A phase therapy regimen containing clofazimine manifested high efficacy in treating Mycobacterium abscessus pulmonary disease

BACKGROUND: The guidelines for Mycobacterium abscessus pulmonary disease do not provide a clear approach to combination therapy. This study aims to assess the effectiveness of phase therapy (PT) containing clofazimine (CFZ) for patients with Mycobacterium abscessus pulmonary disease. METHODS: This study was carried out at Beijing Chest Hospital, Capital Medical University. It included 24 confirmed cases of Mycobacterium abscessus pulmonary disease who were prospectively enrolled and treated with a CFZ-containing regimen. Additionally, 35 confirmed cases were retrospectively included for comparison. Baseline information of patients was collected. Patients were followed up for over a year. Minimal inhibitory concentration (MIC) testing was conducted on clinical isolates from patients to determine if there is a correlation between MIC values and sputum culture conversion. RESULTS: The retrospective patients achieved a 36.7% (11/30) sputum culture conversion while PT achieved a 70.8% (17/24) sputum culture conversion. Patients using the PT regimen were more likely to achieve sputum culture conversion (P = 0.013). The MIC range of CFZ of baseline isolates from 54 Mycobacterium abscessus pulmonary disease patients was 0.125 -1 mg/L. Among prospective patients, the success rate of treatment was 86.7% (13/15) for patients with CFZ MIC < 0.5 mg/L, while it was 44.4% (4/9) for those with MIC ≥ 0.5 mg/L. Prospective patients with CFZ MIC < 0.5 mg/L were more likely to achieve sputum culture conversion (P = 0.014). Logistic regression analysis showed that prospective patients who received the five-drug regimen were independently associated with sputum culture conversion [OR = 6.203, 95% CI = (1.171–32.865), P = 0.032). CONCLUSION: The PT regimen is effective against Mycobacterium abscessus pulmonary disease, particularly in cases where CFZ MIC is < 0.5 mg/L.