OBJECTIVES: To assess the cost-effectiveness of romiplostim as treatment for adult ITP splenectomized patients with refractory disease or non-splenectomized patients with surgery contra-indication, in comparison with the use of Intravenous Immunoglobulin (IVIg) rescue therapy only, from the Brazilian private health care perspective. METHODS: A cost per response model was developed. Overall response rates were derived from the romiplostim clinical trials (Kuter 2008) and were weighted by the proportion of patients splenectomized or not. The use of IVIg as rescue therapy in both arms was derived from Pullarkat, 2009. Treatment cost was calculated assuming drug wastage for an average patient weight of 72.4Kg and height of 170cm. Bleeding rates according to severity and site (gastrointestinal, intracranial and other) were estimated for patients without response considering data from Weitz, 2012. Resources and procedures used for the treatment of bleeding events were based on a medical specialist group recommendation and costs were obtained from official Brazilian databases. Gynecological bleed was used as a proxy for costs of other inpatient bleeds. The analysis assumed 50% splenectomized patients and was performed over a time horizon of 24 weeks. RESULTS: The average cost per patient over 24 weeks was R$60,509 for romiplostim (including rescue therapy and bleeding events costs) and R$173,319 for IVIg. 83.2% and 7.1% of patients in the romiplostim and IVIg arm respectively achieved overall response, leading to a cost per response equal to R$72,727 for romiplostim compared with R$2,424,047 for IVIg as rescue therapy.  CONCLUSIONS: The use of romiplostim in the treatment of ITP increases and maintains the platelet level of splenectomized and non-splenectomized patients and, at the same time, reduces the need of rescue therapy as IVIg. That generates cost savings and positions romiplostim as a dominant (less costly and more effective) strategy when compared with IVIg rescue therapy only.