What the Vertex Phase III Results Mean

Following yesterday's announcement from Vertex Pharmaceuticals of the results of the Phase III clinical trial of the ivacaftor and lumacaftor combination therapy, our Director of Care & Research Dr Janet Allen explains the key results.

Vertex announced the Phase III

combination clinical trial results for people with cystic fibrosis carrying two copies of F508del (which accounts for around 50% of the UK cystic fibrosis population). Now the dust has settled from the flurry of excitement, I’ve had a chance to look through some of the details in the text beyond the headline data on FEV1 lung function. What I find striking is the effect of the combination treatment on pulmonary exacerbations, which is remarkable, especially alongside such modest effects on FEV1. This finding on pulmonary exacerbations translates through to significant reductions in hospitalisations (39-61%) and IV antibiotics (45-56%). As we all know, pulmonary exacerbations contribute to continuing decline in lung function for people with cystic fibrosis. Together with the need for hospitalisations and IV antibiotics, this has a demoralising effect on individuals and their quality of life. The data here implies that these events could be halved by the combination treatment.  We have just come off the phone with Vertex where we discussed this exciting data and the team commented that many of its expert panel have also remarked on the beneficial effect on pulmonary exacerbations and how disproportionate it is to the effect on FEV1. Clearly more analysis needs to be completed and we need to have a better understanding of this effect but it is remarkable and shows that FEV1 is not necessarily the gold standard marker for measuring the effect of a drug in cystic fibrosis.

The other point that should not be missed is that this is a landmark scientific achievement. The F508del mutation in CFTR causes this protein to be fold incorrectly, which is a really difficult problem to fix. Many other conditions are caused by misfolded proteins and many programmes have tried unsuccessfully to restore the folding pathways in people. Here, a small molecule has been discovered that affects the complex folding of the protein, CFTR. This is an amazing achievement and shows the real value of linking high quality science and drug discovery with the determination to make a difference. 

The Trust is looking for people who took part in the trial to share their experiences – please email James Barrow, Head of Public Affairs, at james.barrow@cysticfibrosis.org.uk.