Trial Information

Immunization of Patients With Tumors Expressing NY-ESO-1 or LAGE Antigen With Complex of NY-ESO-1 Protein and Cholesterol-bearing Hydrophobized Pullulan (CHP)

NY-ESO-1 was isolated by serological analysis of recombinant cDNA expression libraries
(SEREX), using tumor mRNA and autologous serum from an esophageal cancer patient. Reverse
transcription-polymerase chain reaction (RT-PCR) analysis showed that NY-ESO-1 displayed the
typical expression pattern of CT antigens. NY-ESO-1 mRNA was expressed only in testis of
normal tissues tested and in various types of cancer, including lung cancer, breast cancer,
malignant melanoma and bladder cancer. LAGE-1 was identified by the representational
difference analysis and revealed to display 84% amino acid homology with NY-ESO-1. In most
cases, expression of LAGE-1 parallels the expression of NY-ESO-1. Since testis is an immune
privileged organ where HLA molecules are not expressed, these antigens can be considered
tumor-specific.

Because of frequent NY-ESO-1 mRNA expression and high immunogenicity in advanced cancer,
NY-ESO-1 is an attractive target molecule for a cancer vaccine. Current therapies against
advanced cancer have limited effectiveness. The idea of vaccination with NY-ESO-1 protein
in cancer patients with tumors expressing NY-ESO-1 mRNA is based on two findings: 1) the
number of CD8+ T cell epitopes identified in NY-ESO-1 molecule are limited to those binding
to HLA-A0201, A31, Cw3 and Cw6. These HLA subtypes are carried by a minor Japanese
population; 2) CD8+ T cell responses specific to NY-ESO-1 are polyclonal. Protein
vaccination may induce immune response more effectively against tumors expressing NY-ESO-1
than peptide immunization.