Subcutaneous Immunoglobulin for CIDP

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune neurological disorder that causes limb weakness and numbness. Many patients require immunosuppressants and plasma exchange (PLEX) to control their symptoms. Intravenous immunoglobulin (IVIG)is also an effective treatment (Hughes et al, 2006 & 2008; Hughes, 2009; Cocito et al, 2010), and the American Academy of Neurology (AAN) guideline recommended that it should be offered in the long-term treatment of CIDP (Patwa et al, 2012). While effective, IVIG causes systemic side effects in about 5% of patients. These side effects include rash, pruritus, myalgia, fever, chills, headache, low back pain, nausea, vomiting, changes in blood pressure or heart rate, renal failure, and aseptic meningitis (Berger, 2008). For many patients who are chronically treated with IVIG, venous access may be a problem over time. An alternative is the subcutaneous (SC) route, which has been in use since 1980 for primary immune deficiency disorders and is the treatment of choice for this condition in Scandinavia and England (Radinsky et al, 2003). As compared to IV route, SC route maintains higher trough levels of immunoglobulins, increases patient independence, reduces systemic side-effects, and is better tolerated in those who are pregnant or sensitized to IgA (Radinsky et al, 2003). In a review of side effects associated with 33,168 SCIG infusions, no severe or anaphylactoid reactions occurred (Gardulf et al, 1995). Patients can self-administer medication, and hence, overall cost may be reduced. A retrospective study of 28 children with primary immunodeficiency in Canada showed that the mean difference in costs between IVIG and SCIG during the study period (1 year on IVIG and 1 year on SCIG) was $4,346 in favor of SCIG (Ducruet et al, 2011). A US$10,100 reduction in cost per year per patient associated with SCIG use was also reported by Gardulf et al (1995) in Sweden. Disadvantages of SCIG include more frequent infusions and local reactions at sites of infusion (transient swelling, soreness, redness, induration, local heat, and itching) in about 1% of patients.