This is a first-in-human study evaluating the suitability of [203Pb]VMT01 for SPECT/CT imaging and [68Ga]VMT02 for PET/CT imaging of MC1R-expressing metastatic melanoma. Study results will provide foundational data to develop imaging and dosing for future therapeutic trials of [212Pb]VMT01 for the treatment of metastatic melanoma.~The study will be a cross-over study with the participants serving as their own comparator. Participants with positive FDG-PET scans for stage IV (or inoperable stage III) metastatic melanoma will undergo SPECT/CT scans utilizing [203Pb]VMT01 followed a few weeks later by PET/CT scans utilizing [68Ga]VMT02, or vice versa. The order of the imaging agents will be randomly assigned.
The study hypothesis is that new imaging agents [203Pb]VMT01 and [68Ga]VMT02 can be safely used in humans without independent biological effect and can be used to image melanoma tumors expressing the melanocortin sub-type 1 receptor (MC1R) by SPECT/CT and PET/CT imaging modalities respectively.