This seems like the best news I've seen although it's not clear to me if this would work for advanced PD. If this gene therapy works in monkeys, why not humans? How many years of clinical trials must we wait for now?

Vector-mediated l-3,4-dihydroxyphenylalanine delivery reverses motor impairments in a primate model of Parkinson’s disease


Vector-mediated l-3,4-dihydroxyphenylalanine delivery reverses motor impairments in a primate model of Parkinson’s disease | Brain | Oxford Academic



In summary, the results obtained in this study provide proof-of-principle for AAV-mediated l-DOPA delivery as a therapeutic strategy for Parkinson’s disease. This refined version of classic l-DOPA treatment is attractive in that it is based on a single intervention and targeted to the site in the brain where dopamine is most needed, i.e. the striatum. The constant local supply of l-DOPA obtained with this approach holds promise as a therapeutic intervention that can provide long-lasting clinical improvement and, in the best cases, also avoid the appearance of motor fluctuations and dyskinetic side effects associated with standard oral dopaminergic medication. This gene therapy approach may thus offer the possibility to prolong and sustain the ‘good years’ many patients with Parkinson’s disease experience during the initial stages of l-DOPA therapy.