Spatial omics reveals molecular changes in focal cortical dysplasia type II

Focal cortical dysplasia (FCD) represents a group of diverse localized cortical lesions that are highly epileptogenic and occur due to abnormal brain development caused by genetic mutations, involving the mammalian target of rapamycin (mTOR). These somatic mutations lead to mosaicism in the affected brain, posing challenges to unravel the direct and indirect functional consequences of these mutations. To comprehensively characterize the impact of mTOR mutations on the brain, we employed here a multimodal approach in a preclinical mouse model of FCD type II (Rheb), focusing on spatial omics techniques to define the proteomic and lipidomic changes. Mass Spectrometry Imaging (MSI) combined with fluorescence imaging and label free proteomics, revealed insight into the brain's lipidome and proteome within the FCD type II affected region in the mouse model. MSI visualized disrupted neuronal migration and differential lipid distribution including a reduction in sulfatides in the FCD type II-affected region, which play a role in brain myelination. MSI-guided laser capture microdissection (LMD) was conducted on FCD type II and control regions, followed by label free proteomics, revealing changes in myelination pathways by oligodendrocytes. Surgical resections of FCD type IIb and postmortem human cortex were analyzed by bulk transcriptomics to unravel the interplay between genetic mutations and molecular changes in FCD type II. Our comparative analysis of protein pathways and enriched Gene Ontology pathways related to myelination in the FCD type II-affected mouse model and human FCD type IIb transcriptomics highlights the animal model's translational value. This dual approach, including mouse model proteomics and human transcriptomics strengthens our understanding of the functional consequences arising from somatic mutations in FCD type II, as well as the identification of pathways that may be used as therapeutic strategies in the future.

Homozygosity predominantly affects hypertrophic cardiomyopathy minor genes in an Egyptian clinical cohort

Background

Consanguinity is prevalent in Egypt (35%) resulting in a high incidence of homozygosity. The influence of homozygosity on the genetics of Hypertrophic Cardiomyopathy (HCM) has not been adequately studied.

Purpose

The purpose of this study is to define the genetic architecture of HCM in Egypt using ethnically-matched case and control cohorts.

Methods

Prospective Egyptian patients (n=514) and controls (n=400) were recruited to Aswan Heart Centre for clinical phenotyping and genetic testing for 174 genes implicated in inherited cardiac conditions (Illumina). Rare variation (gnomAD filtering allele frequency ≤4x10–5) in 13 validated HCM genes were classified according to the American College of Medical Genetics (ACMG) guidelines and compared with a prospective HCM cohort of predominantly European ancestry (n=684).

Results

Significantly fewer rare variants detected in Egyptian patients could be classified as (likely) pathogenic compared to Europeans (40.8% vs. 61.6%, p-value=1.6x10–5). Incorporating analysis from these Egyptian case-control cohorts into the ACMG guidelines increased this yield to 53.8%. Homozygous variants were more frequently observed in Egyptian patients (4.1% vs 0.1%, p-value=2x10–7), with variants in the minor HCM genes MYL2, MYL3 and CSRP3 more likely to present in homozygosity than the major genes (MYH7, MYBPC3 and troponins), suggesting such variants are less penetrant in the heterozygous state.

Conclusions

The integration of Egyptian-specific genetic and phenotypic data significantly improves variant interpretation in HCM and consequently the precision of genetic testing. The observed prevalence of homozygosity and rare variation in minor HCM genes in Egyptian patients provides important insights into its disease-mechanisms and genetics.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Science and Technology Development FundAl Alfi Foundation

Setup of human liver-chips integrating 3D models, microwells and a standardized microfluidic platform as proof-of-concept study to support drug evaluation

Human 3D liver microtissues/spheroids are powerful in vitro models to study drug-induced liver injury (DILI) but the small number of cells per spheroid limits the models' usefulness to study drug metabolism. In this work, we scale up the number of spheroids on both a plate and a standardized organ-chip platform by factor 100 using a basic method which requires only limited technical expertise. We successfully generated up to 100 spheroids using polymer-coated microwells in a 96-well plate (= liver-plate) or organ-chip (= liver-chip). Liver-chips display a comparable cellular CYP3A4 activity, viability, and biomarker expression as liver spheroids for at least one week, while liver-plate cultures display an overall reduced hepatic functionality. To prove its applicability to drug discovery and development, the liver-chip was used to test selected reference compounds. The test system could discriminate toxicity of the DILI-positive compound tolcapone from its less hepatotoxic structural analogue entacapone, using biochemical and morphological readouts. Following incubation with diclofenac, the liver-chips had an increased metabolite formation compared to standard spheroid cultures. In summary, we generated a human liver-chip model using a standardized organ-chip platform which combines up to 100 spheroids and can be used for the evaluation of both drug safety and metabolism.

Prediction of Chameleonic Efficiency

Chameleonic properties, i. e., the capacity of a molecule to hide polarity in non-polar environments and expose it in water, help achieving sufficient permeability and solubility for drug molecules with high MW. We present models of experimental measures of polarity for a set of 24 FDA approved drugs (MW 405-1113) and one PROTAC (MW 1034). Conformational ensembles in aqueous and non-polar environments were generated using molecular dynamics. A linear regression model that predicts chromatographic apparent polarity (EPSA) with a mean unsigned error of 10 Ų was derived based on separate terms for donor, acceptor, and total molecular SASA. A good correlation (R² =0.92) with an experimental measure of hydrogen bond donor potential, Δlog P_oct-tol , was found for the mean hydrogen bond donor SASA of the conformational ensemble scaled with Abraham's A hydrogen bond acidity. Two quantitative measures of chameleonic behaviour, the chameleonic efficiency indices, are introduced. We envision that the methods presented herein will be useful to triage designed molecules and prioritize those with the best chance of achieving acceptable permeability and solubility.

A cryogenic continuously rotating half-wave plate mechanism for the POLARBEAR-2b cosmic microwave background receiver

We present the design and laboratory evaluation of a cryogenic continuously rotating half-wave plate (CHWP) for the POLARBEAR-2b (PB-2b) cosmic microwave background receiver, the second installment of the Simons Array. PB-2b will observe at 5200 m elevation in the Atacama Desert of Chile in two frequency bands centered at 90 GHz and 150 GHz. In order to suppress atmospheric 1/f noise and mitigate systematic effects that arise when differencing orthogonal detectors, PB-2b modulates linear sky polarization using a CHWP rotating at 2 Hz. The CHWP has a 440 mm clear aperture diameter and is cooled to ≈50 K in the PB-2b receiver cryostat. It consists of a low-friction superconducting magnetic bearing and a low-torque synchronous electromagnetic motor, which together dissipate <2 W. During cooldown, a grip-and-release mechanism centers the rotor to <0.5 mm, and during continuous rotation, an incremental optical encoder measures the rotor angle with a noise level of 0.1 μrad/Hz. We discuss the experimental requirements for the PB-2b CHWP, the designs of its various subsystems, and the results of its evaluation in the laboratory. The presented CHWP has been deployed to Chile and is expected to see first light on PB-2b in 2020 or 2021.

The genetic architecture of left ventricular non-compaction reveals both substantial overlap with other cardiomyopathies and a distinct aetiology in a subset of cases

Background

Left ventricular non-compaction (LVNC) is a condition characterised by trabeculations in the myocardial wall and is the subject of considerable conjecture as to whether it represents a distinct pathology or a secondary phenotype associated with other cardiac diseases, particularly cardiomyopathies.

Purpose

To investigate the genetic architecture of LVNC by identifying genes and variant classes robustly associated with disease and comparing these to other genetically characterised cardiomyopathies.

Methods

We performed rare variant association analysis using six different LVNC cohorts comprising 840 cases together with 125,748 gnomAD population controls and compared results to similar analyses with dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM) cases.

Results

We observed substantial overlap in genes and variant classes enriched in LVNC and DCM/HCM, indicating that in many cases LVNC belongs to a spectrum of more established cardiomyopathies, with non-compaction representing a phenotypic variation in patients with DCM- or HCM-causing variants. In contrast, five variant classes were uniquely enriched in LVNC cases, of which truncating variants in MYH7, ACTN2 and PRDM16 may represent a distinct LVNC aetiology. MYH7 truncating variants are generally considered as non-pathogenic but were detected in 2% of LVNC cases compared to 0.1% of controls, including a cluster of variants around a single splice region. Additionally, structural variants (exon deletions) in RYR2 and missense variants in the transmembrane region of HCN4 were enriched in LVNC cases, confirming prior reports regarding the association of these variant classes with combined LVNC and arrhythmia phenotypes.

Conclusions

We demonstrated that genetic association analysis can clarify the relationship between LVNC and established cardiomyopathies, highlighted substantial overlap with DCM/HCM but also identified variant classes associated with distinct LVNC and with joint LVNC/arrhythmia phenotypes. These results underline the complex genetic landscape of LVNC and inform how genetic testing in LVNC cases should be pursued and interpreted.

Cardiomyopathy rare variant frequencies

Funding Acknowledgement

Type of funding source: None

Development and Characterization of a Human Hepatocyte Low Intrinsic Clearance Assay for Use in Drug Discovery

Progression of new chemical entities is a multiparametric process involving a balance of potency; absorption, distribution, metabolism, and excretion; and safety properties. To accurately predict human pharmacokinetics and estimate human efficacious dose, the use of in vitro measures of clearance is often essential. Low metabolic clearance is often targeted to facilitate in vivo exposure and achieve appropriate half-life. Suspension primary human hepatocytes (PHHs) have been successfully used in predictions of clearance. However, incubation times are limited, hindering the limit of quantification. The aims herein were to evaluate the ability of a novel PHH media supplement, HepExtend, in order to maintain cell function, increase culture times, and define the clearance of stable compounds. Cell activity was analyzed with a range of cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) substrates, and the mRNA expression of drug disposition and toxicity marker genes was determined. HepExtend and Geltrex were essential to maintain cell activity and viability for 5 days (N = 3 donors). In comparison with CM4000 ± Geltrex, HepExtend + Geltrex displayed a higher level of gene expression on day 1, particularly for the P450s, nuclear receptors, and UGTs. The novel medium, HepExtend + Geltrex, was robust and reproducible in generating statistically significant intrinsic clearance values at 0.1 µl/min/10⁶ cells over a 30-hour period (P < 0.05), which was lower than previously demonstrated. Following regression correction, human hepatic in vivo clearance was predicted within 3-fold for 83% of compounds tested for three human donors, with an average fold error of 2.2. The novel PHH medium, HepExtend, with matrix overlay offers significant improvement in determining compounds with low intrinsic clearance when compared with alternative approaches.

Bioanalysis of Pseudomonas aeruginosa alkyl quinolone signalling molecules in infected mouse tissue using LC-MS/MS; and its application to a pharmacodynamic evaluation of MvfR inhibition

Alkyl quinolone molecules 2-heptyl-4-quinolone (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS) are important quorum sensing signals, which play a mediatory role in the pathogenesis of acute and chronic Pseudomonas aeruginosa infection. A targeted approach inhibiting the bacterial 'multiple virulence factor regulon' (MvfR) protein complex, offers the possibility to block the synthesis of MvfR-dependant signal molecules. Here, a high throughput bioanalytical method was developed using LC-MS/MS detection for the selective determination of HHQ and PQS in mouse tissue homogenate, over a sensitive range of 1-5000 and 10-5000pg/mL, respectively. Chromatographic peak distortion of the iron chelator PQS was overcome with the applied use of a bidentate chelator mobile phase additive 2-Picolinic acid at 0.2mM concentration, giving an improved separation and response for the analyte, whilst maintaining overall MS system robustness. Following thigh infection with P. aeruginosa strain 2-PA14 in mice, the concentration and time course of HHQ and PQS (4-hydroxy-2-alkyl-quinolone (HAQ) biomarkers) residing in the biophase were evaluated, and exhibited a low level combined with a substantial inter-individual variability. Quantifiable levels could be obtained from approximately 15h post infection, to the study termination at 21-22h. A dose dependant reduction in HAQ tissue concentrations at selected time points were obtained following MvfR inhibitor administration versus drug vehicle (p<0.01, Kruskal-Wallis-one way ANOVA) and meta -analyses of several studies enabled an inhibitory concentration (IC₅₀) of 80nM free drug to be determined. However, due to the experimental limitations a defined time profile for in-vivo HAQ production could not be characterised. Microsomal stability measurements demonstrated a rapid metabolic clearance of both alkyl quinolone biomarkers in the bacterial host, with a hepatic extraction ratio greater than 0.96 (the measurable assay limit). High clearance underpinned the low concentrations present in the well-perfused thigh tissue. Along with method development and validation details, this paper considers the kinetics of in-vivo HAQ bio-synthesis during Pseudomonas infection; and risks of biomarker over-estimation from samples which contain an exogenous population of bacteria.

Hepatic drug transporters: the journey so far

INTRODUCTION

The key role of transporter biology in both the manifestation and treatment of disease is now firmly established. Experiences of sub-optimal drug exposure due to drug-transporter interplay have supported incorporation of studies aimed at understanding the interactions between compounds and drug transporters much earlier in drug discovery. While drug transporters can impact the most pivotal pharmacokinetic parameter with respect to human dose and exposure projections, clearance, at a renal or hepatobiliary level, the latter will form the focus of this perspective.

AREAS COVERED

A synopsis of guidelines on which transporters to study together with an overview of the currently available toolkit is presented. A perspective on when to conduct studies with various hepatic transporters is also provided together with structural "alerts" which should prompt early investigation.

EXPERT OPINION

Great progress has been made in individual laboratories and via consortia to understand the role of drug transporters in disease, drug disposition, drug-drug interactions and toxicity. A systematic analysis of the value posed by the available approaches and an inter-lab comparison now seems warranted. The emerging ability to use physico-chemical properties to guide future screening cascades promises to revolutionise the efficiency of early drug discovery.

A new paradigm for navigating compound property related drug attrition

Improving the efficiency of drug discovery remains a major focus for the pharmaceutical industry. Toxicity accounts for 90% of withdrawals and major early-stage terminations relate to suboptimal efficacy and safety. Traditional oral drug space is well defined with respect to physicochemical properties and ADMET risks but increased focus on ligand-lipophilicity efficiency, maximizing enthalpy contributions and new target classes challenge this paradigm. A hybrid space has been identified that combines physical properties and key interactions attributable to drug transporters. A novel algorithm is proposed that incorporates drug-transporter interactions and its utility evaluated against popular ligand efficiency indices. Simply reducing the bulk properties of compounds can exchange one problem for another and creates high-risk areas that challenge the successful delivery from a balanced portfolio.

Should General Practitioners Issue a Sick Certificate to Employees Who Consult for Low Back Pain in Primary Care?

PURPOSE

Back pain is a common problem and has significant societal impact. Sickness certification is commonly issued to patients consulting their general practitioner with low back pain. The aim of this study was to investigate the association of certification for low back pain with clinical outcomes and cost consequences.

METHODS

A prospective cohort study using linked questionnaire and medical record data from 806 low back pain patients in 8 UK general practices: comparison of 116 (14.4%) who received a sickness certificate versus 690 who did not receive certification. The primary clinical measure was the Roland and Morris Disability Questionnaire (RMDQ). Data on back pain consultation and work absenteeism were used to calculate healthcare and societal costs.

RESULTS

Participants issued a sickness certificate had higher back-related disability at baseline consultation and 6-month follow-up [mean difference 3.1 (95% CI 1.8, 4.4) on the RMDQ], indicating worse health status. After fully adjusting for baseline differences, most changes in clinical outcomes at 6 months were not significantly different between study groups. Productivity losses were significantly higher for the certification group, with most absence occurring after the expected end of certification; mean difference in costs due to absenteeism over 6 months was £1,956 (95% CI £941, £3040).

CONCLUSIONS

There was no clear evidence of a difference in clinical outcomes between individuals issued a sickness certificate and those not issued a certification for their back pain. With little overall contrast in clinical outcomes, policy makers and care providers may wish to draw on the likely difference in societal costs alongside issues in ethical and moral care in their consideration of patient care for low back pain.

Patient preferences for clinical follow-up after primary treatment for soft tissue sarcoma: a cross-sectional survey and discrete choice experiment

BACKGROUND

Patients treated for soft tissue sarcoma (STS) require long-term follow-up to detect recurrent or metastatic disease, yet marked differences exist in clinical approaches to the length of follow-up, frequency of consultations and investigations undertaken at follow-up visits. There has been no published work assessing patient expectations or the acceptability of post-treatment follow-up strategies. This study aimed to assess the patient acceptability of different follow-up strategies following curative surgery for soft tissue sarcoma and to investigate the hypothetical levels of recurrence risk at which different follow-up regimes were acceptable.

METHODS

Patients were recruited from the Royal Orthopaedic Hospital in Birmingham. The study used a cross-sectional survey incorporating a best-worst scaling discrete choice experiment to assess patient preferences regarding different aspects of follow-up.

RESULTS

132 patients participated (47% response). The nature of investigations undertaken during follow-up was the most important aspect of post-surgical care. Patients typically preferred appointments routinely consisting of clinical examination and chest X-ray, and for follow-up to remain in secondary care rather than general practice.

CONCLUSION

Clear protocols for STS patient follow-up can improve consistency and equity of care. In determining the optimum follow-up plan for STS patients from the patient perspective, this study provides valuable information that should be considered alongside the clinical effectiveness of follow-up strategies to maximise patient outcomes and use NHS resources appropriately.

The Percutaneous shunting in Lower Urinary Tract Obstruction (PLUTO) study and randomised controlled trial: evaluation of the effectiveness, cost-effectiveness and acceptability of percutaneous vesicoamniotic shunting for lower urinary tract obstruction

BACKGROUND

Congenital lower urinary tract obstruction (LUTO) is a disease associated with high perinatal mortality and childhood morbidity. Fetal vesicoamniotic shunting (VAS) bypasses the obstruction with the potential to improve outcome.

OBJECTIVE

To determine the effectiveness, cost-effectiveness and patient acceptability of VAS for fetal LUTO.

DESIGN

A multicentre, randomised controlled trial incorporating a prospective registry, decision-analytic health economic model and preplanned Bayesian analysis using elicited opinions. Patient acceptability was evaluated by interview in a qualitative study.

SETTING

Fetal medicine departments in the UK, Ireland and the Netherlands.

PARTICIPANTS

Pregnant women with a male singleton fetus with LUTO.

INTERVENTIONS

In utero percutaneous VAS compared with conservative care.

MAIN OUTCOME MEASURES

The primary outcome was survival to 28 days. Secondary outcome measures were survival and renal function at 1 year of age, cost of care and cost per additional life-year and per disability-free survival at the end of 1 year.

RESULTS

The trial stopped early with 31 women randomised because of difficulties in recruitment. Of those randomised to VAS and conservative management, 3/16 (19%) and 2/15 (13%), respectively, did not receive their allocated intervention. Based on intention-to-treat analysis, survival at 28 days was higher if allocated VAS (50%) than conservative management (27%) [relative risk (RR) 1.88, 95% confidence interval (CI) 0.71 to 4.96, p = 0.27]. At 12 months survival was 44% in the VAS arm and 20% in the conservative arm (RR 2.19, 95% CI 0.69 to 6.94, p = 0.25). Neither difference was statistically significant. Of survivors at 1 year, two in the VAS arm had no evidence of renal impairment and four in the VAS arm and two in the conservative arm required medical management. One baby in the conservative arm had end-stage renal failure at 1 year. VAS was more expensive because of additional surgery and intensive care. VAS cost £15,500 per survivor at 1 year and £43,900 per disability-free year. Elicited expert opinions showed uncertainty in the effect of VAS at 28 days. In a Bayesian analysis combining elicited opinion with the results, uncertainty of the benefit of VAS remained (RR 1.31, 95% credible interval 0.84 to 2.18). The acceptability study identified visualisation of the fetus during ultrasound scanning, perceiving a personal benefit, and altruism as positive influences on recruitment. Fear of the VAS procedure and the perceived severity of LUTO influenced non-participation. The need for more detailed information about the condition and its implications during pregnancy and following delivery was a further important finding of this research. Recruitment was hampered by logistical and regulatory difficulties, a lower incidence of LUTO and lower antenatal diagnosis rate [estimated to be 3.34 (95% CI 2.95 to 3.72) per 10,000 total births and 47%, respectively, in an associated epidemiological study] and high termination of pregnancy rates. In the registry women also demonstrated a clear preference for conservative management.

CONCLUSIONS

Survival to 28 days and 1 year appears to be higher with VAS than with conservative management, but it is not possible to prove benefit beyond reasonable doubt. Notably, prognosis in both arms for survival and renal function is poor. VAS was substantially more costly and unlikely to be regarded as cost-effective based on the 1-year data. Parents should be counselled about the risks of pregnancy loss with or without VAS insertion. The National Institute for Health and Care Excellence interventional procedures guidance (IPG 202) should be updated to reflect this new evidence. Babies in the PLUTO trial should be followed up long term for the different outcomes.

TRIAL REGISTRATION

ISRCTN53328556.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment ; Vol. 17, No. 59. See the NIHR Journals Library website for further project information.

Sentinel lymph node status in vulval cancer: systematic reviews of test accuracy and decision-analytic model-based economic evaluation

BACKGROUND

Vulval cancer causes 3-5% of all gynaecological malignancies and requires surgical removal and inguinofemoral lymphadenectomy (IFL). Complications affect > 50% of patients, including groin wound infection, lymphoedema and cellulitis. A sentinel lymph node (SLN) is the first groin node with the highest probability of malignancy. SLN biopsy would be useful if it could accurately identify patients in whom cancer has spread to the groin, without removing all groin nodes. SLNs can be identified by isosulfan blue dye and/or technetium-99 ((99m)Tc) radioactive tracer during lymphoscintigraphy. The blue dye/(99m)Tc procedure only detects SLN, not metastases - this requires histological examination, which can include ultrastaging and staining with conventional haematoxylin and eosin (H&E) or immunohistochemistry.

OBJECTIVES

To determine the test accuracy and cost-effectiveness of the SLN biopsy with (99m)Tc and/or blue dye compared with IFL or clinical follow-up for test negatives in vulval cancer, through systematic reviews and economic evaluation.

DATA SOURCES

Standard medical databases, including MEDLINE, EMBASE, Science Citation Index and The Cochrane Library, medical search gateways, reference lists of review articles and included studies were searched to January 2011.

METHODS

For accuracy and effectiveness, standard methods were used and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches were to January 2011, with no language restrictions. Meta-analyses were carried out with Meta-Disc version 1.4 (Javier Zamora, Madrid, Spain) for accuracy; none was appropriate for effectiveness. The economic evaluation from a NHS perspective used a decision-tree model in DATA TreeAge Pro Healthcare 2001 (TreeAge Software, Inc., Williamstown, MA, USA). Six options (blue dye with H&E, blue dye with ultrastaging, (99m)Tc with H&E, (99m)Tc with ultrastaging, blue dye/(99m)Tc with H&E, blue dye/(99m)Tc with ultrastaging) were compared with IFL. Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

For accuracy, of the 26 included studies, most evaluated (99m)Tc/blue dye combined. Four studies had clinical follow-up only for test negatives and five had clinical follow-up for all and IFL for test negatives. Numbers with no SLN found were difficult to distinguish from those with negative SLN biopsies. The largest group of 11 studies using (99m)Tc/blue dye, ultrastaging and immunohistochemistry had a pooled sensitivity of 95.6% [95% confidence interval (CI) 91.5% to 98.1%] and a specificity of 100% (95% CI 99.0% to 100%). Mean SLN detection rates were 94.6% for (99m)Tc, 68.7% for blue dye and 97.7% for both. One study measured global health status quality of life (QoL) and found no difference between SLN biopsy and IFL. One patient preference evaluation showed that 66% preferred IFL rather than a 5% false-negative rate from SLN biopsy. For effectiveness, of 14,038 references, one randomised controlled trial, three case-control studies and 13 case series were found. Approximately 50% died from vulval cancer and 50% from other causes during follow-ups. Recurrences were in the ratio of approximately 4 : 2 : 1 vulval, groin and distant, with more recurrences in node-positive patients. No studies reported QoL. For cost per death averted, IFL was less costly and more effective than strategies using SLN biopsy. For morbidity-free survival and long-term morbidity-free survival, (99m)Tc with ultrastaging was most cost-effective. Strategies with blue dye only and H&E only were never cost-effective. The incremental cost-effectiveness ratio for (99m)Tc with ultrastaging compared with IFL was £4300 per case of morbidity-free survival and £7100 per long-term morbidity-free survival.

LIMITATIONS

The main limitations of this study include the lack of good-quality evidence on accuracy, effectiveness and QoL. A large project such as this takes time to publish, so the most recent studies are not included.

CONCLUSIONS

A sensitive and specific combined metastatic SLN detection test and information on generic QoL in vulval cancer is urgently required.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Sentinel lymph node biopsy in vulval cancer: systematic review and meta-analysis

BACKGROUND

The purpose of this study was to determine the accuracy of sentinel lymph node (SLN) biopsy with technetium 99 (99mTc) and/or blue dye-enhanced lymphoscintigraphy in vulval cancer.

METHODS

Sensitive searches of databases were performed upto October 2013. Studies with at least 75% of women with FIGO stage IB or II vulval cancer evaluating SLN biopsy with 99mTc, blue dye or both with reference standard of inguinofemoral lymphadenectomy (IFL) or clinical follow-up were included. Meta-analyses were performed using Meta-Disc version 1.4.

RESULTS

Of the 2950 references, 29 studies (1779 women) were included; most of them evaluated 99mTc combined with blue dye. Of these, 24 studies reported results for SLN followed by IFL, and 5 reported clinical follow-up only for SLN negatives. Pooling of all studies was inappropriate because of heterogeneity. Mean SLN detection rates were 94.0% for 99mTc, 68.7% for blue dye and 97.7% for both. SLN biopsy had pooled sensitivity of 95% (95% CI 92-98%) with negative predictive value (NPV) of 97.9% in studies using 99mTc/blue dye, ultrastaging and immunohistochemistry with IFL as reference. Pooled sensitivity for SLN with clinical follow-up for SLN-negatives was 91% (85-95%) with NPV 95.6%. Patients undergoing SLN biopsy experienced less morbidity than those undergoing IFL.

CONCLUSIONS

Sentinel lymph node biopsy using 99mTC, blue dye and ultrastaging with immunohistochemistry is highly accurate when restricted to carefully selected patients, within a rigorous protocol, with close follow-up and where sufficient numbers for learning curve optimisation exist. Patients must make an informed choice between the slightly higher groin recurrence rates of SLN biopsy vs the greater morbidity of IFL.

Cost-effectiveness of transcatheter aortic valve implantation (TAVI) for aortic stenosis in patients who are high risk or contraindicated for surgery: a model-based economic evaluation

BACKGROUND

Calcific aortic stenosis (AS) is a common valvular heart disease. Patients with severe symptomatic AS typically survive less than 3 years. In such patients, intervention with surgical aortic valve replacement (SAVR) may increase survival. However, in some patients SAVR is associated with a high operative risk and medical management is considered appropriate. Transcatheter aortic valve implantation (TAVI) is a relatively recent technique to avoid the invasiveness of open surgery. This procedure has been used for the treatment of patients with severe AS who are unsuitable for SAVR (because it is too high risk and/or for other reasons such as suffering from porcelain aorta) and is increasingly being considered for other patients.

OBJECTIVES

To determine the cost-effectiveness of TAVI being made available for patients who are high risk or contraindicated for SAVR through a review of existing economic evaluations and development of a model.

DATA SOURCES AND REVIEW METHODS

Bibliographic databases [MEDLINE, EMBASE, The Cochrane Library, Health Technology Assessment (HTA), Database of Abstracts of Reviews of Effects (DARE) and NHS Economic Evaluation Database (EED), Centre for Reviews and Dissemination HTA, DARE and NHS EED], guideline resources, current trials registers, websites/grey literature and manufacturers' websites, and consultation with clinical experts were used to identify studies for the review and information for the model. Databases were searched from 2007 to November 2010. A model was built to assess the cost-effectiveness of TAVI separately in patients suitable and unsuitable for SAVR, together with overall results for the effect of making TAVI available. Substantial deterministic sensitivity analysis was carried out together with probabilistic sensitivity analysis.

RESULTS

No fully published cost-effectiveness studies were found. Modelling patients not suitable for SAVR, the base-case results show TAVI as more costly but more effective than medical management, with an incremental cost-effectiveness ratio (ICER) of £12,900 per quality-adjusted life-year (QALY). The ICER was below £20,000 per QALY for over 99% of model runs in the probabilistic sensitivity analysis. For patients suitable for SAVR, the comparator with TAVI is a mixture of SAVR and medical management. TAVI is both more costly and less effective than this comparator assuming that most patients would receive SAVR in the absence of TAVI. This is robust to a number of assumption changes about the effects of treatment, but sensitive to assumptions about the proportion of patients receiving SAVR in the comparator. If the use of TAVI is extended to include more patients suitable for SAVR, the overall results from the model become less favourable for TAVI.

LIMITATIONS

The modelling involves extrapolation of short-term data and the comparison between TAVI and SAVR is not based on randomised data. More trial data on the latter have been published since the modelling was undertaken.

CONCLUSIONS

The results for TAVI compared with medical management in patients unsuitable for surgery are reasonably robust and suggest that TAVI is likely to be cost-effective. For patients suitable for SAVR, TAVI could be both more costly and less effective than SAVR. The overall results suggest that, if a very substantial majority of TAVI patients are those unsuitable for SAVR, the cost-effectiveness of a broad policy of introducing TAVI may fall below £20,000 per QALY. Future work required includes the incorporation of new data made available after completion of this work.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

A systematic review and economic evaluation of subcutaneous and sublingual allergen immunotherapy in adults and children with seasonal allergic rhinitis

BACKGROUND

Severe allergic rhinitis uncontrolled by conventional medication can substantially affect quality of life. Immunotherapy involves administering increasing doses of a specific allergen, with the aim of reducing sensitivity and symptomatic reactions. Recent meta-analyses have concluded that both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are more effective than placebo in reducing symptoms. It is uncertain which route of administration is more effective and whether or not treatment is cost-effective.

OBJECTIVE

To determine the comparative clinical effectiveness and cost-effectiveness of SCIT and SLIT for seasonal allergic rhinitis in adults and children.

DATA SOURCES

Electronic databases {MEDLINE, EMBASE, The Cochrane Library [Cochrane Central Register of Controlled Trials (CENTRAL)], NHS Economic Evaluation Database (NHS EED)} and trial registries (from inception up to April 2011).

REVIEW METHODS

Standard systematic review methods were used for study selection, data extraction and quality assessment. Double-blind randomised, placebo-controlled trials of SCIT or SLIT, or of SCIT compared with SLIT, and economic evaluations were included. Meta-analysis and indirect comparison meta-analysis and meta-regression were carried out. A new economic model was constructed to estimate cost-utility.

RESULTS

Meta-analyses found statistically significant effects for SCIT and SLIT compared with placebo across a number of outcome measures and for the vast majority of subgroup analyses (type and amount of allergen, duration of treatment). There was less evidence for children, but some results in favour of SLIT were statistically significant. Indirect comparisons did not provide conclusive results in favour of either SCIT or SLIT. Economic modelling suggested that, when compared with symptomatic treatment (ST), both SCIT and SLIT may become cost-effective at a threshold of £20,000-30,000 per quality-adjusted life-year (QALY) from around 6 years, or 5 years for SCIT compared with SLIT (NHS and patient perspective).

LIMITATIONS

It is uncertain to what extent changes in the outcome measures used in the trials translate into clinically meaningful benefits. Cost-effectiveness estimates are based on a simple model, limited data and a number of assumptions, and should be seen as indicative only.

CONCLUSIONS

A benefit from both SCIT and SLIT compared with placebo has been consistently demonstrated, but the extent of this effectiveness in terms of clinical benefit is unclear. Both SCIT and SLIT may be cost-effective compared with ST from around 6 years (threshold of £20,000-30,000 per QALY). Further research is needed to establish the comparative effectiveness of SCIT compared with SLIT and to provide more robust cost-effectiveness estimates.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Evaluating PET-CT in routine surveillance and follow-up after treatment for cervical cancer: a cost-effectiveness analysis

OBJECTIVE

To undertake a cost-effectiveness analysis that compares positron emission tomography - computed tomography (PET-CT) imaging plus standard practice with standard practice alone in the diagnosis of recurrent or persistent cervical cancer during routine surveillance and follow-up of women who have previously been diagnosed and treated.

DESIGN

Model-based economic evaluation using data from a systematic review, supplemented with data from other sources, and taking a UK National Health Service (NHS) perspective.

SETTING

Secondary Care in England.

POPULATION

Women at least 3 months after the completion of treatment, with either recurrent or persistent cervical cancer.

METHODS

A state transition (Markov) model was developed using TreeAge Pro 2011. The structure of the model was informed by the reviews of the trials and clinical input. In the model, two diagnostic strategies were examined. A one-way sensitivity analysis, probabilistic sensitivity analysis, and a value of information analysis were also carried out.

MAIN OUTCOME MEASURES

Cost-effectiveness based on incremental cost per quality-adjusted life year (QALY).

RESULTS

Adding PET-CT to the current treatment strategy of clinical examination and scanning [magnetic resonance imaging (MRI) and/or CT scan] during the routine surveillance and follow-up of women with recurrent or persistent cervical cancer is significantly more costly, with only a minimal increase in effectiveness. The incremental cost-effectiveness ratio (ICER) for the strategy of PET-CT as an adjunct to the standard treatment strategy that included clinical examination, MRI, and/or CT scan, compared with the usual treatment alone, was over £1 million per QALY.

CONCLUSION

The results of the current analysis suggest that use of PET-CT in the diagnosis of recurrent or persistent cervical cancer is not cost-effective. Current guidelines recommending imaging using PET-CT as a diagnostic or surveillance tool need to be reconsidered in light of these results. This study did not specifically investigate the use of PET-CT in women with symptoms and radiological suspicion of recurrence where exenteration was considered. More research in that specific area is required.

Evaluating PET-CT in the detection and management of recurrent cervical cancer: systematic reviews of diagnostic accuracy and subjective elicitation

BACKGROUND

Positron emission tomography-computed tomography (PET-CT) is recommended to triage women for exenterative surgery and surveillance after treatment for advanced cervical cancer.

OBJECTIVE

To evaluate diagnostic accuracy of additional whole body PET-CT compared with CT/magnetic resonance imaging (MRI) alone in women with suspected recurrent/persistent cervical cancer and in asymptomatic women as surveillance.

DESIGN

Systematic reviews. Subjective elicitation to supplement diagnostic information.

SEARCH STRATEGY/SELECTION CRITERIA/DATA COLLECTION AND ANALYSIS

Searches of electronic databases were performed to June 2013. Studies in women with suspected recurrent/persistent cervical cancer and in asymptomatic women undergoing follow up with sufficient numeric data were included. We calculated sensitivity, specificity and corresponding 95% confidence intervals. Meta-analyses employed a bivariate model that included a random-effects term for between-study variations (CT studies) and univariate random effects meta-analyses (PET-CT studies) for sensitivity and specificity separately.

SUBJECTIVE ELICITATION

Prevalence of recurrence and the accuracy of imaging elicited using the allocation of points technique. Coherence of elicited subjective probabilities with estimates in the literature examined.

RESULTS

We identified 15 relevant studies; none directly compared additional PET-CT with MRI or CT separately. Most CT and MRI studies used older protocols and the majority did not distinguish between asymptomatic and symptomatic women. Meta-analysis of nine PET-CT studies in mostly symptomatic women showed sensitivity of 94.8 (95% CI 91.2-96.9), and specificity of 86.9% (95% CI 82.2-90.5). The summary estimate of the sensitivity of CT for detection of recurrence was 89.64% (95% CI 81.59-94.41) and specificity was 76% (95% CI 43.68-92.82). Meta-analysis for MRI test accuracy studies was not possible because of clinical heterogeneity. The sensitivity and specificity of MRI in pelvic recurrence varied between 82 and 100% and between 78 and 100%, respectively. Formal statistical comparisons of the accuracy of index tests were not possible. Subjective elicitation provided estimates comparable to the literature. Subjective estimates of the increase in accuracy from the addition of PET-CT were less than elicited increases required to justify the use in PET-CT for surveillance.

CONCLUSION

Evidence to support additional PET-CT is scarce, of average quality and does not distinguish between application for surveillance and diagnosis. Guidelines recommending PET-CT in recurrent cervical cancer need to be reconsidered in the light of the existing evidence base.

Cost-effectiveness of sentinel lymph node biopsy vs inguinofemoral lymphadenectomy in women with vulval cancer

Background:

This study examines the cost-effectiveness of sentinel lymph node biopsy, a potentially less morbid procedure, compared with inguinofemoral lymphadenectomy (IFL) among women with stage I and stage II vulval squamous cell carcinoma.

Methods:

A model-based economic evaluation was undertaken based on clinical evidence from a systematic review of published sources. A decision tree model was developed with the structure being informed by clinical input, taking the perspective of the health-care provider.

Results:

For overall survival for 2 years, IFL was found to be the most cost-effective option and dominated all other strategies, being the least costly and most effective. For morbidity-free related outcomes for 2 years, sentinel lymph node (SLN) biopsy with 99mTc and blue dye and haematoxylin & eosin (H&E) histopathology, with ultrastaging and immunohistochemistry reserved for those that test negative following H&E is likely to be the most effective approach.

Conclusion:

SLN biopsy using 99mTc and blue dye with ultrastaging may be considered the most cost-effective strategy based on the outcome of survival free of morbidity for 2 years. The findings here also indicate that using blue dye and H&E for the identification of the SLN and the identification of metastasis, respectively, are not sensitive enough to be used on their own.

Positron emission tomography/computerised tomography imaging in detecting and managing recurrent cervical cancer: systematic review of evidence, elicitation of subjective probabilities and economic modelling

BACKGROUND

Cancer of the uterine cervix is a common cause of mortality in women. After initial treatment women may be symptom free, but the cancer may recur within a few years. It is uncertain whether it is more clinically effective to survey asymptomatic women for signs of recurrence or to await symptoms or signs before using imaging.

OBJECTIVES

This project compared the diagnostic accuracy of imaging using positron emission tomography/computerised tomography (PET-CT) with that of imaging using CT or magnetic resonance imaging (MRI) alone and evaluated the cost-effectiveness of adding PET-CT as an adjunct to standard practice.

DATA SOURCES

Standard systematic review methods were used to obtain and evaluate relevant test accuracy and effectiveness studies. Databases searched included MEDLINE, EMBASE, Science Citation Index and The Cochrane Library. All databases were searched from inception to May 2010.

REVIEW METHODS

Study quality was assessed using appropriately modified Quality Assessment of Diagnostic Accuracy Studies (QUADAS) criteria. Included were any studies of PET-CT, MRI or CT compared with the reference standard of histopathological findings or clinical follow-up in symptomatic women suspected of having recurrent or persistent cervical cancer and in asymptomatic women a minimum of 3 months after completion of primary treatment. Subjective elicitation of expert opinion was used to supplement diagnostic information needed for the economic evaluation. The effectiveness of treatment with chemotherapy, radiotherapy, chemoradiotherapy, radical hysterectomy and pelvic exenteration was systematically reviewed. Meta-analysis was carried out in RevMan 5.1 (The Cochrane Collaboration, The Nordic Cochrane Centre, Copenhagen, Denmark) and Stata version 11 (StataCorp LP, College Station, Texas, USA). A Markov model was developed to compare the relative cost-effectiveness using TreeAge Pro software version 2011 (TreeAge Software Inc., Evanston, IL, USA).

RESULTS

For the diagnostic review, a total of 7524 citations were identified, of which 12 test accuracy studies were included in the review: six studies evaluated PET-CT, two evaluated MRI, three evaluated CT and one evaluated both MRI and CT. All studies were small and the majority evaluated imaging in women in whom recurrence was suspected on the basis of symptoms. The PET-CT studies evaluated local and distant recurrence and most used methods similar to current practice, whereas five of the six CT and MRI studies evaluated local recurrence only and not all employed currently used methods. Meta-analysis of PET-CT studies gave a sensitivity of 92.2% [95% confidence interval (CI) 85.1% to 96.0%] and a specificity of 88.1% (95% CI 77.9% to 93.9%). MRI sensitivities and specificities varied between 82% and 100% and between 78% and 100%, respectively, and CT sensitivities and specificities varied between 78% and 93% and between 0% and 95%, respectively. One small study directly compared PET-CT with older imaging methods and showed more true-positives and fewer false-negatives with PET-CT. The subjective elicitation from 21 clinical experts gave test accuracy results for asymptomatic and symptomatic women and the results for symptomatic women were similar to those from the published literature. Their combined opinions also suggested that the mean elicited increase in accuracy from the addition of PET-CT to MRI and/or CT was less than the elicited minimum important difference in accuracy required to justify the routine addition of PET-CT for the investigation of women after completion of primary treatment. For the effectiveness review, a total of 24,943 citations were identified, of which 62 studies were included (chemotherapy, 19 randomised controlled trials; radiotherapy or chemoradiotherapy, 16 case series; radical hysterectomy and pelvic exenteration, 27 case series). None provided the effectiveness of cisplatin monotherapy, the most commonly used chemotherapeutic agent in the NHS, compared with supportive care in a background of other treatment such as radiotherapy in recurrent and persistent cervical cancer. The model results showed that adding PET-CT to the current treatment strategy of clinical examination, MRI and/or CT scan was significantly more costly with only a minimal increase in effectiveness, with incremental cost-effectiveness ratios for all models being > £1M per quality-adjusted life-year (QALY) and the additional cost per additional case of recurrence being in the region of £600,000.

LIMITATIONS

There was considerable uncertainty in many of the parameters used because of a lack of good-quality evidence in recurrent or persistent cervical cancer. The evidence on diagnostic and therapeutic impact incorporated in the economic model was poor and there was little information on surveillance of asymptomatic women.

CONCLUSIONS

Given the current evidence available, the addition of PET-CT to standard practice was not found to be cost-effective in the diagnosis of recurrent or persistent cervical cancer. However, although probabilistic sensitivity analysis showed that the main conclusion about cost-ineffectiveness of PET-CT was firm given the range of assumptions made, should more reliable information become available on accuracy, therapeutic impact and effectiveness, and the cost of PET-CT reduce, this conclusion may need revision. Current guidelines recommending imaging for diagnosis using expensive methods such as PET-CT need to be reconsidered in the light of the above.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

In silico physicochemical parameter predictions

Drug discovery is a complex process with the aim of discovering efficacious molecules where their potency and selectivity are balanced against ADMET properties to set the appropriate dose and dosing interval. The link between physicochemical properties and molecular structure are well established. The subsequent connections between physicochemical properties and a drug's biological behavior provide an indirect link back to structure, facilitating the prediction of a biological property as a consequence of a particular molecular manipulation. Due to this understanding, during early drug discovery in vitro physicochemical property assays are commonly performed to eliminate compounds with properties commensurate with high attrition risks. However, the goal is to accurately predict physicochemical properties to prevent the synthesis of high risk compounds and hence minimize wasted drug discovery efforts. This paper will review the relevance to ADMET behaviors of key physicochemical properties, such as ionization, aqueous solubility, hydrogen bonding strength and hydrophobicity, and the in silico methodology for predicting them.

Prucalopride for the treatment of women with chronic constipation in whom standard laxative regimens have failed to provide adequate relief

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of prucalopride for the treatment of women with chronic constipation in whom standard laxative regimens have failed to provide adequate relief. The ERG report is based on the manufacturer's submission (MS) to the National Institute for Health and Clinical Excellence as part of the single technology appraisal process. In the submission, quality-of-life data [Patient Assessment of Constipation Quality of Life (PAC-QOL) and Patient Assessment of Constipation Symptoms (PAC-SYM) questionnaires] from trials of prucalopride were extrapolated to EQ-5D (European Quality of Life-5 Dimensions) data and used to inform effectiveness in an economic model. Response rates to prucalopride were derived from observed response rates in trials, defined as the proportion of patients achieving an average of three or more spontaneous complete bowel movements over the 4- or 12-week trial periods. Adult (18-64 years) and elderly (≥ 65 years) patients were considered separately in the model. Cost-effectiveness was determined from estimated improvements in EQ-5D and anticipated response rates, adjusted for baseline severity of chronic constipation. The ERG considered that the patients participating in these trials were not representative of those in the licensed indication. They were not all refractory to laxatives, and baseline EQ-5D scores showed a large spread in quality of life, with many patients experiencing little baseline dissatisfaction. The mapping of quality-of-life data from trials (PAC-QOL and PAC-SYM data) to EQ-5D was unclear and invalidated. The assumption of the long-term effectiveness and safety of prucalopride to 1 year was considered unjustified. There was no justification or sources given for coefficients used to predict effectiveness in the economic model, and no costs other than the cost of prucalopride were incorporated into the model. Owing to the many areas of uncertainty, particularly the effectiveness of prucalopride in the licensed patient group and its long-term effectiveness and safety, it was considered that the MS provided no evidence for whether prucalopride is effective or not in women with laxative-refractory chronic constipation. Further subgroup analysis of the actual patient group of interest may have better guided decision-making. However, long-term efficacy data, with validated estimates of quality of life incorporated in a well-founded model, would be important for an evidence-based judgement to be made.

Pulse oximetry as a screening test for congenital heart defects in newborn infants: a test accuracy study with evaluation of acceptability and cost-effectiveness

BACKGROUND

Screening for congenital heart defects (CHDs) relies on antenatal ultrasound and postnatal clinical examination; however, life-threatening defects often go undetected.

OBJECTIVE

To determine the accuracy, acceptability and cost-effectiveness of pulse oximetry as a screening test for CHDs in newborn infants.

DESIGN

A test accuracy study determined the accuracy of pulse oximetry. Acceptability of testing to parents was evaluated through a questionnaire, and to staff through focus groups. A decision-analytic model was constructed to assess cost-effectiveness.

SETTING

Six UK maternity units.

PARTICIPANTS

These were 20,055 asymptomatic newborns at ≥ 35 weeks' gestation, their mothers and health-care staff.

INTERVENTIONS

Pulse oximetry was performed prior to discharge from hospital and the results of this index test were compared with a composite reference standard (echocardiography, clinical follow-up and follow-up through interrogation of clinical databases).

MAIN OUTCOME MEASURES

Detection of major CHDs - defined as causing death or requiring invasive intervention up to 12 months of age (subdivided into critical CHDs causing death or intervention before 28 days, and serious CHDs causing death or intervention between 1 and 12 months of age); acceptability of testing to parents and staff; and the cost-effectiveness in terms of cost per timely diagnosis.

RESULTS

Fifty-three of the 20,055 babies screened had a major CHD (24 critical and 29 serious), a prevalence of 2.6 per 1000 live births. Pulse oximetry had a sensitivity of 75.0% [95% confidence interval (CI) 53.3% to 90.2%] for critical cases and 49.1% (95% CI 35.1% to 63.2%) for all major CHDs. When 23 cases were excluded, in which a CHD was already suspected following antenatal ultrasound, pulse oximetry had a sensitivity of 58.3% (95% CI 27.7% to 84.8%) for critical cases (12 babies) and 28.6% (95% CI 14.6% to 46.3%) for all major CHDs (35 babies). False-positive (FP) results occurred in 1 in 119 babies (0.84%) without major CHDs (specificity 99.2%, 95% CI 99.0% to 99.3%). However, of the 169 FPs, there were six cases of significant but not major CHDs and 40 cases of respiratory or infective illness requiring medical intervention. The prevalence of major CHDs in babies with normal pulse oximetry was 1.4 (95% CI 0.9 to 2.0) per 1000 live births, as 27 babies with major CHDs (6 critical and 21 serious) were missed. Parent and staff participants were predominantly satisfied with screening, perceiving it as an important test to detect ill babies. There was no evidence that mothers given FP results were more anxious after participating than those given true-negative results, although they were less satisfied with the test. White British/Irish mothers were more likely to participate in the study, and were less anxious and more satisfied than those of other ethnicities. The incremental cost-effectiveness ratio of pulse oximetry plus clinical examination compared with examination alone is approximately £24,900 per timely diagnosis in a population in which antenatal screening for CHDs already exists.

CONCLUSIONS

Pulse oximetry is a simple, safe, feasible test that is acceptable to parents and staff and adds value to existing screening. It is likely to identify cases of critical CHDs that would otherwise go undetected. It is also likely to be cost-effective given current acceptable thresholds. The detection of other pathologies, such as significant CHDs and respiratory and infective illnesses, is an additional advantage. Other pulse oximetry techniques, such as perfusion index, may enhance detection of aortic obstructive lesions.

FUNDING

The National Institute for Health Research Health Technology programme.

Hysterectomy, endometrial ablation and Mirena® for heavy menstrual bleeding: a systematic review of clinical effectiveness and cost-effectiveness analysis

OBJECTIVE

The aim of this project was to determine the clinical effectiveness and cost-effectiveness of hysterectomy, first- and second-generation endometrial ablation (EA), and Mirena® (Bayer Healthcare Pharmaceuticals, Pittsburgh, PA, USA) for the treatment of heavy menstrual bleeding.

DESIGN

Individual patient data (IPD) meta-analysis of existing randomised controlled trials to determine the short- to medium-term effects of hysterectomy, EA and Mirena. A population-based retrospective cohort study based on record linkage to investigate the long-term effects of ablative techniques and hysterectomy in terms of failure rates and complications. Cost-effectiveness analysis of hysterectomy versus first- and second-generation ablative techniques and Mirena.

SETTING

Data from women treated for heavy menstrual bleeding were obtained from national and international trials. Scottish national data were obtained from the Scottish Information Services Division.

PARTICIPANTS

Women who were undergoing treatment for heavy menstrual bleeding were included.

INTERVENTIONS

Hysterectomy, first- and second-generation EA, and Mirena.

MAIN OUTCOME MEASURES

Satisfaction, recurrence of symptoms, further surgery and costs.

RESULTS

Data from randomised trials indicated that at 12 months more women were dissatisfied with first-generation EA than hysterectomy [odds ratio (OR): 2.46, 95% confidence interval (CI) 1.54 to 3.93; p = 0.0002), but hospital stay [WMD (weighted mean difference) 3.0 days, 95% CI 2.9 to 3.1 days; p < 0.00001] and time to resumption of normal activities (WMD 5.2 days, 95% CI 4.7 to 5.7 days; p < 0.00001) were longer for hysterectomy. Unsatisfactory outcomes associated with first- and second-generation techniques were comparable [12.2% (123/1006) vs 10.6% (110/1034); OR 1.20, 95% CI 0.88 to 1.62; p = 0.2). Rates of dissatisfaction with Mirena and second-generation EA were similar [18.1% (17/94) vs 22.5% (23/102); OR 0.76, 95% CI 0.38 to 1.53; p = 0.4]. Indirect estimates suggested that hysterectomy was also preferable to second-generation EA (OR 2.32, 95% CI 1.27 to 4.24; p = 0.006) in terms of patient dissatisfaction. The evidence to suggest that hysterectomy is preferable to Mirena was weaker (OR 2.22, 95% CI 0.94 to 5.29; p = 0.07). In women treated by EA or hysterectomy and followed up for a median [interquartile range (IQR)] duration of 6.2 (2.7-10.8) and 11.6 (7.9-14.8) years, respectively, 962/11,299 (8.5%) women originally treated by EA underwent further gynaecological surgery. While the risk of adnexal surgery was similar in both groups [adjusted hazards ratio 0.80 (95% CI 0.56 to 1.15)], women who had undergone ablation were less likely to need pelvic floor repair [adjusted hazards ratio 0.62 (95% CI 0.50 to 0.77)] and tension-free vaginal tape surgery for stress urinary incontinence [adjusted hazards ratio 0.55 (95% CI 0.41 to 0.74)]. Abdominal hysterectomy led to a lower chance of pelvic floor repair surgery [hazards ratio 0.54 (95% CI 0.45 to 0.64)] than vaginal hysterectomy. The incidence of endometrial cancer following EA was 0.02%. Hysterectomy was the most cost-effective treatment. It dominated first-generation EA and, although more expensive, produced more quality-adjusted life-years (QALYs) than second-generation EA and Mirena. The incremental cost-effectiveness ratios for hysterectomy compared with Mirena and hysterectomy compared with second-generation ablation were £1440 per additional QALY and £970 per additional QALY, respectively.

CONCLUSIONS

Despite longer hospital stay and time to resumption of normal activities, more women were satisfied after hysterectomy than after EA. The few data available suggest that Mirena is potentially cheaper and more effective than first-generation ablation techniques, with rates of satisfaction that are similar to second-generation techniques. Owing to a paucity of trials, there is limited evidence to suggest that hysterectomy is preferable to Mirena. The risk of pelvic floor surgery is higher in women treated by hysterectomy than by ablation. Although the most cost-effective strategy, hysterectomy may not be considered an initial option owing to its invasive nature and higher risk of complications. Future research should focus on evaluation of the clinical effectivesness and cost-effectiveness of the best second-generation EA technique under local anaesthetic versus Mirena and types of hysterectomy such as laparoscopic supracervical hysterectomy versus conventional hysterectomy and second-generation EA.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

An economic evaluation of positron emission tomography (PET) and positron emission tomography/computed tomography (PET/CT) for the diagnosis of breast cancer recurrence

OBJECTIVES

To review the published economic studies that have evaluated positron emission tomography/computed tomography (PET/CT) in the treatment of recurrent breast cancer, and to develop and carry out a model-based economic evaluation to investigate the relative cost-effectiveness of PET/CT to detect breast cancer recurrence compared with conventional work-up.

DATA SOURCES

A systematic review of economic and diagnostic evidence for PET/CT in diagnosis of breast cancer recurrence. The original databases searched include MEDLINE (Ovid) (1950 to week 5 May 2009), EMBASE (Ovid) (1980 to 2009 week 22) and the NHS Economic Evaluation Database. An updated search was conducted for each database from May 2009 to week 4 April 2010.

METHODS

A decision tree was developed in TREEAGE software (TreeAge Software Inc., Williamstown, MA, USA). The relevant data on accuracy, sensitivity and specificity of each diagnostic test were linked in the model, to costs and the primary outcome measure, cost per quality-adjusted life-year (QALY). The model estimated the mean cost associated with each diagnostic procedure and assumed that patients entering the model were aged 50-75 years. The results of the cost-effectiveness analysis are presented in terms of the incremental cost-effectiveness ratios (ICERs).

RESULTS

The ICER for the strategy of PET compared with conventional work-up was estimated at £29,300 per QALY; the ICER for PET/CT compared with PET was £ 31,000 per QALY; and the ICER for PET/CT combined with conventional work-up versus PET/CT was £ 42,100. Clearly, for each additional diagnostic test that is added to PET, the more expensive the package becomes, but also the more effective it becomes in terms of QALYs gained. The probabilistic sensitivity analysis shows that at a willingness-to-pay threshold of £ 20,000 per QALY, conventional work-up is the preferred option.

LIMITATIONS

Only data from indirect comparisons are available from the accuracy review, and there is some uncertainty about whether the data defining the accuracy of PET/CT present its use as a replacement or as an adjunct to conventional work-up.

CONCLUSIONS

Based on the current model and given the limitations that are apparent in terms of limited availability of data, the result of the current analysis suggests that the use of PET/CT in the diagnosis of recurrent breast cancer in every woman suspected of having a recurrence is unlikely to be cost-effective given the current willingness-to-pay thresholds that are accepted in the UK by decision-making bodies such as the National Institute for Health and Clinical Excellence. Our modelling suggests that conventional work-up could be the most cost-effective diagnostic strategy given current data. Future studies need to secure robust cost data that can be verified from more than one source for the diagnostic tests involved in PET and PET/CT. Reliable and verifiable data on quality of life associated with this clinical condition are also crucial.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Adalimumab, etanercept, infliximab, rituximab and abatacept for the treatment of rheumatoid arthritis after the failure of a tumour necrosis factor inhibitor: a systematic review and economic evaluation

BACKGROUND

Rheumatoid arthritis (RA) is an inflammatory condition that typically causes a symmetrical chronic arthritis. Timely use of disease-modifying antirheumatic drugs (DMARDs) is an essential aspect of disease management, but many patients may not respond even when conventional agents are used optimally.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of adalimumab (ADA), etanercept (ETN), infliximab (IFX), rituximab (RTX) and abatacept (ABT) when used in patients with RA who have tried conventional agents and have failed to improve after trying a first tumour necrosis factor (TNF) inhibitor.

DATA SOURCES

A systematic review of primary studies was undertaken. Databases searched included the Cochrane Library, MEDLINE (Ovid) and EMBASE up to July 2009.

STUDY SELECTION

Two reviewers assessed titles and abstracts of studies identified by the search strategy, obtained the full text of relevant papers and screened them against inclusion criteria.

STUDY APPRAISAL

Data from included studies were extracted by one reviewer and checked by a second. The quality of included studies was assessed independently by two reviewers, with any disagreements resolved by discussion and consultation with a third reviewer if necessary.

RESULTS

Thirty-five studies were included in the systematic review: five randomised controlled trials (RCTs), one comparative study, one controlled study and 28 uncontrolled studies. One RCT (REFLEX) demonstrated the effectiveness of RTX. At 6 months significantly more patients treated with RTX achieved American College of Rheumatology (ACR) 20 [relative risk (RR) = 2.85, 95% confidence interval (CI) 2.08 to 3.91] and ACR70 (RR = 12.14, 95% CI 2.96 to 49.86) compared with those treated with the placebo. Differences between groups in favour of RTX were observed at 6 months for mean change from baseline in Disease Activity Score 28 (DAS28) (mean difference -1.50, 95% CI -1.74 to -1.26) and mean change from baseline in Health Assessment Questionnaire (HAQ) score (mean difference -0.30, 95% CI -0.40 to -0.20). One RCT (ATTAIN) demonstrated the effectiveness of ABT. At 6 months significantly more patients treated with ABT achieved ACR20 (RR = 2.56, 95% CI 1.77 to 3.69) and ACR70 (RR = 6.70, 95% CI 1.62 to 27.80) compared with those treated with placebo. Significant differences between groups in favour of ABT were observed at 6 months for mean change from baseline in DAS28 score (mean difference -1.27, 95% CI -1.62 to -0.93) and mean change from baseline in HAQ score (mean difference -0.34). Twenty-eight uncontrolled studies observed improvement of effectiveness compared with before switching, in patients who switched to ADA, ETN or IFX after discontinued previous TNF inhibitor(s). Four studies were included in the systematic review of cost-effectiveness. Independent economic evaluation undertaken by the assessment group showed that compared with DMARDs, the incremental cost-effectiveness ratios (ICERs) were £34,300 [per quality-adjusted life-year (QALY)] for ADA, £38,800 for ETN, £36,200 for IFX, £21,200 for RTX and £38,600 for ABT. RTX dominates the TNF inhibitors and the ICER for ABT compared with RTX is over £100,000 (per QALY).

LIMITATIONS

Paucity of evidence from RCTs for assessing the clinical effectiveness of TNF inhibitors and an absence of head-to-head trials comparing the five technologies.

CONCLUSIONS

Evidence from RCTs suggests that RTX and ABT are more effective than supportive care. Data from observational studies suggest that the use of an alternative TNF inhibitor in patients who exhibit an inadequate response to a first TNF inhibitor may offer some benefit, but there remain uncertainties with regard to the magnitude of treatment effects and their cost-effectiveness. Future research should include head-to-head trials comparing the clinical effectiveness and cost-effectiveness of the technologies against each other and emerging biologics.

FUNDING

This study was funded by the Health Technology Assessment programme of the National Institute for Health Research.

A Highly Automated Assay for Determining the Aqueous Equilibrium Solubility of Drug Discovery Compounds

Aqueous solubility is an important physicochemical parameter for any potential drug candidate, and high-throughput kinetic assays are frequently used in drug discovery to give an estimate of a compound's aqueous solubility. However, the aqueous solubility data from an equilibrium (thermodynamic) shake-flask technique is considered more relevant, but is slower and more labor intensive to generate. A highly automated aqueous equilibrium solubility shake-flask technique is described and validated on a set of 15 marketed drugs, whose aqueous solubilities cover four orders of magnitude. The assay uses a Tecan Freedom Evo 200 liquid handling robot (Tecan Group Ltd., Männerdorf, Switzerland) with integrated appliances for the transportation, decapping and recapping, and centrifugation of sample tubes. These bespoke automation solutions help overcome the labor intensive steps associated with performing conventional, gold standard, aqueous equilibrium solubility shake-flask measurements, enabling the assay to be used as a primary-wave drug discovery screen.

Prucalopride for the treatment of women with chronic constipation in whom standard laxative regimens have failed to provide adequate relief

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of prucalopride for the treatment of women with chronic constipation in whom standard laxative regimens have failed to provide adequate relief. The ERG report is based on the manufacturer’s submission (MS) to the National Institute for Health and Clinical Excellence as part of the single technology appraisal process. In the submission, quality-of-life data [Patient Assessment of Constipation Quality of Life (PAC-QOL) and Patient Assessment of Constipation Symptoms (PAC-SYM) questionnaires] from trials of prucalopride were extrapolated to EQ-5D (European Quality of Life-5 Dimensions) data and used to inform effectiveness in an economic model. Response rates to prucalopride were derived from observed response rates in trials, defined as the proportion of patients achieving an average of three or more spontaneous complete bowel movements over the 4- or 12-week trial periods. Adult (18–64 years) and elderly (≥ 65 years) patients were considered separately in the model. Cost-effectiveness was determined from estimated improvements in EQ-5D and anticipated response rates, adjusted for baseline severity of chronic constipation. The ERG considered that the patients participating in these trials were not representative of those in the licensed indication. They were not all refractory to laxatives, and baseline EQ-5D scores showed a large spread in quality of life, with many patients experiencing little baseline dissatisfaction. The mapping of quality-of-life data from trials (PAC-QOL and PAC-SYM data) to EQ-5D was unclear and invalidated. The assumption of the long-term effectiveness and safety of prucalopride to 1 year was considered unjustified. There was no justification or sources given for coefficients used to predict effectiveness in the economic model, and no costs other than the cost of prucalopride were incorporated into the model. Owing to the many areas of uncertainty, particularly the effectiveness of prucalopride in the licensed patient group and its long-term effectiveness and safety, it was considered that the MS provided no evidence for whether prucalopride is effective or not in women with laxative-refractory chronic constipation. Further subgroup analysis of the actual patient group of interest may have better guided decision-making. However, long-term efficacy data, with validated estimates of quality of life incorporated in a well-founded model, would be important for an evidence-based judgement to be made.

Clinical effectiveness and cost-effectiveness of stem cell transplantation in the management of acute leukaemia: a systematic review

BACKGROUND

Acute leukaemia is a group of rapidly progressing cancers of bone marrow and blood classified as either acute myeloid leukaemia (AML) or acute lymphoblastic leukaemia (ALL). Haemopoietic stem cell transplantation (SCT) has developed as an adjunct to or replacement for conventional chemotherapy with the aim of improving survival and quality of life.

OBJECTIVES

A systematic overview of the best available evidence on the clinical effectiveness and cost-effectiveness of SCT in the treatment of acute leukaemia.

DATA SOURCES

Clinical effectiveness: electronic databases, including MEDLINE, EMBASE and the Cochrane Library, were searched from inception to December 2008 to identify published systematic reviews and meta-analyses. Cochrane CENTRAL, MEDLINE, EMBASE and Science Citation Index (SCI) were searched from 1997 to March 2009 to identify primary studies. Cost-effectiveness: MEDLINE, EMBASE, Database of Abstracts of Reviews of Effects (DARE) and NHS Economic Evaluation Database (NHS EED) were searched from inception to January 2009.

STUDY SELECTION

Potentially relevant papers were retrieved and independently checked against predefined criteria by two reviewers (one in the case of the cost-effectiveness review).

STUDY APPRAISAL

Included reviews and meta-analyses were critically appraised and data extracted and narratively presented. Included randomised controlled trials (RCTs) and donor versus no donor (DvND) studies were mapped to the evidence covered in existing systematic reviews and meta-analyses according to a framework of 12 decision problems (DPs): DP1 related to SCT in adults with AML in first complete remission (CR1); DP2 to adults with AML in second or subsequent remission or with refractory disease (CR2+); DP3 to children with AML in CR1; DP4 to children with AML in CR2+; DP5 to adults with ALL in CR1; DP6 to adults with ALL in CR2+; DP7 to children with ALL in CR1; DP8 to children with ALL in CR2+; DP9 to comparison of different sources of stem cells in transplantation; DP10 to different conditioning regimens; DP11 to the use of purging in autologous SCT; and DP12 to the use of T-cell depletion in allogeneic SCT.

RESULTS

Fifteen systematic reviews/meta-analyses met the inclusion criteria for the review of clinical effectiveness, thirteen of which were published from 2004 onwards. Taking into account the timing of their publications, most reviews appeared to have omitted an appreciable proportion of potentially available evidence. The best available evidence for effectiveness of allogeneic SCT using stem cells from matched sibling donors came from DvND studies: there was sufficient evidence to support the use of allogeneic SCT in DP1 (except in good-risk patients), DP3 (role of risk stratification unclear) and DP5 (role of risk stratification unclear). There was conflicting evidence in DP7 and a paucity of evidence from DvND studies for all decision problems concerning patient groups in CR2+. The best available evidence for effectiveness of autologous SCT came from RCTs: overall, evidence suggested that autologous SCT was either similar to or less effective than chemotherapy. There was a paucity of evidence from published reviews of RCTs for DPs 9-12. Nineteen studies met the inclusion criteria in the cost-effectiveness review, most reporting only cost information and only one incorporating an economic model. Although there is a wealth of information on costs and some information on cost-effectiveness of allogeneic SCT in adults with AML (DPs 1 and 2), there is very limited evidence on relative costs and cost-effectiveness for other DPs.

LIMITATIONS

Time and resources did not permit critical appraisal of the primary studies on which the reviews/meta-analyses reviewed were based; there were substantial differences in methodologies, and consequently quantitative synthesis of data was neither planned in the protocol nor carried out; some of the studies were quite old and might not reflect current practice; and a number of the studies might not be applicable to the UK.

CONCLUSIONS

Bearing in mind the limitations, existing evidence suggests that sibling donor allogeneic SCT may be more effective than chemotherapy in adult AML (except in good-risk patients) in CR1, childhood AML in CR1 and adult ALL in CR1, and that autologous SCT is equal to or less effective than chemotherapy. No firm conclusions could be drawn regarding the cost-effectiveness of SCT in the UK NHS owing to the limitations given above. Future research should include the impact of the treatments on patients' quality of life as well as information on health service use and costs associated with SCT from the perspective of the UK NHS.