Prof West, of Chicago Medical School, said the main aim of the drugs, only tested in rodents, was to eliminate the "debilitating side effects" of established Parkinson's drugs, such as levodopa.
A "landmark" drug, levodopa's side-effects included a tendency to over-develop the cognitive system which could lead to gambling problems, psychosis, and dyskinesia (involuntary muscle movements).
Parkinson's occurred through degeneration of the dopamine neuron system, particularly affecting "executive centres of the brain", including movement, motivation, and cognition.
The drugs under development required "time and resources" to get them to clinical trial stage, and were likely to be used in conjunction with levodopa or other existing drugs.
Prof West showed the audience a video-clip of rats which had Parkinson's on one side of their bodies. The ability to use their affected paws markedly improved with the new drugs.
Rats' brains were similar to but less complex than humans.
Genes accounted for about 10% of Parkinson's cases. Pesticides and free radicals were implicated in other cases. The association with pesticides meant there was a tendency for those in rural areas to be at greater risk.
Formally identified in London in 1817, Parkinson's was described in Indian literature in 5000BC, and in Chinese writings 2500 years ago, Prof West said.
Prof West said he was delighted to be in New Zealand, on a speaking tour sponsored by the Brain Health Research Centre at the University of Otago and the Neurological Foundation of New Zealand.