CFTR modulator trial in infants paves the way for earlier access: Australian expert

Cystic fibrosis

By Nicola Garrett

24 Jul 2022

A trial in children under two years of age with cystic fibrosis will pave the way to earlier access to CFTR modulation and maybe to modifying the course of disease for up to 50% of very young children with CF, an Australian expert says.

Results from a phase III open-label trial supports the use of lumacaftor/ivacaftor in infants with cystic fibrosis homozygous for F508del-CFTR though the Queensland CF specialist Professor Claire Wainwright cautions that the risks of treatment in this age group are not completely clear.

The open-label trial by Canadian researchers included 14 children aged between 12 and 24 months with CF homozygous for F508del. Part A of the trial determined pharmacokinetics over 15 days of treatment based on weight in two age cohorts studied sequentially, first in children aged 18-24 months and then in children aged 12-18 months. Part B of the trial (n=46) assessed safety and tolerability based on adverse event reporting. 

Results showed that the pharmacokinetic profile was consistent with studies in older children. At week 24 the authors observed a sweat chloride improvement of -29.10 mmol/L, a finding that they said was consistent with improvements seen in children aged 2 to 5 years homozygous for F508del CFTR on lumacaftor/ivacaftor. There were also some ‘improving trends’ in faecal elastase-1, immunoreactive trypsinogen and faecal calprotectin. 

Overall, 44 children (95.7%) had an adverse event which were either mild (52.2%) or moderate (39.1%) in severity. The most common adverse events were cough, infective pulmonary exacerbation of cystic fibrosis, pyrexia, and vomiting. 

In an editorial accompanying the trial Professor Wainwright, Professor of Paediatrics and Child Health, University of Queensland said the trial would “pave the way” for earlier access to CFTR modulation.

However, she noted that trial designs for infants remained challenging as clinical benefits and potential harms might take time to determine and outcome measures were less well established. 

“The pace of change is now accelerating …  as more [CFTR] drugs are added with potentially greater clinical benefits, risks also increase of unrecognised adverse effects on a developing child, and will that be adequately measured in small open label trials?” she asked. 

“As CFTR modulation becomes established clinically, the window for randomised placebo-controlled trials that provide the best quality evidence has almost closed. Consumers, clinicians and researchers need to rapidly determine how we move forward in developing new CFTR modulator therapy for infants and decide whether infants are indeed “little adults” and benefits can effectively be inferred or whether they deserve the same degree of evidence that older people expect?” she asked.

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