[Phase 2 clinical study of 123I-N-(2-diethylaminoethyl)-2-iodobenzamide in the diagnostic of primary and metastatic ocular melanoma].

Purpose: Iodobenzamides are reported to possess an affinity for melanoma. A first selected compound, BZA, was studied in a phase 2 clinical trial on 159 patients as an imaging agent for the detection of primary melanoma and metastases with good results. We report the results of a second phase 2 clinical trial on 40 patients with a new radiopharmaceutical BZA2 (an orthoiodinated BZA analog), which was expected to provide quality images sooner after injection and with better imaging contrast.
Patients and Methods: Performance was evaluated in 40 patients classified with primary ocular lesions (12), suspicion of metastases of ocular or cutaneous origin (15), or with no known secondary lesion (13), and results were compared with conventional investigation techniques (ophthalmoscopy, ultrasonography, and angiography for ocular melanoma, whole-body CT scan and ultrasonography for metastases).
Results: No adverse events were recorded. The overall results on a per patient basis showed a sensitivity of 78% and a specificity of 95%. The four false negatives observed were ocular lesions (three with a thickness<3mm and one achromic), but all the proven secondary lesions were imaged. Moreover, negative BZA2 scintigraphy in cases of suspicious lesions led to the correction of two diagnoses: the prostatic origin of bone metastases and the endocrine tumor origin (APUD system) of an ocular lesion.
Discussion: BZA2 scintigraphy is an easy test with good tolerance. In the diagnosis of ocular primary melanoma, the sensitivity of the test is 64%, although limited by the thickness (3mm) and the pigmentation of the lesion. However, the BZA2 scintigraphy is a very useful test for the detection of melanoma metastases, with a sensitivity of 100% and a specificity of 95%.
Conclusion: BZA2 scintigraphy showed good tolerance in patients and it appears promising for differential diagnosis, staging, and restaging of melanoma.