Response by Festing & Wilkinson

The commitment of the scientific community to developing alternatives to refine, replace and reduce the use of animals in scientific research and regulatory toxicology has been shown many times. New methods have revolutionized high‐throughput screening for the pharmaceutical industry, and thus reduced the need for tens of thousands of animals. From simple advances like pregnancy tests, to complex brain imaging techniques, scientists—not anti‐vivisectionists—are continually developing new methods to replace the use of animals.In some cases these new tests can outperform animal studies and their use should be applauded, but to make the generalization that non‐animal methods are therefore ‘superior’ in all areas of biomedical research, or to make a broad judgement as to ‘relative efficacy’, is scientifically meaningless. Scientific methods can only be assessed on a case‐by‐case basis. For example, computer modelling is good at predicting protein folding, but isolated human cells will never be able to tell us the full story about the regulation of blood pressure.The Dr Hadwen Trust might make a small contribution to the field of replacement techniques; nonetheless, Gill Langley is a well‐known anti‐vivisectionist who uses the debate about alternative methods to undermine the use of all animals in research wherever possible. It is true that non‐animal methods can sometimes overcome the limitations of animal studies, nevertheless, in many cases, animal studies are needed to overcome the limitations of alternative methods—as with the blood pressure example just given. In vitro studies can actually have a much higher failure rate than animal studies in predicting what will happen in humans. The Ames test to assess the mutagenic potential of a chemical, for example, is riddled with false positives. There are also strict ethical limitations about what can be studied in humans. This is why, as responsible scientists, we must use all available research methods, …