A、 No industries other than the pharmaceutical industry have asked for an extension of the 20-year limit on patent protection.

B、Clinical trials of new drugs, which occur after the patent is granted and before the new drug can be marketed, often now take as long as 10 years to complete.

C、There are several industries in which the ratio of research and development costs to revenues is higher than it is in the pharmaceutical industry.

D、An existing patent for a drug does not legally prevent pharmaceutical companies from bringing to market alternative drugs, provided they are sufficiently dissimilar to the patented drug.

E、Much recent industrial innovation has occurred in products--example, in the computer and electronics industries--which patent protection is often very ineffective.