Regulatory Requirements for the Quality of Allergen Products for Allergen Immunotherapy of Food Allergy.

PURPOSE OF REVIEW: Medicinal products for allergen immunotherapy (AIT) of food allergies have gained enormous momentum in recent years. With this new class of products entering marketing authorization procedures, compliance to regulatory requirements becomes a critical element. Here, an overview is provided on specific requirements and aspects concerning the quality control and manufacturing of these products. RECENT FINDINGS: Recent developments in the field of AIT for food allergies are divers, including products for oral, epicutaneous, and subcutaneous application, most notably targeting egg, milk, and peanut allergy. As the source materials for food AIT product are typically produced for food consumption and not for medicinal purposes, unique challenges arise in the manufacturing processes and controls of these medicinal products. Individual approaches are needed to assure acceptable quality, including control of relevant quantitative and qualitative characteristics. Major characteristics for quality verification include determination of protein content, total allergenic activity, and major allergen content. The applied manufacturing processes need to be established such that relevant process parameters are kept within justified limits and consistency of produced batches is assured. Allergen products for food AIT present specific challenges with respect to quality aspects that differentiate them from other commonly available AIT products. While established regulation is available and provides clear guidance for most aspects, other issues require consideration of new and individual settings relevant here. Consequently, as experience grows, respective amendments to currently available guidance may be needed.

Regulatory aspects of specific immunotherapy in Europe.

PURPOSE OF REVIEW: The recent developments in the regulation of allergen products and their impact on specific immunotherapy (SIT) in Europe are summarized, and unmet needs are discussed. RECENT FINDINGS: New guidance on the quality, the clinical development, and marketing authorization status of allergen products for SIT has been released. The most important documents are Guidelines from the European Medicines Agency, a revision of the European Pharmacopoeia Monograph on Allergens, regulations, and position papers of scientific societies. SUMMARY: The increased demands on quality, safety, and efficacy will lead to allergen products being better characterized and with enhanced proof of efficacy and safety. In addition, national activities to regulate the existing broad spectrum of named patient allergen products have been started. At the same time these developments represent a challenge to manufacturers to meet all new requirements. Some problems, for example regarding patient-tailored products containing recombinant allergens remain and may require novel regulatory approaches.

Fragment-based lead discovery: screening and optimizing fragments for thermolysin inhibition.

Fragment-based drug discovery has gained a foothold in today's lead identification processes. We present the application of in silico fragment-based screening for the discovery of novel lead compounds for the metalloendoproteinase thermolysin. We have chosen thermolysin to validate our screening approach as it is a well-studied enzyme and serves as a model system for other proteases. A protein-targeted virtual library was designed and screening was carried out using the program AutoDock. Two fragment hits could be identified. For one of them, the crystal structure in complex with thermolysin is presented. This compound was selected for structure-based optimization of binding affinity and improvement of ligand efficiency, while concomitantly keeping the fragment-like properties of the initial hit. Redesigning the zinc coordination group revealed a novel class of fragments possessing K(i) values as low as 128 microM, thus they provide a good starting point for further hit evolution in a tailored lead design.