ClinicalTrials.gg
Active, not recruitingNCT03600649Updated Nov 21, 2023

Clinical Trial of SP-2577 (Seclidemstat) in Patients With Relapsed or Refractory Ewing or Ewing-related Sarcomas

A Phase 1 interventional study of Seclidemstat and Cyclophosphamide in Ewing Sarcoma, Myxoid Liposarcoma and Sarcoma,Soft Tissue, sponsored by Salarius Pharmaceuticals, LLC. Active, not recruiting at 16 sites in United States. Open to participants aged 12 Years and older. Per ClinicalTrials.gov, last updated 2023-11-21.

Sponsored by Salarius Pharmaceuticals, LLC · Phase 1, Interventional, and Treatment

From the registry’s dates

  • Primary completion was expected by Sep 2025, 1 year 2 months ago, but the record still lists the study as active, not recruiting.
Phase
Phase 1
Study type
Interventional
Enrollment
50
Allocation
Non-randomized
Ages
12 Years and older
Sex
All
01

Study summary

Single agent, non-randomized, open label expansion in select sarcoma patients including myxoid liposarcoma and other sarcomas that share similar chromosomal translocations to Ewing sarcoma; AND dose expansion of the combination of seclidemstat with topotecan and cyclophosphamide in patients with Ewing sarcoma

Read the detailed description

The single agent expansion cohort of select sarcoma patients will enroll myxoid liposarcoma patients and patients with other sarcomas that share similar chromosomal translocations to Ewing sarcoma (FET-family translocations), including but not limited to desmoplastic small round cell tumor.

A safety lead-in dose escalation and dose expansion will be conducted assessing the combination of seclidemstat with topotecan and cyclophosphamide in patients with relapsed or refractory Ewing sarcoma.

02

Conditions studied

  • Ewing Sarcoma
  • Myxoid Liposarcoma
  • Sarcoma,Soft Tissue
  • Desmoplastic Small Round Cell Tumor
  • Extraskeletal Myxoid Chondrosarcoma
  • Angiomatoid Fibrous Histiocytoma
  • Clear Cell Sarcoma
  • Primary Pulmonary Myxoid Sarcoma
  • Myoepithelial Tumor
  • Sclerosing Epithelioid Fibrosarcoma
  • Fibromyxoid Tumor
03

In context

Sarcoma, Ewing

250 studies on the registry are indexed under Sarcoma, Ewing; 69 are open to participants now.

This study's planned enrollment of 50 is above the median of 36 across 204 interventional studies indexed under Sarcoma, Ewing.

Browse Sarcoma, Ewing studies →

Lead sponsor

Salarius Pharmaceuticals, LLC is the lead sponsor of 4 studies on the registry; 2 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
12 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Age ≥ 12 years and weight ≥ 40 kg.
  • ≥ 70% for over ≥ 16 years old and Lansky ≥ 70% for under 16 years old, equivalent to (ECOG) performance status Grade 0 or 1.
  • of greater than 4 months in investigator's opinion.
  • Willingness to provide tumor during screening and while on treatment. Optional for patients \< 18 years of age and patients enrolled in the Ewing sarcoma combination treatment arm. Biopsies can be exempt if deemed by the investigator that the biopsy is not medically feasible for the patient or the patient is unfit for the procedure.
  • Normal organ and marrow function as defined below:

    • (ANC) ≥ 1.5 x 109/L
    • ≥ 100 x 109/L; no transfusion 7 days prior to labs
    • total ≤ 1.5 x (ULN) or, in patients with Gilbert syndrome, total bilirubin > 1.5 x ULN as long as direct bilirubin is normal
    • and ALT ≤ 3 x ULN
    • creatinine ≤ 1.5 x ULN OR ≥ 60 mL/min/1.73 m2 for patients with creatinine levels above normal
  • Ability to understand and the willingness to sign a written document.

Additional Inclusion Criteria for Ewing Sarcoma Combination Treatment Cohort

  • Patients must have a histologic confirmed diagnosis of Ewing sarcoma with a known EWSR1 translocation through local assessment that is and must have received at least one prior course of therapy for Ewing sarcoma. For the purposes of this study, refractory disease is defined as or unresectable disease that has either progressed or is stable at completion of planned therapy.
  • Patients must have had no more than 2 lines/courses of systemic treatment for Ewing sarcoma
  • No prior therapy with the combination regimen of topotecan and cyclophosphamide. Prior cyclophosphamide is allowed if not combined with topotecan.
  • Patients must have by computed tomography (CT) or magnetic resonance imaging (MRI) based on (RECIST) version 1.1

Additional Inclusion Criteria for Single Agent Myxoid Liposarcoma Cohort and for Single Agent FET-Translocated Sarcomas

  • Patients must have a histologic confirmed diagnosis of one of the following sarcomas that share similar known chromosomal translocations to Ewing sarcoma (per local assessment) and are relapsed or refractory and not amenable to surgery at time of enrollment.
  • Patients must have received at least one prior course of systemic therapy but no more than 3 courses of systemic therapy for sarcoma.
  • Patients must have measurable disease by computed tomography (CT) or magnetic resonance imaging (MRI) based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1

Exclusion criteria

Exclusion Criteria for All Patients

  • Patients who have not recovered to Grade 1 or baseline from adverse events related to prior therapy excluding lymphopenia, alopecia, peripheral neuropathy and ototoxicity, which are only exclusionary if original AE was ≥ Grade 3.
  • Patients receiving therapy with other anti-neoplastic or experimental agents.
  • Prior therapy with LSD1 targeted agents including monoamine oxidases for cancer therapy.
  • Prior oral tyrosine kinase inhibitors (i.e. sorafenib, pazopanib, regorafenib, cabozantanib) within 14 days of Cycle 1 Day 1.
  • Other, prior systemic anti-cancer treatment (chemotherapy or biologic therapy [i.e. monoclonal antibodies]) within 21 days prior to Cycle 1 Day 1. For agents that have known adverse events occurring beyond 21 days after administration, this period must be extended beyond the time during which adverse events are known to occur. The duration of this interval must be discussed with the Medical Monitor.
  • Prior therapy with immunotherapy such as a , cellular therapy or vaccine therapy within 28 days prior to Cycle 1 Day 1. Patients must have recovered from any immune-related adverse events to Grade 1 or baseline and require ≤ 10 mg of prednisone equivalent daily. Patients with immune-related hypothyroidism and/or hypoadrenalism may enroll while on thyroid or hydrocortisone replacement therapy, respectively.
  • Prior small port palliative radiotherapy within 14 days of Cycle 1 Day 1 or within 42 days of Cycle 1 Day 1 from definitive local control radiation (any dose greater than 50 Gy, within 42 days of Cycle 1 Day 1).
  • Prior therapy with long acting myeloid growth factor within 14 days of Cycle 1 Day 1 or within 7 days of Cycle 1 Day 1 from a short acting myeloid growth factor.
  • Evidence of or prior allo- or auto-bone marrow transplant or stem cell infusion within 84 days from Cycle 1 Day 1 or receiving following a stem cell procedure.
  • Participation in a prior study within 30 days prior to Cycle 1 Day 1 or within 5 half-lives of the investigational product, whichever is longer.
  • Progressive or symptomatic ; patients with brain metastases may be included in this trial as long as the brain metastases have received definitive treatment and are stable (i.e., no evidence of progression). The brain metastases must be stable for a minimum of 6 weeks prior to Cycle 1 Day 1.
  • Currently receiving any of the following substances and cannot be discontinued 14 days or 5 half-lives for CYP inhibitors (whichever is shorter) prior to Cycle 1 Day 1:

    • moderate or strong inhibitors or inducers of major CYP isoenzymes, including grapefruit, grapefruit hybrids, pomelos, star fruit, and Seville oranges
    • moderate or strong inhibitors or inducers of major drug transporters
    • substrates of /5 with a narrow therapeutic index
  • Uncontrolled concurrent illness including, but not limited to:

    • ongoing or active infection
    • transfusion dependent thrombocytopenia or anemia
    • psychiatric illness/social situations that would limit compliance with study requirements; discuss with Medical Monitor if there are any questions
  • , uncontrolled heart disease and/or cardiac repolarization abnormality, including any of the following:

    • symptomatic congestive heart failure
    • (LVEF) ≤ 50%
    • unstable angina pectoris or cardiac arrhythmia
    • baseline (Fridericia) ≥ 450 milliseconds
    • long QT syndrome or family history of idiopathic sudden death or congenital long QT syndrome
  • Any major surgery within 21 days prior to Cycle 1 Day 1. Major surgery is defined as any significantly invasive procedure into a major body cavity (abdomen, cranium etc.) and/or surgery requiring extensive recuperation (joint replacement). Please discuss with Medical Monitor if there are any questions.
  • Pregnant and breastfeeding women are excluded from this study. The effects of seclidemstat on the developing human fetus have the potential for teratogenic or abortifacient effects.
  • Men treated or enrolled on this protocol must also agree to use adequate prior to the study, for the duration of study participation, and 4 months after completion of seclidemstat administration.
  • -positive patients on combination antiretroviral therapy are ineligible because of the potential for pharmacokinetic interactions with seclidemstat. In addition, these patients are at increased risk of lethal infections when treated with marrow-suppressive therapy.
Terms in these criteria, in plain language(27)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Karnofsky performance status (KPS)

A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.

Studies often ask for 60 or 70 and above. Your doctor gives the score.

ECOG performance status

A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.

0
Fully active, no restrictions.
1
Limited in strenuous activity, but walking and able to do light work, such as housework or office work.
2
Walking and able to look after yourself, but unable to work; up and about more than half of waking hours.
3
Able to look after yourself only in part; in bed or a chair more than half of waking hours.
4
Unable to look after yourself at all; in bed or a chair all day.

Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.

Life expectancy

The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.

Biopsy and archival tissue

A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.

Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.

Absolute neutrophil count (ANC)

The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.

It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

Bilirubin

A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.

Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.

ULN (upper limit of normal)

The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.

“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.

ALT and AST (liver enzymes)

Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.

Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.

Creatinine clearance (CrCl)

How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Relapsed and refractory

Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.

Metastases

Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.

Measurable disease

The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.

The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.

RECIST

The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.

“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.

CTCAE grade

The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.

1
Mild.
2
Moderate.
3
Severe.
4
Life-threatening.
5
Death due to the event.

“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.

PD-1, PD-L1 and checkpoint inhibitors

PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.

PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.

GVHD (graft-versus-host disease)

After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Brain metastases

Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).

Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.

CYP3A (CYP3A4) inhibitors and inducers

CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.

Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

LVEF (left ventricular ejection fraction)

The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.

QT and QTc

On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.

The study may name a correction formula and a limit in milliseconds, often around 450–480.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

05

Study design

Phase
Phase 1
Primary purpose
Treatment
Allocation
Non-randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
50 participants (estimated)

Study arms

  • Experimental
    Myxoid Liposarcoma

    Twice-daily administration of oral seclidemstat

    Drug: Seclidemstat

  • Experimental
    Sarcomas with FET-family translocations, including demoplastic small round cell tumors

    Twice-daily administration of oral seclidemstat

    Drug: Seclidemstat

  • Experimental
    Ewing sarcoma, combination therapy

    Twice daily administration of seclidemstat in combination with cyclophosphamide and topotecan

    Drug: Seclidemstat · Drug: Cyclophosphamide · Drug: Topotecan

Interventions

  • Twice daily administration of seclidemstat

    Also known as: LSD1 Inhibitor, SP-2577

  • 250 mg/m2/day on Days 1 thru 5 of a 21-day cycle

  • 0.75 mg/m2/day on Days 1 thru 5 of a 21-day cycle

06

What researchers measure

Primary outcomes

  1. Safety and tolerability of seclidemstat (SP-2577) as a single agent and in combination with topotecan and cyclophosphamide measured by dose limiting toxicities and adverse events according to CTCAE version 5.0

    To evaluate the safety and tolerability of seclidemstat (SP-2577) as a single agent and in combination with topotecan and cyclophosphamide in patients with relapsed or refractory Ewing sarcoma and select sarcomas. Toxicities will be graded in severity per the guidelines outlined in the NCI CTCAE version 5.0. The maximum tolerated dose (MTD) is defined as the dose level immediately below the dose level at which ≥ 2 patients from a cohort of 3 to 6 patients experience a dose-limiting toxicity.

    Time frame: From screening through at least 30 days after end of treatment, up to approximately 24 months

Secondary outcomes

  1. Determine the maximum tolerated dose of SP-2577 as determined by dose limiting toxicities measured according to CTCAE version 5.0

    To determine the maximum tolerated dose (MTD) of seclidemstat as a single agent and in combination with topotecan and cyclophosphamide in patients with relapsed or refractory Ewing sarcoma. Toxicities will be graded in severity per the guidelines outlined in the NCI CTCAE version 5.0. The maximum tolerated dose (MTD) is defined as the dose level immediately below the dose level at which ≥ 2 patients from a cohort of 3 to 6 patients experience a dose-limiting toxicity.

    Time frame: From screening through at least 30 days after end of treatment, up to approximately 24 months

  2. Characterization of the pharmacokinetics of SP-2577 as measured by peak plasma concentration

    To characterize pharmacokinetics of seclidemstat as a single agent and in combination with topotecan and cyclophosphamide.

    Time frame: From screening through at least 30 days after end of treatment, up to approximately 24 months

  3. Characterization of the pharmacokinetics of SP-2577 as measured by area under the curve

    To characterize pharmacokinetics of seclidemstat as a single agent and in combination with topotecan and cyclophosphamide.

    Time frame: From screening through at least 30 days after end of treatment, up to approximately 24 months

  4. Characterization of the pharmacokinetics of SP-2577 as measured by apparent clearance of seclidemstat

    To characterize pharmacokinetics of seclidemstat as a single agent and in combination with topotecan and cyclophosphamide.

    Time frame: From screening through at least 30 days after end of treatment, up to approximately 24 months

  5. Characterization of the pharmacokinetics of SP-2577 as measured by median half-life

    To characterize pharmacokinetics of seclidemstat as a single agent and in combination with topotecan and cyclophosphamide.

    Time frame: From screening through at least 30 days after end of treatment, up to approximately 24 months

  6. Food effects on the pharmacokinetics of SP-2577 as measured in both fasted and fed populations, primarily measured by apparent clearance.

    To evaluate the effect of food on the pharmacokinetics of seclidemstat. Both fasted and fed PK samples will be taken.

    Time frame: From screening through at least 30 days after end of treatment, up to approximately 24 months

  7. Anti-tumor activity as measured according to RECIST 1.1 criteria based upon radiological assessments.

    To evaluate the anti-tumor activity of seclidemstat as a single agent and in combination with topotecan and cyclophosphamide. Tumor response will be measured according to RECIST 1.1 criteria. Radiological assessments may be centrally collected and subjected to quality checks and review by a central imaging vendor at the discretion of Salarius.

    Time frame: From screening through at least 30 days after end of treatment, up to approximately 24 months

07

Study locations

16 sites
08

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Jun 2018 (actual). Primary completion is estimated for Sep 2025, 87 months after the start.

Of 41 phase 1 interventional studies under Sarcoma, Ewing, half reached primary completion within 89 months of starting (the median), counting those still running; a quarter within 65 and three quarters within 134. This study's planned 87 months is close to that.

How these figures are worked out, and which studies are left out of them.

Registered
Jun 4, 2018
First posted
Jul 26, 2018
StartActual
Jun 4, 2018
Primary completionEst.
Sep 2025
CompletionEst.
Dec 2025
Last update
Nov 21, 2023
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Nov 21, 2023, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT03600649
Lead sponsor
Salarius Pharmaceuticals, LLC
Collaborators
National Pediatric Cancer Foundation
Responsible party
Sponsor
First posted
Jul 26, 2018
Start date
Jun 4, 2018
Primary completion
Sep 2025 (estimated)
Completion
Dec 2025 (estimated)
Last update
Nov 21, 2023

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is active, not recruiting, as verified in Nov 2023. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Studies of the drug tested here: Seclidemstat

Start the discussion