A road map for the treatment of pediatric diffuse midline glioma.

Recent clinical trials for H3K27-altered diffuse midline gliomas (DMGs) have shown much promise. We present a consensus roadmap and identify three major barriers: (1) refinement of experimental models to include immune and brain-specific components; (2) collaboration among researchers, clinicians, and industry to integrate patient-derived data through sharing, transparency, and regulatory considerations; and (3) streamlining clinical efforts including biopsy, CNS-drug delivery, endpoint determination, and response monitoring. We highlight the importance of comprehensive collaboration to advance the understanding, diagnostics, and therapeutics for DMGs.

Clinical Efficacy of ONC201 in H3K27M-Mutant Diffuse Midline Gliomas Is Driven by Disruption of Integrated Metabolic and Epigenetic Pathways.

Patients with H3K27M-mutant diffuse midline glioma (DMG) have no proven effective therapies. ONC201 has recently demonstrated efficacy in these patients, but the mechanism behind this finding remains unknown. We assessed clinical outcomes, tumor sequencing, and tissue/cerebrospinal fluid (CSF) correlate samples from patients treated in two completed multisite clinical studies. Patients treated with ONC201 following initial radiation but prior to recurrence demonstrated a median overall survival of 21.7 months, whereas those treated after recurrence had a median overall survival of 9.3 months. Radiographic response was associated with increased expression of key tricarboxylic acid cycle-related genes in baseline tumor sequencing. ONC201 treatment increased 2-hydroxyglutarate levels in cultured H3K27M-DMG cells and patient CSF samples. This corresponded with increases in repressive H3K27me3 in vitro and in human tumors accompanied by epigenetic downregulation of cell cycle regulation and neuroglial differentiation genes. Overall, ONC201 demonstrates efficacy in H3K27M-DMG by disrupting integrated metabolic and epigenetic pathways and reversing pathognomonic H3K27me3 reduction. SIGNIFICANCE: The clinical, radiographic, and molecular analyses included in this study demonstrate the efficacy of ONC201 in H3K27M-mutant DMG and support ONC201 as the first monotherapy to improve outcomes in H3K27M-mutant DMG beyond radiation. Mechanistically, ONC201 disrupts integrated metabolic and epigenetic pathways and reverses pathognomonic H3K27me3 reduction. This article is featured in Selected Articles from This Issue, p. 2293.

Analysis of Female Participant Representation in Registered Oncology Clinical Trials in the United States from 2008 to 2020.

BACKGROUND: Female underrepresentation in oncology clinical trials can result in outcome disparities. We evaluated female participant representation in US oncology trials by intervention type, cancer site, and funding. MATERIALS AND METHODS: Data were extracted from the publicly available Aggregate Analysis of ClinicalTrials.gov database. Initially, 270,172 studies were identified. Following the exclusion of trials using Medical Subject Heading terms, manual review, those with incomplete status, non-US location, sex-specific organ cancers, or lacking participant sex data, 1650 trials consisting of 240,776 participants remained. The primary outcome was participation to prevalence ratio (PPR): percent females among trial participants divided by percent females in the disease population per US Surveillance, Epidemiology, and End Results Program data. PPRs of 0.8-1.2 reflect proportional female representation. RESULTS: Females represented 46.9% of participants (95% CI, 45.4-48.4); mean PPR for all trials was 0.912. Females were underrepresented in surgical (PPR 0.74) and other invasive (PPR 0.69) oncology trials. Among cancer sites, females were underrepresented in bladder (odds ratio [OR] 0.48, 95% CI 0.26-0.91, P = .02), head/neck (OR 0.44, 95% CI 0.29-0.68, P < .01), stomach (OR 0.40, 95% CI 0.23-0.70, P < .01), and esophageal (OR 0.40 95% CI 0.22-0.74, P < .01) trials. Hematologic (OR 1.78, 95% CI 1.09-1.82, P < .01) and pancreatic (OR 2.18, 95% CI 1.46-3.26, P < .01) trials had higher odds of proportional female representation. Industry-funded trials had greater odds of proportional female representation (OR 1.41, 95% CI 1.09-1.82, P = .01) than US government and academic-funded trials. CONCLUSIONS: Stakeholders should look to hematologic, pancreatic, and industry-funded cancer trials as exemplars of female participant representation and consider female representation when interpreting trial results.

Receptor tyrosine kinase (RTK) targeting in pediatric high-grade glioma and diffuse midline glioma: Pre-clinical models and precision medicine.

Pediatric high-grade glioma (pHGG), including both diffuse midline glioma (DMG) and non-midline tumors, continues to be one of the deadliest oncologic diagnoses (both henceforth referred to as "pHGG"). Targeted therapy options aimed at key oncogenic receptor tyrosine kinase (RTK) drivers using small-molecule RTK inhibitors has been extensively studied, but the absence of proper in vivo modeling that recapitulate pHGG biology has historically been a research challenge. Thankfully, there have been many recent advances in animal modeling, including Cre-inducible transgenic models, as well as intra-uterine electroporation (IUE) models, which closely recapitulate the salient features of human pHGG tumors. Over 20% of pHGG have been found in sequencing studies to have alterations in platelet derived growth factor-alpha (PDGFRA), making growth factor modeling and inhibition via targeted tyrosine kinases a rich vein of interest. With commonly found alterations in other growth factors, including FGFR, EGFR, VEGFR as well as RET, MET, and ALK, it is necessary to model those receptors, as well. Here we review the recent advances in murine modeling and precision targeting of the most important RTKs in their clinical context. We additionally provide a review of current work in the field with several small molecule RTK inhibitors used in pre-clinical or clinical settings for treatment of pHGG.

Serial H3K27M cell-free tumor DNA (cf-tDNA) tracking predicts ONC201 treatment response and progression in diffuse midline glioma.

BACKGROUND: Diffuse Midline Glioma (DMG) with the H3K27M mutation is a lethal childhood brain cancer, with patients rarely surviving 2 years from diagnosis. METHODS: We conducted a multi-site Phase 1 trial of the imipridone ONC201 for children with H3K27M-mutant glioma (NCT03416530). Patients enrolled on Arm D of the trial (n = 24) underwent serial lumbar puncture for cell-free tumor DNA (cf-tDNA) analysis and patients on all arms at the University of Michigan underwent serial plasma collection. We performed digital droplet polymerase chain reaction (ddPCR) analysis of cf-tDNA samples and compared variant allele fraction (VAF) to radiographic change (maximal 2D tumor area on MRI). RESULTS: Change in H3.3K27M VAF over time ("VAF delta") correlated with prolonged PFS in both CSF and plasma samples. Nonrecurrent patients that had a decrease in CSF VAF displayed a longer progression free survival (P = .0042). Decrease in plasma VAF displayed a similar trend (P = .085). VAF "spikes" (increase of at least 25%) preceded tumor progression in 8/16 cases (50%) in plasma and 5/11 cases (45.4%) in CSF. In individual cases, early reduction in H3K27M VAF predicted long-term clinical response (>1 year) to ONC201, and did not increase in cases of later-defined pseudo-progression. CONCLUSION: Our work demonstrates the feasibility and potential utility of serial cf-tDNA in both plasma and CSF of DMG patients to supplement radiographic monitoring. Patterns of change in H3K27M VAF over time demonstrate clinical utility in terms of predicting progression and sustained response and possible differentiation of pseudo-progression and pseudo-response.

Increased Intraoperative Faculty Entrustment and Resident Entrustability Does Not Compromise Patient Outcomes After General Surgery Procedures.

BACKGROUND: Intraoperative resident autonomy has been compromised secondary to expectations for increased supervision without defined parameters for safe progressive independence, diffusion of training experience, and more to learn with less time. Surgical residents who are insufficiently entrusted during training attain less autonomy, confidence, and even clinical competency, potentially affecting future patient outcomes. OBJECTIVE: To determine if OpTrust, an educational intervention for increasing intraoperative faculty entrustment and resident entrustability, negatively impacts patient outcomes after general surgery procedures. METHODS: Surgical faculty and residents received OpTrust training and instruction to promote intraoperative faculty entrustment and resident entrustability. A post-intervention OpTrust cohort was compared to historical and pre-intervention OpTrust cohorts. Multivariable logistic and negative binomial regression was used to evaluate the impact of the OpTrust intervention and time on patient outcomes. SETTING: Single tertiary academic center. PARTICIPANTS: General surgery faculty and residents. MAIN OUTCOMES AND MEASURES: Thirty-day postoperative outcomes, including mortality, any complication, reoperation, readmission, and length of stay. RESULTS: A total of 8890 surgical procedures were included. After risk adjustment, overall patient outcomes were similar. Multivariable regression estimating the effect of the OpTrust intervention and time revealed similar patient outcomes with no increased risk (P > 0.05) of mortality {odds ratio (OR), 2.23 [95% confidence interval (CI), 0.87-5.6]}, any complication [OR, 0.98 (95% CI, 0.76-1.3)], reoperation [OR, 0.65 (95% CI, 0.42-1.0)], readmission [OR, 0.82 (95% CI, 0.57-1.2)], and length of stay [OR, 0.99 (95% CI, 0.86-1.1)] compared to the historic and pre-intervention OpTrust cohorts. CONCLUSIONS: OpTrust, an educational intervention to increase faculty entrustment and resident entrustability, does not compromise postoperative patient outcomes. Integrating faculty and resident development to further enhance entrustment and entrustability through OpTrust may help facilitate increased resident autonomy within the safety net of surgical training without negatively impacting clinical outcomes.

Assessing patient perception of risk in ocular stem cell therapies.

A wide variety of stem cell-derived therapies are under development for the treatment of retinal degeneration. In order to better understand patient perspectives about these therapies, we assessed risk tolerance using an in-person survey of 178 patients at an academic eye center. Risk of malignancy served as a hypothetical, readily understood, and serious adverse event to be considered in trade for potential visual improvement from a stem cell-derived treatment. The results indicate that patients were willing to trade visual improvement against a risk of malignancy that far exceeds actual risk. Two novel findings were that older patients and those with an intermediate level of visual loss were particularly risk tolerant. The quantitative survey results provide a step toward understanding patient perspectives that will, over the long term, guide the development of ocular stem cell-derived therapies.

Patient Perceptions of SARS-CoV-2 Exposure Risk and Association With Continuity of Ophthalmic Care.

Importance: Patient perceptions regarding the risks of obtaining in-person ophthalmic care during the coronavirus disease 2019 (COVID-19) pandemic may affect adherence to recommended treatment plans and influence visual outcomes. A deeper understanding of patient perspectives will inform strategies to optimize adherence with vision-preserving therapies. Objective: To evaluate perceptions of COVID-19 exposure risk and their association with appointment attendance among patients at high risk of both reversible and irreversible vision loss from lapses in care. Design, Setting, and Participants: This survey study included a nonvalidated telephone survey designed in April and May of 2020 and a retrospective medical record review conducted in parallel with survey administration from May 22 to August 18, 2020. Participants were recruited from 2 tertiary eye care centers (Emory Eye Center in Atlanta, Georgia, and W.K. Kellogg Eye Center in Ann Arbor, Michigan). The study included a random sample of patients with diagnoses of exudative age-related macular degeneration (AMD) or diabetic retinopathy (DR) who received an intravitreal injection between January 6 and March 13, 2020, and were scheduled for a second injection between March 13 and May 6, 2020. Main Outcomes and Measures: Association between perceptions regarding COVID-19 risks and loss to follow-up. Results: Of 1004 eligible patients, 423 (42%) were successfully contacted, and 348 (82%) agreed to participate (participants' mean [SD] age, 75 [12] years; 195 women [56%]; 287 White [82%] patients). Respondents had a mean (SD) of 2.7 (1.1) comorbidities associated with severe COVID-19, and 77 (22%) knew someone with COVID-19. Of all respondents, 163 (47%) were very concerned or moderately concerned about vision loss from missed treatments during the pandemic. Although 208 (60%) believed the COVID-19 virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exposure at the eye clinic was extremely unlikely or unlikely, 49 (14%) believed it was extremely likely or likely. Seventy-eight participants (22%) were lost to follow-up. Concern regarding COVID-19 exposure during clinic visits (odds ratio [OR], 3.9; 95% CI, 1.8-8.4) and diagnosis of DR (vs AMD) (OR, 8.130; 95% CI, 3.367-20.408) were associated with an increase in likelihood of loss to follow-up. Conclusions and Relevance: Among patients at high risk for vision loss from lapses in care, many expressed concerns regarding the effect of the pandemic on their ability to receive timely care. Survey results suggest that fear of SARS-CoV-2 exposure was associated with a roughly 4-fold increase in the odds of patient loss to follow-up. These results support the potential importance of clearly conveying infection-control measures.

Association of intraoperative entrustment with clinical competency amongst general surgery residents.

BACKGROUND: Lack of transparency and meaningful assessment in surgical residency has led to inconsistent intraoperative entrustment and highly variable trainee competence at graduation. The relationship between faculty entrustment and resident entrustability on clinical competency remains unclear. We sought to evaluate the dynamic between entrustment/entrustability and clinical competency in general surgery residency. METHODS: Intraoperative observations were conducted across a 22-month period at an academic tertiary center. Entrustment/entrustability were measured using OpTrust. Clinical competencies were appraised via ACGME Milestones and Objective Structured Assessment of Technical Skill (OSATS) scores. Mixed effects linear regression was used to investigate the relationship among overall ACGME Milestone scores, OSATS domain scores, and overall OpTrust scores. RESULTS: Overall OpTrust scores significantly correlated with overall Milestone scores and multiple OSATS score domains. CONCLUSIONS: OpTrust demonstrated a positive association between ACGME general surgery Milestones and OSATS scores. Overall, OpTrust may help optimize intraoperative faculty entrustment and resident entrustability, facilitating surgical trainee success during residency.

Propagating Humanized BLT Mice for the Study of Human Immunology and Immunotherapy.

The humanized bone marrow-liver-thymus (BLT) mouse model harbors a nearly complete human immune system, therefore providing a powerful tool to study human immunology and immunotherapy. However, its application is greatly limited by the restricted supply of human CD34+ hematopoietic stem cells and fetal thymus tissues that are needed to generate these mice. The restriction is especially significant for the study of human immune systems with special genetic traits, such as certain human leukocyte antigen (HLA) haplotypes or monogene deficiencies. To circumvent this critical limitation, we have developed a method to quickly propagate established BLT mice. Through secondary transfer of bone marrow cells and human thymus implants from BLT mice into NSG (NOD/SCID/IL-2Rγ-/-) recipient mice, we were able to expand one primary BLT mouse into a colony of 4-5 proBLT (propagated BLT) mice in 6-8 weeks. These proBLT mice reconstituted human immune cells, including T cells, at levels comparable to those of their primary BLT donor mouse. They also faithfully inherited the human immune cell genetic traits from their donor BLT mouse, such as the HLA-A2 haplotype that is of special interest for studying HLA-A2-restricted human T cell immunotherapies. Moreover, an EGFP reporter gene engineered into the human immune system was stably passed from BLT to proBLT mice, making proBLT mice suitable for studying human immune cell gene therapy. This method provides an opportunity to overcome a critical hurdle to utilizing the BLT humanized mouse model and enables its more widespread use as a valuable preclinical research tool.

Genetic engineering of hematopoietic stem cells to generate invariant natural killer T cells.

Invariant natural killer T (iNKT) cells comprise a small population of αß T lymphocytes. They bridge the innate and adaptive immune systems and mediate strong and rapid responses to many diseases, including cancer, infections, allergies, and autoimmunity. However, the study of iNKT cell biology and the therapeutic applications of these cells are greatly limited by their small numbers in vivo (∼0.01-1% in mouse and human blood). Here, we report a new method to generate large numbers of iNKT cells in mice through T-cell receptor (TCR) gene engineering of hematopoietic stem cells (HSCs). We showed that iNKT TCR-engineered HSCs could generate a clonal population of iNKT cells. These HSC-engineered iNKT cells displayed the typical iNKT cell phenotype and functionality. They followed a two-stage developmental path, first in thymus and then in the periphery, resembling that of endogenous iNKT cells. When tested in a mouse melanoma lung metastasis model, the HSC-engineered iNKT cells effectively protected mice from tumor metastasis. This method provides a powerful and high-throughput tool to investigate the in vivo development and functionality of clonal iNKT cells in mice. More importantly, this method takes advantage of the self-renewal and longevity of HSCs to generate a long-term supply of engineered iNKT cells, thus opening up a new avenue for iNKT cell-based immunotherapy.