Updated from 8:55 a.m. EST

Onyx Pharmaceuticals

(ONXX)

bucked its recent history Monday night by offering financial guidance for sales of its Nexavar cancer drug that didn't disappoint.

The Emeryville, Calif.-based biopharmaceutical firm said Monday night that sales of Nexavar would be in the range of $850 million to $875 million this year and more than $1 billion in 2010.

The guidance easily topped the $830 million to $840 million Nexavar consensus range of analysts and investors who follow Onyx, most of whom have grown accustomed to the company offering no long-term forecasts at all, or at best, saddling guidance with so many caveats to make it meaningless.

Onyx shares were recently rising 18.1% to $33.13.

Nexavar was first approved for the treatment of kidney cancer, but the drug's real growth driver has been the subsequent approval in November 2007 as the only targeted therapy against liver cancer. An initial strong launch into the liver cancer market had shown recent signs of slowing, however, which coupled with uncertainties over Onyx's ability to maintain profitability, has weighed on the company's share price.

Onyx was the best-performing biotech stock in 2007, at one point hitting $59 a share. But the stock lost 38% of its value in 2008 and through Monday, Onyx shares were down 17% in 2009.

Gobal Nexavar sales grew 82% year over year to $677.8 million in 2008 and grew 41% to $176.5 million in the fourth quarter, Onyx said Monday. Nexavar is marketed worldwide through a joint venture between Onyx and the German drugmaker

Bayer

. The two companies share equally the profits and costs of marketing the drug, except in Asia, where Onyx receives a royalty on Nexavar sales.

Onyx does not provide earnings guidance, but said Monday that it expects the Nexavar joint venture with Bayer to be "significantly cash-flow positive" in 2009, which will help Onyx achieve profitability as a standalone company this year.

Onyx reported its first annual profit Monday of $1.9 million, or 3 cents a share, in 2008 compared to a net loss of $34.2 million, or 67 cents a share, in 2007.

Going into Monday night's earnings call, analysts were expecting Onyx to lose 3 cents a share in 2008 and earn 93 cents a share in 2009, according to Thomson Reuters.

On a conference call Monday night, Onyx said its long-range Nexavar sales guidance of more than $1 billion in 2010 only assumes the drug is used to treat kidney and liver cancers. The company is conducting phase III Nexavar studies in lung cancer and melanoma, with results from the latter expected later this year. A previous phase III Nexavar study in melanoma failed.

Onyx said Monday that plans are underway to begin a third phase III study of Nexavar in thyroid cancer.

In kidney cancer, Nexavar competes with drugs from

Pfizer

(PFE) - Get Report

,

Wyeth

( WYE) and

Genentech

( DNA), but the drug has the liver cancer market largely to itself.

At the time of publication, Feuerstein's Biotech Select model portfolio was long Genentech.

Adam Feuerstein writes regularly for TheStreet.com. In keeping with TSC's editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet.com. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback;

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