Onyx Drug Reduced Cancer in a Third of Patients With Myeloma in Study

Onyx Pharmaceuticals Inc.’s experimental drug carfilzomib shrank the tumors of one-third of study patients with multiple myeloma, a deadly blood cancer. The company’s shares surged the most in four months in New York trading.

Among 257 patients who had failed to improve on previous treatments, 24 percent had their cancer reduced by half while 10 percent had malignancy reduced by one-quarter, Onyx said in a statement. The reduction in tumor size was maintained for a median of eight months.

Onyx, based in Emeryville, California, will use the results to seek accelerated approval from U.S. regulators by the middle of next year, Chief Medical Officer Michael Kauffman said in an interview on Dec. 1. The results were good for a cancer that is uniformly fatal, said David Siegel, division chief for myeloma at John Theurer Cancer Center at Hackensack University Medical Center in Hackensack, New Jersey.

“You get response, the response lasts and the drug is extremely well tolerated,” Siegel said in a telephone interview on Dec. 3. “That’s what we’re asking for in a drug like this.”

Onyx may have worldwide revenue from carfilzomib of $391 million in 2015, Phil Nadeau, a New York-based analyst for Cowen & Co., said in note to investors on Nov. 4.

The company rose $3.95, or 13 percent, to $33.29 at 4 p.m. in Nasdaq Stock Market composite trading, in Onyx’s biggest single-day jump since July 26. The shares have gained 13 percent this year.

The study, presented today at the American Society of Hematology meeting in Orlando, Florida, followed 266 patients who had relapsed or failed to improve after being treated with medications, including Celgene Corp.’s Revlimid and Thalomid and Johnson & Johnson’s Velcade. Of those, 257 were evaluated for their response.

Competing Drugs

If approved, carfilzomib would compete with Summit, New Jersey-based Celgene Corp.’s Revlimid and Thalomid, which had combined sales of $2.14 billion in 2009. Another drug, Velcade, brought combined revenue of $1.43 billion to New Brunswick, New Jersey-based Johnson & Johnson and Osaka, Japan-based Takeda Pharmaceutical Co.

Multiple myeloma, the second-most-common blood cancer, causes tumors to form in bone marrow and inhibits the immune system. In the U.S., 20,000 new cases are diagnosed each year, and about 10,650 people are expected to die this year from the disease, according to the National Cancer Institute.

Onyx may get accelerated approval on a conditional basis from the U.S. Food and Drug Administration, on the basis of the current studies, if the agency concludes that carfilzomib reduces tumors to the degree that it’s likely to extend patients’ lives. The company would then have to conduct larger, confirmatory studies.

Entering the Market

Early approval may allow carfilzomib to enter the market in 2012 on the basis of current studies, said Howard Liang, an analyst for Leerink Swann & Co. in Boston. If the agency declines to grant accelerated approval and requires Onyx to complete a 700-patient study now under way, the soonest it may bring the drug to market would be 2014, he said.

The earlier date would maximize sales of carfilzomib before the drug faces competition from a cheaper, generic version of Velcade, which may come in 2017, Liang said.

Carfilzomib, like Velcade, belongs to a class of medicines known as proteasome inhibitors that cause cancer cells to die by interrupting their ability to chew up proteins. If the proteins aren’t digested, they overwhelm the cell and kill it, said Kauffman, of Onyx.

Onyx acquired carfilzomib with its November 2009 purchase of South San Francisco-based Proteolix Inc. for $276 million. Onyx’s only current product is Nexavar, a liver-cancer drug marketed with Bayer AG of Leverkusen, Germany. The treatment generated 2009 sales of $843.5 million, an Onyx spokeswoman, Lori Melancon, said in an e-mail.

Nerve Pain

One advantage of carfilzomib is that it causes less of a type of nerve pain known as peripheral neuropathy than Velcade and Thalomid, said Siegel, who led the study. When Onyx researchers analyzed those patients who already had neuropathy when they started taking carfilzomib, they found that less than 1 percent of the patients had their neuropathy worsen. That analysis was released Dec. 5 at the hematology meeting.

“Other drugs cause a lot of neuropathy; this drug causes almost none,” Siegel said. As a result, “most patients are capable of continuing on the therapy.”

Onyx also is testing carfilzomib in combination with Revlimid for patients who have just been diagnosed and haven’t been treated with other medications. In preliminary results involving 31 patients, two-thirds showed little or no signs of cancer after eight rounds of treatment, the University of Michigan said in a statement. After a median of six months, all the patients were still alive, the university in Ann Arbor said in its statement.

The Michigan study was led by Andrzej Jakubowiak, director of the multiple myeloma program at the university’s Comprehensive Cancer Center. The results were presented yesterday at the hematology meeting.

To contact the reporter on this story: Rob Waters in San Francisco at rwaters5@bloomberg.net.

To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net.

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