Background

Alternatives reduce the number of animals used in a study, refine studies so the animals are subjected to a milder procedure or completely replace the need for animals.

Computers can predict some behaviours of new medicines.

The latter - replacement - is clearly the most desirable but it is also difficult to achieve. Like all mammals, humans are very complicated and so are the diseases that beset them. At present, it is simply impossible, for example, to recreate the interplay of vital organs, the workings of the immune system, or the most likely toxic effects of a new medicine in non-animal experiments alone.

There is every incentive for scientists to use fewer animals in their research. This is not only for humane and legal reasons, but because animal research is expensive and time consuming.

Alternatives are the law in Britain. The Government will not allow an animal experiment to go ahead if it can be done without animals. Also, each laboratory that carries out animal research has an ethical review process. Those involved will want to know what efforts have been made to find and use alternatives. So too will any organisation, such as a charity, that is funding the research. The funder's ethical review process includes checking that alternatives have been considered.

The description "alternative" is sometimes used as short hand for any non-animal method. Most medical research - over 90% in cost terms - does not use live animals at all. Computers, epidemiology, cells, tissues, imaging, high-throughput screening and clinical trials with people are common non-animal options. Animal research is one of a range of different methods available to scientists when it comes to understanding the mysteries of diseases and their treatment. These methods complement each other. While the non-animal approaches may not have been introduced specifically to replace animal experiments, they often do have that benefit.

Computers are routinely used to study what is likely to happen when a living body breaks down a new medicine in the stomach or liver. The computer programs cannot reproduce every aspect but they can now be trusted to identify some of the factors that would cause a new medicine to fail in humans. In the past that would have required animals.

Artificial organs have been created, such as for the lung and intestine, that can also help discard candidate medicines that are unlikely to work in the way doctors would wish. As with computers, these artificial organs cannot cover everything, and the chemicals that pass this stage will need to be tested on animals later, but they do reduce the overall numbers.

Alternatives that reduce, refine or replace (the 3Rs) are developed in a number of ways. There are organisations (such as FRAME) dedicated to finding new ones, while biomedical researchers and animal technicians themselves are responsible for many innovations. Modern information technology helps enormously here as electronic bulletins of what's new in can be identified and distributed quickly.

All new alternatives face the challenge of being accepted by the scientific community and by those who regulate medical advances. They have to be validated to be sure they are a satisfactory replacement. This takes time.