Malignancy Detection Rates of [⁶⁸Ga]Ga-SSO120 PET/CT in Patients with Small Cell Lung Cancer and Large Cell...

The primary aim of this study was to investigate the malignancy detection rate of [⁶⁸Ga]Ga-SSO120 ([⁶⁸Ga]Ga-satoreotide trizoxetan) PET/CT in patients with small cell lung cancer (SCLC) and large cell neuroendocrine lung cancer (LCNEC). Secondary aims included investigations of lesion-based detection rates and quantification. Methods: In this prospective, phase 2, cross-sectional imaging trial, 21 [⁶⁸Ga]Ga-SSO120 PET/CTs were performed for 19 patients. Overall detection rates, lesion-based detection rates, and number of identified lesions were compared between [⁶⁸Ga]Ga-SSO120 PET and CT. The [⁶⁸Ga]Ga-SSO120 SUV_max, SUV_peak, SUV_mean, and tumor-to-liver ratios in malignant lesions and selected normal tissue were quantified. Results: Nineteen patients (16 with SCLC, 2 with LCNEC, and 1 with combined SCLC/LCNEC) were scanned during palliation chemotherapy (n = 11) or surveillance (n = 8). [⁶⁸Ga]Ga-SSO120-detectable lesions were identified in 18 patients (95%). Sensitivity in the lungs, regional lymph nodes, and extrathoracic regions was 82%, 83%, and 93%, respectively. [⁶⁸Ga]Ga-SSO120 PET detected significantly fewer lesions than did CT (P = 0.037), particularly small lung lesions, regional lymph nodes, and liver lesions. In contrast, [⁶⁸Ga]Ga-SSO120 PET identified 10 additional metastases in 5 patients (bone, 7; cerebellum, 1; subcutaneous, 2). SUV_max (median, 7.4; range, 4.6-26.4) was not significantly associated with time since diagnosis, time since last chemotherapy, number of treatment cycles, or current progression. Conclusion: [⁶⁸Ga]Ga-SSO120 PET/CT successfully visualized SCLC and LCNEC lesions during and after chemotherapy. Therapeutic studies with [¹⁷⁷Lu]Lu-SSO110 ([¹⁷⁷Lu]Lu-satoreotide tetraxetan), the theranostic companion of [⁶⁸Ga]Ga-SSO120, PET are warranted.