Characteristics and Research Waste Among Randomized Clinical Trials in Gastric Cancer.

Importance: The results of numerous large randomized clinical trials (RCTs) have changed clinical practice in gastric cancer (GC). However, research waste (ie, unpublished data, inadequate reporting, or avoidable design limitations) is still a major challenge for evidence-based medicine. Objectives: To determine the characteristics of GC RCTs in the past 20 years and the presence of research waste and to explore potential targets for improvement. Design, Setting, and Participants: In this cross-sectional study of GC RCTs, ClinicalTrials.gov was searched for phase 3 or 4 RCTs registered from January 2000 to December 2019 using the keyword gastric cancer. Independent investigators undertook assessments and resolved discrepancies via consensus. Data were analyzed from August through December 2020. Main Outcomes and Measures: The primary outcomes were descriptions of the characteristics of GC RCTs and the proportion of studies with signs of research waste. Research waste was defined as unpublished data, inadequate reporting, or avoidable design limitations. Publication status was determined by searching PubMed and Scopus databases. The adequacy of reporting was evaluated using the Consolidated Standards of Reporting Trials (CONSORT) reporting guideline checklist. Avoidable design limitations were determined based on existing bias or lack of cited systematic literature reviews. In the analyses of research waste, 125 RCTs that ended after June 2016 without publication were excluded. Results: A total of 262 GC RCTs were included. The number of RCTs increased from 25 trials in 2000 to 2004 to 97 trials in 2015 to 2019, with a greater increase among RCTs of targeted therapy or immunotherapy, which increased from 0 trials in 2000 to 2004 to 36 trials in 2015 to 2019. The proportion of RCTs that were multicenter was higher in non-Asian regions than in Asian regions (50 of 71 RCTs [70.4%] vs 96 of 191 RCTs [50.3%]; P = .004). The analysis of research waste included 137 RCTs, of which 81 (59.1%) were published. Among published RCTs, 65 (80.2%) were judged to be adequately reported and 63 (77.8%) had avoidable design defects. Additionally, 119 RCTs (86.9%) had 1 or more features of research waste. Study settings that included blinding (odds ratio [OR], 0.56; 95% CI, 0.33-0.93; P = .03), a greater number of participants (ie, ≥200 participants; OR, 0.07; 95% CI, 0.01-0.51; P = .01), and external funding support (OR, 0.22; 95% CI, 0.08-0.60; P = .004) were associated with lower odds of research waste. Additionally, 35 RCTs (49.3%) were referenced in guidelines, and 18 RCTs (22.2%) had their prospective data reused. Conclusions and Relevance: To our knowledge, this study is the first to describe the characteristics of GC RCTs in the past 20 years, and it found a research waste burden, which may provide evidence for the development of rational RCTs and reduction of waste in the future.

Prevalence of control groups in cardiovascular clinical trials: An analysis of ClinicalTrials.gov from 2009 through 2019.

Clinical trials provide the foundational evidence that guide many patient-facing decisions; however, the therapeutic effect and safety of an intervention is best evaluated when compared to a control group. We used ClinicalTrials.gov to describe the proportion of registered Phase III and IV cardiovascular clinical trials that contain a control group from 2009 through 2019. Of 1,677 registered Phase III and IV cardiovascular clinical trials, 81.2% contain a control group, and the annual prevalence remained unchanged between 2009 and 2019.

On strategic choices faced by large pharmaceutical laboratories and their effect on innovation risk under fuzzy conditions.

OBJECTIVES: We develop a fuzzy evaluation model that provides managers at different responsibility levels in pharmaceutical laboratories with a rich picture of their innovation risk as well as that of competitors. This would help them take better strategic decisions around the management of their present and future portfolio of clinical trials in an uncertain environment. Through three structured fuzzy inference systems (FISs), the model evaluates the overall innovation risk of the laboratories by capturing the financial and pipeline sides of the risk. METHODS AND MATERIALS: Three FISs, based on the Mamdani model, determine the level of innovation risk of large pharmaceutical laboratories according to their strategic choices. Two subsystems measure different aspects of innovation risk while the third one builds on the results of the previous two. In all of them, both the partitions of the variables and the rules of the knowledge base are agreed through an innovative 2-tuple-based method. With the aid of experts, we have embedded knowledge into the FIS and later validated the model. RESULTS: In an empirical application of the proposed methodology, we evaluate a sample of 31 large pharmaceutical laboratories in the period 2008-2013. Depending on the relative weight of the two subsystems in the first layer (capturing the financial and the pipeline sides of innovation risk), we estimate the overall risk. Comparisons across laboratories are made and graphical surfaces are analyzed in order to interpret our results. We have also run regressions to better understand the implications of our results. CONCLUSIONS: The main contribution of this work is the development of an innovative fuzzy evaluation model that is useful for analyzing the innovation risk characteristics of large pharmaceutical laboratories given their strategic choices. The methodology is valid for carrying out a systematic analysis of the potential for developing new drugs over time and in a stable manner while managing the risks involved. We provide all the necessary tools and datasets to facilitate the replication of our system, which also may be easily applied to other settings.

A limited number of medicines pragmatic trials had potential for waived informed consent following the 2016 CIOMS ethical guidelines.

OBJECTIVES: European regulations do not allow modification or waiver of informed consent for medicines randomized controlled trials (RCTs) where the three 2016 Council for International Organizations of Medical Sciences (CIOMS) provisions are met (consent would be impractical or unfeasible, yet the trial would have high social value and pose no or minimal risk to participants). We aimed to identify whether any such trials of medicines were being conducted in Europe. STUDY DESIGN AND SETTING: This is a survey of all phase 4 "ongoing" RCTs on the EU clinical trial register between July 1, 2016 and June 30, 2018, to identify those with potentially high levels of pragmatism. Trials that were excluded were as follows: those conducted on rare diseases; conducted on healthy volunteers (except those assessing vaccines); masked (single-, double-blind) trials; single-center trials; those where one could expect to lead patients to prefer one intervention over the other; and miscellaneous reasons. The degree of pragmatism of the RCTs was self-assessed by trials' investigators by means of the PRECIS-2 tool. Investigators of those trials considered to be highly pragmatic assessed the fulfillment of the three CIOMS provisions. Seven patients assessed the social value of the RCTs. Finally, 33 members of 11 research ethics committees (RECs) assessed the social value of the trials and whether they posed no more than minimal risk to participants. Investigators, patients, and REC members assessed the fulfillment of the CIOMS provisions as "yes," "not sure" or "no." RESULTS: Of the 638 phase 4 trials, 420 were RCTs, and 21 of these (5%) were candidates to be pragmatic. Investigators of 15 of these 21 RCTs self-assessed their trial's degree of pragmatism: 14 were highly pragmatic. Of these 14, eight fulfilled the three CIOMS provisions. Assessments by patients and RECs were inconsistent for several trials. CONCLUSIONS: We found few low-risk participant-level pragmatic RCTs that could be suitable for modified or waived participants' informed consent. European regulators should consider amending the current regulation and encouraging the conduct of such trials.

Comparative efficacy and safety of dolutegravir relative to common core agents in treatment-naïve patients infected with HIV-1: a systematic review and network meta-analysis.

BACKGROUND: Network meta-analyses (NMAs) provide comparative treatment effects estimates in the absence of head-to-head randomized controlled trials (RCTs). This NMA compared the efficacy and safety of dolutegravir (DTG) with other recommended or commonly used core antiretroviral agents. METHODS: A systematic review identified phase 3/4 RCTs in treatment-naïve patients with HIV-1 receiving core agents: ritonavir-boosted protease inhibitors (PIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), or integrase strand inhibitors (INSTIs). Efficacy (virologic suppression [VS], CD4+ cell count change from baseline) and safety (adverse events [AEs], discontinuations, discontinuation due to AEs, lipid changes) were analyzed at Week 48 using Bayesian NMA methodology, which allowed calculation of probabilistic results. Subgroup analyses were conducted for VS (baseline viral load [VL] ≤/> 100,000copies/mL, ≤/> 500,000copies/mL; baseline CD4+ ≤/>200cells/µL). Results were adjusted for the nucleoside/nucleotide reverse transcriptase inhibitors (NRTI) combined with the core agent (except subgroup analyses). RESULTS: The NMA included 36 studies; 2 additional studies were included in subgroup analyses only. Odds of achieving VS with DTG were statistically superior to PIs (odds ratios [ORs] 1.78-2.59) and NNRTIs (ORs 1.51-1.86), and similar but numerically higher than other INSTIs. CD4+ count increase was significantly greater with DTG than PIs (difference: 23.63-31.47 cells/µL) and efavirenz (difference: 34.54 cells/µL), and similar to other core agents. INSTIs were more likely to result in patients achieving VS versus PIs (probability: 76-100%) and NNRTIs (probability: 50-100%), and a greater CD4+ count increase versus PIs (probability: 72-100%) and NNRTIs (probability: 60-100%). DTG was more likely to result in patients achieving VS (probability: 94-100%), and a greater CD4+ count increase (probability: 53-100%) versus other core agents, including INSTIs (probability: 94-97% and 53-93%, respectively). Safety outcomes with DTG were generally similar to other core agents. In patients with baseline VL > 100,000copies/mL or ≤ 200 CD4+cells/µL (18 studies), odds of achieving VS with DTG were superior or similar to other core agents. CONCLUSION: INSTI core agents had superior efficacy and similar safety to PIs and NNRTIs at Week 48 in treatment-naïve patients with HIV-1, with DTG being among the most efficacious, including in patients with baseline VL > 100,000copies/mL or ≤ 200 CD4+cells/µL, who can be difficult to treat.

Patient-level meta-analysis of efficacy and hypoglycaemia in people with type 2 diabetes initiating insulin glargine 100U/mL or neutral protamine Hagedorn insulin analysed according to concomitant oral antidiabetes therapy.

AIMS: Evaluate efficacy and hypoglycaemia according to concomitant oral antidiabetes drug (OAD) in people with type 2 diabetes initiating insulin glargine 100U/mL (Gla-100) or neutral protamine Hagedorn (NPH) insulin once daily. METHODS: Four studies (target fasting plasma glucose [FPG] ⩽100mg/dL [⩽5.6mmol/L]; duration ⩾24weeks) were included. Standardised data from 2091 subjects (Gla-100, n=1024; NPH insulin, n=1067) were analysed. Endpoints included glycated haemoglobin (HbA1c) and FPG change, glycaemic target achievement, hypoglycaemia, weight change, and insulin dose. RESULTS: Mean HbA1c and FPG reductions were similar with Gla-100 and NPH insulin regardless of concomitant OAD (P=0.184 and P=0.553, respectively) and similar proportions of subjects achieved HbA1c <7.0% (P=0.603). There was a trend for more subjects treated with Gla-100 achieving FPG ⩽100mg/dL versus NPH insulin (relative risk [RR] 1.09 [95% confidence interval (CI) 0.97-1.23]; P=0.135). Plasma glucose confirmed (<70mg/dL) overall and nocturnal hypoglycaemia incidences and rates were lower with Gla-100 versus NPH insulin (overall RR 0.93 [95% CI 0.87-1.00]; P=0.041; nocturnal RR 0.73 [95% CI 0.65-0.83]; P<0.001). After 24weeks, weight gain and insulin doses were higher with Gla-100 versus NPH insulin (2.7kg vs 2.3kg, P=0.009 and 0.42U/kg vs 0.39U/kg; P=0.003, respectively). Insulin doses were higher when either insulin was added to sulfonylurea alone. CONCLUSIONS: Pooled results from treat-to-target trials in insulin-naïve people with type 2 diabetes demonstrate a significantly lower overall and nocturnal hypoglycaemia risk across different plasma glucose definitions with Gla-100 versus NPH insulin at similar glycaemic control. OAD therapy co-administered with Gla-100 or NPH insulin impacts glycaemic control and overall nocturnal hypoglycaemia risk.

Overview of phase IV clinical trials for postmarket drug safety surveillance: a status report from the ClinicalTrials.gov registry.

OBJECTIVE: Phase IV trials are often used to investigate drug safety after approval. However, little is known about the characteristics of contemporary phase IV clinical trials and whether these studies are of sufficient quality to advance medical knowledge in pharmacovigilance. We aimed to determine the fundamental characteristics of phase IV clinical trials that evaluated drug safety using the ClinicalTrials.gov registry data. METHODS: A data set of 19 359 phase IV clinical studies registered in ClinicalTrials.gov was downloaded. The characteristics of the phase IV trials focusing on safety only were compared with those evaluating both safety and efficacy. We also compared the characteristics of the phase IV trials in three major therapeutic areas (cardiovascular diseases, mental health and oncology). Multivariable logistic regression was used to evaluate factors associated with the use of blinding and randomisation. RESULTS: A total of 4772 phase IV trials were identified, including 330 focusing on drug safety alone and 4392 evaluating both safety and efficacy. Most of the phase IV trials evaluating drug safety (75.9%) had enrolment <300 with 96.5% <3000. Among these trials, 8.2% were terminated or withdrawn. Factors associated with the use of blinding and randomisation included the intervention model, clinical specialty and lead sponsor. CONCLUSIONS: Phase IV trials evaluating drug safety in the ClinicalTrials.gov registry were dominated by small trials that might not have sufficient power to detect less common adverse events. An adequate sample size should be emphasised for phase IV trials with safety surveillance as main task.

The Add-Arm Design for Unimodal Response Curve with Unknown Mode.

In a classical drop-loser (or drop-arm) design, patients are randomized into all arms (doses) and at the interim analysis, inferior arms are dropped. Therefore, compared to the traditional dose-finding design, this adaptive design can reduce the sample size by not carrying over all doses to the end of the trial or dropping the losers earlier. However, all the doses have to be explored. For unimodal (including linear or umbrella) response curves, we proposed an effective dose-finding design that allows adding arms at the interim analysis. The trial design starts with two arms, depending on the response of the two arms and the unimodality assumption; we can decide which new arms to be added. This design does not require exploring all arms (doses) to find the best responsive dose; therefore, it can further reduce the sample size from the drop-loser design by as much as 10-20%.

Methods for observational post-licensure medical product safety surveillance.

Post-licensure medical product safety surveillance is important for detecting adverse events potentially not identified pre-licensure. Historically, post-licensure safety monitoring has been accomplished using passive reporting systems and by conducting formal Phase IV randomized trials or large epidemiological studies, also known as safety surveillance or pharmacovigilance studies. However, crucial gaps in the safety evidence base provided by these approaches have led to high profile product withdrawals and growing public concern about unknown health risks associated with licensed products. To address the limitations of existing surveillance systems and to facilitate more accurate and rapid detection of safety problems, new systems involving active surveillance of large, population-based cohorts using observational health care databases are being developed. In this article, we review common statistical methods that have been employed previously for post-licensure safety monitoring, including data mining and sequential hypothesis testing, and assess which methods may be promising for potential use within this newly proposed prospective observational cohort monitoring framework. We discuss gaps in existing approaches and identify areas where methodological development is needed to improve the success of safety surveillance efforts in this setting.

Work productivity and healthcare resource utilization outcomes for patients on etanercept for moderate-to-severe plaque psoriasis: results from a 1-year, multicentre, open-label, single-arm study in a clinical setting.

BACKGROUND: Data investigating the effect of etanercept on work productivity and healthcare resource utilization in Canadian patients in a clinical setting is limited. OBJECTIVE: The aim of the study was to describe work productivity and healthcare resource utilization in patients with psoriasis prescribed etanercept. METHODS: A 12-month, phase IV, non-randomized, multicentre, open-label, single-arm prospective trial of patients with moderate-to-severe plaque psoriasis was conducted between March 2006 and July 2009 in 37 community dermatology practice sites across Canada. A total of 246 patients were enrolled. Major eligibility criteria: ≥18 years of age; diagnosis of moderate-to-severe plaque psoriasis at baseline (Physician Global Assessment [PGA] ≥3, scale 0-5); able to start etanercept therapy as per product monograph. Patients received etanercept (Enbrel(®)) 50 mg subcutaneously twice weekly for 3 months, then 50 mg once weekly for 9 months. Outcomes were measured by average change and average percent change from baseline at months 3, 6, 9 and 12 on the Work Productivity and Activity Impairment (WPAI) and Healthcare Resource Utilization (HRU) questionnaires. RESULTS: The mean degree of impairment while working ± standard deviation (SD) in the total population decreased from 22.7% ± 23.2 at baseline to 6.6% ± 14 after 3 months of treatment (p < 0.0001). From baseline to 3 months, overall work impairment ± SD decreased from 23.7% ± 23.7 to 8.3% ± 16.5 (p < 0.0001) and mean activity impairment outside the workplace decreased from 31.4% ± 26.4 to 12.9% ± 22.4 (p < 0.0001). All these improvements were sustained to month 12. Other variables that decreased on average from baseline to month 3, sustained to month 12, included physician office visits (2.3/month ± 3.5 at baseline to 0.6/month ± 1.0 at month 3; p < 0.0002), hours of assistance required of family and friends to assist with psoriasis (1.1 hours/week ± 2.6 at baseline to 0.3 hours/week ± 1.5 at month 3; p = 0.0002) and amount of time spent on activities to manage psoriasis (5.5 hours/week ± 6.2 at baseline to 1.9 hours/week ± 3.7 at month 3; p < 0.0001). Also, the amount of out-of-pocket expenses to manage psoriasis decreased from $Can94.9/month ± 331.6 at baseline to $Can35.7 ± 69.1 at month 12 (p = 0.0153). CONCLUSIONS: Use of etanercept in Canadian patients in a clinical practice setting correlated with improvement in work productivity and reduced HRU after 3 months of treatment, and improvement was sustained up to 12 months.

[Patients' perspective and economic variables as objectives in clinical trials: added value to clinical parameters]. / Perspectiva de los pacientes y variables económicas como objetivo en los ensayos clínicos, valores añadidos a los parámetros clínicos.

OBJECTIVE: Patient-reported outcome (PRO) measures complement traditional biomedical outcome measures. The purpose of this study was to evaluate the use of PRO measures including health-related quality of life (HRQoL) questionnaires as a measurement of efficacy and the frequency of inclusion of economic variables related to direct and indirect costs in the design of clinical trials and phase IV observational studies. Moreover, for the trials quality score were measured, and if there were any relationship between the quality study design score and the PRO inclusion. MATERIAL AND METHODS: Retrospective observational study of the clinical trials and phase IV observational studies approved by a Clinical Research Ethics Committee (2008-2010). We gathered data concerning general aspects including medical specialty, pathology, methodological quality based on Jadad scale (0-5), inclusion of PRO and economic variables. For clinical trials including HRQoL measurements, we analysed the type of questionnaire in use. Where there were no HRQoL measurements, we analysed if their inclusion would have been proper or not. RESULTS: A total of 70 protocols (59 CTs and 11 phase IV observational studies) were analysed; 37 (52.8%) included PRO measures, and 3 protocols (4.3%) used them as a primary endpoint. Data analysis by therapeutic area showed that PRO measures were most commonly studied in the fields of endocrinology, neurology, digestive diseases, and cardiology. The average quality score for the trials was 2.8. The trials with more PRO inclusion in their end points had a significantly higher quality score. Only 13 (22%) clinical trials and 2 (18.2%) phase IV observational studies included economic variables. CONCLUSIONS: The emergence of economic variables in clinical trials and phase IV observational studies evaluated was low, however, more than half of the revised protocols have included PRO measures, reflecting the importance of these parameters in the assessment of the effectiveness of drug treatments, although its use is still not systematic.

Pitavastatin: clinical effects from the LIVES Study.

Although clinical trials provide useful information on drug safety and efficacy, results do not always reflect those observed in the real world. The Japanese long-term prospective post-marketing surveillance LIVALO Effectiveness and Safety (LIVES) Study was designed to assess the efficacy and safety of pitavastatin in clinical practice in ~20,000 patients. After 104 weeks, pitavastatin was associated with significant reductions in low-density lipoprotein-cholesterol (LDL-C) (29.1%) that largely occurred within 4 weeks of treatment initiation. In patients with abnormal triglyceride (TG) and high-density lipoprotein-cholesterol (HDL-C) levels at baseline, pitavastatin reduced TG and increased HDL-C by 22.7% and 19.9%, respectively. Overall, 88.2% of the primary prevention low-risk patients attained their Japan Atherosclerosis Society LDL-C target, compared with 82.7% of intermediate-risk patients, 66.5% of high-risk patients and 50.3% of secondary prevention patients. Only 10.4% of pitavastatin-treated patients experienced adverse events (AEs), of which approximately 84% were mild and around 1% was severe. Increases in blood creatine phosphokinase (2.7%), alanine aminotransferase (1.8%), myalgia (1.1%), aspartate aminotransferase (1.5%) and gamma-glutamyltransferase (1.0%) were the most common AEs and only 7.4% of patients discontinued pitavastatin due to AEs. Regression analysis demonstrated that age was not a significant factor for the incidence of any AE or myopathy-associated events. A subanalysis of initial LIVES data focussing on the effects of pitavastatin on HDL-C levels showed that HDL-C was elevated by 5.9% in all patients and by 24.6% in those with low (

Pitavastatin: novel effects on lipid parameters.

Atherogenic dyslipidemia is characterised by high levels of triglycerides, low levels of high-density lipoprotein-cholesterol (HDL-C), and moderate to marked elevations in low-density lipoprotein-cholesterol (LDL-C) concentrations; such dyslipidemia is further characterised by high apolipoprotein B (apoB): apolipoprotein A1 (apoA1) ratios. Numerous clinical trials have demonstrated that statins are effective in lowering LDL-C and reducing cardiovascular (CV) risk in people with dyslipidemia. However, the most effective treatments should target all of the key atherogenic features, rather than LDL-C alone. Pitavastatin is a new member of the statin class whose distinct pharmacological features translate into a broad spectrum of action on both apoB-containing and apoA1-containing lipoprotein components of the atherogenic lipid profile. The efficacy and safety of this statin has been demonstrated by a large clinical development programme conducted both in Japanese and Caucasian populations. Phase III and IV studies in a wide range of patients with primary hypercholesterolemia or combined dyslipidemia showed that 12 weeks' treatment with pitavastatin l-4 mg was well tolerated, significantly improved lipid profiles (including LDL-C, TG, and HDL-C levels) and increased the EAS-/NCEP ATP Ill-recommended LDL-C target attainment rate to a similar or greater degree as comparable doses of atorvastatin, simvastatin, or pravastatin. Results were similar across all patient groups and were generally sustained after 52 weeks of treatment. However, whereas the effects of atorvastatin and simvastatin on HDL-C levels remained constant over the long term, pitavastatin-treated patients experienced progressive and maintained elevations in HDL-C, ultimately increasing by up to 14.3% vs. initial baseline. In this context, it is significant that the in vitro studies of Yamashita et al. [J Atheroscler Thromb 2010;17:436-51] have shown pitavastatin to be distinguished by its potent stimulation of apoA1 production in hepatocyte-like cells. These findings suggest that pitavastatin may be highly efficacious in raising levels of lipid-poor apoA1 particles, which are known to be highly active in ABCA1-mediated cellular cholesterol efflux, an observation which is pertinent to the excessive accumulation of cholesterol in macrophage foam cells of the atherosclerotic plaque. Indeed, the intravascular remodelling and maturation of lipid-poor apoA1 particles is known to drive flux of apoA1, cholesterol and phospholipid through the HDL pathway. It is equally relevant that pitavastatin therapy has been shown to be efficacious in markedly reducing coronary atheroma volume in acute coronary syndrome patients in the JAPAN-ACS trial, a therapeutic effect which may be linked to its impact on apoA1/HDL metabolism and function. Overall, Phase III and IV studies demonstrate that pitavastatin 1-4 mg is well tolerated, attenuates the atherogenic lipid profile and increases LDL-C target attainment rates with a similar or greater efficacy to comparable doses of atorvastatin, simvastatin and pravastatin. Furthermore, pitavastatin may be particularly beneficial in high-risk patients with elevated concentrations of TG-rich lipoproteins and low levels of HDL-C, and in whom the atheroprotective function of HDL particles is typically defective; significantly, such patients typically exhibit persistent, residual cardiometabolic risk even when LDL-C is at goal. In this context, it is relevant that such patient groups cover a wide spectrum of metabolic diseases, including metabolic syndrome, type 2 diabetes, coronary disease, familial and non-familial forms of hypercholesterolemia, auto-immune diseases such as rheumatoid arthritis and lupus, renal disease and some forms of hepatic insufficiency.

Semiparametric bayesian testing procedure for noninferiority trials with binary endpoints.

A semiparametric testing approach based on the Bayes factor is developed for non-inferiority trials with binary endpoints. The proposed method is shown to work for a broad class of hypotheses by accommodating a variety of dissimilarity measures between two binomial parameters. Two of the unique features of the proposed testing procedure include: (i) construction of a flexible class of conjugate priors using a mixture of beta densities to maintain approximate equality of prior probabilities of the competing hypotheses; and (ii) automatic determination of the cutoff value of the Bayes factor to facilitate the decision making process. In contrast to the use of Jeffreys's rule of thumb, two forms of total weighted average error criteria are used to determine the cutoff value. Through several simulation studies it is demonstrated that the proposed Bayesian procedure has competitive frequentist properties of controlling type I error as compared to the default frequentist test and meanwhile the proposed criterion improves the statistical power, especially in small samples. The method is further illustrated using the data from a streptococcal pharyngitis clinical trial.

Robust extraction of covariate information to improve estimation efficiency in randomized trials.

In randomized trials, investigators typically rely upon an unadjusted estimate of the mean outcome within each treatment arm to draw causal inferences. Statisticians have underscored the gain in efficiency that can be achieved from covariate adjustment in randomized trials with a focus on problems involving linear models. Despite recent theoretical advances, there has been a reluctance to adjust for covariates based on two primary reasons: (i) covariate-adjusted estimates based on conditional logistic regression models have been shown to be less precise and (ii) concern over the opportunity to manipulate the model selection process for covariate adjustments to obtain favorable results. In this paper, we address these two issues and summarize recent theoretical results on which is based a proposed general methodology for covariate adjustment under the framework of targeted maximum likelihood estimation in trials with two arms where the probability of treatment is 50%. The proposed methodology provides an estimate of the true causal parameter of interest representing the population-level treatment effect. It is compared with the estimates based on conditional logistic modeling, which only provide estimates of subgroup-level treatment effects rather than marginal (unconditional) treatment effects. We provide a clear criterion for determining whether a gain in efficiency can be achieved with covariate adjustment over the unadjusted method. We illustrate our strategy using a resampled clinical trial dataset from a placebo controlled phase 4 study. Results demonstrate that gains in efficiency can be achieved even with binary outcomes through covariate adjustment leading to increased statistical power.

The potential role of appetite in predicting weight changes during treatment with olanzapine.

BACKGROUND: Clinically significant weight gain has been reported during treatment with atypical antipsychotics. It has been suggested that weight changes in patients treated with olanzapine may be associated with increased appetite. METHODS: Data were used from adult patients for whom both appetite and weight data were available from 4 prospective, 12- to 24-week clinical trials. Patients' appetites were assessed with Eating Behavior Assessment (EBA, Study 1), Platypus Appetite Rating Scale (PARS, Study 2), Eating Inventory (EI, Study 3), Food Craving Inventory (FCI, Study 3), and Eating Attitude Scale (EAS, Study 4). RESULTS: In Studies 1 (EBA) and 4 (EAS), patients who reported overall score increases on appetite scales, indicating an increase in appetite, experienced the greatest overall weight gains. However, in Studies 2 (PARS) and 3 (EI, FCI), patients who reported overall score increases on appetite scales did not experience greater weight changes than patients not reporting score increases. Early weight changes (2-4 weeks) were more positively correlated with overall weight changes than early or overall score changes on any utilized appetite assessment scale. No additional information was gained by adding early appetite change to early weight change in correlation to overall weight change. CONCLUSIONS: Early weight changes may be a more useful predictor for long-term weight changes than early score changes on appetite assessment scales. CLINICAL TRIALS REGISTRATION: This report represents secondary analyses of 4 clinical studies. Studies 1, 2, and 3 were registered at http://clinicaltrials.gov/ct2/home, under NCT00190749, NCT00303602, and NCT00401973, respectively. Study 4 predates the registration requirements for observational studies that are not classified as category 1 observational studies.

Estudios postautorización de tipo observacional en España: impacto de la regulación del año 2002 / Studies postauthorization of type observacional in Spain: impact of the regulation of the year 2002

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The effect of the European Clinical Trials Directive on published drug research in anaesthesia.

The clinical indications for anaesthetic drugs are developed through peer-reviewed publication of clinical trials. We performed a bibliometric analysis of all human research papers reported in nine general anaesthesia journals over 6 years (n = 6489), to determine any effects of the 2004 European Clinical Trials Directive on reported drug research in anaesthesia originating from Europe and the United Kingdom. We found 89% studies involved patients and 11% volunteers. Of 3234 (50%) drug studies, 96% were phase IV (post-marketing) trials. Worldwide, the number of research papers fell by 3.6% (p < 0.004) in the 3 years following introduction of the European Clinical Trials Directive (5% Europe, 18% United Kingdom), and drug research papers fell by 12% (p < 0.001; 15% Europe, 29% United Kingdom). The introduction of the Clinical Trials Directive has therefore coincided with a decline in European drug research, particularly that originating from the United Kingdom. We suggest a number of measures researchers could take in response, and we propose a simplification of the application process for phase IV clinical trials, emphasising patient risk assessment.

A behavioral Bayes method to determine the sample size of a clinical trial considering efficacy and safety.

It is necessary for the calculation of sample size to achieve the best balance between the cost of a clinical trial and the possible benefits from a new treatment. Gittins and Pezeshk developed an innovative (behavioral Bayes) approach, which assumes that the number of users is an increasing function of the difference in performance between the new treatment and the standard treatment. The better a new treatment, the more the number of patients who want to switch to it. The optimal sample size is calculated in this framework. This BeBay approach takes account of three decision-makers, a pharmaceutical company, the health authority and medical advisers. Kikuchi, Pezeshk and Gittins generalized this approach by introducing a logistic benefit function, and by extending to the more usual unpaired case, and with unknown variance. The expected net benefit in this model is based on the efficacy of the new drug but does not take account of the incidence of adverse reactions. The present paper extends the model to include the costs of treating adverse reactions and focuses on societal cost-effectiveness as the criterion for determining sample size. The main application is likely to be to phase III clinical trials, for which the primary outcome is to compare the costs and benefits of a new drug with a standard drug in relation to national health-care.