OBJECTIVES: We previously reported persistence in the overall MS population and the current study examines the impact of age on persistence for all reimbursed DMTs for RRMS in Australia.

METHODS: This study used The Pharmaceutical Benefits Scheme 10% sample (supplied by Australia government). Eligible patients received a script for a reimbursed DMT for RRMS between September 2011 and February 2016. Patients were classified into five age-groups (ages 18-30; 31-40; 41-50; 51-60; 61+) and were defined as persistent if their DMT script was filled within 4 months. Persistence was derived using the Kaplan-Meier method and the relative rate of persistence was compared using hazard ratios (HR).

RESULTS

: A total of 1866 non-unique treatment episodes were eligible for the study. Overall the median persistence to therapy was 30 months with 68% of patients remaining on therapy for 12 months. Patients aged 18-30 had the shortest persistence (18 months) and a 44% increased risk of discontinuation when compared to the ‘all ages’ cohort (HR 1.44 (95%CI: 1.22-1.72) and was identified as a ‘high-risk’ group. For all other age-groups, when compared to Product Average, HR’s were between 1.08 and 0.92.

For patients aged 18-30 there was statistically significant lower persistence (median 9 months) on injectable therapy (glatiramer acetate, interferon beta-1a, interferon beta-1b) when compared to the persistent product average (median 18 months) with a hazard ratio of 1.95 (95% CI: 1.35-2.81). Patients on non-injectables (dimethyl fumarate, fingolimod, natalizumab, teriflunomide; n=188) had a median persistence of 24 months (HR 0.81(95% CI: 0.65-1.02 p=0.07). Further examination of individual drugs will depend upon availability of 100% PBS data.

CONCLUSIONS: In this analysis of PBS sample data, patients aged 18-30 were least persistent to treatment when compared to the product average. The persistence on injectable therapy was significant lower compared to all drugs in this high-risk group.