Teva Pharmaceutical Industries Ltd. said Tuesday its Azilect pill is the first to slow the progression of Parkinson's disease in new findings that may increase sales of the medicine to more than $1 billion. Patients who took the one-milligram dose of Azilect at the outset of an 18-month trial showed "significant improvement" over patients who started nine months later, Petah Tikva-based Teva said in a statement. The test results were presented at a medical conference in Madrid on Tuesday. Azilect, Teva's second original product, was introduced in 2005 to treat the symptoms of Parkinson's, an incurable disease that destroys patients' nerve functions. Teva needs to replace revenue from its first original drug, Copaxone for multiple sclerosis, before it loses patent protection in 2014. Peak sales of the Azilect pill may now surpass $1b., instead of an estimated $250 million a year, said Ronny Gal, who follows Teva at Sanford C. Bernstein in New York, in a June 16 interview. "The importance of this news is that there is scientific confirmation that has been presented before an audience of doctors," said Yoav Burgan, an analyst at Leader Capital Markets Ltd. in Tel Aviv. The data may increase Azilect's share of the $3.68b. global market for Parkinson's disease medicines, said Moshe Manor, who heads Teva's innovative-drug development. "Now it's proven that if you treat earlier, you can protect the patient from further deterioration," Manor said in a telephone interview Tuesday. "This slowing-down effect will probably continue to be sustained over time." Teva rose 53 cents, or 1.1 percent, to $47.11 at 11:19 a.m. in New York. In Tel Aviv, the stock closed up NIS 2.8, or 1.7%, at NIS 166.80. Burning dopamine Parkinson's disease strikes when patients lose brain neurons that produce dopamine, a hormone that helps transmit signals from the brain to the body. The disruption to the nervous system causes tremors, difficulty in speaking and walking, and depression. Azilect inhibits production of an enzyme that burns up dopamine, thereby increasing levels of the hormone. Doctors can prescribe it on its own, though they often recommend it in combination with levodopa, a drug that the body converts into dopamine. Early intervention Tuesday's findings on Azilect could support a strategy of "early intervention," said Anthony Schapira, a neurologist at the Royal Free and University College Medical School in London, before the data was released. Currently, most Parkinson's specialists wait until the symptoms become disabling before putting patients on a drug regimen, he said. Neurologists will want to examine the trial results before changing their prescribing habits for Azilect, said Kieran Breen, director of research at the UK Society, in an August 11 telephone interview. "That's one of the big problems with Parkinson's - it's such a heterogeneous condition you have to look at a large number of people over a long period of time," Breen said. The expanded use of Azilect could propel Teva's share price above $50 in New York for the first time, said Gilad Alper, an analyst at Excellence Nessuah in Tel Aviv, before the data was released. Azilect prescription numbers began to climb on June 16, when Teva first said the study had achieved all its main goals without disclosing what the goals were, Manor said. He declined to say how much sales have increased. Azilect's label Teva will use the data to try to persuade the US Food and Drug Administration to label Azilect as a means of stopping symptoms from deteriorating. The company plans to make a formal application by year's end, and may get a decision a year later. It's also possible the FDA may ask for more tests, Manor said. Teva developed the medicine with Danish drugmaker H. Lundbeck A/S. The pill had sales of $120m. last year, compared with $950.6m. for Boehringer Ingelheim GmbH's Mirapex and $693m. for GlaxoSmithKline Plc's Requip, according the companies' annual reports. Boehringer is also conducting a test to see whether Mirapex slows the progression of Parkinson's, according to a statement on the German company's Web site. Boehringer's drug works by stimulating dopamine receptors, "tricking" the brain into thinking that the hormone is being produced. Teva plans to publish the study in a peer-reviewed journal, Manor said, declining to give details. "I think the data speaks for itself," he said.