OBJECTIVES: The objective of this analysis was to understand the economic consequences of different products in primary prophylaxis in severe Haemophilia A patients. Miners’ (2002, 2009) haemophilia economic Markov model was revised to compare two different factor VIII products - a full-length recombinant FVIII (Advate) and a B domain-deleted recombinant FVIII (BDDrFVIII) (Refacto AF). Based on documented differences in half life in a pharmacokinetic cross-over license study [1] with results submitted to EMA[2], this research evaluated the amount of clotting factor required to maintain the patient factor VIII trough levels above 1%. If a product has a shorter half-life, more clotting factor is required to prevent factor VIII levels falling below the minimum trough level. METHODS: The same basic model structure of Miners’ haemophilia economic Markov model was used to analyse the effects of differences in half-life in an Italian economic country setting, full-length recombinant FVIII (Advate) half-life 13.3 hours at a list price of €0.75 per IU versus BDDrFVIII (Refacto AF) half-life 11.2 hours at a list price of €0.69 per IU. The model considers the amount of factor required to prevent trough clotting factor levels from falling below 1%. RESULTS: The analysis estimated that the mean expected, discounted lifetime (70 years) cost of primary prophylaxis in a severe Haemophilia A patient was €0.88 million less using full length recombinant FVIII (Advate) when compared to a BDDrFVIII (Refacto AF), assuming a 2.1 hour shorter half-life; i.e. equal to over €12,500 in cost savings per patient per year. CONCLUSIONS: This analysis shows that prophylaxis therapy using full-length recombinant FVIII (Advate) may be cost saving compared to BDDrFVIII (Refacto AF) based on the difference in half-life reported, even if BDDrFVIII has a lower price per IU. [1] Recht et al. Haemophilia 2009:1-12; [2] EMA Assessment report Refacto AF. London March 2009. http://www.ema.europa.eu/humandocs/PDFs/EPAR/Refacto/refactoaf-H-232-II-59-68-AR.pdf