2006-12-31-世界卫生组织-Guidelines_for_assuring_the_quality_and_non-clinical_safety_evaluation_of_DNA_vaccines_25页_248kb

DNA Vaccines: Quality and Nonclinical Safety Guidelines

Introduction Overview

This document provides guidelines for assuring the quality and nonclinical safety evaluation of DNA vaccines, including both prophylactic and therapeutic applications. DNA vaccines involve introducing plasmid DNA into host tissues for in situ antigen production. They offer advantages like B/T cell stimulation, improved stability, absence of infectious agents, and ease of large-scale manufacture. However, they require careful quality control and safety assessment due to potential risks like DNA integration.

Scope and Applicability

The guidelines cover DNA vaccines for human use. They apply to plasmid DNA vaccines manufactured via bacterial systems but not all variants, such as those based on RNA, gene therapy, or non-bacterial delivery. The scope includes quality control (manufacture, characterization, and safety testing) for bulk purified plasmid (drug substance) and final formulated vaccine (drug product). These guidelines are flexible and adapt as the field evolves, based on accumulated experience from clinical and nonclinical studies.

Key Definitions

• Bulk Purified Plasmid (Drug Substance): Purified plasmid DNA before final formulation.
• Final Formulated Vaccine (Drug Product): The finished vaccine product, possibly freeze-dried with excipients or adjuvants.
• Plasmid: Circular bacterial DNA element for autonomous replication, often with expression genes.
• General terms draw from manufacturing processes and materials like master and working cell banks.

General Manufacturing and Quality Control

Plasmid DNA vaccines require adherence to Good Manufacturing Practices (GMP) for production. Key steps include fermentation, purification, and formulation. Controls ensure safety through tests for identity, purity, potency, and stability. Manufacturing must be well-documented, with steps justified and validated where necessary. Flexibility is emphasized to accommodate innovations in delivery methods.

Nonclinical Safety Evaluation

Nonclinical safety testing addresses specific risks associated with DNA vaccines, including potential DNA integration into host chromosomes, immunopathological reactions, and genotoxicity. Evaluations should be product-specific, considering dose, route of administration, and intended clinical use. Testing includes toxicity studies (e.g., local tolerance, biodistribution), immunogenicity assessments, and monitoring for autoimmune responses. Guidelines stress using relevant animal models and integrating data from literature where available.

Conclusion and Recommendations

The guidelines support consistent quality and safety through flexible, case-by-case evaluation. They reflect on accumulated experience from clinical trials and animal studies, emphasizing the need for ongoing updates. Users are encouraged to consult national regulatory authorities for specific applications, ensuring that safety assessments align with the product's clinical purpose, from prophylactic to therapeutic use.