By Bruce Japsen
| An immune system drug produced by Baxter International Inc. helped
preserve “thinking” abilities and reduced the rate of brain “shrinkage”
in a small group of patients with Alzheimer’s disease who have been
studied for 18 months, new research released Tuesday shows.

As the pharmaceutical industry continues its search for drugs that could
mitigate the effects of Alzheimer’s, Baxter’s Gammagard showed in a
study of 24 patients that it is among those treatments working well
enough to warrant continued testing. The Deerfield-based company now
will expand its research to more than 350 patients in a final-stage U.S.
clinical trial. If the final-stage trial is successful, Baxter could
submit the product to the U.S. Food and Drug Administration within two
to three years, analysts have said.

The study revealed that 16 of 24 patients had better cognitive response and related improved memory function, showing significantly “less decline in their overall function and thinking abilities” than eight  Alzheimer’s patients on a placebo, according to the data presented by researchers from Weill Cornell Medical College in New York at the American Academy of Neurology meeting in Toronto. The research looked at patients with mild to moderate Alzheimer’s disease who had uninterrupted treatments once or twice a month for 18 months.

Researchers said the use of magnetic resonance imaging, or MRI, of patients’ brains provided an independent measure showing “less whole-brain atrophy.” The typical brain of an Alzheimer’s patient shrinks three to four times faster than a healthy older adult’s brain, as a consequence of accelerated brain cell death, researchers said.

“I don’t think anybody debates that when Alzheimer’s disease progresses, the brain shrinks,” said Dr. Norman Relkin, a professor of neurology at Weill Cornell Medical College in New York in a telephone interview from Toronto where he will present the study Wednesday.

Though MRIs have been used to measure brain shrinkage in the study of potential treatments for Alzheimer’s, such studies do not often cover such a lengthy period of time. “Past Alzheimer’s disease studies that used MRI measures found no change or an accelerated rate of brain shrinkage after investigational treatments,” Relkin said.

Researchers eventually hope Gammagard, a biologic derived from plasma, can prove to change the course of the disease. The idea behind the drug is that it can help the body’s immune system to clear the brain of amyloid, a sticky, plaque-like substance thought to be key in the development and progression of Alzheimer’s.

There is no cure for Alzheimer’s, which affects nearly 5 million Americans, and the number is rapidly rising.