The first patient has been vaccinated with an active tau vaccine, AADvac1 (Axon Neuroscience), in the phase 2 ADAMANT trial. AADvac1 was developed to be the first disease-modifying tau vaccine for patients with Alzheimer’s disease (AD) and other tauopathies.
The ADAMANT trial is a 24-month, randomized, placebo-controlled, parallel-group, double-blind, multicenter study designed to assess the safety and efficacy of AADvac1 in patients with mild AD. It is being conducted in Europe in a total of 185 patients. The study’s primary objective is to confirm positive phase 1 results by assessing the safety and immunogenicity of AADvac1 in a larger patient population. In the phase 1 study, which was conducted in Austria in 30 patients, 80% of the vaccine responders generated titers higher than 1:10,000. The new study’s secondary objective is to evaluate the efficacy of AADvac1 in slowing or halting cognitive decline during 24 months of treatment. The study is powered to show the disease-modifying effect of the vaccine on the Clinical Dementia Rating Sum of Boxes, supported by a custom cognitive battery (a composite standard score), and the Activities of Daily Living Scale.
AADvac1 was designed to elicit antibodies against tau proteins, the main constituents of neurofibrillary tangles in AD. Tau protein pathology was identified as the main correlate of cognitive decline in AD in the early 1990s. This finding was confirmed by several independent studies in animal models expressing diseased forms of the tau protein, where tau pathology induced neurodegeneration and caused cognitive impairment. Recent imaging studies have shown that the progression of tau pathology correlates with the cognitive decline and memory loss associated with AD.
According to Axon Neuroscience, AADvac1 is the first vaccine against AD that was able to overcome the low antibody responsiveness typically seen in elderly subjects.