Treatment of primary immunodeficiency with Kiovig: a literature review

Correlations Among Subcutaneous Immunoglobulin Dosage, Immunoglobulin G Serum Pre-infusional Levels and Body Mass Index in Primary Antibody Deficiency Patients: A Pooled Analysis from the SHIFT/IBIS Studies

Background and Objective

In recent years, two Italian non-interventional studies evaluated subcutaneous immunoglobulin (SCIG) treatment in patients affected by primary antibody deficiency (PAD). The SHIFT study considered patients who were treated with intravenous immunoglobulin (IVIG) or SCIG 16% (Vivaglobin^®) and then replaced this therapy with weekly treatments of SCIG 20% (Hizentra^®). The IBIS study evaluated patients previously taking a weekly SCIG 20% regimen, who instead began therapy with biweekly SCIG 20% to assess the correlation between the dose of immunoglobulin G (IgG) administered and the body mass index (BMI) of patients, determine if there is a need for dosage adjustments on a BMI basis, and identify the predictors of serum IgG trough levels in our cohort.

Methods

In this study, we analyzed the pooled data of 109 PAD patients enrolled in the SHIFT and IBIS studies. Only prospective phases were considered.

Results

The total monthly SCIG dose showed comparable trends among weight categories, except for underweight patients. When we considered the monthly SCIG dosage per kilogram of body weight, a significant decreasing trend according to BMI was observed. Data on IgG trough levels were available for 88 patients, with a mean IgG serum level of 8.4 ± 1.6 g/L. A stepwise regression model revealed that the mean monthly dosage of SCIG 20% (p = 0.04248) and the mean monthly dosage of IgG per kilogram of body weight were the only two independent predictors associated with IgG trough levels. No association was found between BMI and IgG trough levels.

Conclusions

These findings support the concept that the cumulative monthly dose of SCIG and the dose of SCIG per kilogram of body weight affect IgG trough levels in PAD patients, irrespective of BMI.

Economic burden of common variable immunodeficiency: annual cost of disease

OBJECTIVES

In the context of the unknown economic burden imposed by primary immunodeficiency diseases, in this study, we sought to calculate the costs associated with the most prevalent symptomatic disease, common variable immunodeficiency (CVID).

METHODS

Direct, indirect and intangible costs were recorded for diagnosed CVID patients. Hidden Markov model was used to evaluate different disease-related factors and Monte Carlo method for estimation of uncertainty intervals.

RESULTS

The total estimated cost of diagnosed CVID is US$274,200/patient annually and early diagnosis of the disease can save US$6500. Hospital admission cost (US$25,000/patient) accounts for the most important expenditure parameter before diagnosis, but medication cost (US$40,600/patients) was the main factor after diagnosis primarily due to monthly administration of immunoglobulin.

CONCLUSION

The greatest cost-determining factor in our study was the cost of treatment, spent mostly on immunoglobulin replacement therapy of the patients. It was also observed that CVID patients' costs are reduced after diagnosis due to appropriate management.