Dupilumab for Severe Asthma in a Real Life Setting

Introduction:

Asthma is a worldwide burden affecting more than 300 millions patients. Although the vast majority of asthma patients suffer from mild to moderate diseases whose symptoms can be assessed with inhaled corticosteroids (CSI) and bronchodilators, 3.7% of them present with severe asthma (SA). SA is defined as an asthma remaining uncontrolled despite adherence with maximal optimized therapy and treatment of contributory factors, or that worsens when high dose treatment is decreased. SA represents a small proportion of patients but the very heart of the asthma problem with tremendous health costs, high morbidity and significant mortality. Thus it has been the center of therapeutic research interest for the past decade and different treatments have achieved development and reglementary approvals. Among them, dupilumab is a fully human monoclonal antibody targeting the alpha subunit of the interleukin 4 receptor, blocking both IL-4 and IL -13 pathways. It is therefore interacting with the type 2 inflammation response observed in eosinophilic asthma. The French Ministry of Health therefore opened a window of appeals for TUA from September 2017 to January 2018, allowing early access to dupilumab for SA patients demonstrating unacceptable steroids side effects and/or life-threatening exacerbations, irrespective of their T2 status. By that time indeed, phase 3 randomized clinical trials (RCT) on eosinophilic patients had not yet been published.

In this phase IV real-life study with no placebo group, the investigators aimed to describe patients' characteristics and to evaluate the efficacy and safety of Dupilumab on non-selected SA patients.

Method:

This multicenter retrospective observational real-life study was conducted at 13 public teaching hospitals across the country. All French SA patients who received dupilumab under the TUA between September 2017 and January 2018 were included in the survey, as long as they had received at least one injection and completed at least one follow-up visit in the first 12 months of treatment. No inclusion criteria were required, but patients' files had previously been screened through by health authorities and validated by Sanofi to allow dupilumab TUA. Physicians had had to certify that patients had SA with no other treatment available at that time, and that poor asthma control and/or severe steroid side effects required scaling up treatment. Patients were not required to have eosinophilia. However, patients were excluded from the TUA if they presented with previous hypereosinophilia > 1500/mm3, as symptomatic hypereosinophilia has previously been described with dupilumab in this particular population.

Investigators were free to decide on the frequency of visits, blood tests and function assessments, as to define the tools of control assessment, in adequacy with their usual practice. On line and paper questionnaires were retrospectively filled.

Main objective of the study was to describe asthma control at 12 months and secondary objectives were descriptive data of the population, efficacy, safety and tolerability of dupilumab treatment. Statistics of patients' characteristics were compiled. Efficacy was assessed in the per-protocol population, defined as all the patients who completed visits at 3, 6 and/or 12 months. Differences between baseline and follow-up visits were compared by Wilcoxon signed-rank test and rank-sum test. ACT evolution during study was assessed with a mixed linear model.

Response was eventually assessed by each investigator using the GETE score (5 categories, graded from 1 to 5, respectively defining the disease control as excellent - good - moderate - poor and worsening). Categories 1 and 2 are considered as good response.

Clinical response was defined as gain of ACT score of more than 5 points compared to previous assessment or ACT > 18. Time to first clinical response was evaluated using Kaplan-Meier curves.

Safety and tolerability were evaluated on the basis of each investigator notifications The protocol was approved by the institutional review boards of the French learned society for respiratory medicine - Société de Pneumologie de Langue Française and of the Paris University Hospitals - Assistance Publique - Hôpitaux de Paris. The independent Committee for the protection of persons (CPP) gave a favourable opinion. All patients provided oral consent to the collection of their data. As a non interventional retrospective study, no written consent was required.