Latest Results From The PUP-GCP Clinical Trial: A Low Inhibitor Rate In Previously Untreated Patients With Severe Hemophilia A Treated With Octanate

Octanate is a highly purified, double virus inactivated, human plasma-derived factor VIII (FVIII) concentrate with all coagulation FVIII bound to its natural stabilizer VWF in a VWF:RCo/FVIII:C ratio of approximately 0.4. Five prospective GCP studies with octanate were conducted in 77 previously treated patients (PTPs) with severe hemophilia A. None of these 77 PTPs developed an inhibitor while treated exclusively with octanate.

To assess the immunogenicity in previously untreated patients (PUPs), a prospective clinical trial has been initiated in 2000. This included 50 PUPs with severe hemophilia A for an observational period of 100 exposure days with octanate, for at least 6 months.

Patients with severe hemophilia A without previous exposure to FVIII or FVIII-containing products were enrolled. Efficacy and tolerability were assessed by a 4-point verbal rating scale. Inhibitors were assessed according to modified Bethesda method prior to treatment every 3-4 exposure days (ED 1-20), and after treatment every 10 EDs (ED 21-100), but at minimum every three months.

Two of 50 (4%) subjects developed clinically relevant inhibitor titers over the course of the study. Another two displayed inhibitors that disappeared spontaneously without change of dose or dosing interval. All inhibitors developed under on-demand treatment and before ED 50. From the 50 subjects, 42 had exceeded 50 EDs at the time of this analysis. Octanate was well-tolerated and the adverse event profile was consistent with the population studied. The hemostatic efficacy in prophylaxis and treatment of bleeding episodes was generally rated as “excellent” and no complication was reported for any surgical treatment.

Despite frequent inhibitor testing and predominant on-demand treatment, the data indicate a low overall inhibitor rate for octanate in patients who exceeded 50 exposure days (4/42) of which only 2 (4.8%) were clinically relevant.

Klukowska:Octapharma AG: Investigator Other. Jansen:Octapharma AG: Employment. Komrska:Octapharma AG: Investigator Other. Laguna:Octapharma AG: Investigator Other. Vdovin:Octapharma AG: Investigator Other. Knaub:Octapharma AG: Employment.