Children ages two to five who have the most common form of cystic fibrosis (CF), caused by two copies of the F508 gene mutation, have not had any modulator treatments available to them until recently. A new study authored by researchers at Children’s Hospital Colorado and published May 6, 2021, in Lancet Respiratory Medicine shows that the CFTR modulator – lumacaftor/ivacaftor – can be safe and well-tolerated for this age range for up to 120 weeks, allowing younger children to begin proactive treatment of CF earlier in their lives.