This design, called a "large simple trial," has been used in Europe to assess drugs for heart attacks.

A large clinical trial is currently in progress to continue this study.

The results of a large trial already under way in Thailand will be available late this year.

But the results of a second large trial, announced yesterday, showed no effect.

However, two large clinical trials found no benefits at all.

Even larger trials are still needed, which could take two or three years.

Both drugs showed some effectiveness, but neither company took the drug into larger trials.

Another large trial followed two groups of women for 25 years.

Indeed, a large trial of patients with head injuries showed no benefit.

That history was responsible for creating such large clinical trials.