Seclidemstat-Azacitidine Combination Trial for Hematologic Cancers Reopens for Enrollment

Salarius Pharmaceuticals, a clinical-stage biopharmaceutical firm, has reported positive developments in its Phase 1/2 hematologic cancer clinical trial at the University of Texas MD Anderson Cancer Center. The trial, listed on clinical trials.gov as NCT04734990, is actively recruiting participants. Notably, a patient with Ewing sarcoma treated with a combination of seclidemstat, topotecan, and cyclophosphamide (TC) has achieved a partial response, defined by a 30% or greater reduction in the sum of the diameters of the target lesions. This advancement has increased the objective response rate (ORR) to 60% among Ewing sarcoma patients experiencing their first relapse.

The company had engaged Canaccord Genuity, LLC in August 2023 to conduct a strategic review aimed at maximizing shareholder value. Despite these ongoing efforts, Salarius remains committed to its clinical programs. In October 2022, the FDA had imposed a partial clinical hold on the MD Anderson trial due to a suspected unexpected serious adverse reaction (SUSAR) in the FET-rearranged arm of the seclidemstat sarcoma trial. However, no SUSAR has been observed in the MD Anderson trial patients.

Salarius Pharmaceuticals' president and CEO, David Arthur, expressed satisfaction with the FDA's decision to lift the partial clinical hold and the potential for MD Anderson to enroll more patients, thereby expanding the patient data pool. He also highlighted the interim results reported by MDACC researchers as encouraging and anticipated the benefits that higher doses of seclidemstat could bring to patients.

Seclidemstat, an innovative oral inhibitor of the LSD1 enzyme, has received fast track, orphan drug, and rare pediatric disease designations from the FDA for the treatment of Ewing sarcoma. It has been studied in both an MDACC investigator-initiated trial and a company-sponsored Phase 1/2 trial in combination with TC for relapsed/refractory Ewing sarcoma.

Researchers have also reported interim results of a clinical trial combining seclidemstat with azacitidine for treating myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) patients who had relapsed or progressed after hypomethylating agent therapy. Among eight evaluable patients, four showed an objective response, with a 90% probability of survival for 11 months for those receiving the combination treatment.

As of December 2023, the company-sponsored trial has enrolled 13 relapsed Ewing sarcoma patients, including those with first and second relapses, treated with seclidemstat at doses of 600 mg or 900 mg twice daily in combination with TC chemotherapy. The first-relapse patients showed a 60% ORR and a 60% disease control rate (DCR), with some still experiencing disease control and objective responses months after beginning the treatment.

Salarius Pharmaceuticals is dedicated to developing new cancer treatment options, with its lead candidate, seclidemstat, being explored for pediatric cancers, sarcomas, and other cancers with limited treatment options. The company has received support from the National Pediatric Cancer Foundation and a Product Development Award from the Cancer Prevention and Research Institute of Texas (CPRIT).