Patients with moderate to severe hemophilia A who switched from a prior factor VIII (FVIII) therapy to weekly prophylactic dosing regimens of octocog alfa (BAY 81-8973) experienced a smooth transition, with stable bleeding rates and no safety issues reported.

The 2-year, phase 4, multinational, open-label, prospective, noninterventional, single-arm, real-world TAURUS study (NCT02830477) included male patients of any age with moderate to severe hemophilia A. The study was carried out at 25 locations across Asia, Europe, and the United States. Results of the analysis were published recently in the European Journal of Haematology.

TAURUS was intended to primarily explore weekly prophylactic dosing regimens used in standard daily practice. Annualized bleeding rates (ABRs), treatment satisfaction and adherence, and safety were evaluated as well.

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The primary outcome measure of TAURUS was the proportion of participants receiving prophylaxis 2 or 3 times weekly at the end of the observation period. The secondary outcome measures included: (1) ABRs (joint); (2) prophylactic dosing according to age group and country; (3) change in prophylactic dosing frequency and reason for change; (4) total annualized FVIII consumption; (5) adverse events; and (6) treatment satisfaction/treatment adherence.

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All study participants were monitored closely at each study visit for adverse events, serious adverse events, and treatment-emergent adverse events. Duration, severity, relationship to the study drug, and outcomes were all recorded.

Among the 318 enrolled patients, 302 were included in the full analysis set (FAS). The median patient age was 23.5 years (range, 14.0 to 39.0 years). The mean age at initiation of prophylactic treatment was 13.2 years (median, 6.0 years; range, 0 to 64 years). Overall, 46.4% of participants were 2 to 18 years of age.

The results of the study showed that of the 302 patients in the FAS, 84.4% (255 of 302) maintained their baseline octocog alfa prophylactic regimen throughout the study. In all, 76.5% (231 of 302) of participants were on a twice or thrice weekly regimen at the end of the observation period (1 to 2 years).

During the observation period, ABRs, treatment satisfaction, and treatment adherence remained stable. No new or unexpected adverse events were observed; octocog alfa was well tolerated.

The investigators concluded that the findings of this study confirm and extend “clinical trial results, demonstrating effective protection from bleeds with octocog alfa prophylaxis in a real-world-setting, and no safety concerns.”


Santoro C, Fuh B, Le PQ, et al. Efficacy and safety in patients with haemophilia A switching to octocog alfa (BAY 81-8973): final results of the global real-world study, TAURUS. Eur J Haematol. Published online October 3, 2022. doi:10.1111/ejh.13876