Title: Adverse events in patients treated for Non-tuberculous mycobacteria pulmonary disease: a retrospective observational cohort study

<bold>Background:</bold> Treatment for Non-tuberculous mycobacteria pulmonary disease (NTM-PD) lasts almost 12 months. Few data are available about frequency of adverse events in course of treatment. <bold>Aims:</bold> To analyze the frequency of adverse events side effects that occurred during treatment of NTM-PD. <bold>Methods:</bold> Between 2016 and 2023, 131 patients on treatment, who came observation at INMI L. Spallanzani for NTM-PD were enrolled. <bold>Results:</bold> Mean age was 64 years, females were 73 (55%); 101 (77%) patients were reported to have M. Avium Complex, 8 (6%) M.abscessus spp; 8 (6%) M.xenopii, 6 (4.5%) M. kansasii, 4 (3%) M. scrofolaceum, 2 (1.5%) M. fortuitum, 1 (0.7%) M. peregrinum, 1 (0.7%) M. malmoense. One hundred patients (76%) developed one or more adverse effects to the therapy. 53 patients (40%) dyspepsia, 14 (11%) worsening of renal function; 18 (14%) increase in transaminases, 18 (14%) erythematous skin manifestations, 19 (15%) auditory disorders, 8 (6%) anemia, 14 (11%) leukopenia, 12 (9%) thrombocytopenia, 19 (15%) visual disturbances, 9 (7%) with documented damage to the optic nerve, 3 (2%) with peripheral neuropathy, 2 (1%) increase in QTc, 11 (8%) diarrhoea. 12 patients (9%) treatment interrupted for AE. Favourable treatment outcome was observed in 98 (75%) patients, without significant distinction of NTM species, treatment failure occurred in 6 cases (4.5%). <bold>Conclusions:</bold> Our data demonstrate that, despite the high frequency of adverse drug reactions and long-term therapy, the clinical management of NTM-PD patients in a referral center, may be successful.