Cost-consequence model comparing eltrombopag and romiplostim in pediatric patients with chronic immune thrombocytopenia

BACKGROUND: Immune thrombocytopenia (ITP) is an auto-immune disorder characterized by enhanced platelet destruction and, subsequently, the potential for increased bleeding. Thrombopoietin receptor (TPO-R) agonists have recently emerged as promising therapies for ITP patients who are refractory to other treatments. While eltrombopag (EPAG) is the only TPO-R agonist US Food and Drug Administration approved for use in pediatric patients, romiplostin (ROMI) has been used in Phase III clinical studies. METHODS: A cost-consequence model (CCM) was developed to evaluate the costs of EPAG, ROMI, and watch-and-rescue (W&R) in relation to their respective treatment outcomes in previously-treated pediatric chronic ITP (cITP) over a 26-week time horizon. The costs of drugs, administration, routine care, rescue medications, adverse events, and mortality were included. Data on platelet count response rate, bleeding events, and adverse events were derived from all relevant identified Phase III-registered clinical trials, health outcomes were compared via indirect treatment comparison. RESULTS: The overall estimated cost of EPAG per patient was US$66,550, compared to US$101,056 for ROMI and US$32,720 for W&R. EPAG’s lower cost compared to ROMI was largely due to lower drug costs (US$62,202 vs US$84,396), administration costs (US$0 vs US$1,955), and significantly lower costs due to severe bleeding (US$354 vs US$10,191). When assessing cost per severe bleeding event avoided, EPAG was dominant over ROMI (less expensive and more effective). EPAG was again dominant over ROMI when assessing the cost per responder and per bleeding event (any grade). Sensitivity analysis was consistent with the base case findings. CONCLUSION: EPAG was the preferred TPO-R agonist to treat cITP when indirectly compared to ROMI, largely driven by its favorable severe bleeding outcomes and lower drug and administration costs.