It seems they were looking for a specific response/improvement in CF patients that have two copies of the cystic fibrosis transmembrane conductance regulator gene, which I gather is important to what this arm of the study is all about. Perhaps it is for expanded labeling or similar.
This is their second genetic mutation/genetic therapy sequence. Remember, the original study showed that CF patients with lung infections did not respond quickly to the genetic therapy treatments of the first drug. Stands to reason. Inflammation interferes with cellular drug absorption and metabolism of drugs. Infection of the conducting airways (bronchioles) of the lungs causes inflammation. Arikace (or other inhalational or systemic antibiotic) to eliminate an airway infection would be a pretreatment to using these therapeutic genetic drugs effectively. Connect the dots.
Arikace is not competing with genetic therapys, it is facilitating them to be efficaous (effective).