An experimental vaccine against Alzheimer's - AADvac1 - was found to be safe and well tolerated but still not adequately effective against cognitive degeneration and capable of having any appreciable effect on the cognitive picture only on subgroups of patients.
This was revealed by the results of a phase 2 clinical trial conducted by Petr Novak of AXON Neuroscience CRM Services SE, in Bratislava.
Reported in the journal Nature Aging, the study involved 196 patients with mild Alzheimer's, some of whom were given the vaccine. AADvac1 instructs the patient's immune system to fight the buildup of tau protein, one of the molecules suspected of being implicated in Alzheimer's or at least some of the cases. The hope of the experts is that by clearing the brain of Tau, the neural damage typical of the disease can be prevented, therefore neurodegeneration, as well as the inexorable cognitive decline that follows.
Experts have seen that the administration of the vaccine corresponds to a specific immune reaction against Tau without however resulting in an improvement in the cognitive picture of the sample. Only at subsequent analyzes were there any small signs of clinical improvement in specific subgroups of patients.
According to experts, the vaccine failed to slow the cognitive decline of patients because the sample was too small and probably only some patients had accumulation of Tau protein in the brain. Therefore, larger studies are needed to adequately test AADvac1 for possible clinical effects of the therapy.