High Clinical Failure Rate Research Articles

630. ENDOSCOPIC MANAGEMENT OF DELAYED-GASTRIC-EMPTYING AFTER ESOPHAGECTOMY IN A TERTIARY REFERRAL CENTER: COMPARISON BETWEEN DIFFERENT ENDOSCOPIC PROCEDURES

Abstract Background Delayed Gastric Emptying (DGE) after Esophagectomy with a gastric conduit is a complication that occurs in 15-39% of patients. It is associated with short and long-term complications and with a poor quality of life. Intra-Pyloric Injection of Botulinum Toxin (BT), Pyloric Pneumatic Dilation (PD), and combination of these two techniques (BTPD) in the same session, represent the main endoscopic procedures, but comparative data are currently unavailable. Methods We retrospectively analyzed prospectively collected data on all consecutive patients with DGE after esophagectomy endoscopically treated from December 2018 to November 2023. DGE was classified based on the onset time (early/late), and the Gastric Outlet Obstruction Score (GOOS) was used for clinical staging. All BT patients received 200UI of toxin, while those PD patients have been dilated up to 20mm. Technical success (TS) was defined as the completion of the procedure, clinical success (CS) as achieving a GOOS of ≥2, and recurrence as the need for endoscopic/surgical treatment in patients who achieved CS. Adverse events (AEs) were classified using the AGREE classification. Results 34 patients (82.4% male, 94.1% Ivor-Lewis, divided as follow: 13 (38.2%)BTPD-group, 12 (35.3%)BT-group and 9(26.5%)PD-group. Median follow-up was of 170 days (IQR 67-604), with no differences between the three groups. No statistically significant differences were found in the baseline characteristics among the three groups (e.g.surgical pyloromyotomy, neoadjuvant treatments). Despite identical TS (100%), BT-group exhibited a higher rate of clinical failure (25%) compared to the other groups (p=0.03). No difference in the recurrence rate was observed between the three groups (p=0.47). Dysfunction analysis showed that BTPD-group was characterized by a significatively shorter median time to refeeding of 1 day (IQR 1) compared to the other two groups (log-rank test p=0.0051). No AEs procedures related were recorded. Conclusions Our study reveals that BT is associated with a considerable rate of clinical failure, and that the combined BTPD treatment may offer a more rapid clinical success, maintaining an equivalent safety profile. Further prospective studies are needed to validate these findings.

A new evaluation system for drug-microbiota interactions.

The drug response phenotype is determined by a combination of genetic and environmental factors. The high clinical conversion failure rate of gene-targeted drugs might be attributed to the lack of emphasis on environmental factors and the inherent individual variability in drug response (IVDR). Current evidence suggests that environmental variables, rather than the disease itself, are the primary determinants of both gut microbiota composition and drug metabolism. Additionally, individual differences in gut microbiota create a unique metabolic environment that influences the in vivo processes underlying drug absorption, distribution, metabolism, and excretion (ADME). Here, we discuss how gut microbiota, shaped by both genetic and environmental factors, affects the host's ADME microenvironment within a new evaluation system for drug-microbiota interactions. Furthermore, we propose a new top-down research approach to investigate the intricate nature of drug-microbiota interactions in vivo. This approach utilizes germ-free animal models, providing foundation for the development of a new evaluation system for drug-microbiota interactions.

Ex-vivo drug screening of surgically resected glioma stem cells to replace murine avatars and provide personalise cancer therapy for glioblastoma patients

With diminishing returns and high clinical failure rates from traditional preclinical and animal-based drug discovery strategies, more emphasis is being placed on alternative drug discovery platforms. Ex vivo approaches represent a departure from both more traditional preclinical animal-based models and clinical-based strategies and aim to address intra-tumoural and inter-patient variability at an earlier stage of drug discovery. Additionally, these approaches could also offer precise treatment stratification for patients within a week of tumour resection in order to direct tailored therapy. One tumour group that could significantly benefit from such ex vivo approaches are high-grade gliomas, which exhibit extensive heterogeneity, cellular plasticity and therapy-resistant glioma stem cell (GSC) niches. Historic use of murine-based preclinical models for these tumours has largely failed to generate new therapies, resulting in relatively stagnant and unacceptable survival rates of around 12-15 months post-diagnosis over the last 50 years. The near universal use of DNA damaging chemoradiotherapy after surgical resection within standard-of-care (SoC) therapy regimens provides an opportunity to improve current treatments if we can identify efficient drug combinations in preclinical models that better reflect the complex inter-/intra-tumour heterogeneity, GSC plasticity and inherent DNA damage resistance mechanisms. We have therefore developed and optimised a high-throughput ex vivo drug screening platform; GliExP, which maintains GSC populations using immediately dissociated fresh surgical tissue. As a proof-of-concept for GliExP, we have optimised SoC therapy responses and screened 30+ small molecule therapeutics and preclinical compounds against tumours from 18 different patients, including multi-region spatial heterogeneity sampling from several individual tumours. Our data therefore provides a strong basis to build upon GliExP to incorporate combination-based oncology therapeutics in tandem with SoC therapies as an important preclinical alternative to murine models (reduction and replacement) to triage experimental therapeutics for clinical translation and deliver rapid identification of effective treatment strategies for individual gliomas.

Compound Absorption in Polymer Devices Impairs the Translatability of Preclinical Safety Assessments.

Organotypic and microphysiological systems (MPS) that can emulate the molecular phenotype and function of human tissues, such as liver, are increasingly used in preclinical drug development. However, despite their improved predictivity, drug development success rates have remained low with most compounds failing in clinical phases despite promising preclinical data. Here, it is tested whether absorption of small molecules to polymers commonly used for MPS fabrication can impact preclinical pharmacological and toxicological assessments and contribute to the high clinical failure rates. To this end, identical devices are fabricated from eight different MPS polymers and absorption of prototypic compounds with different physicochemical properties are analyzed. It is found that overall absorption is primarily driven by compound hydrophobicity and the number of rotatable bonds. However, absorption can differ by >1000-fold between polymers with polydimethyl siloxane (PDMS) being most absorptive, whereas polytetrafluoroethylene (PTFE) and thiol-ene epoxy (TEE) absorbed the least. Strikingly, organotypic primary human liver cultures successfully flagged hydrophobic hepatotoxins in lowly absorbing TEE devices at therapeutically relevant concentrations, whereas isogenic cultures in PDMS devices are resistant, resulting in false negative safety signals. Combined, these results can guide the selection of MPS materials and facilitate the development of preclinical assays with improved translatability.

Genesis of Clinical Trial Failure: A Review

Clinical Trials are often labelled as failure or negative when the anticipated results are not observed. The negative results can be due to multiple factors such as primary and secondary endpoints not being met higher incidence of adverse reactions, and sluggish recruitment of trial subjects due to stringent inclusion and exclusion criteria, higher dropout rates due to changed biochemical parameters such as raised liver or hepatic enzymes. Trial Failures are reported globally but within developing countries, the reports are meagre. Inclusion in trials imposes a financial burden on patients and hence dropout rates proportionately increase. Recruitment of patients is often better in open trials as compared to blind studies as drug awareness imposes better confidence in the recruited subjects. The oncology trials that use biomarkers in patient selection have higher overall success probabilities than trials without biomarkers. Complexities in drug development and the inherent uncertainties in medical research also play an important role in a high rate of clinical trial failures.

Ex-vivo drug screening of surgically resected glioma stem cells to replace murine avatars and provide personalise cancer therapy for glioblastoma patients.

With diminishing returns and high clinical failure rates from traditional preclinical and animal-based drug discovery strategies, more emphasis is being placed on alternative drug discovery platforms. Ex vivo approaches represent a departure from both more traditional preclinical animal-based models and clinical-based strategies and aim to address intra-tumoural and inter-patient variability at an earlier stage of drug discovery. Additionally, these approaches could also offer precise treatment stratification for patients within a week of tumour resection in order to direct tailored therapy. One tumour group that could significantly benefit from such ex vivo approaches are high-grade gliomas, which exhibit extensive heterogeneity, cellular plasticity and therapy-resistant glioma stem cell (GSC) niches. Historic use of murine-based preclinical models for these tumours has largely failed to generate new therapies, resulting in relatively stagnant and unacceptable survival rates of around 12-15 months post-diagnosis over the last 50 years. The near universal use of DNA damaging chemoradiotherapy after surgical resection within standard-of-care (SoC) therapy regimens provides an opportunity to improve current treatments if we can identify efficient drug combinations in preclinical models that better reflect the complex inter-/intra-tumour heterogeneity, GSC plasticity and inherent DNA damage resistance mechanisms. We have therefore developed and optimised a high-throughput ex vivo drug screening platform; GliExP, which maintains GSC populations using immediately dissociated fresh surgical tissue. As a proof-of-concept for GliExP, we have optimised SoC therapy responses and screened 30+ small molecule therapeutics and preclinical compounds against tumours from 18 different patients, including multi-region spatial heterogeneity sampling from several individual tumours. Our data therefore provides a strong basis to build upon GliExP to incorporate combination-based oncology therapeutics in tandem with SoC therapies as an important preclinical alternative to murine models (reduction and replacement) to triage experimental therapeutics for clinical translation and deliver rapid identification of effective treatment strategies for individual gliomas.

Predictive factors of selective transarterial embolization failure in acute renal bleeding: a single-center experience.

Transarterial embolization of renal artery branches (RTE) is a minimally invasive procedure commonly performed in life-threatening renal bleeding of different etiologies. Despite the widespread use of RTE, no consensus guidelines are currently available. Our aim was to investigate clinical and technical efficacy and to identify potential predictors for clinical failure of this procedure. All the RTE procedures performed in our Interventional Radiology unit in last 10years were retrospectively collected and analyzed. All selected patients underwent both pre-procedural computed tomography angiography (CTA) and post-procedural CTA within 30days. Clinical success was considered as primary endpoint. Demographic, laboratory, and diagnostic findings predictive of clinical failure of RTE were identified. Over a total of 51 patients enrolled, 27 (53%) were females and 33 (64.7%) had a renal bleeding of iatrogenic origin. Technical and clinical success was 100% and 80.4%, respectively. Hematoma volumes > 258.5 cm3 measured at CTA, higher pre- and post-procedural serum creatinine (Scr) levels, an increase in Scr value > 0.135mg/dl after the procedure, a worse post-procedural estimated glomerular filtration rate (eGFR), a post-procedural reduction of eGFR < 3.350ml/min, and a post-procedural reduction of platelet count (PLT) > 46.50 × 103/mmc showed a significantly higher rate of clinical failure. RTE is a safe and effective procedure in the management of acute renal bleeding of various origins. Hematoma volume, Scr, PLT, and eGFR values were found to be predictive factors of poor clinical outcome and should be closely monitored.

Acinetobacter baumannii in the critically ill: complex infections get complicated.

Acinetobacter baumannii is increasingly associated with various epidemics, representing a serious concern due to the broad level of antimicrobial resistance and clinical manifestations. During the last decades, A. baumannii has emerged as a major pathogen in vulnerable and critically ill patients. Bacteremia, pneumonia, urinary tract, and skin and soft tissue infections are the most common presentations of A. baumannii, with attributable mortality rates approaching 35%. Carbapenems have been considered the first choice to treat A. baumannii infections. However, due to the widespread prevalence of carbapenem-resistant A. baumannii (CRAB), colistin represents the main therapeutic option, while the role of the new siderophore cephalosporin cefiderocol still needs to be ascertained. Furthermore, high clinical failure rates have been reported for colistin monotherapy when used to treat CRAB infections. Thus, the most effective antibiotic combination remains disputed. In addition to its ability to develop antibiotic resistance, A. baumannii is also known to form biofilm on medical devices, including central venous catheters or endotracheal tubes. Thus, the worrisome spread of biofilm-producing strains in multidrug-resistant populations of A. baumannii poses a significant treatment challenge. This review provides an updated account of antimicrobial resistance patterns and biofilm-mediated tolerance in A. baumannii infections with a special focus on fragile and critically ill patients.

I CAN HANDLE IRREPARABLE CUFF TEAR WITH REHABILITATION/I AM SURE THAT YOU CAN’T HANDLE ALL WITH REHAB

Rotator cuff tears (RCT) are one of the most commonly treated orthopaedic pathologies, yet controversy exists regarding the management of these injuries. Irreparable rotator cuff tears are unpredictable with respect to their clinical presentation. The spectrum of pain and functional disability varies widely. Rehabilitation protocol is always the first solution in treating irreparable cuff tears, but non-functional and painful shoulders (e.g., arthrosis) is an indication for surgery. Can we ask ourselves a question: where lies the limit of trying “persistent” surgical repair of massive irreparable RC lesions? There is a lack of high-quality comparative studies to guide treatment recommendations. Physical therapy compared to surgery is associated with a lower improvement in perceived functional outcome and higher clinical failure rate. However, there is insufficient evidence to establish an evidence-based treatment algorithm for MRCTs. Treatment is based on patient factors and associated pathology and includes personal experience and data from case series. It has to be underlined that the winner is always team physiotherapist/surgeon, and their cooperation is crucial at all stages of therapy

Biomechanical Comparison of Adjustable-Loop Femoral Cortical Suspension Devices for Soft Tissue ACL Reconstruction

Several new adjustable-loop devices (ALDs) for anterior cruciate ligament reconstruction (ACLR) have not been tested in vitro. To compare the biomechanical performances of 5 ALDs under a high cyclic load and forces representative of the return-to-play conditions seen in the recovering athlete. Controlled laboratory study. A total of 10 devices for each of 5 chosen ALDs (UltraButton [Smith & Nephew], RigidLoop [DePuy Mitek], ProCinch [Stryker], TightRope [Arthrex], and ToggleLoc [Biomet]) were tested in a device-only model. The devices were secured to a servohydraulic test machine and preconditioned from 10 to 75 N at a rate of 0.5 Hz for 20 cycles. They were then subjected to high cyclic forces (100-500 N for 4000 cycles) and subsequently pulled to failure at 50 mm/min. The preconditioning displacement, permanent deformation, cumulative peak displacement, stiffness coefficient, and load to failure data were collected. The UltraButton displayed the greatest preconditioning displacement (0.22 ± 0.20 mm), followed by the RigidLoop (0.11 ± 0.03 mm), ProCinch (0.07 ± 0.04 mm), TightRope (0.07 ± 0.02 mm), and ToggleLoc (0.02 ± 0.03 mm). The TightRope displayed the greatest permanent deformation (3.19 ± 1.03 mm) followed by the UltraButton (2.14 ± 0.92 mm), ToggleLoc (2.02 ± 1.09 mm), RigidLoop (1.67 ± 0.1 mm), and ProCinch (1.38 ± 0.18 mm). The TightRope displayed the greatest cumulative peak displacement (3.69 ± 1.03 mm) followed by the UltraButton (2.46 ± 0.92 mm), ToggleLoc (2.37 ± 1.08 mm), RigidLoop (2.01 ± 0.1 mm), and ProCinch (1.75 ± 0.19 mm). The UltraButton displayed the largest stiffness coefficient (1347.22 ± 136.33 N/mm) followed by the RigidLoop (1325.4 ± 116.37 N/mm), ToggleLoc (1216.62 ± 131.32 N/mm), ProCinch (1155.56 ± 88.04), and TightRope (848.48 ± 31.94). The ToggleLoc displayed the largest load to failure (1874.42 ± 101.08 N) followed by the RigidLoop (1614.12 ± 129.11 N), UltraButton (1391.69 ± 142.04 N), ProCinch (1384.85 ± 58.62 N), and TightRope (991.8 ± 51.1 N.). The 5 ALDs exhibited different biomechanical properties. None of them had peak cumulative displacements for which the confidence interval lay above 3 mm, thus no single device was determined to have a higher rate of clinical failure compared with the others. ALD choice may affect biomechanics after ACLR.

The Clinical Outcome of Early Periprosthetic Joint Infections Caused by Staphylococcus epidermidis and Managed by Surgical Debridement in an Era of Increasing Resistance.

A risk factor for the failure of surgical debridement in patients with early periprosthetic joint infections (PJI) is the presence of multidrug-resistant microorganisms. Staphylococcus epidermidis is one of the most isolated microorganisms in PJI and is associated with emerging resistance patterns. We aimed to assess the antibiotic resistance patterns of S. epidermidis in early PJIs treated with surgical debridement and correlate them to clinical outcomes. A retrospective multicentre observational study was conducted to evaluate patients with an early PJI (within 3 months after the index arthroplasty) by S. epidermidis with at least two positive intraoperative cultures. Clinical failure was defined as the need for additional surgical intervention or antibiotic suppressive therapy to control the infection. A total of 157 patients were included. The highest rate of resistance was observed for methicillin in 82% and ciprofloxacin in 65% of the cases. Both were associated with a higher rate of clinical failure (41.2% vs. 12.5% (p 0.048) and 47.3% vs. 14.3% (p 0.015)), respectively. Furthermore, 70% of the cases had reduced susceptibility to vancomycin (MIC ≥ 2), which showed a trend towards a higher failure rate (39.6% vs. 19.0%, NS). Only 7% of the cases were rifampin-resistant. Only the resistance to fluoroquinolones was an independent risk factor for clinical failure in the multivariate analysis (OR 5.45, 95% CI 1.67-17.83). S. epidermidis PJIs show a high rate of resistance. Resistance to fluoroquinolones is associated with clinical failure. Alternative prophylactic antibiotic regimens and optimising treatment strategies are needed to improve clinical outcomes.

647. Cefepime Versus Carbapenems for the Treatment of ESBL-producing Enterobacterales among Non-blood Isolates

Abstract Background The incidence of organisms with extended-spectrum beta-lactamases (ESBLs) is increasing. The data for using cefepime in ESBL-producing Enterobacterales infections is conflicting. More favorable outcomes are likely if minimum inhibitory concentrations (MICs) &amp;lt; 2 mcg/mL. The aim of this study is to compare the efficacy of cefepime versus carbapenems for ESBL-producing, non-bloodstream Enterobacterales infections. Methods This study was a single-center retrospective cohort study of patients who received cefepime or a carbapenem for at least 72 hours for the definitive treatment of an ESBL-producing Enterobacterales non-bloodstream infection between Jan. 1, 2011 and Sept. 30, 2021. ESBL production was identified if the isolate either had a positive confirmatory ESBL test from VITEK 2 (bioMérieux) or phenotypic resistance to ceftriaxone. Isolates had to have a MIC &amp;lt; 2 mcg/mL to cefepime or be susceptible to carbapenems. Isolates with a cefepime MIC 4-8 mcg/mL were not included due to likely higher rates of treatment failure. The primary endpoint was clinical failure, defined as persistence of symptoms requiring escalation of therapy or death. Descriptive statistics were used to compare groups. A univariate analysis and odds ratio was calculated for clinical outcomes. Results One hundred patients were included. Twenty-two patients received cefepime and 78 received a carbapenem. Table 1 describes patient characteristics and clinical outcomes. Most patients had a urinary tract infection (UTI) (94%). More patients receiving cefepime were admitted to the intensive care unit (40.9% versus 15.4%). Treatment with cefepime displayed higher rates of clinical failure when compared to treatment with carbapenems (13.6% versus 6.4%). Cohen’s d-test for clinical failure was 0.46, indicating a medium effect. Conclusion Based on our analysis, cefepime may have higher rates of clinical failure when compared to carbapenem treatment for ESBL-producing Enterobacterales. Most of our patients were treated for UTIs and the sample size for both arms were limited, particularly for the cefepime arm. Further research is needed to confirm the role of cefepime as a carbapenem-sparing option in the treatment of these drug-resistant infections. Disclosures Madeline King, PharmD, Shionogi: Honoraria|Tetraphase: speakers' bureau.

Design of a Novel Kresling Origami Lumbar Disc Replacement for Degenerative Disc Disease

Though it is normal for spinal discs to show signs of wear and deterioration with age, this process may result in degenerative disc disease (DDD), causing pain, stiffness, and even physical deformity. DDD affects 40% of people aged 40 years old and increases to 80% for those aged 80 years or older. Lumbar disc replacements (LDRs) are commonly used as a surgical intervention for DDD. Unfortunately, currently marketed LDRs present a myriad of problems that lead to a clinical failure rate of up to 26% at a two-year follow-up report. Patients with underlying conditions such as diabetes experience even higher rates of clinical failure. Root causes for complications include incorrect sizing of the implant, lack of mobility, and material choices that do not allow for proper integration into the body. Our project proposes a novel design that will replicate the properties of natural lumbar discs and mitigate these complications. This design consists of porous titanium (Ti-6AL-4V)/chitosan sponge composite endplates that can be loaded with compounds to prevent infection and accelerate fusion with the vertebrae surrounding the LDR. A polyurethane Kresling Origami-inspired insert will be sandwiched in between the endplates, allowing the LDR to adjust its size for optimal fitting and provide shock absorption, stability, and mobility to the spinal column. Methods for executing this design are also proposed, along with mechanical and biological tests to be conducted. This paper is the first part in a series of studies that will culminate in assembling and testing the final LDR.

3D bioprinting as an emerging standard for cancer modeling and drug testing.

Neoplastic diseases are a leading cause of death worldwide accounting for 10 million mortalities in 2020. Despite constantly revised and improved therapeutic regimens, the number of fatal cases increases annually. Therefore, better preclinical models are needed to study tumorigenesis and assess new drugs. Although 2D cell cultures significantly contributed to the understanding of tumor biology, they present high clinical trial failure rates. This is because 2D cannot reproduce the intricate tumor architecture and multiple cell interactions.Nevertheless, novel 3D biofabrication technologies and 3D bioprinted tumor models successfully mirror the complexity of human tumors and are currently revolutionizing preclinical cancer research by using live cells encapsulated in a variety of biomaterials. Since bioinks possess excellent chemical and biophysical ECM-like characteristics, this allows for recreation of the intricate tumor-specific architecture with an unmatched level of control, accuracy, and reproducibility. The resulting cellular constructs approximate actual pathological microenvironment of the tumor and some key in vivo processes such as proliferation, differentiation, and metastasis. 3D bioprinted models of glioblastoma, cervical, ovarian, and breast cancer are already being successfully used to study tumorigenesis and cellular response to antitumor drugs. This success showcases the potential of these novel experimental platforms.

Generation of 3D Spheroids Using a Thiol-Acrylate Hydrogel Scaffold to Study Endocrine Response in ER+ Breast Cancer.

Culturing cancer cells in a three-dimensional (3D) environment better recapitulates in vivo conditions by mimicking cell-to-cell interactions and mass transfer limitations of metabolites, oxygen, and drugs. Recent drug studies have suggested that a high rate of preclinical and clinical failures results from mass transfer limitations associated with drug entry into solid tumors that 2D model systems cannot predict. Droplet microfluidic devices offer a promising alternative to grow 3D spheroids from a small number of cells to reduce intratumor heterogeneity, which is lacking in other approaches. Spheroids were generated by encapsulating cells in novel thiol–acrylate (TA) hydrogel scaffold droplets followed by on-chip isolation of single droplets in a 990- or 450-member trapping array. The TA hydrogel rapidly (∼35 min) polymerized on-chip to provide an initial scaffold to support spheroid development followed by a time-dependent degradation. Two trapping arrays were fabricated with 150 or 300 μm diameter traps to investigate the effect of droplet size and cell seeding density on spheroid formation and growth. Both trapping arrays were capable of ∼99% droplet trapping efficiency with ∼90% and 55% cellular encapsulation in trapping arrays containing 300 and 150 μm traps, respectively. The oil phase was replaced with media ∼1 h after droplet trapping to initiate long-term spheroid culturing. The growth and viability of MCF-7 3D spheroids were confirmed for 7 days under continuous media flow using a customized gravity-driven system to eliminate the need for syringe pumps. It was found that a minimum of 10 or more encapsulated cells are needed to generate a growing spheroid while fewer than 10 parent cells produced stagnant 3D spheroids. As a proof of concept, a drug susceptibility study was performed treating the spheroids with fulvestrant followed by interrogating the spheroids for proliferation in the presence of estrogen. Following fulvestrant exposure, the spheroids showed significantly less proliferation in the presence of estrogen, confirming drug efficacy.

Abstract 186: Advances in 3D cell culture analysis: Utilizing novel flow cytometry technology for rapid analysis of intact spheroids

Abstract Cancer cells grown in two dimensional (2D) monolayers are a convenient model to use for basic research and in generating lead candidates in the drug discovery process. However, cells grown in 2D cultures lack many of the structural, biological, and functional attributes of solid tumors, which contributes to the high clinical failure rates for biologic and small molecule drugs. Multicellular three-dimensional (3D) tumor spheroids are advanced models which more faithfully mimic the physiological tumor milieu and is more predictive of therapeutic efficacy than traditional monolayer cultures. However, the inability to generate and to analyze large numbers of intact spheroids with a simplified workflow remains a barrier in the adoption of 3D models for a wide range of applications. To overcome these barriers, we used the Velocyt® large particle flow cytometer (Bennubio) to evaluate spheroid health in a well-established small molecule spheroid killing assay. The Velocyt technology rapidly and gently analyzes particles from 3 to 300 microns and comes with a suite of novel informatics tools purpose built for large particle analysis. To exemplify the use of large particle flow cytometry for the analysis of intact spheroids we generated uniformed-sized spheroids (~180 microns) from the H1650 human lung and HCT116 human colon cancer cell lines using microwell technology. Two to three days after spheroid generation, the spheroids were treated with increasing concentrations of staurosporine and other compounds. Spheroids were harvested at one to three days post treatment (depending on drug treatment) and stained with fluorescent cell viability and apoptotic dyes. Intact spheroids were analyzed for fluorescence and size using the Velocyt flow cytometer and between one and two thousand spheroids were assessed for each treatment in approximately three minutes. In untreated control spheroids, fluorescence was detected in a subpopulation of spheroids consistent with expected low levels of background apoptosis. In treated spheroids, an increase in the mean fluorescence intensity (MFI) of each particle indicated an increase in the number of non-viable and apoptotic cells in each spheroid. MFI increased nearly 6-fold with high concentrations of staurosporine compared to control spheroids, and dead cells were detected in nearly 100% of spheroids that were administered the highest staurosporine concentration. Using the size-based measurement parameters of the Velocyt, we also showed a decrease in overall spheroid size concurrent with increased numbers of spheroid fragments and single cells with increasing drug concentration. These data highlight that the use of 3D cell models combined with the Velocyt large particle flow cytometer is a powerful tool to help advance basic and translational cancer research. Citation Format: John P. O'Rourke, Mathew Saunders, Valerie Sanchez. Advances in 3D cell culture analysis: Utilizing novel flow cytometry technology for rapid analysis of intact spheroids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 186.

Drug Delivery Systems for Cancer Treatment: A Review of Marine-derived Polysaccharides.

Cancer is a disease characterized by uncontrolled cell proliferation and the spread of cells to other tissues and remains one of the worldwide problems waiting to be solved. There are various treatment strategies for cancer, such as chemotherapy, surgery, radiotherapy, and immunotherapy, although it varies according to its type and stage. Many chemotherapeutic agents have limited clinical use due to lack of efficacy, off-target toxicity, metabolic instability, or poor pharmacokinetics. One possible solution to this high rate of clinical failure is to design drug delivery systems that deliver drugs in a controlled and specific manner and are not toxic to normal cells. Marine systems contain biodiversity, including components and materials that can be used in biomedical applications and therapy. Biomaterials such as chitin, chitosan, alginate, carrageenan, fucoidan, hyaluronan, agarose, and ulvan obtained from marine organisms have found use in DDSs today. These polysaccharides are biocompatible, non-toxic, biodegradable, and cost-effective, making them ideal raw materials for increasingly complex DDSs with a potentially regulated release. In this review, the contributions of polysaccharides from the marine environment to the development of anticancer drugs in DDSs will be discussed.

Precision oncology using ex vivo technology: a step towards individualised cancer care?

Despite advances in cancer genomics and the increased use of genomic medicine, metastatic cancer is still mostly an incurable and fatal disease. With diminishing returns from traditional drug discovery strategies, and high clinical failure rates, more emphasis is being placed on alternative drug discovery platforms, such as ex vivo approaches. Ex vivo approaches aim to embed biological relevance and inter-patient variability at an earlier stage of drug discovery, and to offer more precise treatment stratification for patients. However, these techniques also have a high potential to offer personalised therapies to patients, complementing and enhancing genomic medicine. Although an array of approaches are available to researchers, only a minority of techniques have made it through to direct patient treatment within robust clinical trials. Within this review, we discuss the current challenges to ex vivo approaches within clinical practice and summarise the contemporary literature which has directed patient treatment. Finally, we map out how ex vivo approaches could transition from a small-scale, predominantly research based technology to a robust and validated predictive tool. In future, these pre-clinical approaches may be integrated into clinical cancer pathways to assist in the personalisation of therapy choices and to hopefully improve patient experiences and outcomes.

Long-term follow-up of bucket-handle meniscal repairs: chondroprotective effect outweighs high failure risk.

Outcomes after repair of bucket-handle meniscal tears tend to be satisfying in the short-term follow-up. However, the literature is scarce regarding long-term data following repair of bucket-handle meniscal tears. The aim of this study was to assess long-term follow-up outcomes, focusing on knee osteoarthritis (OA) development and failure rate, and determine risk factors associated with failure. This is a retrospective cohort study, including all patients with bucket-handle tears within 4mm of the menisco-synovial junction, who underwent meniscal repair, either isolated or combined with anterior cruciate ligament reconstruction (ACLR) between 2004 and 2015. A combination of all-inside, outside-in, and inside-out repair technique was used in all patients. Patients over 40years old, concomitant multi-ligamentous injuries, and severe cartilage lesions documented intraoperatively were excluded. During the follow-up, a meniscus was considered healed using Barrett's criteria, while knee OA evaluation was performed according to Kellgren-Lawrence (KL) classification using standing knee radiographs. Patients were assessed preoperatively as well as postoperatively in terms of knee function using International Knee Documentation Committee (IKDC) score, Lysholm score, and Knee injury and Osteoarthritis Outcome Score (KOOS). In total, the inclusion criteria were met by 66 patients. Median age at the time of operation was 21.9years (13-39). Median follow-up was 114 (62-176) months. Total failure rate was approximately 33% at median time of 19 (6-39) months. Osteoarthritis was statistically significantly more prevalent in patients with failed repairs (mean KL score: 2.09) in comparison to patients with successful repairs (mean KL score: 0.54) p = 0.001. In addition, successful repairs were associated with higher KOOS score as compared with failed repairs (mean ± SD, 89.6 ± 4.6 vs 77.8 ± 4.9 p < 0.001), higher IKDC score (mean ± SD, 88.2 ± 5.1 vs 79.2 ± 5.2 p < 0.001), and Lysholm score (mean ± SD, 90.3 ± 5.3 vs 78.4 ± 7.8 p < 0.001). Patients with medial meniscus repair had 4.8 higher relative likelihood of failure compared to lateral meniscus [p = 0 .014, OR = 4.8 (95% Cl 1.2, 18.6)]. Patients over 16years old had 5.7 higher relative likelihood of failure [p = 0 .016, OR = 5.7 (95% Cl 0.04, 0.85)]. Concurrent ACLR did not have a significant effect on the postoperative outcomes. A high rate of clinical failure was observed after meniscal repair of bucket-handle tears. However, successful treatment led to lower rates of knee OA development and better knee function, approximately 10 years postoperatively. Meniscal repair of bucket-handle tears is recommended to improve knee function and prevent knee OA in young patients. III.

Adverse loading effects on tribocorrosive degradation of 28 mm metal-on-metal hip replacement bearings

Following the high clinical failure rates of metal-on-metal total hip replacements much work has been undertaken to investigate their poor performance. So called adverse loading scenarios such as acetabular inclination and microseparation have been attributed to indicators for failure of the implants. The ISO hip simulation standards (ISO 14242:1) still rely on gravimetric and ex situ analysis, considering only the total wear during articulation. Live in situ sensing can provide valuable insight into the degradation mechanisms of metallic interfaces under such scenarios. Clinical 28 mm diameter metal-on-metal components were articulated in a full-ISO hip simulator. The bearings were subjected to increasing angles of acetabular inclination and retroversion over short-term periods of articulation. Corrosive degradation was monitored during sliding by means of an in situ three-electrode cell. Changing acetabular inclination from 30° to 50° resulted in greater cathodic shifts in OCP upon the initiation of sliding; from −50 mV to as much as −150 mV. Under anodic polarisation (0 mV vs. Ag/AgCl) the resultant currents at the initiation of sliding also increased significantly with inclination; from approximately 4–10 µA to over 120 µA. Increased retroversion of 20° also resulted in increased anodic currents of 55–60 µA. Changing the nature of articulation demonstrated increased corrosive material loss compared to a standard ISO 14242 profile. The sole use of gravimetric assessment to determine a wear rate for hip replacement bearings under simulation can therefore neglect important degradation mechanisms, such as tribocorrosive loss in devices with metal sliding interfaces.