Revisiting the cost-effectiveness of primary prophylaxis with clotting factor for the treatment of severe haemophilia A

Summary.  Severe haemophilia A is a lifelong condition that requires treatment with exogenous clotting factor. While primary prophylaxis is the clinically preferred method of delivering treatment, its provision is costly. A 2002 evaluation of primary prophylaxis suggested an incremental cost-effectiveness of approximately £50 000 per additional quality-adjusted life-year (QALY). However, since this time, preferable evaluative methods have been developed and means of assessing the value of future research also now exist. Thus, the primary aims of this study were to update a previously published cost-effectiveness analysis of primary prophylaxis vs. treating on-demand in terms of methods and to estimate the value of undertaking further primary research. The base case incremental cost-effectiveness ratio was shown to be approximately £37 000, £10 000 lower than the value published in 2002. The main reason for this difference was the use of different structural assumptions and methods to fit the various model parameters. At a willingness to pay per additional QALY threshold of £30 000, the probability prophylaxis is cost-effective was 13%. However, this increased to over 90% when alternative structural assumptions were employed, such as the rate at which future QALYs are discounted. The value of further research to increase the precision of this newly calculated cost-effectiveness estimate was high at a threshold willingness to pay values of £30 000–£40 000 per QALY, particularly for the utilities associated with the health states. Thus, there is considerable value in conducting further primary research related to economic aspects of primary prophylaxis.