177Lu-CTR-FAPI for the Treatment of Thyroid Cancer

Inclusion Criteria:

* Histologically confirmed diagnosis of thyroid cancer according to the 2022 WHO classification of thyroid tumors. Differentiated thyroid carcinoma must be diagnosed as radioactive iodine-refractory (RAIR) by a nuclear medicine specialist.
* Evidence of progressive disease based on RECIST 1.1 criteria in pre-treatment imaging.
* Prior surgical resection of resectable cervical lesions, with currently unresectable systemic disease.
* Previous targeted therapy was discontinued due to intolerance, or lack of benefit from targeted therapy assessed by investigator, or patient refusal.
* At least one measurable target metastatic lesion on contrast-enhanced CT/MRI (longest diameter of lesion ≥ 10 mm or shortest diameter of lymph node ≥ 15 mm).
* Positive CTR-FAPI uptake in lesions, defined as SUVmax \> 10 in more than half of the lesions on 68Ga-CTR-FAPI PET/CT.
* Life expectancy \> 6 months.
* ECOG performance status ≤ 2.
* Prior anti-tumor therapy-related toxicities that recoverd to Grade 0 or 1 (except alopecia, pigmentation, or chronic radiation toxicities and deemed irreversible by the investigator).
* For subjects with fertility: agreement to use effective contraception during treatment and 4 months (males) or 7 months (females) after the last dose.
* Voluntary participation and signed informed consent.

Exclusion Criteria:

* Presence of CTR-FAPI-negative lesions (i.e., malignant lesions on contrast-enhanced CT/MRI without uptake on 68Ga-CTR-FAPI PET/CT).
* Prior therapeutic radionuclide therapy (except 131I).
* Systemic anti-cancer therapy (including chemotherapy, targeted therapy, immunotherapy, radionuclide therapy, or anti-tumor traditional Chinese medicine) within 4 weeks before the first dose.
* Participation in another drug or device clinical trial within 4 weeks before the first dose.
* Insufficient major organ function.
* Severe or uncontrolled comorbidities.
* Presence of pleural effusion or ascites requiring intervention or judged uncontrolled by the investigator at screening.
* Active infection within 4 weeks before the first dose.
* Women who are pregnant, breastfeeding, or planning pregnancy.
* Known allergy to contrast agents.
* History of symptomatic central nervous system metastases.
* Other concurrent malignancies.
* Surgery under general anesthesia within 8 weeks before the first dose.
* History of acute coronary syndrome or stroke within 8 weeks before the first dose.
* Severe claustrophobia.
* Any other condition deemed inappropriate for participation by the investigator (e.g., poor compliance, inability to cooperate with treatment and follow-up).