Merck Serono is to launch phase III clinical trials of a drug designed to complement dopamine treatments for patients in the early stages of Parkinson's disease.

The firm plans to recruit more than 650 participants who have had the disease for less than five years for the study, designed to examine the safety and efficacy of different dosing regimes of its oral drug Safinamide.

In addition to their standard dopamine agonist therapy, patients will receive a daily dose of one of three types of pill - 50 mg of Safinamide, 100mg of Safinamide or a placebo – for 24 weeks.

Parkinson's causes sufferers to lose control over their movements, resulting in uncontrollable shaking and an inability to move smoothly.

Dopamine therapies are currently given to patients in order to replace the chemical that those with the disease are less and less able to produce as their condition progresses.

Through its named patient supply programmes, Masters can provide healthcare professionals with unlicensed medicines for people who require immediate access to drugs still undergoing clinical trials.