Topical treatment of melanoma metastases with imiquimod, plus administration of a cancer vaccine, promotes immune signatures in the metastases

This study was designed to assess whether topical treatment of melanoma metastases with the TLR7 agonist imiquimod plus administration of a multipeptide cancer vaccine will improve immune cell infiltration of melanoma metastases.Patients and methods Eligible patients were immunized with a vaccine comprised of 12 melanoma peptides and a tetanus toxoid-derived helper peptide, and imiquimod was applied topically to metastatic tumors daily. Adverse events were recorded, and effects on the tumor microenvironment were evaluated from sequential tumor biopsies. T cell responses were assessed by IFN γ ELIspot assay and T cell tetramer staining. Patient tumors were evaluated for immune cell infiltration, cytokine and chemokine production, and gene expression.Results and conclusionsFour eligible patients were enrolled, and administration of imiquimod and vaccination were well tolerated. Circulating T cell responses to the vaccine was detected by ex vivo ELIspot assay in 3 of 4 patients. Treatment of metastases with imiquimod induced immune cell infiltration and favorable gene signatures in the patients with circulating T cell responses. This study supports further study of topical imiquimod combined with vaccines or other immune therapies for the treatment of melanoma.
Source: Cancer Immunology, Immunotherapy - Category: Cancer & Oncology Source Type: research