Little to separate Vertex’s cystic fibrosis triplets

With seemingly very little to differentiate its two new cystic fibrosis assets Vertex has decided to wait for longer-term data to mature before making a decision on which one to file. A topline look at the second project, VX-445, was released today, and its effectiveness is remarkably close to that of VX-659. Both are to be combined with tezacaftor and ivacaftor (Kalydeco), Vertex’s existing therapies, and are being tested in patients homozygous for the F508del mutation in the CFTR  gene, and in patients with one copy of the F508del mutation and one minimal function mutation (known as F508del/Min). The numbers are so close, in fact, that the company might rue the decision to invest in two late-stage clinical programmes, rather than picking one over the other earlier. Either way, 24-week data due in the next couple of months will be used to pick the winner, and Vertex pledged to file in the third and fourth quarters, in the US and EU respectively. This is slightly later than expected, but with little real competition on the horizon in cystic fibrosis investors are unlikely to be concerned. 

Picking a triple, or Vertex's quandary
  VX-445, tezacaftor and ivacaftor  VX-659, tezacaftor and ivacaftor 
  F508del/Min F508del homozygous F508del/Min F508del homozygous
Improvement over baseline in mean ppFEV1 at wk 4 13.8 points 10.0 points 14.0 points 10.0 points
P value vs placebo <0.0001 <0.0001 <0.0001 <0.0001
ppFEV1=percent predicted forced expiratory volume in one second. Source: company press releases.

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