Enhanced quantitation of pathological α-synuclein in patient biospecimens by RT-QuIC seed amplification assays.

Disease associated pathological aggregates of alpha-synuclein (αSynD) exhibit prion-like spreading in synucleinopathies such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Seed amplification assays (SAAs) such as real-time quaking-induced conversion (RT-QuIC) have shown high diagnostic sensitivity and specificity for detecting proteopathic αSynD seeds in a variety of biospecimens from PD and DLB patients. However, the extent to which relative proteopathic seed concentrations are useful as indices of a patient's disease stage or prognosis remains unresolved. One feature of current SAAs that complicates attempts to correlate SAA results with patients' clinical and other laboratory findings is their quantitative imprecision, which has typically been limited to discriminating large differences (e.g. 5-10 fold) in seed concentration. We used end-point dilution (ED) RT-QuIC assays to determine αSynD seed concentrations in patient biospecimens and tested the influence of various assay variables such as serial dilution factor, replicate number and data processing methods. The use of 2-fold versus 10-fold dilution factors and 12 versus 4 replicate reactions per dilution reduced ED-RT-QuIC assay error by as much as 70%. This enhanced assay format discriminated as little as 2-fold differences in αSynD seed concentration besides detecting ~2-16-fold seed reductions caused by inactivation treatments. In some scenarios, analysis of the data using Poisson and midSIN algorithms provided more consistent and statistically significant discrimination of different seed concentrations. We applied our improved assay strategies to multiple diagnostically relevant PD and DLB antemortem patient biospecimens, including cerebrospinal fluid, skin, and brushings of the olfactory mucosa. Using ED αSyn RT-QuIC as a model SAA, we show how to markedly improve the inter-assay reproducibility and quantitative accuracy. Enhanced quantitative SAA accuracy should facilitate assessments of pathological seeding activities as biomarkers in proteinopathy diagnostics and prognostics, as well as in patient cohort selection and assessments of pharmacodynamics and target engagement in drug trials.

Implementation of Artificial Intelligence-Based Diabetic Retinopathy Screening in a Tertiary Care Hospital in Quebec: Prospective Validation Study.

BACKGROUND: Diabetic retinopathy (DR) affects about 25% of people with diabetes in Canada. Early detection of DR is essential for preventing vision loss. OBJECTIVE: We evaluated the real-world performance of an artificial intelligence (AI) system that analyzes fundus images for DR screening in a Quebec tertiary care center. METHODS: We prospectively recruited adult patients with diabetes at the Centre hospitalier de l'Université de Montréal (CHUM) in Montreal, Quebec, Canada. Patients underwent dual-pathway screening: first by the Computer Assisted Retinal Analysis (CARA) AI system (index test), then by standard ophthalmological examination (reference standard). We measured the AI system's sensitivity and specificity for detecting referable disease at the patient level, along with its performance for detecting any retinopathy and diabetic macular edema (DME) at the eye level, and potential cost savings. RESULTS: This study included 115 patients. CARA demonstrated a sensitivity of 87.5% (95% CI 71.9-95.0) and specificity of 66.2% (95% CI 54.3-76.3) for detecting referable disease at the patient level. For any retinopathy detection at the eye level, CARA showed 88.2% sensitivity (95% CI 76.6-94.5) and 71.4% specificity (95% CI 63.7-78.1). For DME detection, CARA had 100% sensitivity (95% CI 64.6-100) and 81.9% specificity (95% CI 75.6-86.8). Potential yearly savings from implementing CARA at the CHUM were estimated at CAD $245,635 (US $177,643.23, as of July 26, 2024) considering 5000 patients with diabetes. CONCLUSIONS: Our study indicates that integrating a semiautomated AI system for DR screening demonstrates high sensitivity for detecting referable disease in a real-world setting. This system has the potential to improve screening efficiency and reduce costs at the CHUM, but more work is needed to validate it.

Practical parameter identifiability and handling of censored data with Bayesian inference in mathematical tumour models.

Mechanistic mathematical models (MMs) are a powerful tool to help us understand and predict the dynamics of tumour growth under various conditions. In this work, we use 5 MMs with an increasing number of parameters to explore how certain (often overlooked) decisions in estimating parameters from data of experimental tumour growth affect the outcome of the analysis. In particular, we propose a framework for including tumour volume measurements that fall outside the upper and lower limits of detection, which are normally discarded. We demonstrate how excluding censored data results in an overestimation of the initial tumour volume and the MM-predicted tumour volumes prior to the first measurements, and an underestimation of the carrying capacity and the MM-predicted tumour volumes beyond the latest measurable time points. We show in which way the choice of prior for the MM parameters can impact the posterior distributions, and illustrate that reporting the most likely parameters and their 95% credible interval can lead to confusing or misleading interpretations. We hope this work will encourage others to carefully consider choices made in parameter estimation and to adopt the approaches we put forward herein.

Apolipoprotein A1 and high-density lipoprotein limit low-density lipoprotein transcytosis by binding SR-B1.

Atherosclerosis results from the deposition and oxidation of LDL and immune cell infiltration in the sub-arterial space leading to arterial occlusion. Studies have shown that transcytosis transports circulating LDL across endothelial cells lining blood vessels. LDL transcytosis is initiated by binding to either scavenger receptor B1 (SR-B1) or activin A receptor-like kinase 1 on the apical side of endothelial cells leading to its transit and release on the basolateral side. HDL is thought to partly protect individuals from atherosclerosis due to its ability to remove excess cholesterol and act as an antioxidant. Apolipoprotein A1 (APOA1), an HDL constituent, can bind to SR-B1, raising the possibility that APOA1/HDL can compete with LDL for SR-B1 binding, thereby limiting LDL deposition in the sub-arterial space. To examine this possibility, we used in vitro approaches to quantify the internalization and transcytosis of fluorescent LDL in coronary endothelial cells. Using microscale thermophoresis and affinity capture, we find that SR-B1 and APOA1 interact and that binding is enhanced when using the cardioprotective variant of APOA1 termed Milano (APOA1-Milano). In male mice, transiently increasing the levels of HDL reduced the acute deposition of fluorescently labeled LDL in the atheroprone inner curvature of the aorta. Reduced LDL deposition was also observed when increasing circulating wild-type APOA1 or the APOA1-Milano variant, with a more robust inhibition from the APOA1-Milano. The results suggest that HDL may limit SR-B1-mediated LDL transcytosis and deposition, adding to the mechanisms by which it can act as an atheroprotective particle.

Evaluating the economic burden of acute myeloid leukemia in Canada.

Background Acute myeloid leukemia (AML) represents a significant burden for patients and their families, and to the healthcare system. This study estimated the total cost of illness associated with newly diagnosed AML patients in Canada. Methods The economic burden of AML was estimated using an incidence-based model, analyzing different types of AML cases in Canada. Direct and indirect costs were calculated using scientific literature and Canadian clinical experts' inputs. Patients were categorized depending on their eligibility for intensive chemotherapy (fit and unfit patients) as well as according to age and cytogenetic markers. Results The total average cost of AML per patient is estimated to be $178,073 with a cost of $210,983 and $145,163 for fit and unfit patients, respectively. The costs related to treatment represent half of the total average cost (52%), followed by hematopoietic stem cell transplant (23%), best supportive care (16%), productivity loss (6%) and wastage (4%) Conclusions For patients with AML, the costs associated with fit patients are higher than unfit patients. Hospitalization and best supportive care costs are key cost drivers for the total costs of fit and unfit patients, respectively. This study highlights that AML is associated with a significant economic burden in Canada.

Exploring associations between viral titer measurements and disease outcomes in ferrets inoculated with 125 contemporary influenza A viruses.

As use of the ferret model to study influenza A virus (IAV) pathogenicity increases, periodic assessment of data generated in this model is warranted, to identify features associated with virus replication throughout the respiratory tract and to refine future analyses. However, protocol-specific differences present between independent laboratories limit easy aggregation of virological data. We compiled viral titer and clinical data from >1,000 ferrets inoculated with 125 contemporary IAV under a consistent experimental protocol (including high- and low-pathogenicity avian, swine-origin, and human viruses, spanning H1, H2, H3, H5, H7, and H9 subtypes) and examined which meaningful and statistically supported associations were present among numerous quantitative measurements. Viral titers correlated positively between ferret nasal turbinate tissue, lung tissue, and nasal wash specimens, though the strength of the associations varied, notably regarding the particular nasal wash summary measure employed and properties of the virus itself. Use of correlation coefficients and mediation analyses further supported the interconnectedness of viral titer measurements taken at different sites throughout the respiratory tract. IAV possessing mammalian host adaptation markers in the HA and PB2 exhibited more rapid growth in the ferret upper respiratory tract early after infection, supported by quantities derived from infectious titer data to capture infection progression, compared with viruses bearing hallmarks of avian IAV. Collectively, this work identifies summary metrics most closely linked with virological and phenotypic outcomes in ferrets, supporting continued refinement of data analyzed from in vivo experimentation, notably from studies conducted to evaluate the public health risk posed by novel and emerging IAV.IMPORTANCEFerrets are frequently employed to study the pandemic potential of novel and emerging influenza A viruses. However, systematic retrospective analyses of data generated from these experiments are rarely performed, limiting our ability to identify trends in this data and explore how analyses can be refined. Using logarithmic viral titer and clinical data aggregated from one research group over 20 years, we assessed which meaningful and statistically supported associations were present among numerous quantitative measurements obtained from influenza A virus (IAV)-infected ferrets, including those capturing viral titers, infection progression, and disease severity. We identified numerous linear correlations between parameters assessing virus replication at discrete sites in vivo, including parameters capturing infection progression not frequently employed in the field, and sought to investigate the interconnected nature of these associations. This work supports continued refinement of data analyzed from in vivo experimentation, notably from studies which evaluate the public health risk posed by IAV.

The effect of random virus failure following cell entry on infection outcome and the success of antiviral therapy.

A virus infection can be initiated with very few or even a single infectious virion, and as such can become extinct, i.e. stochastically fail to take hold or spread significantly. There are many ways that a fully competent infectious virion, having successfully entered a cell, can fail to cause a productive infection, i.e. one that yields infectious virus progeny. Though many stochastic models (SMs) have been developed and used to estimate a virus infection's establishment probability, these typically neglect infection failure post virus entry. The SM presented herein introduces parameter [Formula: see text] which corresponds to the probability that a virion's entry into a cell will result in a productive cell infection. We derive an expression for the likelihood of infection establishment in this new SM, and find that prophylactic therapy with an antiviral reducing [Formula: see text] is at least as good or better at decreasing the establishment probability, compared to antivirals reducing the rates of virus production or virus entry into cells, irrespective of the SM parameters. We investigate the difference in the fraction of cells consumed by so-called extinct versus established virus infections, and find that this distinction becomes biologically meaningless as the probability of establishment approaches zero. We explain why the release of virions continuously over an infectious cell's lifespan, rather than as a single burst at the end of the cell's lifespan, does not result in an increased risk of infection extinction. We show, instead, that the number of virus released, not the timing of the release, affects infection establishment and associated critical antiviral efficacy.

Efficacy, tolerability, and endometrial safety of ospemifene compared with current therapies for the treatment of vulvovaginal atrophy: a systematic literature review and network meta-analysis.

IMPORTANCE: Ospemifene is a novel selective estrogen receptor modulator developed for the treatment of moderate to severe postmenopausal vulvovaginal atrophy (VVA). OBJECTIVE: The aim of the study is to perform a systematic literature review (SLR) and network meta-analysis (NMA) to assess the efficacy and safety of ospemifene compared with other therapies used in the treatment of VVA in North America and Europe. EVIDENCE REVIEW: Electronic database searches were conducted in November 2021 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized or nonrandomized controlled trials targeting postmenopausal women with moderate to severe dyspareunia and/or vaginal dryness and involving ospemifene or at least one VVA local treatment were considered. Efficacy data included changes from baseline in superficial and parabasal cells, vaginal pH, and the most bothersome symptom of vaginal dryness or dyspareunia, as required for regulatory approval. Endometrial outcomes were endometrial thickness and histologic classifications, including endometrial polyp, hyperplasia, and cancer. For efficacy and safety outcomes, a Bayesian NMA was performed. Endometrial outcomes were compared in descriptive analyses. FINDINGS: A total of 44 controlled trials met the eligibility criteria ( N = 12,637 participants). Network meta-analysis results showed that ospemifene was not statistically different from other active therapies in most efficacy and safety results. For all treatments, including ospemifene, the posttreatment endometrial thickness values (up to 52 wk of treatment) were under the recognized clinical threshold value of 4 mm for significant risk of endometrial pathology. Specifically, for women treated with ospemifene, endometrial thickness ranged between 2.1 and 2.3 mm at baseline and 2.5 and 3.2 mm after treatment. No cases of endometrial carcinoma or hyperplasia were observed in ospemifene trials, nor polyps with atypical hyperplasia or cancer after up to 52 weeks of treatment. CONCLUSIONS AND RELEVANCE: Ospemifene is an efficacious, well-tolerated, and safe therapeutic option for postmenopausal women with moderate to severe symptoms of VVA. Efficacy and safety outcomes with ospemifene are similar to other VVA therapies in North America and Europe.

Utility of Human In Vitro Data in Risk Assessments of Influenza A Virus Using the Ferret Model.

As influenza A viruses (IAV) continue to cross species barriers and cause human infection, the establishment of risk assessment rubrics has improved pandemic preparedness efforts. In vivo pathogenicity and transmissibility evaluations in the ferret model represent a critical component of this work. As the relative contribution of in vitro experimentation to these rubrics has not been closely examined, we sought to evaluate to what extent viral titer measurements over the course of in vitro infections are predictive or correlates of nasal wash and tissue measurements for IAV infections in vivo. We compiled data from ferrets inoculated with an extensive panel of over 50 human and zoonotic IAV (inclusive of swine-origin and high- and low-pathogenicity avian influenza viruses associated with human infection) under a consistent protocol, with all viruses concurrently tested in a human bronchial epithelial cell line (Calu-3). Viral titers in ferret nasal wash specimens and nasal turbinate tissue correlated positively with peak titer in Calu-3 cells, whereas additional phenotypic and molecular determinants of influenza virus virulence and transmissibility in ferrets varied in their association with in vitro viral titer measurements. Mathematical modeling was used to estimate more generalizable key replication kinetic parameters from raw in vitro viral titers, revealing commonalities between viral infection progression in vivo and in vitro. Meta-analyses inclusive of IAV that display a diverse range of phenotypes in ferrets, interpreted with mathematical modeling of viral kinetic parameters, can provide critical information supporting a more rigorous and appropriate contextualization of in vitro experiments toward pandemic preparedness. IMPORTANCE Both in vitro and in vivo models are employed for assessing the pandemic potential of novel and emerging influenza A viruses in laboratory settings, but systematic examinations of how well viral titer measurements obtained in vitro align with results from in vivo experimentation are not frequently performed. We show that certain viral titer measurements following infection of a human bronchial epithelial cell line are positively correlated with viral titers in specimens collected from virus-inoculated ferrets and employ mathematical modeling to identify commonalities between viral infection progression between both models. These analyses provide a necessary first step in enhanced interpretation and incorporation of in vitro-derived data in risk assessment activities and highlight the utility of employing mathematical modeling approaches to more closely examine features of virus replication not identifiable by experimental studies alone.

Correction: Time to revisit the endpoint dilution assay and to replace the TCID50 as a measure of a virus sample's infection concentration.

[This corrects the article DOI: 10.1371/journal.pcbi.1009480.].

Correction: A mathematical model describing the localization and spread of influenza A virus infection within the human respiratory tract.

[This corrects the article DOI: 10.1371/journal.pcbi.1007705.].

Short-term efficacy of latanoprostene bunod for the treatment of open-angle glaucoma and ocular hypertension: a systematic literature review and a network meta-analysis.

BACKGROUND/AIMS: To assess the comparative efficacy of latanoprostene bunod (LBN), a novel prostaglandin analogue (PGA), to other medications for open-angle glaucoma and ocular hypertension on lowering intraocular pressure (IOP). METHODS: A systematic literature review adapted from the Li et al (Ophthalmology, 2016) study was conducted. Medline, Embase and PubMed were searched for randomised controlled trials published between 1 January 2014 and 19 March 2020. Studies had to report IOP reduction after 3 months for at least two different treatments among placebo, PGAs (bimatoprost 0.01%, bimatoprost 0.03%, latanoprost, LBN, tafluprost, unoprostone) or apraclonidine, betaxolol, brimonidine, brinzolamide, carteolol, dorzolamide, levobunolol, timolol, travoprost. A Bayesian network meta-analysis was performed to provide the relative effect in terms of mean difference (95% credible interval) of IOP reduction and ranking probabilities. Surface under the cumulative ranking curve (SUCRA) was generated. RESULTS: A total of 106 trials were included with data for 18 523 participants. LBN was significantly more effective than unoprostone (-3.45 (-4.77 to -2.12)). Although relative effect was not significative, compared with other PGAs, LBN numerically outperformed latanoprost (-0.70 (-1.83 to 0.43)) and tafluoprost (-0.41 (-1.87 to 1.07)), was similar to bimatoprost 0.01% (-0.02(-1.59 to 1.55)) and was slightly disadvantaged by bimatoprost 0.03% (-0.17 (-1.42 to 1.07)). LBN was significantly more efficient than the beta-blockers apraclonidine, betaxolol, brimonidine, brinzolamide, carteolol, dorzolamide and timolol. According to SUCRA, LBN was ranked second after bimatoprost 0.03%, followed by bimatoprost 0.01%. CONCLUSION: LBN was significantly more effective than the PGA unoprostone and most of the beta-blockers. Compared with the most widely used PGAs, LBN numerically outperformed latanoprost and travoprost and was similar to bimatoprost 0.01%.

The Economic Impact of Originator-to-Biosimilar Non-medical Switching in the Real-World Setting: A Systematic Literature Review.

INTRODUCTION: To save costs to the healthcare system, forced non-medical switch (NMS) policies that cut drug coverage for originator biologics and fund only less expensive biosimilars are being implemented. However, costs related to the impact of NMS on healthcare resource utilization (HCRU) must also be considered. This study aims to summarize the evidence on the economic impact of an originator-to-biosimilar NMS. METHODS: A systematic literature review (SLR) was conducted. Publications reporting on HCRU or costs associated with originator-to-biosimilar NMS in the real-world setting were searched in MEDLINE and EMBASE from January 2008 to February 2020. In addition to hand searching the reference lists of relevant publications and SLRs, key conference websites, PubMed, and various government sites were also searched for the 2 years preceding the search (2018-2020). RESULTS: A total of 1845 citations were identified, of which 49 were retained for data extraction. Most studies reporting on the HCRU associated with NMS reported on post-NMS HCRU alone without a comparison pre-NMS. However, four studies described a difference in HCRU (i.e., investigations pre- vs post-switch or between non-switchers vs switchers), all of which reported a relative increase in HCRU, including laboratory testing, imaging, medical visits, and hospitalizations, amongst patients who underwent an originator-to-biosimilar NMS. Most studies reporting on the costs associated with NMS reported significant savings following NMS on the basis of drug costs alone. However, four studies specifically reporting on the difference of costs following originator-to-biosimilar NMS all demonstrated an increase in HCRU-related costs associated with NMS (increase in HCRU-related costs of 4-37% or 148-2234 2020 Canadian dollars). CONCLUSION: Amongst the studies that reported on the difference in HCRU pre- vs post-switch or between non-switchers and switchers, all showed an increase in HCRU and related costs associated with NMS, suggesting that the expected overall savings due to less costly drug prices may be reduced as a result of an increase in HCRU and its associated costs post-switch. Nevertheless, more real-world studies that include NMS-related healthcare costs in addition to drug costs are needed.

Time to revisit the endpoint dilution assay and to replace the TCID50 as a measure of a virus sample's infection concentration.

The endpoint dilution assay's output, the 50% infectious dose (ID50), is calculated using the Reed-Muench or Spearman-Kärber mathematical approximations, which are biased and often miscalculated. We introduce a replacement for the ID50 that we call Specific INfection (SIN) along with a free and open-source web-application, midSIN (https://midsin.physics.ryerson.ca) to calculate it. midSIN computes a virus sample's SIN concentration using Bayesian inference based on the results of a standard endpoint dilution assay, and requires no changes to current experimental protocols. We analyzed influenza and respiratory syncytial virus samples using midSIN and demonstrated that the SIN/mL reliably corresponds to the number of infections a sample will cause per mL. It can therefore be used directly to achieve a desired multiplicity of infection, similarly to how plaque or focus forming units (PFU, FFU) are used. midSIN's estimates are shown to be more accurate and robust than the Reed-Muench and Spearman-Kärber approximations. The impact of endpoint dilution plate design choices (dilution factor, replicates per dilution) on measurement accuracy is also explored. The simplicity of SIN as a measure and the greater accuracy provided by midSIN make them an easy and superior replacement for the TCID50 and other in vitro culture ID50 measures. We hope to see their universal adoption to measure the infectivity of virus samples.

Impact of Oral Targeted Therapy on the Economic Burden of Chronic Lymphocytic Leukemia in Canada.

Background: Continuous oral targeted therapy (OTT) for chronic lymphocytic leukemia (CLL) represents an effective therapy but also a major economic burden on the healthcare system. This study aimed to estimate future direct costs, along with the prevalence, of CLL in the era of continuous OTT in Canada. Methods: The economic burden of OTT was modelled and compared to chemoimmunotherapy (CIT), for CLL treatment. The burden was assessed/projected from 2011 to 2025. For the OTT scenario, CIT was considered the standard of care before 2015, while OTT was considered standard of care for patients with either unmutated immunoglobulin heavy-chain variable (IGHV) or del(17p)/TP53 mutations starting in 2015 and, from 2020 onwards, for all first-line treatments except for patients with mutated IGHV. A Markov model was developed including four health states: watchful-waiting, first-line treatment, relapse and death. Costs of therapy, follow-up/monitoring and adverse events were included. Key clinical parameters were extracted from pivotal clinical trials. Results: As incidence rates and rate of survival are increasing, the prevalence of CLL in Canada is projected to increase 1.8-fold, from 8301 patients in 2011 to 14,654 by 2025. Correspondingly, the total annual costs of CLL management are predicted to increase 15.7-fold, from $60.8 million to $957.5 million during that same period. Conclusions: Although OTT enhances survival for patients with CLL, it is nonetheless associated with an important economic burden due to the projected vast increase in costs from 2011 to 2025. Changes in clinical strategies, such as implementation of a fixed OTT treatment duration, could help alleviate financial burden.

Economic Evaluation of a New Polygenic Risk Score to Predict Nephropathy in Adult Patients With Type 2 Diabetes.

OBJECTIVES: The current screening method for diabetic nephropathy (DN) is based on detection of albumin in the urine and decline of glomerular filtration rate. The latter usually occurs relatively late in the course of the disease. A polygenic risk score (PRS) was recently developed for early prediction of the risk for patients with type 2 diabetes (T2D) to develop DN. The aim of this study was to assess the economic impact of the implementation of the PRS for early prediction of DN in patients with T2D compared with usual screening methods in Canada. METHODS: A cost-utility analysis was developed using a Markov model. Health states include pre-end-stage renal disease (ESRD), ESRD and death. Model efficacy parameters were based on prediction of outcome data by polygenic risk testing of the genotyped participants in the Action in Diabetes and Vascular Disease PreterAx and DiamicronN Controlled Evaluation trial. Analyses were conducted from Canadian health-care and societal perspectives. Deterministic and probabilistic sensitivity analyses were conducted to assess results robustness. RESULTS: Over a lifetime horizon, the PRS was a dominant strategy, from both a health-care system and societal perspective. The PRS was less expensive and more efficacious in terms of quality-adjusted life-years compared with usual screening technics. Deterministic and probabilistic sensitivity analyses showed that results remained dominant in most simulations. CONCLUSIONS: This economic evaluation demonstrates that the PRS is a dominant option compared with usual screening methods for the prevention of DN in patients with T2D. Adoption of the PRS would reduce costs saving but would also help prevent ESRD and improve patients' quality of life.

Correction: A mathematical model describing the localization and spread of influenza A virus infection within the human respiratory tract.

[This corrects the article DOI: 10.1371/journal.pcbi.1007705.].

Quantification of Ebola virus replication kinetics in vitro.

Mathematical modelling has successfully been used to provide quantitative descriptions of many viral infections, but for the Ebola virus, which requires biosafety level 4 facilities for experimentation, modelling can play a crucial role. Ebola virus modelling efforts have primarily focused on in vivo virus kinetics, e.g., in animal models, to aid the development of antivirals and vaccines. But, thus far, these studies have not yielded a detailed specification of the infection cycle, which could provide a foundational description of the virus kinetics and thus a deeper understanding of their clinical manifestation. Here, we obtain a diverse experimental data set of the Ebola virus infection in vitro, and then make use of Bayesian inference methods to fully identify parameters in a mathematical model of the infection. Our results provide insights into the distribution of time an infected cell spends in the eclipse phase (the period between infection and the start of virus production), as well as the rate at which infectious virions lose infectivity. We suggest how these results can be used in future models to describe co-infection with defective interfering particles, which are an emerging alternative therapeutic.

Quantifying mechanistic traits of influenza viral dynamics using in vitro data.

When analysing in vitro data, growth kinetics of influenza virus strains are often compared by computing their growth rates, which are sometimes used as proxies for fitness. However, analogous to mathematical models for epidemics, the growth rate can be defined as a function of mechanistic traits: the basic reproduction number (the average number of cells each infected cell infects) and the mean generation time (the average length of a replication cycle). Fitting a model to previously published and newly generated data from experiments in human lung cells, we compared estimates of growth rate, reproduction number and generation time for six influenza A strains. Of four strains in previously published data, A/Canada/RV733/2003 (seasonal H1N1) had the lowest basic reproduction number, followed by A/Mexico/INDRE4487/2009 (pandemic H1N1), then A/Indonesia/05/2005 (spill-over H5N1) and A/Anhui/1/2013 (spill-over H7N9). This ordering of strains was preserved for both generation time and growth rate, suggesting a positive biological correlation between these quantities which have not been previously observed. We further investigated these potential correlations using data from reassortant viruses with different internal proteins (from A/England/195/2009 (pandemic H1N1) and A/Turkey/05/2005 (H5N1)), and the same surface proteins (from A/Puerto Rico/8/34 (lab-adapted H1N1)). Similar correlations between traits were observed for these viruses, confirming our initial findings and suggesting that these patterns were related to the degree of human adaptation of internal genes. Also, the model predicted that strains with a smaller basic reproduction number, shorter generation time and slower growth rate underwent more replication cycles by the time of peak viral load, potentially accumulating mutations more quickly. These results illustrate the utility of mathematical models in inferring traits driving observed differences in in vitro growth of influenza strains.

Real-World Experience With Apremilast in the Treatment of Adults With Moderate to Severe Plaque Psoriasis in Québec: A Claims-Based Analysis of Drug Utilization and Healthcare Resource Utilization.

BACKGROUND: In Québec, targeted biologic therapies for moderate to severe plaque psoriasis are restricted to patients who have not responded to phototherapy or conventional systemic treatment, primarily due to high drug costs. Apremilast, an oral treatment for plaque psoriasis, was added to the Québec provincial health insurance plan (Régie de l'assurance maladie du Québec; RAMQ) formulary in 2015, making this the only province in Canada with public drug plan reimbursement for apremilast. OBJECTIVES: The aim of this study is to describe patients' characteristics, treatment patterns, healthcare resource utilization (HCRU), and associated costs and to measure real-world budget impact of using apremilast before biologics in plaque psoriasis. METHODS: This study was performed using RAMQ drug claims and medical services data. Patients diagnosed with psoriasis between January 2015 and December 2017 were identified. Medical services and prescription claims were categorized as all-cause and psoriasis-related. Using RAMQ database estimates, a 3-year budget impact analysis was developed comparing treatment cost with and without the addition of apremilast to the formulary. RESULTS: In all, 540 patients were identified (apremilast: n = 92; biologics: n = 448). Comorbidity burden and treatment persistence and adherence were comparable between apremilast and biologic users. The year following the index date, all-cause HCRU was lower for apremilast versus biologic users (CAN$19 763 vs CAN$28 025; P < .01), mainly driven by drug cost. Using apremilast before biologics resulted in an estimated RAMQ net savings of CAN$49 290 (2015), CAN$746 856 (2016), and CAN$1 216 512 (2017), and a total savings of CAN$2 012 658 since apremilast's addition to the formulary. CONCLUSION: Adding apremilast to the drug formulary of other Canadian provinces could result in significant healthcare savings.