Onyx Pharmaceuticals' Cancer Drug Faces Safety Questions

By Brett Chase  JUN 18, 2012 10:45 AM

The biotech company's drug carfilzomib will be scrutinized by a panel of expert government advisers weighing the risks and benefits of US market clearance.


MINYANVILLE ORIGINAL There are some serious questions being raised about the safety of a cancer drug developed by Onyx Pharmaceuticals (ONXX), which may hurt the treatment’s chance of winning US approval.

Food and Drug Administration staff reviewers are worried about the risk of patient deaths and questioned whether the effectiveness of the drug for carfilzomib for multiple myeloma is that great, saying in a report the drug “may not provide an advantage over available therapy.”

“FDA is very concerned with the severe toxicities, including deaths that are associated with the use of this agent,” agency staff said in documents before a panel review of the drug. “The risks of carfilzomib may not outweigh its benefits.”

On Wednesday, a panel of expert advisers to the FDA will meet to weigh those risks and benefits of approving carfilzomib, which would be sold under the brand name Kyprolis for multiple myeloma in people who already received other treatments. Onyx is hoping its drug will ultimately be approved for multiple uses in a broader patient population, which would increase the product’s chances of being a big-seller. The FDA is expected to make a decision about the drug’s approval next month.

The FDA staff is concerned about the risk of heart problems caused by the drug. “The safety data suggests that there are a number of patients with relapsed multiple myeloma who are at high risk of developing life-threatening cardiac toxicities due to carfilzomib,” the reviewers said.

After initially falling, Onyx shares actually rose 1%  to $46.44 in morning trading Monday, which is surprising considering the possibility the drug may face a harsh panel on Wednesday. The stock is up more than 23% in the past three months. While the FDA isn’t bound by any recommendation its advisers give, the agency takes the panel’s deliberations very seriously.

The panel has only one voting question on Wednesday, according to meeting documents: “Is the risk benefit assessment favorable for the use of carfilzomib in the treatment of patients with relapsed and refractory multiple myeloma who have received at least two prior lines of therapy that included a proteasome inhibitor and an immunomodulatory agent?”

Multiple myeloma is a cancer that begins in plasma cells of bone marrow. Patients receive chemotherapy and some will have bone marrow transplants.

Twitter: @brettchase

No positions in stocks mentioned.

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