Sir

A contradiction exists with the commercial development of chemotherapeutics such as antibiotics, anthelmintics and antiprotozoal agents, and the generation of resistance in organisms to these agents, for which I would like to suggest a solution.

Chemotherapeutic companies invest large amounts of money and effort in research, registration and marketing of new products. This investment is usually protected for 15 years after patent acceptance. However, by the time the product reaches the market the patent period has partially expired (even though in many cases companies are able to recoup investment through additional patent claims and similar patenting strategies).

In some cases the company needs to have optimized its return on investment by the time the patent expires and generic products appear on the market. This means that there is considerable commercial pressure on the company to achieve the greatest possible market penetration and sales volume to service the investment before this time.

As well, in the increasingly global free-market economy that we live in, chemotherapeutic companies are under an obligation to maximize profits for their shareholders, both in the short term and in the long term.

Chemotherapeutic companies have to promote their product in the most effective and efficient manner to ensure their own commercial survival and to maximize the return on their investment, while at the same time trying to husband the use of their products for the greater long-term public good.

This task is a paradoxical challenge for manufacturers, national registration agencies and governments. The use of these agents, as has been repeatedly demonstrated, results in the selection of existing resistant organisms within the population concerned, and/or creates favourable conditions for resistant mutants to thrive.

The cycle of short-term commercial pressure for optimal market return on investment and the resultant generation of resistance should be broken, if possible, in the long-term interests of human and animal health.

A radical and self-regulatory approach to break this cycle could be to link the continuation of a patent to the resistance status of the product. This approach would encourage marketing strategies and patterns of use that are designed to preserve the effectiveness of the preparation and to minimize the development of resistance.

There are likely to be many and varied practical, theoretical and ideological objections to this proposal. Examples are that it is too difficult to change the patent laws and that the nature of the development of resistance is unpredictable.

Is it possible to address this paradox without a lateral approach, such as altering patent laws internationally and reducing the commercial pressure for short-term commercial return on investment?

Any new agents for the chemotherapeutic treatment of bacterial, parasitic and protozoal diseases need to be conserved, if possible, for future generations. To date, the evidence for longevity of the effectiveness of many existing drugs in medicine and animal health has not been good.