Death of Patient Causes Hold in Study of 2seventy Bio’s Experimental AML Therapy

Rare Daily Staff

Seattle Children’s has placed a hold on a its phase 1 trial of the PLAT-08 study of 2seventy Bio’s experimental therapy SC-DARIC33 to treat the rare blood cancer acute myeloid leukemia following the death of a patient in the study.

The pause was instituted as part of the clinical study protocol stopping rules in response to a recent fatal serious adverse event. The company, an immune-oncology spin-off of Bluebird Bio, notified the U.S. Food and Drug Administration of the death and trial hold. The root cause of this serious adverse event and its potential relationship to the study drug is currently under investigation.

SC-DARIC33 is an investigational CD33-targeted CAR T cell therapy that utilizes 2seventy bio’s proprietary Dimerizing Agent Regulated Immunoreceptor Complex T cell platform, a regulatable CAR T cell technology.

PLAT-08 is the phase 1 study of SC-DARIC33 in relapsed/refractory pediatric AML, conducted by Seattle Children’s. The study is a first-in-human investigation of the DARIC T cell platform. The serious adverse event occurred in the first patient treated at the second dose level in the phase 1 trial.

“The safety of every patient who participates in our studies or is treated with our therapies is the utmost priority for us, and we are in communication with FDA while we assess the data surrounding this SAE, and the potential next steps for the study,” said Steve Bernstein, chief medical officer of 2seventy Bio.

Photo: Steve Bernstein, chief medical officer of 2seventy Bio