Late Stage Trial Confirms Effectiveness of Parkinson’s Drug

Parkinson's disease, which is caused by the progressive loss of neurons in a part of the brain that controls muscle movement, has no cure, although there are treatments for specific symptoms of the disease. However, there is a new drug on the horizon that could help slow the progression of the disease and would be a blessing for the 1 million+ Americans that have Parkinson's (including actor Michael J. Fox and boxer Muhammed Ali).

Often called Shaking Palsy, Parkinson's patients experience tremors or shaking, memory loss, stiffening muscles and, as symptoms worsen, they may have trouble walking, talking, or doing simple tasks such as buttoning clothes or feeding themselves. The incidence of the disease increases with age, but an estimated 4 percent of people with Parkinson's are diagnosed before the age of 50. There is also a younger version of the disease, called juvenile Parkinson's, which is diagnosed in adolescents before the age of 18.

A recent 18-month trial, dubbed ADAGIO, included 1,176 patients with very early Parkinson's disease who had not been treated previously. Some patients were given Azilect, also called rasagiline, in strengths of 1 or 2 milligrams once a day for 72 weeks, while others received a placebo for the first 36 weeks before switching to the actual drug. Patients who took Azilect once a day at the outset of the trial experienced a slower decline in disease progression in the early part of the trial and a steadying of symptoms in the latter part. They also experienced a smaller decrease in baseline function. Results were evaluated using the Total-Unified Parkinson's Disease Rating Scale, which measure the symptoms and progression of the disease, including its effects on mental state, motor skills and daily activities.

These findings suggest that early intervention with drugs within months of diagnosis could help delay the onset of more severe symptoms. "They (preliminary results) show that early treatment can result in a slowing of clinical progression," said Professor David Burn of Newcastle University, one of the study authors. "This may offer real benefit to patients." But Dr. Kieran Breen, director of research for the Parkinson's Disease Society, said that while "what we do know is that over a small time period there is an advantage, we really don't know if this will be maintained over the long term."

Azilect was introduced in 2005 and approved to treat the symptoms of Parkinson's. The drug works by inhibiting the production of an enzyme that burns up dopamine, consequently increasing levels of the hormone. Doctors can prescribe it alone, but it is often recommended in combination with levodopa, a drug that the body converts into dopamine, especially for patients in advanced stages of the disease.

Azilect's manufacturer, Teva Pharmaceutical Industries Ltd., now hopes to gain U.S. Food and Drug Administration (FDA) approval to label the drug as a means of stopping symptoms from deteriorating. The company plans to make a formal application by the end of the year, and may get a decision a year later. However, it is possible that the FDA could ask for more tests.

German drugmaker Boehringer is also conducting a test to see if their drug, Mirapex, slows the progression of Parkinson's, according to a statement on their website. Mirapex works by stimulating dopamine receptors, in essence "tricking" the brain into thinking that the hormone is being produced.