Impact of a Patient Support Program on time to discontinuation of adalimumab in Australian adult patients with immune-mediated inflammatory diseases–an observational study

Abstract

This observational study evaluated the impact of a sponsor company-provided Patient Support Program (PSP) on discontinuation of adalimumab in adult Australian patients eligible for Pharmaceutical Benefit Scheme (PBS)-reimbursed adalimumab for Rheumatoid Arthritis (RA), Ankylosing Spondylitis (AS), Psoriatic Arthritis (PsA), Crohn’s Disease (CD), Ulcerative Colitis (UC), or Hidradenitis Suppurativa (HS). Patients initiating adalimumab between May 2018 and September 2019 were enrolled into two prospective cohorts based on their decision to opt for or decline the PSP (PSP or non-PSP cohorts). In addition, a historical, retrospective Non-PSP cohort was established from the Services Australia 10% PBS dataset by extracting data of patients initiating adalimumab prior to the introduction of adalimumab PSPs and based on adalimumab PBS listing dates (AS: April 2007 to March 2009; PsA/RA: January 2007 to December 2008; CD: January 2009 to December 2010; HS and UC indications not included). Follow-up for all cohorts was 12 months. The primary endpoint was the time to discontinuation, compared between the prospective PSP cohort and the prospective or retrospective Non-PSP cohort. Inverse probability of treatment weighting was used to balance the cohorts. A Cox proportional hazards model indicated no difference in time to discontinuation between the prospective PSP (n = 162) and non-PSP (n = 65) cohorts (HR [95% CI] = 1.256 [0.616–2.563], p = 0.5304). The 12-month adalimumab persistence rates (95% CI) were 78% (69%, 84%) and 82% (67%, 90%), respectively. In contrast, discontinuation was less likely in the prospective PSP (n = 151) compared with the retrospective non-PSP (n = 297) cohort (HR [95% CI] = 0.44 [0.28–0.68], p<0.001). The 12-month persistence rates (95% CI) were 81% (76%, 90%) and 61% (56%, 67%), respectively. Overall, this study suggests that optimal adalimumab persistence can be achieved with either a structured PSP or healthcare support from other sources, but this was not the case more than a decade ago.