NEW YORK – Salarius Pharmaceuticals announced it is expanding an ongoing Phase I/II trial of seclidemstat in Ewing sarcoma to include patients with other types of sarcomas with translocations involving the FET family of proteins.
Ewing sarcoma is a bone or soft tissue tumor that mainly occurs in children and young adults, and is caused by a chromosomal translocation that fuses a FET family protein (encoded by FUS, EWSR1 and TAF15 genes) with an ETS family protein, resulting in an altered transcription factor.
Currently, the Phase I/II dose-finding trial for LSD1 inhibitor seclidemstat includes patients with relapsed or refractory Ewing sarcoma and aims to characterize the initial safety profile, pharmacokinetics, and maximum tolerated dose of the drug. Once the maximum tolerated dose is established, the trial will enroll up to 20 Ewing sarcoma patients for additional safety and preliminary efficacy analysis.
The planned expansion now enables 30 patients with other sarcomas with similar gene rearrangements to partake in the study, including myxoid liposarcoma, desmoplastic small round cell tumors, or other Ewing-related sarcomas.
"Preclinical data and early clinical observations involving seclidemstat suggest that the drug may have applicability in several sarcomas that share key characteristics of Ewing sarcoma," Damon Reed, director of the adolescent and young adult program at the Moffitt Cancer Center and principal investigator of the Phase I/II clinical trial, said in a statement. "Based on this potential, and the pressing need for better treatment options for sarcomas, including Ewing sarcoma, we are pleased to extend the ongoing … trial to additional sarcoma subtypes."
Salarius decided to expand enrollment in the study after a Ewing sarcoma patient experienced an 80 percent reduction in prospectively defined target lesions after six months of treatment with seclidemstat. Although, after eight weeks this patient's non-target lesions started to grow based on RECIST criteria, the company said in a statement that the extensive reduction of target lesions, representing the patient's largest tumors, suggests preliminary activity of the drug and supports expansion of the Phase I/II study to other Ewing sarcoma-like cancers.
Salarius is also conducting a second Phase I/II dose-escalation trial investigating seclidemstat in advanced solid tumors.