Utility of Targeted Positron Emission Tomography Imaging to Predict Schwannoma Growth in a Murine Tumor Model.

OBJECTIVE: To identify if targeted positron emission tomography (PET) imaging with radiolabeled antibodies can predict tumor growth rate and ultimate tumor size in a murine flank schwannoma model. STUDY DESIGN: Animal research study. METHODS: Rat schwannoma cells were cultured and implanted into 40 athymic nude mice. Once tumors reached 5 mm in diameter, 30 mice were injected with zirconium-89 labeled antibodies (HER2/Neu, vascular endothelial growth factor receptor 2 (VEGFR2), or IgG isotype). PET/CT was performed, and standardized uptake values (SUV) were recorded. Tumors were serially measured until mice were sacrificed per IACUC protocol. Statistical analysis was performed to measure correlations between SUV values, tumor size, and growth. RESULTS: Mean tumor sizes in mm3 on Day 0 were 144 ± 162 for anti-HER2/Neu, 212 ± 247 for anti-VEGFR2, and 172 ± 204 for IgG isotype groups respectively. Mean growth rates in mm3 /day were 531 ± 250 for HER2, 584 ± 188 for VEGFR2, and 416 ± 163 for the IgG isotype group. For both initial tumor size and growth rates, there was no significant difference between groups. There were significant correlations between maximum tumor volume and both the SUV max in the HER2 group (p = 0.0218, R2 = 0.5020), and we observed significant correlations between growth rate, and SUV values (p = 0.0156, R2 = 0.5394). Respectively, in the anti-VEGFR2 group, there were no significant correlations. CONCLUSION: In a murine schwannoma model, immunotargeted PET imaging with anti-HER2/Neu antibodies predicted tumor growth rate and final tumor size. Laryngoscope, 134:1372-1380, 2024.

Fungal Infections of the External Auditory Canal and Emerging Pathogens.

Fungal infections of the external auditory canal can range from common (otomycosis) to life threatening (necrotizing otitis externa). Proper identification of fungal pathogens is necessary to guide appropriate therapy, and a high index of suspicion for fungal causes of ear canal disease is critical. Fungal pathogens may be an especially important cause of ear canal disease in certain populations, including patients with diabetes, patients recently treated with antibiotics, and immunosuppressed patients. Opportunistic fungal infections of the ear canal are an emerging concern.

Metformin Reduces Tumor Growth in a Murine Flank Schwannoma Model.

HYPOTHESIS: Metformin and aspirin reduce vestibular schwannoma (VS) growth. BACKGROUND: There have been reported associations between patients with VS prescribed metformin and decreased tumor volumetric growth. Aspirin has also been associated with decreased VS growth in animal studies. METHODS: Rat schwannoma cell lines were grown and implanted into 50 athymic nude mice. Tumors were grown to 5 mm, and then mice were injected with either low- or high-dose metformin, aspirin, or saline daily. Tumors were measured until 14 days elapsed or mice demonstrated symptoms such as ulceration, inability to walk, or passed away. RESULTS: There were no significant differences in day 0 tumor sizes between the control and the treatment groups ( p = 0.73). In the low-dose, but not high-dose groups, day 7 volumes were significantly different for both metformin ( p = 0.04) and aspirin ( p = 0.02) compared with placebo. Mean tumor growth rates were 126.6 ± 65.6 mm 3 /day for saline compared with 73.7 ± 29.5 mm 3 /day for low-dose metformin ( p = 0.03) and 68.7 ± 34.8 mm 3 /day for low-dose aspirin ( p = 0.016). There were no significant differences in tumor sizes ( p = 0.59) or growth rates ( p = 0.75) between low-dose metformin and aspirin groups. Low-dose groups had treatment stopped at 14 days, with continued monitoring demonstrating significant increases in tumor growth off treatment for both aspirin ( p = 0.006) and metformin ( p = 0.048). CONCLUSIONS: Metformin treatment significantly reduced VS growth to a similar level as aspirin. Furthermore, when removing both metformin and aspirin treatment, tumor growth significantly increased.

An Intercompany Perspective on Practical Experiences of Predicting, Optimizing and Analyzing High Concentration Biologic Therapeutic Formulations.

Developing high-dose biologic drugs for subcutaneous injection often requires high-concentration formulations and optimizing viscosity, solubility, and stability while overcoming analytical, manufacturing, and administration challenges. To understand industry approaches for developing high-concentration formulations, the Formulation Workstream of the BioPhorum Development Group, an industry-wide consortium, conducted an inter-company collaborative exercise which included several surveys. This collaboration provided an industry perspective, experience, and insight into the practicalities for developing high-concentration biologics. To understand solubility and viscosity, companies desire predictive tools, but experience indicates that these are not reliable and experimental strategies are best. Similarly, most companies prefer accelerated and stress stability studies to in-silico or biophysical-based prediction methods to assess aggregation. In addition, optimization of primary container-closure and devices are pursued to mitigate challenges associated with high viscosity of the formulation. Formulation strategies including excipient selection and application of studies at low concentration to high-concentration formulations are reported. Finally, analytical approaches to high concentration formulations are presented. The survey suggests that although prediction of viscosity, solubility, and long-term stability is desirable, the outcome can be inconsistent and molecule dependent. Significant experimental studies are required to confirm robust product definition as modeling at low protein concentrations will not necessarily extrapolate to high concentration formulations.

Inverted Papilloma of the Middle Ear: Two New Cases and Systematic Review.

Introduction: Inverted papillomas of the middle ear are extremely rare tumors that carry an increased risk of recurrence and malignant transformation. There are currently 59 cases of middle ear inverted papillomas reported in the literature. The objective in this study was to systematically evaluate outcomes regarding middle ear inverted papillomas with respect to demographics, anatomical tumor sites, malignant transformation status, recurrence rate and HPV status. Study Design: Retrospective case series and systematic review. Methods: A systematic review was completed on June 25, 2020 with a search strategy including PubMed, Embase, Scopus and Google Scholar. This revealed 181 articles. Full-text review was completed, and 66 articles were included. 115 articles were eliminated due to duplication of articles from databases, article titles not applicable to the aims of the systematic review and articles describing inverted papilloma of body sites other than middle ear. Discussion: Thirty-one cases of primary inverted papillomas of the middle ear were found in the literature with an additional 26 cases of secondary tumors. Four case reports did not specify primary versus secondary. The malignant transformation rate was 34.4% with a 53.6% recurrence rate. Treatment of middle ear inverted papillomas is primarily surgical with adjuvant radiation therapy considered for patients with recurrence or malignant transformation. Frequent clinical follow up of these patients is critical due to the increased rate of recurrence and malignant transformation. Conclusion: Inverted papillomas of the middle ear are rare tumors that carry a high risk of recurrence and malignant transformation necessitating complete resection and frequent clinical follow up.

Discovery of MK-1462: GLP-1 and Glucagon Receptor Dual Agonist for the Treatment of Obesity and Diabetes.

Peptide-based analogues of the gut-derived incretin hormone, glucagon-like peptide 1 (GLP1), stimulate insulin secretion in a glucose-dependent manner. Currently marketed GLP1 receptor (GLP1R) agonists are safe and effective in the management of Type 2 diabetes but often offer only modest weight loss. This has prompted the search for safe and effective alternatives to enhance the weight loss component of these treatments. We have demonstrated that concomitant activation GLP1R and the glucagon receptor (GCGR) can improve glucose metabolism and provide superior weight loss when compared to selective GLP1R agonism in preclinical species. This paper will highlight chemistry structure-activity relationship optimization and summarize in vivo efficacy studies toward the discovery of a once daily balanced dual agonist 12 (MK-1462), which was advanced into clinical trials.

Cochlear implantation after deafness from Pasteurella multocida meningitis.

A woman in her late 40s who works as a veterinary technician represented to the emergency department with increasing headache, confusion, neck stiffness, subjective fevers and distorted hearing 2 days after diagnosis of viral infection at an outside emergency department.Diagnosis of Pasteurella multocida was made from blood cultures and lumbar puncture. Intravenous ceftriaxone was administered for 21 days. By the time of resolution of acute meningitis, she had become completely deaf bilaterally. MRI revealed faint early ossification/possible labyrinthitis ossificans of the basal cochlea, which was confirmed on surgical exploration during the placement of cochlear implants bilaterally 42 days later. We discuss how the atypical features of this infection lead to diagnostic delay and high morbidity, the unique imaging/surgical findings resulting from the infection, and the clinical utility of early and bilateral cochlear implantation in this and similar cases.

Predicting Schwannoma Growth in a Tumor Model Using Targeted Imaging.

INTRODUCTION: Vestibular schwannoma (VS) is a common pathology encountered in neurotology clinics. Many patients are observed with a "wait and scan" approach. Previous efforts to determine radiographic indicators of future growth have been unsuccessful. Using a mouse subcutaneous tumor model, we seek to determine if fluorescent imaging with directed immunotargets could be used to predict schwannoma growth rate. METHODS: Anti-VEGFR2 and anti-Her2/Neu monoclonal antibodies were covalently linked to a near-infrared probe (IRDye800). Immunodeficient mice underwent subcutaneous injections with a rat-derived schwann (R3) cell line. When tumor growth was evident, either Anti-VEGFR2-IRDye800, anti-Her2/Neu-IRDye800, or Immunoglobulin G (IgG) Isotype-IRDye800 (control) were injected via tail vein. The mice were serially imaged in a closed field near-IR device. Fluorescent data were analyzed for tumor signal and correlated with tumor sie and growth rate. Heterogeneity of fluorescent tumor signal was also assessed. RESULTS: In both anti-VEGFR2 and anti-Her2/Neu groups, there were strong correlations between day 1 mean tumor fluorescence and eventual maximum tumor volume (p = 0.002, 0.001; r2 = 0.92, 0.86). There was also strong correlation with maximum tumor signal on day 1 and maximum tumor volume (p = 0.003, 0.008; r2 = 0.90, 0.91). There was no such correlation in the control group (p = 0.99, 0.75; r2 = 0.0002, 0.028). CONCLUSION: Given the potential morbidity in VS intervention, observation is an appropriate approach for patients with slow-growing or stagnant tumors. We seek to identify immunotargets in a murine model that show promise in predicting schwannoma growth with advanced imaging techniques. Both Her2/Neu and VEGFR2 correlated strongly wth tumor size and growth rates and are promising targets that merit further investigation.

Current management of superior semicircular canal dehiscence syndrome.

PURPOSE OF REVIEW: The current article reviews literature on the contemporary management of superior semicircular canal dehiscence syndrome (SSCDS). Approaches to management and surgical techniques are compared along with a discussion of the use of more standardized, objective outcome measures. RECENT FINDINGS: Considerable debate still exists as to what approach and technique is most appropriate for patients with SSCDS and how to best measure postoperative outcomes. However, it is increasingly accepted that multiple factors account for outcomes in SSCDS, including presenting symptoms and presence of vestibular comorbidities. Therefore, surgical intervention is best tailored to each individual patient. Data on SSCDS outcomes is heterogenous, and increased emphasis is being placed on validated measures of outcome. Round window approaches remain controversial and their role is still undefined. SUMMARY: The treatment strategies for SSCDS continue to diversify. A patient-specific approach with systematic documentation of outcomes will continue to inform how these patients are best managed.

Perioperative Pain Management Following Otologic Surgery.

Otologic surgery involves a broad range of procedures. In general, postoperative pain from most otologic surgeries can be managed with little to no opioids, and surgeons should make a concerted effort to minimize narcotic prescriptions in the midst of the opioid crisis. Many procedures, including transcanal surgeries and even postauricular surgeries, may performed with local anesthetic in selected patients. Multimodal pain regimens, local anesthesia, and alternative approaches have shown promise in minimizing narcotic use, and should be considered. Preoperative counseling to appropriately manage expectations and goals is imperative for patient satisfaction and safety.

Current management of congenital anterior cranial base encephaloceles.

OBJECTIVES: Congenital encephaloceles provide unique diagnostic and reconstructive challenges for the pediatric rhinologist. The objectives of the current study were to evaluate contemporary treatment strategies for congenital encephaloceles focusing on presentation, surgical technique, and outcomes. METHODS: Multi-institutional retrospective chart review of congenital encephaloceles (2003-2019). Data regarding demographics, presenting symptoms, associated abnormalities, surgical technique, size, location, and complications were collected. RESULTS: Fourteen patients with 15 congenital encephaloceles were treated using endoscopic techniques (avg 6.0 years, range 2 months-22 years) with mean follow up of 23 months. The majority presented with nasal obstruction (n = 13); only one child had cerebrospinal fluid (CSF) rhinorrhea. Associated anomalies included nasal deformities, congenital hypopituitarism, and Morning Glory syndrome. Average encephalocele size was 2.44 cm (range 0.5-3.6 cm) with mean skull base defect size of 8.6 x 7.7 mm. Locations included the foramen cecum (n = 9), central sphenoid (n = 3), midline anterior cranial fossa (n = 1), orbital plate of frontal bone (n = 1), and ethmoid roof (n = 1). Because of favorable expansion from encephaloceles, it was unnecessary to postpone surgeries to allow nasal cavity growth. Three individuals had prior operations, including surgeries for "nasal polyp" or "adenoid cyst". Two patients had post-operative complications (meningitis and CSF leak) effectively treated with no further sequelae. CONCLUSIONS: In the current study, congenital encephaloceles in children as young as 2 months were successfully repaired using endoscopic techniques. Endoscopic approaches remain a safe and effective intervention for management of these lesions.

Pembrolizumab microgravity crystallization experimentation.

Crystallization processes have been widely used in the pharmaceutical industry for the manufacture, storage, and delivery of small-molecule and small protein therapeutics. However, the identification of crystallization processes for biologics, particularly monoclonal antibodies, has been prohibitive due to the size and the flexibility of their overall structure. There remains a challenge and an opportunity to utilize the benefits of crystallization of biologics. The research laboratories of Merck Sharp & Dome Corp. (MSD) in collaboration with the International Space Station (ISS) National Laboratory performed crystallization experiments with pembrolizumab (Keytruda®) on the SpaceX-Commercial Resupply Services-10 mission to the ISS. By leveraging microgravity effects such as reduced sedimentation and minimal convection currents, conditions producing crystalline suspensions of homogeneous monomodal particle size distribution (39 µm) in high yield were identified. In contrast, the control ground experiments produced crystalline suspensions with a heterogeneous bimodal distribution of 13 and 102 µm particles. In addition, the flight crystalline suspensions were less viscous and sedimented more uniformly than the comparable ground-based crystalline suspensions. These results have been applied to the production of crystalline suspensions on earth, using rotational mixers to reduce sedimentation and temperature gradients to induce and control crystallization. Using these techniques, we have been able to produce uniform crystalline suspensions (1-5 µm) with acceptable viscosity (<12 cP), rheological, and syringeability properties suitable for the preparation of an injectable formulation. The results of these studies may help widen the drug delivery options to improve the safety, adherence, and quality of life for patients and caregivers.

Fluorescence Imaging of Nerves During Surgery.

OBJECTIVE: This review details the agents for fluorescence-guided nerve imaging in both preclinical and clinical use to identify factors important in selecting nerve-specific fluorescent agents for surgical procedures. BACKGROUND: Iatrogenic nerve injury remains a significant cause of morbidity in patients undergoing surgical procedures. Current real-time identification of nerves during surgery involves neurophysiologic nerve stimulation, which has practical limitations. Intraoperative fluorescence-guided imaging provides a complimentary means of differentiating tissue types and pathology. Recent advances in fluorescence-guided nerve imaging have shown promise, but the ideal agent remains elusive. METHODS: In February 2018, PubMed was searched for articles investigating peripheral nerve fluorescence. Key terms used in this search include: "intraoperative, nerve, fluorescence, peripheral nerve, visualization, near infrared, and myelin." Limits were set to exclude articles exclusively dealing with central nervous system targets or written in languages other than English. References were cross-checked for articles not otherwise identified. RESULTS: Of the nonspecific agents, tracers that rely on axonal transport showed the greatest tissue specificity; however, neurovascular dyes already enjoy wide clinical use. Fluorophores specific to nerve moieties result in excellent nerve to background ratios. Although noteworthy findings on tissue specificity, toxicity, and route of administration specific to each fluorescent agent were reported, significant data objectively quantifying nerve-specific fluorescence and toxicity are lacking. CONCLUSIONS: Fluorescence-based nerve enhancement has advanced rapidly over the past 10 years with potential for continued utilization and progression in translational research. An ideal agent would be easily administered perioperatively, would not cross the blood-brain barrier, and would fluoresce in the near-infrared spectrum. Agents administered systemically that target nerve-specific moieties have shown the greatest promise. Based on the heterogeneity of published studies and methods for reporting outcomes, it appears that the development of an optimal nerve imaging agent remains challenging.

Evolving Trends in Cochlear Implantation: A Critical Look at the Older Population.

OBJECTIVES/HYPOTHESIS: Cochlear implantation (CI) is a well-accepted surgical option for the treatment of moderate to profound deafness. The purpose of this study was to evaluate the temporal and geographic trends of this procedure nationwide in the Medicare population in an attempt to explore the impact of evolving technologies and changes in healthcare policy. METHODS: Medicare Part B national summary procedural datasets from 2007 to 2016 were obtained. Current Procedural Terminology codes for CI as well as auditory osseointegrated implantation were obtained. Centers for Medicare and Medicaid Services (CMS) datasets were evaluated to determine temporal trends. For geographic trends, specific carrier datasets from 2007 and 2016 were used. RESULTS: From 2007 through 2016, the number of CI procedures increased annually from 1603 to 3600 (124.6%). Other procedures to treat hearing loss including bone-anchored implantation exhibited comparatively modest increases (23%, 90%). CI procedures increased every year in contrast to bone-anchored implants. Controlling for Medicare population, the greatest number of CI procedures performed per capita in the United States was in the West North Central, with an average 1.05 CIs per 10,000 beneficiaries. CONCLUSION: The number of CI procedures performed in the elderly population has increased markedly over the past 10 years, far outpacing growth in other hearing surgeries. Potential reasons may relate to changes in criteria for CI candidacy over the past decade, although significant regional variability demonstrated suggests a lack of consensus. Further studies would be necessary to ascertain the true reason for geographic disparities.

Evaluation of optical imaging agents in a fluorescence-guided surgical model of head and neck cancer.

BACKGROUND: Tumor proliferation often occurs from pathologic receptor upregulation. These receptors provide unique targets for near-infrared (NIR) probes that have fluorescence-guided surgery (FGS) applications. We demonstrate the use of three smart-targeted probes in a model of head and neck squamous cell carcinoma. METHODS: A dose escalation study was performed using IntegriSense750, ProSense750EX, and ProSense750FAST in mice (n = 5) bearing luciferase-positive SCC-1 flank xenograft tumors. Whole body fluorescence imaging was performed serially after intravenous injection using commercially available open-field (LUNA, Novadaq, Canada) and closed-field NIR systems (Pearl, LI-COR, Lincoln, NE). An ex vivo, whole-body biodistribution was conducted. Lastly, FGS was performed with IntegriSense750 to demonstrate orthotopic and metastatic disease localization. RESULTS: Disease fluorescence delineation was assessed by tumor-to-background fluorescence ratios (TBR). Peak TBR values were 3.3 for 1 nmol ProSense750EX, 5.5 for 6 nmol ProSense750FAST, and 10.8 for 4 nmol IntegriSense750 at 5.5, 3, and 4 d post administration, respectively. Agent utility is unique: ProSense750FAST provides sufficient contrast quickly (TBR: 1.5, 3 h) while IntegriSense750 produces strong (TBR: 10.8) contrast with extended administration-to-resection time (96 h). IntegriSense750 correctly identified all diseased nodes in situ during exploratory surgeries. Ex vivo, whole-body biodistribution was assessed by tumor-to-tissue fluorescence ratios (TTR). Agents provided sufficient fluorescence contrast to discriminate disease from background, TTR>1. IntegriSense750 was most robust in neural tissue (TTR: 64) while ProSense750EX was superior localizing disease against lung tissue (TBR: 13). CONCLUSION: All three agents appear effective for FGS.

Can We Make Small Molecules Lean? Optimization of a Highly Lipophilic TarO Inhibitor.

We describe our optimization efforts to improve the physicochemical properties, solubility, and off-target profile of 1, an inhibitor of TarO, an early stage enzyme in the biosynthetic pathway for wall teichoic acid (WTA) synthesis. Compound 1 displayed a TarO IC50 of 125 nM in an enzyme assay and possessed very high lipophilicity (clogP = 7.1) with no measurable solubility in PBS buffer. Structure-activity relationship (SAR) studies resulted in a series of compounds with improved lipophilic ligand efficiency (LLE) consistent with the reduction of clogP. From these efforts, analog 9 was selected for our initial in vivo study, which in combination with subefficacious dose of imipenem (IPM) robustly lowered the bacterial burden in a neutropenic Staphylococci murine infection model. Concurrent with our in vivo optimization effort using 9, we further improved LLE as exemplified by a much more druglike analog 26.

Development of a Convenient In Vitro Gel Diffusion Model for Predicting the In Vivo Performance of Subcutaneous Parenteral Formulations of Large and Small Molecules.

Parenteral delivery remains a compelling drug delivery route for both large- and small-molecule drugs and can bypass issues encountered with oral absorption. For injectable drug products, there is a strong patient preference for subcutaneous administration due to its convenience over intravenous infusion. However, in subcutaneous injection, in contrast to intravenous administration, the formulation is in contact with an extracellular matrix environment that behaves more like a gel than a fluid. This can impact the expected performance of a formulation. Since typical bulk fluid dissolution studies do not accurately simulate the subcutaneous environment, improved in vitro models to help better predict the behavior of the formulation are critical. Herein, we detail the development of a new model system consisting of a more physiologically relevant gel phase to simulate the rate of drug release and diffusion from a subcutaneous injection site using agarose hydrogels as a tissue mimic. This is coupled with continuous real-time data collection to accurately monitor drug diffusion. We show how this in vitro model can be used as an in vivo performance differentiator for different formulations of both large and small molecules. Thus, this model system can be used to improve optimization and understanding of new parenteral drug formulations in a rapid and convenient manner.

Characterizing the Utility and Limitations of Repurposing an Open-Field Optical Imaging Device for Fluorescence-Guided Surgery in Head and Neck Cancer Patients.

The purpose of this study was to assess the potential of U.S. Food and Drug Administration-cleared devices designed for indocyanine green-based perfusion imaging to identify cancer-specific bioconjugates with overlapping excitation and emission wavelengths. Recent clinical trials have demonstrated potential for fluorescence-guided surgery, but the time and cost of the approval process may impede clinical translation. To expedite this translation, we explored the feasibility of repurposing existing optical imaging devices for fluorescence-guided surgery. METHODS: Consenting patients (n = 15) scheduled for curative resection were enrolled in a clinical trial evaluating the safety and specificity of cetuximab-IRDye800 (NCT01987375). Open-field fluorescence imaging was performed preoperatively and during the surgical resection. Fluorescence intensity was quantified using integrated instrument software, and the tumor-to-background ratio characterized fluorescence contrast. RESULTS: In the preoperative clinic, the open-field device demonstrated potential to guide preoperative mapping of tumor borders, optimize the day of surgery, and identify occult lesions. Intraoperatively, the device demonstrated robust potential to guide surgical resections, as all peak tumor-to-background ratios were greater than 2 (range, 2.2-14.1). Postresection wound bed fluorescence was significantly less than preresection tumor fluorescence (P < 0.001). The repurposed device also successfully identified positive margins. CONCLUSION: The open-field imaging device was successfully repurposed to distinguish cancer from normal tissue in the preoperative clinic and throughout surgical resection. This study illuminated the potential for existing open-field optical imaging devices with overlapping excitation and emission spectra to be used for fluorescence-guided surgery.