Use of a Thrombopoietin Mimetic for Chronic Immune Thrombocytopenic Purpura in Pregnancy

BACKGROUND: Romiplostim, a thrombopoietin mimetic, is a novel therapeutic option for patients with chronic immune thrombocytopenic purpura. We report on the effects of romiplostim use throughout pregnancy. CASE: A 28-year-old primigravid woman with chronic immune thrombocytopenic purpura initiated a planned pregnancy on romiplostim. The second and third trimesters were marked by a cyclic pattern of thrombocytopenia requiring supplemental corticosteroids or intravenous immunoglobulin and resultant thrombocytosis. Increased romiplostim doses and daily corticosteroids stabilized the platelet count before induction of labor at 33 weeks of gestation. The newborn manifested intraventricular hemorrhage at birth, although no developmental delay was present on follow-up at 10 months of age. CONCLUSION: The decreased efficacy of romiplostim monotherapy is attributed to increased target-mediated drug disposition and the physiologic changes of pregnancy. Safety concerns still exist for the developmental effects of romiplostim on the fetus.