Enzyme Facilitated Immunoglobulin Infusions

Those with immune deficiencies are physiologically unable to produce adequate amounts of antibodies to provide protection against various infections. The infused immunoglobulin acts as the patient’s own Ig would act, if produced, but does not stimulate new production of antibodies, so it must be administered at regular intervals to maintain protective levels. The exact mechanisms of action, when used to treat autoimmune diseases, are unknown, although there are numerous theories and probably just as numerous various mechanisms of action. Additionally, different mechanisms may be responsible for the product’s effectiveness for different conditions. Approximately 20% - 30% of the gamma globulin administered is used for antibody disorders, about 10% - 20% for infectious disorders, and the rest for autoimmune and inflammatory disorders, some of which are off label indications, meaning not specifically approved by the FDA.

Ig is administered either intravenously (IVIg) or subcutaneously (SCIg). The first subcutaneous Ig infusion was performed in 1952 by a Colonel Ogden Bruton, on an 8 year old boy with recurrent sinopulmonary infections.  The standard administration up until this time was weekly intramuscular injections, however, they were poorly tolerated by most patients due to the discomfort that accompanied the treatments. 

With any type of subcutaneous infusion we are limited with the amount of fluid volume that may be delivered.  The subcutaneous tissue can effectively absorb and disperse a limited amount of fluid volume. Hyaluronidase has been used in clinical settings for over 50 years to facilitate the delivery of SC fluids and medications, and were derived from bovine and ovine sources.   The hyaluronidase enzyme temporarily degrades the hyaluronan, a structural component of the subcutaneous space that is just beneath the outside surface of the skin. This temporary degradation created by the injected enzyme creates an improved subcutaneous absorption and dispersal of biological drugs containing large therapeutic molecules as well as medications containing small molecules and fluids.  With traditional infusions of subcutaneous Ig we were typically limited to a volume of 20-40 mls. The recent development of a recombinant human hyaluronidase is enhancing the SCIg delivery method increasing absorption and bioavailability, with this method being referred to as hyaluronidase facilitated subcutaneous immunoglobulin therapy (fSCIg). With the addition of hyaluronidase the Ig volumes that may be administered subcutaneously can increase to up to 700 mls. In addition the bioavailability is increased significantly with SCIg at 67% and fSCIg at 92%.

Ig administered by the SC route effectively decreases some of the systemic side effects seen with intravenous administration of immunoglobulin. Typically IVIg is well tolerated but some patients do experience rate related side effects that include flu-like symptoms, muscle ache, low-back pain, headache and tiredness. Rarely more severe side effects such as anaphylaxis, aseptic meningitis, thrombosis and renal failure could occur.

The development of the new recombinant human hyaluronidase facilitated immunoglobulin administration will change immunoglobulin doses, amounts, bioavailability and frequency of Ig administrations.   All healthcare providers: physicians, pharmacists, and nurses should become familiar with this new method of immunoglobulin administration.

News Article by Capra Dalton RN

References:

Hyaluronidase facilitated subcutaneous immunoglobulin in primary immunodeficiency
http://www.dovepress.com/hyaluronidase-facilitated-subcutaneous-immunoglobulin-in-primary-immun-peer-reviewed-article-ITT

Subcutaneous immunoglobulin replacement therapy in the treatment of patients with primary immunodeficiency disease
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2817783/

Halozyme Therapeutics
http://www.halozyme.com/Technology/Enhanze-Technology/default.aspx