[Not Available].

Most published applications of the estimand framework have focused on superiority trials. However, non-inferiority trials present specific challenges compared to superiority trials. The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use notes in their addendum on estimands and sensitivity analysis in clinical trials that there may be special considerations to the implementation of estimands in clinical trials with a non-inferiority objective yet provides little guidance.

Why estimands are needed to define treatment effects in clinical trials.

Background: The estimand for a clinical trial is a precise definition of the treatment effect to be estimated. Traditionally, estimates of treatment effects are based on either an ITT analysis or a per-protocol analysis. However, there are important clinical questions which are not addressed by either of these analyses.

Adherence, per-protocol effects, and the estimands framework.

In the statistical literature, treatment effects in clinical trials are frequently described as either ITT or per-protocol effects. The estimand given for the per-protocol effect is the effect in adherers, where adherers are typically defined as adhering to the intervention as specified in the trial protocol. This dichotomy of treatment effects is unhelpful when there are in reality multiple treatment effects that can be of clinical interest and relevance.

Estimation of a treatment policy estimand for time to event data using data collected post discontinuation of randomised treatment.

Discontinuation from randomised treatment is a common intercurrent event in clinical trials. When the target estimand uses a treatment policy strategy to deal with this intercurrent event, data after cessation of treatment is relevant to estimate the estimand and all efforts should be made to collect such data. Missing data may nevertheless occur due to participants withdrawing from the study and assumptions regarding the values for data that are missing are required for estimation.

From DREAM to REALITI-A and beyond: Mepolizumab for the treatment of eosinophil-driven diseases.

Effective treatment of inflammatory diseases is often challenging owing to their heterogeneous pathophysiology. Understanding of the underlying disease mechanisms is improving and it is now clear that eosinophils play a complex pathophysiological role in a broad range of type 2 inflammatory diseases. Standard of care for these conditions often still includes oral corticosteroids (OCS) and/or cytotoxic immune therapies, which are associated with debilitating side effects.

Why ITT analysis is not always the answer for estimating treatment effects in clinical trials.

For many years there has been a consensus among the Clinical Research community that ITT analysis represents the correct approach for the vast majority of trials. Recent worldwide regulatory guidance for pharmaceutical industry trials has allowed discussion of alternatives to the ITT approach to analysis; different treatment effects can be considered which may be more clinically meaningful and more relevant to patients and prescribers. The key concept is of a trial "estimand", a precise description of the estimated treatment effect.

Assessing efficacy in important subgroups in confirmatory trials: An example using Bayesian dynamic borrowing.

Assessment of efficacy in important subgroups - such as those defined by sex, age, race and region - in confirmatory trials is typically performed using separate analysis of the specific subgroup. This ignores relevant information from the complementary subgroup. Bayesian dynamic borrowing uses an informative prior based on analysis of the complementary subgroup and a weak prior distribution centred on a mean of zero to construct a robust mixture prior.

Clinical Development of Mepolizumab for the Treatment of Severe Eosinophilic Asthma: On the Path to Personalized Medicine.

The development of mepolizumab, an anti-IL-5 monoclonal antibody for the treatment of severe eosinophilic asthma, is an example of a clinical development program that evolved over time based on sound, basic scientific principles. Initial clinical data on the effects of mepolizumab on lung function in a general asthmatic population were disappointing. However, it became clear that mepolizumab may be more effective against other clinical endpoints, particularly asthma exacerbations, in patients with more severe disease.

What matters most? Different stakeholder perspectives on estimands for an invented case study in COPD.

In drug development, we ask ourselves which population, endpoint and treatment comparison should be investigated. In this context, we also debate what matters most to the different stakeholders that are involved in clinical drug development, for example, patients, physicians, regulators and payers. With the publication of draft ICH E9 addendum on estimands in 2017, we now have a common framework and language to discuss such questions in an informed and transparent way.

Efficacy of add-on mepolizumab in adolescents with severe eosinophilic asthma.

Adolescents (12-17 years of age) with severe eosinophilic asthma experience frequent exacerbations and reduced lung function leading to poor health-related quality of life. Mepolizumab is approved for add-on maintenance therapy in patients with severe eosinophilic asthma ≥ 6 years of age in the EU and ≥ 12 years of age in other regions (including the USA), based on a Phase II/III program demonstrating reduced exacerbation rates with 4-weekly treatment. A total of 34 adolescent patients were recruited across the Phase III mepolizumab trials.

Disease burden and efficacy of mepolizumab in patients with severe asthma and blood eosinophil counts of ≥150-300 cells/μL.

Background: In patients with severe eosinophilic asthma, treatment decisions can be determined by blood eosinophil counts; however, a specific blood eosinophil threshold has not been defined for starting mepolizumab treatment.

Methods: We summarized the disease burden and efficacy of mepolizumab in patients with severe eosinophilic asthma and baseline blood eosinophil counts of ≥150-300 cells/μL and ≥300 cells/μL using data from the mepolizumab clinical development program (DREAM [NCT01000506], MENSA [NCT01691521], SIRIUS [NCT01691508] and MUSCA [NCT02281318]).

Results: The morbidity of asthma in patients with baseline blood eosinophil counts ≥150-300 cells/μL was similar to that in patients with blood eosinophil counts ≥300 cells/μL, with similar rates of exacerbations (2.

Strategies for composite estimands in confirmatory clinical trials: Examples from trials in nasal polyps and steroid reduction.

The draft addendum to the ICH E9 regulatory guideline asks for explicit definition of the treatment effect to be estimated in clinical trials. The draft guideline also introduces the concept of intercurrent events to describe events that occur post-randomisation that may affect efficacy assessment. Composite estimands allow incorporation of intercurrent events in the definition of the endpoint.

Asthma Exacerbations Associated with Lung Function Decline in Patients with Severe Eosinophilic Asthma.

Background: Limited data describe the association between the frequency of asthma exacerbations and the decline in lung function in severe asthma.

Objective: To determine whether asthma exacerbations are associated with enhanced decline in lung function.

Methods: Changes in lung function were analyzed retrospectively using data from the DREAM and MENSA studies of mepolizumab intervention in patients with severe asthma.

Evaluation of Potential Continuation Rules for Mepolizumab Treatment of Severe Eosinophilic Asthma.

Background: Mepolizumab significantly reduces exacerbations in patients with severe eosinophilic asthma. The early identification of patients likely to receive long-term benefit from treatment could ensure effective resource allocation.

Objective: To assess potential continuation rules for mepolizumab in addition to initiation criteria defined as 2 or more exacerbations in the previous year and blood eosinophil counts of 150 cells/μL or more at initiation or 300 cells/μL or more in the previous year.

Biomarkers for severe eosinophilic asthma.

The last decade has seen the approval of several new biologics for the treatment of severe asthma-targeting specific endotypes and phenotypes. This review will examine how evidence generated from the mepolizumab clinical development program showed that blood eosinophil counts, rather than sputum or tissue eosinophil counts, evolved as a pharmacodynamic and predictive biomarker for the efficacy of treatment with mepolizumab in patients with severe eosinophilic asthma. Based on the available evidence and combined with clinical judgement, a baseline blood eosinophil threshold of 150 cells/μL or greater or a historical blood eosinophil threshold of 300 cells/μL or greater will allow selection of patients with severe eosinophilic asthma who are most likely to achieve clinically significant reductions in the rate of exacerbations with mepolizumab treatment.

Meta-analysis of asthma-related hospitalization in mepolizumab studies of severe eosinophilic asthma.

Background: Studies show that mepolizumab can reduce the frequency of clinically significant exacerbations in patients with severe eosinophilic asthma, compared with placebo. However, important events such as hospitalizations and emergency room visits are rare and difficult to characterize in single studies.

Objective: We sought to compare hospitalization or hospitalization and/or emergency room visit rates in patients with severe eosinophilic asthma treated with mepolizumab or placebo in addition to standard of care for at least 24 weeks.

Severe eosinophilic asthma treated with mepolizumab stratified by baseline eosinophil thresholds: a secondary analysis of the DREAM and MENSA studies.

Background: Findings from previous studies showed that mepolizumab significantly reduces the rate of exacerbations in patients with severe eosinophilic asthma. To assess the relationship between baseline blood eosinophil counts and efficacy of mepolizumab we did a secondary analysis of data from two studies, stratifying patients by different baseline blood eosinophil thresholds.

Methods: We did a post-hoc analysis of data, which was completed on Sept 25, 2015, from two randomised, double-blind, placebo-controlled studies of at least 32 weeks duration (NCT01000506 [DREAM] and NCT01691521 [MENSA]) done between 2009 and 2014.

Estimands: discussion points from the PSI estimands and sensitivity expert group.

ICH E9 Statistical Principles for Clinical Trials was issued in 1998. In October 2014, an addendum to ICH E9 was proposed relating to estimands and sensitivity analyses. In preparation for the release of the addendum, Statisticians in the Pharmaceutical Industry held a 1-day expert group meeting in February 2015.

Oral glucocorticoid-sparing effect of mepolizumab in eosinophilic asthma.

Background: Many patients with severe asthma require regular treatment with oral glucocorticoids despite the use of high-dose inhaled therapy. However, the regular use of systemic glucocorticoids can result in serious and often irreversible adverse effects. Mepolizumab, a humanized monoclonal antibody that binds to and inactivates interleukin-5, has been shown to reduce asthma exacerbations in patients with severe eosinophilic asthma.