Baxter International Inc. has revealed that in a major study of 390 patients with mild to moderate Alzheimer's disease their blood product known as Gammagard failed to slow mental decline or to preserve physical function.

However according to Reuter's, Gammagard, did show a benefit in some patients with moderate disease and in those who are carriers of a gene known as ApoE4 that raises the risk of Alzheimer's. 

Washington Post reported that "Gammagard is immune globulin, natural antibodies culled from donated blood." In the past researchers thought these antibodies might help remove amyloid, which is the sticky plaque that clogs patients' brains, weakening memory and the ability to think.

Hype began to surround Gammagard last summer when researchers reported at a medical conference that the drug had stabilized Alzheimer's disease for as much as three years in four patients.

The patients had been receiving the highest dose of it for three years in the study. Typically when diagnosed patients go from diagnosis to death in about eight years, so to be stable for such a long period of time was considered remarkable.

The use of Gammagard varies as it is already sold to treat some blood disorders.  An estimated 35 million people worldwide have dementia, and Alzheimer's disease is the most common type.

In the U.S., about 5 million have Alzheimer's disease and it is the sixth leading cause of death in the United States.

Full results of the study will be presented in July at an Alzheimer's conference in Boston. There still remains no cure for Alzheimer's disease.