VEGF-SPECT with In-111-bevacizumab in stage III/IV melanoma patients

Purpose: A feasibility study was performed to investigate the presence of VEGF in melanoma lesions by VEGF-SPECT with In-111-bevacizumab. In addition the effect of a single therapeutic bevacizumab dose on In-111-bevacizumab uptake was compared with VEGF levels in resected melanoma lesions.

Patients and methods: Eligible were patients with stage III/IV melanoma who presented with nodal recurrent disease. VEGF-SPECT was performed after administration of 100 Mbq (111) In-bevacizumab (8 mg) at days 0, 2, 4 and 7 post injection. Tumour visualisation and quantification were compared with CT and FDG-PET. On day 7 a single dose of 7.5 mg/kg bevacizumab was administered intravenously. On day 21, a second tracer dose In-111-bevacizumab was administered and scans were obtained on days 21, 25 and 28. Metastases were surgically resected within 2 weeks after the last VEGF-SPECT scan and immunohistological (IHC) VEGF tumour expression was compared with In-111-bevacizumab tumour uptake.

Results: Nine patients were included. FOG-PET and CT detected both in total 12 nodal lesions which were all visualised by VEGF-SPECT. At baseline, In-111-bevacizumab tumour uptake varied 3-fold between and 1.6 +/- 0.1-fold within patients. After a therapeutic dose of bevacizumab there was a 21 +/- 4% reduction in In-111-bevacizumab uptake. The In-111-bevacizumab tumour uptake in the second series positively correlated with the VEGF-A expression in the resected tumour lesions.

Conclusion: VEGF-SPECT could visualise all known melanoma lesions. A single dose of bevacizumab slightly lowered In-111-bevacizumab uptake. Future studies should elucidate the role of VEGF-SPECT in the selection of patients and the individual dosing of bevacizumab treatment. (C) 2011 Elsevier Ltd. All rights reserved.