Onyx Pharmaceuticals Inc. 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 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, reported $447 million in revenue 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.
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.’s Revlimid and Takeda Pharmaceutical Co. Ltd.’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.
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.