Symptom based tests are cited as one reason for the failures of early amyloid clearing drugs for Alzheimer’s. Reviews of patient data following the clinical trials for two drugs—bapineuzumab and solanezumab–found as many as one-third of patients who were enrolled didn’t have the disease they were being treated for—the buildup of a sticky pieces of beta amyloid and tau proteins in the brain, which is the hallmark of Alzheimer’s disease.
But doctors’ reliance on symptom-based testing could soon change. Under new draft guidelines for the diagnosis of Alzheimer’s disease, unveiled on [July 16] at a large international gathering of physicians and researchers, these memory tests would take a backseat to biomarkers—proteins and other signals that can be detected in blood, spinal fluid, and on brain scans—that are telltale signs of the disease process unfolding in the brain.
Such tests have been available to doctors and clinical trial participants but have not been widely applied to patients in clinical practice. Now, with expensive and risky new drugs coming to market that promise to slow the progression of the disease, there’s new urgency for improved diagnosis.
