Michael J. Fox Foundation (MJFF) Associate Director of Research Programs Maurizio Facheris, MD, MSc, is providing updates from this year’s American Academy of Neurology (AAN) Annual Meeting. Here, Maurizio highlights three projects of note that he encountered in San Diego that have ties to Parkinson’s disease (PD).
1) The Foundation continues to support drug development programs targeting a particular dopamine receptor called D1. One hypothesis in Parkinson’s disease is that slowing D1’s activity could help to reduce dyskinesia. One company presenting this week at AAN called Psyadon has a D1 antagonist program for tic/Tourette’s syndrome that is already in clinical testing. They are interested in potentially expanding into PD.
There’s still a lot to learn about a potential anti-dyskinetic role of D1 antagonists, but it’s good to see that another company is working to develop this class of drugs. MJFF is also supporting other projects that look to do the opposite, and activate D1, as a potential symptomatic therapy for PD.
2) Santa Clara, California-based biotech XenoPort has developed a technology to improve the absorption of drugs such as levodopa into the body, which could, in turn, provide more consistent therapeutic benefit for Parkinson’s patients. Xenoport’s therapies in development work by catalyzing naturally-occurring “nutrient transporters” in the gastrointestinal tract to generate this more efficient absorption. Already, the company has oral drugs on the market for restless leg syndrome and chronic pain.
Their PD drug candidate using the technology, called XP21279, recently completed phase 2 clinical testing, and an open label portion of the study showed improved “on time” in Parkinson’s patients when compared to those taking Sinemet. A double-blind phase of the study, however, did not prove to show statistically significant improvement when comparing XP21279 with Sinemet. A phase 3 study into the drug is likely to follow in order to confirm efficacy on a larger scale.
3) The University of Saskatchewan has conducted an interesting analysis showing amantadine, often prescribed off-label for levodopa-induced dyskinesias, does not delay the onset of this troublesome side effect when taken prior to beginning a Sinemet regimen. The study found that those who added amantadine after beginning such a regimen had the same rate of dyskinesia. The study was not designed to measure whether amantadine has a therapeutic effect in limiting the severity of dyskinesias – this could of course still very much be the case. Again, this study focused on the drug’s effects on the onset of dyskinesias.