Study of Diagnostic Performance of [18F]CTT1057 for PSMA-positive Tumors Detection

Phase II/III Study for Evaluation of the Diagnostic Performance of [18F]CTT1057 PET Imaging for the Detection of PSMA Positive Tumors Using Histopathology as a Standard of Truth

The purpose of this study was to evaluate the diagnostic performance of [18F]CTT1057 as a PET imaging agent for detection and localization of PSMA positive tumors using histopathology as Standard of Truth (SoT). Tissue specimens from both the primary tumor and pelvic lymph nodes dissected during surgery from patients with newly-diagnosed high-risk prostate cancer (PCa) were used for the histopathology assessments.

This was a multi-center, single-arm, open-label prospective study to evaluate the diagnostic performance of vidoflufolastat (18F) as a positron emission tomography (PET) imaging agent for detection and localization of prostate specific membrane antigen (PSMA) positive tumors, using histopathology as standard of truth (SoT). in newly diagnosed high-risk prostate cancer (PCa) patients.

A total of 195 participants were enrolled to ensure that at least 156 participants were evaluable for the co-primary endpoints. Surgery was performed after vidoflufolastat (18F) positron emission tomography/computerized tomography (PET/CT) scan.

The co-primary endpoints of patient-level sensitivity and region-level specificity were assessed by comparing the central reading results of the vidoflufolastat (18F) PET/CT scan to the local histopathology results in the dissected tissue specimens, i.e. both the primary tumor and the dissected Pelvic Lymph Nodes (PLNs).

Inclusion Criteria:

• Untreated high risk biopsy-proven PCa patients according to D'Amico classification (Stage ≥ T2c or PSA level >20ng/ml or Gleason score ≥8) (D'Amico et al 1998)
• Scheduled or planned radical prostatectomy and extended pelvic lymph node resection up to 6 weeks after the investigational PET/CT scan followed by histopathology assessment
• ECOG performance status 0-2
• Signed informed consent must be obtained prior to participation in the study
• Participants must be adults ≥ 18 years of age

Exclusion Criteria:

• Inability to complete the needed investigational and standard-of-care imaging examinations due to any reason (severe claustrophobia, inability to lie still for the entire imaging time, etc.)
• Any additional medical condition, serious intercurrent illness, concomitant cancer or other extenuating circumstance that, in the opinion of the Investigator, would indicate a significant risk to safety or impair study participation, including, but not limited to, current severe urinary incontinence, hydronephrosis, severe voiding dysfunction, need of indwelling/condom catheters, New York Heart Association class III or IV congestive heart failure, history of congenital prolonged QT syndrome, uncontrolled infection, active hepatitis B or C, and COVID-19.
• Known allergy, hypersensitivity, or intolerance to [18F]CTT1057
• Prior and current use of PSMA targeted therapies
• Prior and current treatment with any ADT (first or second generation), including LHRH analogues (agonists or antagonists)
• Any 5-alpha reductase inhibitors within 30 days before screening
• Patients with small cell or neuroendocrine PCa in more than 50% of biopsy tissue
• Patients with incidental PCa after transurethral resection
• Use of other investigational drugs within 30 days before screening