Patient-reported outcomes of avatrombopag for chronic immune thrombocytopenia: Interim analysis of the Phase 4 adopt study

Abstract Introduction: Avatrombopag (AVA) is a thrombopoietin receptor agonist (TPO-RA) widely approved for the treatment of patients with chronic immune thrombocytopenia (ITP). Because ITP and its treatment can substantially impact patients' health-related quality of life (HRQoL), evaluating patient-reported outcomes (PROs) is critical in capturing the holistic impact of treatment on the patient experience. Here, we present updated interim efficacy, safety, and PROs from ADOPT, an ongoing phase 4, multicenter study examining European real-world outcomes with AVA in clinical practice. Methods: Patients aged ≥18 years with an established ITP diagnosis who were initiating or already being treated with AVA were enrolled at 51 sites across 9 European countries. Data were collected retrospectively for up to 12 months prior to initiation of AVA treatment, and prospectively for up to 12 months after study enrollment (follow-up period). The primary endpoint was the cumulative number of weeks with a platelet count (PC) ≥30×109/L. Key secondary endpoints were the cumulative number of weeks with PC ≥50×109/L; changes in PROs, including health status assessed by the EuroQol 5-dimension, 5-level questionnaire (EQ-5D-5L), fatigue-related HRQoL assessed by the 13-item Functional Assessment of Chronic Illness Therapy–Fatigue (FACIT-Fatigue), ITP-specific HRQoL assessed by the 44-item Immune Thrombocytopenic Purpura Patient Assessment Questionnaire (ITP-PAQ), and the impact of ITP on work and nonwork activities assessed by the 6-item Work Productivity and Activity Impairment Questionnaire (WPAI); and adverse events (AEs). Results: As of February 28, 2025, the full analysis set comprised 199 patients (mean age: 56.3 years; 55.3% female). The mean (standard deviation [SD]) time from ITP diagnosis to study enrollment was 9.7 (11.5) years, and 59.3% of patients had been treated with another TPO-RA within the previous 12 months. During the follow-up period, the median AVA dosing duration was 52.3 weeks, and the median cumulative number of weeks with PC ≥30×109/L and ≥50×109/L was 44.1 (range: 0.0–52.3) and 39.7 (range: 0.0–52.3) weeks, respectively. Among patients with available data, the proportion reporting no problems with mobility on the EQ-5D-5L increased from 63.6% (70/110) at enrollment to 73.3% (44/60) at month 12; similar patterns were observed for the proportion of patients reporting no pain/discomfort (enrollment: 45.5% [50/110]; month 12: 53.3% [32/60]) and no anxiety (enrollment: 57.3% [63/110]; month 12: 65.0% [39/60]). The mean (SD) FACIT-Fatigue score improved from 36.8 (12.2) at enrollment to 39.3 (10.3) at month 12. Mean (SD) ITP-PAQ scores were higher at month 12 vs enrollment across multiple scales, indicating better HRQoL (symptoms: 82.8 [12.3] vs 79.3 [15.6]; activity: 78.6 [26.9] vs 75.2 [26.2]; psychological health: 83.9 [19.5] vs 76.2 [26.0]; work: 72.1 [30.1] vs 62.1 [30.5]; social activity: 85.6 [15.9] vs 79.9 [21.3]; overall QoL: 66.4 [19.7] vs 61.1 [24.3]). Mean (SD) WPAI scores at month 12 vs enrollment showed substantial decreases in absenteeism (7.7 [22.9] vs 15.9 [33.3]), presenteeism (14.5 [24.1] vs 20.3 [24.7]), overall work impairment (17.6 [25.7] vs 23.2 [26.3]), and nonwork activity impairment (24.9 [29.9] vs 27.0 [29.5]). AEs were reported in 18.1% (36/199) of patients, with 25 patients experiencing serious AEs, 11 experiencing AVA-related AEs, and 4 discontinuing AVA treatment because of AEs, including headache and deep vein thrombosis (1 report each). Conclusions: This interim analysis of the ADOPT study supports the real-world effectiveness and safety of AVA for treating people with ITP. Improvements in PROs, including health status, HRQoL, and ITP-related activity impairment, in addition to clinical outcomes, underscore the potential of AVA to benefit patients with ITP.