USP's revisions to sterile compounding standards and FDA guidance; impacts on mixing of allergen extracts

United States Pharmacopeia guidance for compounding of allergenic extracts for allergen immunotherapy

Patient-specific allergen-specific subcutaneous immunotherapy (SCIT) has been used as a disease modifying treatment for type 1 IgE mediated allergy to inhalants for > 100 years. Traditionally, the extracts used for a treatment set have been “mixed” under the supervision of allergists in their clinics. Until 2008, there were no specific requirements for mixing procedures. Allergenic extracts are classified as biologics by the U.S. Food and Drug Administration (FDA) and are subject to the biologics license application requirements. One of the conditions is that it must be prepared in accordance with U.S. Pharmacopeia (USP) Chapter 797, which was first published in 2008. What allergists have always considered “mixing” of allergen extracts is considered “compounding” by the FDA and other state and federal regulatory agencies. A revision of USP Chapter 797 was proposed after a series of “never events,” including deaths, from compounded products. No reports of infections from SCIT have ever been reported. “Allergy” (ACAAI, AAAAI, AAOA, and other stakeholders) worked cooperatively with the USP Compounding Expert Committee to develop Section 21. “Compounding Allergenic Extracts” of what is expected to be accepted as the next version of USP Chapter 797 in mid 2022.