Background Romiplostim increases platelet counts in ITP and is typically injected at clinic visits.
Objective To estimate the efficacy and safety of romiplostim self-administration, we evaluated data from an open-label extension study in a post hoc analysis.
Methods Patients received weekly romiplostim with dose adjustments to target platelet counts of 50-200 x 109/L. Patients with a stable dose and platelet counts of 50-200 x 109/L for 3 or more weeks could begin self-administration if investigators deemed it appropriate, returning to study sites every 4 weeks.
Results Of 292 patients, 239 (82%) initiated self-administration for a median of 74 (Q1-Q3:56-164) weeks. Twenty-eight of the 239 (12%) discontinued self-administration (investigator or sponsor decision: 19, patient request: 6, noncompliance: 3). The median average weekly dose for patients self-administering romiplostim was 4.1 g/kg. The romiplostim dose was adjusted in 40 (17%) of the 239 patients in the first 8 weeks of self-administration; 84 (35%) in the first 6 months. Patients had a platelet response (more than 50 x 109/L) for a mean of 75.1% of weeks. The adverse event (AE) rate was 18.3/100 patient-weeks, with 0.8 serious AEs/100 patient-weeks. Fourteen AEs led to withdrawal; none related to self-administration.
Limitations The analysis was post hoc. Lack of a randomized comparator group may have resulted in differences between patient populations. No distinctions could be made between constant and intermittent self-administration or between adverse events occurring during self-administration or administration at the study site.
Conclusions Patients were able to maintain platelet responses for a mean of 75% of the time without new safety issues while self-administering romiplostim.
To read the full article, click on the PDF icon at the top of this introduction.