The vaccine, developed by Elan Corp., contained Ab, the peptide widely believed to trigger AD by forming brain-clogging amyloid plaques. When Elan researchers vaccinated transgenic mice that had developed AD-like pathology, plaques melted away. Two-and-a-half years of animal experiments yielded further encouraging results. The vaccine prevented and possibly reversed cognitive deficits.1
Last September, Dublin-based Elan and its partner, Wyeth Pharmaceuticals, began a Phase II trial of the vaccine, AN-1792, injecting 375 mildly to moderately afflicted AD patients. In mid-January, the companies suspended further dosing because four patients showed signs of central nervous system inflammation. On March 1, the companies halted the study after 11 more troubling cases turned up.
The complaints—low-grade fevers, headaches, stiff necks—varied among the 15 patients. Two suffered ischemic strokes. "The one common denominator," recalls Ivan Lieberburg, Elan's chief scientific and medical officer, "was that there was an acute worsening of the Alzheimer symptoms, which manifest as ...
