TPO-RA treatment and response
Data on TPO-RA treatment and response are summarized in Table 3. Ten patients (67%) received romiplostim and five (33%) received eltrombopag. The median starting dose for eltrombopag was 50 mg daily (range 50-200mg daily) and 2 mcg/kg (1-10 mcg/kg daily) for romiplostim. The median duration of treatment was four weeks for romiplostim (range: 1-32 weeks) and six weeks for eltrombopag (range: 3-20 weeks).
Platelet trends for each patient are shown in Fig. 1 . The median baseline platelet count was 24 x 109/L(range: 2-119 x 109/L). There was no significant difference at one week after TPO-RA initiation (p = 0.145). Significant increases in platelet counts were observed at two weeks (p = 0.031), three weeks (p = 0.031), and four weeks (p = 0.031) of initiating a TPO-RA.
Fourteen patients (93%) achieved a sustained platelet count of 50 x 109/L or greater, with a median time to response of 3 weeks (range 1-8 weeks). Ten patients (67%) achieved a platelet count of 100 x109/L or greater following TPO-RA administration within eight weeks (range 2-8 weeks) , including 82% of patients who received romiplostim and 25% of patients who received eltrombopag. The peak platelet count recorded was 1,036 x 109/L in a patient receiving romiplostim at 10mcg/kg (patient 12). The median platelet count at three weeks was 66 x 109/L for patients who received romiplostim and 49 x 109/L for patients who received eltrombopag.
There was a statistically significant reduction in platelet transfusion requirements following TPO-RA initiation (Fig. 2). The median number of transfusions (platelet units) required in the month prior to treatment was 15 (range: 0-62), which decreased to two (range: 0-30) during the first four weeks post-treatment (p = 0.004).