OBJECTIVES: Romiplostim stimulates platelet production via the thrombopoetin-receptor and is recommended for second- and third-line treatment of chronic ITP in adults. Traditional treatment options in this setting have included unapproved use of the immunosuppressant rituximab. This analysis assessed the cost per responder of romiplostim compared to rituximab in adult ITP patients in France. METHODS: A decision analytic model was developed to estimate the six-month cost per patient responding to treatment.  A systematic literature review was performed to obtain response rates (achieving a platelet count ≥50x109/L) for each treatment. Romiplostim patients received weekly administrations; rituximab patients received 4 weekly intravenous infusions. Resource utilization was based on French and international treatment guidelines, and clinical expert opinion. Unit costs were derived from published literature and French reimbursement lists, and included the costs of routine physician visits, treatment administration and emergency care. Non-responders incurred the cost of rescue therapy (IVIg and prednisone) and hospitalizations/physician visits associated with bleeding-related events (BREs). RESULTS: Although the comparability of existing literature for romiplostim and rituximab was limited, several fulfilled the literature review selection criteria. Response rates were 83% and 62.5%, as per the romiplostim pivotal trial and a meta-analysis on rituximab, respectively. Mean cost per patient for romiplostim and rituximab was €17,486 and €17,086, respectively.  Dividing mean cost per patient by response rates, cost per response was €21,067 for romiplostim and €27,337 for rituximab. The main cost-offsets were due to reduced rescue therapy and BREs, with romiplostim resulting in a 23% reduction in cost per platelet response. Across sensitivity analyses, romiplostim consistently produced a lower cost per response.  CONCLUSIONS: In adult ITP patients, romiplostim yields a lower cost per response over 6 months compared to rituximab, indicating romiplostim represents an efficient use of resources for the French health care system.