A protein called alpha-synuclein builds up in the brains of people with Parkinson's. This accumulation is believed to play a role in the progressive nature of Parkinson's. Biotech companies have been developing treatments that can remove excess alpha-synuclein, in the hope of slowing or stopping the progression of Parkinson's. One type of treatment being developed is called immunotherapy.

Immunotherapy involves artificially boosting the immune system of the body to target potentially toxic proteins. By teaching the immune system to identify and remove alpha-synuclein, researchers have been able to reduce levels of this protein in the body.

In April the results of a major clinical trial - called the PASADENA study - were announced. The study was testing an immunotherapy treatment targeting alpha-synclein in people with Parkinson's. The results indicated that the trial had not achieved a positive result based on a predetermined measure of success, but the investigators conducting the study indicated that there were ‘signals of efficacy‘ in the data.

Last week, the investigators shared some of the ‘signals of efficacy‘ data at the 2020 Movement Disorder Society meeting. When they pooled the data together and looked at just the motor features of Parkinson's, they found that the treatment called prasinezumab reduced the decline in motor function over one year of treatment, compared to a placebo/control treatment. This means that there was evidence in people treated with prasinezumab of slower progression of motor symptoms.

The treatment was found to be safe and well tolerated. The researchers conducting the study suggest that the results "warrant additional clinical investigation to confirm and extend these findings". The biotech companies conducting the PASADENA study - Roche and Prothena - are now exploring options on how to proceed with the development of this potentially disease modifying treatment.

Further details are available here