Factor VIII concentrate for hemophilia: comparison of two heat-treated products

In a controlled trial of heat-treated factor VIII concentrate from Cutter Laboratories and from Connaught Laboratories Limited, 25 patients with hemophilia received Cutter factor VIII and 24 patients with hemophilia received Connaught factor VIII. The mean increase in factor VIII level was similar for the two products (1.88% and 1.98% per unit/kg of body weight respectively [p greater than 0.1], or 89% and 95% respectively of the expected increase [p greater than 0.1]). In-vivo survival (the duration of factor VIII in the circulation) was compared after seven infusions of each product. The mean half-disappearance times were 10.7 and 9.1 hours respectively (p = 0.1), and the mean biologic half-lives were 11.6 and 9.9 hours respectively (p = 0.04); the clinical significance of the latter difference is dubious. Both products could be reconstituted satisfactorily from the dried state. Two subjects experienced relatively minor side effects following infusion of one lot of Cutter factor VIII. Individual responses to both products showed considerable variation. Therefore, when it is critical to attain predetermined levels of factor VIII, such as before and after surgery, factor VIII assays should be performed to check the patient's response.