Animal testing for vaccines. Implementing replacement, reduction and refinement: challenges and priorities.

Transition to in vitro alternative methods from in vivo in vaccine release testing and characterization, the implementation of the consistency approach, and a drive towards international harmonization of regulatory requirements are most pressing needs in the field of vaccines. It is critical for global vaccine community to work together to secure effective progress towards animal welfare and to ensure that vaccines of ever higher quality can reach the populations in need in the shortest possible timeframe. Advancements in the field, case studies, and experiences from Low and Middle Income Countries (LMIC) were the topics discussed by an international gathering of experts during a recent conference titled "Animal Testing for Vaccines - Implementing Replacement, Reduction and Refinement: Challenges and Priorities". This conference was organized by the International Alliance for Biological Standardization (IABS), and held in Bangkok, Thailand on December 3 and 4 2019. Participants comprised stakeholders from many parts of the world, including vaccine developers, manufacturers and regulators from Asia, Europe, North America, Australia and New Zealand. In interactive workshops and vibrant panel discussions, the attendees worked together to identify the remaining barriers to validation, acceptance and implementation of alternative methods, and how harmonization could be promoted, especially for LMICs.

Replacement of in vivo human rabies vaccine potency testing by in vitro glycoprotein quantification using ELISA - Results of an international collaborative study.

Three different ELISAs quantifying rabies glycoprotein were evaluated as in vitro alternatives to the National Institutes of Health (NIH) in vivo potency test for batch release of human rabies vaccines. The evaluation was carried out as an international collaborative study supported by the European Partnership for Alternatives to Animal Testing (EPAA). This pre-validation study, the results of which are presented in this paper, compared three different ELISA designs, assessing their within- and between-laboratory precision. One of the ELISA designs was proposed to the European Directorate for the Quality of Medicines & HealthCare (EDQM) and accepted for an international collaborative study under the umbrella of the Biological Standardisation Programme.

Report on the international workshop on alternatives to the murine histamine sensitization test (HIST) for acellular pertussis vaccines: state of the science and the path forward.

Regulatory authorities require safety and potency testing prior to the release of each production lot of acellular pertussis (aP)-containing vaccines. Currently, the murine histamine sensitization test (HIST) is used to evaluate the presence of residual pertussis toxin in aP containing vaccines. However, the testing requires the use of a significant number of mice and results in unrelieved pain and distress. NICEATM, ICCVAM, their partners in the International Cooperation on Alternative Test Methods, and the International Working Group for Alternatives to HIST organized a workshop to discuss recent developments in alternative assays to the HIST, review data from an international collaborative study on non-animal alternative tests that might replace the HIST, and address the path toward global acceptance of this type of method. Currently, there are three potential alternative methods to HIST. Participants agreed that no single in vitro method was sufficiently developed for harmonized validation studies at this time. It is unlikely that any single in vitro method would be applicable to all aP vaccines without modification, due to differences between vaccines. Workshop participants recommended further optimization of cell-based assays under development. Participants agreed that the next international collaborative studies should commence in 2013 based on discussions during this workshop.

Report on the international workshop on alternative methods for human and veterinary rabies vaccine testing: state of the science and planning the way forward.

Potency testing of most human and veterinary rabies vaccines requires vaccination of mice followed by a challenge test using an intracerebral injection of live rabies virus. NICEATM, ICCVAM, and their international partners organized a workshop to review the availability and validation status of alternative methods that might reduce, refine, or replace the use of animals for rabies vaccine potency testing, and to identify research and development efforts to further advance alternative methods. Workshop participants agreed that general anesthesia should be used for intracerebral virus injections and that humane endpoints should be used routinely as the basis for euthanizing animals when conducting the mouse rabies challenge test. Workshop participants recommended as a near-term priority replacement of the mouse challenge with a test validated to ensure potency, such as the mouse antibody serum neutralization test for adjuvanted veterinary rabies vaccines for which an international collaborative study was recently completed. The workshop recommended that an in vitro antigen quantification test should be a high priority for product-specific validation of human and non-adjuvanted veterinary rabies vaccines. Finally, workshop participants recommended greater international cooperation to expedite development, validation, regulatory acceptance, and implementation of alternative test methods for rabies vaccine potency testing.

The consistency approach for quality control of vaccines - a strategy to improve quality control and implement 3Rs.

Current batch release testing of established vaccines emphasizes quality control of the final product and is often characterized by extensive use of animals. This report summarises the discussions of a joint ECVAM/EPAA workshop on the applicability of the consistency approach for routine release of human and veterinary vaccines and its potential to reduce animal use. The consistency approach is based upon thorough characterization of the vaccine during development and the principle that the quality of subsequent batches is the consequence of the strict application of a quality system and of a consistent production of batches. The concept of consistency of production is state-of-the-art for new-generation vaccines, where batch release is mainly based on non-animal methods. There is now the opportunity to introduce the approach into established vaccine production, where it has the potential to replace in vivo tests with non-animal tests designed to demonstrate batch quality while maintaining the highest quality standards. The report indicates how this approach may be further developed for application to established human and veterinary vaccines and emphasizes the continuing need for co-ordination and harmonization. It also gives recommendations for work to be undertaken in order to encourage acceptance and implementation of the consistency approach.