Study: Baxter drug helps Alzheimer's patients

Baxter International's treatment for immune system disorders also helped Alzheimer's patients retain brain size and function after 18 months in a study that suggests the drug may top current regimens, researchers said.

Brain scans from 14 patients taking Gammagard didn't show the excessive brain shrinkage that's a hallmark of mental decline in Alzheimer's, according to a study funded by Deerfield-based Baxter. Mental capacities improved, with benefits continuing over the full 18 months of the study, outlasting current regimens, researchers said today.

Alzheimer's, a progressive, incurable illness, afflicts 30 million people worldwide, according to the Centers for Disease Control and Prevention in Atlanta. If cleared by U.S. regulators for use against the disease, Gammagard would join a $7.5 billion global market, said IMS Health Inc., a Norwalk, Connecticut- based industry research firm. Versions of the intravenous drug have been marketed for other illnesses since 1995.

"Unequivocally, this trial succeeded," said Norman Relkin, the study's principal investigator and a neurologist at New York-Presbyterian/Weill Cornell Medical Center, in a telephone interview. "The improvement was equal to 6 to 12 months of disease progression being reversed, but the even more important effect is the maintenance over time."

There hasn't been a new drug approved for Alzheimer's since 2003 when Namenda, which had $950 million in sales last year for New York-based Forest Laboratories Inc., was cleared. Gammagard would compete with market-leader Aricept, made by New York-based Pfizer Inc. and Tokyo-based Eisai Co., which generated about $3.5 billion in revenue last year.

Seeking Novel TreatmentsAlzheimer's starts with mild forgetfulness and eventually robs patients of memories and independence. Doctors and patients are looking for novel treatments that slow the progression of the illness and allow patients to remain in their homes and take care of themselves for longer periods of time.Results from the first six months of the Gammagard study were reported in 2008, without the brain scans. Sixteen patients were given the drug and eight patients were given saline solution to compare results. After the six months, patients taking the placebo were switched to Gammagard.Results from the complete 18-month study were released today and are scheduled to be presented tomorrow at the American Academy of Neurology's annual meeting in Toronto.The next round of tests needed for U.S. marketing approval is enrolling patients at 35 sites in the U.S., with 12 more sites pending in the U.S. and Canada, according to a statement from New York-Presbyterian. Enrollment in the 18-month study of 360 people will be completed in late 2010, said Andrew Lewis, a spokesman for Baxter, in a telephone interview.Another Study StartsAn additional study to bolster the application for regulatory approval was announced today and will be conducted simultaneously, Lewis said.Gammagard and most competing experimental drugs for Alzheimer's are designed to reduce levels of amyloid plaque -- spaghetti-like clumps of protein that accumulate in the brains of patients. Gammagard, made from a pool of thousands of human blood plasma donations, contains a variety of amyloid-fighting antibodies, Relkin said. It also fights inflammation, which is associated with Alzheimer's disease.Gammagard is designed to replace antibodies for people whose immune systems can't protect them from infections. Future generations of the drug may target specific antibodies from the mix that are found to be most effective against Alzheimer's disease, Relkin said.Nurses VisitedIn the trial released today, nurses visited patients' homes to administer one of several doses of the infusion, either once or twice a month. For those taking the most effective dose, some brain functions improved and the rate of brain size decline was similar to that of a healthy person of the same age.When all dose groups were considered together, the speed of brain shrinkage and degradation was faster than in healthy people but slower than other Alzheimer's patients.Gammagard side effects include possible harm to the kidneys, and patients need regular testing, according to the drug's prescribing information. Kidney impairment wasn't seen in the Alzheimer's study, Relkin said.Brains cells of Alzheimer's patients die at an accelerated rate, typically causing patients' brains to shrink three to four times faster than the brain of a healthy person of the same age, according to the New York-Presbyterian statement. The shrinkage causes fluid-filled ventricles at the brain's center to expand. The sizes of both the brain and ventricles were measured using Magnetic Resonance Imaging tests, or MRI.Learning New SongsOne patient, a piano player, regained his ability to learn new songs. Before the study the patient played the same four songs repeatedly, a pattern typical of the disease, Relkin said. After two months, the patient's wife and son came to Relkin's office to report the musician had taught himself a new song."By the end of the year he had several new pieces, and at last count there were over 20 compositions that he had mastered," Relkin said. "In all my years of doing this, it's just extraordinarily unusual to hear of someone who is learning and actually expanding their repertoire in the course of having this disease."