Two Decades of Cardiovascular Trials With Primary Surrogate Endpoints: 1990-2011

Regulatory Approval vs Guideline Endorsement of Novel BP-Lowering Treatments

This Viewpoint describes the benefits and barriers of conducting cardiovascular disease outcome trials to provide evidence of effectiveness of novel blood pressure (BP)–lowering therapies in reducing hypertension.

Drug Discovery and Development for Heart Failure Using Multi-Omics Approaches

Heart failure (HF) is a complex, heterogeneous syndrome with rising prevalence and high morbidity and mortality. The pathophysiology and diverse etiologies of HF present significant challenges for developing effective therapies. Omics technologies-including genomics, proteomics, transcriptomics, metabolomics, and epigenomics-have reshaped our understanding of HF at the molecular level, uncovering new biomarkers and potential therapeutic targets. Omics also enable insights into individualized treatment responses, the risks of adverse drug effects, and patient stratification for clinical trials. This review explores how multi-omics can enhance heart failure drug discovery and development across all stages of the therapeutic pipeline: (1) target selection and lead identification, (2) preclinical studies, and (3) clinical trials. By integrating omics approaches throughout the drug development process, we can accelerate the discovery of more effective and personalized therapies for heart failure.

Therapeutic value of new medicines not submitted to Health Canada 2014-2021: Cross-sectional study

OBJECTIVES

To examine whether there has been a change in the number of therapeutically important new medicines not being introduced into the Canadian market in light of the December 2017 announcement of regulatory changes to lower Canadian prices.

METHODS

A list was compiled of medicines approved by the Food and Drug Administration (FDA) between 2014-2021 but not submitted to Health Canada. The therapeutic value of these medicines was assessed based on evaluations by two independent sources. If no evaluation was available, potential therapeutic value was determined based on the presence of one or more of three medicine characteristics. Interrupted time series was used to determine if there were changes in overall new medicine introductions and therapeutically important new medicines.

RESULTS

The FDA approved 364 new medicines of which 116 (31.9%) were not submitted to Health Canada. There was a decrease in overall annual number of submissions but that was not related to the announcement at the end of 2017. There was no change in the introduction of therapeutically important new medicines as a percent of all medicines not marketed in Canada but there was a decrease in the absolute number.

CONCLUSIONS

The number of therapeutically important medicines not being introduced into Canada is increasing but that is not related to the proposed price reforms.

Prediction of therapeutic value of new drugs approved by health Canada from 2011-2020: A cross-sectional study

Objectives

To examine whether a combination of three characteristics of new drugs - review type, outcome of premarket trials (surrogate or clinical) and first-in-class is associated with significant therapeutic value.

Design

Cross-sectional analysis of new drugs approved by Health Canada from January 1, 2011 to December 31, 2020.

Setting

Canada.

Participants

New drugs approved by Health Canada for which therapeutic evaluations, trial outcomes and first-in-class status was available.

Main outcome measures

Distribution of therapeutic value (major, moderate, little to no) depending on how many of the three characteristics were present for each drug.

Results

Health Canada approved 340 drugs of which 243 had data available for analysis. If all three characteristics were present 10 out of the 20 drugs had a major therapeutic rating. Conversely if none were present only 2 drugs out of 37 had a major therapeutic rating.

Conclusion

This study introduces a new evaluation method for determining whether new drugs will have major therapeutic value that appears to be more successful than relying only on the type of review that drugs receive.

Range and Consistency of Cardiovascular Outcomes Reported by Clinical Trials in Kidney Transplant Recipients: A Systematic Review

Cardiovascular disease is a major cause of morbidity and mortality in kidney transplant recipients. Trial evidence to improve cardiovascular outcomes is limited by inconsistent reporting of outcomes, which may also lack patient-relevance. This study aimed to assess the range and consistency of cardiovascular outcomes reported by contemporary trials in kidney transplant recipients.

Methods

A systematic review of all randomized controlled trials involving adult kidney transplant recipients that reported at least 1 cardiovascular outcome from January 2012 to December 2019 was performed, including Embase, MEDLINE, Cochrane, and ClinicalTrials.gov electronic databases. Trial characteristics were extracted and all levels of specification of the cardiovascular outcome measures reported were analyzed (the measure definition, metric' and method of aggregation). Measures assessing a similar aspect of cardiovascular disease were categorized into outcomes.

Results

From 93 eligible trials involving 27 609 participants, 490 outcome measures were identified. The outcome measures were grouped into 38 outcomes. A cardiovascular composite was the most common outcome reported (40 trials, 43%) followed by cardiovascular mortality (42%) and acute coronary syndrome (31%). Cardiovascular composite was also the most heterogeneous outcome with 77 measures reported followed by cardiovascular mortality (n = 58) and inflammatory biomarkers (n = 51). The most common cardiovascular composite outcome components reported were major cardiovascular events (18 trials), stroke unspecified (11 trials), and myocardial infarction unspecified (10 trials).

Conclusions

There is substantial heterogeneity in cardiovascular outcome reporting in kidney transplant trials.

One-Year Follow-Up of Vascular Intervention Trials Disrupted by the COVID-19 Pandemic: A Use-Case landscape

INTRODUCTION

The COVID-19 pandemic had an unprecedented impact on cardiovascular clinical research. The decision-making and state of study operations in cardiovascular trials 1-year after interruption has not been previously described.

METHODS

In the spring of 2020, we created a pandemic impact task force to develop a landscape of use case scenarios from 17 device trials of peripheral artery disease (PAD) and coronary artery disease (CAD) interventions. In conjunction with publicly available (clinictrials.gov) study inclusion criteria, primary endpoints and study design, information was shared for this use-case landscape by trial leadership and data owners.

RESULTS

A total of 17 actively enrolling trials (9 CAD and 8 PAD) volunteered to populate the use case landscape. All 17 were multicenter studies (12 in North America and 5 international). Fifteen studies were industry-sponsored, of which 13 were FDA approved IDEs, one was PCORI-sponsored and two were sponsored by the NIH. Enrollment targets ranged from 150 to 9000 pts. At the time of interruption, 5 trials were <20 % enrolled, 9 trials were 50-80 % enrolled and 3 trials were >80 % enrolled. At 1 year, the majority of studies were continuing to enroll in the context of more sporadic but ongoing pandemic activity.

CONCLUSIONS

At 1 year from the first surge interruptions, most trials had resumed enrollment. Trials most heavily interrupted were trials early in enrollment and those trials not able to pivot to virtual patient and site visits. Further work is needed to determine the overall impact on vascular intervention trials disrupted during the COVID-19 pandemic.

Scoping and targeted reviews to support development of SPIRIT and CONSORT extensions for randomised controlled trials with surrogate primary endpoints: protocol

INTRODUCTION

Using a surrogate endpoint as a substitute for a primary patient-relevant outcome enables randomised controlled trials (RCTs) to be conducted more efficiently, that is, with shorter time, smaller sample size and lower cost. However, there is currently no consensus-driven guideline for the reporting of RCTs using a surrogate endpoint as a primary outcome; therefore, we seek to develop SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) and CONSORT (Consolidated Standards of Reporting Trials) extensions to improve the design and reporting of these trials. As an initial step, scoping and targeted reviews will identify potential items for inclusion in the extensions and participants to contribute to a Delphi consensus process.

METHODS AND ANALYSIS

The scoping review will search and include literature reporting on the current understanding, limitations and guidance on using surrogate endpoints in trials. Relevant literature will be identified through: (1) bibliographic databases; (2) grey literature; (3) handsearching of reference lists and (4) solicitation from experts. Data from eligible records will be thematically analysed into potential items for inclusion in extensions. The targeted review will search for RCT reports and protocols published from 2017 to 2021 in six high impact general medical journals. Trial corresponding author contacts will be listed as potential participants for the Delphi exercise.

ETHICS AND DISSEMINATION

Ethical approval is not required. The reviews will support the development of SPIRIT and CONSORT extensions for reporting surrogate primary endpoints (surrogate endpoint as the primary outcome). The findings will be published in open-access publications.This review has been prospectively registered in the OSF Registration DOI: 10.17605/OSF.IO/WP3QH.

Protocol for the development of SPIRIT and CONSORT extensions for randomised controlled trials with surrogate primary endpoints: SPIRIT-SURROGATE and CONSORT-SURROGATE

INTRODUCTION

Randomised controlled trials (RCTs) may use surrogate endpoints as substitutes and predictors of patient-relevant/participant-relevant final outcomes (eg, survival, health-related quality of life). Translation of effects measured on a surrogate endpoint into health benefits for patients/participants is dependent on the validity of the surrogate; hence, more accurate and transparent reporting on surrogate endpoints is needed to limit misleading interpretation of trial findings. However, there is currently no explicit guidance for the reporting of such trials. Therefore, we aim to develop extensions to the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) and CONSORT (Consolidated Standards of Reporting Trials) reporting guidelines to improve the design and completeness of reporting of RCTs and their protocols using a surrogate endpoint as a primary outcome.

METHODS AND ANALYSIS

The project will have four phases: phase 1 (literature reviews) to identify candidate reporting items to be rated in a Delphi study; phase 2 (Delphi study) to rate the importance of items identified in phase 1 and receive suggestions for additional items; phase 3 (consensus meeting) to agree on final set of items for inclusion in the extensions and phase 4 (knowledge translation) to engage stakeholders and disseminate the project outputs through various strategies including peer-reviewed publications. Patient and public involvement will be embedded into all project phases.

ETHICS AND DISSEMINATION

The study has received ethical approval from the University of Glasgow College of Medical, Veterinary and Life Sciences Ethics Committee (project no: 200210051). The findings will be published in open-access peer-reviewed publications and presented in conferences, meetings and relevant forums.

The need for increased pragmatism in cardiovascular clinical trials

The majority of cardiovascular randomized controlled trials (RCTs) test interventions in selected patient populations under explicitly protocol-defined settings. Although these ‘explanatory’ trial designs optimize conditions to test the efficacy and safety of an intervention, they limit the generalizability of trial findings in broader clinical settings. The concept of ‘pragmatism’ in RCTs addresses this concern by providing counterbalance to the more idealized situation underpinning explanatory RCTs and optimizing effectiveness over efficacy. The central tenets of pragmatism in RCTs are to test interventions in routine clinical settings, with patients who are representative of broad clinical practice, and to reduce the burden on investigators and participants by minimizing the number of trial visits and the intensity of trial-based testing. Pragmatic evaluation of interventions is particularly important in cardiovascular diseases, where the risk of death among patients has remained fairly stable over the past few decades despite the development of new therapeutic interventions. Pragmatic RCTs can help to reveal the ‘real-world’ effectiveness of therapeutic interventions and elucidate barriers to their implementation. In this Review, we discuss the attributes of pragmatism in RCT design, conduct and interpretation as well as the general need for increased pragmatism in cardiovascular RCTs. We also summarize current challenges and potential solutions to the implementation of pragmatism in RCTs and highlight selected ongoing and completed cardiovascular RCTs with pragmatic trial designs.

In this Review, Khan and colleagues discuss the benefits and challenges of including pragmatism in the design, conduct and interpretation of randomized controlled trials (RCTs) for cardiovascular disease and highlight selected ongoing and completed cardiovascular RCTs that incorporate a pragmatic design.

Most cardiovascular randomized controlled trials (RCTs) conducted to date have been ‘explanatory’, that is, designed to study the intervention in optimized conditions with selected patient populations and frequent protocolized assessments.

Although explanatory RCT designs increase validity, they limit the generalizability of trial findings, whereas a ‘pragmatic’ approach to RCTs yields findings more relevant to real-world practice.

In pragmatic RCTs, interventions are tested in patients who are broadly representative of the condition being studied, and the study is aligned with routine clinical care to reduce costs and organizational burden.

Although pragmatic RCTs tend to attenuate estimates of treatment effects, they do provide a more realistic understanding of population-level effectiveness and costs than explanatory trials.

Pragmatic trials can highlight barriers to the implementation of therapies and are better suited than explanatory RCTs to assessing the effects of implementation strategies and health-care policies at the population level.

Widespread implementation of pragmatic trials would require the development of technological infrastructure to collect and share data as well as regulatory guidelines amenable to findings derived from routinely collected data.

Biomarker changes as surrogate endpoints in early-phase trials in heart failure with reduced ejection fraction

AIMS

No biomarker has achieved widespread acceptance as a surrogate endpoint for early-phase heart failure (HF) trials. We assessed whether changes over time in a panel of plasma biomarkers were associated with subsequent morbidity/mortality in HF with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

In 1040 patients with HFrEF from the BIOSTAT-CHF cohort, we investigated the associations between changes in the plasma concentrations of 30 biomarkers, before (baseline) and after (9 months) attempted optimization of guideline-recommended therapy, on top of the BIOSTAT risk score and the subsequent risk of HF hospitalization/all-cause mortality using Cox regression models. C-statistics were calculated to assess discriminatory power of biomarker changes/month-nine assessment. Changes in N-terminal pro-B-type natriuretic peptide (NT-proBNP) and WAP four-disulphide core domain protein HE4 (WAP-4C) were the only independent predictors of the outcome after adjusting for their baseline plasma concentration, 28 other biomarkers (both baseline and changes), and BIOSTAT risk score at baseline. When adjusting for month-nine rather than baseline biomarkers concentrations, only changes in NT-proBNP were independently associated with the outcome. The C-statistic of the model including the BIOSTAT risk score and NT-proBNP increased by 4% when changes were considered on top of baseline concentrations and by 1% when changes in NT-proBNP were considered on top of its month-nine concentrations and the BIOSTAT risk score.

CONCLUSIONS

Among 30 relevant biomarkers, a change over time was significantly and independently associated with HF hospitalization/all-cause death only for NT-proBNP. Changes over time were modestly more prognostic than baseline or end-values alone. Changes in biomarkers should be further explored as potential surrogate endpoints in early phase HF trials.

Is There a Causal Link Between Periodontitis and Cardiovascular Disease? A Concise Review of Recent Findings

There is substantial evidence in support of an association between periodontitis and cardiovascular disease. The most important open question related to this association is causality. This article revisits the question of causality by reviewing intervention studies and systematic reviews and meta analyses published in the last 3 years. Where are we now in answering this question? Whilst systematic reviews and epidemiological studies continue to support an association between the diseases, intervention studies fall short in determining causality. There is a dearth of good-quality, blinded randomised control trials with cardiovascular disease outcomes. Most studies use surrogate markers/biomarkers for endpoints, and this is problematic as they may not be reflective of cardiovascular disease status. This review further highlights another issue with surrogate markers/biomarkers: the potential for collider bias. Ethical considerations surrounding nontreatment have led to calls for a well-annotated database containing in-depth dental health data. Finally, a relatively new and important risk factor for cardiovascular disease, clonal haematopoiesis of indeterminate potential, is discussed. Clonal haematopoiesis of indeterminate potential increases cardiovascular risk by more than 40%, and inflammation is a contributing factor. The impact of periodontal disease on this emerging risk factor has yet to be explored. Although the question of causality in the association between periodontal disease and cardiovascular disease remains unanswered, the importance of good oral health in maintaining good heart health is reiterated.

Surrogate endpoint evaluation using data from one large global randomized controlled trial

BACKGROUND

Robust identification of surrogate endpoints can help accelerate the development of pharmacotherapies for diseases traditionally evaluated using true endpoints associated with prolonged follow-up. The meta-analysis-based surrogate endpoint evaluation (SEE) integrates data from multiple, usually smaller, trials to statistically confirm a surrogate endpoint as a robust proxy for the true endpoint. To test the applicability of SEE when only a single, larger trial is available, we analysed the cardiovascular (CV) survival endpoint from the large multinational trial LEADER (9340 subjects) that confirmed the CV safety of a diabetes drug (liraglutide). We evaluated if using country as a trial unit adequately facilitated the meta-analysis and calculation of R² by country group.

METHODS

Data were grouped by country, ensuring at least 30 CV deaths (497 in total) in each of the nine resulting by-country groups. In a two-step SEE on the grouped dataset, we first fitted the group-specific Cox proportional hazard models; next, on the trial-level, we regressed the estimated hazard ratio (HR; liraglutide vs placebo) of the true endpoints (CV death: 497 events, or all-cause death: 828 events) on the HR of the surrogate endpoint (major CV adverse event [MACE]: 1302 events) and derived the group-specific R² and its 95% confidence interval (CI).

RESULTS

Group-level surrogacy of MACE was supported for CV death but not for all-cause death, with [Formula: see text] values of 0.85 [0.63;1.00]_{95% CI} and 0.23 [0.00;0.67]_{95% CI}, respectively. Sensitivity analyses using different grouping approaches (e.g. grouping by region) corroborated the robustness of the conclusions as well as the appropriateness of the data-grouping approaches.

CONCLUSIONS

We derived a specific grouping approach to successfully apply SEE on data from a single trial. This may allow for the statistically robust identification and validation of surrogate endpoints based on the abundance of large monolithic outcome trials conducted as part of drug development programmes in, for example, diabetes.

Efficacy and safety outcomes of proposed randomized controlled trials investigating hydroxychloroquine and chloroquine during the early stages of the COVID-19 pandemic

Aims

To assess whether randomized clinical trials (RCTs) proposed to evaluate the treatment of patients with COVID‐19 with hydroxychloroquine (HQ) or chloroquine early in the pandemic included plans to measure outcomes that would translate into meaningful efficacy/effectiveness and safety outcomes.

Methods

The World Health Organization International Clinical Trials Registry Platform database was searched for registers of RCTs evaluating HQ or chloroquine, alone or in combination, compared with other treatments for patients diagnosed with COVID‐19. The final search was performed on 8 April 2020.

Results

Among 51 registered RCTs (median sample size 262; interquartile range: 100, 520), 34 (67%) reported a clinical outcome, 12 (24%) a surrogate outcome, and 5 (10%) a combination of clinical and surrogate outcomes as primary endpoints. Six (15%) trials included the World Health Organization scale for clinical improvement as a primary clinical outcome. Clinical improvement and mortality accounted for 45% of the unique domains among 18 clinical outcome domains of efficacy. Twenty‐four (47%) RCTs did not describe plans to assess safety outcomes; when assessed, safety outcomes were determined in generic terms of total, severe or serious adverse events.

Conclusion

The RCTs investigating HQ or chloroquine during the early stages of the COVID‐19 pandemic included heterogeneous and insufficient approaches to measure efficacy/effectiveness and safety relevant to patients and clinical practice. These findings provide insights to inform clinical and regulatory decisions that can be drawn about the efficacy/effectiveness and safety of these agents in patients with COVID‐19. Trialists need to adapt quickly to the research progress on COVID‐19, ensuring that core outcome measures are assessed in ongoing RCTs.

Non-inferiority trials using a surrogate marker as the primary endpoint: An increasing phenotype in cardiovascular trials

BACKGROUND/AIMS

Non-inferiority trials are increasing in cardiovascular medicine, with approval of many drugs and devices on the basis of such studies. Surrogate markers as primary endpoints have been also more frequently used for efficient assessment of cardiovascular interventions. However, there is uncertainty about their concordance with clinical outcomes. Non-inferiority design using a surrogate marker as a primary endpoint may pose particular challenges in clinical interpretation. We sought to explore the publication trends, methodology, and reporting features of non-inferiority cardiovascular trials that used a primary surrogate marker as the primary endpoint.

METHODS

We searched six high-impact journals (The New England Journal of Medicine, The Journal of the American Medical Association, The Lancet, The Journal of the American College of Cardiology, Circulation, and European Heart Journal) from 1 January 1990 to 31 December 2018 and identified non-inferiority cardiovascular trials that used a surrogate marker as the primary endpoint. We assessed the non-inferiority margin reported in the manuscript and other publicly available platforms (e.g. protocol, clinicaltrials.gov). We also determined whether the included non-inferiority trials with surrogate markers as primary endpoints were followed by clinical outcome trials.

RESULTS

We screened 15,553 publications and identified 247 cardiovascular trials that used a non-inferiority design. Of these, 37 had a surrogate marker as a primary endpoint (18 drug trials, 13 device trials, 6 others). All of these non-inferiority trials with surrogate outcomes were published after 2000, mostly in cardiology journals (13 in The Journal of the American College of Cardiology, 9 in European Heart Journal, 8 in Circulation, 6 in The Lancet, 1 in The New England Journal of Medicine), and their publication rate increased over time (p < 0.001 for linear trend). The median number of patients in the primary analysis was 300 (interquartile range: 202-465). The study protocol or a methods paper was publicly available for only 13 (35.1%) trials, of which the non-inferiority margin was not reported in 4 trials. In 16 studies (43.2%), the manuscript did not acknowledge the limitations of using a surrogate endpoint or the need for a definitive clinical outcome trial. Thirty-four trials (91.9%) concluded that the tested intervention met non-inferiority criteria. However, only five (13.5%) were followed by clinical outcomes trials the results of which did not always confirm non-inferiority.

CONCLUSION

Non-inferiority trials that use a surrogate marker as the primary endpoint are being increasingly performed. However, these trials pose particular challenges with design, reporting, and interpretation, which are not systematically and consistently addressed or reported.

Quality of advertisements for prescription drugs in family practice medical journals published in Australia, Canada and the USA with different regulatory controls: a cross-sectional study

OBJECTIVE

To assess if different forms of regulation lead to differences in the quality of journal advertisements.

DESIGN

Cross-sectional study.

PARTICIPANTS

Thirty advertisements from family practice journals published from 2013 to 2015 were extracted for three countries with distinct regulatory pharmaceutical promotion systems: Australia, Canada and the USA.

PRIMARY AND SECONDARY OUTCOME MEASURES

Advertisements under each regulatory system were compared concerning three domains: information included in the advertisement, references to scientific evidence and pictorial appeals and portrayals. An overall ranking for advertisement quality among countries was determined using the first two domains as the information assessed has been associated with more appropriate prescribing.

RESULTS

Advertisements varied significantly for number of claims with quantitative benefit (Australia: 0.0 (0.0-3.0); Canada: 0.0 (0.0-5.0); USA: 1.0 (0.0-6.0); p=0.01); statistical method used in reporting benefit (relative risk reduction, absolute risk reduction and number needed to treat; Australia: 6.7%, n=2; Canada: 10.0%, n=3; USA: 36.6%, n=11; p=0.02); mention of adverse effects, warnings or contraindications (Australia: 13.3%, n=4; Canada: 23.3%, n=7; USA: 53.3%, n=16; p=0.002); equal prominence between safety and benefit information (Australia: 25.0%, n=1; Canada: 28.6%, n=2; USA: 75.0%, n=12; p=0.04); and methodological quality of references score (Australia: 0.4150 (0.25-0.70); Canada: 0.25 (0.00-0.63); USA: 0.25 (0.00-0.75); p<0.001). The USA ranked first, Canada second and Australia third for overall quality of journal advertisements. Significant differences for humour appeals (Australia: 3.3%, n=1; Canada: 13.3%, n=4; USA: 26.7%, n=8; p=0.04), positive emotional appeals (Australia: 26.7%, n=8; Canada: 60.0%, n=18; USA: 50.0%, n=15; p=0.03), social approval portrayals (Australia: 0.0%, n=0; Canada: 0.0%, n=0; USA: 10.0%, n=3; p=0.04) and lifestyle or work portrayals (Australia: 43.3%, n=13; Canada: 50.0%, n=15; USA: 76.7%, n=23; p=0.02) were found among countries.

CONCLUSIONS

Different regulatory systems influence journal advertisement quality concerning all measured domains. However, differences may also be attributed to other regulatory, legal, cultural or health system factors unique to each country.

The impact of non-medical switching among ambulatory patients: an updated systematic literature review

Background: Non-medical switching (NMS) is defined as switching to a clinically similar but chemically distinct medication for reasons apart from lack of effectiveness, tolerability or adherence. Objective: To update a prior systematic review evaluating the impact of NMS on outcomes. Data sources: An updated search through 10/1/2018 in Medline and Web of Science was performed. Study selection: We included studies evaluating ≥25 patients and measuring the impact of NMS of drugs on ≥1 endpoint. Data extraction: The direction of association between NMS and endpoints was classified as negative, positive or neutral. Data synthesis: Thirty-eight studies contributed 154 endpoints. The direction of association was negative (n = 48; 31.2%) or neutral (n = 91; 59.1%) more often than it was positive (n = 15; 9.7%). Stratified by endpoint type, NMS was associated with a negative impact on clinical, economic, health-care utilization and medication-taking behavior in 26.9%,41.7%,30.3% and 75.0% of cases; with a positive effect seen in 3.0% (resource utilization) to 14.0% (clinical) of endpoints. Of the 92 endpoints from studies performed by the entity dictating the NMS, 88.0%were neutral or positive; whereas, only 40.3%of endpoints from studies conducted separately from the interested entity were neutral or positive. Conclusions: NMS was commonly associated with negative or neutral endpoints and was seldom associated with positive ones.

Pharmaceutical Drugs of Uncertain Value, Lifecycle Regulation at the US Food and Drug Administration, and Institutional Incumbency

Policy Points The US Food and Drug Administration (FDA) has in recent years allowed onto the market several drugs with limited evidence of safety and effectiveness, provided that manufacturers agree to carry out additional studies while the drugs are in clinical use. Studies suggest that these postmarketing requirements (PMRs) frequently lack transparency, are subject to delays, and fail to answer the questions of greatest clinical importance. Yet, none of the literature speaks directly to the challenges that the FDA-as a regulatory institution-encounters in enforcing PMRs. Through a series of interviews with FDA leadership, this article analyzes and situates those challenges in the midst of political threats to the FDA's public health mandate.

CONTEXT

Modern pharmaceutical regulation is premised on a rigorous examination of a drug's safety and effectiveness prior to its lawful sale. However, since the 1990s, the US Food and Drug Administration (FDA) has gradually shifted to a model of "lifecycle" regulation that increasingly relies on postmarketing requirements (PMRs) to encourage studies of drug safety and effectiveness following regulatory approval. This article examines the range of legal, institutional, and political challenges that FDA faces in the context of lifecycle regulation.

METHODS

Document-based legal and policy analysis was combined with a set of semistructured interviews of current and former FDA officials (n = 23) in order to explore the implications of the FDA's use of PMRs. The median interview time per official was 61 minutes, with a range of 24 to 227 minutes. All of the officials interviewed occupied positions of leadership and influence within the FDA, such as directors of an FDA center or office, key legal counsel on agency-wide policy initiatives, and the commissioner of the FDA.

FINDINGS

Insufficient resources and coordination within the FDA, inadequate legal authorities, and the political economy of withdrawing an approved indication in the face of opposition from companies and patients all contribute to the observed shortcomings in the FDA's use and enforcement of PMRs. Further, the FDA is fully aware of these challenges, yet is seemingly resigned to and resistant to criticism of its use of PMRs.

CONCLUSIONS

This study of the FDA's shift toward lifecycle regulation reveals not simply an agency in transition, but rather an agency on guard against a set of larger political threats to its mandate. This can be characterized as a state of institutional incumbency in which the agency is engaged in an effort to reproduce key features of the regulatory system-in concert with regulated industries and others-while simultaneously sanctioning significant changes to the regulatory standards the FDA has long applied, to the detriment of public health.

Noninferiority Designed Cardiovascular Trials in Highest-Impact Journals

BACKGROUND

Noninferiority trials are increasingly being performed. However, little is known about their methodological quality. We sought to characterize noninferiority cardiovascular trials published in the highest-impact journals, features that may bias results toward noninferiority, features related to reporting of noninferiority trials, and the time trends.

METHODS

We identified cardiovascular noninferiority trials published in JAMA, Lancet, or New England Journal of Medicine from 1990 to 2016. Two independent reviewers extracted the data. Data elements included the noninferiority margin and the success of studies in achieving noninferiority. The proportion of trials showing major or minor features that may have affected the noninferiority inference was determined. Major factors included the lack of presenting the results in both intention-to-treat and per-protocol/as-treated cohorts, α>0.05, the new intervention not being compared with the best alternative, not justifying the noninferiority margin, and exclusion or loss of ≥10% of the cohort. Minor factors included suboptimal blinding, allocation concealment, and others.

RESULTS

From 2544 screened studies, we identified 111 noninferiority cardiovascular trials. Noninferiority margins varied widely: risk differences of 0.4% to 25%, hazard ratios of 1.05 to 2.85, odds ratios of 1.1 to 2.0, and relative risks of 1.1 to 1.8. Eighty-six trials claimed noninferiority, of which 20 showed superiority, whereas 23 (21.1%) did not show noninferiority, of which 8 also demonstrated inferiority. Only 7 (6.3%) trials were considered low risk for all the major and minor biasing factors. Among common major factors for bias, 41 (37%) did not confirm the findings in both intention-to-treat and per-protocol/as-treated cohorts and 4 (3.6%) reported discrepant results between intention-to-treat and per-protocol analyses. Forty-three (38.7%) did not justify the noninferiority margin. Overall, 27 (24.3%) underenrolled or had >10% exclusions. Sixty trials (54.0%) were open label. Allocation concealment was not maintained or unclear in 11 (9.9%). Publication of noninferiority trials increased over time (P<0.001). Fifty-two (46.8%) were published after 2010 and had a lower risk of methodological or reporting limitations for major (P=0.03) and minor factors (P=0.002).

CONCLUSIONS

Noninferiority trials in highest-impact journals commonly conclude noninferiority of the tested intervention, but vary markedly in the selected noninferiority margin, and frequently have limitations that may impact the inference related to noninferiority.

Comparison of Clopidogrel and Ticlopidine/Ginkgo Biloba in Patients With Clopidogrel Resistance and Carotid Stenting

Background and Purpose: Patients undergoing carotid artery stenting (CAS) who show low responsiveness to clopidogrel may have a higher risk of peri-procedural embolic events. This study aimed to compare the effectiveness and safety of clopidogrel and ticlopidine plus Ginkgo biloba in clopidogrel-resistant patients undergoing CAS.

Methods: In this multi-center, randomized, controlled trial, we used platelet reactivity test to select patients undergoing CAS who showed clopidogrel resistance, and compared treatments using clopidogrel and ticlopidine plus ginkgo. The primary outcome was the incidence of new ischemic lesion in the ipsilateral hemisphere of CAS. Detection of microembolic signal on transcranial Doppler was the secondary outcome. The clinical outcomes were also monitored.

Results: This trial was discontinued after 42 patients were randomized after preplanned interim sample size re-estimation indicated an impractical sample size. The primary endpoint occurred in 12/22 patients (54.5%) in the clopidogrel group and 13/20 patients (65.0%) in the ticlopidine–ginkgo group (P = 0.610). No significant differences in the presence of microembolic signal (15.0 vs. 11.8%, P = 0.580), clinical outcomes (ischemic stroke or transient ischemic attack, 0.0 vs. 5.5%; acute myocardial infarction 0.0 vs. 0.0%; all-cause death, 4.5 vs. 0.0%), or incidence of adverse events were found in the two groups. In terms of resistance to clopidogrel, treatment with ticlopidine–ginkgo significantly increased the P2Y12 Reaction Units (difference, 0.0 [−0.3–3.0] vs. 21.0 [6.0–35.0], P < 0.001).

Conclusions: In patients who showed clopidogrel resistance, ticlopidine–ginkgo treatment was safe and increased P2Y12 Reaction Units; however, compared to clopidogrel, it failed to improve surrogate and clinical endpoints in patients undergoing CAS. This multimodal biomarker-based clinical trial is feasible in neurointerventional research.

Clinical Trial Registration:http://www.clinicaltrials.gov. Unique identifier: NCT02133989.

Evaluation at scale of microbiome-derived metabolites as biomarker of flavan-3-ol intake in epidemiological studies

The accurate assessment of dietary intake is crucial to investigate the effect of diet on health. Currently used methods, relying on self-reporting and food composition data, are known to have limitations and might not be suitable to estimate the intake of many bioactive food components. An alternative are nutritional biomarkers, which can allow an unbiased assessment of intake. They require a careful evaluation of their suitability, including: (a) the availability of a precise, accurate and robust analytical method, (b) their specificity (c) a consistent relationship with actual intake. We have evaluated human metabolites of a microbiome-derived flavan-3-ol catabolite, 5-(3',4'-dihydroxyphenyl)-[gamma]-valerolactone (gVL), as biomarker of flavan-3-ol intake in large epidemiological studies. Flavan-3-ols are widely consumed plant bioactives, which have received considerable interest due to their potential ability to reduce CVD risk. The availability of authentic standards allowed the development of a validated high-throughput method suitable for large-scale studies. In dietary intervention studies, we could show that gVL metabolites are specific for flavan-3-ols present in tea, fruits, wine and cocoa-derived products, with a strong correlation between intake and biomarker (Spearman's r = 0.90). This biomarker will allow for the first time to estimate flavan-3-ol intake and further investigation of associations between intake and disease risk.

Validity of inducible ischaemia as a surrogate for adverse outcomes in stable coronary artery disease

Regional myocardial ischaemia is commonly expressed as exertional angina in patients with stable coronary artery disease (CAD). It also associates with prognosis, risk tending to increase with the severity of ischaemia. The validity of myocardial ischaemia as a surrogate for adverse clinical outcomes, however, has not been well established. Thus, in cohort studies, ischaemia testing has failed to influence rates of myocardial infarction and coronary death. Moreover, in clinical studies, pharmacological and interventional treatments that are effective in correcting ischaemia have rarely been shown to reduce cardiovascular (CV) risk. This contrasts with statins and other anti-inflammatory drugs that have no direct effect on ischaemia but improve CV outcomes by modifying the atherothrombotic disease process. Despite this, and with little evidence of patient benefit, stress testing is commonly used during the follow-up of patients with stable CAD when the demonstration of ischaemic change may be seen as a target for treatment, independently of symptomatic status. Substitution of a symptom-driven management strategy has the potential to reduce rates of non-invasive stress testing, unnecessary downstream revascularisation procedures and use of valuable resources in patients with stable CAD without adverse consequences for CV risk.

Nutrition epidemiology of flavan-3-ols: The known unknowns

Nutritional epidemiology has an important role, as it can provide long-term data from large populations and does not rely on surrogate markers for morbidity/mortality. Meaningful interpretation and applications of outcomes from epidemiological studies depend on the accurate assessment of dietary intake, which is currently mainly based on a combination of self-reporting and food composition data. Flavan-3-ols are a group of bioactives (non-essential dietary components with significant impact on health) that is a possible candidate for the development of dietary recommendations. The breadth of data available on their effect on health also provides the basis for investigating the suitability of the methods currently used in nutritional epidemiology to assess the health effects of bioactives. The outcomes of this assessment demonstrate that the limitations of currently used methods make it virtually impossible to estimate intake accurately from self-reported dietary data. This is due to the limitations of self-reporting, especially from food-frequency questionnaires, and the inability of currently used methods to deal with the high variability of food composition. Indeed, the estimated intake of flavan-3-ols, can only be interpreted as a marker of specific dietary patterns, but not as the actual intake amount. The interpretation of results from such studies are fraught with serious limitations, especially for establishing associations between intake and health and the development of dietary recommendations. Alternative assessment not affected by these limitations, such as biomarkers, are required to overcome these limitations. The development of nutritional biomarkers is therefore crucial to investigate the health effect of bioactives.

Surrogate disease markers as substitutes for chronic disease outcomes in studies of diet and chronic disease relations

Surrogate biomarkers for clinical outcomes afford scientific and economic efficiencies when investigating nutritional interventions in chronic diseases. However, valid scientific results are dependent on the qualification of these disease markers that are intended to be substitutes for a clinical outcome and to accurately predict benefit or harm. In this article, we examine the challenges of evaluating surrogate markers and describe the framework proposed in a 2010 Institute of Medicine report. The components of this framework are presented in the context of nutritional interventions for chronic diseases. We present case studies of 2 well-accepted surrogate markers [blood pressure within sodium intake and cardiovascular disease (CVD) context and low density lipoprotein-cholesterol concentrations within a saturated fat and CVD context]. We also describe additional cases in which the evidence is insufficient to validate their surrogate status. Guidance is offered for future research that evaluates or uses surrogate markers.