Treatment outcomes and safety of clofazimine in nontuberculous mycobacterial pulmonary disease (NTM-PD)

Nontuberculous mycobacterial (NTM) infections are difficult to treat and are associated with significant morbidity and mortality. Reported success rates with guideline-based therapy vary depending on NTM species and up to 70% experience treatment related side effects. There is limited data on the safety and efficacy of clofazimine, a commonly used second line drug in the treatment of NTM pulmonary disease (NTM-PD). All patients with NTM-PD treated with clofazimine between June 2017 and June 2022 across five major metropolitan hospitals were analysed to determine the success rates of clofazimine containing regimens and associated adverse events, in the treatment of NTM-PD. A total of 157 patients were included in the analysis. Clofazimine was used as first line therapy in 93 patients (59%), substitution therapy in 29 patients (19%) and as add-on therapy in 35 patients (22%). Of the 147 patients with a treatment outcome recorded, 88 patients (56%) had successful treatment outcomes (61% [65/106] with Mycobacterium avium complex; 56% [19/34] of patients with M. abscessus infection). Success was more likely when clofazimine was used in a first line treatment regimen (62%) or as a substitute treatment (68%) than as salvage therapy (47%). Adverse events were reported in 50% (79/157) of patients, mostly dermatological (41/157, 26%) and gastrointestinal (36/157, 23%). 21 patients (13%) discontinued clofazimine due to an adverse event. The inclusion of clofazimine in treatment regimens for NTM-PD resulted in comparable outcomes and a favourable safety profile when compared with other first line therapy.