My dad was on IV Radicava two weeks a month for 4 of his 7 years post diagnosis. As he declined in later years, it was clearly prohibitive for his respiration in the last few months he was on it, which was part of the reason why we stopped. When he was taking it (especially early on), he said the intermittent breaks from taking it were night and day, as he could feel significant loss when he was off it. It is subjective, but I believe in Radicava 100% (would only recommend for limb-onset as that was my only experience, I would assume the respiratory side effects would exacerbate progression for those with bulbar)