The purpose of this study is to evaluate whether IMMUNATE S/D is effective and safe in the treatment of hemophilia A patients. The study consists of 3 parts: Part 1 is a pharmacokinetic comparison of IMMUNATE S/D and its predecessor IMMUNATE. Part 2 is an evaluation of efficacy and safety of IMMUNATE S/D. Part 3 is a pharmacokinetic study of IMMUNATE S/D.