Onyx's Cancer Drug's Risk May Outweigh Benefit, FDA Says

Onyx Pharmaceuticals Inc. (ONXX) (ONXX) fell the
most in two weeks after U.S. regulators said its drug for a
deadly blood cancer may not offer enough benefits over current
therapies to outweigh risks including chest pain and pneumonia.

Onyx dropped 4.1 percent to $44.08 at the close in New
York, the biggest single-day decline since June 4.

The medicine, with the proposed name Kyprolis, shrunk
tumors in 22 percent of multiple myeloma patients, which may not
offer enough of an advantage in light of the side effects, Food
and Drug Administration staff said today in a report ahead of a
June 20 advisory panel meeting. Five patients died from heart
problems, the FDA said. Onyx, based in South San Francisco,
applied for accelerated approval of the treatment based on the
second of three phases of trials typically needed for approval.

"This is a drug that will get approved," Michael King, an
analyst with Rodman Renshaw in New York, wrote in an e-mail
today. "It's just a matter of when."

If approved, yearly sales for the drug may be $523 million (ONXX)
in 2016, according to the average of five analysts' estimates
compiled by Bloomberg. Onyx, the maker of the kidney cancer drug
Nexavar in a partnership with German drugmaker Bayer AG (BAYN),
reported $447 million in revenue (ONXX) last year.

Side effects for the treatment, known chemically as
carfilzomib, also included cardiac arrest and shortness of
breath, the FDA staff said. More than 70 percent of patients had
lung complications with the drug, according to the FDA report.

'Severe Toxicities'

The agency "is very concerned with the severe toxicities,
including deaths that are associated with the use of this
agent," the FDA staff said in the report.

Carfilzomib would be used to treat multiple myeloma
patients who have first tried Celgene Corp. (CELG) (CELG)'s Revlimid and
Takeda Pharmaceutical Co. Ltd. (4502)'s Velcade.

About 50,000 people in the U.S. are living with the disease
and 20,000 new cases are diagnosed each year. About 11,000
patients die of the disease annually, according to the National
Cancer Institute.

FDA determined "a very small fraction" of the 266
patients Onyx intended to treat in its main trial, or 69 people,
were unresponsive or intolerant to the already approved drugs.

The FDA is scheduled to make a decision by July 27.

"Multiple myeloma still has one of the lowest survival
rates of any cancer so there's tremendous unmet medical need,"
Anne Quinn Young, vice president of strategic alliances, at the
Multiple Myeloma Research Foundation in Norwalk, Connecticut,
said.

38% Survival

The cancer has a 38 percent survival rate after five years,
Young said. Often when patients who've tried Revlimid and
Velcade relapse, their options are high doses of chemotherapy
and steroids.

"These treatments are extremely toxic and it's sad," she
said

The foundation helped Onyx with the clinical trials on the
drug and assists the company with an expanded access program
that has allowed about 250 patients not in clinical trials to
obtain the treatment.

To contact the reporter on this story:
Anna Edney in Washington at
aedney@bloomberg.net

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