Interim Results of a Non-interventional Study on Efficacy and Tolerability of a VWF/FVIII Concentrate in von Willebrand's Disease

Scientific Research Question: wilate^® is a double virus inactivated VWF/FVIII concentrate with a physiological 1:1 ratio of FVIII:VWF. In 2012, a non-interventional study (NIS) was started. In this study Wilate-STATE we are aiming to confirm consistency of efficacy and safety data of wilate^® used in routine clinical practice with previous study data.

Methodology: After obtaining informed consent, patients with hereditary or acquired VWD of any age requiring replacement therapy are eligible to be included in the study. A thorough documentation of anamnestic data is done before details of all injections for treatment of bleeding episodes, surgeries and prophylactic treatments are documented continuously. Bleeding episodes and details of surgical procedures including efficacy assessment are rated using a 4-point-rating scale according to pre-defined criteria.

Findings: Documentation of 101 patients from 9 treatment centres had been provided so far. The distribution between the different types of VWD is as follows: 62% of patients have type 1, 30% type 2, 5% type 3 and 3% acquired VWD. Of the 101 patients, 39 were previously untreated with a VWF containing product. The patient's age ranges from 8 months to 75 years, including 45.5% paediatric patients (≤ 14 years). A total of 7505 infusions were administered with a median dose per substitution of 37 IU/kg. One patient experienced an allergic reaction without sequelae.

Of the 10 patients treated on-demand, 9 spontaneous bleeding events (BEs) excluding menstrual bleeds, are reported in 5 patients. 11.1% of BEs were mild; 66.7% were moderate, and 22.2% were severe. The efficacy of treatment was rated as ‘excellent’ or ‘good’ for 100% of BEs with a median dose of 19.6 IU/kg. In the median 1 substitution was sufficient to stop the bleeding.

Of the 35 patients treated for prophylaxis, 17 of these patients had a total of 58 spontaneous BEs (117 traumatic BEs) ; 53.4% mild, 41.4% moderate and 5.2% severe. Of the spontaneous BEs that required treatment the efficacy of treatment was rated as ‘excellent’ or ‘good’ for 98% of BEs with a median dose of 37.4 IU/kg. In the median 2 substitution were sufficient to stop the bleeding.

A total of 83 surgical procedures were performed in 70 patients; 73% with type 1 VWD, 24% type 2 and 3% acquired VWD. Of the procedures, 47 were major and 36 minor. All surgeries were managed with wilate^® prophylaxis and the efficacy was rated as ‘excellent’ or ‘good’ in 95% of surgeries.

Conclusions: The final results of this non-interventional study indicate that wilate^® is well tolerated and effective for on-demand treatment, prophylaxis, and surgical prophylaxis in patients with all types of VWD and of all ages treated as part of routine clinical practice. The data are consistent with those from previous clinical studies and provide real-life evidence on the use of wilate^® for management of VWD in all clinical settings.

No conflict of interest has been declared by the author(s).