Bolus injection (BI) of sucrose-formulated recombinant factor VIII (rFVIII-FS) is an approved treatment for haemophilia patients undergoing major surgery. Continuous infusion (CI) during surgery has potential benefits by providing steady administration of replacement factor to the patient, avoiding high peaks and low troughs. We tested the stability of rFVIII-FS under CI conditions and conducted a single-centre, open-label, phase III study to evaluate the efficacy and safety of CI using rFVIII-FS in haemophilia A patients undergoing surgery. Patients received bolus rFVIII-FS to achieve >or=80% FVIII levels 30-60 min presurgery, followed by CI of rFVIII-FS at a rate calculated to maintain haemostatic factor levels until days 8-10 post surgery. The rate of infusion was adjusted according to daily calculations derived from the actual clearance. The stability of rFVIII-FS was found to be appropriate for CI for 7 days under the same conditions as clinical settings. Fourteen patients (mean age 37.8 years) receiving on-demand FVIII treatment without a history of inhibitors underwent 15 surgical procedures including joint replacements, synovectomies, multiple tooth extractions, and cholecystectomy. Bleeding was similar to that observed in non-haemophilia patients undergoing similar operations in the same department. Haemostasis during surgery was considered by the attending surgeons as 'excellent' or 'good' in all cases; study investigators rated all 15 cases as 'excellent' overall. There were no adverse events, including inhibitor formation, related to rFVIII-FS. rFVIII-FS was found to be suitable for use in CI in haemophilia A patients undergoing major surgery.