Safety, Biodistribution, Dosimetry of 68Ga-NYM215 PET/CT and Head-to-head Comparison With 68Ga-DOTATATE PET/CT in Patients With Neuroendocrine Neoplasms: A Prospective Study

Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplasms that frequently overexpress somatostatin receptors (SSTRs), particularly SSTR subtype 2 (SSTR2), which provide specific targets for both imaging and therapy. As a somatostatin receptor agonist, 68Ga-DOTATATE PET/CT is an established imaging modality for the detection, staging, restaging, and treatment selection of patients with NETs.

SSTR antagonists may show lower physiologic uptake in abdominal organs and have demonstrated potential for improved lesion detection compared with SSTR agonists. 68Ga-NYM215 is a novel SSTR antagonist with high receptor affinity. In preclinical SSTR-positive animal models, 68Ga-NYM215 demonstrated favorable safety, biodistribution, and tumor uptake.The purpose of this study is to investigate the biodistribution, safety, and diagnostic ability of 68Ga-NYM215 in patients with NETs. And compare the diagnostic ability of 68Ga-NYM215 with 68Ga-DOTATATE PET/CT.

This prospective study will enroll patients with pathologically confirmed NENs. All participants will undergo both 68Ga-NYM215 PET/CT and 68Ga-DOTATATE PET/CT. For radiation dosimetry, the first 8 participants will undergo serial 68Ga-NYM215 PET imaging at 5, 15, 30, 45, 60, and 120 minutes after 68Ga-NYM215 administration. Subsequent participants will undergo whole-body 68Ga-NYM215 PET/CT at 40 to 60 minutes after administration. All participants will undergo whole-body 68Ga-DOTATATE PET/CT at 40 to 60 minutes after radiotracer administration. The two PET/CT examinations will be performed within 1 week, with an interval of at least 24 hours to minimize potential cross-interference.

Results were determined by two nuclear medicine physicians through consensus, with disagreements adjudicated through concurrent image interpretation involving a third senior physician. For each examination, lesions will be documented according to number, anatomical location, size, SUVmax, and tumor-to-background ratio (TBR).

The study will explore the safety, biodistribution, radiation dosimetry, and diagnostic performance of 68Ga-NYM215 PET/CT. A head-to-head comparison with 68Ga-DOTATATE PET/CT will be performed to compare the diagnostic performance at both the patient and lesion levels.