Autologous tumor lysate-loaded dendritic cell vaccination combined with Sunitinib for metastatic renal cell carcinoma

Abstract

Background The antibodies that block immunological checkpoints have been successfully applied for the treatment of cancer. Similar effects are expected by molecular targeted therapy, which primarily aims to inhibit molecular pathways for tumor cell growth and survival. Such small molecular drugs may modulate the immune system, which raises the possibility that targeted therapy might be effectively combined with immunotherapy. Sunitinib, a tyrosine kinase inhibitor currently in use for the treatment of metastatic renal cell carcinoma (mRCC), has been reported to modulate immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). We conducted a clinical study of dendritic cell (DC)-based immunotherapy together with Sunitinib in mRCC patients in an effort to enhance immunotherapeutic efficacy by inhibiting immunosuppressive cells. Methods Patients aged ≥20 years with advanced or recurrent mRCC who underwent nephrectomy were eligible for this study. Autologous tumor samples were obtained by surgery and used for preparing autologous tumor lysate. Leukapheresis was performed to obtain peripheral blood mononuclear cells (PBMCs). DCs were generated from adherent PBMCs in the presence of recombinant human granulocyte macrophage colony-stimulating factor (GM-CSF) (500 IU/ml) and IL-4 (500 IU/ml). Mature DCs were loaded with autologous tumor lysate by electroporation. Eight patients were enrolled in the study and received Sunitinib at a dose of 50 mg p.o. daily for 28 days followed by 14 days of rest. Tumor lysate-loaded DCs were administered subcutaneously every two weeks, with concomitant Sunitinib. Results