Cell Therapeutics stock plunges on negative FDA review of cancer drug

WASHINGTON — Shares of Cell Therapeutics plummeted Monday after U.S. Food and Drug Administration staff raised serious questions about the safety and effectiveness of the biotech drugmaker's experimental cancer treatment.

In documents posted online, FDA staff said the Seattle biotech company's drug pixantrone was associated with potentially fatal cardiac side effects, including heart failure.

Additionally, the agency questioned the strength of the company's study, saying it "enrolled significantly fewer patients than originally planned."

Shares of Cell Therapeutics slid 42 cents, or nearly 40 percent, to 64 cents Monday.

The stock has ranged from 5 cents to $2.23 over the past year; before Monday's sharp decline, it had lost more than a third of its value since June.

The FDA will ask its outside panel of cancer experts Wednesday if pixantrone's benefits outweigh its risks. The agency usually follows recommendations of its advisory committees, though it isn't required to do so.

Options traders have made record bets against Cell Therapeutics ahead of this week's meeting, suggesting they don't expect a favorable review of pixantrone, Bloomberg News reported.

The company has no drugs on the market and has never been profitable.

Cell Therapeutics has asked the FDA to approve the drug for patients who have advanced non-Hodgkin's lymphoma that has returned or is not responding to other treatments. Non-Hodgkin's lymphoma includes a variety of cancers that originate in the lymph system.

The company found that patients taking pixantrone experienced a complete remission of their cancer for a median 5.5 months, compared with 3.4 months for patients using an alternative treatment.

But FDA staff noted that patients taking pixantrone were more likely to experience complications.

Twelve patients in the pixantrone group died of an adverse event, including three from heart failure. That compares with five patients in the control group.

Last year 19,500 patients died of non-Hodgkin's lymphoma, according to the National Cancer Institute.

Life expectancy varies widely depending on the type and stage of the cancer, though more than half of patients live 10 years or more after being diagnosed.

FDA staff noted that the pixantrone study was stopped halfway through because not enough people enrolled, leaving it with 140 patients instead of the planned 320.

"A higher level of evidence is usually required in trials which discontinue before the final analysis," regulators said in their report.

Information from Bloomberg News and Seattle Times staff is included in this report.