(UroToday.com) The 2025 SNMMI annual meeting featured a prostate cancer and molecular imaging session and a presentation by Dr. Jiarou Wang discussing the first human study of 68Ga-P17-079 in prostate cancer. Drugs targeting PSMA have played a significant role in the treatment of prostate cancer.
However, for patients with extensive bone metastases, PSMA single-target therapies show limited efficacy. Therefore, previous research developed dual-agent targeting both PSMA and bisphosphonate. This study, presented at the SNMMI annual meeting, aimed to evaluate the preliminary safety of 68Ga-P17-079 in humans, as well as its biodistribution and kinetic characteristics.
A total of three prostate cancer patients with bone metastases were enrolled in this study. All patients underwent 68Ga-PSMA-11 PET/CT imaging first, followed by 90-minute dynamic imaging with 68Ga-P17-079 PET/CT within one week:
During the dynamic imaging, radiotracer uptake in lesions and organs was measured at multiple time points. The results of the 3-month follow-up were evaluated using the CTCAE 5.0 criteria to assess potential side effects.
In the three patients, no side effects were observed during the 3-month follow-up. A comparison of organ uptake at 60 minutes revealed that 68Ga-P17-079 PET/CT exhibited significantly lower uptake in the salivary glands (SUVmean 3.69 ± 1.39 versus 9.65 ± 3.34, P = 0.0152) and kidneys (SUVmean 10.07 ± 1.18 versus 32.65 ± 4.42, p < 0.0001) compared to 68Ga-PSMA-11 PET/CT:
Dynamic imaging demonstrated that the uptake of 68Ga-P17-079 in organs remained consistently low, while the tumor-to-blood pool ratio showed early and marked uptake, progressively increasing over time:
In soft tissue metastases, the tumor-to-blood pool ratios at different time points were: 10 min 2.88 ± 1.55, 15 min 3.46 ± 1.82, 20 min 4.17 ± 2.11, 30 min 5.02 ± 2.68, 40 min 5.89 ± 3.03, 60 min 6.64 ± 3.55, 90 min 8.83 ± 4.69. In bone metastases, the ratios were 10 min: 4.65 ± 3.29, 15 min 5.45 ± 3.66, 20 min 5.66 ± 3.65, 30 min 6.54 ± 4.37, 40 min 8.20 ± 5.46, 60 min 8.31 ± 5.48, 90 min 10.45 ± 7.12:
Dr. Wang concluded this presentation discussing the first human study of 68Ga-P17-079 in prostate cancer with the following take home points:
- Preliminary human studies of 68Ga-P17-079 have demonstrated its safety, with low uptake in organs and high uptake in both soft tissue and bone metastases, which increases over time
- Its biodistribution and dynamic characteristics suggest that this imaging agent has the potential to serve as an effective theranostic drug
Presented by: Jiarou Wang, Peking Union Medical College Hospital, Beijing, China
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the Society of Nuclear Medicine and Molecular Imaging (SNMMI) 2025 Annual Meeting, New Orleans, LA, Sat, Jun 21 – Tues, Jun 24, 2025.