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# Clinical Hold on AML Cell Therapy
- URL: https://www.fdaweb.com/clinical-hold-on-aml-cell-therapy/
- Published: 2023-08-14T12:00:00.000Z
- Updated: 2026-09-14T18:50:07.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5155092

FDA has placed a clinical hold on a 2seventy bio Phase 1 study (PLAT-08) of SC-DARIC33 in acute myeloid leukemia after a patient death was reported. The company says it and partner Seattle Children’s have been conducting an internal investigation and root cause analysis of the serious adverse event. “This investigation provided insights into the potential pathobiology of this toxicity which led to several study protocol changes, which the team believes may mitigate this toxicity and allow for the continuation of the PLAT-08 study,” the company says.

SC-DARIC33 is described by the company as an investigational CD33-targeted chimeric antigen receptor (CAR) T cell therapy that “utilizes 2seventy bio’s proprietary Dimerizing Agent Regulated Immunoreceptor Complex (DARIC) T cell platform, a drug regulatable CAR T cell technology. SC-DARIC33 has been shown to be activated by low non-immunosuppressive concentrations of rapamycin in the blood and, when rapamycin is removed, DARIC returns to an inactive state.”

The company says PLAT-08 is being conducted by Seattle Children’s, and it is the first-in-human investigation of the DARIC T cell platform. The death occurred in the first patient treated at the second dose level in the Phase 1 trial, according to the company. “2seventy bio and Seattle Children’s will continue to work with FDA to provide the root cause analysis and proposed changes for the clinical study," it says.