Background/Purpose: Switching a biologic treatment or escalating biologic doses are common approaches used upon biologic treatment failure. The objective of this study was to estimate the one-year costs after switching to another tumor necrosis factor inhibitor (TNFi) versus increasing the dose of the same TNFi among patients with rheumatoid arthritis (RA).

Methods: This was a retrospective cohort study using administrative data for individuals in the HealthCore Integrated Research Databases (HIRD^SM). Initially, patients were included if they aged 18-63 with ≥1 claim for INF or ADA between Jul 1, 2009 and Jan 31, 2013, had ≥1 claim for RA during the 6 months prior to INF/ADA initiation, continuously enrolled between 6 months prior to and 12 months following INF/ADA initiation, and were not exposed to RA-related biologics 6 months prior to INF/ADA initiation or another condition for which RA-related biologics were approved to treat. Subsequently, INF/ADA patients switching to ADA/INF or ETN, or increasing the dose of the current drug in the subsequent year after treatment initiation were identified for further evaluation. Dose-escalation was defined for infliximab as having ≥120% of the expected infusions or an increase of ≥100 mg in dose; and for adalimumab as reaching a 40 mg weekly dose. Patients initiating ETN were not included in this analysis because dose-escalation in ETN has not been allowed per the approved US label. Patients who both dose-escalated and switched to a biologic of interest during the one-year follow-up were classified based on the first event. Costs were obtained from plan and patient paid amounts for biologic drug and administration and adjusted to 2013 dollar value.

Results: Of those who initiated ADA (n=1,437), 103 (7.2%) patients switched to INF/ETN and 103 (7.2%) patients increased their dose. Of those who initiated INF (n=539), 18 (3.3%) patients switched to ADA/ETN and 195 (36.2%) patients increased their dose. The average age was 48.6 (±10.2 [SD]) years and 74.7% were female. ADA initiators who dose-escalated on average incurred $8,843 higher costs compared with those who switched to another TNFi ($30,425 vs. $21,582, p<0.0001). INF initiators who dose-escalated on average incurred $9,022 higher costs compared with those who switched ($27,506 vs. $18,483, p=0.0007).

Conclusion: RA patients on ADA or INF incurred significantly higher costs when they dose escalated compared with switching to a new TNFi. The cost implications of increasing dose should be a consideration when making biologic treatment modifications in RA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/one-year-costs-following-switching-versus-dose-escalation-among-prevalent-tumor-necrosis-factor-inhibitors-used-for-rheumatoid-arthritis/