⁶⁸Ga- OncoACP3 is an innovative small-molecule radiotracer designed for the non-invasive detection and staging of metastatic prostate cancer. It exhibits ultra-high affinity for Acid Phosphatase 3 (ACP3), an enzyme abundantly expressed in prostate cancer tissues but largely absent in normal organs, except for the healthy prostate. This selective expression makes ACP3 an excellent target for imaging agents when paired with Gallium-68 (⁶⁸Ga).

In contrast, Prostate-Specific Membrane Antigen (PSMA) has been the traditional biomarker for prostate cancer imaging. While PSMA is overexpressed in most prostate cancers, it is also present in other tissues, which can lead to non-specific uptake and potential false positives. Studies have demonstrated that ACP3 is more abundantly expressed in prostate cancer tissues than PSMA, with minimal presence in normal organs. This differential expression suggests that ACP3-targeted imaging could provide clearer and more accurate diagnostic results.

OncoACP3 is also being explored as a theranostic agent when conjugated with therapeutic radioisotopes such as Lutetium-177 (¹⁷⁷Lu) and Actinium-225 (²²⁵Ac).

Preclinical evaluations of OncoACP3 have shown promising results. The radiotracer exhibits rapid and selective accumulation in tumor masses with exceptionally low uptake in normal organs, including the kidneys and salivary glands. This selective targeting enhances image clarity and reduces background noise, facilitating more precise tumor localization.

Moreover, OncoACP3 has demonstrated best-in-class performance both in vitro and in vivo, with the highest reported affinity to the ACP3 antigen. In mouse models bearing ACP3-positive tumors, OncoACP3 achieved significant tumor accumulation and retention, with minimal uptake in non-target tissues. These characteristics suggest that OncoACP3 could offer superior imaging capabilities compared to PSMA-based agents, potentially leading to improved detection and staging of prostate cancer.

Clinical trial.