Instil Bio, Inc. notified the U.S. Food and Drug Administration and other regulatory agencies that it has voluntarily paused enrollment in DELTA-1, the Company's Phase 2 clinical trial of ITIL-168 in patients with advanced melanoma. No regulatory agencies, including the FDA, have notified the Company of a clinical hold in any of its clinical trials. The voluntary pause by the Company was instituted following a recent decrease in the rate of successful manufacturing of ITIL-168, resulting in the inability to dose some patients whose individual product of ITIL-168 was not successfully manufactured.

A pre-specified safety analysis in the DELTA-1 trial has been conducted on patients who received ITIL-168 and did not identify any unexpected safety issues. The Company has commenced an end-to-end analysis of its manufacturing processes and upon completion of this analysis, plans to take corrective actions to improve the rate of manufacturing success and resume the study. In addition, the Company announced that it has voluntarily paused enrollment in DELTA-2, the Company's Phase 1 study of ITIL-168 with pembrolizumab in patients with solid tumors.

Although no manufacturing failures have been observed to date in the ongoing Phase 1 trial of ITIL-306, the Company has also voluntarily paused enrollment in this trial as part of its overall manufacturing analysis. The Company intends to provide an update on the manufacturing analysis by early First Quarter 2023.