Randomized clinical trials with run-in periods: frequency, characteristics and reporting

Uncertainty in the estimated effects of statin initiation on risk of dementia: using a multiverse analysis to assess sources of variability

Mixed evidence on how statins affect dementia risk may reflect variability in model specifications. Alternate specifications are rarely systematically compared. Using an emulated trial design framework, we investigated variation in the estimated effect of statin initiation on dementia across alternative (1) eligibility criteria, (2) confounding variable sets, and (3) outcome definitions. Kaiser Permanente Northern California members' linked electronic health records from 1996 to 2020 were used to identify statin initiation and dementia diagnoses. Statin initiators were matched on age and low-density lipoprotein cholesterol with up to 5 non-initiators. Possible covariates included clinical (n = 1.4 million); socioeconomic and behavioral (n = 265,224); and genetic (n = 69,573) variables. Using Cox proportional-hazards models, we estimated variation across 1.27 million intent-to-treat estimates for statin initiation varying specification of eligibility, outcome definition, and covariates. Estimated hazard ratios (HRs) for statin initiation on dementia across all specifications ranged from 0.93 to 1.47. The variance of estimates due to model specification differences was 7.6 times larger than the average variance of specific estimates due to finite sample size. Three modeling decisions notably attenuated coefficients [ln(HR)]: requiring a run-in period prior to the emulated trial start date (0.034); adjustment for diabetes (0.030) and cardiovascular disease (0.039); and excluding the first year of follow-up (0.041). HRs from models with all three specifications ranged from 0.99 to 1.15. No specification we evaluated consistently generated protective effects. Estimates of the association between statin initiation and dementia leveraging real world data are sensitive to model specification, especially decisions related to clinical covariates and time-at-risk.

Placebo nonresponders: An experimental investigation on their unreliability over time

In order to disentangle the effects of drugs from placebo responses, several approaches have been used, such as a placebo run-in phase in which only placebo nonresponders, or poor responders, are considered for further randomization to either placebo or active treatment. This study is aimed at investigating the variability of placebo nonresponders obtained through the classical placebo run-in paradigm (group RUN) and through mismatch conditioning (group MIS), as done in our previous study. To do this, we simulated a real clinical trial in the laboratory, in which the placebo responders of both groups were discarded and the remaining nonresponders of both groups RUN and MIS were randomized to either continuing on placebo (groups RUN-P and MIS-P, respectively) or receiving topical 0.5% lidocaine (groups RUN-L and MIS-L, respectively) applied to the skin. By measuring pain thresholds, we found that the placebo nonresponders selected on the first day of the experiment showed different responses on the following day in both group RUN and MIS. This led to no significant differences between placebo and lidocaine in both groups. Although this is an experimental laboratory situation far from the clinical trial setting, these findings show that placebo nonresponders are not necessarily constant over time, both when a placebo run-in protocol is used and when nonresponders are created in the laboratory. This questions the reliability of selecting placebo nonresponders as a methodological approach in clinical research. Therefore, we suggest reconsidering the validity and usefulness of placebo run-in protocols. PERSPECTIVE: Placebo nonresponders are sometime selected for further randomization to either placebo or active treatment. In this experimental study, which is a laboratory simulation of a clinical trial, we found that placebo nonresponders vary from day to day, thus questioning their validity as a methodological approach in clinical research.

Run-in periods and treatment outcomes in asthma trials: A narrative review

Background

The run-in period is an important element of randomized controlled trials, and is often used in respiratory disease trials. The design of the run-in period can greatly impact results and data interpretation, and as such should be designed carefully.

Methods

In this review, we describe the design of run-in periods across six phase 3A trials of triple therapy in asthma, and discuss how differences in run-in period design (specifically the duration, treatment, and reporting of run-in results) may have the potential to alter the interpretation of study outcomes.

Results

We found that the duration of run-in periods ranged between 2 and 7 weeks, with some studies including a combination of screening, run-in and stabilization periods, and others including a run-in period only. Run-in treatment also varied, with some studies running in patients on their previous inhaled corticosteroid/long-acting β2-agonist (ICS/LABA) therapy, and others harmonizing treatment by switching to the same ICS/LABA combination used in the on-treatment phase, or a different ICS/LABA combination entirely. Most of the studies included did not report any changes to study outcomes seen prior to randomization.

Conclusion

We discuss the potential implications associated with the various trial designs, and propose that run-in periods should be consciously designed to meet the goals of the specific study. We also propose that standardized reporting of run-in changes would further allow for differentiation between improvements due to improved adherence and true treatment benefits, and aid with comparing data from different clinical trials.

Recommendations for Designing, Conducting, and Reporting Feeding Trials in Nutrition Research

Double-blind, placebo-controlled, randomized controlled trials are the gold standard for clinical trials in nutrition science. For trials of whole diets, dietary counseling is advantageous as they offer clinical translatability although can vary in the fidelity of the intended intervention from participant to participant and across studies. Feeding trials, in which most or all food is provided, offer high precision and can provide proof-of-concept evidence that a dietary intervention is efficacious and can also better evaluate the effect of known quantities of foods and nutrients on physiology. However, they come with additional methodological complexities. Feeding trials also call for a variety of unique methodological considerations, not least of which relate to the design and delivery of diets to participants. This review aims to provide a comprehensive summary of recommendations for design and conduct of feeding trials, encompassing domiciled and nondomiciled feeding trials. Several pertinent aspects of trial design and methodology are discussed, including defining the study population to maximize retention, safety, and generalizability of findings, recommendations for design of control interventions and optimizing blinding, and specific considerations for clinical populations. A detailed stepwise process for menu design, development, validation, and delivery are also presented. These recommendations aim to facilitate methodologic consistency and execution of high-quality feeding trials, ultimately facilitating improved understanding of the role of diet in treating disease and the underpinning mechanisms.

Exercise and QUality Diet after Leukemia: A Randomized Weight Loss Trial among Adult Survivors of Childhood Leukemia in the Childhood Cancer Survivor Study

BACKGROUND

Obesity is prevalent in childhood cancer survivors and interacts with cancer treatments to potentiate risk for cardiovascular (CV) death. We tested a remote weight-loss intervention trial that was effective among adults with CV risk factors in a cohort of adult survivors of childhood acute lymphoblastic leukemia (ALL) with overweight/obesity.

METHODS

In this phase III efficacy trial, survivors of ALL enrolled in the Childhood Cancer Survivor Study with a body mass index ≥25 kg/m2 were randomized to a remotely delivered weight-loss intervention versus self-directed weight loss, stratified by history of cranial radiotherapy. The primary endpoint was the difference in weight loss at 24 months in an intent-to-treat analysis. Analyses were performed using linear mixed-effects models.

RESULTS

Among 358 survivors (59% female; median attained age: 37 years; IQR: 33-43 years), the baseline mean (SD) weight was 98.6 kg (24.0) for the intervention group (n = 181) and 94.9 kg (20.3) for controls (n = 177). Adherence to the intervention was poor; 15% of individuals in the intervention group completed 24/30 planned coaching calls. Weight at 24 months was available for 274 (77%) participants. After controlling for cranial radiotherapy, sex, race/ethnicity, and age, the mean (SE) change in weight from baseline to 24 months was -0.4 kg (0.8) for the intervention group and 0.2 kg (0.6) for control participants (P = 0.59).

CONCLUSIONS

A remote weight-loss intervention that was successful among adults with CV conditions did not result in significant weight loss among adult survivors of childhood ALL.

IMPACT

Future interventions in this population must be tailored to the unique needs of survivors to encourage engagement and adherence. See related In the Spotlight, p. 1147.

The efficacy of the TEACH e-Learning course at improving early childhood educators' physical activity and sedentary behaviour self-efficacy, knowledge, intentions, and perceived behavioural control: a randomized controlled trial

BACKGROUND

Early childhood educators play a critical role in promoting physical activity and reducing sedentary time in childcare centres. However, early childhood educators receive limited specialised pre- and in-service learning opportunities relating to these behaviours and may lack the capacity to effectively engage children in healthy movement behaviours. This study aimed to examine the efficacy of an e-Learning course on increasing early childhood educators' physical activity and sedentary behaviour-related capacities.

METHODS

A two-group parallel randomized controlled trial was conducted with early childhood educators in Canada (Mage = 41.78, 97% female). Participants randomized to the intervention group were asked to complete a physical activity and sedentary behaviour e-Learning course within a 4-week period. Participants randomized to the waitlist control condition were assigned to a waitlist to receive the intervention after the testing period. Participants reported on their self-efficacy, knowledge, intentions, and perceived behavioural control relating to physical activity and sedentary behaviours at baseline, post-intervention, and 3 months follow-up. Linear mixed effects models were estimated to determine difference in changes in outcomes from baseline to post-intervention, and follow-up.

RESULTS

A total of 209 early childhood educators participated in the study (intervention n = 98; control n = 111). The TEACH e-Learning course was found to be efficacious at improving all of the examined outcomes, with standardized effect sizes ranging from d = 0.58 to d = 0.65 for self-efficacy outcomes, d = 0.66 to d = 1.20 for knowledge outcomes, d = 0.50 to d = 0.65 for intention outcomes, and d = 0.33 to d = 0.69 for perceived behavioural control outcomes post-intervention. The intervention effects were sustained at follow-up for all outcomes apart from perceived behavioural control to limit screen time. Additionally, the magnitude of the effect for knowledge outcomes decreased at follow-up, with standardized effect sizes ranging from d = 0.49 to d = 0.67.

CONCLUSIONS

The e-Learning course was highly successful at improving early childhood educators' capacity pertaining to physical activity and sedentary behaviours. Providing training content through e-Learning may be an efficacious approach to providing continual professional learning opportunities relating to physical activity and sedentary time to early childhood educators on a large scale.

Dual glucagon-like peptide-1 and glucagon receptor agonism reduces energy intake in type 2 diabetes with obesity

AIMS

To establish which components of energy balance mediate the clinically significant weight loss demonstrated with use of cotadutide, a glucagon-like peptide-1 (GLP-1)/glucagon receptor dual agonist, in early-phase studies.

MATERIALS AND METHODS

We conducted a phase 2a, single-centre, randomized, placebo-controlled trial in overweight and obese adults with type 2 diabetes. Following a 16-day single-blind placebo run-in, participants were randomized 2:1 to double-blind 42-day subcutaneous treatment with cotadutide (100-300 μg daily) or placebo. The primary outcome was percentage weight change. Secondary outcomes included change in energy intake (EI) and energy expenditure (EE).

RESULTS

A total of 12 participants (63%) in the cotadutide group and seven (78%) in the placebo group completed the study. The mean (90% confidence interval [CI]) weight change was -4.0% (-4.9%, -3.1%) and -1.4% (-2.7%, -0.1%) for the cotadutide and placebo groups, respectively (p = 0.011). EI was lower with cotadutide versus placebo (-41.3% [-66.7, -15.9]; p = 0.011). Difference in EE (per kJ/kg lean body mass) for cotadutide versus placebo was 1.0% (90% CI -8.4, 10.4; p = 0.784), assessed by doubly labelled water, and -6.5% (90% CI -9.3, -3.7; p < 0.001), assessed by indirect calorimetry.

CONCLUSION

Weight loss with cotadutide is primarily driven by reduced EI, with relatively small compensatory changes in EE.

Observational studies to emulate randomized trials: Some real-world barriers

The randomized controlled trial (RCT) forms the basis for drug approval by regulatory agencies. Observational studies using existing data from healthcare databases now also provide real-world evidence (RWE) in regulatory decision-making. Several initiatives are assessing the value of RWE by conducting observational studies that emulate published RCTs. While many RCTs are straightforward to emulate, others are challenging. We describe three RCT design aspects that pose challenges for observational studies. First are trials that enrol already treated subjects who must discontinue these treatments at the time of randomization, which can distort the comparison with observational studies. Second is the inclusion of a run-in phase, especially to exclude non-compliant subjects from the trial. Third are trials that evaluate the effect of weaning off treatment. In conclusion, future randomized trials that aim to be emulated by observational studies could consider study designs that allow emulation and thus provide valid and complementary RWE.

Creating Placebo Nonresponders in the Lab

Conditioning and expectation are known to be the main mechanisms of placebo analgesia. They may operate together, so that expectations may be enhanced by a conditioning procedure. Although most of the studies have tried to potentiate expectations through conditioning in order to generate good placebo responders, a few studies have tried to mismatch conditioning and expectations in order to investigate the subsequent administration of a placebo. In this study, we want to further investigate this mismatch. We generated incongruent associations during a conditioning procedure in which the study participants did not get what they expected. In fact, although the participants received verbal instructions of pain decrease following the administration of a placebo, we surreptitiously increased the painful electric stimulation. Two pairings of these incongruent associations (mismatch between what was expected and what was experienced) disrupted expectations of analgesia as well as the placebo effect, as assessed by measuring electric pain thresholds on the hand. The effects of mismatch conditioning on the hand extended to the contralateral arm and to a different type of pain (tourniquet), which suggests that local mismatch conditioning may affect the whole body. In all cases, expectations predicted placebo analgesia. These findings indicate that placebo nonresponders can be created in the laboratory by acting on expectations and that local effects can be generalized to other parts of the body. They also stress the importance of expectations in the therapeutic outcome, with important implications for clinical trials. PERSPECTIVE: By using mismatch conditioning, in which study participants did not get what they expected, we reduced expectations of analgesia, and this reduction abolished placebo analgesia. This effect extended to other parts of the body and other types of pain, which indicates that placebo nonresponders can be created in the laboratory.

Effect of E-PR-01 on non-specific low back pain in the adult population: A randomized, double-blind, placebo-controlled, parallel-group trial

BACKGROUND

Low back pain (LBP) has emerged as a major public health concern leading to significant work productivity loss and deterioration in the quality of life.

OBJECTIVE

A randomized, double-blind, placebo-controlled parallel-group clinical trial was conducted to investigate the effect of E-PR-01, a proprietary blend of Vitex negundo leaves and zingiber officinale rhizome, in individuals with LBP.

METHODS

Seventy-two individuals aged 18 to 60 years with LBP were randomized in a 1:1 ratio in either the E-PR-01 or placebo group. The participants were instructed to take 2 capsules/day of the study products in two divided doses for 30 days. The study outcomes were changes in functional activity, bending flexibility, pain intensity, work productivity, and sleep quality. The sustained effect of the study products was also evaluated on the pain and physical functioning for 7 days after stopping the product intake. The product's safety was evaluated by adverse events reporting throughout the study.

RESULTS

Compared to the placebo, the E-PR-01 demonstrated a statistically significant reduction in functional disability (mean RMQ score: -5.47 vs. -2.48), pain intensity (mean VAS score: -31.29 vs. -14.55) and improved bending flexibility (mean distance: -5.60 vs. -2.38 cm). In addition, a significant improvement in work productivity as well as sleep quality was also observed. In the E-PR-01 group, a statistically significant sustained effect was observed compared to the placebo for the pain intensity (p< 0.0005) and the functional activity (p< 0.0001) scores. No significant adverse event was reported in the study.

CONCLUSION

E-PR-01 significantly improved low back pain and bending flexibility in adults without adverse effects. Moreover, the effect of E-PR-01 lasted 7 days after stopping the intervention.

Sociodemographic predictors of successful screening and subsequent randomization in a digital health hypertension intervention

Introduction

Clinical trials often enroll nonrepresentative participant samples, limiting generalizability of trial findings. The current analysis explores the influences of remote recruitment and screening protocols on participation in a digital health intervention (DHI) to promote the evidence-based Dietary Approaches to Stop Hypertension (DASH) eating pattern.

Methods

Nourish was a 12-month randomized controlled trial comparing the effectiveness of a DHI to an attention control arm among US adults with hypertension. Participants were recruited using digital approaches; eligible individuals completed several screening steps. We examined associations between sociodemographics and mobile technology use and completion of each screening step and compared those characteristics between randomized and nonrandomized participants (those consented but were screened out before randomization).

Results

A total of 678 adults consented to participate in Nourish; 44% of those consented were randomized (n = 301). Those randomized possessed a higher education level (p < 0.0001); were more likely to use health-related apps (p < 0.0001) and wearables (p < 0.0001); and were older (p = 0.01) than nonrandomized individuals. Randomized adults were more likely to use a desktop/laptop/tablet for Internet access (vs mobile phones) (p = 0.01). No significant association was observed existed between sex, race, ethnicity, income, or geographic density of residence and subsequent randomization.

Conclusions

Participants with lower education levels or limited experience in using mobile technologies may require additional support to participate in DHIs. Future research is needed to evaluate remote clinical trial procedures and impacts on generalizability to achieve equitable clinical trial participation.

An Updated Review on the Role of Non-dihydropyridine Calcium Channel Blockers and Beta-blockers in Atrial Fibrillation and Acute Decompensated Heart Failure: Evidence and Gaps

PURPOSE

The 2021 European Society of Cardiology guidelines on acute and chronic heart failure (HF) recommend that non-dihydropyridine calcium channel blockers (NDCC) should be avoided in patients with HF with reduced ejection fraction. It also emphasizes that beta-blockers only be initiated in clinically stable, euvolemic patients. Despite these recommendations, NDCC and beta-blockers are often still employed in patients with AF with rapid ventricular response and acute decompensated HF. The relative safety and efficacy of these therapies in this setting is unclear.

METHODS

To address the question of the safety and efficacy of NDCC and beta-blockers for acute rate control in decompensated HF, we provide a perspective on the literature of NDCC and beta-blockers in chronic HF with reduced and preserved ejection fraction and AF, including trials on the management of AF with rapid ventricular response with and without HF.

RESULTS

Robust data demonstrates mortality benefits when beta-blockers are used in patients with chronic HF with reduced ejection fraction. The data that inform the contraindication of NDCC in HF with reduced ejection fraction are outdated and were not primarily designed to address the efficacy and safety of rate control of AF in patients with HF. Several studies indicate that for acute rate control, NDCC and beta-blockers are both efficacious therapies, especially in the setting of tachycardia-induced cardiomyopathy.

CONCLUSION

Future studies are needed to assess the safety and efficacy of beta-blockers and NDCC in both acute and chronic AF with HF with reduced and preserved ejection fraction.

Designs used in published therapeutic studies of rare superficial vascular anomalies: a systematic literature search

BACKGROUND

Rare superficial vascular anomalies represent a wide range of diseases. Their management is difficult given the broad spectrum and the lack of clinical trials assessing treatment efficacy. A randomized clinical trial of vascular anomalies is difficult because of the rarity of the diseases and is enhanced by the population of interest often being children. Therefore, suitable designs are needed. We conducted a methodological systematic literature search to identify designs implemented for investigating the treatment of rare superficial vascular anomalies.

METHODS

We conducted a literature search on January 25, 2021, of the PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, ClinicalTrials.gov and European Union Clinical Trials Register databases. This systematic methodological literature search was registered at the Prospective Register of Systematic Reviews (PROSPERO: CRD42021232449). Randomized and non-randomized studies were included if they met the following criteria: were prospective studies of rare superficial vascular anomaly therapies, dealt with humans (adults and children) and were published in English from 2000. We excluded case reports/case series reporting fewer than 10 patients, reviews, retrospective studies, animal studies, studies of systemic or common vascular anomalies and non-therapeutic studies. We did not assess risk of bias in the included studies because our review was a methodological one focused on the design used. The review provided a descriptive analysis of relevant features of eligible research studies.

RESULTS

From 2046 articles identified, we included 97 studies (62 reports and 35 ongoing studies): 25 randomized controlled studies, 7 non-randomized comparative studies, 64 prospective cohorts and 1 case series. Among the 32 comparative studies included, 21 used a parallel-group design. The 11 other studies used different designs such as cross-over, randomized placebo phase, delayed-start, within-person, or challenge-dechallenge-rechallenge or used a historical control group or an observational run-in period.

CONCLUSIONS

Our systematic literature search highlights the lack of randomized control trials in superficial vascular anomalies due to the rarity of patients and their heterogeneity. New designs are emerging and can overcome the limitations of testing treatments in parallel groups.

Core protocol development for phase 2/3 clinical trials in the leukodystrophy vanishing white matter: a consensus statement by the VWM consortium and patient advocates

BACKGROUND

The leukodystrophy "Vanishing White Matter" (VWM) is an orphan disease with neurological decline and high mortality. Currently, VWM has no approved treatments, but advances in understanding pathophysiology have led to identification of promising therapies. Several investigational medicinal products are either in or about to enter clinical trial phase. Clinical trials in VWM pose serious challenges, as VWM has an episodic disease course; disease phenotype is highly heterogeneous and predictable only for early onset; and study power is limited by the small patient numbers. To address these challenges and accelerate therapy delivery, the VWM Consortium, a group of academic clinicians with expertise in VWM, decided to develop a core protocol to function as a template for trials, to improve trial design and facilitate sharing of control data, while permitting flexibility regarding other trial details. Overall aims of the core protocol are to collect safety, tolerability, and efficacy data for treatment assessment and marketing authorization.

METHODS

To develop the core protocol, the VWM Consortium designated a committee, including clinician members of the VWM Consortium, family and patient group advocates, and experts in statistics, clinical trial design and alliancing with industries. We drafted three age-specific protocols, to stratify into more homogeneous patient groups, of ages ≥ 18 years, ≥ 6 to < 18 years and < 6 years. We chose double-blind, randomized, placebo-controlled design for patients aged ≥ 6 years; and open-label non-randomized natural-history-controlled design for patients < 6 years. The protocol describes study populations, age-specific endpoints, inclusion and exclusion criteria, study schedules, sample size determinations, and statistical considerations.

DISCUSSION

The core protocol provides a shared uniformity across trials, enables a pool of shared controls, and reduces the total number of patients necessary per trial, limiting the number of patients on placebo. All VWM clinical trials are suggested to adhere to the core protocol. Other trial components such as choice of primary outcome, pharmacokinetics, pharmacodynamics, and biomarkers are flexible and unconstrained by the core protocol. Each sponsor is responsible for their trial execution, while the control data are handled by a shared research organization. This core protocol benefits the efficiency of parallel and consecutive trials in VWM, and we hope accelerates time to availability of treatments for VWM.

TRIAL REGISTRATION

NA. From a scientific and ethical perspective, it is strongly recommended that all interventional trials using this core protocol are registered in a clinical trial register.

Possible Strategies to Mitigate Placebo or Vehicle Response in Dry Eye Disease Trials: A Narrative Review

Many candidate drugs for dry eye disease (DED) have been assessed over the years in pursuit of demonstrating efficacy in both signs and symptoms. However, patients with DED have very limited treatment options for management of both signs and symptoms of DED. There are several potential reasons behind this including the placebo or vehicle response, which is a frequent issue observed in DED trials. A high magnitude of vehicle response interferes with the estimation of a drug's treatment effect and may lead to failure of a clinical trial. To address these concerns, Tear Film and Ocular Surface Society International Dry Eye Workshop II taskforce has recommended a few study design strategies to minimize vehicle response observed in DED trials. This review briefly describes the factors that lead to placebo/vehicle response in DED trials and focuses on the aspects of clinical trial design that can be improved to mitigate vehicle response. In addition, it presents the observations from a recent ECF843 phase 2b study, wherein the study design approach consisted of a vehicle run-in phase, withdrawal phase, and masked treatment transition, and led to consistent data for DED signs and symptoms and reduced vehicle response post randomization.

Innovative Technologies in CNS Trials: Promises and Pitfalls for Recruitment, Retention, and Representativeness

Objective

Recruitment of a sufficiently large and representative patient sample and its retention during central nervous system (CNS) trials presents major challenges for study sponsors. Technological advances are reshaping clinical trial operations to meet these challenges, and the COVID-19 pandemic further accelerated this development.

Method of Research

The International Society for CNS Clinical Trials and Methodology (ISCTM; www.isctm.org) Innovative Technologies for CNS Trials Working Group surveyed the state of technological innovations for improved recruitment and retention and assessed their promises and pitfalls.

Results

Online advertisement and electronic patient registries can enhance recruitment, but challenges with sample representativeness, conversion rates from eligible prescreening to enrolled patients, data privacy and security, and patient identification remain hurdles for optimal use of these technologies. Electronic medical records (EMR) mining with artificial intelligence (AI)/machine learning (ML) methods is promising but awaits translation into trials. During the study treatment phase, technological innovations increasingly support participant retention, including adherence with the investigational treatment. Digital tools for adherence and retention support take many forms, including patient-centric communication channels between researchers and participants, real-time study reminders, and digital behavioral interventions to increase study compliance. However, such tools add technical complexities to trials, and their impact on the generalizability of results are largely unknown.

Conclusion

Overall, the group found a scarcity of systematic data directly assessing the impact of technological innovations on study recruitment and retention in CNS trials, even for strategies with already high adoption, such as online recruitment. Given the added complexity and costs associated with most technological innovations, such data is needed to fully harness technologies for CNS trials and drive further adoption.

Empirical progression criteria thresholds for feasibility outcomes in HIV clinical trials: a methodological study

INTRODUCTION

Pilot and feasibility trials use predetermined thresholds for feasibility outcomes to decide if a larger trial is feasible. These thresholds may be derived from the literature, observational data, or clinical experience. The aim of this study was to determine empirical estimates for feasibility outcomes to inform future HIV pilot randomized trials.

METHODS

We conducted a methodological study of HIV clinical trials indexed in the past 5 years (2017-2021) in the PubMed database. We included trials of people living with HIV individually randomized to any type of intervention and excluded pilot trials and cluster randomized trials. Screening and data extraction were conducted in duplicate. We computed estimates for recruitment, randomization, non-compliance, lost to follow-up, discontinuation, and the proportion analyzed using a random effects meta-analysis of proportions and reported these estimates according to the following subgroups: use of medication, intervention type, trial design, income level, WHO region, participant type, comorbidities, and source of funding. We report estimates with 95% confidence intervals.

RESULTS

We identified 2122 studies in our search, of which 701 full texts were deemed relevant, but only 394 met our inclusion criteria. We found the following estimates: recruitment (64.1%; 95% CI 57.7 to 70.3; 156 trials); randomization (97.1%; 95% CI 95.8 to 98.3; 187 trials); non-compliance (3.8%; 95% CI 2.8 to 4.9; 216 trials); lost to follow-up (5.8%; 95% CI 4.9 to 6.8; 251 trials); discontinuation (6.5%; 95% CI 5.5 to 7.5; 215 trials); analyzed (94.2%; 95% CI 92.9 to 95.3; 367 trials). There were differences in estimates across most subgroups.

CONCLUSION

These estimates may be used to inform the design of HIV pilot randomized trials with careful consideration of variations due to some of the subgroups investigated.

CONSORT Harms 2022 statement, explanation, and elaboration: updated guideline for the reporting of harms in randomized trials

Randomized controlled trials remain the reference standard for healthcare research on effects of interventions, and the need to report both benefits and harms is essential. The Consolidated Standards of Reporting Trials (the main CONSORT) statement includes one item on reporting harms (i.e., all important harms or unintended effects in each group). In 2004, the CONSORT group developed the CONSORT Harms extension; however, it has not been consistently applied and needs to be updated. Here, we describe CONSORT Harms 2022, which replaces the CONSORT Harms 2004 checklist, and shows how CONSORT Harms 2022 items could be incorporated into the main CONSORT checklist. Thirteen items from the main CONSORT were modified to improve harms reporting. Three new items were added. In this article, we describe CONSORT Harms 2022 and how it was integrated into the main CONSORT checklist and elaborate on each item relevant to complete reporting of harms in randomized controlled trials. Until future work from the CONSORT group produces an updated checklist, authors, journal reviewers, and editors of randomized controlled trials should use the integrated checklist presented in this paper.

A scoping review identifies multiple comments suggesting modifications to SPIRIT 2013 and CONSORT 2010

OBJECTIVES

To identify, summarize, and analyse comments on the core reporting guidelines for protocols of randomized trials (Standard Protocol Items: Recommendations for Interventional Trials [SPIRIT] 2013) and for completed trials (Consolidated Standards of Reporting Trials [CONSORT] 2010), with special emphasis on suggestions for guideline modifications.

METHODS

We included documents written in English and published after 2010 that explicitly commented on SPIRIT 2013 or CONSORT 2010. We searched four bibliographic databases (Embase and MEDLINE to June 2022; Web of Science and Google Scholar to April 2022) and other sources (e.g., the EQUATOR Network website, the BMC Blog Network, and the BMJ rapid response section). Two authors independently assessed documents for eligibility and extracted data on basic characteristics and the wording of the main comments. We categorized comments as 'suggestion for modification to the wording of an existing guideline item,' 'suggestion for a new item,' or 'reflections on challenges or strengths.' We provided a summary and examples of the proposed suggestions and categorized comments into those that were directly linked to empirical investigations, were continuations of previous methodological discussions, or reflected new methodological developments.

RESULTS

We assessed full text of 2,320 potentially eligible documents and included 93 documents with 114 comments. In total, 37 comments suggested modifications to existing guideline items. The participant flow section of CONSORT 2010 received the most comments (eight comments made different suggestions, e.g., one comment suggested to add numbers on nonrandomized screened participants). There were 46 comments suggesting new items. Multiple suggestions were related to trial interventions (eight comments made different suggestions, e.g., one comment suggested to add content on cointerventions), blinding (six comments suggested to add content on risk of unblinding), statistical methods (five comments made different suggestions, e.g., one comment suggested to add content on blinding of statisticians), and participant flow (seven comments made different suggestions, e.g., three comments suggested to add content on missing data). Half (53%) of the suggestions were directly linked to empirical investigations. Six (7%) suggestions were continuations of previous methodological discussions and five (6%) suggestions reflected new methodological developments related to conflicts of interest and funding, data sharing, and patient and public involvement.

CONCLUSION

The issues raised provide context to authors, peer reviewers, editors, and readers of trials using SPIRIT 2013 and CONSORT 2010 and inform the planned updates of the core guidelines.

Investigating the trends in patient-reported outcomes pre-treatment and implications to efficacy analyses: A post-hoc analysis of a cancer clinical trial

Background

Uncertainty around key elements of an appropriate patient-reported outcome (PRO) baseline assessment introduces trial-specific variation in oncology clinical trials with a poorly understood consequence on drug evaluation decisions. This research investigated the impact of multiple pre-treatment PRO assessments and timing of assessments in a clinical trial.

Methods

A post-hoc analysis of a completed phase 3, open-label, randomized, parallel arm clinical trial in non-small cell lung cancer with two pre-treatment PRO assessments (screening and Week 1 Day 1 [W1D1]). Descriptive analyses, mixed models for repeated measures and time until definitive deterioration analyses were performed to estimate differences between treatment arms. Through model adjustments, different baseline specifications and assessment timing (pre/post-randomization) on W1D1 PROs were evaluated.

Results

Patients with both pre-treatment PRO assessments were included in the analysis (N = 535). Numerically small average change scores were observed between screening and W1D1 (mean change, 0-100 scale ranges): Chest pain (-0.94), Cough (-0.94), Dyspnea (1.27), Physical functioning (-1.19). Both pre-treatment assessments were moderately-highly correlated (r: 0.55-0.78) and no trend was found for deterioration or improvement during this period. Varying baseline definitions in the models produced slight differences in model fit but no impact on the between treatment group effect estimate. W1D1 PRO scores were not statistically influenced by assessment timing pre/post-randomization (p-values: 0.142-0.628).

Conclusion

Findings from this study question the need for multiple pre-treatment PRO assessments in oncology drug development trials and the degree of bias thought to be introduced through patient knowledge of treatment assignment. Implications for researchers are presented.

A SuperLearner Approach to Predict Run-In Selection in Clinical Trials

A critical early step in a clinical trial is defining the study sample that appropriately represents the target population from which the sample will be drawn. Envisaging a “run-in” process in study design may accomplish this task; however, the traditional run-in requires additional patients, increasing times, and costs. The possible use of the available a-priori data could skip the run-in period. In this regard, ML (machine learning) techniques, which have recently shown considerable promising usage in clinical research, can be used to construct individual predictions of therapy response probability conditional on patient characteristics. An ensemble model of ML techniques was trained and validated on twin randomized clinical trials to mimic a run-in process within this framework. An ensemble ML model composed of 26 algorithms was trained on the twin clinical trials. SuperLearner (SL) performance for the Verum (Treatment) arm is above 70% sensitivity. The Positive Predictive Value (PPP) achieves a value of 80%. Results show good performance in the direction of being useful in the simulation of the run-in period; the trials conducted in similar settings can train an optimal patient selection algorithm minimizing the run-in time and costs of conduction.

Considerations for Amyotrophic Lateral Sclerosis (ALS) Clinical Trial Design

Thoughtful clinical trial design is critical for efficient therapeutic development, particularly in the field of amyotrophic lateral sclerosis (ALS), where trials often aim to detect modest treatment effects among a population with heterogeneous disease progression. Appropriate outcome measure selection is necessary for trials to provide decisive and informative results. Investigators must consider the outcome measure's reliability, responsiveness to detect change when change has actually occurred, clinical relevance, and psychometric performance. ALS clinical trials can also be performed more efficiently by utilizing statistical enrichment techniques. Innovations in ALS prediction models allow for selection of participants with less heterogeneity in disease progression rates without requiring a lead-in period, or participants can be stratified according to predicted progression. Statistical enrichment can reduce the needed sample size and improve study power, but investigators must find a balance between optimizing statistical efficiency and retaining generalizability of study findings to the broader ALS population. Additional progress is still needed for biomarker development and validation to confirm target engagement in ALS treatment trials. Selection of an appropriate biofluid biomarker depends on the treatment mechanism of interest, and biomarker studies should be incorporated into early phase trials. Inclusion of patients with ALS as advisors and advocates can strengthen clinical trial design and study retention, but more engagement efforts are needed to improve diversity and equity in ALS research studies. Another challenge for ALS therapeutic development is identifying ways to respect patient autonomy and improve access to experimental treatment, something that is strongly desired by many patients with ALS and ALS advocacy organizations. Expanded access programs that run concurrently to well-designed and adequately powered randomized controlled trials may provide an opportunity to broaden access to promising therapeutics without compromising scientific integrity or rushing regulatory approval of therapies without adequate proof of efficacy.

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.

The value of adherence information during clinical pharmaceutical trials

BACKGROUND/AIMS

The quality of the evidence used to evaluate a drug's safety and efficacy depends, in part, on how well participants adhere to the prescribed drug-taking regime. There are multiple approaches to measure adherence in clinical trials, varying in their cost and accuracy. We demonstrate a method for evaluating the cost-effectiveness of common adherence monitoring methods, considering the costs and data quality for drugs that differ in how forgiving they are of nonadherence.

METHODS

We propose a simulation approach to estimate the value of evidence about adherence, considering both costs of collection and potential errors in interpreting clinical trial results. We demonstrate the approach with a simulated clinical trial of nitrendipine, a common calcium channel blocker. We consider two trial designs, one using pretrial adherence to "enrich" the trial sample and one without an enrichment strategy. We use scenarios combining high and low values of two key properties of a clinical trial: participant adherence and drug forgiveness.

RESULTS

Under the conditions of these simulations, the most cost-effective adherence monitoring approach depends on both trial participant adherence and drug forgiveness. For example, the enrichment strategy is not cost-effective for the base scenario (high forgiveness and high adherence), but is for other scenarios. We also estimate the effects of evaluable patient analysis, a controversial procedure that excludes nonadherent participants from the analyses, after a trial is completed.

CONCLUSIONS

Our proposed approach can guide drug regulators and developers in designing efficient clinical trials and assessing the impact of nonadherence on trial results. It can identify cost-effective adherence-monitoring methods, given available knowledge about the methods, drug, and patients' expected adherence.

Review of disease-modifying drug trials in amyotrophic lateral sclerosis

We analysed clinical trials of pharmacological interventions on patients with amyotrophic lateral sclerosis (ALS), and compared study quality and design features. The systematic review included articles published in PubMed and trials registered in ClinicalTrials.gov. Included studies were randomised double-blind placebo-controlled clinical trials assessing a disease-modifying pharmacological intervention. Studies were excluded if primary end points were safety or dose finding. A total of 28 735 articles and 721 current trials were identified. 76 published articles and 23 ongoing trials met inclusion criteria; they referred to distinct populations comprising 22 817 participants with ALS. Most articles and all current trials had parallel group design; few articles had cross-over design. A run-in observation period was included in about 20% of published studies and ongoing trials. Primary end points included functional assessment, survival, muscle strength, respiratory function, biomarkers and composite measures. Most recent trials had only functional assessment and survival. Risk of bias was high in 23 articles, moderate in 35, low in 18. A disease modification effect was observed for 10 interventions in phase II studies, two of which were confirmed in phase III. Three confirmatory phase III studies are currently underway. The present review provides cues for the design of future trials. Functional decline and survival, as single or composite measures, stand as the reference end points. Post hoc analyses should not be performed, particularly in studies using composite end points. There is a general agreement on diagnostic criteria; but eligibility criteria must be improved. Run-in observations may be used for censoring patients but are discouraged for refining participants' eligibility. The ALS Functional Rating Scale-Revised needs improvement for use as an ordinal measure of functional decline.

Association of Single-blind Placebo Run-in Periods With the Placebo Response in Randomized Clinical Trials of Antidepressants: A Systematic Review and Meta-analysis

Importance

Single-blind placebo run-in (PRI) periods are common in randomized clinical trials (RCTs) of treatment for depression. They aim to increase sensitivity to detect drug effects; however, the association of PRI periods with study outcomes remains unclear. This is concerning given the costs of PRI periods to patients and investigators.

Objective

To examine the association of the use of PRI periods with the placebo response, drug response, and drug-placebo difference among RCTs of antidepressants.

Data Sources

MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and PsycINFO, as well as repositories of unpublished studies, were systematically searched up to July 2021.

Study Selection

Included studies were double-blind, placebo-controlled RCTs of antidepressant medication among adults with depressive disorders.

Data Extraction and Synthesis

Data were extracted into a coding sheet, including the characteristics of studies, the characteristics of PRI periods, and the outcomes of studies.

Main Outcomes and Measures

Study outcomes were the primary depression symptom measure reported by the RCT. These outcomes were used to calculate effect sizes (Hedges g) of the within-group drug response and placebo response as well as the drug-placebo difference. Random-effects meta-analysis was used to calculate effect sizes, and subgroup analyses were used to compare outcomes depending on use of PRI periods.

Results

A total of 347 trials (representing 89 183 participants) were included; 174 studies (50%) reported using a single-blind PRI period. Response outcome data were available for 189 studies. Studies using PRI periods reported a smaller placebo response (g = 1.05 [95% CI, 0.98-1.11]; I2 = 82%) than studies that did not use a PRI period (g = 1.15 [95% CI, 1.09-1.21]; I2 = 81%; P = .02). Subgroup analysis showed a larger drug response size among studies that did not use a PRI period (g = 1.55 [95% CI, 1.49-1.61]; I2 = 85%) than those that did use a PRI period (g = 1.42 [95% CI, 1.36-1.48]; I2 = 81%; P = .001). The drug-placebo difference did not differ by use of PRI periods (g = 0.33 [95% CI, 0.29-0.38]; I2 = 47% for use of a PRI period vs g = 0.34 [95% CI, 0.30-0.38]; I2 = 54% for no use of PRI periods; P = .92). The likelihood of response to drug vs placebo also did not differ between studies that used a PRI period (odds ratio, 1.89 [95% CI, 1.76-2.03]) and those that did not use a PRI period (odds ratio, 1.77 [95% CI, 1.65-1.89]; P = .18).

Conclusions and Relevance

This study suggests that RCTs using PRI periods yield smaller within-group changes across both placebo and drug groups compared with RCTs without PRI periods. The reduction in effect size across groups was equivalent in magnitude. Consequently, PRI studies do not observe larger drug-placebo differences, suggesting that they do not increase trial sensitivity. As such, given the resources and probable deception required and risk to external validity, the practice of using PRI periods in RCTs of antidepressants should be ended.

Facilitator Contact, Discussion Boards, and Virtual Badges as Adherence Enhancements to a Web-Based, Self-guided, Positive Psychological Intervention for Depression: Randomized Controlled Trial

Background

Adherence to self-guided interventions tends to be very low, especially in people with depression. Prior studies have demonstrated that enhancements may increase adherence, but little is known about the efficacy of various enhancements in comparison to, or in combination with, one another.

Objective

The aim of our study is to test whether 3 enhancements—facilitator contact (FC), an online discussion board, and virtual badges (VB)—alone, or in combination, improve adherence to a self-guided, web-based intervention for depression. We also examined whether age, gender, race, ethnicity, comfort with technology, or baseline depression predicted adherence or moderated the effects that each enhancement had on adherence.

Methods

Participants were recruited through web-based sources and, after completing at least 4 out of 7 daily emotion reports, were sequentially assigned to 1 of 9 conditions—the intervention alone; the intervention plus 1, 2, or all 3 enhancements; or an emotion reporting control condition. The intervention was a positive psychological program consisting of 8 skills that specifically targeted positive emotions, and it was delivered over 5 weeks in a self-guided, web-based format. We operationalized adherence as the number of skills accessed.

Results

A total of 602 participants were enrolled in this study. Participants accessed, on average, 5.61 (SD 2.76) of 8 skills. The total number of enhancements participants received (0-3) did not predict the number of skills accessed. Participants who were assigned to the VB+FC condition accessed significantly more skills than those in the intervention only conditions. Furthermore, participants in arms that received the combination of both the VB and FC enhancements (VB+FC and VB+FC+online discussion board) accessed a greater number of skills relative to the number of skills accessed by participants who received either VB or FC without the other. Moderation analyses revealed that the receipt of VB (vs no VB) predicted higher adherence among participants with moderately severe depression at baseline.

Conclusions

The results suggested that the VB+FC combination significantly increased the number of skills accessed in a self-guided, web-based intervention for elevated depression. We have provided suggestions for refinements to these enhancements, which may further improve adherence.

Trial Registration

ClinicalTrials.gov NCT02861755; http://clinicaltrials.gov/ct2/show/NCT02861755

Importance of Internal Variability in Clinical Trials of Cardiovascular Disease

A well conducted randomised controlled trial (RCT) is extremely important in the field of cardiovascular medicine. At the same time, it is equally important to understand the strengths and limitations of any RCT, and internal variability is a concept in clinical trials that is poorly understood. Variability in a clinical trial may be introduced at an individual level or during measurement, sampling, or conduct of the trial. It is not the same as internal validity, which is a broader concept of accuracy; to be valid, a study should minimise variability and have sound methodology. There are various steps that may be followed to minimise the internal variability in a clinical trial. One aspect of great importance is the adjudication process, which should be done meticulously and is often a step that is overlooked. It is important to standardise each step as much as possible, to ensure consistency and reduce noise at all levels. The concepts discussed in this review may serve as a roadmap to limit the influence of internal variability and maximise internal validity of RCT results.

Three week compared to seven week run-in period length and the assessment of pre-randomization adherence: A study within a trial

BACKGROUND/AIMS

To examine how measuring adherence at 3 weeks by self-report and pill counts compares to measurements at 7 weeks in a pre-randomization run-in period.

METHODS

Study within a trial of an international parallel group randomized controlled trial (RCT) that compares spironolactone to placebo. Adults receiving dialysis enter an 8-week active run-in period with spironolactone. Adherence was assessed by both self-report and pill counts in a subgroup of participants at both 3 weeks and 7 weeks.

RESULTS

332 participants entered the run-in period of which 166 had complete data. By self-report, 146/166 (94.0%) and 153/166 (92.2%) had at least 80% adherence at 3 and 7 weeks respectively (kappa = 0.27 (95% C.I. 0.16 to 0.38). By pill counts, the mean (SD) adherence was 96.5% (16.1%) and 92.4% (18.2%) at 3 and 7 weeks respectively (r = 0.32) with a mean (SD) difference of 3.1% (17.8%) and a 95% limit of agreement from -31.7% to +37.9%. The proportion of adherent participants by self-report and pill counts at 3 weeks agreed in 87.4% of participants (McNemar's p-value 0.58, kappa 0.11, p = 0.02) and at 7 weeks agreed in 92.2% (McNemar's p-value 0.82, kappa 0.47, p < 0.001).

CONCLUSIONS

Three and seven-week run-in periods and both self-reported and pill count assessments performed similarly.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03020303.

The placebo response rate in pharmacological trials in patients with irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Clinical trials in irritable bowel syndrome are associated with high placebo response rates. We aimed to identify the magnitude of the placebo response and the contributing factors to this occurrence.

METHODS

We did a systematic review and meta-analysis with a search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials between April 1, 1959, and April 30, 2020. We included all randomised controlled trials that compared an active pharmacotherapeutic agent with placebo and had a dichotomous outcome of response to therapy (in terms of global improvement or improvement in abdominal pain) in adults (aged ≥18 years) with irritable bowel syndrome. Exclusion criteria were trials reporting on treatment satisfaction as a dichotomous outcome of response to therapy or clinician-reported outcomes and a treatment duration of less than 4 weeks. Our main outcome was identification of the magnitude of the pooled placebo response rate for the following endpoints: global improvement, abdominal pain, and US Food and Drug Administration (FDA) endpoints. We extracted information from published reports and pooled proportions through meta-analysis with random effects. The study was registered with PROSPERO, CRD42020170908.

FINDINGS

Of the 6863 publications identified, 70 articles describing 73 randomised controlled trials were included in our analysis. The pooled placebo response rate was 27·3% (95% CI 24·3-30·9) using the global improvement endpoint, 34·4% (31·2-37·8) using the abdominal pain endpoint, and 17·9% (15·2-21·0) using the composite FDA endpoint responder definition, all with substantial heterogeneity between the trials. Studies published before 2006, and those done in Europe, with a parallel design, a run-in period of 2 weeks or less, a dose schedule of three times a day or more, or a smaller sample size of the control group were significantly associated with an increased pooled placebo response rate.

INTERPRETATION

More than a quarter of patients with irritable bowel syndrome had a placebo response in terms of global improvement, with multiple associated moderators. We recommend future trials apply a run-in period of at least 2 weeks and dose once or twice a day to minimise the placebo response rate.

FUNDING

None.

Pharmacological treatment trials of agitation in Alzheimer's disease: A systematic review of ClinicalTrials.gov registered trials

INTRODUCTION

There is increasing emphasis on the importance of optimizing and standardizing clinical trials of agitation in Alzheimer's disease (AD), but the risks of bias arising from published trials and the number and design of unpublished studies are poorly understood.

METHODS

Using the ClinicalTrials.gov database, we systematically reviewed all registered investigational clinical trials for agitation in AD to describe the landscape of agitation drug treatment trials and to assess their quality and generalizability.

RESULTS

We included 52 clinical studies registered over the past 25 years. Within published randomized controlled trials (RCTs), there was a high rate of participant dropout, poor reporting of randomization procedures, and inconsistent definitions of the sample included for analysis. There was also evidence of publication and funder bias.

DISCUSSION

We discuss factors that limit the internal and external validity of published RCTs and make additional recommendations for the conduct and reporting of future clinical trials of agitation in AD.

Where to Next for Optimizing Adherence in Large-Scale Trials of Continuous Positive Airway Pressure?

Large-scale randomized trials of positive airway pressure (PAP) efficacy have been largely negative but PAP adherence was notably suboptimal across the trials. To address this limitation, evidence-based PAP adherence protocols embedded within the larger trial protocol are recommended. The complexity of such protocols depends on adequacy of resources, including funding and inclusion of behavioral scientist experts on the scientific team, and trial-specific considerations (eg, target population) and methods. Recommendations for optimizing PAP adherence in large-scale trials are set forth that address rigor and reproducibility.

Efficacy and Safety of Pregabalin for Fibromyalgia in a Population of Chinese Subjects

PURPOSE

Fibromyalgia (FM) may go underdiagnosed and untreated in China in part due to a lack of awareness and understanding of the condition, and limited available treatments.

PATIENTS AND METHODS

This randomized, double-blind, Phase III local registration trial compared the efficacy and safety of pregabalin (flexibly dosed 300-450 mg/day) versus placebo for the management of pain in Chinese adults diagnosed with FM according to American College of Rheumatology 1990 criteria, across 22 centers within China. Patients reported pain score of ≥40 mm on 100-mm scale (from 0 "no pain" to 100 "worst possible pain"). The primary efficacy endpoint was change from baseline to Week 14 in mean pain score (MPS). Secondary endpoints included measures of sleep and sleep interference. Safety and tolerability were monitored throughout.

RESULTS

Median pregabalin dose was 335 mg/day. A significant reduction from baseline to Week 14 in weekly MPS was seen for patients treated with pregabalin (n=170) versus placebo (n=164) (least-squares mean difference [95% confidence interval]: -0.73 [-1.10 to -0.36]; P=0.0001). Significantly greater proportions of patients experienced ≥30% and ≥50% reductions in MPS at Week 14 with pregabalin versus placebo. Pregabalin-treated subjects demonstrated improvements in measures of sleep and sleep interference. Pregabalin was generally well tolerated. The most common adverse events were dizziness and somnolence; no serious adverse events (SAEs) occurred in pregabalin-treated subjects. Nine placebo-treated subjects experienced SAEs.

CONCLUSION

Pregabalin (300-450 mg/day) is a safe and effective treatment for reducing pain and improving sleep in native Chinese subjects with FM.

CLINICALTRIALSGOV IDENTIFIER

NCT01387607.

New approaches to symptomatic treatments for Alzheimer's disease

BACKGROUND

Successful development of agents that improve cognition and behavior in Alzheimer's disease (AD) is critical to improving the lives of patients manifesting the symptoms of this progressive disorder.

DISCUSSION

There have been no recent approvals of cognitive enhancing agents for AD. There are currently 6 cognitive enhancers in Phase 2 trials and 4 in phase 3. They represent a variety of novel mechanisms. There has been progress in developing new treatments for neuropsychiatric symptoms in AD with advances in treatment of insomnia, psychosis, apathy, and agitation in AD. There are currently 4 AD-related psychotropic agents in Phase 2 trials and 7 in Phase 3 trials. Many novel mechanisms are being explored for the treatment of cognitive and behavioral targets. Progress in trial designs, outcomes measures, and population definitions are improving trial conduct for symptomatic treatment of AD.

CONCLUSIONS

Advances in developing new agents for cognitive and behavioral symptoms of AD combined with enhanced trial methods promise to address the unmet needs of patients with AD for improved cognition and amelioration of neuropsychiatric symptoms.

Precision clinical trials: a framework for getting to precision medicine for neurobehavioural disorders

The goal of precision medicine (individually tailored treatments) is not being achieved for neurobehavioural conditions such as psychiatric disorders. Traditional randomized clinical trial methods are insufficient for advancing precision medicine because of the dynamic complexity of these conditions. We present a pragmatic solution: the precision clinical trial framework, encompassing methods for individually tailored treatments. This framework includes the following: (1) treatment-targeted enrichment, which involves measuring patients' response after a brief bout of an intervention, and then randomizing patients to a full course of treatment, using the acute response to predict long-term outcomes; (2) adaptive treatments, which involve adjusting treatment parameters during the trial to individually optimize the treatment; and (3) precise measurement, which involves measuring predictor and outcome variables with high accuracy and reliability using techniques such as ecological momentary assessment. This review summarizes precision clinical trials and provides a research agenda, including new biomarkers such as precision neuroimaging, transcranial magnetic stimulation-electroencephalogram digital phenotyping and advances in statistical and machine-learning models. Validation of these approaches - and then widespread incorporation of the precision clinical trial framework - could help achieve the vision of precision medicine for neurobehavioural conditions.

Prerandomization run-in periods in randomized controlled trials of chronic diseases: a methodological study

OBJECTIVE

To systematically review the epidemiology of prerandomized run-in periods in randomized controlled trials (RCTs) of chronic diseases.

STUDY DESIGN AND SETTING

Meta-epidemiologic study of all RCTs from the four highest impact medical journals from 2011 to 2016. Eligible trials included parallel RCTs that evaluated pharmacologic therapies in adults with chronic diseases with a minimum follow-up of 24 weeks.

RESULTS

Of 262 eligible manuscripts, 48 (18.3%), representing 42 unique RCTs, included run-in periods. Run-in periods were most common in cardiovascular disease and diabetes trials. Of the 42 RCTs, in 22 patients received the experimental therapy, 15 placebo, 4 both (either sequentially or in combination), and one did not report the run-in period drug. The median run-in period duration was 28 days (Q1: Q3 14: 66 days). Reasons for including a run-in period included ensuring eligibility criteria were met (18, 42.9%), excluding participants with nonadherence (18, 42.9%) and intolerances to therapy (15, 35.7%), and to standardize therapy prior to randomization (8, 19.0%). The median run-in completion rate was 77.4% (Q1: Q3 62.2:87.8%).

CONCLUSIONS

Run-in periods are uncommon in RCTs of chronic drug treatments and when used, their reporting is heterogeneous. Further research to improve the design, use, and reporting of run-in periods is necessary.

Improving rheumatoid arthritis comparative effectiveness research through causal inference principles: systematic review using a target trial emulation framework

OBJECTIVES

Target trial emulation is an intuitive design framework that encourages investigators to formulate their comparative effectiveness research (CER) question as a hypothetical randomised controlled trial (RCT). Our aim was to systematically review CER studies in rheumatoid arthritis (RA) to provide examples of design limitations that could be avoided using target trial emulation, and how these limitations might introduce bias.

METHODS

We searched for head-to-head CER studies of biologic disease modifying anti-rheumatic drugs (DMARDs) in RA. Study designs were reviewed for seven components of the target trial emulation framework: eligibility criteria, treatment strategies, assignment procedures, follow-up period, outcome, causal contrasts of interest (ie, intention-to-treat (ITT) or per-protocol effect) and analysis plan. Hypothetical trials corresponding to the reported methods were assessed to identify design limitations that would have been avoided with an explicit target trial protocol. Analysis of the primary effectiveness outcome was chosen where multiple analyses were performed.

RESULTS

We found 31 CER studies, of which 29 (94%) had at least one design limitation belonging to seven components. The most common limitations related to: (1) eligibility criteria: 19/31 (61%) studies used post-baseline information to define baseline eligibility; (2) causal contrasts: 25 (81%) did not define whether ITT or per-protocol effects were estimated and (3) assignment procedures: 13 (42%) studies did not account for confounding by indication or relied solely on statistical confounder selection.

CONCLUSIONS

Design limitations were found in 94% of observational CER studies in RA. Target trial emulation is a structured approach for designing observational CER studies that helps to avoid potential sources of bias.

Triple therapy for COPD: a crude analysis from a systematic review of the evidence

We systematically reviewed the current knowledge on fixed-dose triple therapies for the treatment of chronic obstructive pulmonary disease (COPD), with a specific focus on its efficacy versus single bronchodilation, double fixed dose combinations, and open triple therapies. Articles were retrieved from PubMed, Embase, and Scopus up to 3 August 2018. We selected articles with randomized controlled or crossover design conducted in patients with COPD and published as full-length articles or scientific letters, evaluating triple therapy combinations in a single or different inhaler, and with efficacy data versus monocomponents, double combinations, or open triple therapies. Our systematic search reported 108 articles, of which 24 trials were finally selected for the analysis. A total of 7 studies with fixed dose triple therapy combinations, and 17 studies with open triple therapies combinations. Triple therapy showed improvements in lung function [trough forced expiratory volume (FEV₁₎ ranging from not significant (NS) to 147 ml], health status using the St. George’s Respiratory Questionnaire [(SGRQ) from NS to 8.8 points], and exacerbations [risk ratio (RR) from NS to 0.59 for all exacerbations] versus single or double therapies with a variability in the response, depending the specific combination, and the comparison group. The proportion of adverse effects was similar between study groups, the exception being the increase in pneumonia for some inhaled corticosteroid (ICS) containing groups.

The reviews of this paper are available via the supplementary material section.

The clinical implications of triple therapy in fixed-dose combination in COPD: from the trial to the patient

The emergence of a fixed-dose combination (FDC) of a long-acting ß₂-agonist (LABA), a long-acting muscarinic antagonist (LAMA), and an inhaled corticosteroid (ICS) in a single inhalation device has changed the approach to inhaled therapy. Although clinical trials describe the efficacy and safety of these FDCs, their use in daily clinical practice can present challenges for the clinician in two specific scenarios. In patients who are already receiving triple therapy via different devices, switching to FDCs could confer benefits by reducing critical errors in the management of inhalers, improving therapeutic adherence, and lowering costs, while maintaining the same clinical efficacy. In patients who are not receiving triple therapy in different devices and who require a change in treatment, triple therapy FDC has shown benefits in clinical trials. Although methodological differences among the trials advise against direct comparison, clinical results show good efficacy, but also considerable variability, and a number of clinical outcomes have yet to be explored. In the future, trials must be developed to complete clinical efficacy data. Real-world efficacy trials are needed, and studies must be designed to determine the profile of patients who present a greater therapeutic response to each FDC in order to pave the way towards more personalized treatment.

Indicators of retention in remote digital health studies: a cross-study evaluation of 100,000 participants

Digital technologies such as smartphones are transforming the way scientists conduct biomedical research. Several remotely conducted studies have recruited thousands of participants over a span of a few months allowing researchers to collect real-world data at scale and at a fraction of the cost of traditional research. Unfortunately, remote studies have been hampered by substantial participant attrition, calling into question the representativeness of the collected data including generalizability of outcomes. We report the findings regarding recruitment and retention from eight remote digital health studies conducted between 2014-2019 that provided individual-level study-app usage data from more than 100,000 participants completing nearly 3.5 million remote health evaluations over cumulative participation of 850,000 days. Median participant retention across eight studies varied widely from 2-26 days (median across all studies = 5.5 days). Survival analysis revealed several factors significantly associated with increase in participant retention time, including (i) referral by a clinician to the study (increase of 40 days in median retention time); (ii) compensation for participation (increase of 22 days, 1 study); (iii) having the clinical condition of interest in the study (increase of 7 days compared with controls); and (iv) older age (increase of 4 days). Additionally, four distinct patterns of daily app usage behavior were identified by unsupervised clustering, which were also associated with participant demographics. Most studies were not able to recruit a sample that was representative of the race/ethnicity or geographical diversity of the US. Together these findings can help inform recruitment and retention strategies to enable equitable participation of populations in future digital health research.

The Clinical Implications of Triple Therapy in Fixed-Dose Combination in COPD: From the Trial to the Patient

The emergence of a fixed-dose combination (FDC) of a long-acting β₂-agonists (LABAS), a long-acting anticholinergic agent (LAMA), and an inhaled corticosteroid (ICS) in a single inhalation device has changed the approach to inhaled therapy. Although clinical trials describe the efficacy and safety of these FDCs, their use in daily clinical practice can present challenges for the clinician in two specific scenarios. In patients who are already receiving triple therapy via different devices, switching to FDCs could confer benefits by reducing critical errors in the management of inhalers, improving therapeutic adherence, and lowering costs, while maintaining the same clinical efficacy. In patients who are not receiving triple therapy in different devices and who require a change in treatment, triple therapy FDC has shown benefits in clinical trials. Although methodological differences among the trials advise against direct comparison, clinical results show good efficacy, but also considerable variability, and a number of clinical outcomes have yet to be explored. In the future, trials must be developed to complete clinical efficacy data. Real-world efficacy trials are needed, and studies must be designed to determine the profile of patients who present a greater therapeutic response to each FDC in order to pave to way towards more personalized treatment.

TRC-PAD: Accelerating Recruitment of AD Clinical Trials through Innovative Information Technology

BACKGROUND

The Trial-Ready Cohort for Preclinical/Prodromal Alzheimer's Disease (TRC-PAD) Informatics Platform (TRC-PAD IP) was developed to facilitate the efficient selection, recruitment, and assessment of study participants in support of the TRC-PAD program.

OBJECTIVES

Describe the innovative architecture, workflows, and components of the TRC-PAD IP.

DESIGN

The TRC-PAD IP was conceived as a secure, scalable, multi-tiered information management platform designed to facilitate high-throughput, cost-effective selection, recruitment, and assessment of TRC-PAD study participants and to develop a learning algorithm to select amyloid-bearing participants to participate in trials of early-stage Alzheimer's disease.

SETTING

TRC-PAD participants were evaluated using both web-based and in-person assessments to predict their risk of amyloid biomarker abnormalities and eligibility for preclinical and prodromal clinical trials. Participant data were integrated across multiple stages to inform the prediction of amyloid biomarker elevation.

PARTICIPANTS

TRC-PAD participants were age 50 and above, with an interest in participating in Alzheimer's research.

MEASUREMENTS

TRC-PAD participants' cognitive performance and subjective memory concerns were remotely assessed on a longitudinal basis to predict participant risk of biomarker abnormalities. Those participants determined to be at the highest risk were invited to an in-clinic screening visit for a full battery of clinical and cognitive assessments and amyloid biomarker confirmation using positron emission tomography (PET) or lumbar puncture (LP).

RESULTS

The TRC-PAD IP supported growth in recruitment, screening, and enrollment of TRC-PAD participants by leveraging a secure, scalable, cost-effective cloud-based information technology architecture.

CONCLUSIONS

The TRC-PAD program and its underlying information management infrastructure, TRC-PAD IP, have demonstrated feasibility concerning the program aims. The flexible and modular design of the TRC-PAD IP will accommodate the introduction of emerging diagnostic technologies.