Chiron Corp. announced Tuesday that the FDA has givenmarketing approval to Proleukin interleukin-2 to treatmetastatic renal cell carcinoma.

The drug is the first approved treatment for the 10,000 casesof the cancer that occur annually in the U.S. Median survivalfor those patients is less than 12 months.

The stock (NASDAQ:CHIR) closed down 75 cents at $47.25. Itrose $6.25 on Monday after the company said it expectedapproval of the drug this month.

Chiron expects the first 12 months of U.S. sales to parallelEuropean sales, which are about $15 million a year, saidspokesman Larry Kurtz. The Emeryville, Calif., company willbegin shipping the drug late this month.

Chiron's Cetus Oncology group, which will market the drug,plans to increase its sales force to 46 from 35 by early summer.The hospital-based direct sales force already markets genericchemotherapy products for the Cetus-Benvenue Therapeuticsjoint venture.

Pricing for Proleukin hasn't been finalized, Kurtz said, but itwill be comparable to the European price of $6,000 to $8,000per course of therapy.

In January, an FDA advisory committee recommended approvalof Proleukin after having turned it down in July 1990. At thetime, the committee had asked the company to provideadditional data and analysis on the drug.

In clinical trials, Proleukin reduced the size of tumors in 15percent of the 255 patients studied. Nearly all patientsexperienced severe or life-threatening side effects, and thedrug-related mortality rate was 4 percent.

-- Karen Bernstein BioWorld Staff

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