Doc: Baxter's Gammagard Alzheimer's study done in 2011
A study of Baxter International Inc.'s immune disorder drug Gammagard is slated to finish in 2011, resolving the question of whether the treatment is also an effective therapy for Alzheimer's disease, a doctor said.
Physicians including William Shankle of Irvine, California, have been giving the drug to their Alzheimer's patients for the past five years, even though it isn't approved for the disease, because few alternatives are available. Studies released this week at the International Conference on Alzheimer's Disease show that a healthy diet and regular exercise for the mind and body are the most proven approaches to keeping the illness at bay.
The Gammagard trial will examine 360 patients with mild to moderate disease to see if nine months of treatment improves memory and function. Patients will then be followed for another nine months, when the results will be analyzed, said lead researcher Norman Relkin, director of the Memory Disorders Program at New York-Presbyterian/Weill Cornell Medical Center.
"Enrollment is going at a pretty good clip," he said in an interview at the conference in Vienna today. The trial was designed to detect a much smaller benefit than he expects, particularly if the drug's potency is "even close" to what was seen in earlier trials, Relkin said.
Baxter, the world's biggest maker of treatments for blood disorders, is based in Deerfield, Illinois.
Not Worried
Relkin isn't worried that the study will have too many patients with the APOE-4 gene that predisposed them to Alzheimer's disease. Other therapies, including Wyeth and Elan Corp.'s bapineuzumab, showed benefit only in patients without the gene. Patients with APOE-4 were "overrepresented" in the initial, positive studies of Gammagard, he said.
Shankle, a practicing physician with 900 Alzheimer's disease patients, has used Gammagard since 2004. He presented data on 16 patients at the meeting, and 15 of them had their disease progress less than expected based on their medical history in a best-case scenario.
"In some Alzheimer's disease patients, we're seeing their cognition didn't decline as quickly as it did prior to treatment," Shankle said. He warned about biases that can creep in when research doesn't have a comparison group. "In some cases it did continue to worsen after treatment, but in most cases it was clearly better."
Alzheimer's disease is the leading cause of dementia, affecting more than 5 million Americans and 30 million people around the world. Some researchers believe it is caused by a build-up of a protein, beta amyloid, in the brains of Alzheimer's patients.
Gammagard, derived from donated human blood plasma, replaces antibodies for people whose immune systems can't protect them from infections. The therapy, known as intravenous immunoglobulin treatment, has been used safely for more than three decades for primary immune deficiency disease, a shutdown of the immune system, researchers say.