Shares of Kite Pharma (KITE) fell Monday due to the death of a cancer patient from brain swelling following treatment with the company's CAR-T therapy KTE-C19.

The patient death in a KTE-C19 safety study occurred in April. The FDA was notified but the study was not placed on any clinical hold, Kite said on a Monday morning conference call.

Still, the death rattled investors because death from brain swelling, or cerebral edema, is the same severe toxic event that scuttled a competing CAR-T therapy from Juno Therapeutics (JUNO) .

Kite shares are down 11% to $73.10 in Monday trading.

Until Monday's disclosure, Kite's KTE-C19 development program had not recorded a death due to cerebral edema. The FDA is currently reviewing an application submitted by Kite to approve KTE-C19 for patients with advanced non-Hodgkin lymphoma.

On its Monday call, Kite Chief Medical Officer David Chang said the patient who died had refractory non-Hodgkin lymphoma described as "explosive" and "rapidly progressing" before treatment with KTE-C19. Within two days, the patient's neurological condition deteriorated quickly, leading to death, Chang said.

CAR-T is a new form of cancer immunotherapy in which a patient's own T cells are removed and then engineered to identify and kill malignant blood cancer cells. CAR-T is highly effective at eliminating cancer cells in patients no longer responsive to previous treatments but it's also risky. CAR-Ts are known to cause a dangerous, immune system-related toxicity known as cytokine release syndrome.

Juno Therapeutics was forced to discontinue development of JCAR015 following the deaths of five patients due to cerebral edema.

Top news on TheStreet today:
Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

If you liked this article you might like

Juno, bluebird In Focus as Targets Following Gilead-Kite Aquisition

Faster Rebuild After Harvey; Micron Tech Breakout Would Be a Win: Best of Cramer

Getting Bullish on Gilead

How A Girl from India Came to Rule JPM's North America M&A Group

Stay Focused on the Green Lights: Cramer's 'Mad Money' Recap (Wed 8/30/17)