It’s full steam ahead for Salarius Pharmaceuticals after the US Food and Drug Administration (FDA) removed a partial clinical hold on a Phase I/II trial in Ewing sarcoma.

The FDA has allowed Salarius to resume recruitment for a Phase I/II study (NCT03600649) testing its lead candidate seclidemstat in the rare pediatric cancer Ewing sarcoma. Previously, Salarius paused enrollment in October 2022 due to an unexpected patient death, which was classified as a suspected unexpected serious adverse reaction (SUSAR).

Once the partial clinical hold took effect, the already enrolled patients were permitted to continue seclidemstat treatment after consulting with their physician. The investigator-sponsored Phase I/II study has a primary endpoint of safety and tolerability and a target enrollment of 50 subjects.

Ewing sarcoma is a rare cancer that affects bones and soft tissue surrounding bones, primarily in pediatric patients. The FDA has recently emphasised the need to focus on overcoming the challenges in recruiting pediatric patients.

Phase I/II data for Salarius

Two months after the partial clinical hold took effect, Salarius released positive interim data from the Phase I/II study. Among 13 patients with Ewing sarcoma, five achieved confirmed disease control with no tumour progression while treated with seclidemstat in combination with topotecan and cyclophosphamide.

There was also a reported 1.6 month median time to tumour progression, which could offer an advantage over treatment with topotecan and cyclophosphamide. Seclidemstat is a lysine-specific demethylase 1 (LSD-1) inhibitor with FDA Fast Track Designation, Orphan Drug Designation, and Rare Pediatric Disease Designation for Ewing sarcoma.