Patient and parent preferences for haemophilia A treatments.

Little is known about the relative importance of factor VIII (FVIII) treatment attributes to haemophilia A patients and their willingness to accept trade-offs among these attributes. To quantify patient and parent preferences for FVIII treatments and compare the relative importance of treatment attributes. Adult patients and parents of children with severe haemophilia A in the US completed a web-enabled, choice-format conjoint survey that presented a series of 12 trade-off questions, each including a pair of hypothetical treatment profiles. Each profile was defined by percent of bleeds stopped with one or two infusions, chance of developing an inhibitor, risk of viral infection, preparation volume, dosage strengths available, and history of supply shortage. Trade-off questions were based on a D-optimal experimental design. Preference weights for attribute levels were estimated using random-parameters logit. One hundred and forty seven subjects completed the survey. Over the ranges of attribute levels included in the study, risk of viral infection was the most important attribute. Remaining attributes were ranked in decreasing order of importance as follows: chance of developing an inhibitor, dosage strengths available, percent of bleeds stopped with one or two infusions, history of supply shortage, and preparation volume. Risk of viral infection was 6.0 times as important as percent of bleeds stopped with one or two infusions and 2.7 times as important as the chance of developing an inhibitor. While risk of viral infection was the most important attribute, this research demonstrates that many FVIII treatment attributes are important in the decision-making process.