The drug in his system pretty well proves that.

However, several drugs have proven to be effective in its treatment.

But each drug proved effective for all four symptoms, and neither had significant side effects.

Some scientists familiar with the study have said that the drug has not proved very effective in these tests.

These drugs have proved effective in other chronic pain syndromes.

Amgen said the drug had not proved better than a placebo.

But if these drugs prove successful in people, they will certainly produce a much more functional human being.

Analysts say the drugs could prove the most important product of genetic engineering yet.

In about half of all adult tests, the drugs prove no more effective than placebos.

The drug may eventually prove useful, he said, "but we need further studies."