Study Setting
The CLEAR sites will include at least 16 National Health Service hospitals in the UK with access to a BE population managed according to BTS guidelines. Sites will include those which are part of the BRONCH-UK /or EMBARC research network (29), and additional sites will be chosen from the Northern Ireland Clinical research Network (NICRN)/National Institute for Health Research Clinical Research Network (NIHR CRN) portfolio if required. The current list of study sites is in Additional File 5.
Internal pilot study
The main trial will be preceded by an 8-month internal pilot study in 10 sites, which will follow the processes described for the main trial with a target recruitment of 60 patients. This internal pilot will be used to confirm recruitment rates, protocol compliance and data collection methods.
Characteristics of Participants
Patients will be eligible to participate in CLEAR if they fulfil the following inclusion/exclusion criteria: diagnosis of BE on computerised tomography/high-resolution computerised tomography (CT/HRCT), BE is the primary respiratory diagnosis, two or more pulmonary exacerbations in the last year requiring antibiotics (including patient reported exacerbations), production of daily sputum, stable for 14 or more days before first study visit with no changes to treatment, willing to continue any other existing chronic medication through the study, female subjects must be either surgically sterile, postmenopausal or agree to use effective contraception during the treatment period of the trial.
Exclusion criteria: <18 years’ old, cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), current smokers, female ex-smokers with greater than 20 pack years and male ex-smokers with greater than 25 pack years, FEV1 <30%, if being treated with long term macrolides on treatment for less than one month before joining study, regular isotonic saline, HTS, carbocisteine or any mucoactives within the past 30 days, known intolerance or contraindication to HTS or carbocisteine, contraindications or special warnings for the use of carbocisteine (active peptic ulceration, heredity galactose intolerance, the Lapp-Lactase deficiency, glucose-galactose malabsorption), unable to swallow oral capsules, women who are pregnant or lactating, participation in another clinical trial of an investigational medicinal product within 30 days. Patients currently using mucoactives can be considered for CLEAR if they stop these for at least 30 days before being assessed for eligibility.
Screening and informed consent
Written informed consent will be obtained by the site principal investigator or appropriately trained designee. All interested individuals who are eligible using the screening criteria will be given a participant information sheet and allowed as much time as necessary to consider the study. Informed consent will be obtained using standard procedures.
Intervention and Comparator
Intervention 1: Standard care and twice-daily nebulised HTS (MucoClear 6%, PARI Pharma). Participants will be instructed to administer a 1 x 4 mL ampoule twice daily for 52 weeks using the eFlow rapid nebuliser and eTrack controller (PARI Pharma).
Intervention 2: Standard care and carbocisteine (750 mg three-times-per-day until visit 3* reducing to 750 mg two times per day) over 52 weeks.
Intervention 3: Standard care and combination of twice-daily nebulised HTS (MucoClear 6%, PARI Pharma). Participants will be instructed to administer a 1 x 4 mL ampoule twice daily for 52 weeks using the eFlow rapid nebuliser eFlow rapid nebuliser and eTrack controller (PARI Pharma). They will also be given carbocisteine (750 mg of three times per day until visit 3* reducing to 750 mg twice per day) over 52 weeks.
Comparator: Standard care over 52 weeks. Patients in the standard care group will use airway clearance techniques in the management of their BE.
*Visit 3 occurs 8 weeks (±7 days) post the baseline assessment)
Concomitant Care
Sites in this study all follow BTS guidelines for management of BE. Any prescribed medication deemed necessary to provide adequate medical care to the patient is permitted, other than as stated in the study exclusion criteria. The use of mucoactives/isotonic saline outside allocated treatment is not permitted except for short periods during exacerbations.
Treatment Discontinuation
All patients allocated to a treatment group including HTS 6% will complete a drug response assessment prior to commencing HTS in accordance with a study specific guideline and if they do not pass this they will not continue on the study. Participants may withdraw from treatment at any time, without providing an explanation, or if discontinuation is considered by the medical team to be in the best interests of the patient. Anticipated reasons for withdrawal include: intercurrent significant illness, occurrence of intolerable side effects, patient request, protocol violations or decision that the study drug should be discontinued on safety grounds. A participant may be withdrawn from the study at the discretion of the Investigator due to safety concerns.
Study Drug Accountability, Compliance and Adherence
Patients will be asked to return any unused HTS 6% ampoules or carbocisteine at each study visit to facilitate drug accountability. Adherence to HTS will be monitored utilising the eFlow nebuliser system with eTrack controller (which records data on nebuliser usage including frequency of use, dosage and maintenance). For the two HTS groups (groups 1 and 3), study visit data from the eFlow nebuliser system with eTrack controller will be transferred to a Qualcomm Life 2Net Hub and subsequently to a secure cloud based platform. These data will not be reviewed and analysed until the end of the study, but weekly checks will be conducted by a person not involved in study delivery to ensure that the eFlow nebuliser system with eTrack controller is being used correctly and data are being transferred correctly.
Outcomes
The primary outcome measure is the mean number of exacerbations over 52 weeks from randomisation. Secondary outcome measures are disease specific HRQoL (respiratory symptoms of domain of QoL-B (30)), time to next exacerbation, number of days of antibiotics related to exacerbations, generic HRQoL (EQ-5D-5L (31)), measurement of health impairment using the St Georges Respiratory Questionnaire (SGRQ (2)), health service use, quality adjusted life years (QALYs), patient preferences for treatment, adverse events, lung function, and adherence to trial treatment over 52 weeks.
Spirometry
All patients will be provided with a hand held spirometers (mySpiroSense; PARI GmbH) to complete regular lung function tests at home (Additional File 3) as well as to record lung function at the beginning and end of an exacerbation. The mySpiroSense spirometer is a digital, self-calibrating instrument. Patients will bring the mySpiroSense to study visits so that its data can be imported to computers on site. The spirometry data can be viewed using the SpiroSensePro software and additionally the database can be transformed and exported as a Microsoft Excel file (.xls) and viewed.
Exacerbation Management
During the treatment period, if patients have symptoms of exacerbation for 48 hours or feel that they require antibiotic therapy, they will be asked to call the study team. Exacerbations will be defined as per the recent consensus (32). A comprehensive exacerbation management plan is detailed in Additional File 2. In general, patients will have rescue medication at home to facilitate management of exacerbations remotely. The trial will use an adjudication panel to categorise exacerbations.
Respiratory and Systemic Symptoms Questionnaire (RSSQ)
A member of the research team will administer the RSSQ questionnaire at each study visit to capture changes in the predefined signs and symptoms relative to normal day-to-day fluctuations (33). It covers arrange of patient reported outcomes relating to cough, sputum, haemoptysis dypsnea, lethargy, sinuses, appetite and fever (34). Modified versions of the RSSQ will be used to capture details of potential exacerbations reported between study visits.
Health-Related Quality of Life (HRQoL) questionnaires
Three HRQoL questionnaires will be used: QoL-B, SGRQ and EQ-5D-5L. The QoL-B assesses symptoms, functioning and health-related quality of life specific to patients with BE (30, 35, 36). The SGRQ measure health impairment (2, 35). The EQ-5D-5L provides a simple descriptive profile and a single index value for health status (31).
Health Service Use Questionnaire
A questionnaire and log will capture participant’s health service use over the study period, including details of prescribed medications (including antibiotics). This will be used for the health economic analysis.
Treatment Satisfaction Questionnaire for Medication
At each study visit, participants (except those randomised to standard care group) will be asked what they think about the effectiveness, side effects and convenience experienced when using the medication over the last two to three weeks, or since they last used it. Patients assigned to the group combining HTS and carbocisteine (group 3) will be asked to complete separate questionnaires for each treatment.
Schedule of Assessments
All patients will be evaluated during the study according to the schedule of assessments outlined in Figure 1 and Table 1.
Sample Size
The required sample size is 380 patients including the internal pilot. Based on the primary outcome of mean exacerbations during 52 weeks and a pooled standard deviation of 0.9 exacerbations (37), and assuming the mean number of exacerbations in the control group is 0.7, 216 patients would be sufficient to detect a mean difference in exacerbation rate between groups of 0.4 with 90% power and at the 5% significance level. To allow for a potential interaction between the two interventions, 50% inflation has been included, to 324 patients. Further, compensating for 15% dropout gives a total of 380 patients (95 in each of the four groups). In regard to secondary outcomes, this sample size would provide over 90% power to detect a minimally important difference of 8 points for the QoL-B scale (standard deviation of 18) at the 5% significance level (18, 30) and a 75% increase in median time to exacerbation at 98% power. It would also be sufficient to detect a medium effect size for the other secondary outcomes, at 95% power and 5% level of significance.
Recruitment
Potential participants may be identified through the EMBARC and BRONCH-UK registries at each of the participating sites, through referrals or while in clinics. Twitter and Facebook accounts (https://twitter.com/TrialCLEAR; https://www.facebook.com/TrialCLEAR/) are being used to encourage engagement and awareness of the trial. The study team will have regular teleconferences with sites to review screening and recruitment figures and resolve any issues.
Randomisation and Blinding
Treatment allocation at each site will be assigned using a concealed automated randomisation process provided by an external organisation. Participants who give their consent will be allocated using a fixed block size to one of the four groups (three intervention groups or one standard care group) in a 1:1:1:1 ratio using a central randomisation system. Randomisation will be stratified by 1) site, 2) exacerbations in the last year (2-3 times, >3 times) (to minimise baseline imbalances in antibiotic use) and 3) current use of macrolides (yes, no). The trial is open label, and patients, investigators and outcome assessors will be aware of treatment allocation.
Data Collection, Quality and Procedures
All data collected during study visits and telephone calls with each patient will be recorded in the CLEAR source documents/electronic case report form (CRF). If a participant withdraws during their first year on the study, they will be asked to attend follow-up visits for collection of outcome data. If they do not wish to attend outcome data collection, permission will be sought to access medical notes for collection of data relevant to the trial e.g. the use of antibiotics. If a participant withdraws from all parts of the study, their anonymised data (recorded up to the point of withdrawal) will be included in the study analysis. All patient data will be anonymised.
Data Management
Trial data will be entered onto the electronic CRF on a Clinical Trial Database (MACRO) by delegated site personnel and processed electronically as per the Northern Ireland Clinical Trial Unit’s (NICTU) Standard Operating Procedures (SOPs) and the study specific Data Management Plan (DMP). Data queries will be ‘raised’ electronically using MACRO where clarification from site staff is required for data validations or missing data. Site staff will respond electronically to data queries, ensuring that necessary amendments are made to the Clinical Trial Database.
Statistical analysis
Baseline characteristics, follow-up measurements and safety data will be described using descriptive summary measures depending on the scale of measurement. The primary analysis will be conducted on a modified intention to treat basis consisting of randomised participants with data from at least one post-baseline efficacy assessment. A per-protocol analysis may also be conducted to compare treatment groups. Groups will be compared for the primary outcome (number of exacerbations over 52 weeks) and antibiotic use (number of days of antibiotic use over 52 weeks) using Negative Binomial regression adjusted for baseline characteristics and other covariates. Groups will be compared for QoL-B and other continuous outcomes using analysis of covariance (ANCOVA) adjusting for baseline characteristics and other covariates. The trial’s 2.2 factorial design permits the separate testing of the effects of HTS and carbocisteine on HRQoL and the detection of any interaction between them. These tests will be implemented using three contrasts (representing HTS, carbocisteine, and the interaction) in the models. For time to next exacerbation, Kaplan-Meier curves will be prepared and the log-rank test calculated to compare the groups. Analyses will be two-sided and tested at an a priori significance level of p=0.05. The primary time point has been defined as 52 weeks from randomisation. There is no adjustment for multiple testing at the different time points, because the primary outcome has been pre-defined and prioritised. Standard approaches will be used to detect missing data.
Health economics evaluation
A within-trial economic evaluation will assess the cost-effectiveness of the four treatment options at 26 and 52 weeks from the perspective of the NHS and Personal Social Services. A within-the-table analysis will be performed, treating the four groups in the factorial design as mutually exclusive treatments. Economic outcomes will then be estimated and presented separately for each treatment option so that the effect of any interactions can be seen directly. We will estimate the cost per QALY gained, the cost per exacerbations avoided and the net benefit (NB) for each of the treatment groups. Regression analysis with an interaction term will be performed, as a robustness-check and to control for baseline covariates. Participants’ health service use and prescriptions (both related and unrelated to their BE) will be prospectively collected from baseline to 52 weeks using logs and questionnaires administered as per Table 2. Costs will be calculated by attaching appropriate unit costs from national sources. QALYs will be calculated using responses on the EQ-5D-5L over the study period. Uncertainty surrounding the incremental cost-effectiveness ratios will be summarised in cost-effectiveness acceptability curves showing the probability of the therapeutic strategies being cost-effective at different threshold levels of willingness-to-pay per QALY and per exacerbation avoided. Sensitivity analysis will be performed to explore the impact on cost effectiveness of variations in key parameters. Detailed statistical and health economic analysis plans will be finalised before the commencement of analysis.
Monitoring arrangements
On-site monitoring will be done in accordance with the trial monitoring plan. This will be an on-going activity from the time of initiation until trial close-out and will comply with the principles of Good Clinical Practice (GCP) and applicable regulatory requirements. The Data Monitoring and Ethics Committee (DMEC) will safeguard the rights, safety and wellbeing of trial participants, monitor data and make recommendations to the Trial Steering Committee (TSC) on whether there are ethical or safety reasons why the trial should not continue. They will monitor the overall conduct of the study to ensure the validity and integrity of the study findings, and will meet annually. The DMEC will comprise independent members with at least one statistician and two respiratory specialists. A DMEC charter will detail the terms of reference of the DMEC, including membership and roles and responsibilities.
Adverse Events
All directly observed adverse events (AEs) and spontaneously reported by the patient will be recorded on their CRF. Signs and symptoms of pulmonary exacerbations collected as outcomes of the trial will not be reported as AEs. Therefore, if a patient requires hospitalisation or prolongation of existing hospitalisation as a result of an exacerbation, this will not be reported as a serious adverse event (SAE). The Principal Investigator or designee will assess severity, seriousness, causality, severity and expectedness for each AE will be reported in keeping with regulatory requirements.
End of study
The main trial analysis will be conducted at 52 weeks however the formal end of the study will be at the end of the 104 week follow-up to establish mucoactive use in participants. The trial will be stopped prematurely if mandated by the responsible Research Ethics Committee (REC), Medicine and Healthcare Products Regulatory Agency (MHRA), Sponsor (e.g. following advice from the TSC based on recommendations from the DMEC) or if funding for the trial ceases. The REC that originally gave a favourable opinion of the trial and the MHRA who issued the Clinical Trial Authorisation (CTA) will be notified in writing once CLEAR has been concluded or if it is terminated early.
Site training
All sites will undertake comprehensive site initiation visits (SIV). PARI or the research team will provide training to sites on the eFlow nebuliser system with eTrack controller, SpiroSensePro and mySpiroSense spirometer. Follow-up refresher training will be delivered prior to the first patient’s first visit, and sites will be advised to send questions to the research team at any time. A frequently asked questions’ document will be maintained and circulated to sites, along with a regular newsletter detailing any updates and news regarding the trial, such as recruitment milestones.
Trial Management Arrangements
Trial specific oversight committees will be convened for CLEAR. These will include a Trial Management Group (TMG), TSC and DMEC. The NICTU will facilitate the setting-up and the co-ordination of these committees. All study amendments will be managed by the NICTU and communicated appropriately.
Patient and Public Involvement
Service users are involved in CLEAR in both a consultative and collaborative capacity and influenced this protocol, including the choice of interventions and outcomes to measure. The Chair of Primary Ciliary Dyskinesia Family Support Group UK and a BE carer is a co-applicant on the trial’s grant and a member of the TSC. The study is registered with the INVOLVE open-access database which registers research healthcare projects involving members of the public as partners in the research process.
Data Sharing and Data Access:
Requests for data sharing will be reviewed on an individual basis by the Chief Investigator (CI) and TMG. Following the publication of the trial’s main outcomes, there may be scope to conduct additional analyses on the data collected. In such instances, formal requests for data will be made to the CI for discussion with the TMG. If publications might arise from such analyses, those responsible will provide the CI with a copy of the intended manuscript for approval prior to submission to a journal.