Vaccination of melanoma patients with dendritic cells loaded with a mixture of allogeneic apoptotic/necrotic melanoma cells: A phase I clinical study

ERIKA M. VON EUW; MARÍA M. BARRIO; DAVID FURMAN; ESTRELLA MARIEL LEVY; MICHELE BIANCHINI; ALEJANDRA VELLICE; ABRAHAM KOHAN; ROSA WAINSTOK DE CALMANOVICHI; MATÍAS CHACÓN; JULIO KAPLAN; JOSÉ MORDOH

Los Angeles

Congreso; 2007 AACR Annual Meeting; 2007

In a Phase I study to evaluate safety and immune responses, 16 melanoma patients (pts) (1 stage IIC, 7 stage III and 8 stage IV) were treated with a vaccine composed of autologous dendritic cells (DCs) loaded with a mixture of four apoptotic/necrotic allogeneic melanoma cell lines (Apo-Nec). One stage IV patient was withdrawn from the protocol due to rapid progression. PBMC were obtained by leukaferesis, monocytes were adhered to plastic flasks and cultured in the presence of GM-CSF and IL-4 in serum-free medium. Immature DCs (iDCs) (95.1 } 3.6% CD11c+/CD14-, 70 } 4.8% CD1a+) were loaded with ƒÁ-irradiated apoptotic/necrotic melanoma cells in a 3:1 ratio for 48 hs and injected id without adjuvants. Each patient received four vaccines two weeks apart, in cohorts of four pts receiving 5, 10, 15, or 20 x106 DC/Apo-Nec per vaccine.The vaccine was well tolerated in all pts. Toxicity of DC/Apo-Nec was mild and consisted of local reactions in some pts; the dose-limiting number of DC/Apo-Nec cells has not been reached. We found that 42.3 } 13.7% of iDCs were able to phagocyte Apo-Nec cells and that phagocytosis induced DCs maturation as evidenced by increased expression of CD80, CD83, CD86, HLA I, HLA II and CD40, as compared to iDCs. Also, after phagocytosis, 75.2 } 16% reduction in Dextran-FITC endocytosis was observed. CCR7 was upregulated upon Apo-Nec phagocytosis in DCs from all pts and, accordingly, DC/Apo-Nec cells were able to migrate in vitro towards MIP-3ƒÀ but not to MIP-1ƒ¿. Melanoma pts´ DCs matured in response to LPS equally as DCs from healthy donors. A positive DTH reaction was observed in all pts after DC/Apo-Nec vaccination. The presence of CD8+T lymphocytes specific to gp100 and MelanA/MART-1 Ags was studied by tetramers binding in HLA-A*0201 pts (7/15) before and after vaccination, being found that 2/7 pts increased their specific T lymphocytes after vaccination. Also, pre- and post-vaccination PBMCs from five HLA-A*0201+ pts were tested for peptide-specific IFN-ƒÁ release by ELISPOT. The frequency of anti-MART-1 and anti-gp100 specific CD8+T cells increased 3-14 fold after vaccination in 2/5 pts and was high and did not change in one pt (0.8% of CD8+ T cells). Serum IL-10 was not detectable before or after vaccination although IL-12 increased 45.5 } 21%. No humoral response was detected in ptsL sera by FACS after incubation with the live tumor cells that comprise the vaccine, although some melanoma proteins were detected by western blots after vaccination. With a mean follow-up of 38.5 (22-68) months post-surgery the stage IIC pt and 7/8 stage III patients are NED; instead, 7/7 stage IV pts have progressed. We conclude that DC/Apo-Nec vaccine is safe, can induce specific immunity against melanoma Ags and suggest that in stage III pts it could augment the disease-free survival in the adjuvant setting.