Onyx Pharmaceuticals'

(ONXX)

loss doubled in the first quarter, mainly due to costs for trials and marketing of its experimental kidney cancer drug, the company said Thursday.

The cancer-drug maker reported a loss of $16.1 million, or 46 cents a share, in the March quarter, compared with a loss of $8.2 million, or 25 cents a share, a year earlier. The company cited ongoing investment in its cancer drug sorafenib, co-developed with German drug giant

Bayer

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. Analysts expected a loss of 45 cents a share.

Onyx and Bayer received a favorable analysis of a phase III trial of sorafenib in kidney cancer, and the companies are preparing a new drug application for this indication. "Consequently, we anticipate our spending to increase as we build our field sales force and participate in other precommercial marketing activities," said Hollings C. Renton, Onyx president and chief executive.

The company expects a loss for the year of $85 million or more, at the high end of its previously announced range.

For the quarter, Onyx reported revenue of $1 million. First-quarter 2005 revenue represented a payment from Shanghai Sunway Biotech for exclusive rights to a cancer treatment.

On Wednesday, Onyx and Bayer announced that sorafenib was accepted into the FDA's Pilot 1 program for continuous marketing applications. This designation is granted for drugs with fast-track status that may have a benefit over a currently available therapy. Sorafenib was granted fast-track status for metastatic kidney cancer in March 2004.

The Pilot 1 program expedites the continuous marketing application concept, and eligible applicants may submit portions of an application, as new data become available, before submitting the complete new drug application. Under this designation, the FDA guarantees early feedback to the applicant and a review within a specified time period.

Onyx shares ended the day up 2% to $32.33, but lost 22 cents to $32.11 in after-hours trading.