Romiplostim dose and variability in doses received. (A) Mean (SE) doses of romiplostim (μg/kg) by study week. Over the course of the study, the mean (±SD) total number of doses of romisplostim was 63.2 (±37.1), the mean (±SD) duration of treatment was 69 (±39.4) weeks, and the mean (±SD) average weekly dose was 5.9 (±3.9) μg/kg. The overall mean dose of romiplostim increased over the first 24 weeks and then remained relatively constant. (B) Variability in doses received. Percentage of weeks during which patients' doses changed by greater than 2 μg/kg from the patient's most frequent dose (excluding weeks 1-12; n = 133). After the first 12 weeks of treatment, in 77% of patients (103/133), romiplostim doses were within 2 μg/kg of the patient's most frequently administered weekly dose greater than 90% of the time.