bDMARDs for ankylosing spondylitis, February 2016
Page last updated: 8 July 2016
Drug utilisation sub-committee (DUSC)
February 2016
Abstract
Purpose
To examine the PBS use of biological disease modifying anti-rheumatic drugs (bDMARDs) used to treat ankylosing spondylitis.
Date of listing on the Pharmaceutical Benefits Scheme (PBS) for this indication
- Infliximab: 1 August 2004
- Etanercept: 1 April 2005
- Adalimumab: 1 March 2007
- Golimumab: 1 August 2010
- Certolizumab pegol: 1 September 2014
Data Source / methodology
The Department of Human Services (DHS) Authority Approvals database was used for most patient level analyses (eg. patient counts, continuation rates and drug sequence). The DHS prescription claims database and the DUSC Highly Specialised Drugs database were used for prescription count and expenditure analyses.
Key Findings
- The number of patients on bDMARD treatment for ankylosing spondylitis (AS) has increased from the time of listing, from 628 in 2005 to 6,106 in 2014 with no indication of plateauing.
- The number of patients initiating bDMARD treatment for AS per year has increased from 453 in 2005 to 1,190 in 2014. Each time a new drug is listed on the PBS there was a slight step up in the number of initiating patients followed by a plateauing. This may be influenced by patient access programs and grandfathering of patients to PBS subsidised supply following listing.
- Adalimumab is the most commonly used bDMARD, followed by etanercept and golimumab. Infliximab has low and stable use. Certolizumab pegol was only recently listed and has yet to establish market share.
- Treatment continuation is high with 69-84% of new patients receiving a second authority approval for their initial bDMARD, and 91% receiving a second approval for any bDMARD. This is higher than anticipated based on response rates in the key clinical trials.
- The majority of people remain on bDMARD therapy for long durations. For example, 72% of patients who began treatment in 2009 have received at least 10 authority approvals.
- 62% of patients who commenced bDMARD therapy prior to 2014 have received an authority for a single bDMARD, with 27% receiving authority approvals for two bDMARDs, 9.2% for three bDMARDs, and 2.2% for more than three bDMARDs.
- Commonwealth expenditure on bDMARDs for ankylosing spondylitis has increased each year, reaching $107.4 million in 2014.
