Novel Targeted Radiotherapy in Pediatric Patients With Inoperable Relapsed or Refractory HGG

March 16, 2026 updated by: Cellectar Biosciences, Inc.

A Phase 1b, Open-Label, Study of a Novel Targeted Radiotherapy in Children, Adolescents and Young Adults With Inoperable Relapsed or Refractory High-Grade Glioma

The purpose of this dose finding study is to evaluate the safety and efficacy of 2 different dose levels of CLR 131 in children, adolescents and young adults with relapsed or refractory high-grade glioma (HGG).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

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

This study is designed to further evaluate the safety and tolerability of CLR 131 at the selected doses in children, adolescents and young adults with relapsed or refractory malignant high-grade glioma. It will also determine the therapeutic activity defined as progression free survival and overall survival, antitumor activity (treatment response) defined as the reduction in tumor volume and identify the recommended Phase 2/3 dose of CLR 131 in children, adolescents and young adults with relapsed or refractory HGG.

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.
50

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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5G 1X8
        • Hospital for Sick Children
  • United States
    • California
      • Palo Alto, California, United States, 94304
        • Stanford University
    • New York
      • New York, New York, United States, 10065
        • Memorial Sloan Kettering Cancer Center
    • Ohio
      • Cincinnati, Ohio, United States, 45229
        • Cincinnati Children's Hospital Medical Center
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Children's Hospital of Philadelphia
    • Texas
      • Dallas, Texas, United States, 75390
        • UT Southwestern Medical Center
      • Houston, Texas, United States, 77030
        • Texas Children's Cancer Center, Baylor College of Medicine
    • Wisconsin
      • Madison, Wisconsin, United States, 53705
        • University of Wisconsin, Carbone Cancer Center

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

2 years to 25 years (Child, Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Previously confirmed (histologically or cytologically) high grade glioma that is clinically or radiographically suspected to be relapsed, refractory, or recurrent
  • ≥ 10 years of age and ≤ 25 years of age at time of consent/assent
  • If ≥ age 16 years, Karnofsky performance status of ≥ 60. If < age 16 years, Lansky performance status ≥ 60
  • Platelets ≥ 75,000/μL (last transfusion, if any, must be at least 1 week prior to study registration, and, unless deemed medically necessary, no transfusions are allowed between registration and dosing)
  • Absolute neutrophil count ≥ 750/μL
  • Hemoglobin ≥ 8 g/dL (last transfusion must be at least 1 week prior to study registration, and, unless deemed medically necessary, no transfusions are allowed between registration and dosing)
  • Using the bedside Schwartz formula, estimated GFR (creatinine clearance) > 60 ml/min/1.73m2
  • Alanine aminotransferase < 3 × ULN
  • Bilirubin < 2 × ULN
  • At least 1 measurable intracranial lesion with longest diameter of at least 10 mm on any imaging sequence.
  • Patients with previously known neurological deficits must be clinically stable at time of enrollment and able to complete all study related procedures. Patients with documented or newly diagnosed neurological deficits will be enrolled at the investigator's discretion.
  • If patient receives steroids for neurological symptom control, the dose must be stable (unchanged for three weeks prior to registration) or on a steroid tapering regimen. Initiation of steroids per routine care immediately prior to CLR 131 dosing is acceptable
  • Patient or his or her legal representative is judged by the Investigator to have the initiative and means to be compliant with the protocol.
  • Patient or his or her legal representative has the ability to read, understand, and provide written informed consent for the initiation of any study-related procedures.
  • Female patients of childbearing potential must have a negative pregnancy test at screening and within 24 hours of dosing. It is recommended that female caregivers of childbearing potential have a negative pregnancy test within one week of dosing.
  • Patients of childbearing potential must practice an effective method of birth control while participating on this study to avoid possible harm to the fetus.

Exclusion Criteria:

  • Antitumor therapy or investigational therapy, within 3-half-lives of the agent preceding the present study. For certain types of radiation (craniospinal, total abdominal, whole lung [spot irradiation to skull-based metastases is not considered craniospinal radiation for the purposes of this study]), at least 3 months must have elapsed. Palliative focal radiation to non-target lesions should be completed at least 2 weeks prior to dosing. Patients participating in non-interventional clinical trials (i.e., non-drug) are allowed to participate in this trial
  • History of hypersensitivity to thyroid protection medication (e.g., potassium iodide, Lugol's solution, etc.)
  • Any other concomitant serious illness or organ system dysfunction (including cardiac and pulmonary dysfunction) that in the opinion of the Investigator would either compromise patient safety or interfere with the evaluation of the safety of the test drug.
  • Major surgery within 6 weeks of enrollment unless delay in therapy poses unacceptable risk to the patient due to clinical progression (enrollment o such patients should be discussed with Medical Monitor)
  • Known history of human immunodeficiency virus or uncontrolled, serious, active infection
  • Pregnancy or breast-feeding

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: Pediatric High-Grade Glioma Patients
Two dosing cohorts will be explored; patients in the first arm will receive two doses, 20 mCi/m2 each, separated by 14 days for two cycles, with a third optional cycle. Patients in the second arm will receive two doses, 10 mCi/m2 each, separated by 14 days for three cycles with a fourth optional cycle.
Drug: CLR 131
CLR 131 will be administered IV (intravenously) at a dose based on patients' BSA
Other Names:
  • iopofosine I 131

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
Safety Evaluation of CLR 131
Time Frame: Assessed throughout the study to 1-year post-infusion follow-up period
Will be assessed by physical examination, performance status, vital signs, laboratory changes over time, and adverse events. Evaluations will use a nonparametric Wilcoxon Signed Rank test and a linear mixed effects modeling will be conducted to evaluate longitudinal changes.
Assessed throughout the study to 1-year post-infusion follow-up period
Efficacy Evaluation for Progression Free Survival
Time Frame: Day 84 post-infusion follow-up period through 3 years following completion of treatment.
To determine the therapeutic activity defined as Progression Free Survival (PFS) using Kaplan Meier estimator. PFS is defined as the time from arm assignment until disease progression or death.
Day 84 post-infusion follow-up period through 3 years following completion of treatment.

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
Tumor Response to CLR 131
Time Frame: 4 hours post-infusion and concluding 4 weeks post-initial imaging
Determine the tumor uptake of CLR 131 and utility of SPECT/CT as a potential diagnostic for response. Images will be reconstructed using quantitative SPECT reconstruction methods with compensation for attenuation, scatter and the full collimator-detector response including septal penetration and scatter. A registered CT image will be used as the attenuation map for the SPECT images. Image data will be converted to activity per cubic centimeters using a sensitivity measurement made using a point source in air.
4 hours post-infusion and concluding 4 weeks post-initial imaging
Treatment Response of CLR 131
Time Frame: From date of arm assignment until date of first documented progression or date of death from any cause, whichever comes first, assessed up to 48 months.
Determine antitumor activity (treatment response) defined as the reduction in tumor volume, measured by MRI scans acquired as FLAIR images and based on the RAPNO criteria for responses.
From date of arm assignment until date of first documented progression or date of death from any cause, whichever comes first, assessed up to 48 months.
Dose Determination for CLR 131
Time Frame: From date of arm assignment until date of first documented progression or date of death from any cause, whichever comes first, assessed up to 48 months.
Identify the recommended Phase 2/3 dose of CLR 131 in relapsed pHGG patients based on both safety and efficacy assessments as defined by the primary endpoints concluded from this study.
From date of arm assignment until date of first documented progression or date of death from any cause, whichever comes first, assessed up to 48 months.
Dosimetry Evaluation for Total Body and Organ
Time Frame: 4 hours post-infusion and concluding 4 weeks post-initial imaging
To determine total body and organ dosimetry, together, of CLR 131 in relapsed pHGG patients, measured by conjugate planar whole-body imaging and/or blood collection drawn for radiologic dosimetry analysis for a subset of patients. Organ time/activity integrals will be entered into OLINDA/EXM software to produce total body and organ dosimetry values for CLR 131.
4 hours post-infusion and concluding 4 weeks post-initial imaging

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.
Cellectar Biosciences, Inc.

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Cancer Institute (NCI)

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.
  • Study Director: Jarrod Longcor, Chief Operating Officer

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 (Actual)

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.
October 1, 2023

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.
May 1, 2026

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.
September 1, 2026

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).
October 28, 2022

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.
November 3, 2022

First Posted (Actual)

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.
November 9, 2022

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.
March 18, 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.
March 16, 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.
March 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.
  • DCL-17-001-pHGG
  • 13460625 (Other Grant/Funding Number: NCI)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The IPD will be made available upon request of NCI, the funding agency partner. This has not yet been decided.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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