A systematic survey of adaptive trials shows substantial improvement in methods is needed

OBJECTIVES

To investigate the design, conduct, and analysis of adaptive trials through a systematic survey and provide recommendations for future adaptive trials.

STUDY DESIGN AND SETTING

We systematically searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases up to January 2020. We included trials that were self-described as adaptive trials or applied adaptive designs. We identified three frequently used adaptive designs and summarized their methodological details in terms of design, conduct, and analysis. Lastly, we provided recommendations for future adaptive trials.

RESULTS

We included a total of 128 trials in this study. The primary motivations for using adaptive design were to speed up the trials and facilitate decision-making (n = 29, 31.5%). The three most frequently used methods were group sequential design (GSD) (n = 71, 55.5%), adaptive dose-finding design (ADFD) (n = 35, 27.3%), and adaptive randomization design (ARD) (n = 26, 20.3%). The timing and frequency of interim analysis were detailed in three-fourths of the GSD trials (n = 55, 77.5%) and in half of the ADFD trials (n = 19, 54.3%); however, more than half of the ARD trials (n = 15, 57.7%) did not provide this information. Some trials selected a different outcome than the primary outcome for interim analysis (GSD: n = 7, 12.7%; ADFD: n = 8, 27.6%; ARD: n = 7, 50.0%), but the majority of these trials did not provide explicit reasons for this choice (GSD: n = 7, 100.0%; ADFD: n = 7, 87.5%; ARD: n = 5, 71.4%). More than half (n = 76, 59.4%) of trials did not mention the accessibility of supporting documents, and two-thirds (n = 86, 67.2%) did not state the establishment of independent data monitoring committees (IDMCs). Moreover, unplanned adjustments were observed during the conduct of one-sixth adaptive trials (n = 22, 17.2%). Based on our findings, we provide 14 recommendations for improving adaptive trials in the future.

CONCLUSION

Substantial improvements were needed in methods of adaptive trials, particularly in the areas of interim analysis, the establishment of independent data monitoring committees, and unplanned adjustments. In this study, we offer recommendations from both general and specific aspects for researchers to carefully design, conduct, and analyze adaptive trials.

Research Reviews: Advances in methods for evaluating child and adolescent mental health interventions

BACKROUND

The evidence base for interventions for child mental health and neurodevelopment is weak and the current capacity for rigorous evaluation limited. We describe some of the challenges that make this field particularly difficult and expensive for evaluation studies.

METHODS

We describe and review the use of novel study designs and analysis methodology for their potential to improve this situation.

RESULTS

While several novel designs appeared ill-suited to our field, systematic review found others that offered potential but had yet to be widely adopted, some not at all.

CONCLUSIONS

While funding is inevitably a constraint, we argue that improvements in the evidence base of both current and new treatments will only be achieved by the adoption of a number of these new technologies and study designs, the consistent application of rigorous constructive but demanding standards, and the engagement of the public, patients, clinical and research services to build a design, recruitment, and analysis infrastructure.

Demonstration of a 'leapfrog' randomized controlled trial as a method to accelerate the development and optimization of psychological interventions

BACKGROUND

The scale of the global mental health burden indicates the inadequacy not only of current treatment options, but also the pace of the standard treatment development process. The 'leapfrog' trial design is a newly-developed simple Bayesian adaptive trial design with potential to accelerate treatment development. A first leapfrog trial was conducted to provide a demonstration and test feasibility, applying the method to a low-intensity internet-delivered intervention targeting anhedonia.

METHODS

At the start of this online, single-blind leapfrog trial, participants self-reporting depression were randomized to an initial control arm comprising four weeks of weekly questionnaires, or one of two versions of a four-week cognitive training intervention, imagery cognitive bias modification (imagery CBM). Intervention arms were compared to control on an ongoing basis via sequential Bayesian analyses, based on a primary outcome of anhedonia at post-intervention. Results were used to eliminate and replace arms, or to promote them to become the control condition based on pre-specified Bayes factor and sample size thresholds. Two further intervention arms (variants of imagery CBM) were added into the trial as it progressed.

RESULTS

N = 188 participants were randomized across the five trial arms. The leapfrog methodology was successfully implemented to identify a 'winning' version of the imagery CBM, i.e. the version most successful in reducing anhedonia, following sequential elimination of the other arms.

CONCLUSIONS

The study demonstrates feasibility of the leapfrog design and provides a foundation for its adoption as a method to accelerate treatment development in mental health. Registration: clinicaltrials.gov, NCT04791137.

A rapid review of community engagement and informed consent processes for adaptive platform trials and alternative design trials for public health emergencies

Background : Public Health Emergencies (PHE) demand expeditious research responses to evaluate new or repurposed therapies and prevention strategies. Alternative Design Trials (ADTs) and Adaptive Platform Trials (APTs) have enabled efficient large-scale testing of biomedical interventions during recent PHEs. Design features of these trials may have implications for engagement and/or informed consent processes. We aimed to rapidly review evidence on engagement and informed consent for ADTs and APTs during PHE to consider what (if any) recommendations can inform practice. Method : In 2022, we searched 8 prominent databases for relevant peer reviewed publications and guidelines for ADTs/APTs in PHE contexts. Articles were selected based on pre-identified inclusion and exclusion criteria. We reviewed protocols and informed consent documents for a sample of large platform trials and consulted with key informants from ADTs/APT trial teams. Data were extracted and summarised using narrative synthesis. Results : Of the 49 articles included, 10 were guidance documents, 14 discussed engagement, 10 discussed informed consent, and 15 discussed both. Included articles addressed ADTs delivered during the West African Ebola epidemic and APTs delivered during COVID-19. PHE clinical research guidance documents highlight the value of ADTs/APTs and the importance of community engagement, but do not provide practice-specific guidance for engagement or informed consent. Engagement and consent practice for ADTs conducted during the West African Ebola epidemic have been well-documented. For COVID-19, engagement and consent practice was described for APTs primarily delivered in high income countries with well-developed health service structures. A key consideration is strong communication of the complexity of trial design in clear, accessible ways. Conclusion: We highlight key considerations for best practice in community engagement and informed consent relevant to ADTs and APTs for PHEs which may helpfully be included in future guidance. Protocol: The review protocol is published online at Prospero on 15/06/2022: registration number CRD42022334170.

Platform trials

For the past few years, platform trials have experienced a significant increase, recently amplified by the COVID-19 pandemic. The implementation of a platform trial is particularly useful in certain pathologies, particularly when there is a significant number of drug candidates to be assessed, a rapid evolution of the standard of care or in situations of urgent need for evaluation, during which the pooling of protocols and infrastructure optimizes the number of patients to be enrolled, the costs, and the deadlines for carrying out the investigation. However, the specificity of platform trials raises methodological, ethical, and regulatory issues, which have been the subject of the round table and which are presented in this article. The round table was also an opportunity to discuss the complexity of sponsorship and data management related to the multiplicity of partners, funding, and governance of these trials, and the level of acceptability of their findings by the competent authorities.

Adaptive interventions to optimise the mobile phone-based smoking cessation support: study protocol for a sequential, multiple assignment, randomised trial (SMART)

BACKGROUND

Mobile health (mHealth) is promising in developing personalised smoking cessation interventions. By using an adaptive trial design, we aim to evaluate the effectiveness of personalised mHealth intervention in increasing smoking cessation.

METHODS

This study is a two-arm, parallel, accessor-blinded Sequential Multiple-Assignment Randomised Trial (SMART) that randomises 1200 daily cigarette smokers from 70 community sites at two timepoints. In the first phase, participants receive brief cessation advice plus referral assistance to smoking cessation services and are randomly allocated to receive personalised instant messaging (PIM) or regular instant messaging (RIM). In the second phase, PIM participants who are non-responders (i.e. still smoking at 1 month) are randomised to receive either optional combined interventions (multi-media messages, nicotine replacement therapy sampling, financial incentive for active referral, phone counselling, and family/peer support group chat) or continued-PIM. Non-responders in the RIM group are randomised to receive PIM or continued-RIM. Participants who self-report quitting smoking for 7 days or longer at 1 month (responders) in both groups continue to receive the intervention assigned in phase 1. The primary outcomes are biochemical abstinence validated by exhaled carbon monoxide (< 4 ppm) and salivary cotinine (< 10 ng/ml) at 3 and 6 months from treatment initiation. Intention-to-treat analysis will be adopted.

DISCUSSION

This is the first study using a SMART design to evaluate the effect of adaptive mHealth intervention on abstinence in community-recruited daily smokers. If found effective, the proposed intervention will inform the development of adaptive smoking cessation treatment and benefits smokers non-responding to low-intensity mHealth support.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03992742 . Registered on 20 June 2019.

Should RECOVERY have used response adaptive randomisation? Evidence from a simulation study

Background

The Randomised Evaluation of COVID-19 Therapy (RECOVERY) trial is aimed at addressing the urgent need to find effective treatments for patients hospitalised with suspected or confirmed COVID-19. The trial has had many successes, including discovering that dexamethasone is effective at reducing COVID-19 mortality, the first treatment to reach this milestone in a randomised controlled trial. Despite this, it continues to use standard or ‘fixed’ randomisation to allocate patients to treatments. We assessed the impact of implementing response adaptive randomisation within RECOVERY using an array of performance measures, to learn if it could be beneficial going forward. This design feature has recently been implemented within the REMAP-CAP platform trial.

Methods

Trial data was simulated to closely match the data for patients allocated to standard care, dexamethasone, hydroxychloroquine, or lopinavir-ritonavir in the RECOVERY trial from March-June 2020, representing four out of five arms tested throughout this period. Trials were simulated in both a two-arm trial setting using standard care and dexamethasone, and a four-arm trial setting utilising all above treatments. Two forms of fixed randomisation and two forms of response-adaptive randomisation were tested. In the two-arm setting, response-adaptive randomisation was implemented across both trial arms, whereas in the four-arm setting it was implemented in the three non-standard care arms only. In the two-arm trial, randomisation strategies were performed at the whole trial level as well as within three pre-specified patient subgroups defined by patients’ respiratory support level.

Results

All response-adaptive randomisation strategies led to more patients being given dexamethasone and a lower mortality rate in the trial. Subgroup specific response-adaptive randomisation reduced mortality rates even further. In the two-arm trial, response-adaptive randomisation reduced statistical power compared to FR, with subgroup level adaptive randomisation exhibiting the largest power reduction. In the four-arm trial, response-adaptive randomisation increased statistical power in the dexamethasone arm but reduced statistical power in the lopinavir arm. Response-adaptive randomisation did not induce any meaningful bias in treatment effect estimates nor did it cause any inflation in the type 1 error rate.

Conclusions

Using response-adaptive randomisation within RECOVERY could have increased the number of patients receiving the optimal COVID-19 treatment during the trial, while reducing the number of patients needed to attain the same study power as the original study. This would likely have reduced patient deaths during the trial and lead to dexamethasone being declared effective sooner. Deciding how to balance the needs of patients within a trial and future patients who have yet to fall ill is an important ethical question for the trials community to address. Response-adaptive randomisation deserves to be considered as a design feature in future trials of COVID-19 and other diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01691-w.

Texts don't nudge: An adaptive trial to prevent the spread of COVID-19 in India

We conduct an adaptive randomized controlled trial to evaluate the impact of a SMS-based information campaign on the adoption of social distancing and handwashing in rural Bihar, India, six months into the COVID-19 pandemic. We test 10 arms that vary in delivery timing and message framing, changing content to highlight gains or losses for either one's own family or community. We identify the optimal treatment separately for each targeted behavior by adaptively allocating shares across arms over 10 experimental rounds using exploration sampling. Based on phone surveys with nearly 4,000 households and using several elicitation methods, we do not find evidence of impact on knowledge or adoption of preventive health behavior, and our confidence intervals cannot rule out positive effects as large as 5.5 percentage points, or 16%. Our results suggest that SMS-based information campaigns may have limited efficacy after the initial phase of a pandemic.

Clinical research methodology process: what is changing with COVID-19?

The repercussions of the pandemic in progress on clinical research have been the systematic interruption of ongoing research and the explosion of fragmented, uncoordinated, often technically insufficient anti-COVID-19 research. Networks of expert centres have emerged setting up well-structured research, adopting much more efficient and aggressive designs than traditional ones. Adaptive designs, characterized by flexibility and mouldability even in the course of studies, which is essential in an epidemic with thousands of simultaneous studies aimed at the same objectives. Some studies are structured with networks of hospitals around guidance centres, such as RECOVERY (Oxford University, UK) and SOLIDARITY (WHO, 30 countries); others with networks of expert centres mostly organized in a combined model: some expert centres test new molecules in Phase 2 in a limited number of patients, and orient promising ones towards connected networks for Phase 3. Cortisones and tentatively cytokines are acquired in the official recommendation. Another emerging model is the pragmatic trial, also called, more expressively, 'remote' or 'virtual'. So it is in fact: the web replaces the direct link between patients and doctors/research operators (CROs included), behind which there will be omnipresent big-techs.

Design of the National Adaptive Trial for PTSD-related Insomnia (NAP Study), VA Cooperative Study Program (CSP) #2016

There are currently no validated pharmacotherapies for posttraumatic stress disorder (PTSD)-related insomnia. The purpose of the National Adaptive Trial for PTSD-Related Insomnia (NAP Study) is to efficiently compare to placebo the effects of three insomnia medications with different mechanisms of action that are already prescribed widely to veterans diagnosed with PTSD within U.S. Department of Veterans Affairs (VA) Medical Centers. This study plans to enroll 1224 patients from 34 VA Medical Centers into a 12- week prospective, randomized placebo-controlled clinical trial comparing trazodone, eszopiclone, and gabapentin. The primary outcome measure is insomnia, assessed with the Insomnia Severity Index. A novel aspect of this study is its adaptive design. At the recruitment midpoint, an interim analysis will be conducted to inform a decision to close recruitment to any "futile" arms (i.e. arms where further recruitment is very unlikely to yield a significant result) while maintaining the overall study recruitment target. This step could result in the enrichment of the remaining study arms, enhancing statistical power for the remaining comparisons to placebo. This study will also explore clinical, actigraphic, and biochemical predictors of treatment response that may guide future biomarker development. Lastly, due to the COVID-19 pandemic, this study will allow the consenting process and follow-up visits to be conducted via video or phone contact if in-person meetings are not possible. Overall, this study aims to identify at least one effective pharmacotherapy for PTSD-related insomnia, and, perhaps, to generate definitive negative data to reduce the use of ineffective insomnia medications. NATIONAL CLINICAL TRIAL (NCT) IDENTIFIED NUMBER: NCT03668041.

Age-based targeting of biannual azithromycin distribution for child survival in Niger: an adaptive cluster-randomized trial protocol (AVENIR)

BACKGROUND

Biannual distribution of azithromycin to children 1-59 months old reduced mortality by 14% in a cluster-randomized trial. The World Health Organization has proposed targeting this intervention to the subgroup of children 1-11 months old to reduce selection for antimicrobial resistance. Here, we describe a trial designed to determine the impact of age-based targeting of biannual azithromycin on mortality and antimicrobial resistance.

METHODS

AVENIR is a cluster-randomized, placebo-controlled, double-masked, response-adaptive large simple trial in Niger. During the 2.5-year study period, 3350 communities are targeted for enrollment. In the first year, communities in the Dosso region will be randomized 1:1:1 to 1) azithromycin 1-11: biannual azithromycin to children 1-11 months old with placebo to children 12-59 months old, 2) azithromycin 1-59: biannual azithromycin to children 1-59 months old, or 3) placebo: biannual placebo to children 1-59 months old. Regions enrolled after the first year will be randomized with an updated allocation based on the probability of mortality in children 1-59 months in each arm during the preceding study period. A biannual door-to-door census will be conducted to enumerate the population, distribute azithromycin and placebo, and monitor vital status. Primary mortality outcomes are defined as all-cause mortality rate (deaths per 1000 person-years) after 2.5 years from the first enrollment in 1) children 1-59 months old comparing the azithromycin 1-59 and placebo arms, 2) children 1-11 months old comparing the azithromycin 1-11 and placebo arm, and 3) children 12-59 months in the azithromycin 1-11 and azithromycin 1-59 arms. In the Dosso region, 50 communities from each arm will be followed to monitor antimicrobial resistance. Primary resistance outcomes will be assessed after 2 years of distributions and include 1) prevalence of genetic determinants of macrolide resistance in nasopharyngeal samples from children 1-59 months old, and 2) load of genetic determinants of macrolide resistance in rectal samples from children 1-59 months old.

DISCUSSION

As high-mortality settings consider this intervention, the results of this trial will provide evidence to support programmatic and policy decision-making on age-based strategies for azithromycin distribution to promote child survival.

TRIAL REGISTRATION

This trial was registered on January 13, 2020 (clinicaltrials.gov: NCT04224987 ).

Implementation of the Randomized Embedded Multifactorial Adaptive Platform for COVID-19 (REMAP-COVID) trial in a US health system-lessons learned and recommendations

Background

The Randomized Embedded Multifactorial Adaptive Platform for COVID-19 (REMAP-COVID) trial is a global adaptive platform trial of hospitalized patients with COVID-19. We describe implementation at the first US site, the UPMC health system, and offer recommendations for implementation at other sites.

Methods

To implement REMAP-COVID, we focused on six major areas: engaging leadership, trial embedment, remote consent and enrollment, regulatory compliance, modification of traditional trial management procedures, and alignment with other COVID-19 studies.

Results

We recommend aligning institutional and trial goals and sharing a vision of REMAP-COVID implementation as groundwork for learning health system development. Embedment of trial procedures into routine care processes, existing institutional structures, and the electronic health record promotes efficiency and integration of clinical care and clinical research. Remote consent and enrollment can be facilitated by engaging bedside providers and leveraging institutional videoconferencing tools. Coordination with the central institutional review board will expedite the approval process. Protocol adherence, adverse event monitoring, and data collection and export can be facilitated by building electronic health record processes, though implementation can start using traditional clinical trial tools. Lastly, establishment of a centralized institutional process optimizes coordination of COVID-19 studies.

Conclusions

Implementation of the REMAP-COVID trial within a large US healthcare system is feasible and facilitated by multidisciplinary collaboration. This investment establishes important groundwork for future learning health system endeavors.

Trial registration

NCT02735707. Registered on 13 April 2016.

Rationale and design of the Novel Uses of adaptive Designs to Guide provider Engagement in Electronic Health Records (NUDGE-EHR) pragmatic adaptive randomized trial: a trial protocol

BACKGROUND

The prescribing of high-risk medications to older adults remains extremely common and results in potentially avoidable health consequences. Efforts to reduce prescribing have had limited success, in part because they have been sub-optimally timed, poorly designed, or not provided actionable information. Electronic health record (EHR)-based tools are commonly used but have had limited application in facilitating deprescribing in older adults. The objective is to determine whether designing EHR tools using behavioral science principles reduces inappropriate prescribing and clinical outcomes in older adults.

METHODS

The Novel Uses of Designs to Guide provider Engagement in Electronic Health Records (NUDGE-EHR) project uses a two-stage, 16-arm adaptive randomized pragmatic trial with a "pick-the-winner" design to identify the most effective of many potential EHR tools among primary care providers and their patients ≥ 65 years chronically using benzodiazepines, sedative hypnotic ("Z-drugs"), or anticholinergics in a large integrated delivery system. In stage 1, we randomized providers and their patients to usual care (n = 81 providers) or one of 15 EHR tools (n = 8 providers per arm) designed using behavioral principles including salience, choice architecture, or defaulting. After 6 months of follow-up, we will rank order the arms based upon their impact on the trial's primary outcome (for both stages): reduction in inappropriate prescribing (via discontinuation or tapering). In stage 2, we will randomize (a) stage 1 usual care providers in a 1:1 ratio to one of the up to 5 most promising stage 1 interventions or continue usual care and (b) stage 1 providers in the unselected arms in a 1:1 ratio to one of the 5 most promising interventions or usual care. Secondary and tertiary outcomes include quantities of medication prescribed and utilized and clinically significant adverse outcomes.

DISCUSSION

Stage 1 launched in October 2020. We plan to complete stage 2 follow-up in December 2021. These results will advance understanding about how behavioral science can optimize EHR decision support to improve prescribing and health outcomes. Adaptive trials have rarely been used in implementation science, so these findings also provide insight into how trials in this field could be more efficiently conducted.

TRIAL REGISTRATION

Clinicaltrials.gov ( NCT04284553 , registered: February 26, 2020).

muLTi-Arm Therapeutic study in pre-ICu patients admitted with Covid-19-Experimental drugs and mechanisms (TACTIC-E): A structured summary of a study protocol for a randomized controlled trial

Objectives

To determine if a specific intervention reduces the composite of progression of patients with COVID-19-related disease to organ failure or death as measured by time to incidence of any one of the following: death, invasive mechanical ventilation, ECMO, cardiovascular organ support (inotropes or balloon pump), or renal failure (estimated Cockcroft Gault creatinine clearance <15ml/min).

Trial design

Randomised, parallel arm, open-label, adaptive platform Phase 2/3 trial of potential disease modifying therapies in patients with late stage 1/stage 2 COVID-19-related disease, with a diagnosis based either on a positive assay or high suspicion of COVID-19 infection by clinical, laboratory and radiological assessment.

Participants

Patients aged 18 and over, with a clinical picture strongly suggestive of COVID-19-related disease (with/without a positive COVID-19 test) AND a risk count (as defined below) >3 OR ≥3 if risk count includes “Radiographic severity score >3”. A risk count is calculated by the following features on admission (1 point for each): radiographic severity score >3, male gender, non-white ethnicity, diabetes, hypertension, neutrophils >8.0 x10⁹/L, age >40 years and CRP >40 mg/L.

Patients should be considered an appropriate subject for intervention with immunomodulatory or other disease modifying agents in the opinion of the investigator and are able to swallow capsules or tablets. The complete inclusion and exclusion criteria as detailed in the Additional file 1 should be fulfilled. Drug specific inclusion and exclusion criteria will also be applied to the active arms. Patients will be enrolled prior to the need for invasive mechanical ventilation, cardiac or renal support. Participants will be recruited across multiple centres in the UK including initially at Cambridge University Hospitals NHS Foundation Trust and St George’s University NHS Foundation Trust. Other centres will be approached internationally in view of the evolving pandemic.

Intervention and comparator

There is increasing evidence of the role of immunomodulation in altering the course of COVID-19. Additionally, various groups have demonstrated the presence of pulmonary shunting in patients with COVID-19 as well as other cardiovascular complications. TACTIC-E will assess the efficacy of the novel immunomodulatory agent EDP1815 versus the approved cardio-pulmonary drugs, Dapagliflozin in combination with Ambrisentan versus the prevailing standard of care.

EDP1815 will be given as 2 capsules twice daily (1.6 x 10¹¹ cells) for up to 7 days with the option to extend up to 14 days at the discretion of the principal investigator or their delegate, if the patient is felt to be clinically responding to treatment, is tolerating treatment, and is judged to be likely to benefit from a longer treatment course. Ambrisentan 5mg and Dapagliflozin 10mg will be given in combination once daily orally for up to maximum of 14 days. Patients will be randomised in a 1:1:1 ratio across treatments. Each active arm will be compared with standard of care alone. Additional arms may be added as the trial progresses. No comparisons will be made between active arms in this platform trial.

Main outcomes

The primary outcome is the incidence (from baseline up to Day 14) to the occurrence of the any one of the following events: death, invasive mechanical ventilation, extra corporeal membrane oxygenation, cardiovascular organ support (inotropes or balloon pump), or renal failure (estimated Cockcroft Gault creatinine clearance <15ml/min).

Randomisation

Eligible patients will be randomised using a central web-based randomisation service (Sealed Envelope) in a 1:1:1 ratio, stratified by site to one of the treatment arms or standard of care.

Blinding (masking)

This is an open-label trial. Data analysis will not be blinded.

Numbers to be randomised (sample size)

There is no fixed sample size for this study. There will be an early biomarker-based futility analysis performed at a point during the study. If this biomarker futility analysis is not conclusive, then a second futility analysis based on clinical endpoints will be performed after approximately 125 patients have been recruited per arm. Provisionally, further analyses of clinical endpoints will be performed after 229 patients per active arm and later 469 patients per arm have been recruited. Further additional analyses may be triggered by the independent data monitoring committee.

Trial Status

TACTIC-E Protocol version number 1.0 date May 27^th, 2020. Recruitment starts on the 3^rd of July 2020. The end trial date will be 18 months after the last patient’s last visit and cannot be accurately predicted at this time.

Trial registration

Registered on EU Clinical Trials Register EudraCT Number: 2020-002229-27 registered: 9 June 2020.

The trial was also registered on ClinicalTrials.gov (NCT04393246) on 19 May 2020.

Full protocol

The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Efficient Adaptive Designs for Clinical Trials of Interventions for COVID-19

The COVID-19 pandemic has led to an unprecedented response in terms of clinical research activity. An important part of this research has been focused on randomized controlled clinical trials to evaluate potential therapies for COVID-19. The results from this research need to be obtained as rapidly as possible. This presents a number of challenges associated with considerable uncertainty over the natural history of the disease and the number and characteristics of patients affected, and the emergence of new potential therapies. These challenges make adaptive designs for clinical trials a particularly attractive option. Such designs allow a trial to be modified on the basis of interim analysis data or stopped as soon as sufficiently strong evidence has been observed to answer the research question, without compromising the trial's scientific validity or integrity. In this article, we describe some of the adaptive design approaches that are available and discuss particular issues and challenges associated with their use in the pandemic setting. Our discussion is illustrated by details of four ongoing COVID-19 trials that have used adaptive designs.

Repurposed immunomodulatory drugs for Covid-19 in pre-ICu patients - mulTi-Arm Therapeutic study in pre-ICu patients admitted with Covid-19 - Repurposed Drugs (TACTIC-R): A structured summary of a study protocol for a randomised controlled trial

OBJECTIVES

To determine if a specific immunomodulatory intervention reduces progression of COVID-19-related disease to organ failure or death, compared to standard of care (SoC).

TRIAL DESIGN

Randomised, parallel 3-arm (1:1:1 ratio), open-label, Phase IV platform trial of immunomodulatory therapies in patients with late stage 1 or stage 2 COVID-19-related disease, with a diagnosis based either on a positive assay or high suspicion of COVID-19 infection by clinical and/or radiological assessment.

PARTICIPANTS

Patients aged 18 and over, with a clinical picture strongly suggestive of COVID-19-related disease (with/without a positive COVID-19 test) AND a Risk count (as defined below) >3 OR ≥3 if risk count includes "Radiographic severity score >3". A risk count is calculated by the following features on admission (1 point for each): radiographic severity score >3, male gender, non-white ethnicity, diabetes, hypertension, neutrophils >8.0 x109/L, age >40 years and CRP >40 mg/L. Patients should be considered an appropriate subject for intervention with immunomodulatory therapies in the opinion of the investigator and be able to be maintained on venous thromboembolism prophylaxis during the inpatient dosing period, according to local guidelines. The complete inclusion and exclusion criteria as detailed in the additional file 1 should be fulfilled. Patients will be enrolled prior to the need for invasive mechanical ventilation, cardiac or renal support. Participants will be recruited across multiple centres including initially at Cambridge University Hospitals NHS Foundation Trust, King's College Hospital NHS Foundation Trust, Guy's and St Thomas' NHS Foundation Trust, University Hospital of Wales, Gloucestershire Royal Hospitals NHS Foundation Trust and The Royal Wolverhampton NHS Trust.

INTERVENTION AND COMPARATOR

Each active comparator arm will be compared against standard of care (SoC). The immunomodulatory drugs were selected from a panel of licenced candidates by a drug evaluation committee, which considered potential efficacy, potential toxicity, scalability and novelty of each strategy. The initial active arms comprise baricitinib and ravulizumab. Baricitinib will be given 4 mg orally (once daily (OD)) on days 1-14 or until day of discharge. The dose will be reduced to 2 mg OD for patients aged > 75 years and those with an estimated Cockcroft Gault creatinine clearance of 30-60 ml/min. Ravulizumab will be administered intravenously once according to the licensed weight-based dosing regimen (see Additional file 1). Each active arm will be compared with standard of care alone. No comparisons will be made between active arms in this platform trial.

MAIN OUTCOMES

The primary outcome is the incidence (from baseline up to Day 14) of any one of the events (whichever comes first): death, invasive mechanical ventilation, extra corporeal membrane oxygenation, cardiovascular organ support (inotropes or balloon pump), or renal failure (estimated Cockcroft Gault creatinine clearance <15ml/min).

RANDOMISATION

Eligible patients will be randomised using a central web-based randomisation service (Sealed Envelope) in a 1:1:1 ratio, stratified by site to one of the treatment arms or SoC.

BLINDING (MASKING)

This is an open-label trial. Data analysis will not be blinded.

NUMBERS TO BE RANDOMISED (SAMPLE SIZE)

There is no fixed sample size for this study. Serial interim analyses will be triggered by an Independent Data Monitoring Committee (IDMC), including analysis after 125 patients are recruited to each arm, 375 in total assuming 3 arms. Additional interim analyses are projected after 229 patients per arm, and potentially then after 469 per arm, but additional analyses may be triggered by the IDMC.

TRIAL STATUS

TACTIC-R Protocol version number 2.0 date May 20, 2020, recruitment began May 7, 2020 and the end trial will be the date 18 months after the last patient's last visit. The recruitment end date cannot yet be accurately predicted.

TRIAL REGISTRATION

Registered on EU Clinical Trials Register EudraCT Number: 2020-001354-22 Registered: 6 May 2020 It was registered on ClinicalTrials.gov ( NCT04390464 ) and on ISRCTN (ISRCTN11188345) FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Treatment of pustular psoriasis with anakinra: a statistical analysis plan for stage 1 of an adaptive two-staged randomised placebo-controlled trial

BACKGROUND

Palmoplantar pustulosis (PPP) is a rare, chronic inflammatory skin disease. It is known to affect quality of life at a level comparable to that from major medical and psychiatric illness, yet current treatment options are remarkably limited. Recent evidence however suggests that interleukin-1 (IL-1) blockade with anakinra will deliver therapeutic benefit in PPP.

METHODS

Anakinra for Pustular psoriasis: Response in a Controlled Trial (APRICOT) is a two-staged, adaptive, double-blind, randomised placebo-controlled trial which aims to test the hypothesis that IL-1 blockade with anakinra will deliver therapeutic benefit in PPP. During stage 1 a total of 24 patients will be randomised (1:1) to receive either placebo or anakinra. The two candidate primary outcomes are fresh pustule count (across palms and soles) and the Palmoplantar Pustulosis Area and Severity Index (PPPASI) score, recorded at baseline and at weeks 1, 4 and 8. Analysis at the end of stage 1 will compare treatment arms to ensure sufficient efficacy and safety in order to progress to stage 2. The primary outcome for stage 2 will also be identified following an assessment of the reliability and discriminative ability of fresh pustule count and PPPASI. The trial is powered to detect efficacy and will recruit an additional 40 patients in stage 2 (n = 64 in total). Analysis will follow the intention-to-treat principle and analyse patients as randomised.

DISCUSSION

This manuscript describes the important features of the small population trial design for APRICOT and the pre-specified statistical analysis plan for stage 1. The statistical analysis plan has been developed prior to data extraction and in compliance with international guidelines. It will increase the transparency of the data analysis for the APRICOT trial. The findings of the trial will help to clarify the role of anakinra in the treatment of PPP.

TRIAL REGISTRATION

ISCRTN, ISCRTN13127147 . Registered on 1 August 2016. EudraCT Number 2015-003600-23 . Registered on 1 April 2016.

A small population, randomised, placebo-controlled trial to determine the efficacy of anakinra in the treatment of pustular psoriasis: study protocol for the APRICOT trial

Background

Palmoplantar pustulosis is a rare but painful and debilitating disease. It consistently ranks the highest of all psoriasis phenotypic variants in terms of symptoms and functional impairment. Management of plaque-type psoriasis has been revolutionised in the last 10 years with the advent of biologic therapies, but treatment options for pustular psoriasis remain profoundly limited. On the basis of mechanistic findings which suggest a key pathogenic role for interleukin (IL)-1 in pustular psoriasis, we hypothesise that anakinra (IL-1 blockade) will be an efficacious treatment for pustular psoriasis.

Methods/design

We will conduct a two-stage, adaptive, double-blind, randomised, placebo-controlled trial to test the hypothesis that anakinra, self-administered daily by subcutaneous injection over 8 weeks, will deliver therapeutic benefit in palmoplantar pustular psoriasis, a localised form of pustular psoriasis typically involving the palms and/or soles. Safety outcomes will be collected for 20 weeks. A total of 64 participants will be randomised to anakinra or placebo in a 1:1 ratio. At the end of stage 1, a decision to progress to stage 2 will be made. This decision will take place after 24 participants have been randomised and followed for 8 weeks and will be based on the ordering of the observed mean outcome values in both treatment arms. At the end of stage 1, the reliability of outcome measurements and method to collect the data will also be assessed, and the primary outcome will be confirmed for stage 2.

Discussion

We have undertaken an adaptive approach in which we will gain proof-of-concept data prior to completing a powered efficacy trial because pustular psoriasis is a rare disease, no validated outcome measures to detect change exist, and limited safety data for anakinra exist in this population. To our knowledge, this will be the first randomised controlled trial that will provide valuable evidence for the efficacy and safety of IL-1 blockade for treatment in pustular psoriasis.

Trial registration

ISRCTN13127147. Registered on 1st August 2016.

EudraCT, 2015-003600-23. Registered on 1st April 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2841-y) contains supplementary material, which is available to authorized users.

Design of a Bayesian adaptive phase 2 proof-of-concept trial for BAN2401, a putative disease-modifying monoclonal antibody for the treatment of Alzheimer's disease

Introduction

Recent failures in phase 3 clinical trials in Alzheimer's disease (AD) suggest that novel approaches to drug development are urgently needed. Phase 3 risk can be mitigated by ensuring that clinical efficacy is established before initiating confirmatory trials, but traditional phase 2 trials in AD can be lengthy and costly.

Methods

We designed a Bayesian adaptive phase 2, proof-of-concept trial with a clinical endpoint to evaluate BAN2401, a monoclonal antibody targeting amyloid protofibrils. The study design used dose response and longitudinal modeling. Simulations were used to refine study design features to achieve optimal operating characteristics.

Results

The study design includes five active treatment arms plus placebo, a clinical outcome, 12-month primary endpoint, and a maximum sample size of 800. The average overall probability of success is ≥80% when at least one dose shows a treatment effect that would be considered clinically meaningful. Using frequent interim analyses, the randomization ratios are adapted based on the clinical endpoint, and the trial can be stopped for success or futility before full enrollment.

Discussion

Bayesian statistics can enhance the efficiency of analyzing the study data. The adaptive randomization generates more data on doses that appear to be more efficacious, which can improve dose selection for phase 3. The interim analyses permit stopping as soon as a predefined signal is detected, which can accelerate decision making. Both features can reduce the size and duration of the trial. This study design can mitigate some of the risks associated with advancing to phase 3 in the absence of data demonstrating clinical efficacy. Limitations to the approach are discussed.

The Add-Arm Design for Unimodal Response Curve with Unknown Mode

In a classical drop-loser (or drop-arm) design, patients are randomized into all arms (doses) and at the interim analysis, inferior arms are dropped. Therefore, compared to the traditional dose-finding design, this adaptive design can reduce the sample size by not carrying over all doses to the end of the trial or dropping the losers earlier. However, all the doses have to be explored. For unimodal (including linear or umbrella) response curves, we proposed an effective dose-finding design that allows adding arms at the interim analysis. The trial design starts with two arms, depending on the response of the two arms and the unimodality assumption; we can decide which new arms to be added. This design does not require exploring all arms (doses) to find the best responsive dose; therefore, it can further reduce the sample size from the drop-loser design by as much as 10-20%.

Single-patient (n-of-1) trials: a pragmatic clinical decision methodology for patient-centered comparative effectiveness research

OBJECTIVE

To raise awareness among clinicians and epidemiologists that single-patient (n-of-1) trials are potentially useful for informing personalized treatment decisions for patients with chronic conditions.

STUDY DESIGN AND SETTING

We reviewed the clinical and statistical literature on methods and applications of single-patient trials and then critically evaluated the needs for further methodological developments.

RESULTS

Existing literature reports application of 2,154 single-patient trials in 108 studies for diverse clinical conditions; various recent commentaries advocate for wider application of such trials in clinical decision making. Preliminary evidence from several recent pilot acceptability studies suggests that single-patient trials have the potential for widespread acceptance by patients and clinicians as an effective modality for increasing the therapeutic precision. Bayesian and adaptive statistical methods hold promise for increasing the informational yield of single-patient trials while reducing participant burden, but are not widely used. Personalized applications of single-patient trials can be enhanced through further development and application of methodologies on adaptive trial design, stopping rules, network meta-analysis, washout methods, and methods for communicating trial findings to patients and clinicians.

CONCLUSIONS

Single-patient trials may be poised to emerge as an important part of the methodological armamentarium for comparative effectiveness research and patient-centered outcomes research. By permitting direct estimation of individual treatment effects, they can facilitate finely graded individualized care, enhance therapeutic precision, improve patient outcomes, and reduce costs.

Use of Bayesian statistics in drug development: Advantages and challenges

Mainly, two statistical methodologies are applicable to the design and analysis of clinical trials: frequentist and Bayesian. Most traditional clinical trial designs are based on frequentist statistics. In frequentist statistics prior information is utilized formally only in the design of a clinical trial but not in the analysis of the data. On the other hand, Bayesian statistics provide a formal mathematical method for combining prior information with current information at the design stage, during the conduct of the trial, and at the analysis stage. It is easier to implement adaptive trial designs using Bayesian methods than frequentist methods. The Bayesian approach can also be applied for post-marketing surveillance purposes and in meta-analysis. The basic tenets of good trial design are same for both Bayesian and frequentist trials. It has been recommended that the type of analysis to be used (Bayesian or frequentist) should be chosen beforehand. Switching to an analysis method that produces a more favorable outcome after observing the data is not recommended.