Turoctocog alfa pegol (N8-GP) in severe hemophilia A: Long-term safety and efficacy in previously treated patients of all ages in the pathfinder8 study.

Background: N8-GP (turoctocog alfa pegol; Esperoct) is a glycoPEGylated human recombinant factor VIII (FVIII).

Objectives: Pathfinder8 (NCT01480180) was a phase 3, multinational, open-label, nonrandomized trial to investigate the long-term safety and efficacy of N8-GP in people of all ages with severe hemophilia A previously treated with N8-GP.

Patients/method: Patients were recruited from the completed phase 3 pathfinder2 and pathfinder5 trials to receive intravenous N8-GP prophylaxis for up to 104 weeks, administered every 7 days, twice weekly, or three times weekly. Primary and secondary end points were the number of adverse events (AEs) reported and efficacy of treatment, respectively.

Results: Overall, 160 patients were exposed to N8-GP for a mean of 179 exposure days and 681 calendar days (≈1.9 years) per patient. In total, 119 patients experienced 510 AEs, corresponding to a rate of 1.71 AEs per patient-year of exposure; 97.5% of AEs were mild or moderate in severity, and no AEs led to withdrawal. No patients developed FVIII inhibitors during the trial. The Poisson estimate of mean annualized bleeding rate for all bleeds (excluding surgery) and across all regimens was 1.10 (median, 0.00), and for spontaneous bleeds was 0.61 (median, 0.00). Most (55.6%) patients experienced no bleeds that required FVIII treatment (excluding perioperative bleeds). The estimated hemostatic success rate for the treatment of 322 bleeding episodes (excluding surgery) was 95.8%, including missing values as failure.

Conclusions: Long-term prophylactic use of N8-GP appeared safe and efficacious across all age groups in people with severe hemophilia A previously treated with N8-GP.