Product Integrity & Control
When it comes to allergy immunotherapy products there are large bodies of research and information. Unfortunately, much of the information about products is confusing and even misleading. In many cases, studies and information have been used as marketing tools rather than teaching tools. The end goal to make certain brands and products appear distinct or superior from their competitors. This simply is not the case; the similarities between all allergy immunotherapy products far outweigh any differences. If there was a meaningful difference, a patent would exist and a company would be enjoying a monopoly! In general immunotherapy products are better understood as a generic pharmaceutical.
Liquid allergen extracts used in testing and treatment (SCIT & SLIT) are solutions containing dissolved allergenic proteins from pollens, dust mites, animal dander, moulds, and insects. The manufacturing process generally involves crushing these raw materials and extracting allergenic proteins by adding solvents that release them from the solid raw material into the liquid solvent. It is these allergenic proteins that are the active ingredients in the products.
This extracting process is followed by several purification steps that result in the final bulk allergen product. This product is then diluted to varying degrees to serve its function as a testing antigen, injection treatment product, or sublingual treatment product. Commonly used diluents are: Glycerin (e.g., 50% glycerin + phenol), Phenol saline (e.g., 0.4% phenol, saline), and HSA (e.g., HSA, 0.4% phenol, saline). Each diluent has strengths and weaknesses that influence extract potency, preservation, sterility, and stability.
Wherever in the world allergy products are made this extracting and diluting process is extremely similar. Studies have shown that extracts produced in the USA are more homogenous with respect to total allergenic potency than extracts produced in Europe. However, the main difference between products from Europe and North America are government regulation and labelling requirements.
In Europe, there is no consistent regulatory body that enforces units of measurement and potency when manufacturing and labelling allergy immunotherapy products.
European companies use their own ‘in house’ units of measurement to apply to their products. How measurements are determined and how the consistency between products is ensured is up to the internal controls of each particular company. As a result, there is no way to accurately compare European products against other European competitors or those from North America.
In North America all manufacturers (Brands) are governed by the same 3rd party regulations and are required to use the same units of measurement and potency when manufacturing and labelling allergen products. Health Canada and the FDA enforce these to ensure transparency and consistency in the market so doctors know what they are giving to their patients regardless of the manufacturing source.
In addition to standard units of measurement there are 19, FDA & Health Canada, standardised allergenic extracts that include the most common allergens used in treatment sets. These standards place an even higher burden of quality control and disclosure on top of the labelling requirement previously mentioned.
Beyond the differences in regulatory and labelling, the complexity and variation of allergens and their constituent proteins is a subject unto itself. The differences are intriguing from a research perspective and are important, but from a conventional clinical practice perspective it is best to keep things simple.
The important thing to understand is that all allergy products are purified proteins produced from organic material. These products mimic the immune response caused by their organic source material (IgE). Over time this repeated exposure mediates the patient’s immune response to the symptom causing source material. The result is sustainable, lasting symptom relief for suffering patients.
How Allergen Extracts are Made (Source: Allergen Science & Consulting)
An overview of allergen extracts (Source: JørgenNedergaard Larsen, PhD&Henning Løwenstein, PhD, DSc)