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Iopofosine I 131

Phase 3

Waldenstrom Macroglobulinaemia | Small molecule | Oncology |Cellectar Biosciences, Inc.|Last Updated: Aug 14, 2026

Target and mechanism

ModalitySmall molecule

Also known as Iopofosine I 131 single dose

Success Probability

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Market & Valuation

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Trial Design

RandomizedACTIVE_CONTROLLEDDMC
Total Trials1
Total Enrollment219

FDA Designations

ACCELERATED_APPROVALORPHAN_DRUGRARE_PEDIATRIC_DISEASEFAST_TRACKBREAKTHROUGH_THERAPY

Clinical trial landscape

Iopofosine I 131 · 2 trials · 6 indications

Phase 3 1Phase 1 1
NCT07766421Evaluation of Iopofosine I 131 vs. R-CD in WM PatientsWaldenstrom Macroglobulinaemia
NOT YET_RECRUITING219 Analytics
PHASE3NOT YET_RECRUITING
Evaluation of Iopofosine I 131 vs. R-CD in WM Patients
Waldenstrom MacroglobulinaemiaUnlock trial analytics

Study Endpoints

Primary Endpoints

Superiority of progression free survival (PFS)
From baseline randomization through study completion of progressive disease, or death due to any reason (whichever status is recorded first).

A survival analysis will be performed comparing treatment arms using the Cox Proportional Hazard model to determine the hazard ratio, corresponding 95% CI, and p-value to determine superiority between iopofosine I 131 and R-CD.

Dose Determination for CLR 125
57 days after initiation of last cycle (each cycle is 57 days)

Identify the recommended Phase 2 dose and regimen of CLR 125 in advanced TNBC patients

Number of adverse events related to study treatment (CLR 125)
Assessed throughout the study through 1 year following completion of treatment.

Adverse Events are graded per NCI CTCAE v5.0

Secondary Endpoints

Major response rate (MRR)
Day 1 of Cycle 1 of dosing through the start of new antineoplastic treatment or early termination, whichever occurs first.
Overall response rate (ORR)
Day 1 of Cycle 1 of dosing until start of new antineoplastic treatment or early termination, whichever occurs first.
VGPR/CR rates
Day 1 of Cycle 1 of dosing until the start of new antineoplastic treatment or early termination, whichever occurs first.
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Iopofosine I 131EXPERIMENTALIopofosine I 131
R-CDACTIVE_COMPARATORRituximab, cyclophosphamide, dexamethasone
Dosimetry PhaseOTHERIopofosine I 131 (CLR 131) will be administered at 10 mCi on day 1 for approximately 15 patients for imaging purposes.
Treatment Phase: CLR 125 Arm 1EXPERIMENTALCLR 125 administered at 65 mCi/m2 fractionated over four doses (day 1, 2, 8, and 9) in each 8-week cycle; patient will receive up to 4 cycles.
Treatment Phase: CLR 125 Arm 2EXPERIMENTALCLR 125 will be administered at 125 mCi/m2 fractionated over four doses (day 1, 2, 8, and 9) in each 8-week cycle; patient will receive up to 3 cycles.
Treatment Phase: CLR 125 Arm 3EXPERIMENTALCLR 125 will be administered at 190 mCi/m2 fractionated over four doses (day 1, 2, 8, and 9) in each 8-week cycle; patient will receive up to 2 cycles.

Interventions

NameTypeDescription
Iopofosine I 131DRUGFractionated dose
Rituximab (active comparator)DRUGRituximab
CyclophosphamateDRUGCyclophosphamide
DexamethasoneDRUGDexamethasone
CLR 125DRUGInvestigational radiopharmaceutical product intended for IV administration.
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo

Inclusion Criteria: * Histologically and serologically confirmed diagnosis of WM. * Received at least one prior therapy for WM. * Received treatment with a BTKi (including covalent BTKi or non-covalent BTKi). * Symptomatic disease progression requiring therapy. Specifically, participant must meet o...

Countries:United States
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Recent Changes (Last 90 Days)

LOWAug 14, 2026NCT07766421NEW_TRIAL: changed
LOWAug 14, 2026NCT07766421NEW_TRIAL: changed

Frequently asked questions about Iopofosine I 131

What is Iopofosine I 131 used for?

Iopofosine I 131 is an investigational small molecule being studied for the treatment of Waldenstrom Macroglobulinemia and Breast Cancer. It is in clinical development for these oncology indications, with trials evaluating its safety and efficacy in patients with these conditions.

What does Iopofosine I 131 target?

Iopofosine I 131 is a radiolabeled small molecule that delivers iodine-131 to cancer cells. It is designed to target and treat B-cell malignancies, including Waldenstrom Macroglobulinemia, by delivering radiation directly to the tumor cells.

Who makes Iopofosine I 131?

Iopofosine I 131 is being developed by Cellectar Biosciences, Inc., a biopharmaceutical company traded on the NASDAQ under the ticker symbol CLRB. The company is conducting clinical trials to evaluate the drug's safety and efficacy in various oncology indications.

What phase is Iopofosine I 131 in?

Iopofosine I 131 is in Phase 1 clinical development. It has received FDA designations including Accelerated Approval, Orphan Drug, Rare Pediatric Disease, Fast Track, and Breakthrough Therapy. The drug is investigational and not yet approved for commercial use.

What clinical trials is Iopofosine I 131 in?

Iopofosine I 131 is being studied in multiple clinical trials. NCT02952508 is a Phase 2 study in select B-cell malignancies including Waldenstrom Macroglobulinemia. NCT07311993 is a Phase 1 study in triple negative breast cancer. NCT07766421 is a Phase 3 study comparing Iopofosine I 131 to R-CD in Waldenstrom Macroglobulinemia patients.

Is Iopofosine I 131 the same as CLR 125?

No, Iopofosine I 131 is not the same as CLR 125. Iopofosine I 131 is being studied in Waldenstrom Macroglobulinemia and other B-cell malignancies, while CLR 125 is a separate investigational drug being evaluated in a Phase 1 trial for triple negative breast cancer.