(007) Determining lines of therapy in real world patients with rheumatoid arthritis: analyses of a nationwide claims database in Japan

Background: Determining lines of therapy (LOT) for rheumatoid arthritis (RA) with disease-modifying anti-rheumatic drugs (DMARDs) is crucial for discerning the gap between real-world treatment decisions and current clinical practice guidelines and assessing safety concerns among DMARDs.

Objectives: To determine LOT in RA patients in Japan.

Methods: We used the Japanese nationwide administrative claims database (NDB) and identified adults (≥18 years) with RA initiated DMARDs (conventional synthetic [csDMARDs], biologic [bDMARDs], and targeted synthetic [tsDMARDs]). We excluded those with prior malignancy, psoriasis, and psoriatic arthritis. Among those initiating csDMARDs as 1st LOT, we estimated the 1-year cumulative incidence of initiating b/tsDMARDS as 2nd LOT either with or without csDMARDs, accounting for censoring and the competing risk of treatment discontinuations and switching to non-b/ts treatments. The assessment was repeated for the 1-year cumulative incidence of initiating new bDMARDs or tsDMARDs with or without csDMARDs among 2nd LOT bDMARDs initiators. We conducted the assessment separately for years 2014 and 2018. Baseline characteristics of the patients were compared between those switching to tsDMARDs and bDMARDs.

Results: Among 517,304 RA patients who initiated any DMARDs (71% women, median age 65 years), 96.4% initiated csDMARD monotherapy, 3.0% bDMARD monotherapy, 0.2% tsDMARDs monotherapy and 0.4% combination therapy. Among 71,550 patients initiating 1st line csDMARDs in 2014, 8.1% initiated bDMARDs and 0.1% initiated tsDMARDs within one year. Among 64,014 patients initiating first line csDMARDs in 2018, 10.6% started bDMARDs and 0.7% started tsDMARDs within one year. Among 5,271 patients initiating bDMARDs as 2nd LOT in 2014, 19.2% shifted to another bDMARDs (2nd bDMARDs), and 0.7% switched to tsDMARDs within a year. Among 11,069 patients initiating bDMARDs as 2nd LOT in 2018, 17.3% transitioned to 2nd bDMARDs and 2.8% switched to tsDMARDs within one year. Patients prescribed tsDMARDs as 2nd LOT were more likely older, male, and had emphysema and interstitial lung disease, compared to those on bDMARDs. The characteristics of the patients using tsDMARDs as their 3rd LOT were similar to those using bDMARDs as their 3rd LOT.

Conclusions: Switching in the DMARDs occurred more quickly for the 3rd LOT compared to the 2nd LOT, with increasing utilization of tsDMARDs over the study period. A comparative assessment should consider this evolving treatment pattern, taking into account prescription timing and treatment duration.