"I take it, Doctor, your treatments have proven unsuccessful once again."

However by 1993 it was apparent that the treatment had proved inadequate.

Several other treatments that showed early promise have proved useless, doctors said.

The treatment has proved to be effective for issues including:

Despite recognizing the basis for the disease treatment proved difficult.

Everyone was pleased that this treatment did indeed prove effective.

Even if a new treatment proves to be better than the standard, it may not work for every patient.

"Unless the treatment proves to be more involved than we expect."

If the disease develops, early treatment with antibiotics has proved effective for many patients.

Such treatment, however, could prove to be an expensive undertaking, experts say.