Study	Reason for exclusion
Kerem 2008	Participants not controlled, randomised or blinded to treatment.
McIntosh 2014b	Not a randomised controlled trial; participants invited to single allocation safety trial after completing a previous randomised controlled trial.
Pradal 2002	Cross‐over trial and data from first treatment arm not presented independently. Data requested, but no response to date.
Romano 2000	Controlled clinical trial: participants were not randomised or blinded to treatment. Controls stated to be participants homozygous for deltaF508 mutations.
Wilschanski 2003	Cross‐over trial in which each participant served as their own control. Reported on mechanism of action of the intervention (nasal potential difference and immunofluorescence microscopy of primary human airway cells) which were not relevant to this review which is looking at clinical benefit.