Drugs companies collaborate on Parkinson's disease treatment

Swiss-based allosteric modulation company Addex Pharmaceuticals and Merck & Co has signed a collaboration potentially worth nearly $170m (E) to develop new types of drugs for the treatment of Parkinson's disease.

Known as positive allosteric modulators (PAM), these new types of drugs will be directed to activate the mGluR4 receptor. This receptor has been found to have a potential role in Parkinson's disease by avoiding the dopaminergic system - the current focus of drug therapies.

This is a new class of compounds that interact in the body away from the traditional drug and endogenous chemical binding sites. Due to this unique mechanism, the company believes its pipeline of drugs have the potential to be at least as effective as current therapies but with significantly fewer side effects.

"Addex has made exceptional progress in the area of mGlu receptor allosteric modulation," said Darryle D. Schoepp, senior vice president and franchise head of neuroscience at Merck Research Laboratories. "This partnership is key to us jointly establishing a leadership position in the promising area of mGluR4 receptor modulation for Parkinson's disease. Merck scientists are excited to work with Addex to extrapolate the full value of this novel mechanism for a range of neuroscience disorders."

Current treatments for Parkinson's focus on dopamine-replacement strategies, however most patients reach a stage where these treatments are no longer effective. There can also be debilitating side effects with current treatments and many patients limit doses so their symptoms are less cumbersome. The recent success of surgical approaches suggests that bypassing the dopamine system may provide a more effective treatment strategy. It is believed that selective activation of mGluR4 is one way to do this and could correct the circuitry that modulates motor excitability. This has the potential to provide significant palliative benefit in Parkinson's disease.

Under the terms of the agreement, Addex will receive $3m (E2m) up-front and is eligible for up to $106.5m (E73m) in research, development and regulatory milestones for the first product developed for multiple indications. Additional milestones of up to $61m (E42m) would be payable if a second and third product is developed. Addex is eligible to receive undisclosed royalties on sales of any products resulting from this collaboration.

Addex and Merck will collaborate on preclinical development. Merck will be responsible for clinical development. Addex has an option to co-promote in certain European Union countries and will participate in the joint oversight committee for clinical development.