Early termination of cardiovascular trials as a consequence of poor accrual: analysis of ClinicalTrials.gov 2006-2015

Predictors of premature termination of cardiac surgery trials: insights from the Clinicaltrial.gov database

OBJECTIVES

Clinical trials that are terminated prematurely may generate incomplete and potentially biased data and the reasons for premature trials termination are poorly understood. Our objective was to describe the incidence of premature trial termination and identify factors associated with it.

METHODS

We performed a systematic search on ClinicalTrials.gov to identify all cardiac surgery trials from 1991 to 2023. Trials that were terminated prematurely were identified. Factors independently associated with premature termination were identified using multivariable logistic regression analysis.

RESULTS

A total of 746 clinical trials were included; of them 577 were completed and 169 (22.6%) were terminated prematurely. Most of the trials originated from North America [294 (39.4%)], Europe [264 (35.4%)] or Asia [141 (18.9%)]. Fourteen of the trials terminated prematurely (8.3%) were phase 1, 75 (44.4%) phase 2, 49 (29.0%) phase 3 and 31 (18.3%) phase 4. Fifty (29.6%) trials were terminated because of slow recruitment, 20 (11.8%) because of sponsor decision and 12 (7.1%) because of lack of funding. Left ventricular assist device trials [odds ratio (OR) 3.65, 95% confidence interval (CI) (1.65-8.00) P = 0.001], valve surgery trials [OR 4.30, 95% CI (2.33-8.00) P < 0.001], aortic surgery trials [OR 2.86 95% CI (1.22-6.43) P = 0.012], phase 2 [OR 3.02, 95% CI (1.31-7.93) P = 0.015] and phase 4 trials [OR 3.62, 95% CI (1.43-10.23) P = 0.010] were at higher risk of premature termination while trials performed in Asia [OR 0.18, 95% CI (0.07-0.39) P ≤ 0.001] and Europe [OR 0.49, 95% CI (0.30-0.80) P = 0.004] were less likely to be terminated prematurely.

CONCLUSIONS

Slow recruitment is the most common reason for premature termination of cardiac surgery trials. Trials on left ventricular assist device, valve surgery, aortic surgery, phase 2 trials and phase 4 trials are more likely to be terminated, while trials conducted in Asia and Europe are less likely to be terminated prematurely.

Publication Bias in Upper Gastrointestinal Oncology Clinical Trials

PURPOSE

Evidence-based medicine requires evaluation of the medical literature to guide clinical reasoning and treatment recommendations. The presence of publication bias towards exclusion of non-statistically significant clinical trials may be leading to an incomplete evaluation of the literature and cause potentially incomplete guidance for patients. We aimed to compare publication rates and impact of publications of positive and negative outcome clinical trials.

METHODS

We queried the US National Library of Medicine Clinical Trials database identifying clinical trials with reported results on the topics of pancreatic, liver, and gastric cancer. A "positive" trial was defined as having a statistically significant difference between the treatment arms, while a "negative" did not. Data collected included termination cause, intervention, funding type, publication rates, and journal characteristics.

RESULTS

In total, 535 clinical trials were examined, across all pathologies clinical trials with significant findings for the primary outcome were published at a higher rate (99%) compared to those with non-significant findings (77%) (p < 0.01). Significantly, more studies with significant findings reached at least 80% of their estimated enrollment goal versus non-significant studies, 72% and 53% respectively (p < 0.01). Three of four metrics for impact of publication showed no difference between significant and non-significant studies once they reached publication.

CONCLUSION

These findings suggest that clinical trials of three of the most common upper gastrointestinal malignancies have a publication bias towards studies with significant primary outcome findings. This study has implications to the way evidence-based medicine is practiced as the medical literature appears to be failing to capture important data for consideration of clinical decision making.

Leveraging electronic health records to streamline the conduct of cardiovascular clinical trials

Conventional randomized controlled trials (RCTs) can be expensive, time intensive, and complex to conduct. Trial recruitment, participation, and data collection can burden participants and research personnel. In the past two decades, there have been rapid technological advances and an exponential growth in digitized healthcare data. Embedding RCTs, including cardiovascular outcome trials, into electronic health record systems or registries may streamline screening, consent, randomization, follow-up visits, and outcome adjudication. Moreover, wearable sensors (i.e. health and fitness trackers) provide an opportunity to collect data on cardiovascular health and risk factors in unprecedented detail and scale, while growing internet connectivity supports the collection of patient-reported outcomes. There is a pressing need to develop robust mechanisms that facilitate data capture from diverse databases and guidance to standardize data definitions. Importantly, the data collection infrastructure should be reusable to support multiple cardiovascular RCTs over time. Systems, processes, and policies will need to have sufficient flexibility to allow interoperability between different sources of data acquisition. Clinical research guidelines, ethics oversight, and regulatory requirements also need to evolve. This review highlights recent progress towards the use of routinely generated data to conduct RCTs and discusses potential solutions for ongoing barriers. There is a particular focus on methods to utilize routinely generated data for trials while complying with regional data protection laws. The discussion is supported with examples of cardiovascular outcome trials that have successfully leveraged the electronic health record, web-enabled devices or administrative databases to conduct randomized trials.

Early Termination of Oncology Clinical Trials in the United States

PURPOSE

The aim of this study was to evaluate the rate of early trial discontinuation of oncology trials and reasons for early termination, to assess potential trends in rates of oncology trial termination, and to perform a comprehensive analysis of predictors of early termination. This study intends to inform efforts in improving efficiency of the oncology clinical trial enterprise.

METHODS

We conducted a cross-sectional study of interventional cancer clinical trials registered in ClinicalTrials.gov database from September 27, 2007 to June 30, 2015, with at least one site listed in the United States. We evaluated predictors of early trial termination using Fisher exact or χ² tests and logistic regression.

RESULTS

Of 8687 trials, 22.74% (n = 1975) were terminated trials. Rates of early trial termination appeared stable over the study. Statistically significant univariate predictors of early termination for any reason include cancer category, phase, funding source, location, and age. In multivariable analysis, trials spanning multiple cancer categories and international trials were less likely to terminate early whereas phase 2 trials and trials funded by academia/foundation were more likely to terminate early. The most common reason for early termination was "Other, Multiple Reasons, or Unknown" (36.9%), followed by accrual issues (34.5%). In multivariate analysis among all terminated trials, supportive care trials, phase 2 trials, and non-industry funded trials had significantly higher odds of trial discontinuation specifically due to poor accrual.

CONCLUSION

In this national sample of cancer clinical trials, early trial discontinuation was common. Many factors influenced early trial termination with poor accrual being a common reason. Specific trial features are associated with differential likelihood of early trial termination for any reason and for early trial termination due to poor accrual.

Recruitment across two decades of NIH-funded Alzheimer's disease clinical trials

BACKGROUND

Timely accrual of a representative sample is a key factor in whether Alzheimer's disease (AD) clinical trials successfully answer the scientific questions under study. Studies in other fields have observed that, over time, recruitment to trials has become increasingly reliant on larger numbers of sites, with declines in the average per-site recruitment rate. Here, we examined the trends in recruitment over a 20-year period of NIH-funded AD clinical trials conducted by the Alzheimer's Disease Cooperative Study (ADCS), a temporally consistent network of sites devoted to interventional research.

METHODS

We performed retrospective analyses of eleven ADCS randomized clinical trials. To examine the recruitment planning, we calculated the expected number of participants to be enrolled per site for each trial. To examine the actual trial recruitment rates, we quantified the number of participants enrolled per site per month.

RESULTS

No effects of time were observed on recruitment planning or overall recruitment rates across trials. No trial achieved an overall recruitment rate greater than one subject per site per month. We observed the fastest recruitment rates in trials with no competition and the slowest in trials that overlapped in time. The highest recruitment rates were consistently seen early within trials and declined over the course of studies.

CONCLUSIONS

Trial recruitment projections should plan for fewer than one participant randomized per site per month and consider the number of other AD trials being conducted concurrently.

A census of clinical trials conducted under the U.S. exception from informed consent rule

BACKGROUND

The exception from informed consent (EFIC) rule was adopted in 1996, permitting waiver of informed consent for certain emergency research, including trials funded by the U.S. government. The rule requires prospective consent from patients or their legally authorized representative(s) (LAR) if practicable. For those enrolled without consent, the patient or their LAR must be given an opportunity to opt out from continued participation at the earliest opportunity. We sought to census the trials conducted under the EFIC rule to facilitate research to better understand how the rule is being used.

METHODS

We conducted a multipronged search to identify all trials conducted under the EFIC rule, drawing on reviews, database searches, examination of the FDA's docket, posting an inquiry on the institutional review board forum, and email requests to lead authors of all published EFIC trials and related review articles. We describe the trials, when they were started and completed, and whether they were terminated early.

RESULTS

We identified a total of 110 trials as of the end of April 2022: 78 complete, 13 recruiting, seven registered on clinicaltrials.gov but not yet recruiting, five trials that were abandoned before enrolling any subjects, and seven trials in early planning. Nine of the 78 completed trials were pilot or feasibility trials. Of 69 completed full trials, 30 (43.5%) were terminated early. The most common reason for early termination was futility (15 trials, 25.0%) followed by poor recruitment (10 trials, 14.5%). The rate of conduct of trials has been remarkably constant since 2001, with roughly 18 trials started in each 5-year period.

CONCLUSIONS

We have compiled a census of trials conducted under the U.S. FDA's EFIC rule, the availability of which we hope will stimulate further in-depth data collection and analysis of this set of trials.

Ensuring the Scientific Value and Feasibility of Clinical Trials: A Qualitative Interview Study

BACKGROUND

Ethical and scientific principles require that clinical trials address an important question and have the resources needed to complete the study. However, there are no clear standards for review that would ensure that these principles are upheld.

METHODS

We conducted semi-structured interviews with a convenience sample of nineteen experts in clinical trial design, conduct, and/or oversight to elucidate current practice and identify areas of need with respect to ensuring the scientific value and feasibility of clinical trials prior to initiation and while ongoing. We used a priori and grounded theory to analyze the data and constant comparative method to induce higher order themes.

RESULTS

Interviewees perceived determination of scientific value as the responsibility of the investigator and, secondarily, other parties who review or oversee research. Interviewees reported that ongoing trials are rarely reevaluated due to emerging evidence from external sources, evaluation is complex, and there would be value in the development of standards for monitoring and evaluating evidence systematically. Investigators, IRBs, and/or data monitoring committees (DMCs) could undertake these responsibilities. Feasibility assessments are performed but are typically inadequate; potential solutions are unclear.

CONCLUSIONS

There are three domains where current approaches are suboptimal and in which further guidance is needed. First, who has the responsibility for conducting scientific review, whether it be the investigator, IRB, and/or DMC is often unclear. Second, the standards for scientific review (e.g., appropriate search terms, data sources, and analytic plan) should be defined. Third, guidance is needed on the evaluation of ongoing studies in light of potentially new and evolving evidence, with particular reference to evidence from outside the trial itself.

Early Termination of Acute Stroke Randomized Controlled Trials Published Between 2013 and 2020: A Systematic Review

BACKGROUND

Termination of a clinical trial before the maximum planned sample size is accrued can occur for multiple valid reasons but has implications for the interpretation of results. We undertook a systematic review of contemporary acute stroke trials to document the prevalence of and reasons for early termination.

METHODS

We searched MEDLINE for randomized controlled trials of acute stroke therapies published between 2013 and 2020 in 9 major clinical journals. Manuscripts describing the primary results of phase 2 and phase 3 trials of acute stroke care were included. Data on study characteristics and adherence to CONSORT reporting guidelines were abstracted and summarized using descriptive statistics. Where feasible, we compared treatment effect sizes between trials terminated early and those not terminated early.

RESULTS

Of 96 randomized controlled trials, 39 (41%) were terminated early, 84 (88%) had a data and safety monitoring board, and 57 (59%) reported a prespecified statistical stopping rule. Among the 39 trials terminated early, 10 were discontinued for benefit, 10 due to logistical issues, 8 for futility, 6 because of newly available evidence, 1 for harm, and 4 for other or a combination of reasons. The median percentage of the maximum planned sample size accrued among trials terminated early was 63% (range, 8%-89%). Only 55% of trials (53 of 96) reported whether interim efficacy analyses were conducted, as recommended by the CONSORT guidelines. When 10 endovascular therapy trials were compared according to early termination status, the effect sizes of trials terminated early for benefit were only modestly larger than those not terminated early.

CONCLUSIONS

The high prevalence of early termination in combination with the wide variety of reasons underscores the necessity of meticulous trial planning and adherence to methodological and reporting guidelines for early termination. Registration: URL: https://www.crd.york.ac.uk/prospero/; Unique identifier: CRD42019128727.

Target and actual sample sizes for studies from two trial registries from 1999 to 2020: an observational study

Objectives

To investigate differences between target and actual sample sizes, and what study characteristics were associated with sample sizes.

Design

Observational study.

Setting

The large trial registries of clinicaltrials.gov (starting in 1999) and ANZCTR (starting in 2005) through to 2021.

Participants

Over 280 000 interventional studies excluding studies that were withheld, terminated for safety reasons or were expanded access.

Main outcome measures

The actual and target sample sizes, and the within-study ratio of the actual to target sample size.

Results

Most studies were small: the median actual sample sizes in the two databases were 60 and 52. There was a decrease over time in the target sample size of 9%–10% per 5 years, and a larger decrease of 18%–21% per 5 years for the actual sample size. The actual-to-target sample size ratio was 4.1% lower per 5 years, meaning more studies (on average) failed to hit their target sample size.

Conclusion

Registered studies are more often under-recruited than over-recruited and worryingly both target and actual sample sizes appear to have decreased over time, as has the within-study gap between the target and actual sample size. Declining sample sizes and ongoing concerns about underpowered studies mean more research is needed into barriers and facilitators for improving recruitment and accessing data.

A systematic review and meta-analysis of enrollment into ARDS and sepsis trials published between 2009 and 2019 in major journals

BACKGROUND

Enrollment problems are common among randomized controlled trials conducted in the ICU. However, little is known about actual trial enrollment rates and influential factors. We set out to determine the overall enrollment rate in recent randomized controlled trials (RCTs) of patients with acute respiratory distress syndrome (ARDS), acute lung injury (ALI), or sepsis, and which factors influenced enrollment rate.

METHODS

We conducted a systematic review by searching Pubmed using predefined terms for ARDS/ALI and sepsis to identify individually RCTs published among the seven highest impact general medicine and seven highest impact critical care journals between 2009 and 2019. Cluster randomized trials were excluded. Data were extracted by two independent reviewers using an electronic database management system. We conducted a random-effects meta-analysis of the eligible trials for the primary outcome of enrollment rate by time and site.

RESULTS

Out of 457 articles identified, 94 trials met inclusion criteria. Trials most commonly evaluated pharmaceutical interventions (53%), were non-industry funded (78%), and required prospective informed consent (81%). The overall mean enrollment rate was 0.83 (95% confidence interval: 0.57-1.21) participants per month per site. Enrollment in ARDS/ALI and sepsis trials were 0.48 (95% CI 0.32-0.70) and 0.98 (95% CI 0.62-1.56) respectively. The enrollment rate was significantly higher for single-center trials (4.86; 95% CI 2.49-9.51) than multicenter trials (0.52; 95% CI 0.41-0.66). Of the 36 trials that enrolled < 95% of the target sample size, 8 (22%) reported slow enrollment as the reason.

CONCLUSIONS

In this systematic review and meta-analysis, recent ARDS/ALI and sepsis clinical trials had an overall enrollment rate of less than 1 participant per site per month. Novel approaches to improve critical care trial enrollment efficiency are needed to facilitate the translation of best evidence into practice.

General characteristics and reasons for the discontinuation of drug clinical trials in mainland China

Background

Although discontinuation is common in clinical trials, no study has been conducted to analyse the current situation and reasons for the suspension or discontinuation of drug clinical trials in China. This study aims to analyse the general characteristics and reasons for the discontinuation of registered clinical trials in mainland China and to identify the associated factors.

Methods

We conducted a cross-sectional observational study of discontinued trials registered in the Drug Trial Registration and Information Publication Platform before March 31, 2020. All trials with a status of terminated or stopped recorded in the platform were classified as discontinued trials and included in the analysis. The basic characteristics of the discontinued trials were recorded, reasons for trial discontinuation were recorded and divided into 4 categories as drug development strategy, trial planning, trial conduct and studied drug. Pearson’s chi-square test and fisher’s exact test were used to compare the differences in reasons for discontinuation between neoplasm trials and non-neoplasm trials, and to examine the associations of trial characteristics with different reasons related to trials discontinuation.

Results

Three hundred twelve discontinued trials were included in this study. The studied drugs were mainly chemical drugs [229 (73.4%)], and indications of the studied drugs were mainly neoplasms [77 (24.7%)]. Geographical location of the discontinued trials were mostly in northern [114 (36.5%)] and eastern [96 (30.8%)] China. Study type of the included trials was mainly bioequivalence studies [97 (31.1%)]. The most common reason for trial discontinuation was commercial or strategic decision [84 (26.9%)], followed by futility/lack of efficacy [70 (22.4%)]. The number of trial centers, sample size and whether participants had been enrolled were significantly associated with trial discontinuation (P <  0.05). Multiple center trials showed a higher rate of trial discontinuation due to trial conduct related reasons than single center trials (P <  0.05), trials with sample size > 500 showed a higher rate of trial discontinuation due to studied drug related reasons (P < 0.05), and trials enrolled participants showed a lower rate of trial discontinuation due to commercial or strategic decision and a higher rate of trial discontinuation due to studied drug related reasons than trials without enrolled participants (P < 0.05). Besides, neoplasm trials showed a higher rate of trial discontinuation due to poor recruitment and safety comparing with non-neoplasm trials (P < 0.05).

Conclusions

Trial discontinuation in China mainly occurred because of commercial or strategic decision and futility/lack of efficacy of the studied drug. Clinical trials with multiple centers and a large sample size may more likely be discontinued due to trial conduct related reasons such as good clinical practice. Discontinuation due to drug safety and lack of efficacy in multiple center trials with a large sample size deserves more attention to avoid resources wastes. Full communication with regulatory authorities such as Center for Drug Evaluation and research institutes to develop a feasible protocol is important for sponsors to avoid trial discontinuation due to protocol issues.

Handling Poor Accrual in Pediatric Trials: A Simulation Study Using a Bayesian Approach

In the conduction of trials, a common situation is related to potential difficulties in recruiting the planned sample size as provided by the study design. A Bayesian analysis of such trials might provide a framework to combine prior evidence with current evidence, and it is an accepted approach by regulatory agencies. However, especially for small trials, the Bayesian inference may be severely conditioned by the prior choices. The Renal Scarring Urinary Infection (RESCUE) trial, a pediatric trial that was a candidate for early termination due to underrecruitment, served as a motivating example to investigate the effects of the prior choices on small trial inference. The trial outcomes were simulated by assuming 50 scenarios combining different sample sizes and true absolute risk reduction (ARR). The simulated data were analyzed via the Bayesian approach using 0%, 50%, and 100% discounting factors on the beta power prior. An informative inference (0% discounting) on small samples could generate data-insensitive results. Instead, the 50% discounting factor ensured that the probability of confirming the trial outcome was higher than 80%, but only for an ARR higher than 0.17. A suitable option to maintain data relevant to the trial inference is to define a discounting factor based on the prior parameters. Nevertheless, a sensitivity analysis of the prior choices is highly recommended.

Obstacles to the reuse of study metadata in ClinicalTrials.gov

Metadata that are structured using principled schemas and that use terms from ontologies are essential to making biomedical data findable and reusable for downstream analyses. The largest source of metadata that describes the experimental protocol, funding, and scientific leadership of clinical studies is ClinicalTrials.gov. We evaluated whether values in 302,091 trial records adhere to expected data types and use terms from biomedical ontologies, whether records contain fields required by government regulations, and whether structured elements could replace free-text elements. Contact information, outcome measures, and study design are frequently missing or underspecified. Important fields for search, such as condition and intervention, are not restricted to ontologies, and almost half of the conditions are not denoted by MeSH terms, as recommended. Eligibility criteria are stored as semi-structured free text. Enforcing the presence of all required elements, requiring values for certain fields to be drawn from ontologies, and creating a structured eligibility criteria element would improve the reusability of data from ClinicalTrials.gov in systematic reviews, metanalyses, and matching of eligible patients to trials.

Pilot test of an accrual Common Metric for the NIH Clinical and Translational Science Awards (CTSA) Consortium: Metric feasibility and data quality

Failure to accrue participants into clinical trials incurs economic costs, wastes resources, jeopardizes answering research questions meaningfully, and delays translating research discoveries into improved health. This paper reports the results of a pilot test of the Median Accrual Ratio (MAR) metric developed as a part of the Common Metrics Initiative of the NIH's National Center for Advancing Translational Science (NCATS) Clinical and Translational Science Award (CTSA) Consortium. Using the metric is intended to enhance the ability of the CTSA Consortium and its "hubs" to increase subject accrual into trials within expected timeframes. The pilot test was undertaken at Tufts Clinical and Translational Science Institute (CTSI) with eight CTSA Consortium hubs. We describe the pilot test methods, and results regarding feasibility of collecting metric data and the quality of data that was collected. Participating hubs welcomed the opportunity to assess accrual efforts, but experienced challenges in collecting accrual metric data due to insufficient infrastructure and inconsistent implementation of electronic data systems and lack of uniform data definitions. Also, the metric could not be constructed for all trial designs, particularly those using competitive enrollment strategies. We offer recommendations to address the identified challenges to facilitate progress to broad accrual metric data collection and use.

"I Want to Do It, But I Want to Make Sure That I Do It Right." Views of Patients with Parkinson's Disease Regarding Early Stem Cell Clinical Trial Participation

Background: First-in-human clinical trials with stem cells for Parkinson's disease (PD) are on the horizon. Their epistemic success depends on ensuring the participation of a sufficient number and appropriately diverse group of patients with PD. Their ethical soundness requires that the research community ensures that subjects' decisions about whether to participate or not are consistent with participants' values, motivations, and goals. We sought to identify PD patients' knowledge, concerns, and expectations regarding early-phase stem cell research in PD. Methods: We conducted five semi-structured focus groups with patients with PD. Group discussions were recorded, transcribed, and coded to identify participants' knowledge, concerns, and expectations regarding participation in early stem cell clinical research in PD. Results: Four themes were generated from our data analysis: (1) participants' skepticism about the potential benefits of these trials; (2) their desire to obtain information about various aspects related to this research; (3) a recognition that accessing available knowledge was often difficult; and (4) the relevance of trusting relationships with various stakeholders. Conclusions: Participants expressed skepticism about the immediate impact of stem cell research. Nonetheless, such skepticism often reflected an appropriate consideration of the risks and potential benefits of participating in high-risk clinical trials. Despite their skepticism, participants were eager to learn more about stem cell research and clinical trials processes. They identified consistently trusted avenues of knowledge on these topics, but they often found it difficult to access relevant information or to determine its value.

A multi-state model analysis of the time from ethical approval to publication of clinical research studies

Background

Results of medical research should be made publicly available in a timely manner to enable patients and health professionals to make informed decisions about health issues. We aimed to apply a multi-state model to analyze the overall time needed to publish study results, and to examine predictors of the timing of transitions within the research process from study initiation through completion/discontinuation to eventual publication.

Methods

Using a newly developed multi-state model approach, we analysed the effect of different study-related factors on each of the transitions from study approval to eventual publication, using a data set of clinical studies approved by a German research ethics committee between 2000 and 2002.

Results

Of 917 approved studies, 806 were included in our analyses. About half of the clinical studies which began were subsequently published as full articles, and the median time from study approval to publication was 10 years. Differences across model states were apparent; several factors were predictive of the transition from study approval to completion, while funding source and collaboration were predictive of the transition from completion to publication.

Conclusions

The proposed multi-state model approach permits a more comprehensive analysis of time to publication than a simple examination of the transition from approval to publication, and thus the findings represent an advance on previous studies of this aspect of the research process.

A pilot randomized trial of five financial incentive strategies to increase study enrollment and retention rates

Background

Enrollment and retention difficulties remain major barriers to conducting clinical trials. Financial incentives may promote clinical trial enrollment, however delivery methods to maximize enrollment, maximize retention, and minimize cost remains uncertain.

Methods

We conducted a single-blind, web-based randomized controlled trial of five financial incentive strategies on enrollment and retention rates in a longitudinal study of advance directives among community-dwelling older adults. Participants were eligible to receive a fixed total financial incentive, but the disbursement amounts at each study timepoint (baseline, 2-weeks, 4-weeks, and 6-weeks) differed between study arms. At each timepoint, participants completed a different advance directive. We conducted an intention-to-treat analysis for the primary and secondary outcomes of enrollment and retention.

Results

1803 adults were randomized to one of five incentive strategies: constant n = 361; increasing n = 357; U-shaped n = 361; surprise n = 360; self-select n = 364. Overall, 989 (54.9%) participants elected to enroll in the advance directive study. There were no differences in enrollment rates between the control (constant 53.5%) and any of the four intervention study arms (increasing 54.3%, p = 0.81; U-shaped 57.3%, p = 0.30; surprise 56.9%, p = 0.35; and self-select 52.2%, p = 0.73). There were no differences in retention rates between the control (constant 2.1%) and any of the four intervention study arms (increasing 5.2%, p = 0.09; U-shaped 3.9%, p = 0.23; surprise 2.4%, p = 0.54; self-select 2.1%, p = 0.63).

Conclusions

Financial incentive programs for trial enrollment informed by behavioral economic insights were no more effective than a constant-payment approach in this web-based pilot study.

Who says "no" to participating in stroke clinical trials and why: an observational study from the Vancouver Stroke Program

BACKGROUND

Successful stroke trials require adequate recruitment. In this observational study, we assessed reasons for refusal to provide informed consent in eligible patients approached for clinical trial participation at the Vancouver Stroke Program.

METHODS

We assessed screening logs from four trials that were actively recruiting at our center: three randomized trials, two of which investigated different antithrombotic strategies for secondary prevention (NAVIGATE-ESUS, NCT02313909 12/2014; DATAS-II, NCT02295826 11/2014) and one that investigated surgery plus medical management versus medical management alone for primary prevention (CREST-2, NCT02089217 03/2014). The fourth study was observational and non-randomized; all participants received an external monitoring device (PROPHECY, NCT03712865 10/2018). Screening logs from June 2015 to April 2017 were reviewed retrospectively. Subsequently, we used a prospective structured case report form for screening (May 2017-March 2018). We assessed and compared refusal rates between trials, demographics of those refusing consent, and their reasons for doing so. We used descriptive statistics, chi-square and Fisher's exact tests as appropriate for non-parametric data, and t-tests for parametric data. We examined likelihood of refusal by sex using multivariable logistic regression models including age and trial intervention as co-variables.

RESULTS

A total of 235 patients (43% women) were approached for consent. More patients refused the surgical (59%) and antithrombotic trials (53%) compared with the non-randomized external monitoring device study (13%) (p < 0.001). Surgical trial refusals were primarily due to a desire for certainty in receiving a particular intervention (39%), with the majority of those patients wanting surgery. Refusals for the antithrombotic trials were mainly due to concerns with the potential side effects of the study drug (41%); refusals in the device trial were mainly due to disinterest (46%). Women refused participation more often than men (48% vs 33%). Women remained less likely to consent than men, even after adjustment for age and trial intervention (OR 0.46, 95% CI 0.26-0.82, p = 0.009).

CONCLUSIONS

Concern surrounding drug safety, randomization, and disinterest were the chief deterrents to enrolment; there were also differences in rates of consent by gender. A better understanding of why patients refuse participation in stroke trials may help to develop future patient-directed communication strategies to improve enrolment. Further research is required to better understand the reasons underlying gender disparities in consent rates.

Evolving Landscape of Clinical Trials in Heart Failure: Patient Populations, Endpoint Selection, and Regions of Enrollment

PURPOSE OF REVIEW

Clinical trial design and execution are evolving as increasingly important considerations with respect to the success of heart failure trials. The current review highlights temporal trends in characteristics of heart failure clinical trials.

RECENT FINDINGS

Recent trials in heart failure have required longer recruitment phases, displayed inefficient enrollment rates, increased use of composite and nonfatal endpoints, undergone rapid globalization, and gradually increased focus on heart failure with preserved ejection fraction. Understanding patterns and trends in clinical trial design and execution may inform future planning and conduct of trials of heart failure therapeutics.

Randomized evaluation of trial acceptability by INcentive (RETAIN): Study protocol for two embedded randomized controlled trials

INTRODUCTION

The most common and conceptually sound ethical concerns with financial incentives for research participation are that they may (1) represent undue inducements by blunting peoples' perceptions of research risks, thereby preventing fully informed consent; or (2) represent unjust inducements by encouraging enrollment preferentially among the poor. Neither of these concerns has been shown to manifest in studies testing the effects of incentives on decisions to participate in hypothetical randomized clinical trials (RCTs), but neither has been assessed in real RCTs.

METHODS AND ANALYSES

We are conducting randomized trials of real incentives embedded within two parent RCTs. In each of two trials conducted in parallel, we are randomizing 576 participants to one of three incentive groups. Following preliminary determination of patients' eligibility in the parent RCT, we assess patients' research attitudes, demographic characteristics, perceived research risks, time spent reviewing consent documents, ability to distinguish research from patient care, and comprehension of key trial features. These quantitative assessments will be supplemented by semi-structured interviews for a selected group of participants that more deeply explore patients' motivations for trial participation. The trials are each designed to have adequate power to rule out undue and unjust inducement. We are also exploring potential benefits of incentives, including possible increased attention to research risks and cost-effectiveness.

Pediatric Trials Run in India: An Analysis of Clinical Trials.gov 2006-2015

OBJECTIVE

To present a snapshot of 10 y of pediatric research, with a focus on trials with at least one enrolling site in India.

METHODS

The study included all interventional trials registered at ClinicalTrials.gov from January 2006 through December 2015, enrolling patients aged 0 to 18 y. The database for Aggregate Analysis of ClinicalTrials.gov (AACT) was the data source used.

RESULTS

Nine thousand, six hundred forty-eight pediatric clinical studies were identified. Of these, 193 had at least one enrolling site in India. The primary purpose for most of these trials was treatment (n = 92) and prevention (n = 65) coupled with an efficacy and/or safety endpoint (n = 158). Infant and toddlers were eligible for enrollment in the majority of trials (97%) while neonates only in 22% of trials. The rate of early termination or withdrawal was 5%. The most commonly studied conditions were bacterial infections, viruses, digestive and mental diseases. Overall, communicable diseases (n = 75) and major non-communicable diseases (n = 72) were equally investigated.

CONCLUSIONS

The most commonly studied therapeutic areas in trials enrolling from India and registered in ClinicalTrials.gov were appropriate for India public health needs and patients were not enrolled into studies inappropriately from this perspective.

Accrual monitoring in cardiovascular trials

Objective

To provide brief guidance on how to design accrual monitoring activities in a clinical trial protocol.

Setting

Two completed clinical trials that did not achieve the planned sample size, the Cost of Strategies After Myocardial Infarction (COSTAMI) trial and the Biventricular Pacing After Cardiac Surgery (BiPACS) trial.

Design

A Bayesian monitoring tool, the constant accrual model, is applied retrospectively to accrual data from each case study to illustrate how the tool could be used to identify problems with accrual early in the trial period and to frame the conditions in which the approach can be used in practice.

Results

After 312 days and 155 patients enrolled in the COSTAMI trial, accrual could be classified as ‘off target’ on the basis of statistical criteria outlined in the protocol. As for the BiPACS trial, after 2 years, it was already evident that the accrual was ‘considerably off target’.

Conclusions

Prompt awareness of a high risk of accrual failure could trigger different interventions to overcome protocol-related, patient-related or investigator-related barriers to recruitment or ultimately contribute to an early stopping decision due to recruitment futility.

Accrual prediction models should be included as standard tools for routine monitoring activities in cardiovascular research. Among them, methods relying on the Bayesian approach are particularly attractive, as they can naturally update past evidence when actual accrual data becomes available.