Methods: Following a 3-month IGIV treatment period, patients received IGHy every 3 to 4 weeks for ~18 months, followed by up to an additional 21 months.
Results: Of the 63 enrolled patients aged ≥16 (range 16–78) years, 61 were administered IGHy for up to ~3.5 years at the established dose. Rates of validated acute serious bacterial infections (VASBIs) and all infections were 0.01/patient-year (upper limit of 99% confidence interval [CI]: 0.01) and 3.05/patient-year (95% CI: 2.63–3.52), respectively. For the subset of patients completing IGHy through the extension study (n=37), the infection rate/patient-year (3.18 overall) remained relatively constant (3.14 for months 1–12; 3.60 for months 12–24; and 2.70 for months 25–33.6). Over the course of IGHy treatment, serum trough levels of antibodies to Haemophilus influenza, Clostridium tetani toxoid, and hepatitis B virus were protective.
Conclusions: In patients aged ≥16 years who were treated with IGHy for up to ~3.5 years, efficacy remained constant over time.