Clinical responses in patients with advanced colorectal cancer to a dendritic cell based vaccine

Patients with disseminated colorectal cancer have a poor prognosis. Preliminary studies have shown encouraging results from vaccines based on dendritic cells. The aim of this phase II study was to evaluate the effect of treating patients with advanced colorectal cancer with a cancer vaccine based on dendritic cells pulsed with an allogenic tumor cell lysate. Twenty patients with advanced colorectal cancer were consecutively enrolled. Dendritic cells (DC) were generated from autologous peripheral blood mononuclear cells and pulsed with allogenic tumor cell lysate containing high levels of cancer-testis antigens. Vaccines were biweekly administered intradermally with a total of 10 vaccines per patient. CT scans were performed and responses were graded according to the RECIST criteria. Quality of life was monitored with the SF-36 questionnaire. Toxicity and adverse events were graded according to the National Cancer Institute's common Toxicity Criteria. Four patients were graded with stable disease. Two remained stable throughout the entire study period. Analysis of changes in the patients' quality of life revealed stability in the subgroups: 'physical function' (p=0.872), 'physical role limitation' (p=0.965), 'bodily pain' (p=0.079), 'social function' (p=0.649), emotional role limitation' (p=0.252) and 'mental health' (p=0.626). The median survival from inclusion was 5.3 months (range 0.2-29.2 months) with one patient still being alive almost 30 months after inclusion in the trial. Treatment with this DC-based cancer vaccine was safe and non-toxic. Stable disease was found in 24% (4/17) of the patients. The quality of life remained for most categories high and stable throughout the study period.