Finding the Optimal Regimen for Mycobacterium Abscessus Treatment

Mycobacterium abscessus (MABS) is a group of rapid-growing, multi-drug resistant non-tuberculous mycobacteria (NTM) causing infections in humans. MABS pulmonary disease (MABS-PD) can result in significant morbidity, increased healthcare utilisation, accelerated lung function decline, impaired quality of life, more challenging lung transplantation, and increased mortality. While the overall numbers affected is small, the prevalence of infections is increasing worldwide. The Finding the Optimal Regimen for Mycobacterium abscessus Treatment (FORMaT) trial aims to produce high quality evidence for the best treatment regimens to maximise health outcomes and minimise toxicity and treatment burden, as well as developing biomarkers (serology, gene expression signatures, and radiology) to guide decisions for starting treatment and measuring disease severity in patients with MABS PD.

Mycobacterium abscessus (MABS) are a group of non-tuberculous mycobacteria (NTM) found in water and soil habitats that exhibit high levels of intrinsic multi-drug resistance. They are recognised opportunistic human pathogens capable of causing chronic pulmonary disease (MABS-PD), predominantly in individuals with underlying inflammatory lung diseases.

Finding the Optimal Regimen for Mycobacterium abscessus Treatment (FORMaT) is an iterative, standing, platform trial with innovative and adaptive properties that evaluate and develop the optimal combinations of therapies for children and adults with MABS-PD to clear MABS infection with acceptable tolerance. We will use these opportunities afforded by the clinical trial platform to establish discovery studies to: (i) understand the effects of disease and treatment on health-related quality of life, (ii) determine cost effectiveness of interventions, (iii) optimise pharmacokinetic drug dosing, (iv) understand susceptibility to MABs-PD, (v) develop biomarkers of clinical disease, (vi) investigate genomics of MABs strains causing MABs-PD and development of antimicrobial resistance.

FORMaT provides a pragmatic design to address challenges to develop an evidence base for the first time for MABS-PD. Initially, the trial has been designed to test therapies that are currently the basis for treatment guidelines for MABS-PD. The trial has the capacity to add new treatments and to eliminate therapies because of futility as they either lack efficacy or cause unacceptable toxicity. Novel therapeutic approaches are then tested against the previously determined optimal approaches, thus leading in an iterative fashion to improve microbiological clearance, and health outcomes associated with MABS-PD. The trial is designed as a series of trials within the main trial to enable investigation of the different phases of treatment; intensive (intravenous treatment phase) and consolidation (oral and or inhaled treatment phase) based on clinical guidelines. The primary outcome for each trial is microbiological clearance with clinical tolerance (Grade 1 or 2) based on Common Terminology Criteria for Adverse Events (version 5). This enables subjects to continue in the trial even if tolerance is poor or they change treatments in a specific phase of the trial as those events contribute to the primary outcome determination.

Eligibility Criteria:
Intervention Cohort Inclusion Criteria:

* Subjects with respiratory cultures positive for M. abscessus (MABS) (sub species abscessus, sub species bolletii, or subspecies massiliense) are required to meet all 3 American Thoracic Society criteria (clinical, radiological and microbiological) for MABS pulmonary disease (PD).
* Subjects with mixed NTM infections (slow growers + MABS) (adding ethambutol will be permitted if required by the treating physician).
* Willingness and ability to comply with trial regimens and the study visit requirements.

Intervention cohort Exclusion Criteria:

* Receiving active treatment for MABS within the previous 12 months, except azithromycin for participants with cystic fibrosis and bronchiectasis.
* Healthy volunteers may not participate.
* Pregnancy or planning to continue breastfeeding
* Known hypersensitivity to any of the therapies for which no alternate options(s) have been provided.

Observation Cohort Inclusion Criteria:

* At least one positive respiratory MABS culture
* Willingness and ability to comply with the study visit requirements.

Observation cohort Exclusion Criteria for:

* Receiving active treatment for MABS within the previous 12 months, except azithromycin for participants with cystic fibrosis and bronchiectasis.
* Healthy volunteers may not participate.