Pragmatic trial design elements showed a different impact on trial interpretation and feasibility than explanatory elements

The Evolution of Drug Regulatory Sciences in the Netherlands: More than a Country Report

In the Netherlands, drug regulatory science is a vibrant national and internationally oriented community. In this review, we present the factors that have contributed to this successful collaboration between relevant stakeholders and that led to a surge of activities around how regulatory science became embedded in the ecosystem of medicines research, clinical pharmacology, policymaking and regulation. We distinguished three pivotal episodes: (i) TI Pharma Escher-project, (ii) Dutch Medicines Evaluation Board as catalyst of the big jump, and (iii) Regulatory Science Network Netherlands and multistakeholder engagement. The research agenda has been influenced by the dynamic evolution of legal frameworks in Europe, such as the EU orphan medicines legislation of 2001 and the EU pharmacovigilance legislation of 2012. All these developments have inspired and have raised pertinent regulatory sciences questions. Furthermore, clinical pharmacology as a discipline has been very influential in shaping regulatory science, contributing to discussions on the level of clinical evidence that is necessary to justify marketing approval of a new medicine. With a growing interest of multiple parties such as academics, European Medicines Agency, national agencies, patient organizations and EFPIA, connecting regulatory science activities is key.

A novel pivot ankle/foot prosthesis reduces sound side loading and risk for osteoarthritis: a pragmatic randomized controlled trial

BACKGROUND

Individuals with unilateral transtibial amputation are at risk of abnormal mechanical joint loading and development of osteoarthritis on sound side joint structures.

OBJECTIVES

This study describes the spatiotemporal and kinetic and kinematic parameters related to osteoarthritis in participants while using (A) a solid-ankle cushioned-heel prosthesis (SACH), (B) a conventional energy storage and return (ESAR) foot prosthesis, and (C) a novel ESAR (N-ESAR) foot prosthesis.

STUDY DESIGN

A pragmatic randomized controlled trial.

METHODS

K3-K4 ambulators used three feet in a 2-week randomized cross-over order. Kinetics of vertical ground reaction forces (vGRFs) and 3D kinematics of joint angles were integrated to provide normalized parameters. Data were analyzed using one way and mixed model Analysis of variance (ANOVAs) (p < 0.05) and Cohen d statistic.

RESULTS

Twenty participants, aged 40 ± 16 years with body mass index of 24.7 ± 3.6 kg/m2, experienced minimal change in the spatiotemporal parameters between feet. Participants using the N-ESAR foot prosthesis experienced reduced peak knee external adduction moment (p = 0.030), peak vGRFs (p < 0.001), and peak loading rate of vGRFs (p = 0.030). Peak knee flexion moments only changed when using the solid-ankle cushioned-heel prosthesis, in a positive direction (p = 0.014). Using the N-ESAR prosthesis also increased peak distal shank power during late stance phase (p < 0.001).

CONCLUSIONS

A novel ankle/foot ESAR prosthesis reduces loading on the sound side. With extended use of the N-ESAR foot prosthesis, these findings may provide the prosthesis user with improved outcomes related to sound side loading and development of osteoarthritis.

Assessment of the implementation context in preparation for a clinical study of machine-learning algorithms to automate the classification of digital cervical images for cervical cancer screening in resource-constrained settings

Introduction

We assessed the implementation context and image quality in preparation for a clinical study evaluating the effectiveness of automated visual assessment devices within cervical cancer screening of women living without and with HIV.

Methods

We developed a semi-structured questionnaire based on three Consolidated Framework for Implementation Research (CFIR) domains; intervention characteristics, inner setting, and process, in Cape Town, South Africa. Between December 1, 2020, and August 6, 2021, we evaluated two devices: MobileODT handheld colposcope; and a commercially-available cell phone (Samsung A21ST). Colposcopists visually inspected cervical images for technical adequacy. Descriptive analyses were tabulated for quantitative variables, and narrative responses were summarized in the text.

Results

Two colposcopists described the devices as easy to operate, without data loss. The clinical workspace and gynecological workflow were modified to incorporate devices and manage images. Providers believed either device would likely perform better than cytology under most circumstances unless the squamocolumnar junction (SCJ) were not visible, in which case cytology was expected to be better. Image quality (N = 75) from the MobileODT device and cell phone was comparable in terms of achieving good focus (81% vs. 84%), obtaining visibility of the squamous columnar junction (88% vs. 97%), avoiding occlusion (79% vs. 87%), and detection of lesion and range of lesion includes the upper limit (63% vs. 53%) but differed in taking photographs free of glare (100% vs. 24%).

Conclusion

Novel application of the CFIR early in the conduct of the clinical study, including assessment of image quality, highlight real-world factors about intervention characteristics, inner clinical setting, and workflow process that may affect both the clinical study findings and ultimate pace of translating to clinical practice. The application and augmentation of the CFIR in this study context highlighted adaptations needed for the framework to better measure factors relevant to implementing digital interventions.

Lessons learned from conducting a pragmatic, randomized, crossover trial on robot-assisted gait training in children with cerebral palsy (PeLoGAIT)

PURPOSE

To investigate the effectiveness of outpatient robot-assisted gait training (RAGT) in ambulatory children with spastic cerebral palsy.

METHODS

Children were randomized to two different intervention sequences within a pragmatic crossover design. They performed five weeks of RAGT (3 sessions per week) and five weeks of usual care (UC). Dimension E of the Gross Motor Function Measure-88 (GMFM E) as the primary outcome as well as Dimension D (GMFM D), and timed walking tests were assessed before and after each treatment sequence and after a 5-week follow-up.

RESULTS

The trial was stopped early because of recruitment problems. We included 16 children with a mean age of 11.3 years (6.0-15.3 years). GMFM E median (IQR) change scores were -0.7 (-2.8 to 3.5) after RAGT and 0 (-2.4 to 2.4) after UC. Neither GMFM E nor any secondary outcome measure changed significantly after RAGT or UC, nor were any period, follow-up, or carry-over effects observable.

CONCLUSIONS

RAGT as a single intervention was not effective in improving walking abilities in the included children. It should be embedded in a holistic treatment approach, as it cannot cover all aspects relevant to gait. Furthermore, children's personalized rehabilitation goals should be carefully monitored with individualized measurement instruments.

An analysis reveals differences between pragmatic and explanatory diagnostic accuracy studies

OBJECTIVES

The objective of this study was to clarify a difference between two approaches while evaluating the diagnostic accuracy of medical tests, labeled here as "pragmatic" vs. "explanatory" studies.

METHODS

Using the definitions and characteristics described by Schwartz and Lellouch for randomized trials of interventions, and Schwartz' more general distinction between a pragmatic and an explanatory approach in medical research, we define a similar continuum for diagnostic accuracy studies. Explanatory studies aim to better understand the behavior of a test; pragmatic ones are done to support recommendations or decisions about using the test in clinical practice.

RESULTS

Pragmatic test accuracy studies differ from explanatory test accuracy studies in several ways. The difference in aims has implications for key elements of study design, such as the study eligibility criteria, the recruitment of patients, the reference standard, and the choice of the statistical analysis. Explanatory accuracy studies are often designed to test a hypothesis. They are typically selective in recruitment, may include "healthy controls," with a small sample size, often recruited at a single center. They ignore testing failures in the analysis and more often present their results as ROC curves. By contrast, pragmatic studies are designed to guide decision making. They ideally will recruit a single, large, and representative group of patients at multiple sites and will more often present their results as estimates of sensitivity and specificity or predictive values at a prespecified threshold.

CONCLUSION

Distinguishing between a pragmatic and an explanatory approach can help in the design, analysis, and interpretation of diagnostic accuracy studies. It can clarify debates about the appropriateness of design features to the study purpose and about the validity and applicability of study findings.

Patient-specific devices and population-level evidence: evaluating therapeutic interventions with inherent variation

Designing and manufacturing medical devices for specific patients is becoming increasingly feasible with developments in 3D printing and 3D imaging software. This raises the question of how patient-specific devices can be evaluated, since our 'gold standard' method for evaluation, the randomised controlled trial (RCT), requires that an intervention is standardised across a number of individuals in an experimental group. I distinguish several senses of patient-specific device, and focus the discussion on understanding the problem of variations between instances of an intervention for RCT evaluation. I argue that, despite initial appearances, it is theoretically possible to use RCTs to evaluate some patient-specific medical devices. However, the argument reveals significant difficulties for ensuring the validity of such trials, with implications for how we should think about methods of evidence gathering and regulatory approaches for these technologies.

Series: Pragmatic trials and real world evidence: Paper 3. Patient selection challenges and consequences

This paper addresses challenges of identifying, enrolling, and retaining participants in a trial conducted within a routine care setting. All patients who are potential candidates for the treatments in routine clinical practice should be considered eligible for a pragmatic trial. To ensure generalizability, the recruited sample should have a similar distribution of the treatment effect modifiers as the target population. In practice, this can be best achieved by including-within the selected sites-all patients without further selection. If relevant heterogeneity between subgroups is expected, increasing the relative proportion of the subgroup of patients in the heterogeneous trial could be considered (oversampling) or a separate trial in this subgroup can be planned. Selection will nevertheless occur. Low enrollment and loss to follow-up can introduce selection and can jeopardize validity as well as generalizability. Pragmatic trials are conducted in clinical practice rather than in a dedicated research setting, which could reduce recruitment rates. However, if a trial poses a minimal burden to the physician and the patient and routine clinical practice is maximally adhered to, the participation rate may be high and loss to follow-up will not be a specific problem for pragmatic trials.