Motivations and experiences of patients with respiratory disease and their caregivers in a multinational trial of mirtazapine for severe breathlessness: a qualitative study (BETTER-B).

Background: Drug repurposing offers advantages over traditional drug development, such as shorter time and reduced costs. Understanding patient and caregiver perspectives on repurposed medicines is crucial to improving clinical trial design and conduct, especially in advanced disease. We carried out this study in the UK and Italy to explore the experiences and motivations of patients with respiratory diseases and their caregivers who participated in a trial investigating the repurposing of the antidepressant mirtazapine to alleviate severe breathlessness.

Methods: Qualitative study nested within a double-blind, placebo-controlled, randomised trial (BETTER-B: BETter TreatmEnts for Refractory Breathlessness). Purposive sampling ensured diversity in age and gender. Framework analysis was applied. Interviewed participants had Chronic Obstructive Pulmonary Disease (COPD) or Interstitial Lung Disease (ILD), experienced limiting breathlessness (grade 3 or 4 of the modified Medical Research Council breathlessness scale) and had participated in the trial.

Results: Twenty-three patients (13 men and 10 women) and eight caregivers (4 men and 4 women) were interviewed. Of patients (15 COPD, 8 ILD), 22 had completed the trial and one had withdrawn due to adverse effects. Interviews were conducted at home or via the telephone. Two main themes were derived: (1) 'knowledge and views about antidepressants and its use' and (2) 'experience and views on joining the trial'. The patients' perceived need for relief from severe breathlessness and its impact outweighed any concerns about taking an antidepressant. Motivations for trial participation included the potential for benefit, altruism, trust in the healthcare system, and the strength of relationships between patients and healthcare professionals.

Conclusions: Participants willing to accept mirtazapine repurposed for another indication joined this trial regardless of their existing concerns about antidepressants. A clear explanation of trials and possible benefits, plus trust in professionals and the healthcare system, are instrumental in increasing trial participation for repurposed medicines.

Trial registration: ISRCTN Registry, ISRCTN10487976. Prospectively Registered on 19 November 2019.