PET-CT-guided versus CT-guided biopsy in suspected malignant pleural thickening: a randomised trial.

BACKGROUND: Pleural biopsy is the gold standard for diagnosis of pleural malignancy but a significant proportion will have an inconclusive biopsy despite ongoing clinical suspicion of malignancy. We investigated whether positron emission tomography-computed tomography (PET-CT) targeted pleural biopsy is superior to standard CT-guided pleural biopsy following an initial non-diagnostic biopsy. METHODS: The TARGET trial was a multicentre, parallel group randomised trial. Patients with a previous inconclusive pleural biopsy but an ongoing suspicion of pleural malignancy were randomised (1:1) to receive either CT-guided biopsy (standard care) or PET-CT followed by a targeted CT biopsy (intervention). The primary outcome was pleural malignancy correctly identified from the trial biopsy. RESULTS: Between September 2015 and September 2018, 59 participants were randomised from eight UK hospital sites: 29 to CT-only followed by targeted biopsy and 30 to PET-CT followed by targeted biopsy. The proportion of pleural malignancy correctly identified was similar between the groups (risk ratio 1.03 (95% CI 0.83-1.29); p=0.77). The sensitivity of the trial biopsy to identify pleural malignancy was 79% (95% CI 54-94%) in the CT-only group versus 81% (95% CI 54-96%) in the PET-CT group. CONCLUSIONS: The results do not support the practice of PET-CT to guide pleural biopsies in patients with a previous non-diagnostic biopsy. The diagnostic sensitivity in the CT-only group was higher than anticipated and supports the practice of repeating a CT-guided biopsy following an inconclusive result if clinical suspicion of malignancy persists.

Reflecting real-world patients with mesothelioma in research: an interim report of baseline characteristics from the ASSESS-meso cohort.

Objective: Mesothelioma varies in clinical phenotype and survival. Clinical trials are unavoidably affected by selection bias, reducing generalisability. ASSESS-meso is a UK, multicentre, prospective, mesothelioma cohort study (ISRCTN61861764). This pre-specified interim analysis, conducted when recruitment reached 25% of target, summarised participant characteristics and evaluated external validity through comparison with real-world and clinical trial cohorts. Methods: The study took place at 14 hospitals across the UK. People diagnosed with mesothelioma, at any anatomical site, were eligible. Clinical, radiological and biochemical data were collected at enrolment. In this interim report, the external validity of the cohort was investigated through comparison of baseline demographic data with populations included in the 2020 UK National Mesothelioma Audit (real-world cohort), and CHECKMATE-743 and MAPS trials (clinical trial cohorts). Results: 244 patients were enrolled between 7 April 2017 and 1 March 2022. The cohort was predominantly male (195 out of 244; 80%) with a median age of 74 years. Pleural disease and epithelioid subtypes were most prevalent. ASSESS-meso participants were more similar to the real-world population with regard to age, performance status, disease site and stage than the clinical trial population. ASSESS-meso participants were more likely to be formally staged and less likely to have undifferentiated histology compared with the real-world cohort, possibly reflecting high rates of discussion of ASSESS-meso participants at regional mesothelioma multidisciplinary team meetings. As expected, poorer performance status, non-epithelioid histology and neutrophil-lymphocyte ratio were associated with shorter survival in the adjusted analysis. Conclusion: ASSESS-meso is representative of the UK mesothelioma population. Future outputs from the cohort will help characterise different mesothelioma phenotypes with high external validity.

Protocol for a prospective observational cohort study collecting data on demographics, symptoms and biomarkers in people with mesothelioma (ASSESS-meso).

INTRODUCTION: Mesothelioma is a heterogeneous disease that can be challenging to monitor and prognosticate. ASSESS-meso is a multicentre, prospective, longitudinal observational cohort study of patients with mesothelioma. The primary aim is to describe different clinical phenotypes and investigate predictive and prognostic factors, including biomarkers from blood and pleural fluid. The secondary aim is to provide a resource for future trials and substudies. METHODS AND ANALYSIS: We aim to recruit 700 patients with a histological, cytological or clinicopathological diagnosis of mesothelioma, at any anatomical site (pleural, peritoneal, pericardial, etc). Longitudinal data will be collected, including clinical information, radiological investigations, blood tests and patient-reported outcome measures for breathlessness, chest pain and sweats. Preplanned analyses will use Cox proportional hazards method to evaluate factors associated with survival, linear and logistic regression models to investigate associations with symptoms, and analysis of variance modelling to explore changes in symptoms over time. ETHICS AND DISSEMINATION: Ethical approval has been granted by the Research Ethics Committee South West-Central Bristol (17-SW-0019) and Health Research Authority (IRAS ID 220360). A study steering committee has been established and results will be published OpenAccess in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ISRCTN: 61861764.

A trial of intra-pleural bacterial immunotherapy in malignant pleural mesothelioma (TILT) - a randomised feasibility study using the trial within a cohort (TwiC) methodology.

BACKGROUND: Malignant pleural mesothelioma (MPM) is an aggressive thoracic malignancy with a poor prognosis. Systemic immunotherapy is an effective frontline treatment for MPM, and there is a scientific rationale supporting the possible efficacy of local, i.e. intra-pleural immune modulators. Trial of intra-pleural bacterial immunotherapy (TILT) investigated the feasibility of performing a randomised trial of intra-pleural bacterial immunotherapy in people with MPM, using the trials within cohorts (TwiC) methodology. METHODS: TILT was a multicentre, three-armed, randomised, feasibility TwiC of intra-pleural OK432, BCG, or usual care in people with MPM. Eligible participants were identified from within the ASSESS-meso study, a prospective, longitudinal, observational cohort study, and were randomly selected to be offered a single dose of OK432 or BCG, via an indwelling pleural catheter. The primary outcome was feasibility, evaluated against prespecified recruitment, attrition and data completeness targets. The acceptability of trial processes and interventions was assessed during qualitative interviews with participants and family members at the end of the trial. TILT was registered prospectively on the European Clinical Trials Registry (EudraCT number 2016-004,727-23) and the ISRCTN Register on 04 December 2017. RESULTS: Seven participants were randomised from a planned sample size of 12; thus, the 66% recruitment rate target was not met. Two participants withdrew after randomisation, breaching the pre-stated attrition threshold of 10%. It was not possible to maintain blinding of control participants, which negated a fundamental tenet of the TwiC design. The trial processes and methodology were generally acceptable to participants and relatives, despite several recipients of intra-pleural bacterial agents experiencing significant local and systemic inflammatory responses. CONCLUSION: It was possible to design a clinical trial of an investigational medicinal product based on the TwiC design and to obtain the necessary regulatory approvals. However, whilst acceptable to participants and relatives, the TwiC design was not a feasible method of investigating intra-pleural bacterial immunotherapy in people with MPM. Future trials investigating this topic should consider the eligibility constraints and recruitment difficulties encountered. TRIAL REGISTRATION: TILT was registered prospectively on the European Clinical Trials Registry (EudraCT number 2016-004727-23 ) and the ISRCTN Register ( 10432197 ) on 04 December 2017.

Lymphocyte predominance in blood, pleural fluid, and tumour stroma; a prognostic marker in pleural mesothelioma.

BACKGROUND: As promising novel treatments develop for malignant pleural mesothelioma (MPM), early prognostication has become increasingly important. Circulating and local inflammatory cells are known to play a significant role in other tumour types. We assessed the proportion of lymphocyte populations within blood, pleural fluid and tumour stroma to prognosticate patients with MPM at diagnosis. METHODS: Consecutive patients diagnosed with biopsy-proven MPM were prospectively recruited to an observational cohort study and followed up for a minimum of 7.5 years. Blood and pleural fluid results at presentation were extracted from the medical records. Biopsy specimens were independently reviewed by 2 pathologists who scored the degree of lymphocytic and neutrophilic infiltration. RESULTS: Baseline results were available for 184 patients. The predominant pleural fluid cell type was calculable for 84 patients and 118 patients had biopsy specimens available for review. A low blood neutrophil/lymphocyte ratio (NLR < 4) inferred a better prognosis with a median survival of 420 days versus 301 days (p < 0.01). Survival was better for patients with a lymphocyte-predominant pleural effusion (430 vs 306 days, p < 0.01). Lymphocyte infiltration of tumour stroma was also associated with improved survival (n = 92, survival 430 days) compared with neutrophilic or acellular samples (n = 26, survival 342 days p < 0.01). In multivariable modelling lymphocyte predominance in blood, pleural fluid and tumour stroma were all associated with a better prognosis. CONCLUSIONS: Lymphocyte predominance within tumour stroma, pleural fluid or blood infers a better prognosis in patients with MPM.

The priorities of people with mesothelioma and their carers: A qualitative interview study of trial participation and treatment decisions.

PURPOSE: Treatment options for mesothelioma are increasing, as are the number of clinical trials available to patients. However, little is known about patients' and relatives' priorities when making decisions about treatment and trial participation. The aim of this study was to provide insight into people's experiences of participating in clinical research and explore the factors influencing decision-making. METHODS: Face to face, semi-structured interviews were undertaken with mesothelioma patients who were participating in the TILT trial (a randomised trial of intra-pleural immunotherapy) and their relatives. Interviews were audio-recorded, transcribed and analysed thematically. RESULTS: Twelve people were interviewed, comprising five mesothelioma patients and seven relatives. Four themes were identified relating to the experience of mesothelioma: physicality, quality of life, uncertainty and risk, and planning for an unpredictable future. A further theme related to attitudes to research participation. PARTICIPANTS: valued physical strength and were careful not to jeopardise this with potential side effects of medication. Quality of life was important and was often prioritised over survival. Participants found ambiguity challenging and sought certainty, potentially in response to the uncertainty surrounding their future. The desire for certainty impacted on risk perception; an important factor in decision-making. Relatives often advocated on behalf of patients and were more reluctant about research participation due to concern about potential risks. CONCLUSION: The study confirmed previous qualitative findings around physicality, stoicism and uncertainty, building on these themes to highlight their influence on decision-making. Important findings for practice include the challenges associated with risk communication and the differing care needs and attitudes to research of relatives.

Is Systemic Anticancer Therapy Associated With Higher Rates of Malignant Pleural Effusion Control in People With Pharmacologically Sensitive Tumors?: A Retrospective Analysis of Prospectively Collected Data.

BACKGROUND: Malignant pleural effusions (MPEs) often cause symptoms, and guidelines recommend early definitive intervention. However, observational data suggest that systemic anticancer treatment (SACT) may control MPE caused by certain pharmacologically sensitive tumors. RESEARCH QUESTION: Is SACT associated with higher rates of MPE resolution in people with pharmacologically sensitive tumors? STUDY DESIGN AND METHODS: This was a retrospective analysis of prospectively collected data from an observational cohort study of people diagnosed with MPE from lung, breast, ovarian, and hematologic malignancy between May 11, 2008, and August 6, 2017. MPE resolution (defined as radiologic resolution with removal of drain or catheter and cessation of interventions) was compared in pharmacologically sensitive (high-grade lymphoma, small cell or target-mutation-positive lung cancer, and hormone-receptor-positive breast or ovarian cancer) and nonsensitive (remainder of cohort) tumors, with and without SACT. Secondary outcomes included time to resolution, 3-month resolution rates, and total pleural interventions. RESULTS: Of 280 patients, 127 had sensitive and 153 had nonsensitive tumors. One hundred seventy-one received SACT, and 109 did not. More patients with sensitive tumors achieved MPE resolution than those with nonsensitive tumors (53/127 [41.7%] vs 42/153 [27.5%]; P = .01), and this occurred predominantly after receipt of SACT. However, hematologic malignancies were overrepresented in the sensitive group, with high rates of SACT use and MPE resolution. After adjustment for this and other confounders, no relationship was found among pharmacologic sensitivity, SACT, and MPE resolution (adjusted OR, 1.4; 95% CI, 0.5-4.1). The strongest predictor of MPE resolution was administration of chemical pleurodesis (adjusted OR, 6.2; 95% CI, 3.3-11.7). In sensitive tumors, MPE resolution occurred without chemical pleurodesis in 14 of 52 patients (26.9%; 95% CI, 15.6%-41.1%) after SACT and in 5 of 22 patients (22.7%; 95% CI, 8.2%-47.2%) without SACT. INTERPRETATION: In this observational study, SACT was not associated independently on MPE resolution in pharmacologically sensitive tumors. Randomized trials are required, but with current data, patients with symptomatic MPE should receive early definitive pleural intervention regardless of underlying tumor or intended treatment.

Standards of care in mesothelioma treatment.

The UK has the highest incidence of mesothelioma in the world, but services vary across the country partly due to uneven geographical distribution of cases. The Mesothelioma UK-funded national organisational audit has highlighted challenges in accessing diagnostic procedures such as thoracoscopy, as well as identifying examples of best practice, including access to clinical trials and specialist therapeutic procedures. To ensure equitable and optimal patient care, cancer alliances should have established referral pathways to specialist multidisciplinary team (MDT) services for discussion of all mesothelioma patients.

The Prevalence and Clinical Relevance of Nonexpandable Lung in Malignant Pleural Mesothelioma. A Prospective, Single-Center Cohort Study of 229 Patients.

Rationale: Nonexpandable lung is a recognized phenomenon that can create management challenges in patients with mesothelioma. Its prevalence and clinical importance are unknown.Objectives: The aim of this study was to describe the prevalence of nonexpandable lung and to evaluate whether there was any association between nonexpandable lung and survival in a clinical cohort of patients with mesothelioma.Methods: This was a prospective, observational cohort study of patients with mesothelioma who were seen in a single center between March 1, 2008, and August 3, 2017. Baseline characteristics were collected at diagnosis. Serial chest radiographs were assessed for the presence of pleural effusions and nonexpandable lung (defined as a lack of lung expansion after pleural aspiration or drainage). Patients were followed until they died or were censored on March 14, 2019.Results: Of 229 patients, 192 (82.7%) had a pleural effusion at presentation, and nonexpandable lung was observed in 64 of these 192 patients (33.3%). Breathlessness and cough were more frequent in patients with pleural effusions, especially in those with underlying nonexpandable lung, whereas chest pain was more prevalent in patients without effusions. Patients with pleural effusions, both with and without underlying nonexpandable lung, were more likely to have epithelioid or early-stage disease and to receive chemotherapy than patients with no pleural effusion. Nonexpandable lung was an independent risk factor for short survival, with a hazard ratio for mortality of 1.80 (95% confidence interval, 1.16-2.80) compared with patients without nonexpandable lung. The presence of a pleural effusion did not appear to be associated with a worse prognosis compared with patients with an effusion (adjusted hazard ratio, 1.86; 95% confidence interval, 0.93-3.72).Conclusions: This is the first study to describe the prevalence and clinical implications of nonexpandable lung in mesothelioma. It demonstrates that nonexpandable lung is a relatively common phenomenon that is associated with significant symptomatology and shorter survival.Keywords: mesothelioma; nonexpandable lung; pleural effusion.

Is pleural infection associated with longer survival in mesothelioma? A population-based cohort study using data from Hospital Episode Statistics.

BACKGROUND: Historically pleural infection was thought to be associated with longer survival in thoracic malignancies. The aim of this population-based cohort study was to investigate this hypothesis in mesothelioma, using national data from a high incidence country. METHODS: Case records for all patients with mesothelioma seen in English hospitals between 01/01/2005 and 31/12/2014 were extracted from Hospital Episode Statistics using International Classification of Diseases Tenth Edition (ICD-10) codes. Episodes of pleural infection were identified. Linked mortality data was obtained from the Office of National Statistics. The primary outcome was all-cause mortality. The explanatory variable was pleural infection. Cox proportional hazards model was used to analyse survival, with pleural infection, chemotherapy and thoracic surgery handled as time-variable co-factors. RESULTS: Of 22,215 patients with mesothelioma, 512 (2.3%) developed pleural infection at some point in their illness. Overall median survival was 7.0 months (IQR 2.3-16.4). Pleural infection was associated with shorter survival in the immediate post-infection period (up to 30 days - HR 1.81, 95% CI 1.45-2.22) and longer term (>30 days - HR 1.81, 95% CI 1.63-1.99). Other factors associated with increased mortality were age, male gender and being diagnosed as an inpatient. Receiving chemotherapy and being less economically deprived were associated with longer survival. CONCLUSION: Pleural infection occurred in 2.3% of people with mesothelioma and was associated with shorter survival. This refutes previous reports suggesting pleural infection may be associated with better outcomes in thoracic malignancy.

ERS/EACTS statement on the management of malignant pleural effusions.

Malignant pleural effusions (MPE) are a common pathology, treated by respiratory physicians and thoracic surgeons alike. In recent years, several well-designed randomized clinical trials have been published that have changed the landscape of MPE management. The European Respiratory Society (ERS) and the European Association for Cardio-Thoracic Surgery (EACTS) established a multidisciplinary collaboration of clinicians with expertise in the management of MPE with the aim of producing a comprehensive review of the scientific literature. Six areas of interest were identified, including the optimum management of symptomatic MPE, management of trapped lung in MPE, management of loculated MPE, prognostic factors in MPE, whether there is a role for oncological therapies prior to intervention for MPE and whether a histological diagnosis is always required in MPE. The literature revealed that talc pleurodesis and indwelling pleural catheters effectively manage the symptoms of MPE. There was limited evidence regarding the management of trapped lung or loculated MPE. The LENT score was identified as a validated tool for predicting survival in MPE, with Brims' prognostic score demonstrating utility in mesothelioma prognostication. There was no evidence to support the use of oncological therapies as an alternative to MPE drainage, and the literature supported the use of tissue biopsy as the gold standard for diagnosis and treatment planning.Management options for malignant pleural effusions have advanced over the past decade, with high-quality randomized trial evidence informing practice in many areas. However, uncertainties remain and further research is required http://ow.ly/rNt730jOxOS.

Current treatments and trials in malignant pleural mesothelioma.

OBJECTIVES: This article aims to review the evidence from recent clinical trials in mesothelioma, and to provide an overview of relevant clinical trials that are currently in progress. DATA SOURCE: Ovid MEDLINE, 1946 to present. STUDY SELECTION: Clinical trials of therapeutic interventions were considered for inclusion, regardless of phase. Of 258 papers identified in the literature search, 88 were potentially eligible based on abstract screening. Following evaluation of full-text articles, 35 were selected for inclusion in the review. RESULTS: Since the original trial that demonstrated the efficacy of pemetrexed and cisplatin in mesothelioma, multiple trials have been conducted that have further informed management options. Anti-angiogenesis agents such as bevacizumab and nintedanib appear promising as adjuncts to first-line chemotherapy. Meanwhile, immunotherapy, anti-mesothelin agents and molecular targeted therapies are potential areas for development, with ongoing trials promising to deliver interesting results over the next few years. Current evidence does not support surgical intervention; however, investigations are ongoing as to the role of extended pleurectomy/decortication, and surgery in the context of trapped lung. Finally radiotherapy is effective as a palliative measure for pain control, but is not indicated prophylactically to prevent the development of procedure tract metastases. CONCLUSION: A large amount of high-quality mesothelioma research has been conducted in the past decade. As a result, several new therapies are likely to become available in clinical practice in the near future. With multiple trials ongoing, the horizon for patients with mesothelioma looks brighter than ever before.

Are intra-pleural bacterial products associated with longer survival in adults with malignant pleural effusions? A systematic review.

BACKGROUND: Intra-pleural bacteria are effective pleurodesis agents in malignant pleural effusions. However, their relationship with survival is unclear. OBJECTIVES: We undertook a comprehensive, structured evaluation of survival outcomes in adults with malignant pleural effusions treated with intra-pleural bacterial products. DATA SOURCES: Medline, Embase, Cochrane library, Clinical Trials Registers and Open Grey. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS: Randomised controlled trials and non-randomised comparative studies were included, if the population included adults with malignant pleural effusions. Interventions of interest were any intra-pleural bacterial product, compared with placebo, alternative intra-pleural drug, or no treatment. Survival outcomes were collected. STUDY APPRAISAL AND SYNTHESIS METHODS: Two reviewers independently screened studies for eligibility, assessed papers for risk of bias and extracted data. Narrative synthesis was performed as high heterogeneity between studies precluded meta-analysis. RESULTS: 631 studies were identified, of which 14 were included. All were at high or unclear risk of bias in at least one domain. Six studies reported a survival benefit associated with intra-pleural bacterial products, whilst 8 reported no difference. Non-randomised studies and studies published prior to 2000 were more likely to report survival benefits. LIMITATIONS: There was high heterogeneity between studies, which limited the generalisability of findings. Publication bias may have affected the review as five full-text papers were unobtainable, and survival outcomes were missing in a further five. CONCLUSIONS: There is a lack of high quality evidence regarding the relationship between intra-pleural bacterial products and survival. Implications of key findings: Well-designed, prospective randomised trials are needed, to determine whether intra-pleural bacterial products can improve survival in pleural malignancy. PROSPERO REGISTRATION NUMBER: CRD42017058067.

Recurrence rates in primary spontaneous pneumothorax: a systematic review and meta-analysis.

Primary spontaneous pneumothorax (PSP) recurrence rates vary widely in the published literature, with limited data describing the factors that influence recurrence. The aims of this systematic review were to determine an estimation of PSP recurrence rates and describe risk factors for recurrence.A systematic review was conducted of all studies reporting PSP recurrence. Electronic searches were performed to identify English language publications of randomised trials and observational studies. The population was adults with PSP, who underwent conservative management, pleural aspiration or chest drainage. The outcome of interest was recurrence. Articles were screened and data extracted from eligible studies by two reviewers.Of 3607 identified studies, 29 were eligible for inclusion, comprising 13 548 patients. Pooled 1-year and overall recurrence rates were 29.0% (95% CI 20.9-37.0%) and 32.1% (95% CI 27.0-37.2%), respectively. Female sex was associated with increased recurrence (OR 3.03, 95% CI 1.24-7.41), while smoking cessation was associated with a four-fold decrease in risk (OR 0.26, 95% CI 0.10-0.63). I2 for random effects meta-analysis was 94% (p<0.0001), reflecting high heterogeneity between studies.This systematic review demonstrates a 32% PSP recurrence rate, with greatest risk in the first year. Female sex was associated with higher risk, suggesting possible sex-specific pathophysiology.

ERS/EACTS statement on the management of malignant pleural effusions.

Malignant pleural effusions (MPE) are a common pathology, treated by respiratory physicians and thoracic surgeons alike. In recent years, several well-designed randomised clinical trials have been published that have changed the landscape of MPE management. The European Respiratory Society (ERS) and the European Association for Cardio-Thoracic Surgery (EACTS) established a multidisciplinary collaboration of clinicians with expertise in the management of MPE with the aim of producing a comprehensive review of the scientific literature.Six areas of interest were identified, including the optimum management of symptomatic MPE, management of trapped lung in MPE, management of loculated MPE, prognostic factors in MPE, whether there is a role for oncological therapies prior to intervention for MPE and whether a histological diagnosis is always required in MPE.The literature revealed that talc pleurodesis and indwelling pleural catheters effectively manage the symptoms of MPE. There was limited evidence regarding the management of trapped lung or loculated MPE. The LENT score was identified as a validated tool for predicting survival in MPE, with Brims' prognostic score demonstrating utility in mesothelioma prognostication. There was no evidence to support the use of oncological therapies as an alternative to MPE drainage, and the literature supported the use of tissue biopsy as the gold standard for diagnosis and treatment planning.

Outpatient Talc Administration by Indwelling Pleural Catheter for Malignant Effusion.

BACKGROUND: Malignant pleural effusion affects more than 750,000 persons each year across Europe and the United States. Pleurodesis with the administration of talc in hospitalized patients is the most common treatment, but indwelling pleural catheters placed for drainage offer an ambulatory alternative. We examined whether talc administered through an indwelling pleural catheter was more effective at inducing pleurodesis than the use of an indwelling pleural catheter alone. METHODS: Over a period of 4 years, we recruited patients with malignant pleural effusion at 18 centers in the United Kingdom. After the insertion of an indwelling pleural catheter, patients underwent drainage regularly on an outpatient basis. If there was no evidence of substantial lung entrapment (nonexpandable lung, in which lung expansion and pleural apposition are not possible because of visceral fibrosis or bronchial obstruction) at 10 days, patients were randomly assigned to receive either 4 g of talc slurry or placebo through the indwelling pleural catheter on an outpatient basis. Talc or placebo was administered on a single-blind basis. Follow-up lasted for 70 days. The primary outcome was successful pleurodesis at day 35 after randomization. RESULTS: The target of 154 patients undergoing randomization was reached after 584 patients were approached. At day 35, a total of 30 of 69 patients (43%) in the talc group had successful pleurodesis, as compared with 16 of 70 (23%) in the placebo group (hazard ratio, 2.20; 95% confidence interval, 1.23 to 3.92; P=0.008). No significant between-group differences in effusion size and complexity, number of inpatient days, mortality, or number of adverse events were identified. No significant excess of blockages of the indwelling pleural catheter was noted in the talc group. CONCLUSIONS: Among patients without substantial lung entrapment, the outpatient administration of talc through an indwelling pleural catheter for the treatment of malignant pleural effusion resulted in a significantly higher chance of pleurodesis at 35 days than an indwelling catheter alone, with no deleterious effects. (Funded by Becton Dickinson; EudraCT number, 2012-000599-40 .).

Commentary: considerations for using the 'Trials within Cohorts' design in a clinical trial of an investigational medicinal product.

BACKGROUND: The 'trials within cohorts' (TwiC) design is a pragmatic approach to randomised trials in which trial participants are randomly selected from an existing cohort. The design has multiple potential benefits, including the option of conducting multiple trials within the same cohort. MAIN TEXT: To date, the TwiC design methodology been used in numerous clinical settings but has never been applied to a clinical trial of an investigational medicinal product (CTIMP). We have recently secured the necessary approvals to undertake the first CTIMP using the TwiC design. In this paper, we describe some of the considerations and modifications required to ensure such a trial is compliant with Good Clinical Practice and international clinical trials regulations. We advocate using a two-stage consent process and using the consent stages to explicitly differentiate between trial participants and cohort participants who are providing control data. This distinction ensured compliance but had consequences with respect to costings, recruitment and the trial assessment schedule. CONCLUSION: We have demonstrated that it is possible to secure ethical and regulatory approval for a CTIMP TwiC. By including certain considerations at the trial design stage, we believe this pragmatic and efficient methodology could be utilised in other CTIMPs in future.