Individualizing Therapy in CIDP: A Mini-Review Comparing the Pharmacokinetics of Ig With SCIg and IVIg.

Immunoglobulin (Ig) therapy is a first-line treatment for CIDP, which can be administered intravenously (IVIg) or subcutaneously (SCIg) and is often required long term. The differences between these modes of administration and how they can affect dosing strategies and treatment optimization need to be understood. In general, the efficacy of IVIg and SCIg appear comparable in CIDP, but SCIg may offer some safety and quality of life advantages to some patients. The differences in pharmacokinetic (PK) profile and infusion regimens account for many of the differences between IVIg and SCIg. IVIg is administered as a large bolus every 3-4 weeks resulting in cyclic fluctuations in Ig concentration that have been linked to systemic adverse events (AEs) (potentially caused by high Ig levels) and end of dose "wear-off" effects (potentially caused by low Ig concentration). SCIg is administered as a smaller weekly, or twice weekly, volume resulting in near steady-state Ig levels that have been linked to continuously maintained function and reduced systemic AEs, but an increase in local reactions at the infusion site. The reduced frequency of systemic AEs observed with SCIg is likely related to the avoidance of high Ig concentrations. Some small studies in immune-mediated neuropathies have focused on serum Ig data to evaluate its potential use as a biomarker to aid clinical decision-making. Analyzing dose data may help understand how establishing and monitoring patients' Ig concentration could aid dose optimization and the transition from IVIg to SCIg therapy.

Prefilled syringes for immunoglobulin G (IgG) replacement therapy: clinical experience from other disease settings.

INTRODUCTION: Ready-to-use prefilled syringes for drug delivery are increasingly used across a broad spectrum of clinical specialties. For patients with primary immunodeficiencies manifesting as antibody deficiencies, immunoglobulin G (IgG) replacement therapy (IgRT) by subcutaneous administration is an established treatment modality. Expanding IgRT administration options through the introduction of prefilled syringes may further improve its utility. AREAS COVERED: Here, we collate experience with prefilled syringes from other clinical settings to inform on their practicality and suitability for IgRT. In addition to discussing drug characteristics such as stability, pharmacokinetics, and efficacy, we focus on treatment delivery, physician/patient experience, costs, and the importance of education for the use of prefilled syringes. EXPERT OPINION: Perceived benefits of prefilled syringes include accurate dosing, sterility, and reduced treatment time, while offering patients greater choice, convenience, and ease-of-use. Our review of clinical experience with prefilled syringes supports this consensus. Relatively few studies directly compare prefilled syringes with conventional administration, and robust studies of cost-effectiveness and health-related quality of life are needed on a drug-by-drug basis. Growth in the availability of prefilled syringes will continue, encouraged by the importance of patient choice and treatment convenience, toward the goal of individualized treatment regimens and improved quality of life.

Home therapy with subcutaneous immunoglobulins for patients with primary immunodeficiency diseases.

The most frequently encountered patients with primary immunodeficiency disease (PID) are those with antibody deficiencies. These patients require life-long immunoglobulin (IgG) replacement therapy to prevent severe and reoccurring infections. IgG is traditionally administered intravenously (IVIG) on an outpatient basis, although in some Scandinavian countries subcutaneous administration of IgG (SCIG) as home self-infusion has become the predominant mode of delivery. Compared with IVIG, SCIG therapy leads to a more physiologic IgG profile since the large variations between peak and trough levels of serum IgG are blunted by slow absorption and maintenance of closer equilibrium between intra- and extravascular compartments. SCIG therapy has been shown to be as effective as IVIG in preventing infections and has a better safety profile, with fewer systemic side effects. While local tissue reactions are common with SCIG, they are usually mild, tend to improve over time and typically do not interfere with therapy. Switching to SCIG therapy from IVIG can lead to significant improvements in health-related quality of life, appears to be more convenient for the patient, and can make it easier for the patient to travel. In those patients with difficult vascular access and intolerable side-effects with IVIG therapy, SCIG therapy may be the only treatment option. Selected patients can be expected to benefit greatly from SCIG therapy, although implementation of a successful home-treatment program requires proper education, training, and supportive care.