SP-2577 Granted Fast Track Designation by the FDA for Patients with Ewing Sarcoma

The drug is currently the subject of an ongoing phase I/II clinical study for the treatment of patients with Ewing sarcoma who have relapsed or are refractory to standard-of-care therapy.

SP-2577 (Seclidemstat) has been granted fast track designation by the FDA for the treatment of patients with Ewing sarcoma who have relapsed or are refractory to standard-of-care therapy, according to Salarius Pharmaceuticals, the drug’s developer.1

A potent reversible LSD1 inhibitor, SP-2577 is the subject of an ongoing phase I/II clinical study.

“Ewing sarcoma is a rare and deadly bone cancer that most often strikes children and young adults and for which there are no targeted therapies approved. Seclidemstat has demonstrated a potential to address this considerable unmet need, and we look forward to rapidly advancing its development so that it soon may be available to those patients most in need,” Damon Reed, MD, Director of the Adolescent and Young Adult Program at the Moffitt Cancer Center and principle investigator for the clinical trial, said in a press release.

Salarius began enrolling for the phase I trial in Ewing sarcoma in 2018 and is currently still recruiting.2 The open label, non-randomized, single arm study will utilize an accelerated dose escalation, followed by a conventional 3+3 dose escalation phase to achieve maximum tolerated dose.

SP-2577 is orally administered twice-daily. Translocations involving the EWS gene are the sole driver for over 85% of Ewing sarcoma, and the EW protein must complex with LSD1 to induce a cancer phenotype.3 SP-2577 blocks the LSD1-EWS interaction to reverse cancer pathology, which has resulted in cures in animal models.

Being a reversible inhibitor, SP-2577 could potentially offer more efficacy, more flexible dosing, and less toxicity. Salarius expects to release early cohort data from the study in early 2020.

“Securing FDA Fast Track Designation for Seclidemstat in Ewing sarcoma is an achievement for Salarius in the ongoing development of the drug and recognition that there is an unmet need to bring much needed hope to patients and their families suffering through this devastating disease. Coupled with Seclidemstat’s previously granted orphan drug designation and rare pediatric disease designation by the FDA, we feel well positioned to take advantage of the FDA’s expedited programs for drug development and review,” David Arthur, president and CEO of Salarius, said in a press release.

Ewing sarcoma is a devastating pediatric illness and represents a major unmet clinical need, according to Salarius. There is a 70-90% five-year mortality rate for patients whose tumors recur after treatment or who are initially diagnosed with metastatic cancer. As of now, chemotherapy, radiation, and tumor resection surgery are the only options for patients. 

1. Salarius Pharmaceuticals Receives FDA Fast Track Designation for Lead Drug Candidate, Seclidemstat, in Relapsed or Refractory Ewing Sarcoma [news release]. Houston, Texas. Published December 16, 2019. globenewswire.com/news-release/2019/12/16/1960915/0/en/Salarius-Pharmaceuticals-Receives-FDA-Fast-Track-Designation-for-Lead-Drug-Candidate-Seclidemstat-in-Relapsed-or-Refractory-Ewing-Sarcoma.html. Accessed December 16, 2019.
2. ClinicalTrials.gov. Clinical Trial of SP-2577 (Seclidemstat) in Patients With Relapsed or Refractory Ewing Sarcoma. ClinicalTrials.gov website. Published November 5, 2019. clinicaltrials.gov/ct2/show/NCT03600649?term=SP-2577&cond=Ewing+sarcoma&draw=2&rank=1. Accessed December 16, 2019.
3. Salarius Pharmaceuticals. Salarius’ lead molecule, Seclidemstat, is a reversible LSDA inhibitor. Seclidemstat inhibits LSD1’s demethylation and scaffolding properties, representing a viable therapeutic option for patients who need it the most. Salarius Pharmaceuticals website. Published 2019. salariuspharma.com/our-programs/pipeline/. Accessed December 16, 2019.