Long-Term Tolerability, Safety, and Efficacy of Recombinant Human Hyaluronidase-Facilitated Subcutaneous Infusion of Human Immunoglobulin for Primary Immunodeficiency.

PURPOSE: Treatment of primary immunodeficiency diseases (PIDD) with subcutaneous (SC) infusions of IgG preceded by injection of recombinant human hyaluronidase (rHuPH20) (IGHy) to increase SC tissue permeability was evaluated in two consecutive, prospective, non-controlled, multi-center studies. METHODS: Subjects >4 years of age received SC IgG replacement at a weekly dose equivalent of 108 % of their previous intravenous (IV) dose, facilitated by prior injection of 75 U/g IgG of rHuPH20. Starting with weekly SC infusions, the interval was increased (ramped-up) to a 3- or 4-week schedule. RESULTS: Eighty-three subjects (24 < 18 years; 59 ≥ 18 years) received 2729 infusions (excluding ramp-up) at a mean dose of 0.155 g/kg/week in the pivotal and 0.156 g/kg/week in the extension study. IGHy exposure exceeded 30 months in 48 subjects. During 187.7 subject-years of IGHy exposure, 2005 adverse events (AEs) (10.68 per subject-year) occurred. The rate of related systemic AEs during consecutive 1-year periods remained low; the rate of related local AEs decreased from 3.68/subject-year in months 1-12 to approximately 1.50/subject-year after 30 months of treatment. Fifteen subjects transiently developed anti-rHuPH20 binding antibody. There was no difference in AE rates in these subjects before and after the first titer increase to ≥1:160. The rate of infections during IGHy exposure was 2.99 per subject-year and did not increase during the studies. Annual infection rates were 3.02 in subjects <18 years and 2.98 in subjects ≥18 years. CONCLUSIONS: Long-term replacement therapy with IGHy was safe and effective in 83 pediatric and adult subjects with PIDD.

Clinical Practice Experience with HyQvia in Adults Using Alternative Dosing Regimens and Pediatric Patients: A Retrospective Study.

INTRODUCTION: HyQvia (Immune Globulin Infusion 10% [Human] with Recombinant Human Hyaluronidase) was developed to combine the advantages of intravenous and subcutaneous immune globulin (SCIG), allowing administration of larger volumes at a single subcutaneous site with less frequent dosing when compared to other SCIG products. Current US prescribing guidelines for HyQvia are limited to adults and do not encompass the flexibility required to achieve success in all patients with primary immunodeficiency (PID). METHODS: This retrospective study was designed to evaluate the clinical experience of treating patients with PID with HyQvia regimens outside of package insert recommendations as well as in pediatric patients. Data were abstracted from 38 patient records (317 HyQvia infusions), including five patients less than 16 years of age, from seven US immunology clinics. RESULTS: Among 37 patients receiving HyQvia regimens differing from prescribing guidelines, the most notable variations included shorter ramp-up periods, use of two rather than one infusion site, and slower than maximal infusion rates to mitigate local adverse events (AEs). The medication volume infused for single site doses ranged from 75 to 200 mL and doses split between two sites ranged from 100 to 750 mL. The most common type of regimen variation was a condensed ramp-up phase (shorter schedule, higher doses), and 96% (24/25) of patients managed in this way completed ramp-up. The most common ramp-up schedule was three infusions (one at 25-45%, another at 50-75%, and the final at 100% of target dose) spread over 2-4 weeks. CONCLUSIONS: A shorter ramp-up schedule did not appear to increase the number of AEs compared to standard ramp-up schedules. For patients with AEs, slower infusion rates and the use of two sites may improve medication tolerability. Four of five pediatric patients reported no AEs, and only one discontinued, stating a fear of needles. HyQvia may be tailored to adults requiring alternative rates, ramp-up, and/or dosing regimens and may be especially well-suited to children.