Lessons From COVID-19 for Pandemic Preparedness: Proceedings From a Multistakeholder Think Tank

While the coronavirus disease 2019 (COVID-19) pandemic continues to present global challenges, sufficient time has passed to reflect on lessons learned and use those insights to inform policy and approaches to prepare for the next pandemic. In May 2022, the Duke Clinical Research Institute convened a think tank with thought leaders from academia, clinical practice, the pharmaceutical industry, patient advocacy, the National Institutes of Health, the US Food and Drug Administration, and the Centers for Disease Control and Prevention to share, firsthand, expert knowledge of the insights gained from the COVID-19 pandemic and how this acquired knowledge can help inform the next pandemic response. The think tank focused on pandemic preparedness, therapeutics, vaccines, and challenges related to clinical trial design and scale-up during the early phase of a pandemic. Based on the multi-faceted discussions, we outline 10 key steps to an improved and equitable pandemic response.

ICH S7B In Vitro Assays Do Not Address Mechanisms of QTC Prolongation for Peptides and Proteins - Data in Support of Not Needing Dedicated QTC Studies

Current cardiac safety testing focuses on detecting drug-induced QTC prolongation as a surrogate for risk of Torsade de Pointes. The nonclinical strategy, described in International Conference on Harmonization (ICH) S7B, includes in vitro assessment of hERG block or ventricular repolarization delay and in vivo QT prolongation. Several studies have reported predictive values of ICH S7B results for clinical QTC outcomes for small molecules; none has examined peptides and proteins other than monoclonal antibodies. To address this knowledge gap, information for peptides and proteins submitted to the US Food and Drug Administration (FDA) was collected. Results of hERG assays, ventricular repolarization assays, and in vivo QT assessment were compared with clinical QTC study outcomes. The results show that 14% clinical QTC studies for approved and investigational products failed to exclude 10-ms QTC prolongation. Clinical QTC prolongation for these molecules lacked concentration-dependence which is expected for hERG block-mediated mechanism or QTC prolongation could not be excluded due to characterization in the clinical study. The hERG and ventricular repolarization assays do not identify clinical QTC prolongation potential for peptides and proteins. Lack of alignment between hERG and ventricular repolarization assay results and clinical QTC outcomes suggests that the mechanisms of QTC prolongation by some peptides and proteins are unrelated to direct cardiac ion channel block. Similar to large targeted proteins and monoclonal antibodies, peptides and proteins regardless of size have a low likelihood of direct cardiac ion channel interactions. This characteristic supports waiving the requirement for thorough QT assessment for products comprised of naturally occurring amino acids unless proarrhythmia potential is suggested by nonclinical or clinical data.

Enrichment Benefits of Risk Algorithms for Pulmonary Arterial Hypertension Clinical Trials

Rationale: Event-driven primary endpoints are increasingly used in pulmonary arterial hypertension clinical trials, substantially increasing required sample sizes and trial lengths. The U.S. Food and Drug Administration advocates the use of prognostic enrichment of clinical trials by preselecting a patient population with increased likelihood of experiencing the trial's primary endpoint.Objectives: This study compares validated clinical scales of risk (Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension, the French score, and Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management [REVEAL] 2.0) to identify patients who are likely to experience a clinical worsening event for trial enrichment.Methods: Baseline data from three pulmonary arterial hypertension clinical trials (AMBITION [a Study of First-Line Ambrisentan and Tadalafil Combination Therapy in Subjects with Pulmonary Arterial Hypertension], SERAPHIN [Study of Macitentan on Morbidity and Mortality in Patients with Symptomatic Pulmonary Arterial Hypertension], and GRIPHON [Selexipag in Pulmonary Arterial Hypertension]) were pooled and standardized. Receiver operating curves were used to measure each algorithm's performance in predicting clinical worsening within the pooled placebo cohort. Power simulations were conducted to determine sample size and treatment time reductions for multiple enrichment strategies. A cost analysis was performed to illustrate potential financial savings by applying enrichment to GRIPHON.Measurements and Main Results: All risk algorithms were compared using area under the receiver operating curve and substantially outperformed prediction per New York Heart Association Functional Class. The REVEAL 2.0's risk grouping provided the greatest time and sample size savings in AMBITION and GRIPHON for all enrichment strategies but lacked appropriate inputs (i.e., N-terminal-proB-type natriuretic peptide) to perform as well in SERAPHIN. Cost analysis applied to GRIPHON demonstrated the greatest financial benefit by enrolling patients with a REVEAL score ≥8.Conclusions: This preliminary study demonstrates the feasibility of risk algorithms for pulmonary arterial hypertension trial enrichment and a need for further investigation.

General Principles for the Validation of Proarrhythmia Risk Prediction Models: An Extension of the CiPA In Silico Strategy

This white paper presents principles for validating proarrhythmia risk prediction models for regulatory use as discussed at the In Silico Breakout Session of a Cardiac Safety Research Consortium/Health and Environmental Sciences Institute/US Food and Drug Administration-sponsored Think Tank Meeting on May 22, 2018. The meeting was convened to evaluate the progress in the development of a new cardiac safety paradigm, the Comprehensive in Vitro Proarrhythmia Assay (CiPA). The opinions regarding these principles reflect the collective views of those who participated in the discussion of this topic both at and after the breakout session. Although primarily discussed in the context of in silico models, these principles describe the interface between experimental input and model-based interpretation and are intended to be general enough to be applied to other types of nonclinical models for proarrhythmia assessment. This document was developed with the intention of providing a foundation for more consistency and harmonization in developing and validating different models for proarrhythmia risk prediction using the example of the CiPA paradigm.

Efficacy and Effectiveness Too Trials: Clinical Trial Designs to Generate Evidence on Efficacy and on Effectiveness in Wide Practice

Efficacy trials, designed to gain regulatory marketing approval, evaluate drugs in optimally selected patients under advantageous conditions for relatively short time periods. Effectiveness trials, designed to evaluate use in usual practice, assess treatments among more typical patients in real‐world conditions with longer follow‐up periods. In “efficacy‐to‐effectiveness (E2E) trials,” if the initial efficacy trial component is positive, the trial seamlessly transitions to an effectiveness trial component to efficiently yield both types of evidence. Yet more time could be saved by simultaneously addressing efficacy and effectiveness in an “efficacy and effectiveness too (EE2) trial.” Additionally, hybrids of the E2E and EE2 approaches with differing degrees of overlap of the two components could allow flexibility for specific drug development needs. In planning EE2 trials, each stakeholder's current and future needs, incentives, and perspective must be considered. Although challenging, the ultimate benefits to stakeholders, the health system, and the public should justify this effort.

Clinical trial design and new therapies for pulmonary arterial hypertension

Until 20 years ago the treatment of pulmonary arterial hypertension (PAH) was based on case reports and small series, and was largely ineffectual. As a deeper understanding of the pathogenesis and pathophysiology of PAH evolved over the subsequent two decades, coupled with epidemiological studies defining the clinical and demographic characteristics of the condition, a renewed interest in treatment development emerged through collaborations between international experts, industry and regulatory agencies. These efforts led to the performance of robust, high-quality clinical trials of novel therapies that targeted putative pathogenic pathways, leading to the approval of more than 10 novel therapies that have beneficially impacted both the quality and duration of life. However, our understanding of PAH remains incomplete and there is no cure. Accordingly, efforts are now focused on identifying novel pathogenic pathways that may be targeted, and applying more rigorous clinical trial designs to better define the efficacy of these new potential treatments and their role in the management scheme. This article, prepared by a Task Force comprised of expert clinicians, trialists and regulators, summarises the current state of the art, and provides insight into the opportunities and challenges for identifying and assessing the efficacy and safety of new treatments for this challenging condition.

State of the art and research perspectives in clinical trial design and new therapies for pulmonary arterial hypertensionhttp://ow.ly/VHQ030mfRxc

2017 Cardiovascular and Stroke Endpoint Definitions for Clinical Trials

This publication describes uniform definitions for cardiovascular and stroke outcomes developed by the Standardized Data Collection for Cardiovascular Trials Initiative and the US Food and Drug Administration (FDA). The FDA established the Standardized Data Collection for Cardiovascular Trials Initiative in 2009 to simplify the design and conduct of clinical trials intended to support marketing applications. The writing committee recognizes that these definitions may be used in other types of clinical trials and clinical care processes where appropriate. Use of these definitions at the FDA has enhanced the ability to aggregate data within and across medical product development programs, conduct meta-analyses to evaluate cardiovascular safety, integrate data from multiple trials, and compare effectiveness of drugs and devices. Further study is needed to determine whether prospective data collection using these common definitions improves the design, conduct, and interpretability of the results of clinical trials.

Agents with vasodilator properties in acute heart failure: how to design successful trials

Agents with vasodilator properties (AVDs) are frequently used in the treatment of acute heart failure (AHF). AVDs rapidly reduce preload and afterload, improve left ventricle to aorta and right ventricle to pulmonary artery coupling, and may improve symptoms. Early biomarker changes after AVD administration have suggested potentially beneficial effects on cardiac stretch, vascular tone, and renal function. AVDs that reduce haemodynamic congestion without causing hypoperfusion might be effective in preventing worsening organ dysfunction. Existing AVDs have been associated with different results on outcomes in randomized clinical trials, and observational studies have suggested that AVDs may be associated with a clinical outcome benefit. Lessons have been learned from past AVD trials in AHF regarding preventing hypotension, selecting the optimal endpoint, refining dyspnoea measurements, and achieving early randomization and treatment initiation. These lessons have been applied to the design of ongoing pivotal clinical trials, which aim to ascertain if AVDs improve clinical outcomes. The developing body of evidence suggests that AVDs may be a clinically effective therapy to reduce symptoms, but more importantly to prevent end-organ damage and improve clinical outcomes for specific patients with AHF. The results of ongoing trials will provide more clarity on the role of AVDs in the treatment of AHF.

Site selection in global clinical trials in patients hospitalized for heart failure: perceived problems and potential solutions

There are over 1 million hospitalizations for heart failure (HF) annually in the United States alone, and a similar number has been reported in Europe. Recent clinical trials investigating novel therapies in patients with hospitalized HF (HHF) have been negative, and the post-discharge event rate remains unacceptably high. The lack of success with HHF trials stem from problems with understanding the study drug, matching the drug to the appropriate HF subgroup, and study execution. Related to the concept of study execution is the importance of including appropriate study sites in HHF trials. Often overlooked issues include consideration of the geographic region and the number of patients enrolled at each study center. Marked differences in baseline patient co-morbidities, serum biomarkers, treatment utilization and outcomes have been demonstrated across geographic regions. Furthermore, patients from sites with low recruitment may have worse outcomes compared to sites with higher enrollment patterns. Consequently, sites with poor trial enrollment may influence key patient end points and likely do not justify the costs of site training and maintenance. Accordingly, there is an unmet need to develop strategies to identify the right study sites that have acceptable patient quantity and quality. Potential approaches include, but are not limited to, establishing a pre-trial registry, developing site performance metrics, identifying a local regionally involved leader and bolstering recruitment incentives. This manuscript summarizes the roundtable discussion hosted by the Food and Drug Administration between members of academia, the National Institutes of Health, industry partners, contract research organizations and academic research organizations on the importance of selecting optimal sites for successful trials in HHF.

Clinical outcome endpoints in heart failure trials: a European Society of Cardiology Heart Failure Association consensus document

Endpoint selection is a critically important step in clinical trial design. It poses major challenges for investigators, regulators, and study sponsors, and it also has important clinical and practical implications for physicians and patients. Clinical outcomes of interest in heart failure trials include all-cause mortality, cause-specific mortality, relevant non-fatal morbidity (e.g., all-cause and cause-specific hospitalization), composites capturing both morbidity and mortality, safety, symptoms, functional capacity, and patient-reported outcomes. Each of these endpoints has strengths and weaknesses that create controversies regarding which is most appropriate in terms of clinical importance, sensitivity, reliability, and consistency. Not surprisingly, a lack of consensus exists within the scientific community regarding the optimal endpoint(s) for both acute and chronic heart failure trials. In an effort to address these issues, the Heart Failure Association of the European Society of Cardiology (HFA-ESC) convened a group of expert heart failure clinical investigators, biostatisticians, regulators, and pharmaceutical industry scientists (Nice, France, 12-13 February 2012) to evaluate the challenges of defining heart failure endpoints in clinical trials and to develop a consensus framework. This report summarizes the group's recommendations for achieving common views on heart failure endpoints in clinical trials.

Do we need to adjudicate major clinical events?

PURPOSE

The use of centralized systems to adjudicate clinical events is common in large clinical trials, in spite of relatively little published literature concerning the rationale and justification. The purpose of this manuscript is to review the reasons for central adjudication and to discuss whether trials could be simplified by limiting or streamlining the adjudication process.

METHODS

We reviewed the literature concerning central adjudication and documented the experience of adjudication in several clinical trials. Since definitions for nonfatal events are generally heterogeneous and subjective, one reason for a central process of adjudication is to assist in assuring systematic application of the definition used in the trial. In open-label trials, assuring that the adjudication is done blinded to treatment assignment may provide protection against differential misclassification. Regulatory authorities, including the FDA, derive confidence in the validity of results when central adjudication is performed. The clinical community has become accustomed to a certain amount of adjudication and may criticize trials that lack adjudication.

LIMITATIONS

It is difficult to document the value of adjudication in trials that have reported adjudicated and nonadjudicated event rates and related treatment effects. Making rationale decisions about when and how to adjudicate is hampered by the lack of published study of when and how central adjudication is helpful to improve the quality and validity of trials and at what cost.

CONCLUSIONS

Adjudication has not been shown to improve the ability to determine treatment effects. Thus, adjudication may be overly complex and overused in many large simple trials. The appropriate role of central adjudication - which trials, which outcomes, what methods - deserves scrutiny and further study.

BiDil for heart failure in black patients: The U.S. Food and Drug Administration perspective

Critics of the U.S. Food and Drug Administration (FDA) approval of the fixed combination of hydralazine hydrochloride, 37.5 mg, and isosorbide dinitrate, 20 mg, for treating heart failure in black patients have suggested that data were insufficient to distinguish treatment effects in black and white people; that distinctions based on race, rather than pathophysiology, were scientifically unreasonable; and that a "race-based" approval could be a commercial ploy to avoid a more expensive and prolonged full evaluation of a drug. The criticisms acknowledge that data supporting the approval came from a well-designed clinical trial in which self-identified black patients with heart failure who took hydralazine hydrochloride-isosorbide dinitrate with standard therapy experienced a statistically significant 43% (95% CI, 11% to 63%) reduction in mortality compared with those who took only the standard therapy. The criticisms do not always recognize that the decision to conduct the trial in only black patients reflected careful analyses of 2 previous trials in racially mixed patient populations that compared hydralazine hydrochloride-isosorbide dinitrate with placebo or with enalapril. Both trials showed little or no overall effect of hydralazine hydrochloride-isosorbide dinitrate in the mostly white patient population but hinted at a substantial effect in subsets of black patients. Perhaps most critically, the criticisms do not appreciate the urgency of strong scientific evidence of a substantial survival benefit in black patients. A serious attempt to avoid race-based approval by mandating study of a mixed population to identify a possible white patient-responder subset, particularly without a plausible hypothesis as to what that subset might be, would have required years of work, many thousands of patients, and wholly unreasonable delay in approval of a treatment whose effectiveness had been well-documented in the group for which it was intended.

Regional properties of calcium entry in barnacle neurons determined with Arsenazo III and a photodiode array

Calcium changes were simultaneously measured at many positions on individual neurons from the supraesophageal ganglion of the barnacle by detecting absorbance changes of the indicator dye Arsenazo III with a 10 X 10 photodiode array. These changes were correlated with positions on the stimulated cell determined from Lucifer yellow injections. Absorbance signals were found at all locations on the cells, demonstrating that calcium channels were distributed on the somata, axons, and neuropil processes. By comparing the amplitude of the signal with the membrane area in each region, we could measure the calcium entry per impulse per unit of surface in each part of the cell. Assuming that the properties of the calcium channels are the same in all regions, we determined that calcium channels were distributed uniformly along the commissural axon of one cell and were found at higher density in the neuropil. Because significant calcium changes are only detected when cells are depolarized above about -20 mV, the presence of absorbance signals indicates membrane depolarization above this level. We used this fact to show that calcium spikes propagate along the axon and into the neuropil of one cell, along the axon of another, and not at all in a third. Differences in time course of calcium transients were observed in different regions of cells. The recovery time course was faster at the edge of the cell body than in the center and faster in the neuropil than in the axon or soma. During trains of action potentials or during wide action potentials in tetraethylammonium (TEA) saline, the calcium signal reached a plateau in the neuropil while continuing to rise in the axon and soma.