Foghorn® Therapeutics Inc. announced an update on the FHD-609 program in synovial sarcoma and SMARCB1-deleted tumors. Foghorn is pausing enrollment in the FHD-609 study in synovial sarcoma and SMARCB1-deleted tumors due to a grade 4 QTc prolongation event in a synovial sarcoma patient at the second highest dose. Enrollment of the dose escalation portion of the study has been completed and a maximum tolerated dose has been identified.

Patients in the affected cohort were dose reduced and additional safety measures have been discussed with and provided to the study investigators. The Company promptly communicated the enrollment pause and risk mitigation actions to the FDA and European regulatory authorities. Consequently, the FDA placed the study on partial clinical hold in the United States, while allowing patients currently enrolled and benefiting from therapy to continue dosing and to remain on FHD-609.

The Company is not at this time planning to pursue a dose expansion study independently.