Neuroendocrine Tumors
Conditions
Keywords
Neuroendocrine Tumors, [⁶⁸Ga]Ga-DLL3 Nanobody, DLL3 expression, Comparative Study
Brief summary
This study is testing a new PET/CT scan that uses a special tracer called \[⁶⁸Ga\]Ga-DLL3 nanobody to see if it can better detect cancer spread (metastases) in people with neuroendocrine tumors than the standard scans currently used (FDG PET/CT or PSMA PET/CT). DLL3 is a protein found on the surface of many neuroendocrine tumor cells, and the new tracer is designed to stick to this protein, making tumors visible on the scan. The goal is to find out whether this new imaging method can give doctors more accurate information about where the cancer has spread and help them choose the most appropriate treatment for each patient. The study is prospective, multi-center, and self-controlled, meaning each participant will receive both the new scan and the standard scan, allowing a direct side-by-side comparison in the same person. Depending on the type of neuroendocrine tumor, participants will be assigned to one of two groups: one group will be compared with FDG PET/CT and the other with PSMA PET/CT. The two scans will be performed within two weeks of each other, and all images will be read by independent experts who do not know the patient's clinical history, to ensure objective and unbiased results. The investigators plan to enroll about 180-200 patients aged 18 or older who have confirmed neuroendocrine tumors with at least two metastatic sites. The total duration of participation is approximately 6 months, consisting of a screening period of up to 14 days, two imaging scans completed within 2 days, and a final follow-up visit at 6 months to evaluate participants' health and disease progression. Participation is entirely voluntary, and participants may withdraw at any time without affecting participants' standard medical care.
Interventions
DRUG68Ga-PFD3
\[⁶⁸Ga\]Ga-PFD3 is a novel PET tracer constructed by conjugating a DLL3-specific nanobody (single-domain antibody, \~15 kDa) with a chelator for ⁶⁸Ga radiolabeling. DLL3 (Delta-like ligand 3) is a cell-surface protein that is rarely expressed in healthy adult tissues but is overexpressed in over 80% of small cell lung cancer and in other high-grade neuroendocrine tumors, making it an attractive target for molecular imaging. The nanobody platform offers advantages over conventional monoclonal antibody-based tracers (e.g., \[⁸⁹Zr\]Zr-DFO-SC16.56): smaller size (\~15 kDa vs. \~150 kDa) enables superior tissue penetration, rapid blood clearance, and shorter in vivo residence time, allowing same-day PET/CT imaging within hours post-injection. Participants receive a single intravenous injection of \[⁶⁸Ga\]Ga-PFD3 (activity: 111-185 MBq; protein mass and molar activity controlled per protocol), followed by whole-body PET/CT acquisition at approximately 2 hours post-injection. Images are acquired from
Sponsors
Tingting Yuan
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Age ≥ 18 and ≤ 80 years at the time of signing the informed consent form, male or female. * Histologically or cytologically confirmed neuroendocrine neoplasms (NENs), including but not limited to small cell lung cancer (SCLC), neuroendocrine prostate cancer (NEPC), gastroenteropancreatic neuroendocrine tumors (GEP-NENs), or other NEN subtypes. * Patients with strong clinical and radiological suspicion of NENs based on imaging (CT/MRI/conventional PET/CT) and clinical presentation. * At least 2 evaluable metastatic lesions (multiple metastases) confirmed by conventional imaging (CT/MRI/PET/CT). * Eastern Cooperative Oncology Group (ECOG) performance status 0-2. Life expectancy \> 3 months. * Voluntarily agrees to participate and provides written informed consent. * Females of childbearing potential and male participants agree to use reliable contraceptive methods for 6 months after the last study drug administration. * Willing and able to comply with scheduled visits, diagnostic procedures, clinical laboratory tests, and other study procedures.
Exclusion criteria
* Known severe immediate-type hypersensitivity or anaphylactic reaction to DLL3-targeted tracers, nanobody proteins, chelators, buffer components, or excipients. * Pregnant or breastfeeding women. * Estimated glomerular filtration rate (eGFR) \< 30 mL/min/1.73m². * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 3 × upper limit of normal (ULN). * Total bilirubin \> 1.5 × ULN. * Inability to tolerate or cooperate with PET/CT imaging procedures, including but not limited to: severe claustrophobia, inability to remain supine and still for at least 30 minutes, or inability to establish adequate intravenous access. * Received chemotherapy, biological therapy, endocrine therapy, molecular targeted therapy, or investigational drug therapy within 4 weeks prior to enrollment. * Currently participating in another interventional clinical trial. * Prior exposure to any DLL3-targeted therapeutic agent (e.g., Tarlatamab, bispecific T-cell engagers, or DLL3-targeted radioimmunotherapy) or DLL3-targeted radiotracer. * Prior radionuclide therapy or diagnostic scan with an interval of less than 10 physical half-lives of the administered radionuclide prior to study tracer administration. * History of any other malignancy within 5 years prior to screening, except for adequately treated non-melanoma skin cancer, carcinoma in situ of the cervix, or other malignancies with negligible risk of recurrence in the investigator's opinion. * Clinically significant abnormalities on physical examination, electrocardiogram (ECG), or clinical laboratory tests during screening that, in the investigator's opinion, may compromise safety or study compliance. * Any other condition that, in the investigator's opinion, makes the patient unsuitable for study participation (e.g., severe psychiatric disorders, substance abuse, poor compliance).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Diagnostic Accuracy of [⁶⁸Ga]Ga-DLL3 Nanobody PET/CT in Detecting Metastatic Lesions | Baseline (within 14 days of enrollment) and Month 6 | Sensitivity and specificity of \[⁶⁸Ga\]Ga-DLL3 nanobody PET/CT for detecting metastatic lesions in patients with neuroendocrine neoplasms, using a composite reference standard (incorporating histopathology, conventional imaging \[FDG/PSMA PET/CT, diagnostic CT/MRI\], and 6-month clinical/imaging follow-up) as the truth standard. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Lesion Detection Rate | Baseline (within 14 days of enrollment) | Per-lesion detection rate of \[⁶⁸Ga\]Ga-DLL3 PET/CT compared to FDG or PSMA PET/CT, stratified by anatomical location (e.g., liver, bone, lung, brain, lymph nodes). |
| Clinical Management Change Rate | Baseline (at time of image interpretation, within 14 days of enrollment) | Proportion of patients whose clinical management (e.g., staging, treatment selection, or biopsy site decision) is altered based on \[⁶⁸Ga\]Ga-DLL3 PET/CT results compared to conventional imaging. |
| Safety and Tolerability | Up to 24 hours post-injection | Incidence, severity, and causality of adverse events (graded per CTCAE v5.0) following single intravenous injection of \[⁶⁸Ga\]Ga-DLL3 nanobody, including injection site reactions, allergic reactions, and any serious adverse events. |
| Correlation with DLL3 Expression | At study completion (expected at Month 6) | Correlation between \[⁶⁸Ga\]Ga-DLL3 PET/CT uptake (SUVmax, SUVmean) and DLL3 expression level by immunohistochemistry (IHC) in biopsied tumor specimens (where available). |
| Target-to-Background Ratio (TBR) | Baseline (within 14 days of enrollment) | Quantitative comparison of TBR between \[⁶⁸Ga\]Ga-DLL3 PET/CT and standard scans (FDG or PSMA PET/CT) in identified lesions, with background regions pre-defined as liver, blood pool, and muscle. |
Countries
China
Contacts
CONTACTTingting Yuan, MD
Outcome results
None listed