Immunate Solvent Detergent (S/D) is a plasma derived, purified, human factor VIII (FVIII) - von Willebrand factor (VWF) complex subjected to two virus inactivation/removal processes: S/D and vapor heat treatment. This prospective, multicentre, three-part clinical study evaluated the pharmacokinetics (in comparison to the predecessor product Immunate), efficacy and safety of Immunate S/D in 56 previously treated patients with severe haemophilia A. Subjects received Immunate S/D on-demand, as a prophylactic regimen or both. The results of the pharmacokinetic population demonstrate that Immunate and Immunate S/D were equivalent with respect to the FVIII - and to the retrospectively VWF - parameters assessed. A total of 623 bleeding episodes were reported in 47/56 subjects. The duration of prophylaxis ranged from 0.1-5.2 months with a total of 175.6 months. The median number of bleeds per month in subjects on prophylaxis was 0 (range 0-10). Ninety-six percent of bleeding episodes were rated as having an excellent or good response. For most bleeding episodes (89%), subjects required only one infusion with a mean dose of 29.6 IU kg(-1). No FVIII inhibitory antibodies were observed in any subject. No related serious adverse events were reported. Thus, the introduction of S/D treatment did not alter the PK characteristics and function of VWF and FVIII molecules of Immunate S/D which is effective and safe for treatment of bleeding episodes, management of surgical procedures, and prophylaxis.