A non-human primate model of acute liver failure suitable for testing liver support systems

Acute hepatic failure is associated with high morbidity and mortality for which the only definitive therapy is liver transplantation. Some fraction of those who undergo emergency transplantation have been shown to recover native liver function when transplanted with an auxiliary hepatic graft that leaves part of the native liver intact. Thus, transplantation could have been averted with the development and use of some form of hepatic support. The costs of developing and testing liver support systems could be dramatically reduced by the availability of a reliable large animal model of hepatic failure with a large therapeutic window that allows the assessment of efficacy and timing of intervention. Non-lethal forms of hepatic injury were examined in combination with liver-directed radiation in non-human primates (NHPs) to develop a model of acute hepatic failure that mimics the human condition. Porcine hepatocyte transplantation was then tested as a potential therapy for acute hepatic failure. After liver-directed radiation therapy, delivery of a non-lethal hepatic ischemia-reperfusion injury reliably and rapidly generated liver failure providing conditions that can enable pre-clinical testing of liver support or replacement therapies. Unfortunately, in preliminary studies, low hepatocyte engraftment and over-immune suppression interfered with the ability to assess the efficacy of transplanted porcine hepatocytes in the model. A model of acute liver failure in NHPs was created that recapitulates the pathophysiology and pathology of the clinical condition, does so with reasonably predictable kinetics, and results in 100% mortality. The model allowed preliminary testing of xenogeneic hepatocyte transplantation as a potential therapy.

Phase II study of durvalumab following neoadjuvant chemoRT in operable rectal cancer: NSABP FR-2

99

Background: Although immunotherapy shows no benefit in microsatellite stable (MSS) colorectal cancer, preclinical models suggest that radiotherapy (RT) can enhance neoantigen presentation, modulate the microenvironment, and improve the likelihood of anti-tumor activity with checkpoint inhibitor use. Using a “window-of-opportunity” study design, this prospective phase II trial will determine the safety and activity of this approach with the anti-PD-L1 agent durvalumab (MEDI4736). Methods: Stage II/III patients (pts) with MSS rectal cancer undergoing standard NCCN guideline-compliant neoadjuvant chemoradiotherapy (CRT) followed by definitive surgery were eligible. Treatment included durvalumab (750mg IV infusion once every 2 wks) for 4 total doses beginning within 3-7 days after CRT completion followed by surgery within 8-12 wks of the final CRT dose. Primary end point (EP): Improvement in modified neoadjuvant rectal cancer (mNAR) score (goal 10.6) compared to historical controls (15.6) targeting a 20% DFS RR reduction and 3-4% absolute OS improvement. Secondary EPs: toxicity, pCR, cCR, therapy completion, negative surgical margins, sphincter preservation, and exploratory assessments of tumor-infiltrating lymphocytes, tumor Immunoscore, circulating immunologic profiles, and molecular predictors of response. We test H0: mNAR ≥15.6 vs HA: mNAR <15.6 at alpha 0.10 one-sided with statistical significance defined as p<0.1. Results: From May 2018 to October 2020, 45 pts were enrolled with 40 pts evaluable for mNAR. Mean mNAR was 12.03 (80% CI: 9.29-14.97) (p=0.06 one-sided). pCR=22.2%; cCR=31.1%; R0 resection=81.0%, and sphincter preservation=71.4%. Side effects were consistent with both CRT and durvalumab safety profile. Most common grade 3 AEs included diarrhea, lymphopenia, and back pain. There was one grade 4 AE (elevated amylase/lipase) and no grade 5 AEs. Remaining secondary and correlative immunologic end points are still being assessed. Conclusions: Durvalumab immediately following CRT prior to surgery for definitive management of rectal cancer was safe and without unexpected short-term toxicities. The primary end point of mean mNAR score was significantly less than our historical control, warranting further investigation. Correlative analyses for immunologic markers of response including PD-(L)1 expression and Immunoscore are ongoing. NCT 03102047. Support: AstraZeneca-Medimmune, NSABP Foundation. Clinical trial information: NCT03102047.

Field-induced vortex-like textures as a probe of the critical line in reentrant spin glasses

We study the evolution of the low-temperature field-induced magnetic defects observed under an applied magnetic field in a series of frustrated amorphous ferromagnets (Fe\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{1-x}$$\end{document}1-xMn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{x}$$\end{document}x)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{75}$$\end{document}75P\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{16}$$\end{document}16B\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{3}$$\end{document}3Al\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{3}$$\end{document}3 (“a-Fe\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{1-x}$$\end{document}1-xMn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{x}$$\end{document}x”). Combining small-angle neutron scattering and Monte Carlo simulations, we show that the morphology of these defects resemble that of quasi-bidimensional spin vortices. They are observed in the so-called “reentrant” spin-glass (RSG) phase, up to the critical concentration \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$x_{\mathrm{C}} \approx 0.36$$\end{document}xC≈0.36 which separates the RSG and “true” spin glass (SG) within the low temperature part of the magnetic phase diagram of a-Fe_1−xMn_x. These textures systematically decrease in size with increasing magnetic field or decreasing the average exchange interaction, and they finally disappear in the SG sample (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$x = 0.41$$\end{document}x=0.41), being replaced by field-induced correlations over finite length scales. We argue that the study of these nanoscopic defects could be used to probe the critical line between the RSG and SG phases.

NSABP FR-2: Phase II study of durvalumab following neoadjuvant chemoRT in stage II-IV rectal cancer

TPS264

Background: Clinical improvements for locally advanced rectal cancer have been relatively static over the past few decades. While immunotherapy shows no benefit in microsatellite stable (MSS) colorectal cancer, preclinical models suggest that radiotherapy (RT) can enhance neoantigen presentation, modulate the microenvironment, and improve the likelihood of anti-tumor activity with checkpoint inhibitor use. Using a “window-of-opportunity” study design, this prospective phase II trial will determine the safety and activity of this approach with the anti-PD-L1 agent durvalumab (MEDI4736). Methods: This multi-center phase II trial is currently enrolling patients (pts) with rectal cancer who are undergoing standard NCCN guideline-compliant neoadjuvant chemoradiotherapy (CRT). Eligibility includes pts with MSS stage II-IV rectal cancer with adequate organ function and pre-treatment diagnostic tumor available for profiling with intent to proceed to surgical resection after CRT. Stage IV disease must be limited such that the primary pelvic tumor requires definitive management. Standard ineligibility criteria include active infections, systemic steroid use, or other conditions making immunotherapy use unsafe. Treatment includes durvalumab (750mg IV infusion once every 2 wks) for 4 total doses beginning within 3-7 days after CRT completion. Surgery must be within 8-12 wks of the final CRT dose. Primary endpoint is a demonstrated improvement in Neoadjuvant Rectal Cancer (NAR) score compared to historical controls targeting a 20% relative risk reduction in DFS and 3-4% absolute OS improvement. Secondary endpoints include OS, DFS, toxicity, pCR, cCR, therapy completion, negative surgical margins, sphincter preservation, off-target “abscopal” effects for the subset of stage IV pts, and exploratory assessments of tumor infiltrating lymphocytes, tumor Immunoscore, circulating immunologic profiles, and molecular predictors of response. A safety run-in phase has completed as a precedent to full enrollment. Enrollment now continues to 47 total pts to achieve 41 surgically evaluable pts. Support: AstraZeneca-Medimmune, NSABP Foundation. Clinical trial information: NCT03102047.

Phase II study of durvalumab following neoadjuvant chemoRT in stage II-IV rectal cancer: NSABP FR-2

TPS3620

Background: Locally advanced rectal cancer remains a clinical challenge with few improvements noted over the past few decades. Although immunotherapy has no current clinical role in microsatellite stable (MSS) colorectal cancer, preclinical models suggest that radiotherapy (RT) can enhance neoantigen presentation, modulate the microenvironment, and improve the likelihood of anti-tumor activity with checkpoint inhibitor use. This prospective phase II trial will test that hypothesis in addition to confirming the safety of this approach using a “window-of-opportunity” study design with the anti-PD-L1 agent durvalumab (MEDI4736). Methods: This multi-center phase II trial is currently enrolling patients (pts) with rectal cancer who are undergoing standard NCCN guideline-compliant neoadjuvant chemoradiotherapy (CRT). Eligibility includes pts with MSS stage II-IV rectal cancer with adequate organ function and pre-treatment diagnostic tumor available for profiling who are undergoing CRT with intent to proceed to surgical resection. Stage IV disease must be limited such that the primary pelvic tumor requires definitive management. Standard ineligibility criteria include active infections, systemic steroid use, or other conditions making immunotherapy use unsafe. Treatment includes durvalumab (750mg IV infusion once every 2 wks) for 4 total doses beginning within 3-7 days after CRT completion. Surgery must be within 8-12 wks of the final CRT dose. Primary endpoint is a demonstrated improvement in Neoadjuvant Rectal Cancer (NAR) score compared to historical controls targeting a 20% relative risk reduction in DFS and 3-4% absolute OS improvement. Secondary endpoints include OS, DFS, toxicity, pCR, cCR, therapy completion, negative surgical margins, sphincter preservation, off-target “abscopal” effects for the subset of stage IV pts, and exploratory assessments of tumor infiltrating lymphocytes, circulating immunologic profiles, and molecular predictors of response. A safety run-in phase has completed as a precedent to full enrollment. Enrollment now continues to 47 total pts to achieve 41 surgically evaluable pts. Support: AstraZeneca-Medimmune, NSABP Foundation. Clinical trial information: NCT03102047.

NSABP FR-2: Phase II study of durvalumab following neoadjuvant chemoRT in stage II-IV rectal cancer

TPS727

Background: Locally advanced rectal cancer remains a clinical challenge with few improvements noted over the past few decades. Although immunotherapy has no current clinical role in microsatellite stable (MSS) colorectal cancer, preclinical models suggest that radiotherapy (RT) can enhance neoantigen presentation, modulate the microenvironment, and improve the likelihood of anti-tumor activity with checkpoint inhibitor use. This prospective phase II trial will test that hypothesis in addition to confirming safety of this approach using a “window-of-opportunity” study design with the anti-PD-L1 agent durvalumab (MEDI4736). Methods: This multi-center phase II trial is currently enrolling patients (pts) with rectal cancer who are undergoing standard NCCN guideline-compliant neoadjuvant chemoradiotherapy (CRT). Eligibility includes pts with MSS stage II-IV rectal cancer with adequate organ function and pre-treatment diagnostic tumor available for profiling who are undergoing CRT with intentions to proceed to surgical resection. Stage IV disease must be limited such that the primary pelvic tumor requires definitive management. Standard ineligibility criteria include active infections, systemic steroid use, or other conditions making immunotherapy use unsafe. Treatment includes durvalumab (750mg IV infusion once every 2 wks) for 4 total doses beginning within 3-7 days after CRT completion. Surgery must be within 8-12 wks of the final CRT dose. Primary endpoint is a demonstrated improvement in Neoadjuvant Rectal Cancer (NAR) score compared to historical controls targeting a 20% relative risk reduction in DFS and 3-4% absolute OS improvement. Secondary endpoints include OS, DFS, toxicity, pCR, cCR, therapy completion, negative surgical margins, sphincter preservation, off-target “abscopal” effects for the subset of stage IV pts, and exploratory assessments of tumor infiltrating lymphocytes, circulating immunologic profiles, and molecular predictors of response. A safety run-in phase has completed as a precedent to full enrollment. Enrollment now continues to 47 total pts to achieve 41 surgically evaluable pts. NCT03102047. Support: AstraZeneca-Medimmune, NSABP Foundation Clinical trial information: NCT03102047.

A 58-Year-Old Woman with Left-Sided Weakness and a History of a Pediatric Brain Tumor: A Case Report

Background

An uncommon but well-established complication of cranial irradiation is secondary neoplasm. This case presentation documents a radiation-induced malignant glioma 55 years after being diagnosed with “cerebral sarcoma,” now defined as atypical meningioma. This not only represents the longest reported latency period for a patient initially receiving over 30 Gy, but also provides a valuable historical perspective of neuro-oncology.

Clinical Presentation

A 58-year-old female presenting with progressive left-sided upper and lower extremity weakness with a past medical history significant for “cerebral sarcoma” was diagnosed with glioblastoma multiforme. This patient had previously been treated with resection and adjuvant radiation therapy via a 280-kVP orthovoltage machine and received 3,390 rad to the posterior three-quarters of the skull for “cerebral sarcoma.”

Conclusion

A comprehensive investigation of the past medical history helped uncover a mysterious pediatric diagnosis, helped drive the management 5 decades later, and serves as a reminder that seemingly safe interventions may still cause harm.

An Information-theoretical Model for Breast Cancer Detection

Objectives: Formal diagnostic modeling is an important line of modern biological and medical research. The construction of a formal diagnostic model consists of two stages: first, the estimation of correlation between model parameters and the disease under consideration; and second, the construction of a diagnostic decision rule using these correlation estimates. A serious drawback of current diagnostic models is the absence of a unified mathematical methodological approach to implementing these two stages. The absence of aunified approach makesthe theoretical/biomedical substantiation of diagnostic rules difficult and reduces the efficacyofactual diagnostic model application. Methods: The present study constructs a formal model for breast cancer detection. The diagnostic model is based on information theory. Normalized mutual information is chosen as the measure of relevance between parameters and the patterns studied. The “nearest neighbor” rule is utilized for diagnosis, while the distance between elements is the weighted Hamming distance. The model concomitantly employs cellular fluorescence polarization as the quantitative input parameter and cell receptor expression as qualitative parameters.

Results: Twenty-four healthy individuals and 34 patients (not including the subjects analyzed for the model construction) were tested by the model. Twenty-three healthy subjects and 34 patients were correctly diagnosed.

Conclusions: The proposed diagnostic model is an open one,i.e.it can accommodate new additional parameters, which may increase its effectiveness.

Host conditioning and rejection monitoring in hepatocyte transplantation in humans

BACKGROUND & AIMS

Hepatocyte transplantation partially corrects genetic disorders and has been associated anecdotally with reversal of acute liver failure. Monitoring for graft function and rejection has been difficult, and has contributed to limited graft survival. Here we aimed to use preparative liver-directed radiation therapy, and continuous monitoring for possible rejection in an attempt to overcome these limitations.

METHODS

Preparative hepatic irradiation was examined in non-human primates as a strategy to improve engraftment of donor hepatocytes, and was then applied in human subjects. T cell immune monitoring was also examined in human subjects to assess adequacy of immunosuppression.

RESULTS

Porcine hepatocyte transplants engrafted and expanded to comprise up to 15% of irradiated segments in immunosuppressed monkeys preconditioned with 10Gy liver-directed irradiation. Two patients with urea cycle deficiencies had early graft loss following hepatocyte transplantation; retrospective immune monitoring suggested the need for additional immunosuppression. Preparative radiation, anti-lymphocyte induction, and frequent immune monitoring were instituted for hepatocyte transplantation in a 27year old female with classical phenylketonuria. Post-transplant liver biopsies demonstrated multiple small clusters of transplanted cells, multiple mitoses, and Ki67+ hepatocytes. Mean peripheral blood phenylalanine (PHE) level fell from pre-transplant levels of 1343±48μM (normal 30-119μM) to 854±25μM (treatment goal ≤360μM) after transplant (36% decrease; p<0.0001), despite transplantation of only half the target number of donor hepatocytes. PHE levels remained below 900μM during supervised follow-up, but graft loss occurred after follow-up became inconsistent.

CONCLUSIONS

Radiation preconditioning and serial rejection risk assessment may produce better engraftment and long-term survival of transplanted hepatocytes. Hepatocyte xenografts engraft for a period of months in non-human primates and may provide effective therapy for patients with acute liver failure.

LAY SUMMARY

Hepatocyte transplantation can potentially be used to treat genetic liver disorders but its application in clinical practice has been impeded by inefficient hepatocyte engraftment and the inability to monitor rejection of transplanted liver cells. In this study, we first show in non-human primates that pretreatment of the host liver with radiation improves the engraftment of transplanted liver cells. We then used this knowledge in a series of clinical hepatocyte transplants in patients with genetic liver disorders to show that radiation pretreatment and rejection risk monitoring are safe and, if optimized, could improve engraftment and long-term survival of transplanted hepatocytes in patients.