Recommendations for the Management of Initial and Refractory Pediatric Status Dystonicus

Status dystonicus is the most severe form of dystonia with life-threatening complications if not treated promptly. We present consensus recommendations for the initial management of acutely worsening dystonia (including pre-status dystonicus and status dystonicus), as well as refractory status dystonicus in children. This guideline provides a stepwise approach to assessment, triage, interdisciplinary treatment, and monitoring of status dystonicus. The clinical pathways aim to: (1) facilitate timely recognition/triage of worsening dystonia, (2) standardize supportive and dystonia-directed therapies, (3) provide structure for interdisciplinary cooperation, (4) integrate advances in genomics and neuromodulation, (5) enable multicenter quality improvement and research, and (6) improve outcomes. © 2024 International Parkinson and Movement Disorder Society.

Evaluation of a Deep-Learning Auto-Segmentation Model of Cardiac Substructures

PURPOSE/OBJECTIVE(S)

Increasing evidence has suggested that limiting dose not only to the whole heart but also to cardiac substructures can potentially reduce cardiac toxicities. Manual contouring of cardiac substructure can be challenging and time-consuming. To address this concern, we developed a deep learning (DL) model, trained on convolutional neural network algorithms in large external datasets, for auto-segmentation of cardiac substructures. This study aimed to evaluate the quality of the cardiac substructure contours generated by the DL algorithm.

MATERIALS/METHODS

We identified 28 patients with esophagus or gastroesophageal junction cancer from a single institution who received radiation to the esophagus between January 2017 and December 2022. For each case, the DL-generated cardiac substructures (4 heart chambers - left/right atrium [L/RA] and L/R ventricle [L/RV], 4 coronary arteries - L common [LCA], L anterior descending [LAD], L circumflex [LCx], and R common [RCA], and great vessels - ascending aorta [AA], pulmonary artery [PA], and superior vena cava [SVC]) were modified by two radiation oncologists (RO) using the contouring atlas developed by Duane et al. Spatial overlapping of the contours were then assessed using the Dice similarity coefficient (DSC), 95th percentile Hausdorff distance (HD-95), and normalized surface dice at 2 mm tolerance (NSD-2).

RESULTS

The mean values of DSC, HD-95, and NSD-2 are shown in Table 1. Overall, the mean DSC, HD-95, and NSD-2 for the heart chambers ranged from 0.82 to 0.92, 0.40 cm to 1.52 cm, and 0.68 to 0.85, respectively. Ranges of the mean DSC, HD-95, and NSD-2 for the coronary vessels were 0.41 to 0.74, 0.18 cm to 0.98 cm, and 0.66 to 0.77, respectively. Lastly, comparison of the great vessel contours yielded the following ranges for mean DSC, HD-95, and NSD-2 respectively: 0.72 to 0.92, 0.30 cm to 1.64 cm, and 0.65 to 0.83.

CONCLUSION

Our study demonstrates that auto-segmentation of cardiac substructures by DL-powered models can be comparable to manual contours for certain cardiac substructures, namely the four heart chambers and great vessels. Further improvement of the DL on contouring of coronary vessels would be needed prior to the autosegmentation model being widely adopted.

Patient and Caregivers Opinions on Receiving Radiology Results before Oncologist Appointments

PURPOSE/OBJECTIVE(S)

With the passing of the Cures Act, patients now have immediate access to radiology reports and can review the results before discussing the findings with a physician. In Oncology, the results of these imaging reports can be especially sensitive as the results can lead to difficult discussions about patient prognosis, or the need for invasive medical, surgical, or radiation therapies. It is unclear whether immediate access may increase anxiety, stress, and confusion before discussions with an oncologist. In this study, we hypothesized that in the oncology setting, immediate access to imaging reports before meeting with their oncologist would be associated with worsened patient anxiety.

MATERIALS/METHODS

Patients and their caregivers were invited to complete an investigator-developed anonymous multiple-choice survey prior to a scheduled follow-up appointment with their radiation oncologist. Survey questions assessed preferences for reviewing the radiology report prior to their oncology visit, their reported level of anxiety before undergoing diagnostic imaging, after directly receiving their results, and after they have the discussion of their results with the oncologist. Additional metrics collected included patient demographics, the time interval between discussing the results with an oncologist, preference for reviewing the images or just the radiology report, satisfaction with having immediate access to the report, and if they would prefer being blinded from the results until after discussing with their oncologist. Survey items were scored descriptively through summary statistics.

RESULTS

In this interim report of 54 individuals surveyed over a two-week period (89% were patients, 11% were caregivers/family members), a combined 33% reported a high level of anxiety before undergoing their scan. Levels of high anxiety decreased to 20% for those who received their report prior to reviewing with their oncologist and further lowered to 13% after reviewing the report and images with their oncologist. 57% of responders reported discussing the results with an oncologist within 2 days of receiving results. 46% preferred reviewing only radiology reports and not the images, 35% favored reviewing both imaging and the report together and 19% had no preference. Only 18.5% of responders preferred viewing the reports before discussing them with their oncologist and only 20% felt it was beneficial having early access to them.

CONCLUSION

Anxiety associated with oncology-related imaging improved after immediate access to the report and after discussions with oncologists. A small proportion of patients preferred having early access to imaging reports and most patients preferred reviewing only the report, not the images. Strategies including shortened intervals between immediate access and discussions with oncologists may minimize anxiety associated with imaging as most patients preferred first discussing the results with their oncologist.

Incidence of Major Depression, Suicidal Ideation, and Mental Health Treatment Amongst Cancer Survivors

PURPOSE/OBJECTIVE(S)

Receiving a cancer diagnosis and undergoing subsequent treatments can result in a significant psychological burden for cancer patients. However, there is conflicting literature on the incidence of major depression in cancer patients compared to patients without cancer. The purpose of this study was to investigate and further clarify the incidence of major depression, associated treatments, and suicidal ideation in cancer survivors compared to a non-cancer cohort.

MATERIALS/METHODS

This is a retrospective, population-based study using survey responses from the National Survey on Drug Use and Health collected from January 2015 to December 2019. Survey data sets were queried for all respondents aged 18 years or older who provided a cancer history. Patients with a reported history of cancer ("cancer survivors") were further stratified by whether they reported a "recent" cancer diagnosis within the past 12 months. Survey responses were then evaluated for recent diagnoses of and treatments for major depressive disorder and suicidal ideation. Rates were compared between cancer survivors and participants without cancer using the Pearson χ2 test and multivariable logistic regression models, respectively.

RESULTS

Among the 212,411 survey respondents identified, 7,635 (3.6%) reported a cancer history, with 1,486 (0.7%) reporting a recent cancer history. The incidence of major depression was not different between cancer survivors and participants without cancer (9.3% vs. 9.2%; p = 0.762), though the incidence was slightly higher amongst recent cancer survivors (10.0% vs. 9.2%; p = 0.259). Among patients diagnosed with major depression, cancer survivors were significantly more likely to receive treatment for depression (78.6% vs. 60.3%, p<0.001), with 72.6% discussing depressive symptoms with a medical professional and 64.3% receiving prescription medication. Suicidal ideation was significantly lower among cancer survivors (5.1% vs. 6.2%, p<0.001) including recent survivors (5.0% vs. 6.2%, p<0.001). Suicidal ideation was higher in patients with underlying major depression in both cancer survivors and participants without cancer (30.6% vs. 35.6%, p = 0.015). On logistic regression, respondents with underlying depression receiving treatment were more likely to have suicidal ideation (OR: 1.49; p<0.001) while having a cancer diagnosis did not correlate with suicidal ideation (OR: 0.87; p = 0.869).

CONCLUSION

There was no significant overall difference in the incidences of major depression between cancer survivors and patients without cancer. However, one consideration is the under-diagnosis depression among cancer survivors. Symptoms of depression may be overlooked and mistakenly attributed to appropriate grief from a cancer diagnosis. Among patients diagnosed with major depression, cancer survivors were more likely to receive treatment for depression. These results highlight the importance of early depression assessment and treatment for cancer survivors.

Dosimetric Evaluation of Cardiac Substructures in Irradiation of Esophagus

PURPOSE/OBJECTIVE(S)

Due to the anatomic proximity of the heart, cardiac toxicity is a major concern in radiation treatment (RT) of esophageal cancer. Historically, the entire heart is considered an organ at risk. However, more recent studies have demonstrated that dose to cardiac substructures may better predict cardiac toxicities. We retrospectively reviewed patients (pts) who had RT to the distal esophagus and evaluated the dose-volume constraints (DVCs) of the cardiac substructures and the whole heart. We hypothesized that the majority of the treatment plans would not meet the DVCs to cardiac substructures noted in the current literature, albeit meeting commonly accepted whole heart DVCs.

MATERIALS/METHODS

We identified 27 pts with esophagus or gastroesophageal junction cancer who received RT to the esophagus between January 2017 and December 2022. For each case, the cardiac substructures (4 heart chambers - left/right atrium [L/RA] and left/right ventricle [L/RV], 4 coronary arteries - left common [LCA], left anterior descending [LAD], left circumflex [LCx], and right common [RCA], and great vessels - ascending and descending aorta [A/DA], pulmonary artery [PA], and superior vena cava [SVC]) were contoured based on the contouring atlas developed by Duane et al. DVCs based on existing literature for the whole heart and each cardiac substructure were reviewed and retrospectively analyzed for each treatment plan (Table 1).

RESULTS

Eighteen (66.7%) pts received 50 Gy/25 fractions, and nine (33.3%) pts received 50.4 Gy/28 fractions. The dose-volume constraints for the whole heart and each cardiac substructure are shown in Table 1. When considering the heart as a whole organ, all the treatment plans met the V45 and V40 objectives, with a mean V45 of 7.1% and V40 of 10.8%. All the cases also met the constraints for RV and PA. However, none of the cases met the DVCs for RA or LV. Only 6 (22.2%) of cases met the constraint for LCx or AA.

CONCLUSION

We found that despite all the treatment plans meeting the whole heart V45 and V40 constraints, none of the cases met the dose constraints to all cardiac substructures. This suggests that dosimetric evaluation of the whole heart alone may not be sufficient in minimizing cardiac toxicities from RT, and thus further supports the importance of defining the cardiac substructures. Future studies will be needed to standardize the dose constraints to these substructures to ensure patient safety.

Synergistic Effect of TVEC and Radiotherapy in the Treatment of Advanced Melanoma

PURPOSE/OBJECTIVE(S)

Talimogene laherparepvec (TVEC) is a genetically modified herpes simplex virus (HSV-1) that has been approved by the US Food and Drug Administration (FDA) for intralesional treatment of melanoma. Recent reports have suggested that radiation treatment (RT) given in conjunction with TVEC, may provide synergistic immune enhancement at the site, and possibly systemically. However, the studies on combining RT with TVEC remain limited. Our study compares melanoma patients (pts) who received TVEC and RT in the same region of the body with pts whose RT field did not include the site of TVEC injection. We hypothesized that RT and TVEC to the same site would induce a more robust local tumor response, and possibly a systemic response, with improvement in clinical outcomes over those pts who had treatments in different regions.

MATERIALS/METHODS

This was a retrospective review of 20 melanoma pts from a single cancer center who were treated with TVEC and RT between January 2015 and September 2022. Overall survival (OS), progression-free survival (PFS), time to distant metastasis (DM), and time to locoregional recurrence (LRR) were compared using Kaplan-Meier analysis and the corresponding log-rank test. Skin toxicity was also tabulated.

RESULTS

Fourteen pts (stage III [71.4%]; stage IV [28.6%]) received TVEC and RT in the same region (left leg [5], right leg [5], back [1], left arm [1], and right arm [1], and scalp [1]), and six (stage III [66.7%]; stage IV [33.3%]) received treatments in separate regions. The overall median follow-up was 10.5 months (mos) (range 1.0 - 58.7 mos). The OS of pts who had TVEC and RT in the same region was 19.0 mos (95% confidence interval [CI], 4.1 - not reached [NR] mos), compared to 18.5 mos for those receiving RT in a different region (95% CI, 1.0 - NR mos) (p = 0.366). PFS with TVEC and RT in the same and different regions were 6.4 mos (95% CI, 2.4 - NR mos) and 2.8 mos (95% CI, 0.7 - 4.4 mos) respectively (p = 0.005). DM was 13.8 mos (95% CI, 4.6 - NR mos) with TVEC and RT in the same field and 2.8 mos (95% CI, 0.7 - 4.4 mos) in different fields (p = 0.001). Lastly, LRR of pts who had TVEC and RT in the same region was 26.0 mos (95% CI, 6.4 - 26.0 mos) compared to 4.4 mos in different regions (95% CI, 0.7 - NR mos) (p = 0.115). No grade 3 or higher skin toxicities were documented among pts who had TVEC and RT in the same region.

CONCLUSION

Comparing pts who had TVEC and RT to different regions of the body, there was an association with improvements in PFS and DM when both modalities were delivered to the same region of the body. However, we did not find a significant difference in locoregional recurrence or OS. Given some promise with the combined approach and potential immune enhancement from RT, larger trials are needed to better understand the potential positive signal from our study.

Plasma Neurofilament Light Chain Is Elevated in Adaptor Protein Complex 4-Related Hereditary Spastic Paraplegia

BACKGROUND

Adaptor protein complex 4-associated hereditary spastic paraplegia (AP-4-HSP) is caused by pathogenic biallelic variants in AP4B1, AP4M1, AP4E1, and AP4S1.

OBJECTIVE

The aim was to explore blood markers of neuroaxonal damage in AP-4-HSP.

METHODS

Plasma neurofilament light chain (pNfL) and glial fibrillary acidic protein (GFAP) levels were measured in samples from patients and age- and sex-matched controls (NfL: n = 46 vs. n = 46; GFAP: n = 14 vs. n = 21) using single-molecule array assays. Patients' phenotypes were systematically assessed using the AP-4-HSP natural history study questionnaires, the Spastic Paraplegia Rating Scale, and the SPATAX disability score.

RESULTS

pNfL levels increased in AP-4-HSP patients, allowing differentiation from controls (Mann-Whitney U test: P = 3.0e-10; area under the curve = 0.87 with a 95% confidence interval of 0.80-0.94). Phenotypic cluster analyses revealed a subgroup of individuals with severe generalized-onset seizures and developmental stagnation, who showed differentially higher pNfL levels (Mann-Whitney U test between two identified clusters: P = 2.5e-6). Plasma GFAP levels were unchanged in patients with AP-4-HSP.

CONCLUSIONS

pNfL is a potential disease marker in AP-4-HSP and can help differentiate between phenotypic subgroups. © 2023 International Parkinson and Movement Disorder Society.

Impacts of fast production of afucosylated antibodies and Fc mutants in ExpiCHO-S™ for enhancing FcγRIIIa binding and NK cell activation

This study has employed mammalian transient expression systems to generate afucosylated antibodies and antibody Fc mutants for rapid candidate screening in discovery and early development. While chemical treatment with the fucose analogue 2-fluoro-peracetyl-fucose during transient expression only partially produced antibodies with afucosylated N-glycans, the genetic inactivation of the FUT8 gene in ExpiCHO-S™ by CRISPR/Cas9 enabled the transient production of fully afucosylated antibodies. Human IgG₁ and murine IgG_2a generated by the ExpiCHOfut8KO cell line possessed a 8-to-11-fold enhanced FcγRIIIa binding activity in comparison with those produced by ExpiCHO-S™. The Fc mutant S239D/S298A/I332E produced by ExpiCHO-S™ had an approximate 2-fold higher FcγRIIIa affinity than that of the afucosylated wildtype molecule, although it displayed significantly lower thermal-stability. When the Fc mutant was produced in the ExpiCHOfut8KO cell line, the resulting afucosylated Fc mutant antibody had an additional approximate 6-fold increase in FcγRIIIa binding affinity. This synergistic effect between afucosylation and the Fc mutations was further verified by a natural killer (NK) cell activation assay. Together, these results have not only established an efficient large-scale transient CHO system for rapid production of afucosylated antibodies, but also confirmed a cooperative impact between afucosylation and Fc mutations on FcγRIIIa binding and NK cell activation.

Discovery and multi-parametric optimization of a high-affinity antibody against Interleukin-25 with neutralizing activity in a mouse model of skin inflammation

Background

Interleukin (IL)25 has been implicated in tissue homeostasis at barrier surfaces and the initiation of type two inflammatory signaling in response to infection and cell injury across multiple organs. We sought to discover and engineer a high affinity neutralizing antibody and evaluate the antibody functional activity in vitro and in vivo.

Methods

In this study, we generated a novel anti-IL25 antibody (22C7) and investigated the antibody’s therapeutic potential for targeting IL25 in inflammation.

Results

A novel anti-IL25 antibody (22C7) was generated with equivalent in vitro affinity and potency against the human and mouse orthologs of the cytokine. This translated into in vivo potency in an IL25-induced air pouch model where 22C7 inhibited the recruitment of monocytes, macrophages, neutrophils and eosinophils. Furthermore, 22C7 significantly reduced ear swelling, acanthosis and disease severity in the Aldara mouse model of psoriasiform skin inflammation. Given the therapeutic potential of IL25 targeting in inflammatory conditions, 22C7 was further engineered to generate a highly developable, fully human antibody while maintaining the affinity and potency of the parental molecule.

Conclusions

The generation of 22C7, an anti-IL25 antibody with efficacy in a preclinical model of skin inflammation, raises the therapeutic potential for 22C7 use in the spectrum of IL25-mediated diseases.

780 Are E-Scooters Safe for Widespread Public Use? A Case Series Examining Severe Facial Injuries Secondary to E-Scooter Accidents

E-scooter use is becoming commonplace across the UK as an increasing number of towns and cities launch trials with pay-as-you-go e-scooter companies. In addition, e-scooters are cheap method of transport, easily available for an individual to purchase online, without restriction. We present two cases of patients having suffered complex facial injuries secondary to e-scooter accidents.

The first is a 38-year-old male, who was thrown from an e-scooter and had associated loss of consciousness. CT facial bones demonstrated extensive fractures to the bilateral maxillary and frontal sinuses, nasal bones, bilateral orbital floors, and mandible. The Le Fort II and mandibular fractures were fixed in two procedures. The patient has ongoing neuropathic pain around the right mandibular condyle and is receiving input from orthognathic specialists.

The second patient is a 60-year-old male, who collided with the rear of a car and was thrown forward, hitting his face on the tarmac. CT facial bones showed a Le Fort II fracture pattern and a fractured left inferior orbital rim, with extensive surgical emphysema of the face. He underwent plating of the bilateral Le Fort II fractures and application of intermaxillary fixation wires.

With little to no enforcement of personal protective equipment use and safety advice whilst utilising e-scooter services, the number of people suffering serious injuries from using such equipment is set to skyrocket. Increased awareness and education around the danger of e-scooters needs to be addressed and should be prioritised by local authorities and public health services.

Lipid nanoparticle formulations for optimal RNA-based topical delivery to murine airways

INTRODUCTION

Lipid nanoparticles (LNP) have been successfully used as a platform technology for delivering nucleic acids to the liver. To broaden the application of LNPs in targeting non-hepatic tissues, we developed LNP-based RNA therapies (siRNA or mRNA) for the respiratory tract. Such optimized LNP systems could offer an early treatment strategy for viral respiratory tract infections such as COVID-19.

METHODS

We generated a small library of six LNP formulations with varying helper lipid compositions and characterized their hydrodynamic diameter, size distribution and cargo entrapment properties. Next, we screened these LNP formulations for particle uptake and evaluated their potential for transfecting mRNA encoding green fluorescence protein (GFP) or SARS-CoV2 nucleocapsid-GFP fusion reporter gene in a human airway epithelial cell line in vitro. Following LNP-siGFP delivery, GFP protein knockdown efficiency was assessed by flow cytometry to determine %GFP+ cells and median fluorescence intensity (MFI) for GFP. Finally, lead LNP candidates were validated in Friend leukemia virus B (FVB) male mice via intranasal delivery of an mRNA encoding luciferase, using in vivo bioluminescence imaging.

RESULTS

Dynamic light scattering revealed that all LNP formulations contained particles with an average diameter of <100 nm and a polydispersity index of <0.2. Human airway epithelial cell lines in culture internalized LNPs with differential GFP transfection efficiencies (73-97%). The lead formulation LNP6 entrapping GFP or Nuc-GFP mRNA demonstrated the highest transfection efficiency (97%). Administration of LNP-GFP siRNA resulted in a significant reduction of GFP protein expression. For in vivo studies, intranasal delivery of LNPs containing helper lipids (DSPC, DOPC, ESM or DOPS) with luciferase mRNA showed significant increase in luminescence expression in nasal cavity and lungs by at least 10 times above baseline control.

CONCLUSION

LNP formulations enable the delivery of RNA payloads into human airway epithelial cells, and in the murine respiratory system; they can be delivered to nasal mucosa and lower respiratory tract via intranasal delivery. The composition of helper lipids in LNPs crucially modulates transfection efficiencies in airway epithelia, highlighting their importance in effective delivery of therapeutic products for airways diseases.

Prediction of Cognitive Decline for Enrichment of Alzheimer's Disease Clinical Trials

BACKGROUND

A key issue to Alzheimer's disease clinical trial failures is poor participant selection. Participants have heterogeneous cognitive trajectories and many do not decline during trials, which reduces a study's power to detect treatment effects. Trials need enrichment strategies to enroll individuals who are more likely to decline.

OBJECTIVES

To develop machine learning models to predict cognitive trajectories in participants with early Alzheimer's disease and presymptomatic individuals over 24 and 48 months respectively.

DESIGN

Prognostic machine learning models were trained from a combination of demographics, cognitive tests, APOE genotype, and brain imaging data.

SETTING

Data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), National Alzheimer's Coordinating Center (NACC), Open Access Series of Imaging Studies (OASIS-3), PharmaCog, and a Phase 3 clinical trial in early Alzheimer's disease were used for this study.

PARTICIPANTS

A total of 2098 participants who had demographics, cognitive tests, APOE genotype, and brain imaging data, as well as follow-up visits for 24-48 months were included.

MEASUREMENTS

Baseline magnetic resonance imaging, cognitive tests, demographics, and APOE genotype were used to separate decliners, defined as individuals whose CDR-Sum of Boxes scores increased during a predefined time window, from stable individuals. A prognostic model to predict decline at 24 months in early Alzheimer's disease was trained on 1151 individuals who had baseline diagnoses of mild cognitive impairment and Alzheimer's dementia from ADNI and NACC. This model was validated on 115 individuals from a placebo arm of a Phase 3 clinical trial and 76 individuals from the PharmaCog dataset. A second prognostic model to predict decline at 48 months in presymptomatic populations was trained on 628 individuals from ADNI and NACC who were cognitively unimpaired at baseline. This model was validated on 128 individuals from OASIS-3.

RESULTS

The models achieved up to 79% area under the curve (cross-validated and out-of-sample). Power analyses showed that using prognostic models to recruit enriched cohorts of predicted decliners can reduce clinical trial sample sizes by as much as 51% while maintaining the same detection power.

CONCLUSIONS

Prognostic tools for predicting cognitive decline and enriching clinical trials with participants at the highest risk of decline can improve trial quality, derisk endpoint failures, and accelerate therapeutic development in Alzheimer's disease.

Dormant spores sense amino acids through the B subunits of their germination receptors

Bacteria from the orders Bacillales and Clostridiales differentiate into stress-resistant spores that can remain dormant for years, yet rapidly germinate upon nutrient sensing. How spores monitor nutrients is poorly understood but in most cases requires putative membrane receptors. The prototypical receptor from Bacillus subtilis consists of three proteins (GerAA, GerAB, GerAC) required for germination in response to L-alanine. GerAB belongs to the Amino Acid-Polyamine-Organocation superfamily of transporters. Using evolutionary co-variation analysis, we provide evidence that GerAB adopts a structure similar to an L-alanine transporter from this superfamily. We show that mutations in gerAB predicted to disrupt the ligand-binding pocket impair germination, while mutations predicted to function in L-alanine recognition enable spores to respond to L-leucine or L-serine. Finally, substitutions of bulkier residues at these positions cause constitutive germination. These data suggest that GerAB is the L-alanine sensor and that B subunits in this broadly conserved family function in nutrient detection.

SP1.1.13Assessing quantitative FIT within the colorectal two-week wait pathway as a triage tool to focus endoscopy services

Aims

Quantitative Faecal Immunochemical test (qFIT) is highly specific for luminal colonic pathology. This study models the potential impact on health care services of its introduction as a tool of triage for the 2-week wait referrals pathway. The Model utilises the recently published NICEFIT tudy.

Methods

All symptoms and results for patients within the colorectal two-week wait pathway are prospectively collated into a relational database. We modelled the impact of introducing targeted FIT testing to those patients without anaemia, rectal mass or overt rectal bleeding. Based on the recent NICEFIT Study, we set a population positivity value of 37% at 2µg/g with sensitivity of identifying colorectal cancer of 97%.

Results

4240 patients were referred in 12 months up to till July 2019. 1333 referrals met the modelled criteria. These 1333 patient events generated 1619 investigations in 1227 patients. Malignancy was found in 4.3% of the investigated referrals (2.8% colorectal, 1.5% extracolonic). By applying FIT to the selected demographics with a positive value of 37%, the number of colonoscopies would fall by 63% (from 815 to 303) with estimated cost saving of £192,000. The FIT negative group would be investigated by selective cross-sectional imaging, with selected use of endoscopy as needed.

Conclusion

The high sensitivity of FIT permits its application as a screening tool in selected symptomatic patients. This can reduce the number of colonoscopies performed by almost 63% within a defined patient group. This would reduce the waiting time for positive high-risk patients as well as cutting overall costs.

EP.TU.296A Significant Difference in Cancer Proportions Between Two Modelled Cohorts Investigated by 2-WeekWait (2WW) Colorectal referral pathway

Aim

To compare the proportions of malignancy between two modelled cohorts of referred and investigated by our colorectal 2 WW referrals pathway.

Methods

Two modelled cohorts were analysed from our prospectively maintained colorectal 2WW referrals database from August 2018 to July 2019. One cohort (group A) included patients without anemia, rectal mass or overt rectal bleeding. The other (group B) included the rest of referrals. Data collected and analysed in each group included total numbers of referrals, investigated referrals and malignancy proportion in each group. One tailed Z test was used to analysis statistical difference.

Results

4240 referrals were made to our colorectal 2 WW pathway during the given period. 1333 (31%) were group A and 2907 (69%) were group B. Total number of patients investigated in group A was 1227, of those only 34 (2.8%) were colorectal cancer and 18 (1.5%) were extracolonic cancer. One the other hand, 2705 patients were investigated in group B, colorectal malignancy were found in 142 (5.3%) patients and 33 (1.2%) were extracolonic. There was a significant difference (p &lt; 0.05) in total number of malignancies between Group A (53/4.3%) and Group B (175/6.5%).

Conclusion

While the 2 Week-Wait referral pathway plays an important role in rapid testing and identifying colorectal cancer, there was a difference between malignancy distribution within the referrals. this difference doesn’t reflect a clinical significance but it can be a good stratification tool.

Genetic rearrangement during site specific integration event facilitates cell line development of a bispecific molecule

Site specific integration (SSI) expression systems offer robust means of generating highly productive and stable cell lines for traditional monoclonal antibodies. As complex modalities such as antibody‐like molecules comprised of greater than two peptides become more prevalent, greater emphasis needs to be placed on the ability to produce appreciable quantities of the correct product of interest (POI). The ability to screen several transcript stoichiometries could play a large role in ensuring high amounts of the correct POI. Here we illustrate implementation of an SSI expression system with a single site of integration for development and production of a multi‐chain, bi‐specific molecule. A SSI vector with a single copy of all of the genes of interest was initially selected for stable Chinese hamster ovary transfection. While the resulting transfection pools generated low levels of the desired heterodimer, utilizing an intensive clone screen strategy, we were able to identify clones having significantly higher levels of POI. In‐depth genotypic characterization of clones having the desirable phenotype revealed that a duplication of the light chain within the landing pad was responsible for producing the intended molecule. Retrospective transfection pool analysis using a vector configuration mimicking the transgene configuration found in the clones, as well as other vector configurations, yielded more favorable results with respect to % POI. Overall, the study demonstrated that despite the theoretical static nature of the SSI expression system, enough heterogeneity existed to yield clones having significantly different transgene phenotypes/genotypes and support production of a complex multi‐chain molecule.

167 The Experience and Outcomes of Elective Urgent and Cancer Surgery in A District General Hospital in The United Kingdom During Covid-19 Pandemic

Background

Many urgent and elective surgeries were postponed to cope with the Coronavirus disease (COVID-19) pandemic, with latest data found a substantial postoperative mortality risk (25·6%, 18.9%) after emergency and elective surgery, respectively.

Our institution was one of the first trust to offer essential elective surgery using a “COVID-free” designated site during the start of the pandemic.

The aim of this study is to analyse the clinical outcomes of patients who underwent essential elective procedures during the virus outbreak in the UK.

Method

Retrospective analysis of outcomes all patients who had undergone urgent elective and cancer surgery, from 30th March 2020 to 21st May 2020, using an implemented “Super Green Pathway”.

The primary endpoints were 30 days mortality and COVID related morbidities, and the secondary endpoints were surgical related complications and oncological outcomes.

Results

92 patients (Male:45%; Female:55%) across 5 surgical specialties were identified. There was no record of mortality in our cohort. Only 1 patient was tested positive for SARS-CoV-2, 18 days after the initial operation without any pulmonary complications.

Conclusions

It is possible to mitigate the high mortality risk of postoperative complications associated with COVID-19, with no delay to essential surgeries for cancer patients, thus delivering safe practice during the pandemic.

Fc-GDF15 glyco-engineering and receptor binding affinity optimization for body weight regulation

GDF15 is a distant TGF-β family member that induces anorexia and weight loss. Due to its function, GDF15 has attracted attention as a potential therapeutic for the treatment of obesity and its associated metabolic diseases. However, the pharmacokinetic and physicochemical properties of GDF15 present several challenges for its development as a therapeutic, including a short half-life, high aggregation propensity, and protease susceptibility in serum. Here, we report the design, characterization and optimization of GDF15 in an Fc-fusion protein format with improved therapeutic properties. Using a structure-based engineering approach, we combined knob-into-hole Fc technology and N-linked glycosylation site mutagenesis for half-life extension, improved solubility and protease resistance. In addition, we identified a set of mutations at the receptor binding site of GDF15 that show increased GFRAL binding affinity and led to significant half-life extension. We also identified a single point mutation that increases p-ERK signaling activity and results in improved weight loss efficacy in vivo. Taken together, our findings allowed us to develop GDF15 in a new therapeutic format that demonstrates better efficacy and potential for improved manufacturability.

Dissecting the Regulatory Strategies of NF-κB RelA Target Genes in the Inflammatory Response Reveals Differential Transactivation Logics

Nuclear factor κB (NF-κB) RelA is the potent transcriptional activator of inflammatory response genes. We stringently defined a list of direct RelA target genes by integrating physical (chromatin immunoprecipitation sequencing [ChIP-seq]) and functional (RNA sequencing [RNA-seq] in knockouts) datasets. We then dissected each gene’s regulatory strategy by testing RelA variants in a primary-cell genetic-complementation assay. All endogenous target genes require RelA to make DNA-base-specific contacts, and none are activatable by the DNA binding domain alone. However, endogenous target genes differ widely in how they employ the two transactivation domains. Through model-aided analysis of the dynamic time-course data, we reveal the gene-specific synergy and redundancy of TA1 and TA2. Given that post-translational modifications control TA1 activity and intrinsic affinity for coactivators determines TA2 activity, the differential TA logics suggests context-dependent versus context-independent control of endogenous RelA-target genes. Although some inflammatory initiators appear to require co-stimulatory TA1 activation, inflammatory resolvers are a part of the NF-κB RelA core response.

Ngo et al. developed a genetic complementation system for NF-κB RelA that reveals that NF-κB target-gene selection requires high-affinity RelA binding and transcriptional activation domains for gene induction. The synergistic and redundant functions of two transactivation domains define pro-inflammatory and inflammation-response genes.

Discovery and optimization of a novel anti-GUCY2c x CD3 bispecific antibody for the treatment of solid tumors

We report here the discovery and optimization of a novel T cell retargeting anti-GUCY2C x anti-CD3ε bispecific antibody for the treatment of solid tumors. Using a combination of hybridoma, phage display and rational design protein engineering, we have developed a fully humanized and manufacturable CD3 bispecific antibody that demonstrates favorable pharmacokinetic properties and potent in vivo efficacy. Anti-GUCY2C and anti-CD3ε antibodies derived from mouse hybridomas were first humanized into well-behaved human variable region frameworks with full retention of binding and T-cell mediated cytotoxic activity. To address potential manufacturability concerns, multiple approaches were taken in parallel to optimize and de-risk the two antibody variable regions. These approaches included structure-guided rational mutagenesis and phage display-based optimization, focusing on improving stability, reducing polyreactivity and self-association potential, removing chemical liabilities and proteolytic cleavage sites, and de-risking immunogenicity. Employing rapid library construction methods as well as automated phage display and high-throughput protein production workflows enabled efficient generation of an optimized bispecific antibody with desirable manufacturability properties, high stability, and low nonspecific binding. Proteolytic cleavage and deamidation in complementarity-determining regions were also successfully addressed. Collectively, these improvements translated to a molecule with potent single-agent in vivo efficacy in a tumor cell line adoptive transfer model and a cynomolgus monkey pharmacokinetic profile (half-life>4.5 days) suitable for clinical development. Clinical evaluation of PF-07062119 is ongoing.

P3778Long-term outcome of non-pharmacologial treatment of atrial fibrillation in hypertrophic cardiomyopathy: a large single-centre experience

Introduction

Atrial fibrillation (AF) is common in hypertrophic cardiomyopathy (HCM) and is generally associated with a significant deterioration of clinical status. Non-pharmacological treatment such as surgical and catheter ablation has become an established therapy for symptomatic AF but in patients with HCM often having a chronically increased left atrial pressure and extensive atrial cardiomyopathy the long-term outcome is uncertain.

Purpose

The present study aimed to analyse the long-term outcome of AF ablation in HCM and the mechanism of recurrent atrial arrhythmias using high-density mapping systems.

Methods

A total of 65 patients (age 64.5±9.9 years, 42 (64.6%) male) with HCM undergoing AF ablation for symptomatic AF were included in our study. The ablation strategy for catheter ablation included pulmonary vein isolation in all patients and biatrial ablation of complex fractionated electrograms with additional ablation lines if appropriate. In patients with suspected atrial tachycardia (AT) high-density activation and substrate mapping were performed. A surgical ablation at the time of an operative myectomy for left ventricular outflow tract obstruction was performed in 8 (12.3%) patients. The outcome was analysed using clinical assessment, Holter ECG and continuous rhythm monitoring of cardiac implantable electric devices.

Results

Paroxysmal AF was present in 27 (41.6%), persistent AF in 37 (56.9%) and primary AT in 1 (1.5%) patients. The mean left atrial diameter was 54.1±12.5 ml. In 11 (16.9%) patients with AT high-density mapping was used to characterize the mechanism of the ongoing tachycardia. After 1.9±1.2 ablation procedures and a follow-up of 48.5±37.2 months, ablation success was demonstrated in 58.9% of patients. The success rate for paroxysmal and persistent AF was 70.0% and 55.8%, respectively (p=0.023). Of those patients with AT high-density mapping guided ablation was successful in 44.4% of patients. The LA diameter of patients with a successful ablation was smaller (52.2 vs. 58.1 mm; p=0.003).

Conclusion

Non-pharmacological treatment of AF in HCM is effective during long-term follow-up. Paroxysmal AF and a smaller LA diameter are favourable for successful ablation. In patients with complex AT the use of high-density mapping can guide ablation resulting in further ablation success in a reasonable number of patients.

Hedgehog signaling in the airway epithelium of patients with chronic obstructive pulmonary disease

Genome-wide association studies have linked gene variants of the receptor patched homolog 1 (PTCH1) with chronic obstructive pulmonary disease (COPD). However, its biological role in the disease is unclear. Our objective was to determine the expression pattern and biological role of PTCH1 in the lungs of patients with COPD. Airway epithelial-specific PTCH1 protein expression and epithelial morphology were assessed in lung tissues of control and COPD patients. PTCH1 mRNA expression was measured in bronchial epithelial cells obtained from individuals with and without COPD. The effects of PTCH1 siRNA knockdown on epithelial repair and mucous expression were evaluated using human epithelial cell lines. Ptch1^+/− mice were used to assess the effect of decreased PTCH1 on mucous expression and airway epithelial phenotypes. Airway epithelial-specific PTCH1 protein expression was significantly increased in subjects with COPD compared to controls, and its expression was associated with total airway epithelial cell count and thickness. PTCH1 knockdown attenuated wound closure and mucous expression in airway epithelial cell lines. Ptch1^+/− mice had reduced mucous expression compared to wildtype mice following mucous induction. PTCH1 protein is up-regulated in COPD airway epithelium and may upregulate mucous expression. PTCH1 provides a novel target to reduce chronic bronchitis in COPD patients.

Glyco-engineered Long Acting FGF21 Variant with Optimal Pharmaceutical and Pharmacokinetic Properties to Enable Weekly to Twice Monthly Subcutaneous Dosing

Pharmacological administration of FGF21 analogues has shown robust body weight reduction and lipid profile improvement in both dysmetabolic animal models and metabolic disease patients. Here we report the design, optimization, and characterization of a long acting glyco-variant of FGF21. Using a combination of N-glycan engineering for enhanced protease resistance and improved solubility, Fc fusion for further half-life extension, and a single point mutation for improving manufacturability in Chinese Hamster Ovary cells, we created a novel FGF21 analogue, Fc-FGF21[R19V][N171] or PF-06645849, with substantially improved solubility and stability profile that is compatible with subcutaneous (SC) administration. In particular, it showed a low systemic clearance (0.243 mL/hr/kg) and long terminal half-life (~200 hours for intact protein) in cynomolgus monkeys that approaches those of monoclonal antibodies. Furthermore, the superior PK properties translated into robust improvement in glucose tolerance and the effects lasted 14 days post single SC dose in ob/ob mice. PF-06645849 also caused greater body weight loss in DIO mice at lower and less frequent SC doses, compared to previous FGF21 analogue PF-05231023. In summary, the overall PK/PD and pharmaceutical profile of PF-06645849 offers great potential for development as weekly to twice-monthly SC administered therapeutic for chronic treatment of metabolic diseases.

Establishing in vitro in vivo correlations to screen monoclonal antibodies for physicochemical properties related to favorable human pharmacokinetics

Implementation of in vitro assays that correlate with in vivo human pharmacokinetics (PK) would provide desirable preclinical tools for the early selection of therapeutic monoclonal antibody (mAb) candidates with minimal non-target-related PK risk. Use of these tools minimizes the likelihood that mAbs with unfavorable PK would be advanced into costly preclinical and clinical development. In total, 42 mAbs varying in isotype and soluble versus membrane targets were tested in in vitro and in vivo studies. MAb physicochemical properties were assessed by measuring non-specific interactions (DNA- and insulin-binding ELISA), self-association (affinity-capture self-interaction nanoparticle spectroscopy) and binding to matrix-immobilized human FcRn (surface plasmon resonance and column chromatography). The range of scores obtained from each in vitro assay trended well with in vivo clearance (CL) using both human FcRn transgenic (Tg32) mouse allometrically projected human CL and observed human CL, where mAbs with high in vitro scores resulted in rapid CL in vivo. Establishing a threshold value for mAb CL in human of 0.32 mL/hr/kg enabled refinement of thresholds for each in vitro assay parameter, and using a combinatorial triage approach enabled the successful differentiation of mAbs at high risk for rapid CL (unfavorable PK) from those with low risk (favorable PK), which allowed mAbs requiring further characterization to be identified. Correlating in vitro parameters with in vivo human CL resulted in a set of in vitro tools for use in early testing that would enable selection of mAbs with the greatest likelihood of success in the clinic, allowing costly late-stage failures related to an inadequate exposure profile, toxicity or lack of efficacy to be avoided.

Site Selection: a Case Study in the Identification of Optimal Cysteine Engineered Antibody Drug Conjugates

As the antibody drug conjugate (ADC) community continues to shift towards site-specific conjugation technology, there is a growing need to understand how the site of conjugation impacts the biophysical and biological properties of an ADC. In order to address this need, we prepared a carefully selected series of engineered cysteine ADCs and proceeded to systematically evaluate their potency, stability, and PK exposure. The site of conjugation did not have a significant influence on the thermal stability and in vitro cytotoxicity of the ADCs. However, we demonstrate that the rate of cathepsin-mediated linker cleavage is heavily dependent upon site and is closely correlated with ADC hydrophobicity, thus confirming other recent reports of this phenomenon. Interestingly, conjugates with high rates of cathepsin-mediated linker cleavage did not exhibit decreased plasma stability. In fact, the major source of plasma instability was shown to be retro-Michael mediated deconjugation. This process is known to be impeded by succinimide hydrolysis, and thus, we undertook a series of mutational experiments demonstrating that basic residues located nearby the site of conjugation can be a significant driver of succinimide ring opening. Finally, we show that total antibody PK exposure in rat was loosely correlated with ADC hydrophobicity. It is our hope that these observations will help the ADC community to build "design rules" that will enable more efficient prosecution of next-generation ADC discovery programs.

Liability for providing a prognosis in surgical practice

The common law's development of the doctrine of informed consent has progressively imposed broader obligations on surgeons to provide patients with information about the surgical and alternative treatment choices available. Prognosis is critical because the patient cannot provide informed consent without information about the likely evolution of the physiological or pathological processes involved in the surgery under consideration. But does the duty of care that a surgeon owes a patient require a precise prognosis to be given in every case? A recent decision of the Court of Appeal considers that question.