Safety and Diagnostic Efficacy of 177Lu-AF03 in Patients With Solid Tumors

This study evaluates 177Lu-AF03, a bispecific heterodimeric peptide targeting both FAP and integrin αvβ6, for safety, biodistribution, radiation dosimetry, and preliminary diagnostic efficacy in patients with malignant solid tumors. Preclinical studies showed enhanced tumor uptake, prolonged retention, and low uptake in non-target organs. Eight patients with confirmed malignant solid tumors will receive a single intravenous injection of 177Lu-AF03, followed by SPECT/CT imaging at multiple time points. Safety will be monitored until Day 7 post-injection.

Inclusion Criteria: * Patients who voluntarily provide written informed consent prior to any study-specific procedure. * Patients with histologically (or cytologically) confirmed malignant solid tumors, treatment-naïve, with at least one measurable lesion (target lesion). * Age ≥18 and ≤75 years, male or female. * ECOG performance status 0 or 1. * Life expectancy ≥6 months. * Women of childbearing potential must have a negative pregnancy test, and all participants (including male participants) must agree to use effective contraception during the study and for at least 3 months after dosing. Exclusion Criteria: * Pregnant or lactating women, or women planning to become pregnant during the study or within 3 months after dosing (except those who are at least 1 year postmenopausal or surgically sterile \[e.g., bilateral tubal ligation without reversal, bilateral oophorectomy, or hysterectomy\]); or participants planning to donate sperm or oocytes during the study or within 3 months after dosing. * Known or suspected hypersensitivity to the investigational drug or any of its components. * Receipt of another investigational product at enrollment, or within 5 half-lives of that product or 30 days after its last dose, whichever is longer. * Use of any radiotherapeutic agent within 90 days before dosing, or any diagnostic radionuclide within 3 days before dosing. * Significant hepatic or renal impairment: total bilirubin (TBIL) \>1.5×ULN, or aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) \>2.5×ULN, or serum creatinine \>1.5×ULN. * Active infection at screening. * Inability to remain still and supine in the scanner for at least 30 min during SPECT, or claustrophobia or other conditions that preclude cooperation with SPECT. * Any other condition that, in the investigator's judgment, makes the participant unsuitable for this study.