Rate and predictors of prescription of lumacaftor – Ivacaftor in the 18 months following approval in the United States

Rationale Lumacaftor-ivacaftor (LUM-IVA) was approved in the US in 2015 for patients with CF aged >12 homozygous for the delF508 mutation, and patients aged 6 to 12 in 2016. Objectives To examine the rate of initial LUM-IVA prescriptions following approval. Methods We compared patients eligible for LUM-IVA in the CF Foundation Patient Registry with and without prescriptions in 2015–2016. Results 5534 (53%) eligible patients had reported prescriptions. Prescription rate in children ages 6–11 was 19% and 61% among patients ≥12 years old. Individuals ≥12 with prescriptions more likely observed among those with private insurance, clinical trial participation, ages 18–30, FEV1 < 90%, more pulmonary exacerbations, and more use of chronic medications. Conclusions LUM-IVA uptake was less rapid than what was previously observed for ivacaftor, a CFTR modulator approved for a different population. Age, insurance status, disease severity and use of other therapies differed in those prescribed LUM-IVA in the initial post-approval period.