Preliminary data from clinical trials suggest that this may result in extension of the half-life from around 3 h to 16 h. A more potent rVIIa analogue has also been developed in which three specific amino substitutions (V158D/E296V/M298Q) stabilize the molecule in its active conformation without tissue factor, resulting in increased activity on the surface of activated platelets. In vitro data suggest that this novel agent has a faster onset of action as well as enhanced clot strength and stability. Recombinant porcine factor VIII is likely to become available in the next few years. The rationale for its use is based on the fact that the structure of the porcine factor VIII is sufficiently

similar to that of human factor VIII to possess coagulant activity but yet also sufficiently different to have low binding affinity to the circulating anti-human factor VIII inhibitory alloantibody. Both FEIBA and recombinant activated factor VII HDAC inhibitor AZD6244 concentration (Novoseven) may be used to cover surgical procedures in haemophilia patients with inhibitors. The published data suggest comparable safety and efficacy [7–10]. The previous clinical response to treatment should be considered. There should be a documented good response to the product chosen for the patient. The challenges posed by undertaking elective orthopaedic

surgery in patients with haemophilia complicated by inhibitors are still formidable and should not be underestimated. Such operations should only be undertaken

in comprehensive care centres, which have the requisite multidisciplinary experience and facilities. Consideration also needs to be given to a number of practical points such as timing and staffing levels when planning elective procedures [10]. Surgery should ideally be scheduled for the morning of a day early in the week. Pre-operative assessment of haemostasis should include assaying of the anti-factor VIII antibody titre as well as the platelet count, and prothrombin time should be checked. Levels of other coagulation factors may be assayed if there is evidence of significant impairment of liver function. Medication should be reviewed to ensure that non-steroidal anti-inflammatory drugs are not used in the peri-operative period. There selleck products are no currently validated laboratory methods for monitoring treatment with either FEIBA or rVIIa, although a number of groups are evaluating thromboelastography and thrombin generation tests in this setting. The overall cost of products to cover this type of surgery is often very high. However, it must be borne in mind that the costs may be recovered over subsequent years through abolition of further bleeding episodes within the joint. N. Goddard We are aware that between 10% and 30% of patients affected with haemophilia A subsequently go on to develop inhibitors to factor VIII, the incidence being between 2% and 5% in haemophilia B.