POS1204 DISEASE ACTIVITY-GUIDED TAPERING OF BIOLOGICS INCLUDING BIOSIMILARS IS COST-EFFECTIVE IN PATIENTS WITH INFLAMMATORY ARTHRITIS: SECONDARY ANALYSES OF THE RANDOMISED BIODOPT TRIAL

Background:
Recently, the BIODOPT trial demonstrated that two-thirds of patients with inflammatory arthritis (IA) allocated to tapering could reduce their biological therapy and maintain low disease activity (LDA) at 18 months [1]. A very large proportion of patients in the study (78%) were treated with biosimilars and as cost savings are expected to be markedly lower when tapering biosimilars, these might not outweigh potential costs such as additional visits due to flare symptoms or biological switch due to persistent flare. Thus, a cost-effectiveness assessment of biological tapering including biosimilars is needed.
Objectives:
To assess cost-effectiveness of disease activity-guided tapering of biologics to continuation of biologics as usual care in patients with IA in sustained LDA.
Methods:
BIODOPT was a randomised, open-label, equivalence trial (EudraCT 2017-001970-41) in which adults with rheumatoid arthritis, psoriatic arthritis, or axial spondyloarthritis in sustained LDA were randomised 2:1 to disease activity-guided tapering or to continuation of biologics as usual care. The cost-effectiveness analysis included quality-adjusted life years (QALY), and hospital costs. Area under the curve of the Short Form Six Dimension (SF-6D) index, based on data from the Short Form 36 questionnaire, were used to calculate QALY. Hospital costs were defined as the sum of biological treatment costs and extra visit costs. Biological treatment costs included biological drug costs, costs related to switch to another biological drug due to persistent flare, and costs related to biologic administration i.e., infusion related costs including nurse salaries. All patients treated with adalimumab, etanercept, or infliximab were switched to biosimilars during the study period in accordance with national recommendations; thus, the biosimilar prices for these products were used. The cost-effectiveness analysis was performed as intention-to-treat. The mean SF-6D value in the relevant group at the specific time point were imputed if SF-6D values were missing. For patients lost to follow-up, it was assumed that the baseline biological dose remained unchanged after loss to follow-up. A two-sample t-test with unequal variance was applied to capture between-groups differences with means reported with 95% confidence intervals (95%CI).
Results:
In total, 142 patients were enrolled in the BIODOPT trial with 95 patients allocated to tapering and 47 patients to control [2]. During the study period, the SF-6D index did not differ between groups, Figure 1. Similarly, no statistically significant mean difference in QALY at 18-months was observed between groups: 0.008 points (95%CI: -0.008 to 0.024 points). Extra visits due to potential symptoms of flare were more frequent in the tapering group, between-group difference: 0.4 visit per patient per 18 months (95%CI: 0.02 to 0.81). Thus, yielding a statistically significant higher mean cost in the tapering group, between-group difference: 43€ (95%CI: 2 to 84€). Persistent flare led to switch to another biological drug in two patients from the tapering group (one due to IBD flare) and three patients in the control group. Thus, mean costs related to biological switch were highest in the control group but did not reach statistically significance, between-group difference: -125€ (95%CI: -327 to 76€). The tapering group had less outpatient visits to receive biologics (data not shown); thus, yielding a statistically significant lower mean cost for biological administration, between-group difference -167€ (95%CI: -291 to -44€). Costs for the biological products were lower in the tapering group but the between-group mean difference was insignificant: -1,686€ (95%CI: -3,536 to 163€). However, when the costs related to biological products, switch to another biological drug due to persistent flare, and biologic administration were combined, a statistically significant lower biological treatment cost was demonstrated in the tapering group, mean group difference: -1,979€ (95%CI: -3,798 to -161€). Furthermore, the tapering group had significantly lower hospital costs when combing biological treatment costs and extra visit costs; between-group difference: -1,936€ (95%CI: - 3,753 to -119€).
Conclusion:
Despite a high proportion of patients treated with biosimilars, the disease activity-guided tapering strategy proved to be cost-effective as a substantial reduction in hospital costs were observed without affecting QALY.