125I Seed Brachytherapy Combined With Immunotherapy for Primary, Recurrent, or Metastatic Malignant Tumors

ConditionMalignant Tumors

Trial statusNot yet recruiting

Trial phasePhase 2

Trial typeInterventional

Biological sexAll

Age18-80

SponsorLi Min

About this trial

This prospective randomized trial evaluates the efficacy and safety of combining 125I seed interstitial brachytherapy with immune checkpoint inhibitor therapy in patients with primary, recurrent, or metastatic malignant tumors. Immunotherapy has become an important systemic treatment option, yet many patients experience limited benefit due to low tumor immunogenicity, insufficient T-cell infiltration, and an immunosuppressive tumor microenvironment.

125I seed brachytherapy provides continuous low-dose-rate radiation to the tumor, promoting antigen release, enhancing dendritic cell activation, and potentially converting immunologically "cold" tumors into more responsive "hot" lesions. Integrating localized radiation with systemic immunotherapy may improve tumor response, prolong progression-free survival, and reduce recurrence.

Patients will be randomized 1:1 to receive 125I seed implantation plus immunotherapy or immunotherapy alone. The primary endpoints are objective response rate (ORR) and progression-free survival (PFS). Secondary endpoints include failure-free survival (FFS), overall survival (OS), disease control rate (DCR), duration of response (DoR), local control, recurrence rate, adverse events, and quality of life. Exploratory analyses will assess radiomics features, subgroup responses, and different patterns of recurrence. This study aims to determine whether adding 125I seed brachytherapy enhances the clinical benefits of immunotherapy across diverse malignant tumors.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Age 18 to 80 years.

Histologically or clinically confirmed primary, recurrent, or metastatic malignant tumor.

At least one measurable lesion according to RECIST 1.1 or iRECIST.

Tumor site suitable for 125I seed implantation under CT or PET/CT guidance.

Disqualifiers

Prior I-125 seed implantation at the planned treatment site.

Active uncontrolled infection or systemic inflammatory disease.

Known history of autoimmune disease requiring systemic immunosuppression.

Prior treatment with immune checkpoint inhibitors within the last 4 weeks.

Trial design

Design model

Parallel

Treatments tested in this trial

Immune Checkpoint Inhibitors
Drug
Examples include PD-1/PD-L1 inhibitors (e.g., pembrolizumab, nivolumab, camrelizumab, sintilimab) Administered per standard dosing schedule (e.g., every 2-3 weeks)
125I Seed Implantation
Other intervention
PET/CT-guided implantation or CT-guided implantation Dose planning: D90 typically 90-140 Gy (adjusted per tumor type and size) Post-implant dosimetry: D90, V100, V150 recorded
Immune Checkpoint Inhibitors
Drug
Same agent class and dosing schedule as the experimental arm Administered until disease progression, unacceptable toxicity, or study completion

Treatment groups

90 Participants

are divided into 2 treatment groups

Group A: 125I Seed Brachytherapy + ImmunotherapyExperimental treatment 2 interventions

Group B: Immunotherapy AloneActive comparator 1 intervention

Trial outcomes

Primary outcomes

Objective Response Rate (ORR)

Proportion of patients achieving complete response (CR) or partial response (PR) as defined by RECIST 1.1 or iRECIST, assessed via CT/MRI/PET-CT.

Time frame

Every 6-12 weeks, up to 24 months

Progression-Free Survival (PFS)

Time from randomization to radiographic disease progression or death from any cause.

Time frame

Up to 24 months

Secondary outcomes

Failure-Free Survival (FFS)

Time from randomization to the first occurrence of treatment failure, including disease progression, local recurrence, distant metastasis, discontinuation due to adverse events, or death.

Time frame

Up to 24 months

Overall Survival (OS)

Time from randomization to death from any cause.

Time frame

Up to 36 months

Disease Control Rate (DCR)

Percentage of patients achieving CR, PR, or stable disease (SD), according to RECIST 1.1/iRECIST.

Time frame

Every 6-12 weeks, up to 24 months

Duration of Response (DoR)

Time from first documentation of CR/PR until radiographic progression or death.

Time frame

Up to 24 months

Other outcomes

Radiomics Features and Predictive Modeling

Extraction of radiomic features from PET/CT or CT images to explore associations with ORR, PFS, recurrence pattern, and treatment response.

Time frame

Up to 24 months

Subgroup Analyses

Assessment of treatment effect by clinical subgroups (primary vs recurrent vs metastatic disease, tumor type, PD-L1 expression, inflammatory markers).

Time frame

Up to 24 months

Patterns of Failure / Recurrence Patterns

Classification of failure patterns (local, regional, distant) and correlation with dosimetry (D90, V100) and imaging biomarkers.

Time frame

Up to 24 months

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

Li Min

Lead sponsor

Jinan Military General Hospital

Sponsor institution

Source ClinicalTrials.gov

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