Ivacaftor for cystic fibrosis, February 2018
Page last updated: 22 August 2018
Drug utilisation sub-committee (DUSC)
February 2018
Abstract
Purpose
To compare the predicted and actual utilisation of ivacaftor for cystic fibrosis (CF) since Pharmaceutical Benefits Scheme (PBS) listing on 1 December 2014.
Listing on the Pharmaceutical Benefits Scheme (abridged)
Cystic fibrosis patients with a G551D mutation in the CFTR gene on at least 1 allele, or another gating (class III) mutation in the CFTR gene on at least 1 allele.
To qualify for initial PBS therapy, a patient must have a sweat chloride value of at least 60 mmol/L by quantitative pilocarpine iontophoresis.
For the full restriction, refer to the PBS schedule.
Data Source
Department of Human Services (DHS) PBS prescription data for dates of supply from 1 December 2014 to 30 September 2017, inclusive.
Key Findings
- Since its listing in December 2014, a total of 268 patients have been supplied ivacaftor for CF.
- The number of patients treated with ivacaftor in each of the first two years of listing was less than predicted. This may be due to an overestimation of the proportion of the CF population having a G551D mutation.
- The number of prescriptions per patient was higher than predicted. This may be due to higher adherence and/or less dose reduction for patients with hepatic impairment or concomitant CYP3A4 inhibitor use than anticipated.
- Overall expenditure was close to that predicted in the submission (notwithstanding performance rebates).
