RARE Daily

FDA Lifts Partial Clinical Hold on Salarius Pharmaceuticals Phase 1/2 Clinical Trial in Ewing Sarcoma

May 10, 2023

FDA Lifts Partial Clinical Hold on Salarius Pharmaceuticals Phase 1/2 Clinical Trial in Ewing Sarcoma

Rare Daily Staff

The U.S. Food and Drug Administration lifted a partial clinical hold on Salarius’ phase 1/2 trial of its experimental therapy seclidemstat to treat patients with Ewing sarcoma.

In October 2022, the company paused enrollment in the study after a patient in the trial died and the company reported a suspected unexpected serious adverse reaction to the FDA. The company continued to treat patients already receiving the drug.

Seclidemstat, Salarius’ lead candidate, is being studied as a potential treatment for pediatric cancers, sarcomas, and other cancers with limited treatment options.

Seclidemstat is a differentiated inhibitor of the LSD1 enzyme, a well-validated target for both hematological and solid tumors. It inhibits LSD1’s demethylation and scaffolding properties, representing a viable therapeutic option for patients who need it the most. The FDA granted Salarius fast track, orphan drug and rare pediatric disease designations for seclidemstat in Ewing sarcoma. Salarius is also exploring seclidemstat’s potential in several cancers with high unmet medical need. The company has received financial support from the National Pediatric Cancer Foundation to advance the Ewing sarcoma clinical program.

“We are confident in seclidemstat’s ability to improve the lives of patients with Ewing sarcoma and are delighted the FDA has removed the partial clinical hold,” said David Arthur, president and CEO of Salarius. “The FDA’s decision to remove the clinical hold puts us back on track to engage in dialogue with the FDA on various topics relating to further clinical development of seclidemstat and possible registration pathways. As we gain clarity in those discussions, we intend to provide updates to our investors.”

In December 2022 Salarius reported interim clinical results from its phase 1/2 trial showing that treatment with seclidemstat in combination with topotecan and cyclophosphamide had 60 percent confirmed disease control and 7.4 months median time to tumor progression for Ewing sarcoma first-relapse patients. The results also suggest that first- and second-relapse Ewing sarcoma patients treated with seclidemstat in combination with topotecan and cyclophosphamide who achieve disease control may have an increased time to tumor progression compared with treatment of topotecan and cyclophosphamide alone, per published data from the phase 3 rEECur study.

The phase 1/2 trial is now in its dose-expansion stage with one arm planned to enroll up to 30 patients with Ewing sarcoma, a rare and deadly pediatric bone cancer, that will investigate seclidemstat in combination with topotecan and cyclophosphamide, a commonly used second- and third-line chemotherapy regimen.

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