2seventy bio has announced that an early-stage study of its investigational CAR-T cell therapy in acute myeloid leukaemia (AML) has been paused by Seattle Children’s, the company’s partner and regulatory sponsor of the study, following a patient death.
The phase 1 study has been evaluating SC-DARIC33 as a treatment option for paediatric and young adult patients with relapsed/refractory AML.
The biotech said it had notified the US Food and Drug Administration (FDA) and was investigating the cause of the death, which occurred in the first patient treated at the second dosing level in the trial.
Steve Bernstein, chief medical officer of 2seventy bio, said in a statement: “Importantly, I’d like to offer that our thoughts are with the family during this time. 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 serious adverse event, and the potential next steps for the study.”
AML is a rapidly progressing cancer of the blood and bone marrow. Paediatric AML occurs in seven per million people worldwide, according to data from the National Institutes of Health.
Relapsed AML affects about half of all patients who, following treatment and remission, experience a return of leukaemia cells in the bone marrow. Quality of life declines for patients with each successive line of treatment for AML, and well-tolerated treatments in relapsed or refractory disease remain an unmet need.
2seventy shared positive phase 1 data for SC-DARIC33 in AML last month at the American Society of Gene and Cell Therapy annual meeting.
“The treatment of patients with relapsed and refractory AML represents a tremendous unmet medical need, particularly for paediatric and young adult patients,” Bernstein said at the time. “Progressing the promise of CAR-T therapy, while mitigating potentially dose-limiting toxicity, has the potential to be a meaningful advance.”
He added that the results demonstrated three key steps toward clinically meaningful outcomes: “rapamycin dosing optimisation, rapamycin-regulated in vivo expansion and activation of SC-DARIC33 T cells as well as concurrent anti-CD33 activity”.