Efficacy of Recombinant Human Hyaluronidase-Facilitated Subcutaneous Infusion of Immunoglobulin G (IgG) (IGHy) in Patients with Primary Immunodeficiency Disease (PIDD): Infections over Time
Monday, March 7, 2016
South Exhibit Hall H (Convention Center)
Richard L. Wasserman, MD PhD FAAAAI, Mark R. Stein, MD FAAAAI, Lisa J. Kobrynski, MD MPH FAAAAI, Sudhir Gupta, MD, PhD, FAAAAI, J. Andrew Grant, MD, FAAAAI, Arye Rubinstein, MD, FAAAAI, Christopher J. Rabbat, PhD, Werner Engl, PhD, Barbara McCoy, PhD, Heinz Leibl, PhD, Leman Yel, MD, FAAAAI
Rationale: IGHy provides protection against infections at similar doses and dosing intervals as intravenous IgG (IGIV). We report IGHy efficacy over time in patients with PIDD aged ≥16 years treated for up to ~3.5 years in the IGHy pivotal phase 3 study and its extension.

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.