SEATTLE _ Juno Therapeutics said Wednesday it has suspended a phase two clinical trial of a cancer drug after two patients suffered swelling of the brain and died.
The news sent Juno shares plunging as much as 32 percent in early trading Wednesday, the lowest point since the heavily funded Seattle biotechnology company went public about two years ago.
The company's trial for B cell acute lymphoblastic leukemia is testing a drug it calls JCAR015.
The same trial had been temporarily suspended in July after two other patient deaths, but the company blamed those on an additional drug added to the treatment and subsequently changed that protocol.
The two earlier deaths also resulted from swelling in the brain. At the time, the company said it had added a chemotherapy drug to the trial called fludarabine. Juno was able to restart the trial after it removed fludarabine from the treatment.
The trial involves using engineered T-cells designed to attack cancer cells to treat adult patients who have relapsed acute lymphoblastic leukemia.
Juno said Wednesday it notified the Food and Drug Administration of the voluntary hold and is working with the agency and the Data and Safety Monitoring Board to determine the next steps.
Juno's trials and plans for its other product candidates are not affected, the company said.
Juno's fast rise to success was heralded as a major win for the biotech industry in Washington state after its trials treating cancer showed early hopeful results.
The company went public in late 2014 as the biggest biotech IPO of the year. Its stock price rose 45 percent on its first day of trading.
