Subcutaneous Immunoglobulin Substitution in Ig-Naive Patients with PID – Available Efficacy and Safety Data
The prevalence of primary immunodeficiencies (PID) is estimated at 1:10,000. Below, we summarize the available findings on the efficacy and safety of subcutaneous immunoglobulin substitution in Ig-naive patients (i.e., without prior immunoglobulin substitution).
Evaluated Studies
From the MEDLINE, Embase, BioSciences Information Service and Cochrane Library databases, 16 studies assessing the efficacy, safety, quality of life, and dosing regimen of subcutaneous immunoglobulin replacement therapy (SCIG) in Ig-naive patients with PID were selected. This included 1 prospective single-arm study, 14 retrospective cohort studies, and 1 cross-sectional study with 14 to 15,327 subjects. In 5 and 2 studies, respectively, only adult or only pediatric patients were involved.
Findings
Seven studies provided SCIG dosing regimens. The most common regimen included an initial dose of 100 mg/kg under physician supervision, followed by 100 mg/kg once weekly at home. In another study, the average Ig dose was 160 mg/kg per week or 400 mg/kg every 4 weeks.
Three parameters were monitored to evaluate SCIG efficacy – IgG levels, infection incidence, and the need for antibiotic therapy:
- IgG levels were examined in 8 studies. The average IgG level before starting SCIG therapy in Ig-naive patients ranged from 1.7 to 6.6 g/l, and in previously intravenously substituted patients reached up to 8.5 g/l. In one evaluated study, the level increased to 11.3 and 11.8 g/l after 12 months of therapy.
- Infection incidence was addressed in 4 studies, and a significant reduction was observed during SCIG therapy – for instance, in one study (n = 18) from 4.73 to 3.95 per year in Ig-naive patients, and in another (n = 102) from 3.69 to 0.52 per year.
- A total of 6 studies also examined the need for antibiotic therapy, which was significantly reduced in both Ig-naive patients and those previously treated with intravenous immunoglobulin (IVIG).
SCIG safety was evaluated in 5 studies. Adverse events were mild to moderate, even in Ig-naive patients, mostly involving injection site reactions such as erythema, swelling, tenderness, or local discomfort.
Quality of life was examined in 3 studies, showing improvement in multiple domains according to the SF-36 questionnaire several months after starting SCIG therapy in a higher proportion of patients compared to those who began IVIG therapy.
Conclusion
So far, only a limited number of studies have been published on the efficacy and safety of SCIG in Ig-naive patients. Data from available studies suggest that clinical outcomes in these patients are favorably comparable to those in patients on intravenous immunoglobulin therapy.
(mafi)
Source: Anderson-Smits C., Park M., Bell J. et al. Subcutaneous immunoglobulin use in immunoglobulin-naive patients with primary immunodeficiency: a systematic review. Immunotherapy 2022; 14 (5): 373–387, doi: 10.2217/imt-2021-0265.
Did you like this article? Would you like to comment on it? Write to us. We are interested in your opinion. We will not publish it, but we will gladly answer you.
