Therapeutic management and costs of severe haemophilia A patients with inhibitors in Italy.

Haemophilia A (HA) patients with high responding inhibitors require therapies with bypassing agents to control bleedings or Immune Tolerance Induction (ITI) to attempt inhibitor eradication and restore FVIII therapy. The aim of this study was to assess the therapeutic management and product consumption of HA inhibitor patients and the relative costs in Italy. A retrospective survey was performed utilizing data from the National Registry of Congenital Coagulopathies and from a specific questionnaire on product consumption of HA inhibitor patients over the year 2011. Among HA patients, 10\% had currently detectable inhibitors; 24\% of patients were undergoing ITI (mostly children) and 76\% utilized bypassing agents. Patients on ITI consumed 45,000,000 IU of FVIII (median consumption/patient of 1,200,000 IU year(-1)). Patients receiving bypassing agents utilized 21,000,000 IU of aPCC (median consumption/patient of 360,000 IU year(-1)), and 38,000 mg of rFVIIa (median consumption/patient of 440 mg year(-1)). The annual cost/patient on ITI and on bypassing agents therapy was analysed. Recombinant products represented the product of choice for children therapies in >90\% of the cases. FVIII prophylaxis of severe HA patients without inhibitor costs about half than therapy with bypassing agents and is three times less expensive than prophylaxis with such agents. Therefore, the possibility to restore FVIII prophylaxis, having eradicated the inhibitor through ITI, can justify the high costs of ITI treatment needed in the short term. Consistent with this notion, over the last years a 50\% increase in the number of patients undergoing ITI in Italy was registered.