Rationale: Prostate specific membrane antigen (PSMA) is a transmembrane protein, which is expressed on prostate cancers cells and other malignancies. Recently, several ligands have been developed that target PSMA. Linked to Gallium-68, this enables diagnostic 68Ga-PSMA-PET/CT scans. Linked to Lutetium-177 enables therapeutic 177Lu-PSMA Radioligand therapy. Most research on the diagnostic and therapeutic possibilities of PSMA has been conducted in patients with advanced prostate cancer.

This research group investigates whether these findings also apply to salivary gland cancer (SGC), a rare cancer. Previously the investigators conducted a phase II 68Ga-PSMA imaging study (NCT03319641), to evaluate PSMA ligand uptake in locally advanced, recurrent and metastatic (R/M) ACC and SDC (two subtypes of SGC). A relevant PSMA-ligand uptake was observed in 93% of ACC patients and 40% of SDC patients. Therefore we consider 177Lu-PSMA radioligand therapy a potential new treatment option for these subtypes of SGC.

Objective: To evaluate the safety and efficacy of 177Lu-PSMA RLT in patients with R/M ACC and SDC with PSMA ligand uptake.

Study design: Phase II pilot study, single centre, two cohorts.