How AADvac1 works
AADvac1 works by inducing an immune response against a protein called tau, which is abnormal in Alzheimer’s disease. The protein agglomerates, or clumps together, and forms so-called neurofibrillary tangles inside the brain cells. These tangles disrupt the normal functioning of neurons and were identified as one of the primary reasons for cognitive impairment in people with Alzheimer’s disease.
Upon administration, the AADvac1 vaccine induces a patient’s immune system to produce specific antibodies that target abnormal forms of the tau protein. The aim is to protect the neurons from dying.
AADvac1 in clinical trials
AADvac1 has been investigated in several clinical trials. The first human study (NCT01850238) to assess the safety and tolerability of subcutaneous (below the skin) injections of AADvac1 in patients with Alzheimer’s disease was initiated in 2013. Patients received either AADvac1 or a placebo. The results, which were published in the scientific journal Lancet Neurology revealed that AADvac1 had a favorable safety profile. It was also found that the vaccine effectively recognized the pathological forms of tau proteins in the brain of patients with Alzheimer’s disease, a response that could prevent the progression of the disease.
A follow-up Phase 1 study (NCT02031198) then assessed the tolerability and safety profile of AADvac1 in patients with mild-to-moderate Alzheimer’s disease. The results of this study, which is now complete, were announced at the 13th International Conference on Alzheimer’s & Parkinson’s disease in 2017. They indicated that AADvac1 recognized tau protein in other neurodegenerative diseases as well as Alzheimer’s, including corticobasal degeneration and progressive supranuclear palsy. The findings provide strong evidence that antibodies produced by AADvac1 target the common denominator (the tau protein) in different diseases.
A 24-month randomized, placebo-controlled Phase 2 trial (NCT02579252), known as ADAMANT, involving patients with mild Alzheimer’s disease investigated the safety and tolerability of AADvac1. Initial results were announced in September of 2019 and showed that 98.2% of patients who were given the vaccine generated anitbodies to the tau protein. The results also showed no difference in adverse events between the treatment and control groups, meaning that the treatment was well tolerated. The change in several biomarkers for Alzheimer’s disease showed trends that suggest AADvac1 may slow the progression of the disease. The slowing of the progression was also supported by positive changes in several cognitive endpoints. Based on the results, Axon is now looking for a global partner to continue the next level of clinical trials.
The safety of AADvac1 is also being investigated in a 24-month Phase 1 pilot study (NCT03174886) in patients with non-fluent primary progressive aphasia (AIDA), a progressive neurodegenerative disorder that is also linked to abnormal tau proteins. The disorder affects the ability to speak, read, write, and understand what is being said. The trial is currently recruiting participants in Germany and is expected to be completed by mid-2020.
Last updated: October 1, 2019
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