ANALYSIS OF IRRADIATED MELANOMA CELL LINES AS ANTIGEN SOURCE IN CLINICAL TRIALS. UPDATE OF TWO PHASE I CLINICAL TRIALS AND AN ONGING PHASE II/III CLINICAL TRIAL IN MELANOMA PATIENTS

ANDREA M COPATI ; GABRIELA A. PIZZURRO; LUCIANA M PUJOL-LEREIS; LUIS A. QUESADA-ALLUE; VALERIA J DUZELMAN ; MARIA PAULA ROBERTI; ESTRELLA M LEVY; JEAN-LUC TEILLAUD; MARIA M BARRIO; JOSE MORDOH

Lugano

Congreso; The 11th International Symposium on Dendritic Cells in Fundamental and Clinical Immunology DC2010: Forum on Vaccine Science; 2010

The Institute for Research in Biomedicine (IRB) & The Swiss Vaccine Research Institute

Between 2002 and 2004, a Phase I clinical trial was conducted on 20 patients (pts) with cutaneous melanoma stages IIB (n=2), III (n=10) and IV(n=8), using a vaccine composed of amixture of irradiated melanoma cell lines (Vaccimel), BCG and varying doses of GM-CSF (Barrio M. et al. J. Immunother. 2006, 29: 444-454). With a mean follow-up of 85.4 months, the overall disease – free survival of stage III pts is 72 %. One Stage IIB pt recurred with liver metastases 7 years after vaccination. In that study, the optimal dose of GM-CSF co administered with the vaccine was found tobe 300 - 400 ìg. Based on that trial, we have launched in 2009 a Phase II/III randomized clinical trial on 108 cutaneous melanoma pts with stages IIB, IIC and III comparing CSF-470 (a mixture of four irradiated allogeneic melanoma cell lines) with BCG and GM-CSF versus interferon-alpha.  Moreover, between 2004 and 2006, a Phase I clinical trial comparing different numbers of autologous dendritic cells (DCs) loaded with a mixture of apoptotic/necrotic irradiated allogeneic melanoma cell lines was conducted on 16 pts with cutaneous melanoma, stages IIC (n=1), III (n=8) and IV (n= 7) (von Euw et al, J. Transl. Med. 2008, 6:6). After a mean follow up of 80 months, 80 % of stages IIC and III pts are disease - free. All the stage IV pts have progressed. In an effort to improve the vaccine efficiency, and since the clinical trials described above employed a mixture of irradiated cell lines, we investigated some cellular changes accompanying radiation-induced apoptosis/necrosis of the melanoma cell lines. It was found that after irradiation, a large number of lipid vesicles was formed in melanoma dying cells. Confocal and phase contrast microscope analysis suggested that part of these vesicles are captured by DCs. These lipid vesicles mainly contained triglycerides. We have also found that theMART-1 melanoma antigen was enriched in irradiated apoptotic/necrotic melanoma cells, although it was not associated to lipid bodies. These findings may help to understand the events accompanying DC uptake of tumor antigens.