Per NTM treatment guidelines and FDA recommendation, Arikayce is only recommended in the case of refractory disease. Refractory/stubborn NTM is defined as lack of sputum conversion after at least 6 months on standard treatment (Big 3). I just started on Arikayce after 10 months of standard treatment (with only one month negative). On the plus side, my cavity did shrink by almost 50% after 7 months of 3 x week Big 3 treatment.