Last week the Austrian biotech company AFFiRiS published the results of their Phase l clinical trial testing the safety and tolerability of a vaccine treatment for Parkinson's. The therapy - called PD01A - targets a toxic form of the protein alpha-synuclein, which is believed to be involved in the underlying biology of Parkinson's.

Alpha-synuclein is a common protein found throughout the human brain, but for reasons unknown in many cases of Parkinson's, it begins to clump together to form protein aggregates inside neurons. It is believed that this aggregation of the protein is harmful to neurons and researchers have been trying to develop treatments that will reduce levels of the alpha-synuclein aggregates in the brain. The AFFiRiS vaccine uses the body's own immune system to start developing antibodies that target and remove the aggregated form of alpha-synuclein - this type of treatment is called immunotherapy.

In their trial, AFFiRiS recruited 24 individuals with recently diagnosed Parkinson's. The participants were given multiple doses of the vaccine over several years and it was found to be safe and well tolerated. It also caused an antibody-generating response from the immune system and this resulted in a reduction in levels of the aggregated alpha-synuclein in the brain fluid samples of the trial participants. Interestingly, total levels of the 'normal' and uncombined alpha-synuclein were unaffected in the vaccinated individuals, while aggregated alpha-synuclein (which makes up a small fraction of the total) was reduced by around 50%.

It was also reported in the results that both brain imaging data and clinical assessments were "generally stable across the studies" suggesting a possible slowing of the progression of symptoms. The researchers are quick to point out however that this was only a small, open-label trial and it was not designed to test the efficacy of the vaccine. A much larger, double blind, placebo-controlled Phase ll clinical trial will be required to better determine if this vaccine is having an impact on the progression of Parkinson's. AFFiRiS is now preparing to start a Phase ll study in the second half of 2020.

To read more about immunotherapy for Parkinson's - read Dr Simon Stott's blog here.

This study was published in 'The Lancet' - read more here.