Salarius lead candidate is in nine U.S. trial sites

Dan Sfera
4 min readAug 4, 2021


Answers for Cancer

Salarius Pharmaceuticals, Inc., a clinical-stage biopharmaceutical company focusing on the development of drugs targeting rare, orphan cancers and cancers with a high unmet need, has added Fox Chase Cancer Center Center in Philadelphia to its ongoing trial of seclidemstat as a treatment for Ewing Sarcoma and FET-Rearranged Sarcomas. The Houston-based company, which was founded in 2014, now has nine U.S. clinical trial sites participating in the open label trial intended to assess seclidemstat at the recommended Phase 2 dose (RP2D).

Fox Chase Cancer Center has been added as an active trial site for the dose-expansion stage of the ongoing clinical trial evaluating the company’s lead drug candidate, seclidemstat. Patient recruitment is now underway at all sites, and the first patients in the dose-expansion stage of the clinical trial have been dosed. The Hospital of Fox Chase Cancer Center and its affiliates (collectively “Fox Chase Cancer Center”), a member of the Temple University Health System, is one of the leading cancer research and treatment centers in the United States. Founded in 1904 in Philadelphia as one of the nation’s first cancer hospitals, Fox Chase was also among the first institutions to be designated a National Cancer Institute Comprehensive Cancer Center in 1974. The recently founded Cancer Epigenetics Institute is a national hub for epigenetics study and collaboration focused on mechanisms promoting cancer and therapeutic resistance.

Salarius’ lead molecule, Seclidemstat, is a novel, oral, reversible inhibitor of lysine-specific histone demethylase 1 (LSD1), an enzyme that has been shown to play a key role in the development and progression of several cancers. Seclidemstat has received Fast Track Designation, Orphan Drug Designation and Rare Pediatric Disease Designation for Ewing sarcoma from the U.S. Food and Drug Administration.

Per the amended protocol, the trial’s dose-expansion stage now includes three patient arms. The first arm will enroll up to 30 patients with Ewing sarcoma, a rare and deadly pediatric bone cancer, and will investigate seclidemstat in combination with topotecan and cyclophosphamide, a commonly used second- and third- line chemotherapy regimen. Salarius believes data released during ASCO 2021 demonstrated synergy in an Ewing sarcoma cell line when seclidemstat was used in combination with

topotecan and cyclophosphamide. Salarius believes this treatment combination and its use as a secondand third-line therapy could greatly expand the addressable patient population for seclidemstat and improve outcomes by allowing physicians to use seclidemstat earlier in the Ewing sarcoma continuum of care.

The trial’s second patient arm will investigate seclidemstat as a single agent in up to 15 patients with myxoid liposarcoma. The third patient arm will investigate seclidemstat as a single agent in up to 15 patients with select sarcomas that share a biology similar to Ewing sarcoma, also referred to as FETrearranged or Ewing-related sarcomas. In data released at ASCO 2021, a subset of patients with advanced FET-rearranged sarcomas treated with single-agent seclidemstat resulted in stable disease (SD) and prolonged time to progression (TTP) which Salarius believes suggests disease control, a clinically relevant endpoint for soft tissue sarcomas.

All patient arms are designed to evaluate safety and efficacy endpoints in patients with advanced disease. Salarius expects to report data in 2022 and provide earlier updates if possible.

Johnathan Whetstine, Ph.D., Director, Cancer Epigenetics Institute, Fox Chase Cancer Center, and a consultant to Salarius, said, “We are excited to be working with Salarius and look forward to exploring the potential of seclidemstat and its ability to inhibit the LSD1 enzyme. Based on our extensive research into the epigenetic causes of cancer, we believe LSD1 inhibition holds great promise in the treatment of many cancers. We believe data from preclinical studies using Ewing sarcoma cell lines has demonstrated the molecule’s ability to hit two aspects of the enzyme simultaneously. This, added to clinical data showing drug activity across Ewing and other sarcomas, support the further exploration of seclidemstat in these high unmet need patient populations.”

David Arthur, CEO of Salarius Pharmaceuticals, explained, “Our goal is to make a difference in the lives of patients fighting cancer, and we believe the data we have released to date has been compelling. To now be working with a cancer research center of the caliber of Fox Chase Cancer Center further affirms the potential of seclidemstat to have a meaningful impact on the treatment of Ewing sarcoma and other cancers. We look forward to providing additional updates throughout 2021.”

In addition to Fox Chase, active clinical trial site locations include, Johns Hopkins All Children’s Hospital in St. Petersburg, FL; Children’s Hospital of Los Angeles in Los Angeles, CA; Moffitt Cancer Center in Tampa, FL; Dana-Farber Cancer Institute in Boston, MA; MD Anderson Cancer Center in Houston, TX; Nationwide Children’s Hospital in Columbus, OH; Memorial Sloan Kettering Cancer Center in New York City; and the Sarcoma Oncology Center in Santa Monica, CA.

Salarius is currently enrolling patients for a phase 1 trial in advanced solid tumors. This trial is enrolling patients with advanced solid tumors who have progressed on prior therapy, for example patients with prostate, breast, ovarian, lung and other cancers. Depending on the cancer, LSD1 can associate with a myriad of proteins to drive tumor growth. For instance, in prostate cancer LSD1 can associate with the androgen receptor to activate genes that promote cancer cell growth and metastasis. Seclidemstat is able to block these interactions and reduce tumor burden.

Salarius is also developing seclidemstat for several cancers with high unmet medical need, with a second Phase 1/2 clinical study in advanced solid tumors, including prostate, breast, and ovarian cancers. The Salarius LSD1 technology was licensed from the University of Utah Huntsman Cancer Institute where it was developed in the laboratory of Dr. Sunil Sharma. In 2016, Salarius was granted a $18.7 million Product Development Award from the Cancer Prevention and Research Institute of Texas (CPRIT), of which approximately $11.8 million remains available to Salarius. This funding, which does not dilute investor equity holdings, has enabled the company to move its programs forward. In addition, the National Pediatric Cancer Foundation (NPCF) provides financial support funding the ompany’s Ewing sarcoma clinical trial. This NPCF funding also does not dilute investor equity holdings.