A phase I/II trial of the multipeptide cancer vaccine IMA910 in patients with advanced colorectal cancer (CRC).

555 Background: Treatment interruption after 12 weeks of oxaliplatin-based therapy followed by re-introduction upon signs of progression results in better overall tolerability and quality of life compared to continuous therapy while survival rates are only modestly impaired. Specific immunotherapy may provide a safe and tolerable intervention to prolong time to re-introduction and eventually overall survival. IMA910 is a novel peptide-based cancer vaccine consisting of 13 tumor-associated peptides (TUMAPs), which are naturally presented on MHC molecules of colorectal tumors. Methods: HLA-A*02+ advanced CRC patients being at least clinically stable after 12 weeks of first-line oxaliplatin-based therapy were enrolled. After immunomodulation with a single low dose of cyclophosphamide (300 mg/m2), patients were immunized intradermally (up to 16 vaccinations) with IMA910 in combination with GM-CSF (cohort 1; n=66) or IMA910 with GM-CSF plus topically applied imiquimod (cohort 2; n=26). T-cell responses to indi...