Patterns in use and costs of subsidising 5-aminosalicyclic acid compounds and biologic agents in the treatment of inflammatory bowel disease in Australia

TL;DR: The use and costs of subsidising -aminosalicyclic acid compounds (sulfasalazine, mesalazines, lsalazine, and balsalazide) from 2004 to 2015 and biologic agents from 2007 to 2015 to IBD in Australia are characterised.

Abstract: Not only is inflammatory bowel disease (IBD) debilitating to ndividuals, but the economic impact is high (>A$2.7 billion to the ustralian economy in 2005) [1]. The two main drivers of expeniture are hospitalisations and pharmacological treatments [2]. everal medicines are available for the treatment of IBD including -aminosalicylic acid compounds and biologic agents [3]. Many medicines are available to patients in Australia through he Pharmaceutical Benefits Scheme (PBS). The Australian govrnment subsidies the cost of each prescription that is dispensed nd patients contribute a co-payment [4]. Medicine use can be stimated by calculating the defined daily dose (DDD) per 1000 opulation per day (DDD/1000 population/day) [5]. The DDD is the ssumed average maintenance dose per day for a medicine used or its main indication in adults [5]. This methodology enables us to ompare different medicines and examine international consumpion patterns [5]. In Australia, PBS subsidised access to biologic agents is only for hose who have failed other therapies, with the exception of fistulisng Crohn’s disease, whereby immediate biologic use is allowed. To btain subsidised access to biologic agents in Crohn’s disease, the atient needs to fail a trial of both steroids and antimetabolite therpy. In ulcerative colitis, a patient with acute severe disease that ails steroid induction is allowed a three infusion course of inflixmab but to obtain ongoing PBS access to biologic therapies, the atient needs to show a failure of response to both 5-aminosalicylic cid compounds and antimetabolite therapy. We have characterised the use and costs of subsidising -aminosalicyclic acid compounds (sulfasalazine, mesalazine, lsalazine, and balsalazide) from 2004 to 2015 and biologic agents adalimumab, infliximab and vedolizumab) from 2007 to 2015 to reat IBD in Australia. Only prescriptions dispensed specifically or Crohn’s Disease or ulcerative colitis were considered. Item umbers of these medicines were used to retrieve the number f dispensed prescriptions and costs for each medicine from the edicare Australia PBS statistics website [6]. Data were analysed y medicine class and indication. Medicine use was calculated using he DDD/1000 population/day [5]. Medicines introduced to the PBS art-way through the calendar year were adjusted appropriately. ata were available in the public domain and hence ethics approval as not required. 5-Aminosalicylic acid compounds; mesalazine, sulfasalazine

Summary

Introduction

• To appear in: Digestive and Liver Disease Please cite this article as: Kong David P, Hollingworth Samantha A.Patterns in use and costs of subsidising 5-aminosalicyclic acid compounds and biologic agents in the treatment of inflammatory bowel disease in Australia.
• The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form.

Keywords

• Pharmacoepidemiology, expenditure, adalimumab, infliximab Dear Editor, Not only is inflammatory bowel disease (IBD) debilitating to individuals, but the economic impact is high (>A$2.7 billion to the Australian economy in 2005). [1].
• The authors have characterised the use and costs of subsidising 5-aminosalicyclic acid compounds (sulfasalazine, mesalazine, olsalazine, and balsalazide) from 2004 to 2015 and biologic agents (adalimumab, infliximab and vedolizumab) from 2007 to 2015 to treat IBD in Australia.
• Medicine use was calculated using the DDD/1,000 population/day.[5].
• The use and costs of some biologics remains low: infliximab in ulcerative colitis was only subsidised in 2014; adalimumab from December 2016; and vedolizumab in 2015 for both Crohn’s disease and ulcerative colitis. [4].
• The increased use of 5-aminosalicylic acid compounds is mostly due to increasing use of mesalazine.

Conflicts of interest

• Christine Staatz, David Kong and Samantha Hollingworth have no conflicts of interest associated with authorship of the manuscript ‘Inflammatory bowel disease in Australia: AC CE PT ED M AN US CR IP T patterns in use and costs of medicines’.
• Neal Martin reports grants and personal fees from Ferring and personal fees from Takeda, Janssen, Abbvie, Shire, Baxter, Pfizer outside the submitted work.
• This study was funded from existing salaries.
• David Kong was a BPharm(Hons) student during the study.

Acknowledgments

• The authors would like to thank Prof Gerald Holtmann for his efforts in reviewing the manuscript.
• Author contributions were as follows: study concept and design (CS, SH); data acquisition, management, analysis, interpretation, and drafting of the manuscript (CS, NM, DK & SH); and critical revision of the manuscript (CS, NM, DK & SH).

Figure legends

• Dispensed use (defined daily dose [DDD] per 1,000 population per day) for (a) adalimumab across different indications and for adalimumab and infliximab in total and (b) infliximab across different indications and for adalimumab and infliximab in total;, also known as Figure 2.
• Cost to government (A$) of (c) adalimumab across different indications and for adalimumab and infliximab in total and (d) infliximab across different indications and for adalimumab and infliximab in total in total.
• Results for vedolizumab not provided as first subsidised in 2015.
• Indications for the biologics include Crohn's disease (CD), Crohn's disease fistulising (CDF), Crohn's disease paediatric (CDP), and ulcerative colitis (UC).

Figures

Figure 1: Dispensed use (defined daily dose [DDD] per 1,000 population per day) (a) and cost to government (A$) (b) for the four individual 5-aminosalicylic acids for ulcerative colitis.