Radioiodinated N-[3-(4-morpholino)propyl]-N-methyl-2-hydroxy-5-iodo-3-methylbenzylamine (ERC9) : a new potential melanoma imaging agent

The role of nuclear medicine in the management of patients with malignant melanoma has expanded in recent years with the introduction of lymphoscintigraphy and sentinel lymph node biopsy, intense interest in positron emission tomography (PET) imaging using 2-[18F]fluoro-2-deoxyglucose (18F-FDG) as a tracer, and encouraging reports of several new single-photon-emitting radiopharmaceuticals. While PET imaging with FDG exhibits a high sensitivity for imaging patients with melanoma, specificity may not be as high and access to the technology remains limited. Single-photon emission tomography (SPET) imaging remains standard technology for most nuclear medicine departments. We report a novel radiopharmaceutical--radioiodinated N-[3-(4-morpholino)-propyl]-N-methyl-2-hydroxy-5-iodo-3-methylbenzylamine (ERC9)--which appears to show a sensitivity and specificity that are commensurate with expectations of a radiopharmaceutical for routine clinical imaging. In this phase II trial, 110 patients at risk for recurrence, with suspected recurrence or being restaged have been imaged with this novel tracer, demonstrating an overall sensitivity of 91% and specificity of 89%. The results of our study support a phase III trial to establish the clinical role of ERC9 in staging melanoma patients at presentation who are at high risk for metastasis, or restaging patients with known relapse to assess the extent of their disease, particularly if therapy or enrollment into a clinical trial is being considered.