March 25, 2013
Makers of the experimental drug bapineuzumab, which earlier studies suggested might be beneficial in fighting Alzheimer’s disease, announced that they had halted testing of the drug. The announcement came after late-stage testing found that it did not show benefits in people with Alzheimer’s.
One large clinical trial looked at people with mild to moderate Alzheimer’s who carried the APOE-E4 gene, which increases the risk of developing the disease. It found that compared to a placebo, the drug did not lead to improvements in memory or thinking skills or the ability to carry out day-to-day activities.
A second large trial in people with Alzheimer’s who did not carry the gene also failed to show that the drug provided clear-cut benefits compared to a dummy-drug.
Bapineuzumab targets beta-amyloid, a toxic protein that builds up in the brains of Alzheimer’s patients. It is one of a new class of drugs that aims to target the Alzheimer’s disease process itself, rather than simply easing symptoms of the illness.
Scientists were hopeful that the drug might provide a new approach to treating the disease. Current Alzheimer’s drugs alter chemicals in the brain that may slow deterioration of thinking and memory skills for a time, but they do not target the underlying disease and do nothing to stop its progression.
The disappointing results underline the difficulty of developing successful new treatments for Alzheimer’s disease, and show how early promise can fade with more advanced-stage testing in larger numbers of patients.
Bapineuzumab, like other drugs in development that target beta-amyloid, has been under testing for a number of years. It is what’s known as a monoclonal antibody, a genetically engineered protein that triggers an immune system response.
Several earlier studies had generated some excitement. A report from 2008, for example, found that the drug improved thinking and memory skills in some people with mild to moderate Alzheimer’s. It also seemed to preserve brain volume, a positive sign since a shrinking brain can be a sign of dementia.
Even earlier this year, a Swedish study found that the drug produced changes in the spinal fluid of those with Alzheimer’s that suggested it was having beneficial effects against beta-amyloid in the brain.
“While we are disappointed in the results of the two bapineuzumab studies, particularly in light of the urgent need for new advancements in Alzheimer’s disease, we believe that targeting and clearing beta amyloid remains a promising path to potential clinical benefits for people suffering from this disease,” said Dr. Husseini K. Manji, the head of one of the research divisions that was testing the drug.
Many more Alzheimer’s drugs are under development and advancing to late-stage trials.
Source: Pfizer and Johnson & Johnson. Kaj Blennow, Henrik Zetterberg, Joha O. Rinne, et al: Effect of Immunotherapy With Bapineuzumab on Cerebrospinal Fluid Biomarker Levels in Patients With Mild to Moderate Alzheimer Disease. Archives of Neurology, published online April 2, 2012.