Juno Therapeutics suspends drug trial after new patient deaths

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.

This is the second time the trial has been suspended in the past six months because of patient deaths.

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 in a hugely successful stock-market debut nearly two years ago. The stock closed the regular trading day Wednesday at $22.56, down 24.5 percent.

The company’s “Rocket” trial for B cell acute lymphoblastic leukemia – or ALL – is testing a drug it calls JCAR015. The trial involves using engineered T-cells designed to attack cancer cells to treat adult patients who have relapsed acute lymphoblastic leukemia.

The same trial had been temporarily suspended in July after two other patient deaths, but the company blamed those primarily on an additional drug added to the treatment. It subsequently changed that protocol.

The two earlier deaths also resulted from swelling in the brain, called cerebral edema. At the time, the company said it had added a chemotherapy drug called fludarabine to the trial. Juno was able to restart the “Rocket” trial after it removed fludarabine from the treatment.

Executives said Wednesday that they still believe removing fludarabine was the right move, though they reiterated that the deaths were likely caused by more than one factor.

Juno’s fast rise to success was heralded as a major win for the biotech industry in Washington state after 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.