Generic challengers are geared up to erode sales in the market for Parkinson's drugs. The number-two Parkinson's drug by sales in the US, Boehringer-Ingleheim's Mirapex, will lose patent exclusivity January 1, 2010. The generic competition will arrive earlier than expected. The terms of a 2008 settlement between Boehringer-Ingelheim and generic maker Barr Pharmaceuticals give Barr the right to launch generic Mirapex, pramipexole, 10 months before Mirapex's original patent is set to expire. In exchange, Barr (now part of Teva Pharmaceutical Industries) will pay Boehringer-Ingelheim an undisclosed amount in royalties. According to "Neurodegenerative Market Forecast to 2013," a report written by pharmaceutical research firm Cutting Edge Information, the early generic competition will severely impact Mirapex's 2010 sales. "Many analysts had forecast more than $500 million in US Mirapex sales for 2010, but they assumed patent exclusivity through October of that year," said Jeremy Spivey, lead author of the report. "With this settlement, Mirapex is unlikely to surpass $200 million in US sales in that period." Implications will reach beyond Boehringer-Ingelheim in the Parkinson's market. GlaxoSmithKline's Requip XL, for example, is the second highest-selling dopamine agonist. "Generic competition from Barr may easily hurt Requip sales, too," said Spivey. Branded drug makers hope that innovation will make up for patent losses. The standard of care treatment for Parkinson's disease, levodopa, has been off patent for decades. For that reason, little growth is expected from this class in the future. However, several newer therapies are available to treat the condition. Teva's Agilect grossed $170 million in US sales for 2008, and analysts expect sales of $217 million for 2009. Novartis' Comtan earned $502 million in 2008. Other drugs are coming -- analysts expect that Acadia's ACP-103, a developmental drug, will receive FDA approval in 2009.