Patients with ≥ 20 × 109/L Platelets at Baseline May Have a Prompt Response to Romiplostim During the Early Phase of Treatment: an Italian Single-Institution Experience

Patients with chronic immune thrombocytopenia treated with romiplostim may benefit from a higher starting dose when a rapid increase in count is needed, but it could be avoided in those with a prompt response to the standard dosage. We hypothesized that a platelet count ≥ 20 × 10(9)/l at baseline could distinguish subjects with such response from those with a delayed one during the early phase of treatment. Our work is a retrospective and single-institution analysis comparing the median platelet count, the median weekly dosage of romiplostim and the median number of weekly platelet counts < 50 × 10(9)/l between patients with a baseline ≥ 20 × 10(9)/l platelets (n=10, 2 splenectomized) and those with a lower one (n=8, 3 splenectomized) during the first month of treatment with romiplostim. The results show a higher median platelet count (79,5 vs 40,5 × 10(9)/l, p=0,002) and a lower median dose of romiplostim (1 vs 2 mcg/kg/week, p=0,01) in subjects with a baseline ≥ 20 × 10(9)/l platelets, who also had a trend of less weekly counts < 50 × 10(9)/l platelets (1 vs 2, p=0,054). These data suggest that patients with ≥ 20 × 10(9)/l platelets at baseline may achieve a prompt response with the standard dose of romiplostim, but further and larger data are needed in order to assess whether it can be considered in clinical practice.