PF696 SAFETY AND EFFICACY OF SELF‐ADMINISTERED ROMIPLOSTIM IN PATIENTS WITH IMMUNE THROMBOCYTOPENIA (ITP): RESULTS OF AN INTEGRATED ANALYSIS OF FIVE CLINICAL TRIALS

Abstract

Background:In chronic ITP, subcutaneous administration of romiplostim by a healthcare professional (HCP) is approved in many countries. Self‐administration (SA) by patients/caregivers can offer time and cost savings to providers and is convenient for patients because the need for weekly clinic visits is eliminated. SA is available in Europe for trained patients with stable platelet count (≥50 x 109/L for ≥4 weeks [wks] without dose adjustment).Aims:This analysis examined the safety and efficacy of romiplostim SA.Methods:Data were pooled from 5 romiplostim clinical trials in adults (≥18 years) with ITP. In all trials, and at investigators’ discretion, patients who achieved a stable dose for ≥3 consecutive wks (≥4 wks in 3 trials; ≥3 wks in 2 trials) could self‐inject romiplostim (or have it administered by a caregiver). The SA analysis group included patients who ever self‐administered romiplostim in any of these 5 trials. To provide a meaningful comparator, an HCP‐dosed subgroup of patients from the 5 trials were included in the analysis. Patients in this comparator subgroup were required to have received the same stable romiplostim dose for ≥5 consecutive wks (duration selected to provide a conservative comparison) with platelet response and with all doses administered by an HCP. Thus, patients in the HCP comparator group may have been eligible for SA provided they had received physician approval and adequate training. In the SA group, the analysis index date was the 1st day a patient self‐injected romiplostim. In the HCP group, the index date was the date of the 5th consecutive stable dose. Safety parameters were adjusted for differences in romiplostim treatment duration in the SA and HCP groups (duration‐adjusted values reported herein). Platelet response was defined as weekly platelet counts ≥50 x 109/L without any use of rescue medication within 4 wks prior to date of the platelet measurement. Statistical analyses were descriptive.Results:At baseline, in the SA (N = 621) vs HCP (N = 133) groups, respectively, median age was 53 vs 58 years, median time since primary ITP diagnosis was 3.7 vs 2.5 years, median baseline platelet count was 19 vs 20 × 109/L, and 34% vs 28% had undergone splenectomy. Median romiplostim treatment duration was 89 and 52 wks for SA and HCP groups, respectively. Respective median total number of doses were 81 and 50. The median weekly romiplostim dose was 3.6 μg/kg in the SA group and 3.1 μg/kg in the HCP group. As shown in the table, duration‐adjusted event rates were numerically lower in the SA vs HCP group for all treatment‐emergent adverse events (TEAEs), Grade ≥3 TEAEs, serious TEAEs, TEAEs leading to discontinuation and fatal TEAEs. Duration‐adjusted rates of bleeding TEAEs, Grade ≥3 bleeding TEAEs and serious bleeding TEAEs were also numerically lower for the SA vs the HCP group (see Table). Following the index date, 95% of patients in the SA group and all patients (100%) in the HCP group achieved a platelet response at least once during the analysis period. The median % of wks in response in the SA vs HCP groups were 95% vs 96%, respectively. Overall, rescue medication was used in 37% vs 40% of patients in the SA vs HCP groups, respectively. Adjusting for the duration of treatment, the romiplostim dose adjustment rates/100 subject‐wks were 1.24 vs 1.60 in the SA vs HCP groups, respectively.Summary/Conclusion:Romiplostim self‐administration appears well tolerated and effective in eligible patients with ITP who have stable platelet counts ≥50 × 109/L for ≥4 consecutive wks and have undergone training.image