OBJECTIVES: There is limited real-world information on the utilization of thrombopoietin receptor agonists (TPO-RAs), including eltrombopag and romiplostim, for the treatment of immune thrombocytopenia (ITP) and their associated outcomes.

METHODS: The study employed a retrospective, longitudinal cohort design using 2 integrated healthcare claims databases (MarketScan and PharMetrics) from July 2008-September 2016. Adults diagnosed with ITP initiating TPO-RA therapy from January 2009-September 2015 were included. Patients not continuously enrolled in benefits for ≥6 months prior and ≥12 months post index date (first TPO-RA claim date) were excluded. The final cohort was followed for 12 months post-index date. Index TPO-RA adherence (medication possession ratio [MPR]), persistence (no gap of ≥30 days), and bleed-related events (BREs) were assessed.

RESULTS: After applying all study criteria, a total of 1,325 patients were identified via MarketScan: 365 (27.5%) eltrombopag and 959 (72.4%) romiplostim users, while PharMetrics revealed 1,010 patients: 297 (29.4%) eltrombopag and 713 (70.6%) romiplostim users. In MarketScan, a larger proportion of eltrombopag patients (76.7%) compared to romiplostim patients (44.4%), were adherent, as defined by an MPR≥0.8 (P<0.001). Similarly, a higher proportion of eltrombopag patients (34.8%) compared to romiplostim patients (27.6%), continued treatment (no gap of ≥30 days) for ≥1 year (P=0.011). During the follow-up period 63.6% of eltrombopag and 72.5% of romiplostim patients had a BRE (P=0.002). Results of PharMetrics analysis were similar to those of MarketScan.

CONCLUSIONS: ITP patients receiving eltrombopag were more adherent, had a longer duration of treatment, and had improved outcomes in terms of fewer BREs, compared to patients receiving romiplostim. Further research is needed to confirm the benefits of TPO-RAs among patients with ITP in real-world settings.