Lumacaftor/ivacaftor combination therapy benefits patients with cystic fibrosis homozygous for the Phe508del CFTR mutation with moderate to severe lung dysfunction, a pooled analysis of data from the TRAFFIC and TRANSPORT studies shows.
The research team including Dr Stuart Elborn from Queens University in Belfast and Professor Claire Wainwright from the University of Queensland in Australia stratified patients from the studies by degrees of CF lung disease severity.
They found that for those with mild lung disease (ppFEV1 >70), combination therapy had a similar efficacy and safety profile to that of the overall trial population.
Patients with more severe disease (ppFEV1 <40) at the time of their baseline visit also had similar absolute changes in ppFEV1 to that seen in the overall clinical trial population.
Some improvements were also seen in the severe subgroup for secondary endpoints such as body-mass index and exacerbation frequency.
However, patients with severe lung disease also had an increased incidence of adverse events such as cough, dyspnoea and chest tightness.
These symptoms were usually of early onset and generally self-limiting, the researchers reported in the study published in The Lancet Respiratory Medicine.
Writing in an accompanying editorial Edward F McKone from St Vincent’s University Hospital in Dublin said that although the sample size was small, the study gave an important insight into the efficacy and safety of combination therapy.
“These results are important as they can help guide the initiation of lumacaftor/ivacaftor therapy in patients with more advanced cystic fibrosis,” he wrote.
These patients should be counselled about respiratory side-effects and monitored closely after initiation of treatment for a possible increase in respiratory symptoms, he advised.
The efficacy and safety of combination therapy in patients with very severe lung disease (ppFEV <30) was unknown and a prospective clinical trial was underway (NCT02390219), he added.