Why Atara Biotherapeutics Stock Falling In Pre-market?

(RTTNews) - Atara Biotherapeutics, Inc. (ATRA) reported Memorial Sloan Kettering Cancer Center's (MSK) notification to the FDA of a fatal serious adverse event associated with a patient treated in the ongoing phase 1, MSK-conducted dose-escalation clinical study of autologous mesothelin CAR T, ATA2271. MSK has voluntarily paused enrollment of new patients in the study on a temporary basis.

ATA2271 is a next-generation, autologous chimeric antigen receptor (CAR) T-cell therapy targeting mesothelin currently under clinical investigation in patients with malignant pleural mesothelioma.

Jakob Dupont, Head of Global Research & Development at Atara, said: "Clinical evaluation of the case remains ongoing. We anticipate providing a further update in the coming weeks following further discussion and consultation with MSK."

Shares of Atara Biotherapeutics were down 12% in pre-market trade on Friday.