Study of IMF-001 in Patients With Malignancies Expressing NY-ESO-1

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 cancer testis antigens (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. Since testis is an immune privileged organ where HLA molecules are not expressed, these antigens can be considered tumor-specific. IMF-001 is a CHP-NY-ESO-1 complex consisting of recombinant NY-ESO-1 protein and cholesteryl hydrophobized pullulan (CHP). CHP forms colloidally stable nanoparticles in water and complexes with substrate such as NY-ESO-1 protein. It is well known that exogenous antigen proteins can induce specific CD4+ T cells but not specific CD8+ T cell. Dendritic cells pulsed with IMF-001 induced NY-ESO-1 specific CD8+ T cells in blood samples of 4 healthy volunteers. These data suggest that immunization of patients with IMF-001 can evoke not only specific CD4+ T cells responses but also specific CD8+ T cell response to NY-ESO-1 more effectively than NY-ESO-1 protein alone. Similar results for both cellular and humoral immunity in response to NY-ESO-1 protein were observed in previous clinical investigational studies with IMF-001.