Comparative PET Imaging Trial Shows Increased Detection of PCa Recurrence with 64Cu-SAR-bisPSMA

The PET agent ⁶⁴Cu-SAR-bisPSMA significantly bolsters detection of biochemical recurrence of prostate cancer (PCa) in comparison to ⁶⁸Ga-PSMA-11, according to new research to be presented at the European Association of Urology (EAU) Congress March 13-16 in London.

For the phase II Co-PSMA Investigator-Initiated Trial (ITT), researchers compared ⁶⁴Cu-SAR-bisPSMA (Clarity Pharmaceuticals) and ⁶⁸Ga-PSMA-11 in 50 patients who had biochemical recurrence (BCR) of PCa after a radical prostatectomy, according to the study.

The study authors found that next-day imaging with ⁶⁴Cu-SAR-bisPSMA (after the use of ⁶⁸Ga-PSMA-11):

• revealed 63 PCa lesions in comparison to 24 lesions with ⁶⁸Ga-PSMA-11;

• led to positive PET scans in 78 percent of the cohort in contrast to 36 percent of the patients with ⁶⁸Ga-PSMA-11; and

• had a mean per patient lesion amount of 1.26 in comparison to 0.48 for ⁶⁸Ga-PSMA-11.

(Editor’s note: For related content on prostate cancer imaging, click here.)

The researchers also determined that the use of ⁶⁴Cu-SAR-bisPSMA, which garnered an FDA fast track designation for PCa BCR in 2025, facilitated treatment changes in 44 percent of the cohort.

Based on the findings for a cohort with prostate-specific antigen (PSA) levels ranging from 0.2 to 0.75 ng/mL), lead study author Louise Emmett, M.D., suggested that ⁶⁴Cu-SAR-bisPSMA may facilitate earlier detection of PCa recurrence.

“ … More sensitive diagnostics that remain highly specific are needed for effective early intervention in BCR. Our research demonstrates that ⁶⁴Cu-SAR-bisPSMA PET/CT offers a significant advancement in the detection of recurrent prostate cancer. Compared to ⁶⁸Ga-PSMA-11, the 24-hour ⁶⁴Cu-SAR-bisPSMA images identified the site of disease recurrence in a higher proportion of patients, directly informing tailored treatment decisions for men in BCR. These findings highlight the potential for ⁶⁴Cu-SAR-bisPSMA to improve patient outcomes,” posited Dr. Emmett, the director of theranostics and nuclear medicine at St. Vincent’s Hospital in Sydney, Australia.