July 20 (Bloomberg) -- Johnson & Johnson and Pfizer Inc.’s experimental Alzheimer’s treatment bapineuzumab didn’t raise new safety concerns in study participants monitored over a longer period of time.
Researchers verified the compound’s safety and tolerability beyond 78 weeks in people with mild to moderate Alzheimer’s disease in an extension of a mid-stage trial. Results from an interim analysis of the data are being presented today at the Alzheimer’s Association International Conference in Paris. In data released last year, bapineuzumab was linked to a side effect similar to swelling of the brain when given at high doses.
“The major finding is that there were no new safety signals,” lead researcher Stephen Salloway, chief of neurology and director of the Memory and Aging Program at Butler Hospital in Providence, Rhode Island, said in an interview at the conference. “The types of adverse events that we saw in phase 2, we saw at about roughly the same rate in the open extension.”
Hopes for a medicine to treat Alzheimer’s, which is the most common form of dementia, hinge on bapineuzumab and a similar drug being developed by Indianapolis-based Eli Lilly & Co. Both target beta amyloid plaque, considered by researchers a main contributor to Alzheimer’s. At least a dozen potential treatments designed to slow or stop amyloid plaques from forming have failed in mid- to late-stage testing since 2003.
‘Wait and See’
Bapineuzumab is a humanized monoclonal antibody designed to target beta amyloid in the brain. Monoclonal antibodies, which have broken new ground in cancer treatment, are made in the lab to mimic natural substances that stimulate a patient’s immune system to attack disease-causing cells.
“I am going to take a wait-and-see approach” on bapineuzumab, Marc Gordon, associate professor of neurology and psychiatry at the North Shore LIJ School of Medicine, said in an interview. “Just because you remove amyloid from the brain may not necessarily correlate with an improvement in the condition. The jury is out. We don’t have sufficient data from the phase 2 studies to draw any conclusions on efficacy.”
Out of the 194 participants in the extension trial, some received bapineuzumab for at least three years, some for at least four years and others for five years, researchers said today. Patients were administered bapineuzumab every 13 weeks and there was no placebo group.
The “fairly lengthy time period” is important because bapineuzumab is being considered as a long-running treatment for Alzheimer’s, said Salloway, who also is a professor at Brown University’s Alpert Medical School. It’s not meant to be “just a one-shot, for 18 months,” he said.
Ninety-one percent of the participants reported side effects, and about 24 percent of the individuals reported adverse events that were considered to have a link or possibly have a link with bapineuzumab. Most side effects were mild to moderate, such as headaches. About 35 percent of the patients reported serious adverse events, including convulsion, hip fracture and swelling known as cerebral vasogenic edema, an accumulation of water in the brain tissue, researchers said.
“It continues to be unclear to us if these events are harmful long-term or just short-term markers of drug efficacy,” Marc Goodman, an analyst at UBS AG in New York, wrote in a July 14 note to clients.
Vasogenic edema was the most commonly reported side effect, occurring in 9.3 percent of participants, in line with previous bapineuzumab studies, the researchers said. The risk of developing vasogenic edema appeared to be lower after multiple infusions of the drug, according to the investigators.
“It tends to occur early and doesn’t seem to occur later in the treatment, so that’s very encouraging,” Salloway said. “Most of the vasogenic edema changes occurred with the first three doses, and then over time it’s a much lower rate. I don’t think we’ve seen it at all after two years of treatment.”
Alzheimer’s is a progressive illness that starts with mild forgetfulness and eventually robs patients of memories and independence. It afflicts about 36 million people worldwide, a number that is expected to double by 2050, according to the Alzheimer’s Association, an advocacy group based in Chicago. Existing drugs temporarily ease symptoms and none cure the condition.
Bapineuzumab is in the third and final stage of testing generally needed for regulatory approval. Johnson & Johnson has said it plans to seek U.S. regulatory approval of bapineuzumab in 2012 or 2013. Final-phase results are expected for mid-2012.
“We are getting more familiar” with bapineuzumab and trial results next year will give a “clearer answer on how well the drug works and much more information about safety,” Salloway said.
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