Recent developments in replacing, reducing, and refining animal use in toxicologic research and testing.

Significant progress has been made in replacing animals in toxicology/safety assessment with in vitro systems, in reducing the number of animals used, and in refining how they are used. Review of annual reports of the numbers of animals used in testing in the United States, the United Kingdom, and Japan shows a continuing reduction in the numbers for all species. Multiple in vitro systems have been developed for screening/testing for eye and skin irritation, skin sensitization, teratology, and other endpoints and a scientific consensus has been formed on requirements and process for validation. However, the use of these test systems in place of existing in vivo tests is minimal. At the same time, innovative designs have been developed (and are in wide use) for in vivo tests which reduce both the numbers and the pain and distress of animals used in testing. Progress and dialogue continue on modification of both U.S. and international requirements and guidelines for testing, and for defining an "approval" process for alternatives and innovations.