Imaging Efficacy of [¹⁸F]CTT1057 PET/CT in Patients with Biochemically Recurrent Prostate Cancer: Results from...

Area of Science:

• Nuclear medicine
• Oncology
• Radiopharmaceutical imaging

Background:

• Improved diagnostic accuracy is crucial for prostate cancer patients experiencing biochemical recurrence (BCR) with low prostate-specific antigen (PSA) levels.
• Prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) is a promising modality for detecting recurrent disease.

Purpose of the Study:

• To evaluate the imaging performance of the novel PSMA-targeted PET radiotracer [18F]CTT1057.
• To assess the ability of [18F]CTT1057 to detect PSMA-positive lesions in patients with prostate cancer at first BCR and low PSA levels.

Main Methods:

• Prospective study (GuidePath; NCT04838613) involving patients with BCR and PSA levels ≥0.2 ng/mL or a PSA increase of ≥2 ng/mL.
• Patients received [18F]CTT1057 and [68Ga]Ga-PSMA-11 for PET/CT imaging.
• Coprimary endpoints: region-level correct localization rate (CLR) and patient-level positive predictive value (PPV) of [18F]CTT1057, compared against a hierarchical composite truth standard (CTS).

Main Results:

• 161 patients were evaluable, with 93.2% experiencing their first BCR and a median baseline PSA of 0.4 ng/mL.
• The study successfully met both coprimary endpoints.
• Region-level CLR ranged from 65.2% to 75.0% (95% CI: 53.4%-62.1%), and patient-level PPV ranged from 64.6% to 76.5% (95% CI: 51.8%-62.5%).

Conclusions:

• [18F]CTT1057 demonstrated high accuracy in detecting PSMA-positive lesions in patients with prostate cancer at first BCR and low PSA levels.
• The radiotracer met predefined thresholds for region-level CLR and patient-level PPV.
• [18F]CTT1057 is a valuable PSMA-targeted PET radiotracer for BCR detection.