@kathyjjb I don't know what you are treating, but with MAC cavitary lung disease specifically, I have not found any source that recommends treatment with only Arikayce. It is usually the Big 3 plus Arikayce. Sometimes, in the right setting, rifampin may be swapped out for clofazimine. I see that you are also resistant to all macrolides which obviously complicates matters. Of course we see lately with NB disease only, treatment may consist of azithromycin and ethambutol only. Perhaps you are looking to swap out both the azithromycin and rifampin with the Arikayce (keeping the ethambutol?). In any event, generally speaking Arikayce is not considered a stand-alone treatment for MAC. If you find different information, please share.