Researchers have been studying a protein called amyloid-β and trying to figure out ways that it could be used as a therapy for Alzheimer’s Disease. The idea of targeting proteins in the body through immunotherapy to aid in the treatment of neurological disorders has been a focus of the scientific community for the last 25 years. However, after the failure of several clinical trials on protein immunotherapy, there has been much criticism and skepticism.
The AN1792 Vaccine Outcomes
One vaccine that has been used to combat amyloid-β is AN1792. This vaccine causes more antibodies to be released in the body which target the protein. In a 15-year study on the effects of this vaccine, researchers found that it was able to suppress the amyloid-β protein. The vaccine activates the immune system’s macrophage cells which removed the protein in the brain.
The unfortunate part is that the decrease in the protein did not improve clinical outcomes. Patients who received the AN1792 vaccine still often ended up with dementia. This means that the removal of amyloid-β from the brain is not adequate by itself to prevent neurological disorders like dementia. Doctors think this indicates that not enough of the antibodies reached the targeted proteins or that the disease had already progressed too far and the treatment came too late. This could mean that targeting the protein through antibodies might be better suited as a preventative treatment, rather than therapy for someone already diagnosed with a neurological disorder.
Other Problems with Immunotherapy & Alzheimer’s
Another problem with these studies on the amyloid-β protein association with Alzheimer’s is that there are many other variables involved. Some patients have greater inflammation in the brain, others have increased fats, and some have heart conditions, all of which play some role in the development of the disease. This could be why studies have shown a reduced number of the protein in the brain, but no clinical improvement. Researchers have begun to test immunotherapy on those who are amyloid-β positive but have also shown no symptoms as a result. More studies are also being conducted on reducing the number of some other proteins that are associated with Alzheimer’s.
The Importance of Timing
The National Institute on Aging (NIA) has been of the institutions conducting research on whether earlier immunotherapy treatment is more effective. In their first study, they chose patients with a high number of amyloid-β, but no symptoms, and gave them a big dose of the vaccine. They hope to find out whether or not the vaccine can deter or delay Alzheimer’s if administered early enough.
The NIA is also experimenting with secondary prevention trials for patients who are likely to inherit Alzheimer’s disease. They use immunotherapy with these patients when they have certain biological traits, but years before they have any kind of cognitive issues. These tests are being done across the United States and Europe, and results are expected to come in the next few years.
Other Problems with Alzheimer’s Treatments
There are a number of other reasons for the potential failure of the amyloid-β protein immunotherapy. One is that the pathology of Alzheimer’s is not limited to that one particular protein, and others may play more important roles in the disease’s development. This could mean that immunotherapy targeting multiple proteins will be the best way to stop Alzheimer’s development. There will need to be extensive testing on this tough, meaning it is probably still a long way away as a treatment for Alzheimer’s patients.
One important thing to keep in mind is that factors other than protein development are almost certainly contributing to the development of the disease. This is most strongly indicated by the fact that aging is a significant risk factor in development.