A Study of SGT-53 in Children With Refractory or Recurrent Solid Tumors

May 4, 2026 updated by: SynerGene Therapeutics, Inc.

A Phase I Study of SGT-53, a TfRscFv-Liposome-p53 Complex, in Children With Refractory or Recurrent Solid Tumors

The purpose of this study is to determine the dose limiting toxicities and recommended phase 2 dose of SGT-53 alone and in combination with topotecan and cyclophosphamide in pediatric patients with recurrent or refractory solid tumors.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Suspended

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The p53 is a vital human tumor suppressor gene. Loss of p53 suppressor function is present in the majority of human cancers. The p53 protein has a diverse range of functions including regulation of cell cycle checkpoints, cell death (apoptosis), senescence, DNA repair, maintenance of genomic integrity, and control of angiogenesis. Abnormalities of the p53 gene may impact the efficacy of standard anticancer treatments such as radiation and chemotherapy. P53 mutation and pathway dysfunction are associated with poor clinical outcomes and the presence of the p53 mutation correlates with resistance to chemotherapy and radiation. The development of somatic gene therapy has created the potential to restore wild type function of p53. SGT-53 is a complex of cationic liposome encapsulating a normal human wild type p53 DNA sequence in a plasmid backbone. This complex has been shown to efficiently and specifically deliver the p53 cDNA to the tumor cells. Introduction of the p53 cDNA sequence is expected to restore wtp53 function in the apoptotic pathway. P53 restoration has been shown most effective in enhancing cytotoxicity in combination with an agent which results in DNA damage or initiates apoptosis. Though mutated p53 is uncommon in childhood cancer, children with adrenocortical tumor and rhabdomyosarcoma have been found to have p53 mutations. Additionally, wild type p53 may be suppressed in tumors through pathway crosstalk. For example, in sarcomas, a common childhood solid tumor, activation of MDM2 effectively inactivates p53. Thus, the treatment proposed in this trial to reintroduce p53 may offer benefit even in patients with p53 wild-type tumors. Moreover, the SGT-53 treatment can significantly sensitize pediatric cancer cell lines to the killing effect of the standard chemotherapeutic agents, topotecan and cyclophosphamide. Thus, we propose to assess the efficacy of this combination therapy in pediatric patients with refractory or recurrent solid tumors. This phase I clinical trial is to determine the dose limiting toxicities (DLT), recommended phase 2 dose, and maximum tolerated dose (MTD) of SGT-53 (if reached) alone and in combination with conventional chemotherapy in pediatric patients with recurrent or refractory solid tumors. In addition, pharmacokinetics of escalating doses of SGT-53 is studied.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
18

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Texas
      • Houston, Texas, United States, 77030
        • Texas Children's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

1 year to 21 years (Child, Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • All patients and/or their parents or legally authorized representatives must sign a written informed consent.
  • Patients must be > than 12 months and ≤ 21 years of age at the time of study enrollment.
  • Body surface Area (For Dose Level -1): Patients must be ≥ 0.38 m² at the time of study enrollment.
  • Patients with relapsed or refractory solid tumors (excluding primary central nervous system tumors) are eligible. Patients must have had histologic verification of malignancy at original diagnosis or relapse.
  • Patients must have either measurable or evaluable disease.
  • Patient's current disease state must be one for which there is no known curative therapy or therapy proven to prolong survival with an acceptable quality of life.
  • Karnofsky ≥ 50% for patients > 16 years of age and Lansky ≥ 50 for patients ≤ 16 years of age.

  • Patients must have fully recovered from the acute toxic effects of all prior anti-cancer chemotherapy:

    • At least 21 days after the last dose of myelosuppressive chemotherapy (42 days if prior nitrosourea).
    • At least 14 days after the last dose of a long-acting growth factor (e.g. Neulasta) or 7 days for short-acting growth factor.
    • At least 7 days after the last dose of a biologic agent.
    • At least 42 days after the completion of any type of immunotherapy, e.g. tumor vaccines.
    • At least 3 half-lives of the antibody after the last dose of a monoclonal antibody.
    • At least 14 days after local palliative XRT (small port); At least 150 days must have elapsed if prior TBI, craniospinal XRT or if ≥ 50% radiation of pelvis; At least 42 days must have elapsed if other substantial bone marrow radiation.
    • No evidence of active graft vs. host disease and at least 84 days must have elapsed after transplant or stem cell infusion.
    • Patient must not have had prior exposure to gene vector delivery products within 3 months.
    • Patients may not have had prior SGT-53. Patient who have received prior topotecan, cyclophosphamide, or both are eligible.

  • Adequate Bone Marrow Function:

    • Peripheral absolute neutrophil count (ANC) ≥ 1000/mm³.
    • Platelet count ≥ 100,000/mm³.

  • Adequate Renal Function:

    • Creatinine clearance or radioisotope GFR ≥ 70ml/min/1.73 m² OR age/gender appropriate serum creatinine.

  • Adequate Liver Function:

    • Bilirubin (sum of conjugated + unconjugated) ≤ 1.5 x upper limit of normal (ULN) for age.
    • SGPT (ALT) ≤ 110 U/L.
    • Serum albumin ≥ 2 g/dL.

Exclusion Criteria:

  • Are pregnant or breast-feeding women.

  • Concomitant medications:

    • Patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment are not eligible.
    • Patients who are currently receiving another investigational drug are not eligible.
    • Patients who are currently receiving other anti-cancer agents are not eligible.
    • Patients who are receiving cyclosporine, tacrolimus or other agents to prevent graft-versus-host disease post bone marrow transplant are not eligible for this trial.
  • Patients who have an uncontrolled infection are not eligible.
  • Patients who have received a solid organ transplantation are not eligible.
  • Patients who in the opinion of the investigator may not be able to comply with the safety monitoring requirements of the study are not eligible.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: SGT-53 with Topotecan/Cyclophosphamide
There will be 4-6 cycles (21 days/cycle) of therapy in this trial. In cycle 1, SGT-53 will be given as a single agent twice weekly starting at 1.4 mg/m² of DNA per infusion to evaluate single-agent toxicity. Pharmacokinetic studies will be performed. In the absence of dose limiting toxicity, patients will proceed to cycle 2 even if they have progressive disease. Starting in cycle 2, SGT-53 will be administered twice-weekly in combination with topotecan and cyclophosphamide administered daily for 5 days, days 1-5 of each cycle. Day 1 of each combination cycle is the first day on which topotecan and cyclophosphamide are administered with SGT-53. If a subject has at least stable disease after four cycles of therapy and is tolerating protocol therapy, two additional cycles may be considered.
Genetic: SGT-53
The starting dose of SGT-53 will be 1.4 mg DNA/m² (dose level 1). If MTD is reached at dose level 1, subsequent cohort will be treated at 0.7 mg DNA/m² (dose level -1). If MTD is not reached at 2.1 mg DNA/m² (dose level 2), additional dose level(s) may be added. Intra-patient escalation is not allowed. Topotecan/cyclophosphamide will not be administered in cycle 1. In cycle 2, SGT-53 will be administered in combination with 0.6 mg/m² topotecan and 200 mg/m² cyclophosphamide IV daily for 5 days. Beginning in cycle 3, if no DLTs in cycle 2, topotecan and cyclophosphamide will be escalated to 0.75 mg/m² and 250 mg/m², respectively. No further dose escalation is permitted. If DLT develops at the higher doses, the doses should be decreased back to those in cycle 2.
Drug: Topotecan
Topotecan/cyclophosphamide will not be administered in cycle 1. In cycle 2, 0.6 mg/m² topotecan will be administered in combination with SGT-53 and cyclophosphamide IV daily for 5 days. Beginning in cycle 3, if no DLTs in cycle 2, topotecan will be escalated to 0.75 mg/m². No further dose escalation is permitted. If DLT develops at the higher doses, the dose should be decreased back to those in cycle 2.
Other Names:
  • Hycamtin
Drug: Cyclophosphamide
Topotecan/cyclophosphamide will not be administered in cycle 1. In cycle 2, 200 mg/m² cyclophosphamide will be administered in combination with topotecan and SGT-53 IV daily for 5 days. Beginning in cycle 3, if no DLTs in cycle 2, cyclophosphamide will be escalated to 250 mg/m². No further dose escalation is permitted. If DLT develops at the higher doses, the dose should be decreased back to those in cycle 2.
Other Names:
  • Cytoxan®
  • Neosar®

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Dose limiting toxicities (DLT)
Time Frame: 3-18 weeks
The dose limiting toxicities of SGT-53 alone and in combination with topotecan and cyclophosphamide in pediatric patients with recurrent or refractory solid tumors will be assessed by any adverse events that are possibly, probably or definitely attributable to study drugs.
3-18 weeks
Recommended phase 2 dose (RP2D)
Time Frame: 3-18 weeks
The recommended phase 2 dose of SGT-53 alone and in combination with topotecan and cyclophosphamide in pediatric patients with recurrent or refractory solid tumors will be assessed.
3-18 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Tolerability of systemic intravenous infusion (assessed by any adverse events related to infusion of study drugs according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0.)
Time Frame: 3-18 weeks
Tolerability of systemic intravenous infusion of SGT-53 alone and in combination with topotecan and cyclophosphamide will be assessed by any adverse events related to infusion of study drugs according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0.
3-18 weeks
Anti-tumor activity (evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) criteria version 1.1.)
Time Frame: 3-18 weeks
Anti-tumor activity of SGT-53 alone and in combination with topotecan and cyclophosphamide will be evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) criteria version 1.1.
3-18 weeks
Concentration of SGT-53 over time will be characterized by Cmax and clearance (Pharmacokinetic will be performed to evaluate the concentration of SGT-53 in patient's blood over time)
Time Frame: 3-18 weeks
Pharmacokinetic will be performed to evaluate the concentration of SGT-53 in patient's blood over time
3-18 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
SynerGene Therapeutics, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Jodi Muscal, MD, Baylor College of Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2014

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 18, 2014

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 29, 2015

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 3, 2015

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 4, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • SGT53-01-2

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