The effect of combined therapy according to the guidelines for the treatment of Mycobacterium avium complex pulmonary disease

Objective To investigate whether the combined therapy according to the guideline proposed by American Thoracic Society (ATS) and Japanese Society for Tuberculosis (JST) is clinically appropriate for Mycobacterium avium complex (MAC) pulmonary disease. Patients Seventy-one patients in whom MAC pulmonary disease was diagnosed at Kawasaki Medical School and our associated ten hospitals were prospectively studied. Results Seventy-one patients with Mycobacterium avium complex (MAC) pulmonary disease were 27 males and 44 females with a mean age of 64.4 +/- 10.2 years old. Patients received 400 mg/day or 600 mg/day of clarithromycin plus ethambutol, rifampicin, and initial streptomycin for 12 months. Among 71 patients who received more than 12 months of therapy, 41 patients (57.7%) converted their sputum to negative within six months after the initiation of this regimen, 16 of 41 patients (39.0%) relapsed, and 23 of 71 patients (32.4%) obtained clinical improvement on chest X-ray and/or clinical symptoms. The mortality rate had a comparatively good prognosis with a low incidence of 2.8%. Although the species of pathogen (M. avium or M. intracellulare) did not significantly affect the conversion rate or clinical improvement, the infectious form with or without respiratory underlying disease, the characteristics and extent of lesion on chest X-ray, and the dose of clarithromycin significantly influenced the conversion rate or clinical improvement. There were no problems concerning adverse reactions for this regimen. Conclusion This combined therapy, according to the guideline proposed by ATS and JST, was one of the effective treatments compared to the clinical effect of only antituberculous drugs through this study. However, this combined therapy was unsatisfactory compared to the clinical effect for pulmonary tuberculosis. The development of new companion drugs for MAC pulmonary diseases is needed.