Boxes of Gammagard, a treatement that is being tested for Alzheimer's disease.

For the first time, researchers are reporting that a treatment might help stabilise Alzheimer's disease for as much as three years, but the evidence is weak and only in four patients.

The treatment is Gammagard, made by Baxter International. Doctors say four patients 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. These antibodies may help clear the sticky plaque that clogs patients' brains.

The results were discussed on Tuesday at an Alzheimer's conference in Vancouver, British Columbia. - Sapa-AP