Letter: Biotech patents

Sir: A patent for an invention gives the patent holder a monopoly commercially to exploit his invention for a limited period. A patent does not confer ownership of any physical article, whether human tissue or whatever. To obtain a patent the inventor has to disclose the details of how to perform his invention. These details are subsequently published and are available at the end of the patent term for anyone to use.

The rationale for a patent system is, and always has been, that availability of limited-length monopolies encourages not only innovation but also the disclosure of innovation. The deal between state and inventor is that the limited monopoly is given in return for a contribution of some value to the stock of published technical information. That information can be used by anyone without payment of any fee for "experimental purposes relating to the subject matter of the invention" during the term of the patent, and for all purposes including commercial exploitation at the and of the term.

A patent system based on this rationale has existed in this country for more than four centuries. Where would we be now without it? Modern medicine would be very different indeed.

JAMES MARSHALL

London EC4