Infusions with Gammagard, Drug Used for Alzheimer's, Do Not Halt Advancement of Disease

A drug that was used to slow Alzheimer's disease has failed to slow mental decline or preserve physical function.

Baxter International Inc., the company that tested the product, said it received 18 months of infusions with the drug, Gammagard. According to a study of 390 patients with mild to moderate Alzheimer's disease, the drug was no better than others given as dummy solutions during the study.

Gammagard is immune globulin, natural antibodies culled from donated blood. Researchers thought these antibodies might help remove amyloid, the sticky plaque that clogs patients' brains, sapping memory and ability to think.

Patients with moderate disease and those with a gene that raises risk of Alzheimer's who were taking the higher of two doses in the study seemed to benefit, although the study was not big enough to say for sure.

"The study missed its primary endpoints, however we remain interested by the prespecified sub-group analyses" in groups that seemed to benefit, Ludwig Hantson, president of Baxter's BioScience business, said in a statement.

Gammagard is already sold to treat some blood disorders, and the results of the Alzheimer's study do not affect those uses. About 35 million people worldwide have dementia, and Alzheimer's is the most common type. In the U.S., about 5 million have Alzheimer's. Current medicines such as Aricept and Namenda just temporarily ease symptoms. There is no known cure.

The lead author of the study, Dr. Norman Relkin of Presbyterian Hospital/Weill Cornell Medical Center, finds the study's results disappointing.

"The bar was set very high" for the drug to show improvement, and "there does appear to be a signal" that it helped the two-thirds of patients in the study who had the apoE4 gene that raises the risk of developing Alzheimer's, as well as those with moderate versus mild disease, Relkin said.

According to reports, no new side effects were seen in the study. About 5 percent of patients on the drug had a rash and decreases in hemoglobin, which carries oxygen in the blood. There were 17 serious reactions, 12 in the drug group and five in the placebo group.

Full results will be presented in July at an Alzheimer's conference in Boston.