[7][8][9] Ivacaftor was developed by Vertex Pharmaceuticals in conjunction with the Cystic Fibrosis Foundation and is the first medication that treats the underlying cause rather than the symptoms of the disease.

[13][3][14] Ivacaftor is also included in a combination product, lumacaftor/ivacaftor, in a single pill, which is used to treat people with cystic fibrosis who have the F508del mutation in CFTR.

[23][4] Ivacaftor was developed by Vertex Pharmaceuticals in conjunction with the Cystic Fibrosis Foundation and is the first medication that treats the underlying cause rather than the symptoms of the disease.

The cost of ivacaftor is US$311,000 per year, roughly similar to the price of other medications for extremely rare diseases.

[36] An editorial in JAMA called the price of ivacaftor "exorbitant", citing the support by the Cystic Fibrosis Foundation in its development and the contribution made by fundamental scientific research performed by the National Institutes of Health and relied upon by Vertex in its cystic fibrosis drug discovery programs.

"[38] The Cystic Fibrosis Foundation, a non-profit organization dedicated to improving healthcare for people with cystic fibrosis, provided $150 million of the funding for the development for ivacaftor in exchange for royalty rights in the event that the medication was successfully developed and commercialized.

[39][40] Vertex said it would make the medication available free to patients in the United States with no insurance and a household income of under $150,000.

UK agencies estimated the cost per quality adjusted life year (QALY) at between £335,000 and £1,274,000 —well above the National Institute for Health and Care Excellence thresholds.

[44] Delay in agreement on a price for Vertex to charge national health plans led to patient group protests in Wales,[45][46] England,[47] and Australia.

[50][51] The safety and efficacy of ivacaftor for the treatment of cystic fibrosis in patients with this mutation was examined in two clinical trials.

[citation needed] The first trial was performed in adults having baseline respiratory function (FEV1) between 32% and 98% of normal for persons of similar age, height, and weight.

At the end of 48 weeks, people treated with ivacaftor had on average an absolute increase in FEV1 of 10.4%, vs. a decline of 0.2% in the placebo group.

[3] A third clinical trial examined the efficacy of ivacaftor in people with cystic fibrosis due to G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, or S549R mutations.

At week 8, the people on treatment with ivacaftor experienced an average absolute improvement in FEV1 of 13.8%, but there was a strong dependence of the efficacy on the exact mutation that a patient had.