Activated prothrombin complex concentrate (aPCC) and recombinant activated factor VII (rFVIIa) are the only two drugs that are available to treat bleeds in haemophilia A patients with high titer inhibitors. However, management of bleeds in these patients can be challenging due to variation in response and lack of standardized methods to monitor the effect. We hypothesized that significant increase in whole blood clot stability could be achieved when tranexamic acid was given concomitantly with bypassing-agents while thrombin generation remains unaffected. In this prospective crossover study the effect of aPCC and rFVIIa with and without TXA on clot stability and thrombin generation capacity (ETP) were studied, using thromboelastography (ROTEM) and thrombin generation assay (TGA), respectively. In addition, the risk of thrombosis and disseminated intravascular coagulation (DIC) was assessed.

Patients receive the first day aPCC (75IU/kg) and aPCC in addition to TXA (20mg/kg orally) the second day. After a 14 days washout period they crosse over using rFVIIa (90 µg/kg) otherwise the same experimental setup. Blood sampling is performed at baseline, 15, 30, 60, 120, 180 and 240 minutes post-treatment.

Inclusion Criteria:

• Haemophilia patients with high titer inhibitors or high-responding inhibitors, aged between 18-65 and no history of aspirin or NSAID use within the last 14 days were eligible for the study.

Exclusion Criteria:

• Patients with renal failure, liver disease, infected with immune deficiency virus (HIV), platelet count <150x109/L, acquired haemophilia, ongoing bleeding, hypersensitivity to TXA or a history of arterial or venous thrombosis were excluded from the study.