Key Points
• Switching to avatrombopag from another TPO-RA was safe in adult patients with ITP
• Patients experienced sustained effectiveness and enhanced overall treatment satisfaction after the switch
This phase 4, multicenter, open-label study was conducted to evaluate the safety, efficacy, and treatment satisfaction of switching to avatrombopag from another thrombopoietin receptor agonist (TPO-RA) in patients with immune thrombocytopenia (ITP). Adults who had received ≥90 days of treatment with eltrombopag or romiplostim and had a response (2 platelet counts [PCs] ≥50 × 109/L) switched to avatrombopag with no protocol-defined washout period. The primary endpoint was the incidence of treatment-emergent adverse events (TEAEs) and serious TEAEs. Secondary endpoints were the proportion of patients who had a PC between ≥50 × 109/L to ≤200 × 109/L (Days 15, 30, 60, and 90), and change from baseline in each domain of the self-administered Treatment Satisfaction Questionnaire for Medication (TSQM) to Day 90. Among 60 enrolled patients, 58.3% experienced TEAEs and 10.0% experienced serious TEAEs (1 related to avatrombopag [thrombocytopenia that resolved]; 5 unrelated [1 unrelated death]). A PC ≥50 × 109/L to ≤200 × 109/L was reported for 51.7%, 31.7% (mean [standard deviation] PC, 256.2 [176.7] × 109/L), 55.0%, 60.0%, and 55.0% at baseline and Days 15, 30, 60, and 90, respectively. TSQM scores increased from baseline to Day 90 across all domains (mean change: convenience, +13.5; effectiveness, +14.4; global satisfaction, +14.2; side effects, +8.3). There was no correlation of stable avatrombopag dose (Day 90) with prior TPO-RA dose (high or low). Patients with ITP may safely switch from another TPO-RA to avatrombopag and maintain adequate platelet counts while experiencing improved treatment satisfaction. NCT04638829
