What is the recommended treatment for Mycobacterium Avium Complex (MAC) lung disease?

From the Guidelines

The recommended treatment for Mycobacterium Avium Complex (MAC) lung disease is a multidrug regimen consisting of a macrolide, ethambutol, and a rifamycin, with treatment duration of at least 12 months after culture conversion. For nodular/bronchiectatic disease, the standard regimen includes a macrolide (clarithromycin or azithromycin), ethambutol, and a rifamycin (rifampin or rifabutin) 1. The specific regimen may vary depending on the severity of the disease, with cavitary or severe nodular/bronchiectatic disease requiring a more intensive approach, possibly including the addition of an injectable aminoglycoside like amikacin in the initial phase 1. Some key points to consider in the treatment of MAC lung disease include:

• The use of a macrolide-based regimen, with clarithromycin or azithromycin as the primary macrolide option 1
• The importance of treatment duration, with at least 12 months of treatment after culture conversion 1
• The need for regular monitoring, including monthly sputum cultures until conversion, liver function tests, and visual acuity and color discrimination tests for patients on ethambutol 1
• The potential for side effects, such as gastrointestinal disturbances, liver toxicity, and vision changes with ethambutol, and the importance of medication adherence despite these side effects 1. Overall, the treatment of MAC lung disease requires a prolonged multidrug approach, due to the natural resistance of MAC organisms to many antibiotics and the difficulty of eradicating them without sustained combination therapy 1.

From the Research

Treatment Options for MAC Lung Disease

• The recommended treatment for Mycobacterium Avium Complex (MAC) lung disease typically involves a combination of multiple antibiotics, including a macrolide, ethambutol, and rifampin 2, 3.
• However, drug intolerances and interactions are common with the current recommended treatment, and there is limited information on outcomes with alternative medications 2.
• Studies have shown that treatment with a macrolide, ethambutol, and clofazimine can be successful in patients with MAC lung disease, and may be considered as an alternative to rifamycin-containing regimens 2, 3.
• A macrolide-containing three-drug regimen is recommended over a two-drug regimen as a standard treatment, and azithromycin is recommended rather than clarithromycin 4.
• The concomitant use of aminoglycoside, amikacin liposomal inhalation, clofazimine, linezolid, bedaquiline, and fluoroquinolone with modification of guideline-based therapy has been studied as alternative treatment options 4.

Treatment Duration and Outcomes

• The treatment duration for MAC lung disease is typically at least one year after culture conversion 4.
• Studies have shown that the majority of patients with MAC lung disease achieve negative sputum culture results, but re-treatment is needed in approximately one-third of patients 2.
• Microbiologic relapse occurred in 49% of patients in one study, and there was no difference in microbiologic relapse or re-treatment rates between patients treated with clofazimine-containing regimens and those treated with rifampin-containing regimens 2.

Adverse Events and Pharmacokinetics

• Adverse events associated with high-dose rifabutin in macrolide-containing regimens for the treatment of MAC lung disease have been reported, including a reduction in the mean total white blood cell count, gastrointestinal symptoms, and abnormal liver enzyme levels 5.
• Pharmacokinetic studies have shown that currently recommended multidrug treatment regimens for MAC lung disease yield limited cure rates, in part due to incomplete understanding of the pharmacokinetics and pharmacodynamics of the drugs 6.
• Peak serum concentrations below target range were frequent for ethambutol, clarithromycin, and azithromycin, and concurrent administration of rifampicin led to decreases in peak serum concentrations of these drugs 6.