Another marketing heavyweight, Pfizer ( PFE), could enter the market this year with Indiplon, which was developed by its partner Neurocrine Biosciences ( NBIX). The Food and Drug Administration is expected to rule on the drug in May.

In recent months, however, Sepracor has been gaining more fans on Wall Street. According to Thomson First Call, 11 analysts have buy recommendations, whereas four have either sell or hold ratings. Three months ago, there were eight buy ratings vs. four sell or hold ratings.

One neutral analyst is Michael Tong of Wachovia Securities, who has a market-perform rating on the stock. He told clients Tuesday, just before Sepracor's shares erupted, that although the firm's pipeline "has inherent value, the current share price appears to have reflected fully the company's near-term prospects." He doesn't own shares of Sepracor.

Sepracor's 2006 guidance did nothing to ease the bull-bear split on the stock. The company's estimate of $1.50 of earnings per share and revenue of $1.28 billion exceeded the Thomson First Call forecast of $1.26 a share and $1.2 billion.

This year's guidance "was what the cynics were most concerned with, and that, too, came in well ahead of expectations," says Davis of J.P. Morgan.

However, David Woodburn of Prudential Equity Group believes earnings expectations might be too high. He has an underweight rating on Sepracor even though he says it's "one of the best stories" in the specialty pharmaceutical group. Sepracor's administrative and marketing costs will be greater than expected in 2006, he says.

Woodburn, who doesn't own shares, tells investors to "take advantage of the strength while it exists, instead of waiting for the Indiplon launch," which he forecasts for June.

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