Researchers attending a Vancouver conference say a new treatment might help stabilize the mind robbing disease for as much as three years.

But the drug, Gammagard, has been tested in only four patients so far.

Doctors say the four who received the highest dose in early testing showed no decline on memory and cognition tests three years later.

A bigger, more rigorous study of the treatment will give results within a year.

The drug is a collection of antibodies from pooled blood donations given as infusions every two weeks.