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PSMA and Beyond 2026: Initial Experience with APC3

(UroToday.com) The 2026 PSMA & Beyond conference featured a developing novel radioligands session and presentation by Dr. Philipp Backhaus discussing the initial experience with APC3. The history of ACP3 goes back to 1950 when it was established as a biomarker, which led to the discovery of PSA in 1970 and its establishment as a biomarker in the early 1980s. Fast forward to the early 2010s when sipuleucel-T was FDA approved for metastatic castration resistant prostate cancer (mCRPC),1 and then to 2024 when OncoACP3 was discovered:

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In late 2025, Dr. Backhaus’ group2 reported the first translational and first in human PET targeting prostatic acid phosphatase using 68Ga-OncoACP3-DOTA. This study analyzed and matched 68Ga-OncoACP3-DOTA and 18F-PSMA-1007 PET scans in a cohort of 25 patients with prostate cancer, comparing the biodistribution and tumor uptake of the two tracers. 68Ga-OncoACP3-DOTA showed low background uptake, including in the salivary glands and kidneys, with a significant difference from the high 18F-PSMA-1007 PET uptake in these organs (p < 0.002). Overall, SUVmax in localized or metastatic prostate cancer did not significantly differ between the two tracers:

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Better 68Ga-OncoACP3-DOTA performance was observed in 11 of 25 matched scan pairs, and better 18F-PSMA-1007 PET performance was noted in 8 of 25 matched pairs:

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First in human 177Lu-OncoACP3 DOTA has been performed in several patients, which Dr. Backhaus presented as unpublished data.

Presented by: Philipp Backhaus, University of Münster, Münster, Germany

Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2026 PSMA & Beyond Conference, Los Angeles, CA, Thurs, Mar 26 – Fri, Mar 27, 2026. 

References:

  1. Kantoff PW, Higano CS, Shore ND, et al. Sipuleucel-T immunotherapy for castration-resistant prostate cancer. N Engl J Med 2010;363(5):411-422.
  2. Backhaus P, Cazzamalli S, Oehler O, et al. Translational and first-in-human positron emission tomography targeting prostatic acid phosphatase in prostate cancer using the ligand [68Ga]Ga-OncoACP3-DOTA. Eur Urol. 2026 Apr;89(4):305-310.