Immunoglobulin (Ig), an antibody found in the plasma portion of the blood, is used for the treatment of multiple disease states. According to a virtual session at the National Association of Specialty Pharmacy (NASP) Annual Meeting and Expo 2020, there are important considerations to account for when choosing the appropriate therapy for each patient based on their specific needs.

​During a session on the state of Ig care in 2020, Allan Tsao, RPh, DPh, infusion program director​ at US Bioservices​, explained that the FDA has currently approved Ig for treating diseases such as chronic lymphocytic leukemia (CLL), chronic B cell lymphocytic leukemia​, common variable immunodeficiency, chronic inflammatory demyelinating polyneuropathy​, immune-mediated thrombocytopenia, idiopathic thrombocytopenia purpura​, Kawasaki disease, pediatric HIV type 1 infection​, and multifocal motor neuropathy​.

When treating these diseases, Ig is effective because of its ability to be used by the immune system to neutralize pathogens, such as pathogenic bacteria, fungi, and viruses​. There are also different subclasses of Ig that are classified into IgA, IgD, IgE, IgG, and IgM​. Among these, IgG also has 4 subclasses that are named in order of increasing abundance at IgG1, IgG2, IgG3, and IgG4.

There are 2 main approaches used by providers for Ig treatment for different disease types, according to Tsao. For immunodeficiencies, replacement therapy is used because in these cases, the body is producing insufficient or non-functioning immunoglobulins. This occurs most commonly because of the presence of other conditions, such as CLL or following a bone marrow transplant. In these situations, replacement therapy allows the body to more effectively fight infections.

In cases of autoimmune disorders, immunomodulation therapy is used due its multiple complex and complementary mechanisms of actions​. According to Tsao, this therapy type allows for the neutralization of pathogenic autoantibodies by anti-idiotypic antibodies​, as well as the down regulation of antibody production​. This then allows for the suppression of pathogenic cytokine and the inhibition of super-antigens​.

Additionally, there are some non-FDA indicated uses for these therapies that are commonly used by providers. Tsao explained that Ig is commonly used for neonatal alloimmune thrombocytopenia, myasthenia gravis, Guillain-Barre syndrome, stiff-person syndrome,​ pemphigus, pemphigoid, polymyositis, dermatomyositis, immune-mediated necrotizing myopathy, and pre or post organ transplants.

Tsao noted that despite Ig not being indicated by the FDA for use before or after an organ transplant, Ig is able to lower the level of human leukocyte antigen antibodies, which hinders their ability to attack the transplanted organ​. This ability of Ig makes it a valuable component in treating a patient so that they can experience successful outcomes following an organ transplant, according to Tsao.

Despite the potential for successful patient outcomes following treatment with Ig, there are still issues to consider related to patients’ quotidian lives, as Ig is often a lifelong treatment commitment. This makes the decision between intravenous immunoglobulin (IVIg) and subcutaneous immunoglobulin (SCIg) infusions critical for patients in how often they will need to receive treatment.

“For IVIg, the frequency is a little bit less at about once a month or every 3 to 4 weeks, as opposed to SCIg, where you need to be [giving treatments] a little bit longer and a little more frequently—sometimes every few days,” Tsao said. “However, on the Ig level, [with IVIg] you get a little bit of a higher spark and a lower trough, and also you have the wearing off effect between infusions because the duration of the infusion is usually a bit longer, maybe once a month, as opposed to a more consistent level on the SCIg, as it’s being used more frequently. [With SCIg] once the Ig level reaches a steady state, it is usually pretty stable throughout.”

Tsao additionally explained that with IVIg, there are some common systemic adverse effects (AEs) for patients, but that local reactions to treatment are uncommon. However, with SCIg, systemic AEs are rare whereas local reactions are common. To manage the AEs associated with IVIg, pre-medication is commonly used. Contrarily, pre-medication is less necessary for SCIg.

Additionally, Tsao noted that the cost of therapy is something to consider for patients, as IVIg has a higher associated cost due to the need for nursing support, whereas SCIg has lower associated costs due to it being possible for patients to self-administer the infusion.

“Obviously, with needing nursing support to do the infusion [for IVIg], you have that consideration there. For SCIg, when the patient is taught and trained how to provide self-infusion, then the cost of therapy is basically down to the drug and the supply itself,” Tsao said.

Tsao explained further that when considering the choice between IVIg and SCIg, although both infusions are well-tolerated by patients, independence is not achievable for patients with IVIg infusions. Although this may make clinical monitoring easier for providers, it will have other effects on the lives of patients.

“Clinical monitoring, from my perspective, will probably be easier when you have a nurse or nursing agency that could report consistently on how things are going, as opposed to SCIg patients, which will have to depend on the patient to provide updates on how they’re doing,” Tsao said.

With SCIg, independence is possible due to patients’ ability to self-administer the infusion following proper training. Although this can make clinical monitoring potentially more difficult for providers depending on the patient, it may be a benefit for patients’ lives, as they are able to have more independence and flexibility around their treatments.

REFERENCE
Sheets J, Tsao A. State of Care 2020: Immunoglobulin. Presented at: NASP Annual Meeting & Expo 2020; September 16, 2020; virtual. nasp.6connex.com/event/VirtualExperience/en-us#!/Lobby. Accessed September 16, 2020.