H3 K27M-mutant glioma patients as a single agent and in newly diagnosed diffuse intrinsic pontine glioma (DIPG) patients in combination with radiation (NCT03416530). Patients without known H3 K27M-mutation status by a CLIA-lab can enroll with commitment to post-term biopsy. This is a multicenter, open-label, 2 arm, dose-escalation and dose-expansion study. Ten children with H3 K27M-mutant gliomas ages 5-18 years have been treated post-radiation: 3 at dose level 1; 3 at dose level 2; 4 as part of the dose expansion cohort on dose level 2. Patients have received 2-12 doses (median= 5). The ONC201 has been tolerated very well. Grade III/IV events include: decreased neutrophil count grade III (n=1) spontaneously resolved without dose modification and elevated AST grade III (n=1) returned to grade II after holding 1 dose. Additional safety data as well as pharmacokinetics, pharmacodynamics, and progression-free survival results from this trial will be reported

Background/UNASSIGNED:Diagnosis of diffuse intrinsic pontine glioma (DIPG) has relied on imaging studies, since the appearance is pathognomonic, and surgical risk was felt to be high and unlikely to affect therapy. The DIPG Biology and Treatment Study (DIPG-BATS) reported here incorporated a surgical biopsy at presentation and stratified subjects to receive FDA-approved agents chosen on the basis of specific biologic targets. Methods/UNASSIGNED:Subjects were eligible for the trial if the clinical features and imaging appearance of a newly diagnosed tumor were consistent with a DIPG. Surgical biopsies were performed after enrollment and prior to definitive treatment. All subjects were treated with conventional external beam radiotherapy with bevacizumab, and then stratified to receive bevacizumab with erlotinib or temozolomide, both agents, or neither agent, based on O6-methylguanine-DNA methyltransferase status and epidermal growth factor receptor expression. Whole-genome sequencing and RNA sequencing were performed but not used for treatment assignment. Results/UNASSIGNED:Fifty-three patients were enrolled at 23 institutions, and 50 underwent biopsy. The median age was 6.4 years, with 24 male and 29 female subjects. Surgical biopsies were performed with a specified technique and no deaths were attributed to the procedure. Two subjects experienced grade 3 toxicities during the procedure (apnea, n = 1; hypertension, n = 1). One subject experienced a neurologic deficit (left hemiparesis) that did not fully recover. Of the 50 tumors biopsied, 46 provided sufficient tissue to perform the study assays (92%, two-stage exact binomial 90% CI: 83%-97%). Conclusions/UNASSIGNED:Surgical biopsy of DIPGs is technically feasible, associated with acceptable risks, and can provide biologic data that can inform treatment decisions.

Pineoblastoma is a rare and highly aggressive brain cancer of childhood, histologically belonging to the spectrum of primitive neuroectodermal tumors. Patients with germline mutations in DICER1, a ribonuclease involved in microRNA processing, have increased risk of pineoblastoma, but genetic drivers of sporadic pineoblastoma remain unknown. Here, we analyzed pediatric and adult pineoblastoma samples (n = 23) using a combination of genome-wide DNA methylation profiling and whole-exome sequencing or whole-genome sequencing. Pediatric and adult pineoblastomas showed distinct methylation profiles, the latter clustering with lower-grade pineal tumors and normal pineal gland. Recurrent variants were found in genes involved in PKA- and NF-κB signaling, as well as in chromatin remodeling genes. We identified recurrent homozygous deletions of DROSHA, acting upstream of DICER1 in microRNA processing, and a novel microduplication involving chromosomal region 1q21 containing PDE4DIP (myomegalin), comprising the ancient DUF1220 protein domain. Expresion of PDE4DIP and DUF1220 proteins was present exclusively in pineoblastoma with PDE4DIP gain.

Although radiotherapy is the mainstay of treatment for children with diffuse intrinsic pontine gliomas (DIPG), fewer than 10% of patients survive past two years from diagnosis despite 30 years of clinical trials. ONC201 is an oral, selective DRD2 antagonist that induces p53-independent apoptosis and has been reported to produce a durable response in an adult with a H3 K27M mutant recurrent glioblastoma. In April 2017, a 33 month old female presented with headaches, right 6th nerve palsy and MRI findings consistent with a DIPG. A biopsy revealed an H3.3 K27M mutant glioblastoma. A patient-derived DIPG tumorsphere cell line was created from the biopsy sample and in vitro studies revealed a potent reduction in cell viability following 5 days of treatment with ONC201, with an IC50 of approximately 600nM. She received involved field irradiation (54Gy). Starting one month following irradiation, single agent, oral ONC201 125mg (11mg/kg) was given weekly on a compassionate use protocol. An MRI, 4 months later revealed stable disease. Clinically, her 6th nerve palsy and left hemiparesis have improved. She is otherwise asymptomatic. Pharmacokinetic studies are being analyzed. She has had no side effects detected. Based on our in vitro and clinical findings as well as other experience in vitro and in adults, ONC201 is currently being investigated with a phase 1 trial in pediatric patients with H3 K27M mutant gliomas

BACKGROUND: Pineoblastoma is a rare and highly aggressive brain cancer of childhood, histologically belonging to the spectrum of primitive neuroectodermal tumors. Patients with germline mutations in DICER1, a ribonuclease involved in microRNA processing, have increased risk of pineoblastoma, but genetic drivers of sporadic pineoblastoma remain unknown. METHODS: We analyzed pediatric and adult pineoblastoma samples (n=23) using integrated genomic studies, including genome-wide DNA methylation profiling, whole-exome or whole-genome sequencing, and whole-transcriptome analysis. RESULTS: Pediatric and adult pineoblastomas showed distinct methylation profiles, the latter clustering with lower grade pineal tumors and normal pineal gland. Recurrent somatic mutations were found in genes involved in PKA-and NF-kappaB signaling, as well as in chromatin remodeling genes. We identified recurrent homozygous deletions of DROSHA, acting upstream of DICER1 in microRNA processing, and a novel microduplication involving chromosomal region 1q21 containing PDE4DIP (myomegalin), comprising the ancient DUF1220 protein domain. Expression of PDE4DIP and DUF1220 proteins was present exclusively in pineoblastoma with PDE4DIP gain. Whole-transcriptome analysis showed that homozygous loss of DROSHA led to distinct changes in RNA expression profile. Disruption of the DROSHA locus in human neural stem cells using the CRISPR/Cas9 system, led to decrease of the DROSHA protein, and massive loss of miRNAs. CONCLUSION: We identified recurrent homozygous deletions of DROSHA in pineoblastoma, suggesting that different mechanisms disrupting miRNA processing are involved in the pathogenesis of familial versus sporadic pineoblastoma. Furthermore, a novel microduplication of PDE4DIP leading to upregulation of DUF1220 protein suggests DUF1220 as a novel oncogenic driver in pineoblastoma

INTRODUCTION: Liquid biopsy has the potential to revolutionize diagnosis and management of cancer. In brain tumors, detection of cell free tumor DNA (ctDNA) and circulating tumor cells (CTC) is challenging due to low level of the circulating material. We present a novel workflow for detection and capture of CTCs. METHODS: Peripheral blood was obtained from five pediatric patients with astrocytoma (n=2), ependymoma (n=1), dysembryoplastic neuroepithelial tumor (n=1), and medulloblastoma (n=1) at initial resection (n=3) and relapse (n=2). Samples were enriched using the Clear-Bridge ClearCell FX1 system and the suspension stained with antibodies against CD56 and CD45. Samples were analyzed using Silicon Biosystems DEPArray to capture single and pooled CTCs. CTCs were identified by CD56 positivity, while leukocytes were positive for CD45 and NK cells double-positive for CD56 and CD45. RESULTS: CTCs were identified in all 5 patient samples. The number of CD56-positive cells isolated from each sample ranged from 1 to 25 (mean 9). The CD56-positive cells were on average 11.8 mum in diameter (range 9.0-15.7 mum), and CD45-positive cells were on average 10.8 mum in diameter (range 8.9-15.9 mum). Single CTCs and CTC pools are amenable to molecular analysis after whole genome amplification. CONCLUSION: We report a novel integrated workflow for capturing CTCs in pediatric patients with brain tumors. While rare, CTCs circulate in peripheral blood of patients with brain tumors regardless of their grade and are amenable for molecular analysis. This method has the potential to serve as a non-invasive diagnostic and monitoring method for pediatric brain tumors