FDA panel unanimously votes down Parkinson's drug

[October 18, 2011]  WASHINGTON (AP) -- A federal health panel unanimously voted Monday that a drug for Parkinson's disease from Teva Pharmaceuticals has not been shown to slow progress of the debilitating neurological disease.

Teva's drug Azilect is already approved to treat symptoms of Parkinson's, which causes tremors, muscle stiffness and a host of other movement problems.

The Israeli drugmaker has asked the Food and Drug Administration to expand approval so that Azilect can be prescribed to slow the underlying disease. Currently no treatments are approved for that use.

But the FDA's panel of outside experts voted 17-0 against recommending approval for that use, saying the company's clinical study results were not convincing.

"I believe the drug shows signs of effectiveness for symptomatic use, for which it is already approved. But the higher bar is whether it does anything for disease modification, and it did not meet that standard," said Dr. Justin Zivin of the University of California, San Diego.

Much of the panel discussion revolved around the limitations of Teva's trial design and the difficulty of distinguishing between improved symptoms and actually slowing the disease itself.

Teva studied Azilect in 1,176 patients with very early Parkinson's disease, who had not been treated previously.

Patients were randomly assigned to receive either Azilect or a placebo for nine months, after which those taking placebo were switched to the drug for another nine months. The patients originally on Azilect continued taking the drug for the entire study.

The trial was designed to test whether those taking Azilect for the longer period showed more improvement, suggesting the drug slowed progression of their disease.

A 1 milligram dose of the drug appeared to slow patients' disease based on a rating scale that measures symptoms and disease progression, including its effects on mental state, motor skills and daily activities. But the results were plagued by statistical inconsistencies, and a 2 milligram dose of the drug failed to show similar results.

"In medical science, things have to make sense, and they have to be consistent," said Dr. Eric Ahlskog of the Mayo Clinic, explaining his vote against the drug.

More than 5 million people worldwide, including more than a million in North America, have Parkinson's, according to the National Institutes of Health. The disease is characterized by increasingly severe tremors and periodically stiff or frozen limbs. Patients gradually lose brain cells that produce dopamine, a chemical key to the circuitry that controls muscle movement. There is no cure, although dopamine-boosting medication and an implanted device called deep brain stimulation can reduce some symptoms.

The cause of the disease is unknown.

Earlier in the day, advocates for Parkinson's patients expressed frustration over the lack of clear markers for evaluating drugs' effectiveness for slowing the disease. Some researchers have suggested that brain imaging scans could be used to track disease progression, but so far no consensus has been reached.

"We need a path forward. If this isn't it, what is?" asked James Langston, CEO of the Parkinson's Institute and Clinical Center in Sunnyvale, Calif. "We need guidance if we're going to stay in this field."

Shares of Teva Pharmaceuticals Industries Limited rose 21 cents to $39.50 in afterhours trading.

[Associated Press; By MATTHEW PERRONE]

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