Antithrombotic and hemostatic stewardship: Evaluation of romiplostim for treatment of thrombocytopenia at a large academic medical center

Romiplostim is indicated for immune thrombocytopenia (ITP), though is often used off-label for other indications such as chemotherapy-induced thrombocytopenia (CIT) and thrombocytopenia post hematopoietic stem cell transplantation (HSCT). Although romiplostim is FDA approved at a starting dose of 1 mcg/kg, it is often initiated at 2–4 mcg/kg depending on the severity of thrombocytopenia in clinical practice. Given the limited data, but interest in higher doses of romiplostim for indications other than ITP, we aimed to assess our inpatient romiplostim utilization at NYU Langone Health.

This was a single-center, retrospective review of 84 adult patients from January 2019 to July 2021. The top three indications were ITP (51, 60.7%), CIT (13, 15.5%), and HSCT (10, 11.9%). The median initial romiplostim dose was 3.8 mcg/kg (range, 0.9–10.8). 51% of patients achieved a platelet count of ≥50 × 10⁹/L by the end of week 1 of therapy. For patients achieving goal platelets by the end of week 1, the median dose of romiplostim was 2.4 mcg/kg (range, 0.9–10.8). There was 1 episode of thrombosis and 1 episode of stroke.

We found that higher than FDA-recommended initial doses should be considered to achieve a platelet response. It appears to be safe to initiate romiplostim as higher doses, and to increase doses by greater increments than 1 mcg/kg in order to achieve a platelet response. Future prospective studies are needed to confirm the safety and efficacy of romiplostim in off-label indications and should evaluate clinical outcomes such as bleeding and need for transfusions.